"Wave Launch" and Subwoofer Placement?

[musicfirst1]

I would say that proper, tuned extension to below 20Hz does two things:

One is where you would expect; the bottom two octaves are fleshed out and if done well the transients and overall 'speed' of the presentation are improved. This is where the real art comes in. Dialing in the 40-to 20hz performance so there is NO negative impact is this critical region. (Think Michael Arnopol's amazing bass work on 'Ode to Billy Joe' on Patricia Barbers Cafe Blue, among others.) It's SO easy to mess this up.

Once one achieves the above, the next effect is easily heard on well recorded live recordings in medium to large venues. One is transported to the acoustic and the room disappears (examples of this are Belafonte at Carnegie Hall esp Matilda and many large symphonic works). I believe that the reason for this is the lower frequencies involved pressurize the listening room more effectively and transcend the walls of most listening rooms. (My room is open concept 4mw x 12ml x 3mh)
Its very easy to hear this effect in my system, as it is very easy to disconnect the high level Speakon connectors from the main amplifiers to the left and right sub towers, leaving just the main speakers.

For those not tired of my lunacy, here's my original post on dialing in the subs: Sadly, this must be completely redone from scratch for every different Room/Main Speakers/and Amplifiers.

https://www.whatsbestforum.com/threads/wilson-audio-thor’s-hammer-or-master-subsonic-subwoofers.27390/page-2#post-626051

 

[LL21]

Awesome...NOW the question is:

- did you ever test 1 or 2 subs...before you went to all 6? I am trying to figure out exactly what happens when you go 'all out' as you have relative to 1-2 subs (which many of us do).

Thank you!

 

[musicfirst1]

Well, one sub is harder to work with, I much prefer to start with two. Four and six just increase effect #2 above. I know of 8, 10, and even 12 packs out there.
Its very easy in my set up to disconnect 2 or 4 subs in any combination. I have even considered selling one pair, but I think all 6 are worthwhile and two, four and six sub configurations are easily audible and all offer positive contributions.

I know there are some, if not many, who are prejudiced against subs, but I would respectively say they are basing their opinions on either a faulty perception or experience with sub-optimal implementation.

 

[Lagonda]

Well, one sub is harder to work with, I much prefer to start with two. Four and six just increase effect #2 above. I know of 8, 10, and even 12 packs out there.
Its very easy in my set up to disconnect 2 or 4 subs in any combination. I have even considered selling one pair, but I think all 6 are worthwhile and 2 four and six sub configurations are easily audible and all offer positive contributions.

I know there are some, if not many, who are prejudiced against subs, but I would respectively say they are basing their opinions on either a faulty perception or experience with sub-optimal implementation.

I have 16 x 12 inch drivers in a 8 pack setup and had to do 4 packs with 8x12 inch drivers in a limited space dedicated home theater setting at one time. The 4 pack did not have the same impact and effortlessness as the 8 pack, kind of the same effect you often get when you go from stereo amps to mono blocks.

 

[musicfirst1]

FWIW, I do not use my system for HT. I think the tuning would be substantially different if i did.

 

[Lagonda]

FWIW, I do not use my system for HT. I think the tuning would be substantially different if i did.

Some crossovers will let you do both, Martin Logan Statement E2 crossovers has separate inputs for home theater sub channels, so you can do both. I personally don’t run HT
anymore, i have a dedicated 2 channel system these days.

 

[Robh3606]

FWIW, I do not use my system for HT. I think the tuning would be substantially different if i did.

Hello Music First100

I don't know I have an HT where my main consideration is 2 channel music and I have them set-up to sound the most balanced that way. I have no lack of impact or extension listening to movies. Just like 2 channel its the mix that determines just how hard the subs have to work.

Rob

 

[Ron Resnick]

Dear musicfirst100,

I just realized I have another question. Purely out of curiosity did you ever try the configuration with the REL towers were to the outside of each speaker?

 

[Duke LeJeune]

I have a question for you that hopefully a lot of us fans of bass (and you) will enjoy...and more than a few of us have contemplated. It relates to bass...specifically 'enormous bass capability' and specifically its ability to create spacial, atmosphere foundation and true envelope that even big tower speakers cannot do on their own. So here goes...

...lets say you have a room 40' long, 18' wide and 11' tall.
...lets say you already own tower speakers...XLFs, Grande Utopia EMs, Rockport Arrakis, etc

...lets say you already know from experience that a single, big JL Gotham, Velodyne DD18+, etc takes those speakers from a 2D + some 3D detailing...into a powerful 'suggestion' of a bigger envelope due to the subterranean spacial cues

...lets say you acknowledge that a SWARM of subs enables you to even out the bass performance, AND create a less demanding load on any one bass cone...so that distortion perhaps also goes down...further enhancing that 'suggestion of envelope/space of the jazz club, symphony hall, Bat Cave, etc...

QUESTION:

- what happens in your opinion if you enable your system 'virtually UNLIMITED' access to all-out bass (with SKILLED SET UP..."Stirling Trayle Standard" shall we say)? I am talking 1400-2000 square inches of cone surface area...the equivalent of dual 6 towers of dual-18" subs...each finetuned/setup or spread around the room...

First, apologies for the slow reply, I have been under the weather the past few days and unable to think clearly. Not that my thinking is necessarily all that clear under the best of circumstances...

Second, I DO NOT claim that any of this would be consistent or compatible with what Sterling Trayle does... and confess that I had to google who he is to even formulate this disclaimer.

So if we're going all-out for maximum sense of immersion/envelopment (without trading off natural ultradeep bass), here are some thoughts that come to mind:

We might not want to start out with main speakers that go all the way down. The reason is, if our main speakers already are plenty loud enough down as low as we want to go, then adding subwoofers becomes problematic in this sense: We risk ending up with TOO MUCH low-end output. The output from our subs will add to the output from the mains even if they are not perfectly in-phase; semi-random phase summing is not as strong as in-phase summing, but it still definitely happens.

If we have the option of decreasing the amount of bottom-octave-or-two output from our mains without compromising anything else, imo that may well be worth considering in this context.

Now let's get into HOW TO increase that sense of envelopment. David Griesinger, inventor of the Lexicon processor, made an interesting recommendation in a paper he wrote several years before Todd Welti and Earl Geddes came out with their respective multi-sub strategies. Griesinger suggested using two subs, placed along the left and right walls, approximately in line with the left and right ears of the listener(s). Then the phase controls would be adjusted such that the left and right subs were 90 degrees apart from one another (in what is called "phase quadrature"). Griesinger suggests that the phase difference at the two ears is detectable and is interpreted as sounding like we are in a much bigger acoustic space. So in effect this configuration "synthesizes" the impression of acoustic space, rather than extracting it from the recording.

Now you may be thinking, why not just use the stereo information on the recording instead of "synthesizing" anything? And imo that's a great idea IF the recording has true stereo bass. My understanding is that true stereo bass recordings are rather rare.

So what I'd suggest to maximize envelopment is this: Multiple subs largely arrayed along the left right hand walls, and send the left channel signal to the left-hand-ish subs, and the right channel signal to the right-hand-ish subs. Then have TWO optimized control settings: One for when you do have true stereo bass (in which case you would not set the two sides 90 degrees apart), and one for when you do not have true stereo bass (which would call for the phase quadrature settings). It is possible that the "optimum" other control settings might change as well between with- and without phase quadrature, hence my suggestion of two optimizations. The 90-degrees-apart phase quadrature setting would probably be the default for most recordings, and HOPEFULLY switching back and forth would be quick and painless.

Perhaps now my earlier recommendation for NOT having the main speakers produce full power bass all the way down makes more sense: We want the "envelopment optimized" signals from the subs to the left and right of the listening area to be loud enough to be dominant, which might not be feasible if the low bass from the mains is already plenty loud enough.

Finally, let's take an imaginary detour even further down the phase-quadrature-esque rabbit hole: We can increase the phase difference between the left and right channels to more than 90 degrees, which will increase the sense of immersion in a large acoustic space, but there is a tradeoff: This will tend to decrease the amount of very low bass energy in the room. On the other hand with highly capable subs, we can probably restore that very bottom end with equalization.

I hope there is something useful in this post. Feel free to ask for clarification, but just so you know I may be slow to reply.

 

[musicfirst1]

Dear musicfirst100,

I just realized I have another question. Purely out of curiosity did you ever try the configuration with the REL towers were to the outside of each speaker?

Yes over several months I tried both outside and inside the mains with both towers equidistant to the listening position, (imagine an arc WRT the listening position for the mains and the sub towers). I also tried the same inside and outside positions WRT the mains but further back like many tower sub setups many of us have seen (like for example the MBL Extremes and the big Genesis and Infinity IRS Vs etc..)
Along the way, I also tried the corners of listening room, as well as close to the front wall positioned half way edge to centre.

I preferred the equidistant position even though it was not the best spot from a bass reinforcement perspective. It did integrate better with the mains, and I was able to compensate for the bass response with the crossover and gain settings for the subs. Luckily the Rockport Cygnus were imaging champs at what would seem like an extreme outside position and I had no issue with image density or centre fill which I anticipated would be a problem with this setup.

Based on what I've learned previously, I suspect that the position I will finally arrive at for my new Bayz Audio Courantes will be either back slightly and outside the mains, or close to the front wall half way from the corners to the centreline.

 

[musicfirst1]

First, apologies for the slow reply, I have been under the weather the past few days and unable to think clearly. Not that my thinking is necessarily all that clear under the best of circumstances...

Second, I DO NOT claim that any of this would be consistent or compatible with what Sterling Trayle does... and confess that I had to google who he is to even formulate this disclaimer.

So if we're going all-out for maximum sense of immersion/envelopment (without trading off natural ultradeep bass), here are some thoughts that come to mind:

We might not want to start out with main speakers that go all the way down. The reason is, if our main speakers already are plenty loud enough down as low as we want to go, then adding subwoofers becomes problematic in this sense: We risk ending up with TOO MUCH low-end output. The output from our subs will add to the output from the mains even if they are not perfectly in-phase; semi-random phase summing is not as strong as in-phase summing, but it still definitely happens.

If we have the option of decreasing the amount of bottom-octave-or-two output from our mains without compromising anything else, imo that may well be worth considering in this context.

Now let's get into HOW TO increase that sense of envelopment. David Griesinger, inventor of the Lexicon processor, made an interesting recommendation several years before Todd Welti and Earl Geddes came out with their respective multi-sub strategies. Griesinger suggested using two subs, placed along the left and right walls, approximately in line with the left and right ears of the listener(s). Then the phase controls would be adjusted such that the left and right subs were 90 degrees apart from one another (in what is called "phase quadrature"). Griesinger suggests that the phase difference at the two ears is detectable and is interpreted as sounding like we are in a much bigger acoustic space. So in effect this configuration "synthesizes" the impression of acoustic space, rather than extracting it from the recording.

Now you may be thinking, why not just use the stereo information on the recording instead of "synthesizing" anything? And imo that's a great idea IF the recording has true stereo bass. My understanding is that true stereo bass recordings are rather rare.

So what I'd suggest to maximize envelopment is this: Multiple subs largely arrayed along the left right hand walls, and send the left channel signal to the left-hand-ish subs, and the right channel signal to the right-hand-ish subs. Then have TWO optimized control settings: One for when you do have true stereo bass (in which case you would not set the two sides 90 degrees apart), and one for when you do not have true stereo bass (which would include the phase quadrature settings). It is possible that the "optimum" other control settings might change as well between with- and without phase quadrature, hence my suggestion of two optimizations. The 90-degrees-apart phase quadrature setting would probably be the default, and HOPEFULLY switching back and forth would be quick and painless.

Perhaps now my earlier recommendation for NOT having the main speakers produce full power bass all the way down makes more sense: We want the "envelopment optimized" signals from the subs to the left and right of the listening area to be loud enough to be dominant, which might not be feasible if the low bass from the mains is already plenty loud enough.

Finally, let's take an imaginary detour even further down the phase-quadrature-esque rabbit hole: We can increase the phase difference between the left and right channels to more than 90 degrees, which will increase the sense of immersion in a large acoustic space, but there is a tradeoff: This will tend to decrease the amount of very low bass energy in the room. With highly capable subs, we can probably restore that very bottom end with equalization.

I hope there is something useful in this post.

I Totally agree with Duke on this, integrating my sub towers with the Rockport Cygnus that have usable output to 20 Hz is a BEAR!! Much easier, I would think to get mains that only go to 60-40Hz to integrate...

 

[Ron Resnick]

Yes over several months I tried both outside and inside the mains with both towers equidistant to the listening position, (imagine an arc WRT the listening position for the mains and the sub towers). I also tried the same inside and outside positions WRT the mains but further back like many tower sub setups many of us have seen (like for example the MBL Extremes and the big Genesis and Infinity IRS Vs etc..)
Along the way, I also tried the corners of listening room, as well as close to the front wall positioned half way edge to centre.

I preferred the equidistant position even though it was not the best spot from a bass reinforcement perspective. It did integrate better with the mains, and I was able to compensate for the bass response with the crossover and gain settings for the subs. Luckily the Rockport Cygnus were imaging champs at what would seem like an extreme outside position and I had no issue with image density or centre fill which I anticipated would be a problem with this setup.

Based on what I've learned previously, I suspect that the position I will finally arrive at for my new Bayz Audio Courantes will be either back slightly and outside the mains, or close to the front wall half way from the corners to the centreline.

Thank you.

By the way, the equi-distant arc method is recommended for the Gryphon Kodo and Pendragon and, I believe, for for the Evolution Acoustics MM7.

 

[musicfirst1]

Thank you.

By the way, the equi-distant arc method is recommended for the Gryphon Kodo and Pendragon and, I believe, for for the Evolution Acoustics MM7.

I think, Ron, the equidistant method is good for conventional speakers, I highly doubt It'll work for omnis... Imaging will be compromised almost certainly.

 

[LL21]

Thank you! This is fantastic. So now 3 basic questions which are bolded/underscored for ease:

1. What in your mind is the high level difference between the approach that Gryphon, Evolution Acoustics (MM7 Model), and musicfirst100 are talking about...which is super-large sub towers in 'equidistant arc' facing the listener...and your suggestion of subs along the left and right center walls facing "the listener's ears". (Or for that matter...the Genesis 1.2 or YG Acoustics Sonja XV or Wilson XVX/WAMM + Subsonics...where the sub towers are generally behind towards the outside of the main speakers?)

Is the arc method or 2 sub towers behind essentially creating a bigger/badder version of 2 speakers facing you...while the L/R center wall method is creating more 'surround sound'?

2. Regarding your warning of 'too much bass'...i totally get that. On the other hand...

2A. Is there a difference between playing 2 x 12" woofers loudly and 12 x 12" stacked woofers more softly (both placed in the same location) other than distortion? Somehow, I think the answer is a big yes...but if yes, I do not understand why. I have to imagine movement of air itself must have something to do with it, relative to 'realism'.

2B. Somehow, i look at the number of speakers out there in the 'reference' set and note that while some have greater 'scale' than others, most of them do NOT vary much in treble and mid cone square inches...it is in the bass. Therefore, I wonder whether there is a LONG way to go before one has created 'too much bass'...

- Most reference speakers seem to deliver around 60-120 square inches of treble and mid cone surface area...rarely much more or less than that.
- But the woofer square inches can vary massively from 180-200 square inches on smaller 'reference speakers which still have 1-2 x 1" tweeter and 2 x 6"-7" midranges...(Magico Q7, Rockport Lyra, etc)...to upwards of 400 and even 700-1000 square inches with sub towers (Evolution Acoustics, Wilson, YG, Gryphon, Genesis, Stenheim)...and then of course the REL dual-stack of 3 x 15" subs for each sub stack...

As a base starting point, do you find it appropriate for audiophiles to look for massive custom-designed/installed bass enhancement for reference speakers (ie, upwards of 500-1000 square inches of cone surface area...dual Thors, massive SWARM, REL dual-stack)?

First, apologies for the slow reply, I have been under the weather the past few days and unable to think clearly. Not that my thinking is necessarily all that clear under the best of circumstances...

Second, I DO NOT claim that any of this would be consistent or compatible with what Sterling Trayle does... and confess that I had to google who he is to even formulate this disclaimer.

So if we're going all-out for maximum sense of immersion/envelopment (without trading off natural ultradeep bass), here are some thoughts that come to mind:

We might not want to start out with main speakers that go all the way down. The reason is, if our main speakers already are plenty loud enough down as low as we want to go, then adding subwoofers becomes problematic in this sense: We risk ending up with TOO MUCH low-end output. The output from our subs will add to the output from the mains even if they are not perfectly in-phase; semi-random phase summing is not as strong as in-phase summing, but it still definitely happens.

If we have the option of decreasing the amount of bottom-octave-or-two output from our mains without compromising anything else, imo that may well be worth considering in this context.

Now let's get into HOW TO increase that sense of envelopment. David Griesinger, inventor of the Lexicon processor, made an interesting recommendation in a paper he wrote several years before Todd Welti and Earl Geddes came out with their respective multi-sub strategies. Griesinger suggested using two subs, placed along the left and right walls, approximately in line with the left and right ears of the listener(s). Then the phase controls would be adjusted such that the left and right subs were 90 degrees apart from one another (in what is called "phase quadrature"). Griesinger suggests that the phase difference at the two ears is detectable and is interpreted as sounding like we are in a much bigger acoustic space. So in effect this configuration "synthesizes" the impression of acoustic space, rather than extracting it from the recording.

Now you may be thinking, why not just use the stereo information on the recording instead of "synthesizing" anything? And imo that's a great idea IF the recording has true stereo bass. My understanding is that true stereo bass recordings are rather rare.

So what I'd suggest to maximize envelopment is this: Multiple subs largely arrayed along the left right hand walls, and send the left channel signal to the left-hand-ish subs, and the right channel signal to the right-hand-ish subs. Then have TWO optimized control settings: One for when you do have true stereo bass (in which case you would not set the two sides 90 degrees apart), and one for when you do not have true stereo bass (which would call for the phase quadrature settings). It is possible that the "optimum" other control settings might change as well between with- and without phase quadrature, hence my suggestion of two optimizations. The 90-degrees-apart phase quadrature setting would probably be the default for most recordings, and HOPEFULLY switching back and forth would be quick and painless.

Perhaps now my earlier recommendation for NOT having the main speakers produce full power bass all the way down makes more sense: We want the "envelopment optimized" signals from the subs to the left and right of the listening area to be loud enough to be dominant, which might not be feasible if the low bass from the mains is already plenty loud enough.

Finally, let's take an imaginary detour even further down the phase-quadrature-esque rabbit hole: We can increase the phase difference between the left and right channels to more than 90 degrees, which will increase the sense of immersion in a large acoustic space, but there is a tradeoff: This will tend to decrease the amount of very low bass energy in the room. On the other hand with highly capable subs, we can probably restore that very bottom end with equalization.

I hope there is something useful in this post. Feel free to ask for clarification, but just so you know I may be slow to reply.

 

[stehno]

There seems to be two schools of thought on this.
One: The optimum placement of subs has more to do with the nulls and nodes in the listening room and;
Two: The subs should be first and foremost placed with wave launch considerations. I assume wave launch optimization being achieved by testing the impulse response of a low frequency series of pulses.

Assuming the main speakers are good to 30 Hz. Does the wave launch criteria of the subs matter?
What is the relationship between sub placement, wave launch, and phase? My subs only do 0 and 180 degrees.

There was a good article (from JLAudio?) that covered multiple sub placements in excellent detail, but I can't find it, and don't recall if this topic was covered..

Kerry, if you're still having fun dialin' in the bass, here's a nice little gem that could assist.

I consider this recording a real sleeper because many of us have heard this a hundred times or more and probably never gave it much thought other than being cute.

When bass is not dialed in percussions are rather nondescript with unbalanced presentation, etc. But when the bass is dialed in, percussions become unmistakeably very pronounced, visceral, well-defined, deeper, tighter, etc, balanced presentation, and easily becomes the foundation of the entire cut.

Depending on headphones used, you may or may not hear it in this video, but the cell phone on the tri-pod impacted with every beat should give some indication what's going on in the room.

This could be an excellent piece for both subs and mains because when dialed in, since the before / after is quite a noticeable difference.

 

[Mark Seaton]

Hi Lloyd,

This was an interesting and entertaining discussion of different low frequency solutions that I missed the start of, but recently noticed this set of questions was left unaddressed.

I know this was directed at Duke's line of answers, but I'll add a few thoughts of my own. A few more recent setup/calibrations I've worked on have allowed some unique configurations and range of adjustments, giving a little insight on ways to deliver the lowest frequencies in our listening rooms. I purposely make reference to multiple methods as the is no single ideal answer for all systems and rooms.

Question 1 comparing equidistant main speakers and sub towers vs more flexible placement options has many dependent variations where the specific qualities of the listening space and placement of speakers and subs within the room are going to play a role in how the different options work out. The side wall with phase shift suggestion is an interesting concept, but quickly becomes intertwined with the even delivery of the low frequencies to the listener. This recommendation from David Griesinger was in response to a subjective perception of "bass in the head," which became of interest well before we had such ready availability of measurement equipment. I've never seen this problem demonstrated in a system without strong modal resonances due to room and sub/speaker placement, and still question if it's chasing a red herring.

There are are most certainly interactions between multiple low frequency sources, the room, and the resulting magnitude and time behavior at the listener which affect the perception of low frequency origin and cohesion with the sound of the speakers. We do have to remember that many 2 channel system ideals, goals of purity, or component selection automatically limit what flexibility we have in adjustment.

The location of the subwoofers have impacts beyond just the direct time-of-flight, as at the lowest frequencies, it's a fuzzy separation of direct energy vs the overall interaction with the room. Significant changes in the frequency response do affect the time domain, and our hearing is quite sensitive to changes in the decay of the bass/subwoofer spectrum, so there's no case of physical alignment where it makes sense to ignore the magnitude (frequency) response. There are some coincidences we often see with certain approaches that happen to also work out from a modal/response perspective. Looking at what works from such configurations and what might be missing from a measurement standpoint can give pointers in where to experiment and test next.

Question 2: There is difference to a larger area, more distributed bass source vs a more condensed point. In terms of a reasonable size box/cube vs a tower, so long as the tower isn't just a single, elevated point, it usually offers some advantage with respect to room interaction. So far as actual production of bass energy, it's very easy to underestimate the dynamic distortions in a real loudspeaker, especially as each voice coil starts getting more than 10-100W in more than the shortest of bursts. Remember that in terms of surface area, 12 vs 2 woofers is equivalent to using 6x larger diameter voice coils in the 2 woofers, and the required excursion from the cone reduces by 6x for the same SPL. That means the level that would require more than 6mm of one-way travel just shifted more than 15dB higher.

Put another way, the sound output which required a peak of +/-6mm of cone movement from the pair, well within the intended limits of most any modern, subwoofer driver, now only requires +/-1mm of motion, and each voice coil sees *1/36th* the amount of power when we move to 12 woofers. That is quite a significant difference in operating conditions for both the woofers and the amplifier driving them. It's impressive if a driver designer is able to double the power handling or linearity of a given woofer design without significant compromise elsewhere. This is a multiplier of capability with the primary compromises being total box size and cost.

2B: For wide dispersion designs, midrange and HF diameters will be necessarily limited due to maximum width and spacing from the adjacent bandwidth drivers. If you look at displacement capabilities in the 50-150Hz and 100-500Hz range, you will see much more variation. Of course I use the metric of displacement not surface area, as there are many cases where woofer choice can make for 2-4x the displacement capability from the same size cone. Generally with larger Sd at lower frequencies, the higher possible system sensitivity, up to the limits set by the mid and tweeter. This choice of woofer cone area and overall sensitivity also dramatically affect the required enclosure size.

This makes a strong case for separate woofer columns, as keeping the upper frequencies on smaller dimension boxes (even if tall) makes resonance free construction easier, while woofer columns then can be larger and not as concerned about resonances above a few hundred Hz. The dilemma is of course that a monolithic speaker eliminates another variable in setup, narrowing the possible options to try in a room, and leaves less rope for the owner.

Thank you! This is fantastic. So now 3 basic questions which are bolded/underscored for ease:

1. What in your mind is the high level difference between the approach that Gryphon, Evolution Acoustics (MM7 Model), and musicfirst100 are talking about...which is super-large sub towers in 'equidistant arc' facing the listener...and your suggestion of subs along the left and right center walls facing "the listener's ears". (Or for that matter...the Genesis 1.2 or YG Acoustics Sonja XV or Wilson XVX/WAMM + Subsonics...where the sub towers are generally behind towards the outside of the main speakers?)

Is the arc method or 2 sub towers behind essentially creating a bigger/badder version of 2 speakers facing you...while the L/R center wall method is creating more 'surround sound'?

2. Regarding your warning of 'too much bass'...i totally get that. On the other hand...

2A. Is there a difference between playing 2 x 12" woofers loudly and 12 x 12" stacked woofers more softly (both placed in the same location) other than distortion? Somehow, I think the answer is a big yes...but if yes, I do not understand why. I have to imagine movement of air itself must have something to do with it, relative to 'realism'.

2B. Somehow, i look at the number of speakers out there in the 'reference' set and note that while some have greater 'scale' than others, most of them do NOT vary much in treble and mid cone square inches...it is in the bass. Therefore, I wonder whether there is a LONG way to go before one has created 'too much bass'...

- Most reference speakers seem to deliver around 60-120 square inches of treble and mid cone surface area...rarely much more or less than that.
- But the woofer square inches can vary massively from 180-200 square inches on smaller 'reference speakers which still have 1-2 x 1" tweeter and 2 x 6"-7" midranges...(Magico Q7, Rockport Lyra, etc)...to upwards of 400 and even 700-1000 square inches with sub towers (Evolution Acoustics, Wilson, YG, Gryphon, Genesis, Stenheim)...and then of course the REL dual-stack of 3 x 15" subs for each sub stack...

As a base starting point, do you find it appropriate for audiophiles to look for massive custom-designed/installed bass enhancement for reference speakers (ie, upwards of 500-1000 square inches of cone surface area...dual Thors, massive SWARM, REL dual-stack)?

 

[LL21]

Wow...I read that 3 times thru! Thank you! That is very, very cool. So my immediate takeaways are that:

1. Contrary to amateur 'conventional wisdom' which says a bunch of smaller woofers should be 'tighter more accurate' than a single or pair of larger cones...it sounds like when one considers that the smaller woofer has a higher excursion requirement (ie, as you say, not just surface area but cubic air movement/displacement)...it could be that there is every reason to think that 2 x 18" cones sub could end up having a much easier (ie, less distortion) time of producing bass than an 8 x 9" cones tower sub (despite their having the exact same surface area).

2. The placement of the subs in a 4-tower speaker (set back in the corners a la Genesis or Wilson vs aligned in curve a la Alsyvox or certainly Genesis) is simply a matter of different approaches to a complex web of interactions between speaker columns and the room boundaries. One method is not more precise than the other.

3. Looking for separate woofer enclosures (up to very very big ones) has benefits not just in creating that 'bedrock foundation' to music but because it enables the main speakers to avoid the inevitable issues of a really fat/wide speaker that is also vibrating like crazy.

So now let me ask you a question that just came up when i was speaking with my local dealer about options....

 

[LL21]

...we were discussing the pros/cons of going with a 3rd party sub (Seaton, Funk for custom work or JL, Velodyne, Paradigm for 'off the shelf high end work')...vs going with the sub that was designed by the same speaker manufacturer (Wilson)

...and the question arose of whether (even at frequencies below 38-40hz where most big Wilson owners cut off their subs)...the sub 'sound' can either match or be somewhat disparate in character from the main speaker

I have heard from some Wilson owners who have owned big SOTA 3rd party subs that going to the Thor was not necessarily a quantitative difference in scale or power of bass...but in CHARACTER of bass where they felt the main Wilson speaker and the Thor seemed much more 'of one kind' than they had ever been able to manage before with their 3rd party subs.

Can that really be true given that we are talking:
- sub 40hz
- usually lots of adjustability in phase, volume, parametric equalizers, crossovers
- and a new one for me...low levels of system latency??

 

[Mark Seaton]

...we were discussing the pros/cons of going with a 3rd party sub (Seaton, Funk for custom work or JL, Velodyne, Paradigm for 'off the shelf high end work')...vs going with the sub that was designed by the same speaker manufacturer (Wilson)

...and the question arose of whether (even at frequencies below 38-40hz where most big Wilson owners cut off their subs)...the sub 'sound' can either match or be somewhat disparate in character from the main speaker

I have heard from some Wilson owners who have owned big SOTA 3rd party subs that going to the Thor was not necessarily a quantitative difference in scale or power of bass...but in CHARACTER of bass where they felt the main Wilson speaker and the Thor seemed much more 'of one kind' than they had ever been able to manage before with their 3rd party subs.

Can that really be true given that we are talking:
- sub 40hz
- usually lots of adjustability in phase, volume, parametric equalizers, crossovers
- and a new one for me...low levels of system latency??

As a quick response I would suggest that a great deal of those character differences come down to design philosophies where just the shape of the low frequency roll off makes for some dramatically different personalities when you initially drop a sub in the room and hear the interaction of that out of the box frequency response interacting with your room. For intended crossover frequencies below 40Hz, latency itself isn't going to be hugely audible, but differences in low pass filtering will sound different (what is best could vary greatly with speakers and system/room). The in-room, useful low frequency extension will vary quite a bit between designs, some having significantly different port tuning frequencies which set some hard practical limits, and within sealed subwoofers the optimizing electronics and internal protections can limit useful extension. You can see this limit change in the various JL Audio models where they cut off the very lowest frequencies in all of the models, with the Gotham allowing the lowest extension, even though you might expect 4 of the F113s to have more capability. Velodyne did similar with the 12" vs 18" models. From a maximum output perspective you can make a justification, while my own designs allow even compact (multi-driver) 8" and 12" designs I have in the works to achieve the same deep extension of the 18" and now 21" I offer.

Flexible EQ systems will allow differing subwoofers to have more similar performance if both have sufficient low frequency extension and headroom, but it takes some care of someone rather experienced to match exceptionally close, as overall shape/tilt/balance vs the rest of the frequency range is something we are quite sensitive to subjectively. There are also significant differences in distortion behavior vs level and frequency with different subwoofers from different companies. Even working below 40Hz, distortion and other dynamic differences can be readily audible.

I would be less inclined to say the subs need to match the speaker voicing, but rather the preference and sensitivities of the listener, and depending on what is available for comparison, that might happen to be the same manufacturer as the speaker.

 

[LL21]

Thank you...very interesting and helpful for a non-techie to be able to follow and get a slightly clearer picture of what I may be looking for in my search for bass that has to live within certain physical constrains within the room...but otherwise is targeted to be as all out assault as possible. I may PM you or email you directly.