Bass Stacks

infinitely baffled

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Hi ib',

You outline an entertaining journey there. The solid wall vs many windows opposite will almost always result in the best bass being produced near the solid wall. As you have found you can find workable locations to deliver the energy to the seats, or use EQ to bulldoze through the trough. If your dealer gets comfortable enough with the Trinnov unit, an Amethyst might be a great addition, assuming he can make the correct settings to not disrupt or enhance the sound you enjoy from your Stella Utopias. Without the ability to align the subs with the speaker's bass energy, the side locations will likely be tricky to blend. The Trinnov would make that much easier, and with so many windows I suspect the added control in setup will be welcome.

So far as the stacks of subs, you will almost always get better results and have a better shot at getting best usage of all units if they are the same. A stack of 3 DD+ 15 or 18" subs per side should work very well with the EQ to smooth the result at the listening area. The only down side to EQ'ing up the depressed frequencies at the listening position is that you can then end up with that much more energy in some other areas where the sound does not cancel, such as at the rear wall. Sometimes this gives an impression of more overall energy in the room vs. when the energy is higher or more uniform at the listening position. Ultimately in the setup you can experiment with slightly under-correcting the dips at the listening position by a small bit. A 1-3dB reduction over a good fraction of an octave can be quite audible in perceived power and overall balance.

Of course if you want to entertain something a bit more powerful, you know where to find me. :cool:

Hello Mark

Thank you for your insights ?

I think we may have had a brief conversation a year or so ago, i believe what stopped me from offering you the commission was that unfortunately I live on the other side of the pond.....so I thought maybe I should dip my toe in the water locally first and see how I get on, plus hopefully gain some knowledge about exactly what my room is doing so I can have a more educated conversation when it comes to the next step. But I am absolutely not considering this my final destination, more of the getting the ball rolling scenario.
If you have any ideas you would like to run past me I'm all ears....speaking of which as a result of your advice I'm trading the 15's up to 18's this weekend ?
 

infinitely baffled

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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.





Hello Franz, and thank you for your reply

I still haven't ruled out the IB sub, but unfortunately I took a step backwards when I swapped my room around as I had already cut a hole for a large manifold in the ceiling in what is now the wrong end of the room...so we patched it up.
However when I was researching the project I learned that the first step is to use a conventional subwoofer to figure out the best location for the IB subs....and later on I've learned that even IB subs can benefit from the assistance of a conventional sub or two to even out the room repsonse, so one might be able to still say that I'm on the path.
The only problem is, the more I've learned about the complexity of subwoofer / main speaker / room interactions, the less confidence I have that my kindergarten - level approach of measuring distance from listening position to main speakers and then locating the IB sub the same distance from the LP is lacking the necessary sophistication
So in essence I need a local IB guru, and they're a bit thin on the ground in these parts ?
 
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infinitely baffled

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Thank you for reporting your interesting journey with subwoofers. When you had the Paradigm Sub2 did you use one or two of them? (I ask because it may not have been fair to compare one Sub2 against two DD18+s?).

PS: Your report on the Sub2 is interesting because I thought the whole concept of the Sub2 was to use a large number of small and, therefore presumably fast, drivers.

Hello again Ron

I've been trying to remember the reasons we went Velodyne over Paradigm and I recalled a major one over the weekend.
The low pass filter of the Sub2 was/is set much higher than I wanted, given that the Stellas do have prodigious bass output.
This gave the impression of the Stellas' toes being trodden on by the Sub2 with an unwanted thickening to vocals and leading edges of bass. With the Velodynes we're able to roll them in lower down and let the Stellas do what they do best, which to my ears is anything above 25hz in room
 
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LL21

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will be most curious to learn how the system sounds when you swap the DD15+/DD18+ stacks with the new DD18+ dual stacks...
 

infinitely baffled

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Watch this space ?
 

LL21

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for sure!
 

infinitely baffled

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Plus my refreshed 2060 is due back any day....the child in me has much to be excited about this month
 

Mark Seaton

WBF Technical Expert (Speaker & Acoustics)
May 21, 2010
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I am working with the OP and this is a great project to be involved in. The one thing missing from the description is the volume we are looking to achieve. I have several cinemas where we are pushing the SPL as you would expect but only a few hi-fi systems at this performance level where the upper limit of volume is required. The addition of the DD15+ to each stack made a huge difference to the detail we can achieve in the lower reaches at peak performance and are very much an addition to the whole system rather than a stand out part. I will add more on the comparisons and additions later on.
Nick

Hi Nick, Did you happen to capture what sort of response you were able to get at the listening position with and without using Velodyne's internal EQ? Am I correct to guess the subs have a good rise to the measured response vs the upper frequencies in such a space and for the listening levels/preferences? Trinnov was mentioned, am I correct to assume you were considering an Amethyst for the system?
 

Mark Seaton

WBF Technical Expert (Speaker & Acoustics)
May 21, 2010
381
141
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Chicago, IL
www.seatonsound.net
Hello Mark

Thank you for your insights ?

I think we may have had a brief conversation a year or so ago, i believe what stopped me from offering you the commission was that unfortunately I live on the other side of the pond.....so I thought maybe I should dip my toe in the water locally first and see how I get on, plus hopefully gain some knowledge about exactly what my room is doing so I can have a more educated conversation when it comes to the next step. But I am absolutely not considering this my final destination, more of the getting the ball rolling scenario.
If you have any ideas you would like to run past me I'm all ears....speaking of which as a result of your advice I'm trading the 15's up to 18's this weekend ?

That's a well understood path to explore first. There may even be some upcoming options where we could work with your local dealer as well. The main point of interest is how high in frequency do you need your subs to augment your speakers due to room acoustics? Looking back I see the subs ended up next to your Stella's. Without seeing measurements I can't know for sure, but typically you will get better results if you can move the subs a bit forward or a bit behind the speakers in front-back depth. This will change the acoustic interaction with the length of the room, which is what causes most of the peaks and dips you are fighting. You don't have to come all the way to 1/2 depth, but moving forward or back in the room by 3-10' will make a significant change in the interaction with the room. The preferred location might actually be toward the side walls and forward of the speakers as measured front-back in the room, not that far from the spot you found the subs to be too strong. Possibly 1/2 way between that location and the speakers might be a reasonable compromise. When Nick does the setup, I would definitely do more tinkering to see if careful EQ, crossover, and phase settings in the DD+ software couldn't dramatically help the blend.

Some starting point suggestions for Nick based on some of the battles you've described: You will need to re-do the EQ with the new stack. Levels of all 4 subs should be the same, and the signal should come into one of the subs and use the thru connection so one controls the 2nd in the stack. The manual is a little vague so be sure to check the EQ is being applied to both subs at the same time. Power off your amplifier for your speakers, set the crossover for the subwoofer to ~200Hz, and run the software. First be sure to EQ any peaks in the response, paying particular attention to the range above where you will be crossing the subs out to 200Hz. Dips or downward tilt is OK, but knock down peaks at this point or you will be chasing your tail later. Next use a minimum required number of filters on the lower frequencies by using the full parametric adjustments. Now you are ready to turn on the main speakers and let the measurements come up with the subwoofer level turned way down so you know where you are starting. Set the crossover level you want to start with and now turn up the subwoofer level. Watch to see if any frequencies drop out as you raise the level. While the phase control will alter this, you also can change the crossover slope which will add more or less group delay to the subs and change the relative phase and interaction. As you find a point where they are extending the speaker's response and not fighting, now you can EQ the subwoofers so the combination with the speakers becomes more flat, not just the subwoofers. With the bass extension of the Stella's, you're always working with a large overlap range rather than a hard cut off. The combination at your listening position is what matters, not just the response of the subs. If the subs are sounding a little dominant over the main speakers or calling too much attention to their location, be sure to tinker with increasing the crossover slope (steeper) and/or making subtle changes to phase. Both of these changes will add delay to the subwoofer which will help the speakers be the more dominant factor subjectively.

While there are certainly plenty of adjustments to be made by ear and subjectively, those come after tackling the above matters and insuring the subs are complimenting more than fighting the speakers.
 

Ron Resnick

Site Co-Owner, Administrator
Jan 24, 2015
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Hello again Ron

I've been trying to remember the reasons we went Velodyne over Paradigm and I recalled a major one over the weekend.
The low pass filter of the Sub2 was/is set much higher than I wanted, given that the Stellas do have prodigious bass output.
This gave the impression of the Stellas' toes being trodden on by the Sub2 with an unwanted thickening to vocals and leading edges of bass. With the Velodynes we're able to roll them in lower down and let the Stellas do what they do best, which to my ears is anything above 25hz in room

That is interesting, thank you. I see in the Sub2 specifications that the lowest low-pass frequency is 35 Hz.
 

bonzo75

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Feb 26, 2014
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Mark, do you have experience integrating subs with panels, like Apogees? Using Trinnov, DeqX, or just analog.
 

NickHomeSound

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May 15, 2017
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Hi Nick, Did you happen to capture what sort of response you were able to get at the listening position with and without using Velodyne's internal EQ? Am I correct to guess the subs have a good rise to the measured response vs the upper frequencies in such a space and for the listening levels/preferences? Trinnov was mentioned, am I correct to assume you were considering an Amethyst for the system?

Hi Mark, I am visiting site soon to install the second set of 18's and plan to run both the DD+ eq and Trinnov for comparison with each other. We will be using the ST2 Hi-Fi at this stage to judge the impact of the Trinnov in the chain as much as the EQ performance. I am still running scenarios here in the demo room but my early findings are very positive.

I take on board your comments further down this thread and we are at the stage in this project where minor positional adjustments are valid. We spent a lot of time with the Sub2 and built on that with the first pair of DD18's prior to the stack. The current results are magnificent , really quite spectacular, but I am confident we can extract more.We build on it every time which is great.

Nick
 

Mark Seaton

WBF Technical Expert (Speaker & Acoustics)
May 21, 2010
381
141
390
47
Chicago, IL
www.seatonsound.net
Hi Mark, I am visiting site soon to install the second set of 18's and plan to run both the DD+ eq and Trinnov for comparison with each other. We will be using the ST2 Hi-Fi at this stage to judge the impact of the Trinnov in the chain as much as the EQ performance. I am still running scenarios here in the demo room but my early findings are very positive.

I take on board your comments further down this thread and we are at the stage in this project where minor positional adjustments are valid. We spent a lot of time with the Sub2 and built on that with the first pair of DD18's prior to the stack. The current results are magnificent , really quite spectacular, but I am confident we can extract more.We build on it every time which is great.

Nick

Good to hear Nick. The Trinnov is a very impressive and capable unit. It also has a near infinite range of adjustment. For both you and infinitely baffled, I would see what you can achieve in the lower frequencies first, as there are many adjustments available to increase or reduce or alter the effect on the upper frequency ranges. Obviously owners purchase speakers like the Stella's for their sound. I've found the best results by using various combinations of limiting magnitude correction in the upper frequencies, adjusting the number of cycles included in early reflections, adjusting the resolution/smoothing of the energy response, and of course the target curve adjustments. I don't recall if the ST2 implements crossovers & correction any differently than the Altitude, but there are of course many ways to attack the problem. Most important is to keep checking the before and after to confirm the results make sense as desirable.

Good luck with the experiments.
 

NickHomeSound

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May 15, 2017
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Good to hear Nick. The Trinnov is a very impressive and capable unit. It also has a near infinite range of adjustment. For both you and infinitely baffled, I would see what you can achieve in the lower frequencies first, as there are many adjustments available to increase or reduce or alter the effect on the upper frequency ranges. Obviously owners purchase speakers like the Stella's for their sound. I've found the best results by using various combinations of limiting magnitude correction in the upper frequencies, adjusting the number of cycles included in early reflections, adjusting the resolution/smoothing of the energy response, and of course the target curve adjustments. I don't recall if the ST2 implements crossovers & correction any differently than the Altitude, but there are of course many ways to attack the problem. Most important is to keep checking the before and after to confirm the results make sense as desirable.

Good luck with the experiments.

Thanks - the ST2 appears to be slightly different to the Altitude but I have good experience with that so the ST2 should be a powerful tool in this system. The plan is to limit the ST2 to the eq of the subs as much as possible and that is what I am playing around with right now. All good fun!
 

Mark Seaton

WBF Technical Expert (Speaker & Acoustics)
May 21, 2010
381
141
390
47
Chicago, IL
www.seatonsound.net
Mark, do you have experience integrating subs with panels, like Apogees? Using Trinnov, DeqX, or just analog.

The same rules apply, but being that dipoles load the room differently and often will have a 90 deg phase shift from a boxed subwoofer, there usually is some more tinkering to get the best measured and subjective blend. Obviously with only analog controls you are left more to placement and other creative adjustments in conjunction with treating the room. It's important to remember we can't possibly ever measure enough points in the room to get a 100% complete picture of what's going on. We're always sampling with measurements. Since a dipole loads/radiates into the room differently, some of the assumptions and solutions that worked with a conventional speaker might not hold true. Depending on how flexible or reflective the room boundaries are and even how much tactile energy is coupled through the structure affects the perceived bass power. A single point measurement can easily be off by 3-10dB vs what subjectively will sound balanced.

Sure, we can make some generic suggestions and add a laundry list of qualifications for that case, but it's better to understand what factors are contributing to the perceived result.
 

infinitely baffled

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Jul 2, 2015
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Good to hear Nick. The Trinnov is a very impressive and capable unit. It also has a near infinite range of adjustment. For both you and infinitely baffled, I would see what you can achieve in the lower frequencies first, as there are many adjustments available to increase or reduce or alter the effect on the upper frequency ranges. Obviously owners purchase speakers like the Stella's for their sound. I've found the best results by using various combinations of limiting magnitude correction in the upper frequencies, adjusting the number of cycles included in early reflections, adjusting the resolution/smoothing of the energy response, and of course the target curve adjustments. I don't recall if the ST2 implements crossovers & correction any differently than the Altitude, but there are of course many ways to attack the problem. Most important is to keep checking the before and after to confirm the results make sense as desirable.

Good luck with the experiments.

I really can't overstate how appreciative I am for your contributions Mark, also how happy I am that you are in conversation with Nick.
This bodes well for future cooperation, perhaps on one of your super duper installations; the sky really is the limit to where we go from here ?
 

infinitely baffled

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Also I've now done some reading on the Amethyst. ...Very, very intriguing
 

infinitely baffled

VIP/Donor
Jul 2, 2015
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Scotland
Quick update
Swapping 15's for 18's has been shifted to this Friday for a minor logistical issue at Nick's end.
I'll get him to post some pics once he's been
 

LL21

Well-Known Member
Dec 26, 2010
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Quick update
Swapping 15's for 18's has been shifted to this Friday for a minor logistical issue at Nick's end.
I'll get him to post some pics once he's been

Awesome...i have actually done a shoot out between the original DD15 and DD18 when deciding between the two...needless to say, i went DD18 as you can see on my signature (which actually reflects the now since upgraded DD18+). I hope you will be pleased with the DD18+ change, but bass reproduction is a very funny thing and hugely setup related...good luck and do let us know!
 

LL21

Well-Known Member
Dec 26, 2010
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Quick update
Swapping 15's for 18's has been shifted to this Friday for a minor logistical issue at Nick's end.
I'll get him to post some pics once he's been

BTW, if you end up keeping the new DD18+s...remember to update your signature...very cool to have a DUAL STACK of DD18+s!!!
 

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