Others experience re: subs and Magmepan 20


I have a pair of Magnepan 20r’s. Have enjoyed them for years. In my room they go to about 30Hz, response way down at 25Hz.

I am experimenting with a pair of Janis subs. This gets the response to about 25 Hz then down a lot at at 20Hz. It adds a little something but not I am not bowled. over. I hear and feel a bit (in my chest) on some music.

I would like to hear about others have experience with adding subs to nearly full range speakers?

Did you feel you got your money’s worth for "a few silly Hz"?

Thanks
imdoc
Subs work best with full range speakers, but you have give them the same attention you would give any other part of the system. I'm not saying this is you, but more often than not, someone will put a nice system together, and then buy subs as an after thought. Its a nightmare to integrate a system like that. The sub needs to be in the same league as your other components.

Your situation is a bit more difficult because its always a challenge to integrate a driver with a panel. But it can be done. I'm not too familiar with your current setup, but you need a sub thats meant for music, not HT. I use Vandersteen subs and I have yet to see anything that comes close for the same money. Part of that is due to the first order xover's Vandersteen uses. Not many companies use them in their designs, but if you want the best integration, first order is usually the best way to go. Another option would be to try and find a good used pair of Kinergetics. A lot of people with panel speakers used them.
A re-post of a prior good background read

http://ultrafi.com/why-everybody-needs-a-good-subwoofer/

August 3, 2008 …And Why a Really Good Subwoofer is so Hard to Find

Audiophiles and music lovers are missing out on one of the most dramatic improvements they can make to their audio system: Powered Subwoofers. Most audiophiles won’t even use the word “subwoofer” in public, let alone plug one in to their precious systems. There is a kind of snobbery that exists in the world of high-end audio aimed primarily at receivers, car audio, home theater and especially subwoofers. As a matter of fact, subwoofers are responsible for many people disliking both car audio and home theater, since it is the subwoofer in both of those situations that tends to call attention to the system and cause many of the problems.

The truth of the matter is that subwoofers have fully earned their bad reputation. They usually suck. Most of them sound boomy, muddy and out of control with an obnoxious bass overhang that lingers so long as to blur most of the musical information up until the next bass note is struck. We have all had our fair share of bad subwoofer experiences, whether it’s from a nearby car thumping so loud that it appears to be bouncing up off the road, or a home theater with such overblown bass that it causes you to feel nauseous half-way through the movie. You would think that high-end audio manufacturers would be above all of that, but you would be wrong. In many cases, their subwoofers are almost as bad as the mass-market models because they too, are trying to capitalize on the home theater trend that is sweeping the land.

You see, it’s very difficult and expensive to build a good subwoofer. One reason is that a sub has to move a tremendous amount of air, which places big demands on the driver (or drivers). Moving lots of air requires a lot of power and that means an amp with a huge power supply, which can cost huge money. Finally, in trying to move all of this air, the driver (or drivers) which operate in an enclosure, create tremendous pressure inside of the box itself. The cabinet walls must be able to handle this pressure without flexing or resonating. Building such a box involves heavy damping and bracing which gets very expensive. When you consider these requirements, you quickly realize that it is virtually impossible to build a really good subwoofer (I mean good enough for a high-end music system) for under $1000. Yet most of the subwoofers out there sell for between $500 and $900. Manufacturers do this because their marketing research has shown them that that is what people want to spend on a sub, never mind the fact that what people want to spend and what it takes to get the job done right may be two different things. The result is that even most high-end manufacturers are putting out poorly constructed subwoofers that just don’t sound very good.

I don’t want to give you the impression that anyone who really wants to can build a good subwoofer so long as they are willing to throw enough money at the problem, because that really isn’t true either. There are some pretty expensive and well-constructed subwoofers out there that you would never want to plug into your music system because they would most certainly make the sound worse. Why? Because of their crossovers. A crossover is inserted into your signal path in order to remove the lowest frequencies (the deep bass) from your main speakers so that they no longer have to do all of the dirty work. The deep bass will instead be dealt with by the subwoofer. The #1 benefit of adding a high quality subwoofer to your system is not how it further extends the bass response, but how it can dramatically improve the sound of your existing power amp and main speakers from the midrange on up. That, my friends, is by far the most compelling reason to add a sub to your high-end music system. Once your main speakers are freed from the burden of making deep bass, they will sound cleaner, faster and clearer, especially in the midrange and midbass. They will also image way better because there will be far less air pressure and therefore resonance and vibration affecting their cabinet walls. And since the power required to make the deep bass is provided by the subwoofer’s built-in amplifier, your main power amp will be free from that burden and begin to sound like a much more powerful amplifier. The one big problem with all of this is that you need a crossover to roll off the deep bass in your system and achieve all of these benefits. And the crossover that comes with almost every subwoofer on the market will cause more damage to your signal than can be overcome by these benefits. That is the main reason that audiophiles refuse to consider adding subwoofers, even very expensive ones with well built cabinets.

Enter the Vandersteen 2Wq 300 watt powered subwoofer. This is the only subwoofer that is specifically designed to be inserted into the highest of high-end music systems without doing any harm to the precious signal. So how does Vandersteen do it? Simply. In fact his crossover scheme is so ingeniously simple that it’s a wonder nobody else thought of doing it the same way. I’ll spare you an in-depth description and just say that the only thing you end up inserting into your system is a couple of high quality capacitors. That’s it, nothing more! No additional wires or gadgets enter your signal path. Hell, you don’t even have to disconnect the wire between your amp and speakers to add this subwoofer. The model 2Wq sub uses the same basic crossover scheme as the $15,000 flagship Model 5As. As a matter of fact, you can even run the specially designed Model 5A crossovers (M5-HP) with the 2Wq if you want the most transparent sound imaginable.

So what about the other reason to add a subwoofer to your system: for more powerful and extended bass? I don’t care how big your main speakers are, they’re no match for a good subwoofer in the bass. A really good subwoofer can run rings around the best floorstanding speakers when it comes to bass extension, power and control because it is designed to be good at that and nothing but that, whereas main speakers have to be good at higher frequencies as well. Ideally, you want two subwoofers so that you have true stereo separation down deep into the bass. Stereo subs can also help to lessen room interaction problems by providing two discrete sources of bass information. Remember, if you can’t afford to buy two subwoofers at once, you can always add the second one later. Adding a pair of 300 watt powered subwoofers is exactly like adding a pair of 300 watt monoblock amplifiers to your system and upgrading to a pair of better main speakers at the same time. The beauty is that you don’t have to replace your main power amp or speakers to do it.

But there is a problem here as well. Everything comes at a price, and the price you pay with most subwoofers is that when you add them and their built-in amplifiers to your system, they don’t tend to blend or integrate well with the sound of your power amp and speakers. This is especially true if you own a tube amp, because the character of your amp is nothing like the character of the big solid-state amp that is built into most subwoofers. The result is that your system sounds split in half. You can hear where one part of the system leaves off (namely your amp and speakers) and where the other part takes over (the sub and its amp). This is a HUGE problem for audiophiles who aren’t willing to destroy their system’s coherence for additional power and bass extension. Fortunately, Vandersteen has the perfect solution for this problem that is, again, so simple, I wonder why nobody else thought of it first. His solution is to build a very powerful 300 watt amplifier that strictly provides the huge current needed to drive the subwoofer. You can think of this amplifier as only half of an amplifier; or just the power portion of an amplifier. The release of this power is controlled by the signal that is provided by your power amp. Vandersteen’s amplifier needs a voltage to modulate its current output, and what better place to get that voltage than from your main power amp? This way, your power amplifier is directly responsible for the sonic character of the deep bass coming from the subwoofer because it provides the necessary voltage signal. This voltage signal contains the unique and characteristic sound of your main power amplifier and insures that that character is maintained in the sound of the subwoofer itself. The beauty of it is that your amplifier is only providing a voltage reference and no actual current, so it is not taxed with the burden of “driving” the subwoofer in any way. As a matter of fact, your amplifier doesn’t even know that the sub is connected to it. The 2Wq’s potential is almost unlimited given that it will ratchet up its performance as you improve your power amp. Remember that you always want your subwoofer to sound just like your power amp. No better, no worse. NO DIFFERENT!

After having spent time with the amazing Vandersteen Model 5A loudspeakers with their 400-watt powered, metal cone subwoofers, we were reminded of the sound we had with the awesome Audio Research Reference 600 mono power amps. With the Ref 600s there was a sense of effortlessness, openness and unrestricted dynamic freedom that we have only otherwise heard with live unamplified music. Listening to those monstrously powerful amps made us realize that all other systems sound compressed by comparison. Only when we heard the new Vandersteen Model 5As with their hugely powerful built-in subwoofers, did we again have a strikingly similar sonic experience. The reason is that the Model 5As provide a total of 800 high-quality watts, to which you have to remember to add the power of the amp we were using, the ARC VT-100, at 200 watts. This means we were listening to about 1000 total watts of amplifier power – not far from the 1200 total watts provided by the Ref 600s. With the Vandersteen subwoofer crossover and amplifier, you are able to get those hundreds of subwoofer watts to blend seamlessly and even take on the character of the ARC VT-100. It’s amazing! What’s even better is that the price of the system with the Model 5As and the VT-100 is under half the cost of the Ref 600s alone! Since this discovery, we have achieved the same kind of unbelievable dynamics and seamless blending with ProAc loudspeakers and twin Vandersteen 2Wq 300 watt powered subs. So, if you want the sound of Ref 600s but cannot afford them, buy a pair of Model 5As or your favorite pair of ProAcs plus a couple of 2Wq subwoofers and mate them with a VT100 and you’ll get surprisingly close. You can cut the cost even further by running a pair of Vandersteen 2Wq 300-watt subwoofers with your existing speakers. Or mate a pair of 2Wqs with your favorite ProAc. In any case, it is the magic of SUBWOOFERS that allows this to happen. It is for all of the above reasons that there is only one subwoofer in existence capable of integrating seamlessly into a high-end music system, allowing you to reap all of the benefits of having a subwoofer, with none of the drawbacks. And the Vandersteen 2Wq is the one. And just in case you think I am a biased source, our correspondent Blaine Peck (who, for all you know is also a biased source) recently wrote the following, with no discussion between us about the topic prior to his sending us his comments. Whether reproducing the plucked string of an acoustic bass or the sound of an analog synthesizer, the Vandersteen 2Wq subwoofer is a seamless extension of any system. Nothing else need be added! With its internal 300-watt power amplifier, it is the perfect compliment to any sound system. Designed to take on the characteristics of your main stereo amplifier, the amp in the 2Wq will not sound foreign in your system. Also, through an extension of the Vandersteen design philosophy, a unique gradually sloping crossover system is implemented so you simply do not know where your main speakers stop and the 2Wq begins.

Now that your main speaker/amplifier combination need not concern themselves with those power demanding low frequencies, they are freed up to work in a more comfortable range. Yes, now what is coming from your main speakers will sound better than ever.

The 2Wq is not just another subwoofer. It consists of three 8″ floor-facing drivers, each with a massive motor. So why not a more typical single 12″ or 15″ design? Well frankly, the mass of a larger driver will not allow it to respond as quickly as the Vandersteen 8″ drivers to today’s demanding recordings. The 2Wq’s 8″ drivers are designed to handle the content but be “fleet of foot” at the same time. Concerned about where to put them? You need not worry. With the control of both its respective level and the “q” (how loose or tight the low end is) you have the flexibility to place them in a location that fits your living environment and not sacrifice performance. The simple beauty of this product will soon become an addition to your room.

So whether on orchestral music, hard rock or something in between, the Vandersteen 2Wq will exceed your expectations.


Thanks for reply.

My question is less about what equipment and integration issues (that would a whole, complicated discussion alone) but rather other folks experiences who have tried this and do they feel they got substantial benefit from an extra half octave added to (almost) full range speakers to justify the expense, hassle and real estate taken up in the music room.


Thanks

akg_ca

There is a kind of snobbery that exists in the world of high-end audio ...  ... the crossover that comes with almost every subwoofer on the market will cause more damage to your signal than can be overcome by these benefits ... I don’t care how big your main speakers are, they’re no match for a good subwoofer in the bass. A really good subwoofer can run rings around the best floorstanding speakers ... Vandersteen has the perfect solution ... there is only one subwoofer in existence capable of integrating seamlessly into a high-end music system, allowing you to reap all of the benefits of having a subwoofer, with none of the drawbacks. And the Vandersteen 2Wq is the one ...  the Vandersteen 2Wq subwoofer is a seamless extension of any system ... the Vandersteen 2Wq will exceed your expectations
There is no one subwoofer, there is no one component, that is perfect in every system. The world of audio just isn't that simple.


My friend works for one of the top 5 orchestras in the US. He listens to live classical music onstage, backstage and from the audience perspective almost every day. He owns 20.7s and a pair of REL subs which are fed line level signal and run <80hz. It's a big improvement in his room vs. the 20.7s alone. He wasn't happy before getting the subs. Not that it matters much in the context of the question but FWIW, he runs Rogue M180 monoblocks, and uses both vinyl and digital as sources. 
OTOH, I run Sound Lab A3s in a medium sized room(23x17x8") and can't imagine that subs would make a big difference in my own system. 
BTW, for use with electrostatics Rhythmic is another manufacturer that I've heard a few folks say is a potentially great match. Cheers,
Spencer
I used to use Janis Subs back the in late ’70s & early '80s. The crossover was 100 Hz. Is yours lower than that? 100 Hz is way too high for those Maggies.
I use two Rythmik F12G with my Magnepan 3.7i's and have the crossover set at 60.  The coherence is pretty good, but there's a slight dip at around 70hz.
+1 for Akg. I think the Vandersteen subs coupled with the crossovers will be the best possible combination for your Maggies.
But, since you were asking not for recommendations, but opinions regarding subs, I would have to say that whether ' they feel they got substantial benefit' would depend upon their integration as well as what subs they are using.
Though you can get the low frequencies, you have to remember that those frequencies must be reproduced in a balanced level with your main speakers. Once they stray significantly from a flat response (as well as phase), you loose all semblance of realism. I am sure others can explain this better, but I tried.
B

First iteration of monkeying around: Janis subs are crossed over at 35 Hz at  24 db/octave


Thanks to all who have responded

"....My question is .... but rather other folks experiences who have tried this and do they feel they got substantial benefit from an extra half octave added to (almost) full range speakers to justify the expense, hassle and real estate taken up in the music room..."

In short....you betcha....a big-time audio performance improvement BUT only if done "right" as highlighted in the reposted article.

I have seen and heard too many subwoofers introduced that simply bloat , muddy, chuff and destroy the audio reproduction simply because they were a crap and  crummy match to the 2-channel speakers primarily because they were indeed cheaply built kit .... full stop.
To CLEEDS
"....
There is no one subwoofer, there is no one component, that is perfect in every system. The world of audio just isn’t that simple...."

I never said it was the final single bests-all-comers solution ..... it wasn’t my article ...just a link to a third party article with a quality background read highlighting on the strengths and warts of ALL subwoofers, ( note the article title ) that also happened to include that writers suggested fave in closing that you can reject if you want to.

I know, you know, we ALL know that there is no one-size fits all to perfection choice, to quote your metaphor.

The Vandy is a very very fine contender AT ITS PRICEPOINT in a large arena of pretenders ,

BUt

I would gladly upgrade further to, say .... an ATC C-1 subwoofer that starts out north of $10,000 and goes  up,(if I could afford it) as just one simple example.
OP, at what freq. is the 20R 3 db down?

and what music do you listen to that has much energy at or below that freq.?
@imdoc , I think you are crossing over too low and the 3rd order crossover (correct me if I'm wrong) is a bit extreme. I would use something less drastic, like a 1st order crossover (-6db) starting at 70-80hz. If you have a well made powered sub, it should integrate and provide you with the bass you are looking for.
Not to beat a dead horse, that is why the Vandersteen crossover and subs do so well in terms of integration.
@akg_ca , If I, or 98% of the Audiogon readers could afford a $10K sub, then, yes, it might make a difference, but considering the OP has a pair of not quite current Maggies (and I wish I had 'em), I doubt he/she would entertain a pair of ATC C1's.
For comparison, I have an office system with a pair of Hsu VTF-1's paired with Zu Omen bookshelves. The Hsu, in no way compete with a pair of Vandy subs (which I used with a pair of Zu Union). I was blown away when I played music on them with my Atma's. So, using your Janis subs would kind of be like using my Hsu's, but YMMV.
B

"My question is less about what equipment and integration issues (that would a whole, complicated discussion alone) but rather other folks experiences who have tried this and do they feel they got substantial benefit from an extra half octave added to (almost) full range speakers to justify the expense, hassle and real estate taken up in the music room."

You can't separate the two. If you put 2 different solutions in your system that both get that extra half octive, they can sound completely different. It's a matter of quality and system matching. Just getting the system to play lower notes won't cut it in your system. I'm not a huge fan of Magnepan, but if there's one thing they do well, its bass. They take the quality over quantity path, and it sounds great. The only downside is that it's harder to integrate a sub.
randy-11

Stereophile test CD with 50, 40, 31.5, 25 and 20 HZ tones and a Radio Shack analog meter at the listening position I am pretty flat at the 31.5 Hz band (compared to the higher frequencies) and down 10 db or so at 25 without the subs


Music is virtually all/any but mainly rock, folk, classical.

But there are certain songs that I think I'm missing a bit of really low end:

Quick examples

"With God on our side" Neville Brothers

"Sista"  Rachelle Ferrell

"Solomon Sang" Cassandra Wilson


With or without the subs, things sound great;  I can't identify where the sub is located. Two of us listening can identify a little more low end with the subs, but not much.

With the subs, there is a bit of vibration in my chest - sort of fun (at first) but not what I get at the symphony hall and I suspect it will wear thin.

The subs are down at least 10 db at 20 Hz.


akg_ca

I was reading through The Chronicles of Narnia and came across this.

"It’s amazing! What’s even better is that the price of the system with the Model 5As and the VT-100 is under half the cost of the Ref 600s alone! Since this discovery, we have achieved the same kind of unbelievable dynamics and seamless blending with ProAc loudspeakers and twin Vandersteen 2Wq 300 watt powered subs. So, if you want the sound of Ref 600s but cannot afford them, buy a pair of Model 5As or your favorite pair of ProAcs plus a couple of 2Wq subwoofers and mate them with a VT100 and you’ll get surprisingly close. You can cut the cost even further by running a pair of Vandersteen 2Wq 300-watt subwoofers with your existing speakers. Or mate a pair of 2Wqs with your favorite ProAc. In any case, it is the magic of SUBWOOFERS that allows this to happen."

If you ever get a chance to hear a pair of Quicksilver V-4's in a system like this, thats based on a VT-100, try them. As much as I liked the VT-100, I felt that the V-4's performed at a higher level.

imdoc---akg_ca’s repost included a few assertions (well, a lot more than a few, and I didn’t make it through the whole thing :-) that must be disputed.

1- "it is virtually impossible to build a really good subwoofer for under $1000. Yet most of the subwoofers out there sell for between $500 and $900."

First, it is NOT impossible to build a really good subwoofer for under $1000. There are a fair number of Maggie owners very satisfied with their Rythmik F12G subs, to name just one under $1000 sub. I have heard the Vandersteen subs, very fine products, on many occasions, and while not wishing to pit Vandersteen against Rythmik, I can safely say that anyone who is satisfied with the Vandersteen is very unlikely to not also be so with the Rythmik. In fact, one’s preference might flip after having heard both.

But come on akg, do you really think the owner of Magnepan MG20r’s is limited to a sub-$1000 (no pun intended) subwoofer?! There are a number of incredible subs available which are valid competition to the Vandersteens, if funds are available.

2- "This is the only subwoofer (referring to Vandersteen of course) that is specifically designed to be inserted into the highest of high-end music systems without doing any harm to the precious signal."

What a ridiculous, arrogant statement! That is patently false. Whoever wrote that sentence must be woefully ignorant of the products of a number of designer/manufacturers who set their sites on that exact goal. Richard Vandersteen is not the only talented speaker designer out there, for gawds sake! I could name a few, but I’ll just mention Danny Richie and Brian Ding, of GR Research and Rythmik Audio respectively. Brian Ding designed his line of subs (which incorporate Mr. Dings patented Direct Servo-Feedback technology) for music reproduction, and Danny Richie and he collaborated on a 12" driver offered with either an aluminum cone (for high volume application, including loud music and/or home theater) or a paper one (the "G" in the model designation of the Rythmik F12G, which uses the paper-cone version of the woofer, refers to GR Research) specifically for music listened to at less than extreme volume, it’s lower mass providing higher low-level resolution.

In addition, they also collaborated on a very unique subwoofer designed specifically for "the highest of high-end music systems"---an open baffle/dipole sub (two 12" woofers mounted in an OB "H-Frame", powered by the Rythmik Servo-Feedback amplifier), the ultimate design for mating with a dipole speaker such as Maggies (and ESL’s, and Ribbons). The GR Research/Rythmik Audio OB/Dipole Sub is, and I say this with the upmost respect, a completely different animal than the Vandersteen, and all other, sub(s). Is the writer of the quoted sentence even aware of GR Research and Rythmik Audio products, or all the other high-end designs now available?

3- "In fact his (Vandersteen) crossover is so ingeniously simple that it is a wonder nobody else thought of doing it the same way."

It IS simple, and it WOULD be a wonder if nobody else thought of doing it the same way. But they DID, and a long, long time ago! Advanced enthusiasts having been employing a simple 1st order crossover as a high-pass filter since the 1950’s. You don’t really believe no one before Richard Vandersteen thought of something so obvious, do you?! The Dahlquist x/o in the 1970’s used that exact technique---a single capacitor to filter the signal going to the main speakers.

Now, if you’re talking about Richards technique of taking the signal for the sub from the speaker taps of the main power amp, Richard is not the only one doing that either. Both Rythmik Audio and REL offer the same hookup, Rythmik also providing line-level connections.

All of this is not to say that the Vandersteen subs are not very fine products. Far from it---they are great. But they are not the only really good ones available for use in "the highest of high-end music systems". They do have some competition, and may in fact have some which surpass them. There are even Magneplanar fanatics who use the Tympani T-IV bass panels as subs for their MG series Maggies!

imdoc,

     I'm also a Magnepan user but not with quite as good of a model as you own. I've had a pair of older 2.7qrs for about the last 25 yrs  that are rated to go down to 37 hz while your 20Rs are rated as going as low as 25 hz.
     I've been searching for a good bass system to pair with my Magnepans for over 2 decades. The only sub system I've discovered that has very good bass response down to the lowest audible octaves that is more impactful but just as natural, textured, detailed and articulate as the bass my Magnepans produce down to their limits and blends in seamlessly is a Distributed Bass Array System (DBAS).  

    There are actually 2 DBAS that I'm aware of:

1. The Audio Kinesis SWARM which I believe is the original.  It's based on the PHD thesis of an acoustical engineer, Dr.Geddes, on the subject of achieving good and well dispersed bass performance in smaller rooms (as opposed to large venues such as concert halls and auditoriums) and the work of another acoustical engineer, Dr. O'Toole.

2.  The Audio Kinesis DEBRA(Distributed EQ Reflex Array) which is basically the same as the SWARM with minor variations in sub construction that is built and sold by James Romeyn Music and Audio in Utah.  James is a friend and partner of Audio Kinesis owner, Duke LeJeune, and has a licensing agreement with Audio Kinesis to build and sell his version under the Audio Kinesis brand.

     About a year ago I purchased the Audio Kinesis DEBRA  system.Here's a link describing the system:


http://jamesromeyn.com/old-pages/home-audio-gear/dsa-1-0-distributed-subwoofer-array-5-pieces-4k-usd...


Since it is such an ideal system for me and I think it would work well in your system, I provided a link to  the Absolute Sound's 2015 review of the Audio Kinesis SWARM (which awarded it a 'Golden Ear' award for that year) below:

http://www.theabsolutesound.com/articles/audiokinesis-swarm-subwoofer-system/

.

    I can personally attest to the effectiveness of the DEBRA system in my room. I have 6 listening/viewing positions in my combination music and ht system in my living room. Bass response is equally good for music and HT at all 6 positions without the use of acoustic devices (no absorbing or diffusing panels or bass traps) and without any electronic equalization (room analysis/correction equipment, software or eq). I should mention I've never had my system/room analyzed using a mike and software.  

    From my purely subjective perspective, however, I'm confident the results would be good since I spent hours on the setup and critical listening from all six listening positions in my room. I would suggest this type of sub system as a viable alternative for anyone considering investing in one or more quality subs. The system is rated clean at 113 decibels at 20 hz and I've often heard and felt it go this low.  It feels and sounds clean and right but I can't verify the decibels or lack of distortion.

Hope this helped,

  Tim

a Moog might go a lot lower than 20 Hz on rock tracks

otherwise, sub 30 Hz sounds are pretty much limited to organ music and cannons (Tch. overture)

I’d bet some DSP testing and room treatments would be much more rewarding, tho maybe an amp that really put out a lot of current into 4 ohms(?? dunno what you have now)

Wendell can give you the factory talk on why to avoid cone based subs and to use a pair of DWMs instead

OTOH, many people are happy with (at least the expensive) subs added to the smaller panels
imdoc,

    Forgot to answer one of your questions:
Whether I thought the $3,000 cost of the  DEBRA was worth the cost?

     Unequivocally, yes.  I honestly can't count the number of times I've been listening to music and the music calls for deeper bass (acoustic, percussion or electronic) and the DBA system just powerfully, naturally and seemingly effortlessly reproduces the lowest octaves and blends so seamlessly with the Magnepans reproducing everything else that the result is a sound stage illusion that  just sounds like a beautifully synchronized realistic whole; like the actual musicians are playing in my living room or as if I've been transported to the venue, depending on the recording.
  Logically I know it's a sound stage illusion but it's uncanny how I perceive the bass, even though it is monaural, as emanating from the proper instruments within this illusionary and 3D sound stage.  It's really quite impressive and enjoyable.  .
   I think paying attention to details and being precise in setting up a DBA is critical to getting good results; things like following the progressive locating procedure for properly positioning each of the 4 subs in the room, using trial and error to set the crossover at the correct hz (I found 40hz worked best in my system),  determining the correct relative volume of the DBAS (in relation to your main speakers) by precise setting of the supplied sub amp's rotary volume control knob (mine is set between the 9 and 10 o'clock position) and whether to run your main speakers full range or use a filter to limit their lower frequency duties (Mine run full range without restriction).

    Fortunately, this rather elaborate setup process only needs to be done well once.  You're able to just enjoy your music with consistently stellar performance until you decide to move or upgrade your main speakers. 

     Lastly, I wanted to mention that you can also construct your own custom DBA by using 4 subs of your own choosing.  However, this is likely to be significantly more expensive than a DEBRA or SWARM complete system with the 'law of diminishing returns' also needing to be considered.

Thanks,
 Tim   
I currently have Magnepan 20.7's paired with a single REL G-1 sub-bass driven by ARC 250SE mono-amps. I have found the sub provides an additional fullness and body to music which has been linearly recorded and accurately transcribed to less than 30hz (CD or LP). The improvement in overall presentation is also dependent upon the room size, and in my case, I listen in a 15ft wide by 22ft long room. I would note that I previously had Magnepan 20.0s, and the improvement with a sub was somewhat greater due to its more limited low end.  Due to the inefficiency of Magnepans, ample dynamic power is essential and probably more important than the addition of a sub.     
I have a pair of Magnepan MGIIIa s and now that I have a preamp with dedicated subwoofer ouputs with adjustable crossover points, I was thinking of adding an REL or a Magnepan DWM to the system.  I am thinking more like an 8" sub, since I want a faster response than I think the larger subs will provide (do not really need super powerful bass) and my listening room is not large.

Jim, Rythmik Audio has two sealed subs featuring dual 8" woofers, the F8 and FM8. The only difference between them is the FM was designed to be used as a mid-bass woofer, it’s x/o to a lower-frequency sub being 4th order at 50Hz. Both operate up to 250Hz, and both incorporate the Rythmik Direct Servo-Feedback amplifier.

Also, co-designed by Rythmiks Brian Ding and Danny Richie of GR Research is the unique OB/Dipole Sub, available with dual 8" woofers, though dual 12’s is the more common choice. This OB/Dipole Sub is the ultimate sub for use with all planar speakers, for obvious reasons.

By the way, both Brian and Danny are adamant that because of the design of the 8" and 12" woofers (designed in house specifically for open baffle implementation, and custom manufactured by TC Sounds for Rythmik and GR exclusively), and how they are controlled by the Rythmik Servo-Feedback circuit, the 12" is just as "fast" as the 8", but capable of considerably more output. The sense of "speed" in a woofer is in how quickly it returns to "rest" after the signal has stopped, not how quickly it starts (Rythmik/GR subs have been described as "stopping on a dime"). Subwoofer frequencies are relatively "slow", but woofers, once set in motion, tend to stay in motion. That’s where the Rythmik Servo-Feedback circuit comes into play. If you’ve ever heard the Infinity IRS loudspeakers, you know what I’m talking about. I formerly owned the mini-IRS, the RS-1b (featuring six 8" servo-feedback controlled woofers per side), and the pair of Rythmik Audio/Gr Research subs I now own are considerably better. Leaner, cleaner, no boom, no bloat. It’s the only Open Baffle/Dipole Servo-Feedback Sub in the world! Seriously, if you don’t have room for a pair of Magneplanar Tympani T-IV bass panels (great as subs for Maggie MG series speakers), this is the sub to own.

I would look no further than REL and Sunfire.
I am not going to spend the time reading all the posts. My impression is this; it seems the sub doesn't get you much farther down than the mains. While it may seem marginal, a sub that can do about 15-16Hz is SUBstantially, different - sorry, had to pun! - than one which can do 25Hz. BIG difference. 

I would not give up on subs without considering an alternative, as I'm sure others have suggested. 

My experience; I have the Kingsound King III ESL and love them with subs. I use the Legacy EXTREME XD Subs with them and wouldn't dream of runnning the King III for realism in listening without subs. Sure, the King III reaches similar to the 20.7, but the extra foundation is precious on genres of music. Imo. 

Disclaimer, prior to owning I reviewed both the King III and the Legacy EXTREME XD Subs for Dagogo.com 
A fun thread to read and lots of great ideas, products, technical information, and opinions.  With years of enjoyable experience with MG II's through 20's including IIIa's with Entec and 3.6 and 3.7i with Rel Stentor III's subs as well as different amp and room scenarios here are a few key points to consider in chasing the extra octave.

I respect your position on not wanting to get into the details of amplication and room dimensions, however you talk about "you think you are missing a bit of low end" on some songs.  You have to consider the reality of inefficient high resolution speakers like Magnepans and others.  Like it or not, you will hear the strengths and weaknesses of up stream equipment as well as the differences in how the music was engineered and recorded.  Sub's can easily create the feel it in your chest sensation, but as you said its not the experience you had in the symphony hall.

My point is, you have to decide on what you want - move octaves or move closer to the recording.  With Maggie's what is up stream, room acoustics and speaker placement is how you get closer to the recording.  Had lots of fun with my subwoofer experience, mostly the MG 3.6 with the Rel Stentor III, in an 18x25 room with carpeted cement floor with a few carefully placed room acoustical panels with the speakers 50" out from the back wall.  Driven by CJ Art III and Levinson ML333 there was a big, dynamic and felt it sense to the recorded music especially well engineered and recorded music.  It was different with 3.7i mostly due to the improvements in the 3.7i causing much tuning with the Rel's.  Not a negative about the 3.7i's more the realization I was playing with an unnatural configuration.  At least in my mind.

The change I made and would encourage you to think about is.  Instead of chasing the extra octave, think about upgrading to the MG 20.7's and as JPMEURER2 stated - bring ample dynamic power over a sub system investment.  I swapped out my ML333 for the Sanders Magtech mono's.  

The sound is and feels more natural, especially with well engineered and recorded music. Don't forget not all recording are created equal and seriously play with speaker placement given available real estate over more equipment in the room.  I sense many Magnepan owners do not move the speakers far enough from the back wall. 

All the best.
randy 11,

You stated:" I’d bet some DSP testing and room treatments would be much more rewarding, tho maybe an amp that really put out a lot of current into 4 ohms(?? dunno what you have now)"

    I think your reply was directed at me but I'm not sure.  In case I'm correct, I wanted to respond:

     I use a pair of D-Sonic M3-600-M class D mono-block amps on my older Magnepan 2.7qr speakers; 1,000 watts into 4 ohms and 24 amp peak output current each.  They drive the speakers very well.

    I think DSP room analysis/correction would be interesting just to confirm my in-room bass frequency response and bass dispersion is as good as I think it is based on my subjective opinion.
   
    I'm certain my room has no need for bass room treatments such as bass traps or other dampening panels for either the bass system or the Magnepans but would like to experiment with diffusing panels behind and between 2.7qrs.

 Thanks,
  Tim
you might be surprised about the bass....

whether it is worth changing the look of the room is another issue
Hi randy 11,

    I try to keep an open mid about system changes and improvements.
    But I'm not certain what you mean by your last post comments.

   Could you please elaborate and provide more specifics?

Thanks,
  Tim
Small sound wave launch of an sub will not mate well with the six foot tall wave launch of the 20.

Image and sound field in the low bass will be screwed up!

Be satisfied with quality sound down to 25Hz.

The bragging rites of screwed up sound down to 20 Hz are not worth it! 


randy 11,

     You stated in a previous post, I believe in response to comments I had made about the attributes of my distributed bass array utilizing 4 subs and that I've never had my room's bass response analyzed via mics and software:

" you might be surprised about the bass....
whether it is worth changing the look of the room is another issue."

     Since I wasn't certain what you meant by the comment "you might be surprised about the bass", I requested you elaborate and be more specific in order to clarify your meaning.  
     Since you haven't responded in the few days since my request, I wanted to point out that your comment "you might be surprised about the bass" can be interpreted in 2 opposite ways:

1. It could mean that, if I analyzed the bass response produced in my room of my 4 sub DBA (Distributed Bass Array) system utilizing a mic and software, I would be surprised how well the in-room bass response actually measured.  
    I don't believe this is your meaning, since I would not be surprised in the least to discover that the excellent bass response I consistently perceive in my room is validated by excellent in-room measurement results.

2. It could mean that, if I analyzed the bass response produced in my room of my 4 sub DBA (Distributed Bass Array) system utilizing a mic and software, I would be surprised how poorly the in-room bass response actually measured.

    This is more likely your meaning, since I definitely would be very surprised to learn that the excellent bass response I consistently perceive in my room is not validated by equally excellent in-room measurement results.
     If this were the case, I'll admit I would be initially very confused.  How could something that I perceive as sounding so good measure so poorly?
I think my initial reaction would be that either the measuring equipment or the measuring method are at fault. Either the equipment is not properly measuring the in-room bass response or the specifics of what is being measured do not correlate to how bass response is actually perceived by our ears and brains.
    Even in the highly unlikely possibility that the bass response in my room was measured accurately as poor, however, I'm not sure I would search for an alternative bass system/subs to replace my current DBA.
    I say this because our 'perception' of the sound of our systems is our 'reality'.  
    If the bass system I utilize sounds as extended, as detailed, as seamlessly blended with my main speakers and as close to the real thing as the DBA does, how well or poorly it measures in my room is much less important to me than my perception of how it sounds.
     As I've stated, I use absolutely no mics, DSP, room analysis/room correction software, equalizers or room treatments.
     I am curious, though, how  my system/room's bass response would measure.
     I should point out that when Dr. Geddes and Toole performed testing on their DBA theory in numerous rooms of various sizes and shapes, however,  the bass response measurements of the rooms deploying a DBA system were consistently very good.  I have no reason to think my room using the DEBRA 4 sub DBA system would not measure the bass response at least as equally 'very good', if not even better.  
     

    And finally,  I'm also not certain what you meant when you stated:" whether it is worth changing the look of the room is another issue."
     Why and how would I change anything?


     I still hope you respond and clarify your comments.

Thank you,
  Tim  
if a living room it cannot be too odd looking

you  may well have standing waves as most rooms do, so need to test
randy 11,

    You haven't even explained your comments from your previous post and you're just going to make more cryptic comments?

     I'm not sure why you're avoiding coherent comments in your posts.

 Are you just a poor written communicator?

Are your comments deliberately incoherent and confusing?

Do you care that your comments are completely ineffective and of no value to those they're directed toward because they're so incoherent and confusing?

Are you capable of explaining, elaborating on or just plainly and directly clarifying your comments?

Am I the only one having difficulty making sense of your comments?

Are you just messing with me by being so cryptic?

     I'm honestly uncertain if any, all or some combination of the above explanations apply.  But since your comments are of so little value to me, I suggest you might want to make them understandable or just avoid responding.

Thanks,
  Tim
randy 11,

I forgot to respond to your only comment I understood thus far:

" you  may well have standing waves as most rooms do, so need to test"

    You are correct, most rooms do have bass standing waves
   However, the whole point of a properly setup DBA is to eliminate the vast majority of bass standing waves in the room it is deployed in.  
     The DBA's main benefit and reason for being is its extraordinary ability to eliminate the vast majority of bass standing waves in any room.
     This is why DBAs are such an excellent solution for providing top quality bass response in any system no matter one's room size or shape.and without the need for mics, room analyzing and correcting software, equalization, DSP equipment or room treatments.
     The result is powerful, life-like, detailed, seamlessly integrated with the main speakers and seemingly effortless bass that is well dispersed throughout the entire room; not just at a designated sweet spot.
     In my opinion, and I would think in the opinion of many, this describes  the type of in-room bass response we are all in search of.  

     Do I have any bass standing waves in my room since installing my Audio Kinesis DEBRA DBA system?  Maybe but so what?.  
     The sole instruments I have available to detect them are my ears and attached brain.  I have spent what I consider a large amount of time walking and even crouching around my entire living room searching for the symptoms of bass standing waves: any spots at which bass sounds over/under emphasized and spots at which bass sounds nonexistent.  
     I'm as certain as I can be, lacking the necessary equipment for a complete room analysis, that there are no bass standing waves at any of my 6 seating positions in my room.  Perhaps there's 1 or a few in my room but I'm not going to worry about it or them since they obviously have virtually no affect I can even remotely detect on bass performance in my entire room.

Thanks,
  Tim   
      

I designed the Swarm subwoofer system mentioned above, and worked with Jim Romeyn on his conceptually-similar Distributed Bass Array system.

The Swarm was originally designed with dipole speakers in mind, specifically Maggies and Quads. Briefly, dipoles have smoother in-room response in the bass region than monopoles do (according to a peer-reviewed paper by James M. Kates). Smooth bass is fast bass, subjectively and literally - in the bass region, in-room peaks happen where the energy decays more slowly, and vice versa. In fact, the two are so interconnected in the bass region that if you fix the frequency response, you have also fixed the time-domain response. So the key to matching the "speed" of dipoles is, match their in-room smoothness.

Two subs intelligently positioned will be roughly twice as smooth as one sub. Still not as smooth as two dipole main speakers, but definitely better than one sub. Four intelligently positioned subs will be twice as smooth as two, and comparable in smoothness to a pair of dipoles.

The improved in-room smoothness that arises from using multiple subs intelligently distributed may seem counter-intuitive, so let me try to explain: Imagine you are looking at the in-room frequency response of a single sub. You see a few big peaks and dips. The problem is not only their magnitude, but also how far apart they are - you see, the ear/brain system tends to "average out" peaks and dips that are within about 1/3 octave of one another, but these are almost always going to be further apart than that. Small rooms are typically worse than big rooms in this respect.

(Also, the ear is especially sensitive to changes in loudness - peaks and dips! - in the bass region. This is shown by the way that equal-loudness curves bunch up south of 100 Hz. So there is usually a LOT of room for improvement in the bass region.)

You can move the sub or move the microphone location and those big peaks and dips get shuffled and changed, but they do not go away. Now imagine that you add a second subwoofer in a different location. It too generates a big peak-and-dip pattern. But unless the second sub’s peaks and dips overlay the first’s (which can only happen if the two subs are in the exact same spot), the sum of the two will be significantly smoother than either one alone. Mathematically, it will tend to sum to half as much average deviation (or "twice as smooth"). The same trend holds as we add more subs. And not only are the peaks and dips smaller in the summed response, but they are also more numerous and therefore closer together, so the ear/brain system’s averaging characteristic comes into play, and the subjective improvement is probably greater than one might think from eyeballing the summed curve.

Anyway my point is, there is some solid acoustic and psychoacoustic science behind the distributed bass array concept. Credit to Earl Geddes for sharing his ideas with me and allowing me to use them.

Duke

Duke,

     Thanks for your very thorough explanation of how the Swarm and Debra DBAs were designed to work.  
     I can personally attest to how the Debra DBA actually does produce extraordinarily bass results in my 23ft x 16ft living room for both music (often hi-rez 24bit/96khz WAV files as well as ripped copies of redbook CDs) and as part of a 5.1 surround system for HT. I assume the almost identical Swarm would perform equally well in my system and room.
      The way this DBA system so seamlessly integrates with my older Magnepan 2.7QR main speakers is truly exceptional.  I believe either the Debra or Swarm DBA would likely be a very good solution for extending and improving bass response and impact in any room and likely integrate very well with any brand or type of main speakers.  But I agree the very fast and articulate bass produced by these DBAs are especially good for mating with Magnepans and any electrostatics. I also like the way they can effortlessly reproduce deep and powerful bass when the content calls for it.

      I'd definitely suggest the OP, imdoc, would be well served by auditioning either the Debra or Swarm DBA with his very nice Magnepan 20s in his room before purchasing any other bass solution.

Thanks,
   Tim

Thank you very much, Tim! Glad the Debra is working well for you!

The only question mark in my mind regarding imdoc’s situation is, whether his room has something going on (large area and/or open floorplan perhaps?) that results in minimal boundary reinforcement in that bottom octave. It sounds to me like his primary issue is a shortfall in bass quantity, to the extent that if there is a qualitative mismatch between subs and his big Maggies, it hasn’t been obvious yet.

Both the Debra and the Swarm are "voiced" with the expectation of about 3 dB per octave of gain from boundary reinforcement below 80 Hz or so. There is a fair amount of adjustability built in, between the equalization available in the amp and the other setup options, but it is possible that he needs more bottom-octave energy than our systems provide in their "stock" form.

So while I think we have a good solution in the room-interaction domain, in this particular situation I don’t know whether we’d meet the quantitative requirements. Not that the four 10" subs in the Debra and Swarm systems are wimpy (their motor strength is unusually high, and many of our customers have measured in-room -3 dB points around or below 20 Hz), but maybe he’d be better served by four 15" subs that are voiced "flat" rather than voiced with typical boundary reinforcement taken into account.

Duke

Hi Duke,

Very interesting and very important for the OP, imdoc.

I agree he may be better served with a custom distributed bass array but that he should use subs with even larger drivers for more bass quantity. The chosen subs should be ’voiced’ flat, not -3db down below 80 hz like the Debra and Swarm subs are to compensate for room gain in typical rooms. The main points being the use of larger and voiced flat subs would better suit imdoc’s desire for more deep bass response.
I know the Debra/Swarm DBA system is a great solution for mating seamlessly with Maggies and it does have good deep bass impact in my room and system; bass I do feel in my chest on some music and HT content. However, I’m more concerned with the quality of the bass than just the quantity. But I understand this doesn’t mean the Swarm/Debra’s bass will be sufficiently deep to satisfy imdoc.
Finding a good bass system solution for imdoc, one that integrates well with his large Maggies and also is capable of producing exceptionally deep bass on a consistent basis, may be possible but it would likely be extremely expensive.

Imdoc seems to be looking for a hi-end bass system at a bargain price. I think we’re all aware he’s not going to attain this with his pair of Janis subs no matter how hard he tries.

Before we can give any further meaningful advice, I think it’s important to have a description of his room and his budget.

Currently, my thought is he has 3 main choices in the form of good/better/best and depending on his room and budget:

Good= Obtain 1, or perhaps 2, additional Janis subs and experiment with placement for best performance. This is likely the least expensive option, although I’m not sure of the which Janis model sub he currently has, its cost or whether he has the room for 1-2 more subs.

Better= Purchase a Swarm or Debra complete DBA system for about $3,000. Very likely to blend well with his speakers but unsure if it will provide enough deep bass impact to satisfy.

Best= Create a custom DBA system using 4 subs that utilize 15" drivers and are ’voiced’ as flat. Definitely the most expensive option (likely at least $6,000 but actual cost dependent on subs preferred). Most difficult aspect will probably be finding subs that blend well with his large Magnepans but having the room for 4 larger subs is also a concern.


Thanks,
Tim
can you explain option 2 betterZ?

I get this:
https://www.google.com/search?q=Debra+complete+DBA+system&oq=Debra+complete+DBA+system&aqs=c...*
randy 11,

   You asked:  " can you explain option 2 betterZ?"

  Not sure, but I think you're looking for a link to the Audio Kinesis Debra system.  I would not use "DBA" on google searches.  This is just an acronym I created for "Distributed Bass Array" that I don't believe is in wide use by others.  Google   "Distributed Bass Array" and you'll get more relevant info like Dr. Geddes's research and James Romeyn's Debra system that I own.  Here's the link for the Debra:

http://jamesromeyn.com/old-pages/home-audio-gear/dsa-1-0-distributed-subwoofer-array-5-pieces-4k-usd...
randy 11,

     Just to be fair, here's a link to the almost identical Audio Kinesis Swarm DBA along with a link to a 2015 review of this system in the Absolute Sound:

http://www.audiokinesis.com/the-swarm-subwoofer-system-1.html

http://www.theabsolutesound.com/articles/audiokinesis-swarm-subwoofer-system/


["I would like to hear about others have experience with adding subs to nearly full range speakers?

Did you feel you got your money’s worth for "a few silly Hz"?"]

Silly Hz? Considering how silly post production can get, many recordings have the extra low rumble frequencies almost completely  EQd out while others have reclocked and compressed the lows to an "artsy?" one note boom. 

Do you want to simply set it and forget it and if there happens to be some low frequency you'll hear it or do you want the luxury of one touch remote preset control of most of the main ELF variables?

Yeah, those last few Hz are silly, silly like crack. I love my subs. 
Subwoofer technology has advanced greatly since 2008. There are now many good subwoofers available and a few reasonably priced great DSP subwoofers. 

 
Thx, the Audio Kinesis Debra system looks interesting

re silly - isn't that what audiophilia is all about?

but it's true there just isn't a lot of music with really low freq.s in it (unless you are a pipe organ freak, or keep repeating the canon portions of Tchak's 1812 over & over again)

Strange, we haven't heard from the OP, imdoc, since he posted this thread.

I was hoping he could describe his room and give his budget.
Re: an honest and honorable hi end guy

I had the opportunity to speak with Duke of Audiokinesis today.  It was an interesting conversation and we had an extended discussion regarding my setup and various constraints that are present. He evaluated things and felt his Swarm system was not the best solution for me.  He even suggested a competitor product to consider.

It is refreshing/unusual/nice/amazing to find someone in high end who really only wants what is the best for the customer.  

I would strongly recommend Audiokinesis and Duke if his products might be of interest. 


Hi imdoc,

     Welcome back to your thread.

     Great to hear you had a good discussion withe Duke.  I know he and James Romeyn can be relied upon to give very good and unbiased audio advise.
    In a previous post, Duke was confident that the Swarm/Debra would integrate well with your large Magnepans and your room but was concerned whether it would deliver the quantity of bass in your room that you seem to desire.
   Given your more powerful bass system preference, he thought you may require a distributed bass array that employed larger subs that would deliver even greater quantities of bass in your system.  

    For current and future readers of this thread and to satisfy my curiosity, can you tell us the competitor's product Duke recommended?

Thanks,
  Tim

Thank you for your kind words, imdoc! I enjoyed talking with you very much. One thing I forgot to mention - you’ll probably have to EQ in a fair amount of low-end boost in your room. I suspect that the big opening behind the listening area is acting sort of like a bass trap and reducing your in-room bass. You might also experiment with putting the two subs in phase quadrature (90 degrees apart) - it may be beneficial.

Tim, if you look up imdoc’s system (just click on his name), you’ll see a photo of his room. It is a beautiful space that is not a dedicated audio room, and in my opinion multiple subs distributed around the room would ruin the aesthetic he has achieved.

The room is open at the end that’s "behind your back" from where the photo is taken, so that room dimension is not distinct. The other room dimensions (width and height) don’t support room modes below 30 Hz, and he’s only looking to augment the Maggies south of 30 Hz, so the net value of the modal-region-smoothing we get from a distributed multi-sub system doesn’t apply as much. In this situation, I think the more cost-effective and aesthetically practical solution would be two high-output subs that fit in the areas behind his Maggies.

At first I was thinking that a pair of tall two-woofer subs dimensioned to fit behind the Maggies (and shaped to be Maggie-backwave-friendly) might work well, as with one woofer high and one low, we’d at least have our bass sources distributed in two dimensions (height and width). But then I thought about his room dimensions and the modes those dimensions would support and decided that the benefits would be minor, and that it would be more cost-effective for imdoc to just get two powerful conventional subs rather than paying to have expensive custom enclosures built. So I suggested he look at Rhythmik, though they are by no means the only viable choice out there.

Duke

imdoc,

     Nice room! It looks like an upscale chinese restaurant, very cool.

Duke,
     
    Thanks for describing your thought process considering a suitable  bass solution for imdoc's somewhat unusual room.  
    I understand your reasoning for suggesting a powerful pair of subs instead of a 3-4 sub array.  Hopefully, imdoc can find a pair that blends well with his Maggies and can position them well enough to reduce standing waves and give good bass response at all the dining positions.

Later,
  Tim 
Perhaps one from Column A and one from Column B?