Bass Stacks

SCAudiophile

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Sep 11, 2010
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dctom

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infintely bafled

It is too bad that you didn't go ahead with your Infinite Baffle project. These are not as complicated as it looks, especially that you had already build space for them. As for performance, they would for much less money and I mean , much , much less run circle around anything commercial you could fathom. An investment of $10K in an IB would outperform those 8 Krell MRS. They wouldn't carry the reputations or the audiophile prestige that could come with the MRS but in term of performance and return on investment and pure sonics ??
This being a hobby, please do enjoy what you have or want to have but in term of sheer performance and sonic quality few subwoofers alignment surpass a correctly made IB. On top of that you can still add smaller subs throughout the rooms to smooth the response ... An IB is IMHO a win-win solution.

IB subs are not very high on the audiophile star chart but they give fantastic results. The 500w x 2 sub amps I use with my 18 inch drivers are the same as the ones Kevin Scott uses (to drive L& R subs) with the spiritland 100k GBP+ speakers and only cost around £600 the pair .

Coupled with a 15in freestanding sub I get a very linear response, down to 10Hz.
 
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infinitely baffled

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I believe this thread is now deserving of a "pictures or it didn't happen" prompting. :)

I struggle with pictures...ok very deep breath here we go
 

infinitely baffled

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4 x DD18 + in stereo bass stacks

Here goes....
 

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infinitely baffled

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Does this work?
 

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infinitely baffled

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a quick update

Nick was here yesterday, a successful visit installing the second pair of 18's.
As it was the hottest day of the year so far for this part of the uk we got the eq and setup done, had a quick listen and then headed out to enjoy the weather. There's a natural amphitheatre just the other side of the valley by a secluded bend in the river, so went with my gf and took the dogs for a swim. On return I did my chores and settled down with a glass of bubbly to see what was what.

Ok first impression was as Nick was here doing the test signal sweeps and it was just how powerful the system was sounding, the whole house felt like it was shaking. Then we played some tunes and it sounded as though we had upgraded my main speakers to grande utopias; my system appeared to have doubled in size and no longer sounded as though there were separate subwoofers. And the thing that really stood out was how much better the main speakers were sounding...I was hearing more detail in the mids and tops, a big increase in the size of the soundstage and just a breathy realism all across the frequency range.
At this point I need to share that recently I've upgraded the pair of balanced i/c that runs for 9m from one side of the room to the other, linking pre to power amps. After reading from a member here that Mogami microphone cables were a useful stop gap I'd been using them to cover the distance but intended to upgrade them. Now I have replaced them with JPS Kaptivator Sc3 and it's like the dam has burst, and all of the life in the upper registers has returned, especially texture and imagery. So now that Nick had rerun the eq I was getting the full benefit and it was sounding really, really good

But what of the bass....Well the two new 18's are box fresh and past experience has shown that they will break in over the coming month. But weight, impact and power are off the chart, with articulation not quite where the mixed stacks were, but hopefully that will come as they loosen up.
It has made me wonder about getting the 15's back as well....I've already alerted Nick to my thinking, we'll see how the new 18's settle but I haven't completely discarded my theory that the slightly different voicing of the 15's brings something to the party

Ok more detailed observations to come over the next few weeks....watch this space ?
gav
 

infinitely baffled

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Jul 2, 2015
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So far today I have experienced 'get ur freak on' by Missy Elliot reminiscent of how a massive funktion 1 sound system at Notting Hill Carnival energised an entire city block with its incredible bass slam, reverberating off the terraced mansion blocks set back from either side of the street.
Plus one of my current fave albums 'brand new machine' by Chase and Status sounding absolutely stupendous, with percussive bass seeming to flex my walls
 

Mark Seaton

WBF Technical Expert (Speaker & Acoustics)
May 21, 2010
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Chicago, IL
www.seatonsound.net
Nick was here yesterday, a successful visit installing the second pair of 18's.
As it was the hottest day of the year so far for this part of the uk we got the eq and setup done, had a quick listen and then headed out to enjoy the weather. There's a natural amphitheatre just the other side of the valley by a secluded bend in the river, so went with my gf and took the dogs for a swim. On return I did my chores and settled down with a glass of bubbly to see what was what.

Ok first impression was as Nick was here doing the test signal sweeps and it was just how powerful the system was sounding, the whole house felt like it was shaking. Then we played some tunes and it sounded as though we had upgraded my main speakers to grande utopias; my system appeared to have doubled in size and no longer sounded as though there were separate subwoofers. And the thing that really stood out was how much better the main speakers were sounding...I was hearing more detail in the mids and tops, a big increase in the size of the soundstage and just a breathy realism all across the frequency range.
At this point I need to share that recently I've upgraded the pair of balanced i/c that runs for 9m from one side of the room to the other, linking pre to power amps. After reading from a member here that Mogami microphone cables were a useful stop gap I'd been using them to cover the distance but intended to upgrade them. Now I have replaced them with JPS Kaptivator Sc3 and it's like the dam has burst, and all of the life in the upper registers has returned, especially texture and imagery. So now that Nick had rerun the eq I was getting the full benefit and it was sounding really, really good

But what of the bass....Well the two new 18's are box fresh and past experience has shown that they will break in over the coming month. But weight, impact and power are off the chart, with articulation not quite where the mixed stacks were, but hopefully that will come as they loosen up.
It has made me wonder about getting the 15's back as well....I've already alerted Nick to my thinking, we'll see how the new 18's settle but I haven't completely discarded my theory that the slightly different voicing of the 15's brings something to the party

Ok more detailed observations to come over the next few weeks....watch this space ?
gav

The pictures certainly help giving a better idea of what you have set up. Thank you for sharing.

On the matter of break in, if Nick comes out again, have him queue up a ~16Hz sine wave and throttle the 2 new subs at or near their max for about 3 seconds at a time, 30-60 seconds between, 3-4 times, take a break, and then repeat 2 more cycles. That should safely get you 80% there.

The articulation comes entirely from the balance of the upper and deeper bass frequencies, combined with the upper extension of the subs. I suspect to satisfy your tastes, Nick might have the range below 25-45 a little strong vs the 50-100Hz range. Finding the best blend for your room, speakers, and taste requires some fine tuning, and is fairly touchy with 0.5-3dB changes over the full bandwidth or exact tilt of the response being very noticeable once things are in the ballpark as it sounds like you are now. You probably want just a little more of the entire sub range and less ramp up to the bottom end to get what you are after. A little tinkering with the phasing between the two will also affect this aspect.

Of course the Trinnov would give you a direct means of adjusting these qualities through the curve editing and crossover adjustments.

Q: What are the pro-looking behemoths I see hiding in the front corners?
 

infinitely baffled

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Jul 2, 2015
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Hello again Mark
Thank you very much for your advice. With an average of 4-6 hours per nights use the running in process has previously been quite rapid....also I quite enjoy hearing things tightening up and gaining articulation, so no rush really ?

As for the vending machine - sized horns in the corner, that sir is a pair of EAW MC 4973f, dolby THX spec, full range cinema speakers. They are destined to go outside, along with four matching EAW BH883 aka big Bertha aka Levan subwoofers that we will build next year. This year's task is to complete the digging out of the ampitheater in my garden, building on the work of previous years. We've moved about two and a half thousand tons of earth and rock to date.
What we are learning inside with the bass stacks will likely be put to good use outside, Trinnov could be the way to go there also
 

infinitely baffled

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Jul 2, 2015
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We might be reaching the limits of my home's power supply....when other, high current devices are on the subs are having some difficulties.
Nick is returning on the 13th with a Torus power supply to feed the subwoofers, hopefully this can resolve the issue.
He's also bringing the Trinnov st2 over for a play.
I'll post an update
 

infinitely baffled

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Jul 2, 2015
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Thanks for jumping in Nick,

Indeed, it wasn't clear what sort of levels the OP was looking for. Stacks most certainly work well, and I'd strongly recommend picking a sub that fits the performance need in bandwidth, and scaling up rather than mixing different versions. We recently did this setup at AXPONA 2017 in 1/3rd of the Chicago Westin O'Hare's grand ballroom where the room was 47 x 81 x 22. For LFE effects we could use the full capability, but for music this just gave us effortless headroom:



For scale:

Wow !

I've only just been able to view your pictures, Mark
Which model sub have you stacked there?

OK now please file this under 'dumb things punters have asked'...
But could there be any merit in turning one pair in each stack the opposite direction, to achieve dipole - like omni directional bass?
 

Mark Seaton

WBF Technical Expert (Speaker & Acoustics)
May 21, 2010
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Chicago, IL
www.seatonsound.net
Wow !

I've only just been able to view your pictures, Mark
Which model sub have you stacked there?

Those would be our F18+ and F18-Slave modular subwoofers (more info here). One F18+ contains a 4000W, US made amplifier which has the capability of driving up to 3 additional slave units (4 18s per 4000W amplifier). They don't have to be stacked, but obviously work well when you want to minimize footprint and don't need additional locations. We used 2 of the same stacks in this theater I detailed here on WBF. As you can see in my avatar, three stack up nicely as well. :cool: I have had other customers put two stacked pairs in all 4 corners with a one powered unit up front and one powered unit in the rear. The latter is probably the most flexible solution for home theater use and multiple rows in a more typical, enclosed, rectangular room. Forum member audioguy has 4 in the front of his theater and is planning swapping an earlier design of mine for a matching set at the rear of his theater.

For 230V/overseas operation the F18i+ version is required which does afford even more amplifier headroom and power line regulation in the 6,000W version of the same amplifier design (it delivers less power at 120V and costs more which is why we don't recommend it stateside).

While I understand where the scale of the stack and 18" woofers and common demonstration in home theater use make some question if they are truly hi-fi quality, the F18 is exceptionally low distortion, provides 7-12Hz extension in most rooms, and the headroom allows the low distortion motor to always remain in control of the glass-fiber honeycomb cones. Effortless and bottomless is the best description of what they sound like when you assemble enough for ample headroom and have them blended well with capable main speakers.

OK now please file this under 'dumb things punters have asked'...
But could there be any merit in turning one pair in each stack the opposite direction, to achieve dipole - like omni directional bass?

There would be almost zero acoustic benefit. For these wavelengths moving 2 of the 4 to the back simply moves those woofers ~18" further, which is about the same as simply moving the stack 9" back (summed result is the midpoint). At the frequencies these will be used, the 18" woofer s and 23.5" wide cabinet don't create any forward directivity, so they really are already omnidirectional.

If we locked them all together with 2 firing opposite directions it would create a force cancelling assembly where the drivers would physically push against each other, similar to my dual opposed SubMersive subwoofer, but with 3-4 stacked units, simply putting spikes on the bottom unit is enough to keep them quite still. An interesting benefit of the column of woofers is the way in which they all push on the column evenly top to bottom, such that the woofer moving fore-aft doesn't create a desire for the tower to rock, but rather it has a subtle effect for the whole column to quiver forward and back when we really push the excursion of the woofers. Even this is really only noticeable when we have the 460 lbs on the 4 rubber feet. If rigid spikes are inserted in place of the M6 feet, there is almost no perceivable movement.
 

Ron Resnick

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Dear Mark,

Your products in those photos look amazing!

Did you ever decide to pursue the "audiophile versions" of your subwoofers?
 

Mark Seaton

WBF Technical Expert (Speaker & Acoustics)
May 21, 2010
381
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Chicago, IL
www.seatonsound.net
Dear Mark,

Your products in those photos look amazing!

Did you ever decide to pursue the "audiophile versions" of your subwoofers?

Yes, this is something I will be pursuing as resources, especially available time, allow. I've been amidst the addition of 6 new speaker/subwoofer models or versions with a few more to come, updates of my Catalyst speaker models, and working on updates, improvements, and supplier changes to a few other models. I do have a few prototypes at my home and in a local friend's listening room and am quite impressed with how the first concepts are sounding and performing. Obviously there's no reason to offer a "me too" product, but I think I have found some great qualities and capabilities I can bake into the designs which will better align with the uses and priorities of the 2ch/audiophile market while still keeping very much in line with what I've delivered in products over the past 12 years. When I can justify the experimentation with the more expensive cabinet materials and have a production sample, I'll definitely be looking for a few to give them a test drive.
 

Ron Resnick

Site Co-Owner, Administrator
Jan 24, 2015
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That sounds very exciting!

You have a lot of fans here, and I know many people will be very interested in your designs with more exotic cabinet materials (heroically sturdy and heavy phenolic resin?) or other audiophile tweaks (Class AB amplifier instead of Class D?).
 

Steve Williams

Site Founder, Site Owner, Administrator
Yes, this is something I will be pursuing as resources, especially available time, allow. I've been amidst the addition of 6 new speaker/subwoofer models or versions with a few more to come, updates of my Catalyst speaker models, and working on updates, improvements, and supplier changes to a few other models. I do have a few prototypes at my home and in a local friend's listening room and am quite impressed with how the first concepts are sounding and performing. Obviously there's no reason to offer a "me too" product, but I think I have found some great qualities and capabilities I can bake into the designs which will better align with the uses and priorities of the 2ch/audiophile market while still keeping very much in line with what I've delivered in products over the past 12 years. When I can justify the experimentation with the more expensive cabinet materials and have a production sample, I'll definitely be looking for a few to give them a test drive.

Hi Mark

It is always so good to read your posts here and more than anything that your business is thriving. Keep up the good work and hope to see you soon and best of luck in your business ventures
 

audioguy

WBF Founding Member
Apr 20, 2010
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Near Atlanta, GA but not too near!
I am a big Seaton fan and in a few weeks will end up with 8 of his F18's. (Currently have 4 F18's and 2 of his SubMersives - but want all of the same sub).

In trying to assist me in sub placement, Mark pointed me to REW which is free measuring software that will run on a mac or a PC. I already have measuring software but in the software there is a subwoofer placement simulation mode, which, as it turns out, is VERY accurate - not perfect but more than accurate enough. It allows you to place up to 4 subs (6 if you make the mains subs) anywhere in the room, including stacking them.

Highly recommended as a staring point and it beats the heck out of moving subs around and measuring them - which is still, in my mind, eventually necessary to validate your findings.

Again, highly recommended.
 

Mark Seaton

WBF Technical Expert (Speaker & Acoustics)
May 21, 2010
381
141
390
47
Chicago, IL
www.seatonsound.net
That sounds very exciting!

You have a lot of fans here, and I know many people will be very interested in your designs with more exotic cabinet materials (heroically sturdy and heavy phenolic resin?) or other audiophile tweaks (Class AB amplifier instead of Class D?).

We already use and I work with some builders of exceptionally low distortion woofers. These do not always provide the highest level of output for their size, but are highly capable with typical music demands, and multiple units can make for highly impressive movie playback for those pulling double duty or for the audiophiles wanting something even more refined in their home theater system. I've regularly demonstrated over the past 12 years how we can reliably deliver 6-12Hz in-room extension with the sealed subwoofers I've offered, and even done a few ported and bandpass subs tuned into the 9-12Hz range. Delivering such extension while maintaining the upper bass articulation can be a trick, and is not automatic, but very important.

I have a few concepts I'll pursue, but will start with a couple sealed solutions with front end DSP and the latest ICEpower amplifiers which are quiet and very well behaved for subwoofer use. I see a definite need for some competent dipole/open baffle woofers, and some examples of each we can do with external analog electronics if desired.

One of the materials I'll be experimenting with will be quartz, as the manufactured nature makes is consistent and super stiff while not needing exotic finishing beyond polishing. We'll see what gets finalized first.

Thank you for you compliments and enthusiasm,
 

LL21

Well-Known Member
Dec 26, 2010
14,376
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We already use and I work with some builders of exceptionally low distortion woofers. These do not always provide the highest level of output for their size, but are highly capable with typical music demands, and multiple units can make for highly impressive movie playback for those pulling double duty or for the audiophiles wanting something even more refined in their home theater system. I've regularly demonstrated over the past 12 years how we can reliably deliver 6-12Hz in-room extension with the sealed subwoofers I've offered, and even done a few ported and bandpass subs tuned into the 9-12Hz range. Delivering such extension while maintaining the upper bass articulation can be a trick, and is not automatic, but very important.

I have a few concepts I'll pursue, but will start with a couple sealed solutions with front end DSP and the latest ICEpower amplifiers which are quiet and very well behaved for subwoofer use. I see a definite need for some competent dipole/open baffle woofers, and some examples of each we can do with external analog electronics if desired.

One of the materials I'll be experimenting with will be quartz, as the manufactured nature makes is consistent and super stiff while not needing exotic finishing beyond polishing. We'll see what gets finalized first.

Thank you for you compliments and enthusiasm,

Very interesting indeed! Do you recall the old Celestion SL6000 dipole subs which went underneath the SL600si bookshelf speakers to make them more full range? https://www.stereophile.com/floorloudspeakers/892/index.html

celestion SL6000.jpg

Any thoughts on this design?
 

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