What's the best subwoofer? REL? JL AUDIO? Velodyne? Wilson? Something else?

Duke LeJeune

[Industry Expert]/Member Sponsor
Jul 22, 2013
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#81
The BEST subs will always be those you build yourself however.
Not only will they be the best, but the most fun! My brother built a pair of 120 dB @ 14 Hz subs into the space under the raised second row of seats in his home theater system. You can't walk into ye olde stereo shoppe and walk out with something like that, and they are uniquely his take on the best solution for his situation.
 

bonzo75

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Feb 26, 2014
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#82
Do you have experience of using Dirac, Trinnov, DeqX or some such stuff for crossing over to subs? So does this work with planars, to use, say, a Dirac box and crossover to a Seaton or JL or your subs? Which Seaton model or Jl model do you recommend. Do you have a pic of your subs?
 

Duke LeJeune

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Jul 22, 2013
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#83
Do you have experience of using Dirac, Trinnov, DeqX or some such stuff for crossing over to subs?
So far I have only used the crossover in the external amplifier that drives all four subs. It has the features I have needed thus far to get a good blend, but I would not be surprised if a good DSP crossover made a nice improvement. My Swarm system is rather modest in price relative to the DEQX and Trinnov processors, so those pairings are probably unlikely to happen.

I build a few speaker systems that are designed specifically to be used with the Swarm. Truly transparent high-pass filters for rolling off the bottom end of the mains being somewhat hard to come by, I design my mains to be run full-range, with no protective filtering. They don't have to be run that way, but at least my customers have the option.

So does this work with planars, to use, say, a Dirac box and crossover to a Seaton or JL or your subs?
Dirac is a PC-based system, is that correct? It looks vastly more affordable than the Trinnov and DEQX processors I looked at. I'm sure that it would work quite well, though I haven't used it.

One thing you want to keep in mind with a distributed multisub system: You want a fairly aggressive low-pass filter on the subwoofers so that subs positioned well away from the main speakers do not betray their presence by passing lower midrange energy at an audible level.

Which Seaton model or Jl model do you recommend.
I don't know whether I've ever heard it (might have at an audio show), but the opposing-woofer version of the Seaton Submersive looks very good to me on paper. I estimate that one of them has about 3 dB more output at 20 Hz than my entire four-piece system. If I used a more powerful amp, I could probably close that gap, but so far no one has asked me to (my woofers have sufficient thermal and mechanical power handling for one kilowatt per sub, if you're careful; I'm only feeding them 250 watts each). I like the idea of using a big box for subwoofage, like the Seatons do, because air is a fairly non-linear spring so the bigger the box the better, all else being equal.

Do you have a pic of your subs?
This is the side that you normally see:



And, this is the side that faces the wall:



That's a ten-inch woofer. The port is down-firing, and the input terminals are on the bottom too.
 
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Enoch Root

Well-Known Member
Oct 8, 2014
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Tiverton, RI
#84
Duke,

First, thanks for your input!

Now a couple of questions, if I may:

Swarm appears to be mono. Can it be stereo?

Also, your information seems to minimize the importance of group delay, yet another experienced individual affiliated with JL Audio insists that consideration of group delay is paramount. Would you address this further?

Thanks again.
 

bonzo75

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Feb 26, 2014
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#85
They look great. I guess since they are downward firing it doesn't matter if they face the wall or not? Do you keep them all together, or in different corners?
 
Jun 5, 2012
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#86
The only subwoofer i would mate with a panel is this one another panel.:)

infraplanar1.jpg
 

Duke LeJeune

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Jul 22, 2013
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#87
Swarm appears to be mono. Can it be stereo?
Yes, absolutely! You'd need to add a second amplifier, and drive the subs on one side of the room with one amp, and on the other with the other.

Now my understanding is that very, very few recordings have stereo information below 80-100 Hz or so. But there is still an improvement to be had from adding that second amplifier. David Griesinger, inventor of the Lexicon processor, recommends locating subs to the left and right of the listening area and adjusting their relative phases so that they are 90 degrees apart (in "phase quadrature"). He reports that this significantly enhances the sense of spaciousness and envelopment, and I agree. Robert Greene also found this technique to work well when he had the Swarm for his review.

Also, your information seems to minimize the importance of group delay, yet another experienced individual affiliated with JL Audio insists that consideration of group delay is paramount. Would you address this further?
In one of the studies I read in the Journal of the Audio Engineering Society, the researchers digitally synthesized group delay independent of frequency response, and specifically looked at group delay times comparable to what one would find in a vented box loudspeaker system. My recollection is that group delay was detectable but not by much on test tones, and effectively undetectable on music program material.

It would take me a while to dig up my source (might have been the same study though I think it was something else), but I recall reading that the audibility threshold for group delay is approximately 1/F, where F = the frequency. The Swarm's group delay peaks at 17 Hz, at a calculated 38 milliseconds. The calculated detection threshold at that frequency is 1/17Hz = 58 milliseconds. So we're well under the detection threshold, and besides 17 Hz is hard to hear. At the normally accepted lower limit of human hearing, 20 Hz, the detection threshold is 50 milliseconds, and the Swarm has 31 milliseconds of group delay. Above 30 Hz, our group delay is comparable to that of a sealed box.

So while there probably are vented systems where group delay is an audible problem, apparently it's not with my particular design. Obviously I believe there are other issues that matter more, in particular, large and highly detectable room-interaction peaks and dips.

While many of the criticisms leveled at vented box systems are technically valid (group delay, degraded transient response, pitch shift towards the tuning frequency as nearby notes decay, possible introduction of various non-linearities, excessive excursion below the tuning frequency), the critics often look at worse-case scenarios. The effects of these issues can often be brought below the level of audibility by careful design, and in practice they often do not start out as significant as our intuition would lead us to believe.

You see, the steady-state condition dominates perception at bass frequencies, because the ear's time-domain resolution is so poor. We cannot even detect the presence of bass energy from less than one wavelength, and we must hear several cycles before we begin to detect pitch. The steady-state frequency response tells us pretty much everything we need to know about the bass region (for example steady-state peaks correlate with slow decay, and the remedy is to smooth them out, which corrects their decay time as well).

Put another way, from a perceptual standpoint, there is no such thing as "first arrival sound" in the low bass region, at least not in the size rooms we have in our homes. By the time we hear low bass energy, it has reflected off of room boundaries many times. So while the difference in transient response between sealed and vented enclosures is certainly there, in and of itself, I really am not sure that it's perceptually significant. But I am quite confident that the in-room frequency response is perceptually significant.

That being said, I might be dead wrong about the audibility of group delay! Group delay (or other vented box problems) might matter far more than I've conceded here. Just so happens, that's covered too: You can plug the ports in the Swarm modules, converting them into Qtc = .5 sealed boxes which will have excellent transient response. The plugs I use were designed for plumbing, so they have no problem with the pressure differentials of a sealed subwoofer. Plugging the ports may result in insufficient low-bass authority, so to offset that, you can engage the bass boost switch on the back of the amp, which boosts the 25 Hz region by 6 dB. If this proves to be too much bass boost, reverse the polarity of one of the subs. If it's still too much, unplug the port of the reversed sub. And so on.

You have probably gathered by now that the Swarm has a lot of degrees of freedom as far as tweaking for best performance. In my open-floor-plan living room, I tried a number of different configurations and all ports open with one sub in reverse polarity seemed to work the best. There is no reason why you can't mix and match sealed and ported Swarm modules, in and out of normal polarity, with or without bass boost or parametric EQ, and just go with what works best for you.

In sealed-box mode, I think the combined output of my four subs would be comparable to that of some ballpark-dollar-equivalent compact sealed "ubersubs"... my combined four cubic feet of internal volume plus four cones and four motors helps make up for not having a 2" excursion megawattage uberwoofer. Where the Seatons beat me in output is, having two 15" uberwoofers in 4+ cubic feet driven by 4 kilowatts, if I understand correctly. They really are a terrific value, and I've heard Mark's full-range speakers, and in my opinion he's a superb designer.

The reasons I use a vented box as the default configuration for the Swarm are: 1) we can achieve my "room gain compensation" target response without EQ; and 2) we get 6 dB more output at 20 Hz than in sealed box mode essentially "for free", assuming I did my job as far as keeping the problems inherent in vented boxes below their audibility thresholds.

* * * *
Someone sent me a message, probably earlier today, but somehow I lost it right after I clicked on it and before I could read it, and now I can't find it. Whoever that was, could you re-send? Thanks!
 
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Duke LeJeune

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Jul 22, 2013
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#88
They look great. I guess since they are downward firing it doesn't matter if they face the wall or not? Do you keep them all together, or in different corners?
The idea was for the woofer to face the wall, so that they'd basically just look like blocks of wood, and that would also save the added expense of a grille. This probably isn't really practical for subs with built-in amplification, so I figured I'd take advantage of it.

As for positioning... well, one in each corner would give the loudest bass of a distributed subwoofer system, but it would be far from the smoothest, so it's not what I recommend for high-end audio.

There are two basic schools of thought on the subject of positioning: Symmetrical and asymmetrical. Briefly, the smoothest symmetrical layout would be each of the four subs 1/4 the way out from each of the walls that meet in a given corner. So if the room is 16 feet by 24 feet, each sub would be 4 feet from the long wall and 6 feet from the short wall. The smoothest "practical" symmetrical layout would be each sub along a wall, at the midpoint.

Asymmetrical layouts are limited only by your imagination and practicality. The general principle is, you want them far apart, but somewhat irregularly positioned relative to the room boundaries. If possible, place one in a corner (because that location drives the most room modes), but no more than one. Here's a very deliberate asymmetrical layout based on golden ratios, in our hypothetical 16 by 24 foot room, assuming the mains are along a short wall:

First sub, right front corner. Second sub, .62 x 24 = 14.9 feet away, along the right wall. This is also 9.1 feet from the right rear corner. Third sub, .62 x 9.1 = 5.6 feet from the left rear corner. Fourth sub, .62 x 5.6 = 3.5 feet from the left front corner. If possible, elevate one of the subs so that it's closer to the ceiling than to the floor.

And at the other end of the scale, just find four places where your wife will let you put a sub, and put them there!

So which general strategy is best? I can't say for sure. In my experience, symmetrical layouts are seldom practical because of doorways or furniture or whatever. And at low frequencies, most rooms' effective acoustic dimensions are different from their physical dimensions. This is because any significant change in the rigidity of the room boundaries (due to a door, entryway, window, closet, or HVAC duct) will change the effective acoustic dimension(s) of the room, and if you have a room with none of these features, it will be difficult to enter. So in practice, a physically symmetrical layout is probably not acoustically symmetrical at low frequencies. Likewise, the above golden-ratio physically asymmetrical configuration isn't going to be golden-ratio acoustically.

The only subwoofer i would mate with a panel is this one another panel.:)

View attachment 19360
Wow, that's beautiful! What is it??

I'm not about to try to change your mind. Is that a bed off to the left? If so, I like the way you decorate a bedroom!
 
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Jun 5, 2012
847
3
0
75
Quebec Canada
#89
The idea was for the woofer to face the wall, so that they'd basically just look like blocks of wood, and that would also save the added expense of a grille. This probably isn't really practical for subs with built-in amplification, so I figured I'd take advantage of it.

As for positioning... well, one in each corner would give the loudest bass of a distributed subwoofer system, but it would be far from the smoothest, so it's not what I recommend for high-end audio.

There are two basic schools of thought on the subject of positioning: Symmetrical and asymmetrical. Briefly, the smoothest symmetrical layout would be each of the four subs 1/4 the way out from each of the walls that meet in a given corner. So if the room is 16 feet by 24 feet, each sub would be 4 feet from the long wall and 6 feet from the short wall. The smoothest "practical" symmetrical layout would be each sub along a wall, at the midpoint.

Asymmetrical layouts are limited only by your imagination and practicality. The general principle is, you want them far apart, but somewhat irregularly positioned relative to the room boundaries. If possible, place one in a corner (because that location drives the most room modes), but no more than one. Here's a very deliberate asymmetrical layout based on golden ratios, in our hypothetical 16 by 24 foot room, assuming the mains are along a short wall:

First sub, right front corner. Second sub, .62 x 24 = 14.9 feet away, along the right wall. This is also 9.1 feet from the right rear corner. Third sub, .62 x 9.1 = 5.6 feet from the left rear corner. Fourth sub, .62 x 5.6 = 3.5 feet from the left front corner. If possible, elevate one of the subs so that it's closer to the ceiling than to the floor.

And at the other end of the scale, just find four places where your wife will let you put a sub, and put them there!

So which general strategy is best? I can't say for sure. In my experience, symmetrical layouts are seldom practical because of doorways or furniture or whatever. And at low frequencies, most rooms' effective acoustic dimensions are different from their physical dimensions. This is because any significant change in the rigidity of the room boundaries (due to a door, entryway, window, closet, or HVAC duct) will change the effective acoustic dimension(s) of the room, and if you have a room with none of these features, it will be difficult to enter. So in practice, a physically symmetrical layout is probably not acoustically symmetrical at low frequencies. Likewise, the above golden-ratio physically asymmetrical configuration isn't going to be golden-ratio acoustically.



Wow, that's beautiful! What is it??

I'm not about to try to change your mind. Is that a bed off to the left? If so, I like the way you decorate a bedroom!
Those are subwoofers from a french designer named Claude Lacroix his website is www.infraplanar.com

http://infraplanar.free.fr/grand infraplanar_fichiers/image004.jpg
 
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Duke LeJeune

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Jul 22, 2013
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Princeton, Texas
#90

caesar

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May 31, 2010
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#91
Seems like the "audio journalists" have mostly been acting as marketing representatives for JL Audio subs over the last 3-4 years...

Looks like REL has a new reference sub, called No .25 It's powered by class D amplification, vs. the lower models being powered by AB. It looks beautiful, in part to impress the wives. It has a much more powerful power supply than the other models, but only goes down to 14 Hz vs. previous reference model of 15 Hz (-6db).

Anyone have any thoughts?
 

Ron Resnick

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#92
Actually I think the true prior REL reference -- the Studio III -- was -6dB at 9 Hz.
 

SCAudiophile

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Sep 11, 2010
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#93
Actually I think the true prior REL reference -- the Studio III -- was -6dB at 9 Hz.
yes...that's what I remember as well; any luck finding a pair of these or have you determined what (other) sub will be in the system you are building up to Ron?
 

Lagonda

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#94
My favorite subwoofers!
IMG_0792.JPG
 

16hz lover

Well-Known Member
Aug 2, 2013
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#95
The REL .25 has only a 1K watt amp driving just one 15" driver. That's not much displacement in today's world of subwoofers ( and with subwoofage, it is all about displacement), but everyone has a different reference that they use. Like the Mustang owner who is given a ride in a McClaren, his contentment is destroyed by comparison. Just saying....:)
 

RogerD

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May 23, 2010
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#96
I use a Velodyne 18 and a custom dual 16 subwoofer and the largest difference in overall bass performance was not amplifier power or the room,it was a super low noise floor by using a grounding scheme. One thinks that grounding can not make a profound difference,but is the key to amazing bass and overall sound quality.
 

Ron Resnick

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#97
yes...that's what I remember as well; any luck finding a pair of these or have you determined what (other) sub will be in the system you are building up to Ron?
I do not think I will need subwoofers.
 

Ron Resnick

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#98

Lagonda

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#99
I owned a complete set of E2's 15 year ago in the US, but messed up and sold them when I moved back to Europe. Did not have the Room for them, should have put them in storage ! Knowing first hand how fast and versatile these subs are i took a chance when someone in Switzerland put the sub towers up for sale on a German website. I honestly thought it was probably a scam. And ecstatic when the 8 crates with 500 lb's of subwoofers arrived. The guy was a audiodealer that years ago represented Martin Logan, used them at one show and sold the stat-towers to a buyer that did not want the subs. Fast forward 10 years, the guy needs room in his warehouse and puts them up for sale ! They do not have a mark and where barely broken in. One custom spike was missing , but still available from Martin Logan, crazy!
Some times you get lucky !
 
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SCAudiophile

Well-Known Member
Sep 11, 2010
905
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455
Greer South Carolina (USA)
The REL .25 has only a 1K watt amp driving just one 15" driver. That's not much displacement in today's world of subwoofers ( and with subwoofage, it is all about displacement), but everyone has a different reference that they use. Like the Mustang owner who is given a ride in a McClaren, his contentment is destroyed by comparison. Just saying....:)
Marty: Good Morning!!! 1000W of power for one 15" driver is not enough? Seriously??? For 2 channel I would say it is more than enough; my last speakers had 500W amps (2) driving one each 12" bass and sub-bass driver and the results were paste you in-seat bass (you heard it here as they say!) and the bass and sub-bass had to be EQ'ed down to defeat a room mode. For home theater perhaps not (or if you want the room vibrating like one of those Honda Civics going down the highway with too many drivers and watts crammed in the trunk home-boy style, maybe you need more than a 1000 W for one driver...<LOL>!
 

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