Hello holter,
I'm not very familiar with the Dream Maker speakers, although I've read good reviews on them. I don't think you'd need any more than 4 AK subs to get excellent bass response in your room. I think James would be the best person to talk to about combining the Dream Makers and a Debra bass system since he's very familiar with both.
Tim
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Hi Tim
Yes, getting some DBA woofers may be an idea, maybe just 2 of the 4, since I already have a bit of distributed woofer / bass extension, using a pair of Audiokinesis LCS speakers along with the Dream Maker front speakers. However I am note sure. I still have some distance to cover, to get the two pairs of speakers to correlate optimally. It is wonderful to be able to do this in the analog domain, not through electronic bad-sounding equalizing. As far as it goes.
Some users prefer the Dream Makers alone, no LCS (or "space generators", a later Audiokinesis term), and I feel happy that I have the equipment to adjust the mix of the DM and the LCS optimally (like you can adjust bass volume and sub positioning on the DBA). For me, it means that the LCS are just BARELY notable. Yet I get better bass, along with a larger sense of air and space.
Since the Dream Makers augmented with the LCS woofers "grip" the room so well, I am not sure of the extra benefit of DBA, though I might be amazed of course.
Another consideration is, this is a living room not just a listening room. 4 more speakers, 8 total? Seems a bit much. I was trying to scale down. |
Hello holter,
I'm certainly no bass expert, either. James Romeyn mentioned to me how well his A K Debra system and its distributed bass array concept works and I just read all I could find out about the concept, mostly research done by Earl Geddes, Floyd Tool, Duke Lejeune and Todd Welti.
I learned a lot, its psychoacoustics basis made a lot of sense and James Romeyn's offer to let me try it out free in my room for a month convinced me to give it a try. I can't overstate how well the Debra/Swarm system works with my main speakers on music and ht.
You have a fairly large room at 20'x27', are already using A K main speakers and seem like an ideal candidate for a DBA system. I think you'll be amazed by the results. I'd suggest calling James Romeyn and see if he'll give you a 28-day in home trial period. I guarantee you won't be returning it.
Tim
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Hi Tim
Nice system - and interesting that we share some of the same experience, listening a bit more nearfield, for the best 3d immersive experience.
Bass and time coherence - I am no expert, just reporting what I heard. I first tried down-firing subs and next came to prefer front-firing ones. First, two Rel subs, didn’t get them to match the system, so next, one big Velodyne. I noticed better sound by positioning the subs precisely in relation to the woofers on the main speakers. But maybe it was room alignment more than time alignment. I did not use REW or other software, but mainly my ears. My audiophile imagination jumped to the idea that time does in fact influence the result. I very much agree with the idea that a main purpose of the sub(s) is to get the room ’in full swing’, smoothness, lack of boom etc. Still I wonder if distance to the subs plays a role also. Even if mainly indirectly / reverberant.Through the room, so to speak.
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Hello o_holter,
My room is 23'x16' with an 8' ceiling. I have some pictures posted on my profile if you want to take a look. It's a combo music and ht system.
I have a 65" hdtv wall mounted to the middle of the front 16' wall with my Magnepans straddling the tv,they're about 8' apart and 3-4' out from the front wall. My listening seat is in the middle of the rear 16' wall. The Magnepans are slightly toed-in and their axis cross at my position.
For serious music listening sessions, I usually move the Magnepans about 5-6' out from the front wall and with no toe-in. I then move my listening seat exactly between them and about 3-6' away from the midpoint between them. I find this positioning allows for an amazingly
three dimensional soundstage illusion on good recordings that is wide, deep, detailed, solid, stable and realistic.
You stated: "To get my former system time-coherent I had to place the Velodyne DD18 a bit in front of the main speakers, if I remember right. Not a good thing, in our living / listening room. Your Debra system seems much more flexible. Happy to hear it works so well. Maybe I could complete my system with half of it - two subs. Although I have neighbours who complain with too much bass."
It makes sense to emphasize the importance of time-coherence of midrange and treble tone frequencies, that is that midrange and treble soundwaves reach the listener at about the same time since these frequencies have soundwaves that are relatively short in length, measured in inches. It makes little sense to include deep bass tone frequencies in this emphasis on the importance of time-coherence, along with midrange and treble tone frequencies, since bass frequencies have soundwaves that are very long, measured in feet. A 20 Hz soundwave is 56 feet long, a 30 Hz is 38 feet long and a 40 Hz soundwave is 28 feet long. Expecting time-coherence of bass, midrange and treble tone frequencies, that is that bass, midrange and treble soundwaves reach the listener at about the same time makes little sense.
Here's a quote from Duke Lejeune, Audio Kinesis owner and maker of the Swarm bass system:
"Another factor is that it takes the
ear a fair amount of time to hear bass
frequencies. The ear cannot even detect the
presence of bass energy from less than one
full cycle, and it takes several cycles to
detect the pitch. So considering the
wavelengths and room dimensions, by the time
we can hear bass tones the room’s effect is
in full swing. Perceptually, in our home
listening rooms there is no such thing as
“direct sound” in the bass region; by the
time we even begin to hear it, it’s all
reverberant sound."
So, moving a sub in front of the main speakers likely makes little to no difference in the perception of bass response performance in a normal sized room.
I believe 2 subs will begin to provide smoother bass response, roughly twice as smooth as a single sub, but that 4 subs will be roughly twice as smooth as 2 subs.
Tim
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Tim, how do you toe-in the Magnepans? Do the speaker axes cross in front of you, at your position, or behind you? I think this matters, also in terms of sub integration. To get my former system time-coherent I had to place the Velodyne DD18 a bit in front of the main speakers, if I remember right. Not a good thing, in our living / listening room. Your Debra system seems much more flexible. Happy to hear it works so well. Maybe I could complete my system with half of it - two subs. Although I have neighbours who complain with too much bass.
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Hi Tim
Optional - exactly. I have followed Romeyn’s advice in my own LCS setup, and 95 percent of it was extremely helpful and good. But at some point, it becomes a matter of individual room integration and also listener preference. I do use phase reversal with one of the LCS speakers, it sounds a bit better than correct phase, but I should probably test this again now that I have changed the toe-in of the main Dream Maker speakers. This is, again, an "optional" issue, to my ears. Some like it when they cross in front, some - like me - prefer a more conventional toe-in where they cross behind me. I mailed Jim Smith (author of Get better sound) about this, since in this book, crossing in front is not recommended, it harms the tonality or harmonics. But he wrote back: It is a matter of preference. |
Hello o_holter,
James Romeyn at Audio Kinesis is the guy who convinced me to give the AK Debra 4-sub DBA system a 28-day free home trial. I started off a big skeptic but, after hearing the bass response in my room and system, I'm now probably one of their biggest proponents. By a wide margin the best bass I've ever experienced in my room and the integration with my large Magnepan panels is absolutely seamless.
I followed the Audio Kinesis Debra sub positioning procedure exactly and it turned out very well. However, their advice was to sequentially reverse the polarity on a sub at a time to determine if it improves overall system bass performance. After spending half a day setting up my DBA system I was a bit tired and wanted to listen to it. I figured I'd get to that step when I could. But that was over 4 years ago and my subs still sound great running in-phase, so I now consider this phase reversal step to be optional.
Tim
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Noble100 - re: debra / swarm system - phase changes. I have found reasons to not always follow Audiokinesis advice "mechanically" - it depends on your room and a bit on your listening tastes also. So I’ve now found that my main Dream Maker speakers - to my ears, in my room - sound better crossed a bit behind me, not in front of me like Audiokinesis advices. In other words, a more conventional speaker setup with less toe-in. This may apply to my use of the LCS effect speakers also. Not sure yet. Based on Audiokinesis philosophy the idea is to spread the reverberant sound around and "decorrelate" it as much as possible. Based on advice from James Romeyn at Audiokinesis, I run the effect speakers so that one channel phase (polarity) is shifted. And some other mods that I am not sure about. The great thing with the Swarm and Debra system - and the Dream Maker / LCS system I have - is that it is very much up to the user. Position the speakers right, in the room, adjust phase / polarity, and the reward will be there.
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Dear all, as stated in a post above, I’ve tried a lot of subs, and gradually gave up on it, preferring another system (main + effect speakers) instead. Why? I worked a lot with sub positioning. Getting the subs and the room to agree. The more that can be done in the analog domain the better. Next, I worked a lot with equalizing and adjusting crossover, especially with the Velodyne DD18, recording in REW, looking at the output, and so on. Eventually, I got bored. +1 to mijostyn, above - "bass is about feeling".
Why did I get bored? Because, with a very good set of tube amps driving big horn speakers, the sub importance declined. I decided that I was willing to live with somewhat diminished below 35 hz frequency, since the rewards in other respects (purity and relaxed natural quality of sound) was greater. To my ears. Listening over several years, in my 20 x 27 feet living / listening room.
.
Why did I say farewell to subs? Was it timing? I don’t think so. I found that the subs usually sounded best when time-aligned, roughly, by positioning them relative to the main speakers. I often ended up with subs and main speakers in a half circle, facing the listening position, or with the subs a bit more forward, to keep up with the front speakers. Was it poor crossover integration? No, I found the best crossover point and slope, and even then, I wasn’t fully satisfied.
Why not? It was the amps in the subs - is my hypothesis number one.
When I got the Velodyne DD18, replacing a pair of more anemic REL subs, I was so glad, I remember saying aloud: "Hello, bassist!" I clearly had more quality sound in the lowest frequencies. But over time, this changed into "Hello, solid-state". Or whatever it was, that disturbed the sound, and made it more tense, with the sub turned on. So to get the purest musical experience I often found myself turning it off. I did not like the "glare" it put into the music, which I associated with solid-state sound.
I am not sure of this hypothesis, maybe it has to do with more conventional problem factors like poor timing or x-over behavior, but I dont think so in my case. It mainly has to do with poor sub amping, compared to the amps driving the main speakers. Especially obvious if you are using top notch tube amps to drive the main speakers, and cheap s-state to drive the sub(s).
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The DD amps are not designed after the Acoustats other than they provide the requisite voltage to the panels. A while back Roger designed a drop in board for the Acoustat amp that used 3 x 6DJ8/6922 for a tube input. IIRC his amps also use this input, but he also designed a different output. The ESL is a single flat panel designed for wider dispersion than other panels of this type. I am not sure of the measurements but it has a small footprint. If I had to guess it is 40" tall by 18" wide. Roger does use the panels and amps in his system with an active crossover and two bass speakers.
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Are the DD amps designed after the Acoustat amps. How tall and wide are the ESLs. Single flat panel? Does he use them himself? |
@bdp, thanks for pointing that out and sorry the mistake. The DD amps are extra. If purchased without the DD amps a separate power supply for the panels is included for use with other amplifiers.
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@clio09, are you sure the $12,000 price is with the d-d amps? I stated that a few months ago in another thread, and you informed me that was incorrect, the $12k was for the panels and subs, the d-d amps were an added-cost option. If the price includes the amps, that is quite the bargain! |
@mijostyn, yes that includes the direct drive amps and bass amp with active crossover. As for why it's not on the website the main reason that Roger doesn't have the time to bother with it.
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Clio for $12,000 as listed on Roger’s web site does that include the amps? Why doesn’t he put a page up for the speakers and all the other neat stuff he makes like the 300 watt mono amps?
Atmasphere, those amps got damn hot. They were also easy to over drive if you did not cross to a sub. They hated doing bass. The best sound I got out of unmodded Acoustats was 2 + 2s driven by KMA 100s. They even did bass! I got rid of Acoustat’s interface and hooked up one huge 1:100 Sowter transformer which is crazy to drive but boy do they sound great. Yes, Soundlab owners love your amps. The question is should I do MA-2s or MA-3s:) |
@clio09, thanks for the correction and clarification. |
@mijostyn I've heard the direct drive version- that speaker never seemed to bring home the bacon the way the one did that was easily driven by the M-60s (which replaced an ARC Classic 60; this was a good 15 years ago).
I wish I knew which model that was as I've heard Acoustats that looked just like it but needed a big amp to make them play. The first time I heard an Acoustat though I was very surprised at how well our amps and the speakers worked together. IMO they worked quite a bit better than the Quads, which at the time were also easy to drive.
By comparison the direct drive model had a bit of a trashy sound on top and we got better bass with the regular speaker (it had no hint of trashiness!). But I think there was a good possibility the power tubes in the direct drive model I heard were simply shot. That was a tricky speaker- you really had to be careful around it due to the very high plate voltage on the power tubes.
Of course I've heard Sound Labs many times. Something like 80% of all our MA-2 amplifier production has gone to Sound Lab owners.
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@bdp24, the Beveridge amps were not Roger's design, only the RM-1, RM-2, and RM-3 which mad up the rest of the components in the Beveridge system which if I recall was the 2SW.
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Music Reference now offers an ESL with the option of a direct-drive (no ESL transformer) OTL power amp. MR's Roger Modjeski designed the same for the original Beveridge, and has custom made some d-d amps for Acoustats. |
Atmasphere, they were an undersung product but the company had trouble finding itself and was trying to be all things to all people. Initially all the Acoustats used a "direct drive" high voltage tube amplifier. The first Model was the "X" It was a beautiful 3 panel speaker with the amp mounted inside a plywood enclosure. Unfortunately it was very colored entirely due to the enclosure. They then moved to the Monitor series both three and four panel versions. It was the Monitor 4 which convinced me that they were on to something. It was with this speaker that I first played around with subwoofers. They then again redesigned the enclosures to make them easier to manufacture. These were called the 1, 2, the 3, the 4 then the 1+1, 2+2, 3+3 and 4+4. They felt their sales were low because people wanted to use their own amps so they came up with a two transformer interface which was relatively easy to drive. There were two versions of this interface. The problem with this was that us audio types preferred the Direct Drive amp. The smaller speakers unaided by a subwoofer were not impressive. But the 2+2 was almost an entirely different animal. Given an amp like the Krell KMA 100 they not only had the magic ESL midrange but killer dynamics. Put them with a subwoofer and all hell broke loose. As big as they are they remain very selfish speakers. Very few 3+3s and 4+4s were made. They were just two big and you had to run two interfaces and two amps with each speaker. The 4+4s were the size of the Soundlabs Majestic 845. The most important item that Acoustat brought to the world was the first totally indestructible electrostatic panel. Quads had given ESLs a bad name because they were very fragile and I think Acoustat suffered because of that. My panels are now 40 years old. The 1/2 life of the plastic used in their construction is 50,000 years. Unless you drive a stake through them they will go on forever. If you have heard any of the larger SoundLabs then you have essentially heard the 2+2 but with a bit more dispersion. Most of these speakers have been cannibalized and the panels beaten up. 2+2s in serviceable condition are hard to find. The Company was eventually sold to David Hafler who went belly up some time later.
Panel speakers have gained more acceptance and I think there is room for a lower cost full range ESL like the 2+2. The individual panels might cost $50 to make if that. The frame maybe $100. The transformer/power supply another $100. $400 all told for a speaker you could sell all day long for $4000.............
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Hello atmasphere,
Thanks for the good info, I learned some good stuff.
Tim
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I wouldn’t even consider a tube amp to power subs due to their generally
low damping factors and their resulting poor ability to firmly control
the movement of dynamic cone drivers, especially the precise starting
and stopping required of larger and heavier bass drivers in subs. Actually this 'precise starting
and stopping required of larger and heavier bass drivers' is a bit of a myth. You can get excellent and natural bass out of a tube amplifier if you set things up right. Our amps go full power to 2Hz so no measurable square wave tilt at 20Hz. So often what causes people to think tube amps don't make good bass is phase shift; if there is a cutoff within 1/10th the lowest frequency to be amplified phase shift will be present. This can cause a lack of impact. FWIW, if you overdamp the speaker it will be less able to play bass impact correctly; no speaker needs more than 20:1 damping factor.@mijostyn Some of those Acoustats were very easy to drive and some weren't. I've never figured out the models, but a customer had a set of M-60s driving Acoustats and the combo was wonderful. The Acoustat was a very nice and IMO an undersung product. |
Clio, Roger is absolutely right. ESLs should not be allowed to go under 100 Hz. To destroy that beautiful mid range with stuff any old crude sub woofer can do is a travesty. |
Tim, If you have been following those of us with panel loudspeakers who have a lot of experience with sub woofers, there is a strong belief that removing the very low bass from this type of speaker decreases distortion and increases power handling. With your speakers that have two crossover points at 500 and 950 Hz the effect will not be as pronounced. Clio and I have no cross overs so the effect is over the entire frequency spectrum. You did not roll off the Maggies at 100 hz so now you have the Maggies and 4 sub woofers competing with each other all out of phase. It should be no surprise that it sounded like garbage. But it is a learning experience and you know for sure that approach will not work:) |
clio09: " @noble100, my speakers are the Model 2, mijostyn has the 2+2. I doubt my speakers go down to 28 Hz, but regardless I am cutting them off at 100 Hz. IIRC I think Duke recommends running the mains full range and set the frequency on the Swarm accordingly. If I am wrong about that I apologize to him in advance. I could run my system that way, but I prefer to follow Roger's method and treat the panels as if they were designed to only go down to 100 Hz. As for your amp, measure it. That will tell you what you need to know." Hello clio09, My mistake. Your Acoustat model two's specs state they go down to 30 Hz, which means our speakers are even more similar in their low frequency limits than I originally thought, 28 Hz for yours and 35 Hz for mine. So, I believe everything I stated in my last post still applies. I know the xover frequency and volume controls and settings are the key adjustments that need to be set properly for my DBA system subs to blend seamlessly with my main speakers. I do use Duke's recommendation of running my mains full range and usually set the xover frequency on the Swarm/Debra accordingly, which in my room and with my speakers seems to be about 45 Hz. I just tried raising my xover to 100 Hz on my system as a test. The most noticeable effect this had was to change my system's normally 3D soundstage imaging into a 2D soundstage image. It flattened out the soundstage similar to the difference between looking at a real life live scene and a video of it. It was much less realistic and enjoyable. I think I know the cause and effect of this change in perception but want to think about it a bit more thoroughly before explaining it in words. In my opinion, the ability of a high quality audio system to create a solid and stable three dimensional soundstage illusion in our rooms through a pair of properly positioned speakers, with the assistance of our brains and a well engineered recording, is one of the most enjoyable experiences to strive for in this hobby. I've discovered that my 4-sub DBA system, by adding the accurate reproduction of the lowest audible bass frequencies it was lacking from about 20-35Hz, significantly enhances this 3D soundstage illusion by causing it to sound even more life-like and palpable. The increased bass detail,the increased bass dynamics and impact that can be felt as well as heard along with this added bass output seamlessly blending with the quality of the rest of the audio spectrum being reproduced by my main speakers also contributes to this realistic portrayal. As I've stated, I'm extremely satisfied with my DBA system's performance and my wife's very pleased with its inconspicuous presence in our living room. I'm not claiming a 4-sub DBA system is superior to a line array bass system in bass performance but it certainly is when judged in the living room inconspicuousness and swimsuit competition stages of the sub system contest. Tim |
Hello khiak,
To see my pm to you do this:
Scroll up to your last post dated 5/29/19.
Click on the red square icon with the "K" in the middle.
Click on the "Marketplace Feedback" tab.
Click on the blue thought bubble icon.
Click on the message from noble100.
Attach your video clip and click 'send' or 'submit'.
If you can't do this for any reason, just post again and I'll reply with my suggestion.
Tim
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@noble100, my speakers are the Model 2, mijostyn has the 2+2. I doubt my speakers go down to 28 Hz, but regardless I am cutting them off at 100 Hz. IIRC I think Duke recommends running the mains full range and set the frequency on the Swarm accordingly. If I am wrong about that I apologize to him in advance. I could run my system that way, but I prefer to follow Roger's method and treat the panels as if they were designed to only go down to 100 Hz.
As for your amp, measure it. That will tell you what you need to know.
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Rix, it is impossible to isolate a driver putting out low bass. The pressure wave itself is what makes the whole house vibrate, not the woofers connection to the house.
clio you want to handle Tim. I'm tired of talking to myself.
millercarbon you just gave some of the worlds finest speaker designers the middle finger. I think you should read acoustics for dummies before you start spouting off about what is or is not possible. |
Hello clio09, I've read about your Acoustat 2+2 electrostatic speakers mainly in the Stereophile review attached below but have never heard them myself. Based on this and their specs I've come to believe we're both looking for similar improvements in our system's bass response, namely a little more deep bass extension and improved deeper bass dynamics and impact. Your Acoustat 2+2 electrostatic panels have a bass extension limit of 28 Hz and my Magnepan 2.7QR planar-magnetic panels have a bass extension limit of 35 Hz. Fairly similar specs that would indicate they both would benefit from a sub system that would provide a little more deep bass extension down to the audible limit of 20 Hz and improved deep bass dynamics and impact. If this is the case, which I know it exactly describes the deep bass I thought was missing in my system, then what is required is a supplemental bass system that provides bass extension down to 20 Hz, has the reserve power to provide life-like bass dynamics and impact that are felt as well as heard along with the bass not being perceived as disconnected, slow and lagging behind the sound from the main speakers. I've found this last quality of providing bass that is detailed, smooth, dynamic and fast enough to blend seamlessly with our detailed, smooth and fast panel speakers is the most difficult but one of the best things a DBA system does. It seems like you're now discovering that a custom bass line array can also seamlessly integrate as well or even better than a DBA. Very interesting to know and I'd like to learn more. Btw, I am using that Dayton class AB kilowatt amp for my swarm. I feel like you're setting me up for something, but I'll bite anyways and ask. Why should I not use it? Thanks, Tim https://www.stereophile.com/content/acoustat-22-loudspeaker |
Hello Tim,
I still do not know how to send the video to you. As so I am not savvy, please take me on a step by step. Thank you.
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Tim, actually clio has a 12 foot wide sub woofer which goes deeper than just a single sub. Remember drivers closer together than 1/2 the wavelength of the highest frequency you want to reproduce act acoustically as one driver. Larger subs will allow you to go deeper as long as the enclosures are appropriately designed. I am not sure were this speed thing came in. Bigger drivers with appropriately sized motors are not slower but as the size and mass of the cone increases they become more difficult to control and keep their motion pistonic. All this is outlined by the driver's parameters which we use to design enclosures. I do not like ported sub woofers. They are more efficient and it is easier to get them to go lower but I have not heard one that to my ear is as accurate as a good sealed driver. The problem with sealed drivers is that you have to force them to go down using equalization and a lot of power. But the drivers we have today can easily handle it and with an amp with DF over 500, using a slightly over sized enclosure (Q around 7) you can get some really amazing bass. I personally see no use for drivers over 12 inches. In either a DBA or linear array system with 4 units you will never run out of drive in anything smaller than 40 X 20 feet especially if you keep the drivers up against a wall or corner.
Clio, I did not know you had an M60. What a tricky guy!. Just remove the Acoustats and put the Quads right down in the same place, same angle. Do both DBA and Linear Array and let us know what you think. The quads are point source which means they will not project power (volume) as well as a linear array. As you move back from the listening position the woofers will become progressively louder than the Quads. Down the block you will just hear the woofers:) As long as things are in balance at the listening position you are in business. Even in a DBA arrangement if you can keep the woofers closer than 5 feet apart that would be a benefit. Other people with lower cross over points could get away with more distance.
The 2+2s are nothing more than stacked 2s without the base. The angle is the same. If you could find another set of 2s you could make 2+2s out of them. I toyed around with the idea of making 3+3s but eventually I will go with Soundlabs. I think what Roger is doing is is rolling off the high frequencies at the outer edge of the Stators to make the panels effectively narrower as the frequency goes up which would increase high frequency dispersion. Making 2s or 2+2s disperse is IMHO fruitless. Just stay in your listening position and enjoy. |
@noble100, The amplifier is the Music Reference RM-200, 100 watts per channel, damping factor of 10, can drive a 2 ohm load (it’s a favorite amp among some of the Martin Logan crowd). The other amps I use are vintage Luxman and Accuphase amps. For solid state I don’t bother with Class D, was never consumed with mega watts, and much prefer a high current Class AB design which is more suited to my needs. Also, the 8" drivers I use don’t need much in the way of damping.
As for my subs being feeble, sure no problem, we all have our opinions. Glad I could amuse you. However, I don’t listen to my music loud, I don’t do HT, and I’m not consumed with the last octave in the bass. As I mentioned, the system was designed by Roger Modjeski and his reputation speaks for itself. The cabinets for the 10" drivers are going to be a unique design and the bass will extend lower, but again, bass has never been the primary focus for me. My set up does exactly what I need it to do and so far it’s doing it better as a line array than the DBA. Although I find both set ups to be very useful in creating smooth, fast, and un-smeared bass.
BTW - I hope you are not using that Dayton Audio kilowatt amp for your swarm.
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clio09,
In my last post I stated I had some comments and questions concerning your last post and your numbered clarifying descriptions of your system and future actions and plans. Here’s your post with my comments and questions added:
"@noble100 if it wasn’t clear let me try to clarify it for you.
1. "I’m building subs with 10" drivers for use as either a DBA or line array. It’s nice to have choices."
I agree, choices and options are nice to have. My four Audio Kinesis Debra DBA subs all have 10" aluminum long-throw drivers. These work well in my DBA system for music and ht, providing sufficient bass that can be felt as well as heard. These subs are ported but come with port plugs if you prefer to use sealed subs which some claim perform better on music.
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My audio enthusiast friend, who assisted me with my DBA setup, and I both agreed that we perceived the bass as very similar whether run as sealed or ported subs on both music and ht content. There was no clear advantage we perceived on music content gained from utilizing the sealed sub configurations with the lone exception being we perceived the bass as slightly more extended running the subs as ported. We were both curious on whether using subs with 12" drivers would allow even further extension of the bass response along with increased dynamics and impact without compromising the excellent speed and resulting seamless integration with the main speakers.
2. My active crossover has LP and HP filters set at 100 Hz. So the HP output sends signals 100 Hz and above to the panels and the LP output sends signals below 100 Hz to the 4 subs. Direct drive amps power the panels, a solid state amp or moderately powered tube amp with good damping powers the subs.
I’m very curious about which moderately powered tube amp with good damping you use to power your subs?
I wouldn’t even consider a tube amp to power subs due to their generally low damping factors and their resulting poor ability to firmly control the movement of dynamic cone drivers, especially the precise starting and stopping required of larger and heavier bass drivers in subs. Solid state class D amps seem to me to be the ideal solution for driving subs; very powerful with extremely low distortion levels, great transient responses and extremely high damping factors that often exceed 1,000. They’re also smaller, lighter, less expensive, require less maintenance, run much cooler and are tremendously more electrically efficient than tube amps.
Sorry, but the use of tube amps to power subs really perplexes me. You must have a good reason you’re not utilizing class D amps, right?
3. My current subs use 8" drivers in a tightly stuffed 0.3 cu. ft. box. This was done to insure the resonance of the driver was above 100 Hz. If I set the crossover points to 150 Hz on my filters this would be an issue but since I’m using 100 Hz and anything below that is sent to the subs this falls below the resonance so it’s a good thing. I should note that this was designed by Roger Modjeski for his ESL speaker system and the subs easily extend down to 30 Hz. If you don’t know who Roger is look him up, his experience and reputation speak for itself.
A sub with a single 8" driver tightly stuffed in a tiny 0.3 cu. ft. box that extends down to only 30 Hz? Can this small creation even be accurately described as a sub? Please excuse me, but as a sub I think this can only be accurately described as pathetic, feeble, impotent and kind of unintentionally funny.
Tim
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I want to add my subwoofer to my stereo system, I run the DAC directly into my amplifier. The Dac has a volume control, and the amplifier is balanced with DB25 connectors with pass-through.
Has anyone had experience here with an output decoupling transformer and summing two channels?
Oh and if you really want to clean up your sub sound, put springs under it.
Yes for real, it stops the vibrations going into the substrate and back up into everything you don't want to vibrate, including the sub woofer that created the vibration.
Townshend Audio in the UK have plenty of scientific style videos showing the benefits of seismic isolation.
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Helloclio09,
My perspective is that the DBA concept is one of several solutions for those looking to add or improve bass response in the 20-200 Hz range in their systems. You're correct that I have a certain devotion to the DBA concept solution. This is probably due to it being the solution I researched the most, the solution I have significant personal experience utilizing in my own system as well as the one that has currently worked the best in my system and room.
I realize my previous experience was limited to experimenting with single and dual sub solutions in my system, but I learned that 1 sub is better than none and that 2 subs are better than 1. Both restricted good bass response to the listening position area and I perceived the bass from both as being slower, lagging behind and disconnected from the rest of the frequency range being reproduced by my fast and detailed Magnepan 2.7QR planar-magnetic speakers. However, I noticed adding a 2nd sub did begin to make the bass seem smoother, a bit faster, less lagging and better integrated with the main speakers along with more impact and better dynamics. With the 4-sub DBA, everything improved significantly. The bass was very detailed, smooth, impactful and dynamic without any sense of lagging behind or being disconnected from the main speakers. Also, this excellent bass response was not limited to just the listening position area, it was equally good throughout my entire 23' x16' x8' room, including from all 6 seating and viewing positions within it.
So, yes I do admit I have a certain devotion to the DBA solution. But I'm not naïve or close-minded enough to believe it's the only or even the best solution. I haven't heard a line array bass solution and would prefer, as you apparently do, to personally experience any and all promising bass system solutions before declaring any particular one the best.
Unfortunately, I'm precluded from personally experiencing a good line array setup in my system due to a lack of a dedicated room and my wife's preference for our living room front wall not resembling the stage at a 9 Inch Nails concert. As all Audiogon Forum regulars know, however, the next best thing to personally building and experiencing a bass line array system for yourself is to listen very closely to the impressions of someone else who has. Which is why I'll be trying to follow your posts on your custom line array system and impressions closely.
I also have some comments and questions concerning your last post and your numbered clarifying descriptions of your system and future actions and plans. But I've blubbered on too long already, so I'll include those in a separate post soon.
Thanks,
Tim
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@mijostyn, I'll have to send you a photo showing what Roger did to create the wider dispersion. It basically involves some resistors, I believe three of them mounted near the bottom of the panel. I had to snip some of the wiring to put them in.
Roger felt that the Model 2, 3, X, and 2 + 2 designs were very good. So in designing his ESL panels he utilized the Acoustat panel material, as well as what he learned from Harold Beveridge and his own research to come up with his design. One thing Roger did not want was a big ESL, so it has a small footprint which means it's not very efficient, maybe 80 dB, and it doesn't go low, 100 Hz. He also did not want to mess with curved panels, so his are flat. His idea was to create a system made for bi-amping using his own direct drive amps and a solid state amp he would design with built in crossover (in our systems we both use the Beveridge RM-3 but given those are pretty unobtanium that would not be feasible for consumer sales). Roger much preferred the subs not be part of the panel structure, so they could be placed around the room, much like a DBA. He uses only 2 in his system.
My Acoustat Model 2s have slightly angled panels, that come to a peak in the front middle of the speaker and angle back from there. The panel sizes are the same as your 2+2 I believe. On each speaker one of the panels was removed and replaced with one of Roger's from an early prototype of his speaker which had the same exact size panel. The other panel is stock. I can set the speakers up so Roger's panel is on the inside or outside (which is how I have it now) and I have definitely noticed a difference in imaging when swapping positions.
As a side note I just got my Atma-Sphere system set up again today and at some point I will probably bring out my Quad ESL 57 to use with the M60 amps. I like this combination as well, although I don't think the line array will work with 57s, so I'll probably go back to a DBA.
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Clio I find your choice of a 4th order cross over at 100 Hz interesting. I can use any slope I want up to 10th order and can change cross overs on the fly. After eons of experimentation I settled on a 6th order low pass and a 4th order high pass all at 125 Hz. This is remarkably close. Is this coincidence or is this great ears hear alike? How did Roger modify the Acoustats for greater dispersion? Did he change the angles of the panels? How does Roger design his ESLs? Sanders uses a flat panel and crosses to a transmission line woofer at 175 Hz. I have not heard them myself. I talked to him via e-mail of doing a 7' 8" panel as a line source and crossing lower at 100 Hz but he was resistant to that idea. ML does the curved panel thing which highly limits their low frequency response to 250 Hz because of non linearities in the curved panel. Soundlabs uses facet panels in a curved array covering either 45 or 90 degrees. Acoustat used two, three or four panel angled arrays depending on the model. Sanders is the most selfish approach his argument being that there is only one listening position and everywhere else is background music. Plus as you increase dispersion you get into more trouble with room acoustics. He is right on both counts but it is nice to be able to provide a balanced frequency response throughout the room even if you can not provide an image especially when theater is concerned. I do not believe 45 degrees of dispersion causes significant problems with room acoustics. |
mijostyn states:
The reason clio is now feeling his bass is because his subs are now functioning as one driver and the arrival time (phase) is the same across the entire room.
This is of course impossible. |
@noble100 if it wasn’t clear let me try to clarify it for you.
1. I’m building subs with 10" drivers for use as either a DBA or line array. It’s nice to have choices.
2. My active crossover has LP and HP filters set at 100 Hz. So the HP output sends signals 100 Hz and above to the panels and the LP output sends signals below 100 Hz to the 4 subs. Direct drive amps power the panels, a solid state amp or moderately powered tube amp with good damping powers the subs.
3. My current subs use 8" drivers in a tightly stuffed 0.3 cu. ft. box. This was done to insure the resonance of the driver was above 100 Hz. If I set the crossover points to 150 Hz on my filters this would be an issue but since I’m using 100 Hz and anything below that is sent to the subs this falls below the resonance so it’s a good thing. I should note that this was designed by Roger Modjeski for his ESL speaker system and the subs easily extend down to 30 Hz. If you don’t know who Roger is look him up, his experience and reputation speak for itself.
I tend to think at this point you just might have an issue with anyone who isn’t completely devoted to the DBA as you are. At least I can say from experience I have used the DBA and now trying a line array I have the ability to compare and decide what works best for me. My comments regarding Duke have more to do with my respect for him as a speaker designer, having owned his speakers at one time and exhibited his speakers at shows, than anything to do with DBA. Anytime I am at an audio show and Duke is exhibiting I make sure to spend time visiting the room. It’s always interesting to see what he is up to.
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clio09:
"My subs were built a while back, mijostyn helped me set them up for optimal performance in the line array. His subs have quite a large footprint, as do his speakers which are probably the best Acoustat model in my opinion. They line array per mijostyn is actually a semi circle as opposed to all of the subs being against the front wall of the room. A very interesting set up and one that does require some attention to detail. I appreciate mijostyn’s patient with me.
In my room the DBA did work well for my needs, and it wasn’t a difficult system to set up. My only nit was that my room constraints didn’t allow me complete freedom to place the subs anywhere I wanted. The sound was quite good though. I am embarking on building 4 new subs using a 10" driver and look forward to going to the audio show in Long Beach to hear Duke’s Swarm in person."
Hello clio09,
I'm having difficulty following along with your posts. From your post quoted above, it seems you're switching from using a distributed bass array (DBA) to a line bass array system for your Acoustats and with mijostyn's help.
Then, in the very next paragraph, you state you're starting to build four new subs with 10" drivers and you're looking forward to hearing Duke's Swarm DBA system, which happens to utilize four subs with 10" drivers just like the four new subs you're about to start to building, at an audio show in Long Beach.
Don't you agree this might be a bit confusing to a reader, especially when you just stated you're in the process of switching from a distributed to a line array bass system?
But the confusion continues with your latest post from5/27/19:
"I use low pass and high pass filters in my active crossover, Linkwitz-Riley 4th order 24 dB slope. One reason this was chosen is that we wanted to keep deep male vocals out of the subs. The other reason had to do with the resonance of the 8" drivers which we wanted to keep above 100 Hz. This is the reason for a 0.3 cu. ft. box which is stuffed tightly with cotton batting. The last reason has more to do with Roger Modjeski’s ESL design which only goes down to 100 Hz but that is irrelevant to me as I use the Acoustats which he modified to create greater dispersion, but left the rest alone, sort of ;)"
Now you're discussing 8" drivers in 0.3 cu. ft. boxes stuffed with cotton batting that only extend down to 100 Hz? Would this even be considered a sub and how are these 'mid-bass woofers' even relevant to either the DBA or the line-array bass system you're using?
Can you please clarify?
Tim
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I use low pass and high pass filters in my active crossover, Linkwitz-Riley 4th order 24 dB slope. One reason this was chosen is that we wanted to keep deep male vocals out of the subs. The other reason had to do with the resonance of the 8" drivers which we wanted to keep above 100 Hz. This is the reason for a 0.3 cu. ft. box which is stuffed tightly with cotton batting. The last reason has more to do with Roger Modjeski’s ESL design which only goes down to 100 Hz but that is irrelevant to me as I use the Acoustats which he modified to create greater dispersion, but left the rest alone, sort of ;)
I should also mention that the speakers are 4 ft. from the wall behind them, 18" from the side walls, and about 94" apart, which is the same distance to my listening position.
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Hello clio09,
Wait a minute. What's your plan?
I thought your plan was switching to a line array with larger subs. Four new subs using 10" drivers sounds like your planning a dba.
Tim
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I forgot to mention that clio has also eliminated 4 of the 5 primary reflections that cause comb filtering in the bass.
Another way to look at this is that the bass linear array is just a more specific DBA system. It will always require 4 or more drivers unless you listen in a closet. |
Thank you clio. You said something that is very important (to me at least)
Bass is not just about hearing. It is about feeling. Part of the rush of a live performance is the visceral sensation you get from accurately projected lower frequencies. This is not easy to do in the home environment. Very few systems do this well but it is vital if you want to feel as if you are at a live performance. Even with string quartets the cellos go low enough to feel to to mention the transients caused by banging and thumping on this that and the other. The "visceral" range is (I'm guessing) from 150 Hz down.
Tim, Magnepans are great speakers. If you remove enough bass from them you can get them as close as 28" to the front wall. Just put some acoustic foam directly behind them. There is this thinking that you have to keep the cross over as low as you can to prevent the woofers from getting up into your mid range. It is easier to blend in with the satellites at higher frequencies and this is particularly true with dipoles which you have just like clio. He crosses over at 100 Hz, not sure about the slope.
Many cross low because they are trying to avoid a high pass filter on the satellites which is also mistaken. Removing the low end from the satellites cleans up the midrange and increases your power handling. You can put a simple 6 db/oct high pass filter on your Maggies simply by putting a cap across the input of your amps the value depending on your input impedance. The equations are on line.
The reason clio is now feeling his bass is because his subs are now functioning as one driver and the arrival time (phase) is the same across the entire room. His Acoustats are now part of that linear array in the crossover zone. He is now getting his bass as one unified whole not the random output of various drivers around the room. Placing speakers around the room will smooth out response variations but because the speakers are more than likely 1/2 wavelength of the highest frequency you want them to carry apart, they are acting as individual drivers and transients are being smeared. This may be another reason DBA people want to stick with lower x-over frequencies. You can put the subs farther apart and get away with it. A SWARM system can work under certain circumstances. Low x-over points in smaller rooms. Once you pull your cross over up and get into a larger room say 15 X 20 you get into trouble.
What you hear is important. But with bass what you feel is more important. |
Hello Tim,
“ I just sent you a personal message. You should see a 'dialogue bubble' icon on the upper-right side of your screen, next to the 'shopping cart' icon. Just click on that and my pm should show. Click on my pm and I think you can hit reply and attach your video clip before sending.
I'll re-post on this thread once I receive it.”
i do do not know where to locate ‘dialogue bubble ‘ icon.
khiak |
My subs were built a while back, mijostyn helped me set them up for optimal performance in the line array. His subs have quite a large footprint, as do his speakers which are probably the best Acoustat model in my opinion. They line array per mijostyn is actually a semi circle as opposed to all of the subs being against the front wall of the room. A very interesting set up and one that does require some attention to detail. I appreciate mijostyn’s patient with me.
In my room the DBA did work well for my needs, and it wasn’t a difficult system to set up. My only nit was that my room constraints didn’t allow me complete freedom to place the subs anywhere I wanted. The sound was quite good though. I am embarking on building 4 new subs using a 10" driver and look forward to going to the audio show in Long Beach to hear Duke’s Swarm in person. |
Hello clio09,
I'm very impressed with mijostyn's linear/line array sub system and I've never even heard one in a home system, although I'd love to.
I'm also very interested in in your bass system build with your Acoustats that mijostyn is very kindly assisting you with. I'm also very happy with my DBA system but would be tempted to try it if I had the clean slate of a dedicated room. My combo music and ht room is also my living room. My 4 subs are currently very inconspicuous in the room which I think is very cool, because you only hear and feel them when there's prominent bass content on music and ht being played, and my wife can live with.
As I understand line array bass systems, the subs would be aligned across the front wall of the room and my 6x2 foot Magnepans would also be positioned about 4-5 feet out from this front wall. I'd be okay with it but my wife's opinion of this in our living room would likely be expressed by a sturdy frying pan smacking my skull.
But I wish you only the best on your build clio09 and hope you and mijostyn enjoy your linear array bass systems very much.
Please do post updates.
Thanks,
Tim
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I have known Duke LeJeune for quite some time now, even owning his Jazz Module speakers for several years and using his speakers in my exhibit rooms at audio shows. Earl Geddes was his mentor and while Duke manufactures box speakers, he has a pretty good understanding of ESLs having used the original Quad ESL in his research (the speaker that replaced my Jazz Modules) and being one of the more prominent Sound Lab dealers. I think he has a good grasp on sound dispersion and how to maximize it. In addition, I should mention I had never been keen on using subs in my system even though I was well aware of Duke's initial work developing the Swarm.
The last show I exhibited at with Roger Modjeski we used his ESL speakers which by default had to have subs since they only went down to 100 Hz. Roger designed a sub with an 8" driver in a 0.3 cu. ft. sealed box (air resistance) and used two to compliment his panels in a bi-amp set up with the Beveridge RM-3 crossover he designed for the 2SW speakers long ago. After hearing this I followed suit but decided I would expand to 4 subs to replicate the DBA of the Swarm. For the last few years I have enjoyed this set up with both the Quad ESL and now my modified Acoustat Model 2 speakers.
However, I was intrigued enough by mijostyn's set up that I contacted him and he sent me a photo so I could visualize it. I would like to add that I was not unhappy with my DBA set up, but since he was also using Acoustats (they are essentially a bigger version of my Model 2s) I felt this was worth a try. Over the past few days we have been communicating and he has helped me tweak things to get the set up just right. I have been listening on and off since last evening and have to say I am impressed by what I hear, the primary difference being what I feel in the low end. So I would like to thank mijostyn for his contributions to this topic and help getting me there. I will try to post more on this as I continue my listening.
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Hello mijostyn,
I’m running all 4 subs in mono with a xover frequency between 40-50 Hz and a filter slope of 12 db/octave, usually configured for a 40 Hz xover for music and 50 Hz for ht. My main speakers are Magnepan 2.7QRs that each have a 620 square inch planar-magnetic dipole bass section but they only extend down to 35 Hz. I run these full range with a pair of D-Sonic M3-600-M mono-blocks rated at 1,200 watts each at 4 ohms. This combo produces very accurate and high quality bass on their own but I added the AK Debra 4-sub DBA system for added bass impact and increased dynamics.
Since the 2 bass sections only extend down to 35 Hz, I don’t consider them extra subs in the room but I do think they help on the overall bass quantity and quality in my room; for example, hearing the initial pluck of an upright bass’s string followed by hearing the deeper bass produced by the body of the instrument and finally the natural decay.
Subjectively, I perceive the bass as very accurate in tone, detailed, extended, dynamic, smooth and natural with an impact that is felt as well as heard. I don’t detect any bass muddiness or have the sense that the bass is too slow, lagging behind or disconnected from the rest of the reproduced spectrum.
However, I’ve never had the in-room frequency response measured but I would be very surprised if it didn’t measure well. I do have pictures of my room and system on my profile if you’d care to look and my room is 23 x 16 feet with 8 foot ceilings.
Thanks,
Tim
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