Front- vs. Down-Firing Subs and Amp Issue


A couple of assertions in the audio world have me perplexed as to how to select a subwoofer for my two-channel system.

Richard Hardesty makes the blanket statement in his Audio Perfectionist Journal that down-firing subs should never be used for high-end two-channel audio. Only front-firing subs are suitable for this application. I see, however, that some of the most-recommended subs on a'gon (Hsu TN series, ACI and REL come to mind) are down-firing (or up-firing in the case of Hsu.) Maybe the answer is that audiophile subs can't be purchased at the price point most mortals can afford, and the lower-priced subs just happen to be down-firing? Oh, Hardesty also says ported subs are not suitable for high-end audio; must go with a sealed box. Interesting.

The second assertion comes from Mike Barnes at nOrh, who says on his website that the plate amps used in 90% of subs today is crap and puts out only a fraction of power that is claimed. The sound that was rattling his windows and creating "earth-shaking bass" was not bass at all- it was distortion. He also states that he began tests in subwoofer development using the popular Peerless 12" woofer, which was literally shredded by a (non-plate) 150-watt amp.

So now I'm confused. Is it possible to buy a high-quality sub for relatively little money? I can't bring myself to spend $3-5k on a pair of speakers only to turn around and spend nearly that much on a sub. Oh, and then I hear that if I want the best possible configuration I need two subs at twice the price, making my subs more expensive than my speakers. Is this just a fact of life that I'll have to come to grips with if I don't want to buy speakers that go down to 20hz?

Thoughts?
aggielaw
"Richard Hardesty makes the blanket statement in his Audio Perfectionist Journal that down-firing subs should never be used for high-end two-channel audio."

I agree...the rest of your speakers are not down-firing are they? The exception may be subs that are used only for 50hz and below...the lower the better.

"The second assertion comes from Mike Barnes at nOrh, who says on his website that the plate amps used in 90% of subs today is crap and puts out only a fraction of power that is claimed".

True, many are rated even higher than my 150lb. Krell...most are junk, I own passive subs and use good amps with them.

There is a new breed of amps that may change some of this so plate sized amps could be the future?...(ICE based and others) of the so called digital types. (do a search here for more info).

Needing or not needing a sub is a factor of many things...tell us more about your room, needs, and components you will use in your system....music types could also play a factor.

Dave
Thanks for the insight, Dave. A link to my system is: http://forum.audiogon.com/cgi-bin/fr.pl?vdone&1107477492&view

I have a Velodyne CT-120 sub in the system, which I think is not listed in the thread above. It sounds nice, but I keep wondering if it could sound better.

My room is approximately 11'x17'x8', set up on short wall. Acoustically, it's a nightmare, with a cinderblock exterior wall with large windows on the right and an open wall starting at 3' in front of the left speaker on the left. The front and rear walls are wood. There's an exterior door on the right wall toward the back, so the listening position is 4' from the back wall.

Music tastes are primarily progressive rock, soft rock, and jazz (I'm a big Chuck Mangione fan and like other upbeat jazz as well) with a bit of country and "world music" for want of a better description. Occasionally I listen to classical, but not as often as the other genres listed.

Thanks,
Howard
If we limit the discussion to true subwoofers as opposed to add-on woofers, then there is absolutely no problem with down firing subwoofers. For instance REL touts their 2 channel oriented subwoofers as sub-bass systems. They are specifically designed to add not bass, but deep bass to existing full range speakers. A down facing driver is an excellent solution for such a situation.

Regarding subwoofer amps, it's just like anything else, some are crap some aren't. A dedicated sub amp doesn't have to be the most refined amp because it's only handling low frequencies where harmonic distortion is harder to hear and less offensive.

My experience is that two subs are better than one, but one great sub is better than two good subs.

Earlier today I saw that someone was selling a Monitor Audio sub for less than $500. They are great subs for music. BTW, they have both forward and down facing drivers.

What do you think of the Norhs?
Onhwy61, besides REL, who else makes sub-bass systems, do you know? Vandersteen? I have full range drivers and a very, very budget subwoofer that I place behind my listening chair. It is crossed over at 40hz and it doesn't have much on volume. All it does it give anything below 40hz added weight. Most bass that I want comes from my full rnage mains, but sometimes they lack the grunt I want. The sub behind my chair gives it a tiny push.
to get deep bass - you have to have a listening room big enough to support it...

btw, i recently picked up a rel for my surround system and i am breaking it in my 2 channel system (dedicated room)..

i can say the rel starta III ($1700) is good enough to use with my full range ap libra ($8k) and my classe cam mono 350's....the libra's are rated down to 27 hz...

there is something about adding a sub....it actually improved the imaging and smooth out the bass response.. in short, the down firing rel is a very effective accoustic treatment...
The statement that no down firing sub can sound good is just stupid, if it is sealed, then what the hell does it matter where it fires, but I agree sealed is the way to go.
Ever wonder how they term "sub" woofer ended up being so loosely used, the word "sub" used to have meaning...now you can buy subs that dont even go down to 20 cycles, what is "sub" about that?
Aren't those PartsExpress.com, Daytona, Titanic DIY subs sealed? I heard these subs are really good, especially for the money. I want one. The thing is, I already have two other subs. What does a person do with overflow subs?
Matchstikman, Audio Physics also makes sub-bass systems.
Hey match, a person with over-flow subs gives them to me lol
Muse model 18. One of the best ever made.
Dear Howard: First than all: congratulations for your North great speakers.

+++++ " Is it possible to buy a high-quality sub for relatively little money? I can't bring myself to spend $3-5k on a pair of speakers only to turn around and spend nearly that much on a sub. " +++++

The task that have a subwoofer is the most difficult area in the home audio frecuency spectrum ( from 80Hz down flat to 16-20Hz ) sound reproduction. So ,you can't expect that that " very hard task " is for a " little money ", at least not for a good quality sound reproduction.
If the task of low/deep bass reproduction were an " easy " one then the subs does not exist because any builder/designer of speakers could incorporate in their full rage speakers and for a low price. If you take a look to the price of full-range speakers ( 20Hz to 25kHz ) you can " see " that everyone had a very very high price. Much of that high price has to be with the quality reproduction of the last two octaves in the music.

Now, yours North speakers deserves something, at least, at the same quality sound reproduction level: not less. Well this is my opinion.

I agree with the people that is in favor of the sealed subs and agree, too, with the people that is in favor of two subwoofers instead only one.

I'm in favor, too, of self-powered subwoofers instead the passive ones. The self-powered subwoofers have many advantages against the passive ones.

Now the issue of down firing against the front ones it is not important in sealed subs.

Now, your main speakers needs a " true stereo " ( a pair of subs )integration subwoofers. The REL ones are not a good option for you: the REL design is for " bass reinforcement " on true full-range speakers or for HT, not for a true stereo configuration with monitors liker yours.

Now, the assumption that the subwoofers objective is to enhance the low bass reproduction is a misunderstood about. The integration on a true stereo fashion of two subwoofers in any system has to be more with obtain not only a better quality low bass reproduction but: better mid bass, better mid range and better high frecuency reproduction.

Please if you have the time read very carefully these links:

http://forum.audiogon.com/cgi-bin/fr.pl?eanlg&1117893153&openflup&27&4#27

http://forum.audiogon.com/cgi-bin/fr.pl?eanlg&1117893153&openflup&31&4#31

+++++ " 50hz and below...the lower the better. " +++++

+++++ " many are rated even higher than my 150lb. Krell..." +++++

Dave, if you can read those links about.
Btw, of course that many of today subwoofers are rated much higher than your Krell amp, but the task of your Krell is very different that the one of the sub-amp: you can't compare it, the 150lb means nothing in this subject.

Regards and enjoy the music.
Raul.
I have a Velodyne CT100 in my system...i think that i could do alot better personally...just my 2c
All of the above comments have merit. It will depend on your room. My down-firing REL reinforces my two channel monitors but is crossed-over at 40 Hz and is sealed. It has a "presence" in the room and is necessary for realistic reproduction of music, but not for movies. I have a Hsu VTF-3R Mark 2 and it doubles for movies (crossed at 60 Hz even with floorstanders) and music. It is hardly on for music but fills in a little at the bottom. It is a compromise and better with movies. I recommend REL for adding bottom to 2 channel. My opinion: a subwoofer should be front firing if it is crossed over high enough to localize (60 Hz, 80 Hz, 100 Hz?) and then should be placed in front between the mains. An advantage of the mail-order companies is trying them in your own home and seeing how it fits. Also, 2 subs are twice the challenge of 1 in terms of set-up. Good luck!
Raul said,

"
The task that have a subwoofer is the most difficult area in the home audio frecuency spectrum ( from 80Hz down flat to 16-20Hz ) sound reproduction. So ,you can't expect that that " very hard task " is for a " little money ", at least not for a good quality sound reproduction.
If the task of low/deep bass reproduction were an " easy " one then the subs does not exist because any builder/designer of speakers could incorporate in their full rage speakers and for a low price. If you take a look to the price of full-range speakers ( 20Hz to 25kHz ) you can " see " that everyone had a very very high price. Much of that high price has to be with the quality reproduction of the last two octaves in the music".

Humm, and you think cheap plate amps are best up to this task?.

"I'm in favor, too, of self-powered subwoofers instead the passive ones. The self-powered subwoofers have many advantages against the passive ones."

Not really, unless were talking price and convenience...no advantage in sound quality at all IMO as all the convenience features can be had out-board, and as high, or higher quality to boot.

Some of the new wave of subs hitting the market may change this as that technology filters down into lower price ranges but for now these subs are big $$$ and out of the price range of most IMO.

BTW, I use three subs, one off of my prepro's LFE output and the other two with outboard x-over...works for me.

Dave
I use a Polk vented dual side firing 12 inch for movies- great for explosions but not for music. Its slow, soft mushy but it can move the couch. For music, an active xover feeding separate bass boxes- dual front firing sealed 10 inch Hale woofers driven by a modded BK 442 amp. I set the cross over way up their at 120hz-trial and error route. The bass amp runs very very hot, it gets a workout. Best test is Bach Cello Sonatas - it reproduces that wonderful cello bass sonority that you can hear and even feel where the vented sub seemed to just buzz. Best is front firing with a nice transisiton to higher frequencies.
Dear Dave: +++++ " Not really, unless were talking price and convenience...no advantage in sound quality at all " +++++

I think that this statement is a misunderstood about the subwoofer subject. This is what I already post on other thread and, by coincidence, what the Audio Perfectionist Journal review about:

+++++ " - Now the low bass frecuencies are handle for a dedicated driver that was build with specifics characteristics for to work in that frecuency range and this low bass driver is matched with an amplifier ( self powered subwoofers ) that was build with specifications that mates excatly what the low bass drivers needs about: frecuency response, output impedance, damping, power, etc..... You can't ask for more!!! " +++++

The concept of passive subwoofers, the use of only one ( mono ) sub and low bass enhanced through a subwoofer is a very " old " concept that already change, for the better, for the new concept: integration of subwoofers in a true stereo way, with all the advantages that these means ( read carefully those links ).

Regards and enjoy the music.
Raul.
Dear Tgrisham: +++++ " a subwoofer should be front firing if it is crossed over high enough to localize (60 Hz, 80 Hz, 100 Hz?) and then should be placed in front between the mains.. " +++++

You can't localize where are the subs at a crossover point from 80Hz and down. You can try and you will see that it is almost impossible.
The position of the subs has nothing to do if is front/rear/down firing, the room position is a very complex subject where there are no absolute rules.

You can read the links that I already post in this thread ( the first post ) about the whole subwoofer concept. Maybe these links can help you to obtain a better quality music reproduction from your system.

Regards and enjoy the music.
Raul.
Rauliruegas,

I understand the concepts. I too believe that 80 Hz is the limit for localization of low frequencies, but others disagree. Below 80 is not a problem, above 80 can be. Bass frequencies have such long wavelengths that the position of the sub has more to do with modes and room interactions, unless the crossover is high. If the sub can be localized due to the higher frequencies it produces, then it should be placed near the front speakers. This will minimize the confusion created by various sound sources arriving at different times. In an ideal world we would have speakers flat from 10 Hz to 30k Hz and subs would not be as important. As such, I believe that subs are important. Implementing them in a given room is the challenge and I have only been successful through trial and error. I tried the formulas and gave up! The key is to continue to have fun, not take it too seriously and experiment. And, I agree, its only about the music.
Dear Tgrisham: I agree with you..

Regards and enjoy the music.
Raul.
Hmmm. while not a sub my Dunlavy Athenas have a downward firing 10 that is rated flat to at least 30 hz and lower with room effects considered. the bass is extreemly tight and musical. I spent a lot of time dialing the speaker position in to get everything balanced and i stronly agree with the fact that just throwing a sub into a room and hoping for the best won't work.

Tgrisham, for pro soundsystem application we have the subs located below the mid/high tops,corssed over at 100hz and there is no +difficulty with two subs vrs one. I would thnink that home set ups should be similiar as long as you keep the speaker locations matched up and not scattered all over the room so each box is fighting a different room condition.
Chadnliz, my "overflow" subs aren't worth much. All of them are low-budget and have been modified by moi in an attempt to make something budget sound a little better.
You are right Piezo. I agree about two subs instead only one. As a fact we can have less room-problems with two subs against only one.

Regards and enjoy the music.
Raul.
So what? Front or down firing? Or as with everything else in audio, whatever you like is best?
Dear Matchstikman: I think that the sealed vs vented design is a more important issue and here I think that sealed is the better way to go.

The down vs front subs is more a builder design choose. If the subs are sealed it does not matters the down vs front firing debate.

Now, for any one can choose subwoofers: the best way to do is testing at home because the sub interaction with the room and the main speakers is critical. If we can't do that then we have to go for a confident/experienced subwoofer manufacturer like Velodyne, Aerial, Rel, etc...

Regards and enjoy the music.
Raul.
I don't understand what people have against vented subwoofer designs. I am currently running REL Stadiums and I don't hear any problems.
Ok, help out a guy that doesn't know; what is the argument against vented subwoofer designs?
Well, my subs use 15"/12" active along with a 15" passive...I guess that puts them in the vented camp and I don't hear any problems...but, this is what Sean had to say in another post regarding the advantages of a sealed sub:

"The one advantage that vented designs offer is that they will play louder. Since this is not a major concern of yours, you can take major advantage of the improved transient response, increased damping, lack of overhang and ringing, slower resonance, more controlled output at resonance, etc.... of a sealed box. You'll also get less "bloat", which means you probably won't annoy the neighbors as much".

Sounds like sealed may have the upper hand?

Dave
If sealed has the upper hand, why aren't more subs sealed?
Probably because most only think of subs as movie rumble boxes. Some do not take the time to hear the difference in a sealed or ported design. I like ported subs but only for Home Theater...where high spl is needed. This hobby has a very small community compared to the average consumer looking for boom and rumble.
"If sealed has the upper hand, why aren't more subs sealed?"

Well, I don't know...what is the ratio between the two types? Also, when he says ported will play louder...I'm wondering if he means (louder with less power needed) and not louder overall.

Dave
If you run a vented sub,the designer knows that you can get away with a smaller enclosure.If you offer a sealed enclosure(arguably more "pitch accurate",and correctly so)you need more internal volume,and a larger box.That is why we don't see many sealed enclosures,in subs and regular speakers!!It is our loss!!However we,ALL,have allowed the market to shift in this direction,due to ergonomic considerations.
If I understand Sean's arguments correctly it's that sealed designs have potentially better..., but in the real world is that potential always met? Sean is not saying you can't design a vented sub with all those good characteristics, just that a sealed designed can do the same easier. The fact that the sub is the size of a large refrigerator is not important since we're audiophiles only concerned about sound quality. And remember, two refrigerators, I mean subs, are better than one.
The arguments against down-firing subs that I've seen revolve around gravity's effects on the woofer. I've never heard a down-firing sub, so I don't have any personal basis to compare the two types.

I couldn't find Hardesty's assertion that front-firing is better, and he has a hard-on for all things Vandersteen. From the photo on the Vandersteen website, it looks like their subs are down-firing. Interesting.

The consensus that sealed subs are more tonally accurate than vented subs makes me wonder: is this premise true of woofer-handled frequencies as well? Is it important to have sealed towers or monitors as opposed to vented models for accuracy?

I don't have any answers, but the great responses I'm reading are making me alot smarter so far!
What about horn or horn-like subwoofers like this one:

http://www.decware.com/WO32/wo32.htm
Dear Onhwy61: +++++ " it's that sealed designs have potentially better..., but in the real world is that potential always met? " +++++

This depend on the design and the execution of that sealed design.
The " sealed design " can't warranty: " per se " that that particular sealed subwoofer is a good performer or that can be better than a vented one.
There are bad sealed subs, as I told you this dependes on the exellence of the builder and the excellence in the execution of that design.

Regards and enjoy the music.
Raul.
Dear Aggielaw: +++++ " Is it important to have sealed towers or monitors as opposed to vented models for accuracy? " +++++

Yes, it is important. But here the manufacturer has a problem: how to build a monitor in a sealed small box with good " bass " down to 30/35Hz?

He can do it with a vented design or he can do it in a sealed design with a bigger box, of course there are other alternatives ( but we are talking here about vented/sealed designs ).

Now, it is possible that every thing the same: the sealed design can be more accurate and " easy " to the room that a vented one.
Now, one issue that is important to these two designs is at what volume/level you want to hear your music. If we are talking of 95 to 105 db SPL then ( probably ) the vented design will be in " problems ", but if we are talking of SPL between 70-85 db we can have the same quality music reproduction from either design.

Regards and enjoy the music.
Raul.
Raul, do you have a list of sealed subs that you think are not as good as they should be? It would be nice to know.
Dear Matchstikman : The horn subwoofers can be really great, the problem is that for a horn sub can handle the normal sub frecuency range: 100Hz down to 18Hz +.- 3db, it has to be enormous and very hard to match with a normal room size .

The ones that you mentioned there are no true subs: they go down only at 28Hz.

Regards and enjoy the music.
Raul.
Dear Matchstikman: No, I don't. I don't have the opportunity to heard all the sealed subs that exist out there.

I own Velodyne's ( great performers ), but I hear: Paradigm, Talon, Vandersteen, Bagend, Dali, Sunfire. From these I don't like ( for music two channels aplication ) the Sunfire and the Dali, this one because it is not a true sub: it only goes down ( I think ) 25Hz. I heard others one but I can't remember if there were sealed.

Regards and enjoy the music.
Raul.
How low must it go for proper music duplication? A low E on a bass goes down to 42hz. How low does a bass drum go for proper reproduction. A pipe organ can probably go very, very low, but I don't listen to much pipe organ.
I have a Hsu VTF2MK sub, 10" down firing w/ rear dual ports. According the to the manual, if I want to play loud, dual ports need to be opened. If I want deep bass, one port needs to be plugged up.
Back to the point, I guess that seal sub can achieve lower frequency than vented ports, given the driver size, the amplifier, the box dimension, and all else are the same. However, there are many variables in real life. This is only my 2c thought, and my HT setup is a 5.2.
Unless you listen too pipe organ music. A sub that reaches into the mid 20 hz region would satisfy most. As someone has stated earlier..the room does play a factor in extention. I use dual stereo 12 inch subs and have measured flat to 30 hz easily in my room at 70 to 75 dB. Meaning I still get down to 20 hz minus maybe a few dB without touching the volume knob.

I would imagine, most instrumental recordings don't get much lower than 35 to 40 hz on average. The woofers excursion plays a roll as well in frequency extention.The Adire XBL and Shiva drivers are some of the best around. Acoustic Vision subs. I'm willing to bet any one of these units will meet or exceed any boutique brand out there in overall performance. It's up to you if you want to pay the boutique prices. Look closely and you will notice the same parts used between these two companies.Just different finishes and cabinet thickness. Adire Rava II.
If the sealed cabinet design doesn't guarantee better performance, than why make the blanket statement that it's so important?
LOL.....1001 reasons hi-fi is great
Back to the original point....it is personal preference. Money doesn't guarantee performance. Listen to as many subs as possible, in your own room if possible. My opinion is this: I have enjoyed my 2 channel more with a sealed REL and my movies and DVD concerts more with a vented VTF-3R Mark 2 Hsu sub. Good luck!
Aggielaw: And back to the original post, ...Where does R. Hardesty states the quote you wrote "that down-firing subs should never be used for high-end two channel audio..Only front firing subs are suitable for this application". I tried to find that quote in the apj free downloads and all i could find its that he really raves and uses in his system the Vandersteen 2wq,...i,m curious to hear more about. regards, Carlos