subwoofers and panels don't mix

Hmmm... I know this thread is a bit old, just for others reading this and if you haven't gotten anything yet, I recommend the Hsu HO. I may have some of the problems described above but it sounds pretty darn good to me! Using test CD (Stereophile #2) and Radio Shack meter it wasn't hard at all to make it flat with some fiddling.

Try Tarzan (Phil Collins version) track 1 first minute, or Dark Side of the Moon track 1 first minute, then tracks 2 and 3... The Hsu with Magnepans will blow you away! Anyone else using these two together who thinks the Hsu is too slow? It could be, but I can't find a track where it is obvious. It just blows you away!!!! If someone thinks these aren't a great match, what is a track where I can try to detect it?

Mr Tennis - from your post 2 above - can you give me a specific track to listen to and what exactly should one listen for to identify that the woofer and panels don't blend seamlessly? I know when they sound really bad together - but when a system is pretty tuned (and has verifiable flat response at the couch from 20 to 200 Hz) - what exactly do you listen for?

The one thing I am aware of is some localization of the bass - which is obviously undesirable - I'm still trying to dial that in. I have a 20 ft cord and need a 25 to move it an inch from where it is, so I can't play with it too much right now.

Maybe its because my panels go so low by themselves, but I can't hear a thing that you guys are talking about!! I have the 3.6s. One thing I've learned since then is that my sub is *theoretically* not optimized for use with panels, the Hsu HO w/turbo has more venting length which slows down the sound. The current Hsu, which you can buy a couple of, should match even closer. But I honestly can't hear a thing you guys are talking about. Everything sounds awesome.

Oh - on the Rel only w/Maggies - some also use Martin Logan Depth as that is designed to be fast. But consider the new Hsu, which is not ported (and therefore not slow) at all. The ULS Quad Drive - crazy fast compared to my extra-ported VTF3HOw/Turbo. i have to think that would match really well.

Is there a physics term we can compare that tells us the 'slowness' of the sound?

Another track - with crazy dynamics and bass - The Serpents Egg, Track 9 (Dead Can Dance). You can't imagine it until you hear it.

I welcome anyone in the bay area to send a note through Audiogon and come over and try and show me what we are talking about and perhaps I can hear your system.

Ah, the term is "Group Delay". I am trying to find Group Delay numbers for some of the subs. It would be great if we could get:

Electrostatic panel itself Group Delay at say 300 Hz as refernce.

Group Delay from Sanders Systems integrated sub
Group Delay from Summit X Martin Logan integrated sub
Group Delay from Martin Logan Depth Sub
Group Delay from Hsu Quad Drive ULS-15
Group Delay from Stentor III REL
Group Delay from Stentor Studio III REL

Oh - and these things should be flat to 20, if I find out they roll off at 24, 22 or even 21 then I'm crossing them off, what is the point of all of spending that much money? Mine is pretty flat to 16.

Oh - and we have to put some sort of price limit on it, wasn't there a Krell Sub that used 30 amps circuits or something?

There is a guy 'CraigSub' on other forums and he is sub-crazy (in a good way!). Maybe I can get him to figure this out :).

Martykl and others - first sorry for not responding in a better amount of time. The research I set out to do was quite time consuming and while I didn't quite finish it I have enough to post. So - first of all I agree with a follow-on comment that group delay is one component of many, completely agreed and good crossover is critical, phase, placement, etc. I'm considering going bi-amping with 3.6s, well let me put it this way, I'm sure I am going to, but its a matter of what year. I really want to do it with 4 Pass 60A.5s, but that costs a car :)... So, the bryston crossover has gone up in cost, I think it used to be 2k and now its 3k, anyway it seems like what you really want to do is crossover from the active crossover, so now I need 2 3k crossovers (I'll probably get them used here), but anyway, agreed on all of that.

To answer a question, I do have some very very cool organ pieces, they aren't my goal, and I agree there is very little information below 35, even 45 Hz overall. But I'm in this to reproduce difficult sounds at the extremes. For far less cost I can not deal with the extremes from what I already have. I want the stuff in the middle and the extremes!!

However, after reading all of this info, group delay seems to make a lot of sense for critical listening of music. And lo me, I have an extra-ported sub when my sub company just came out with not only non-ported subs, but they are designed to be used in pairs, so I could have put one near each Maggie (and some say get three and put one near ceiling, don't know all the details). Anyway, the new Hsu stuff seems perfect for Maggies in some ways.

Oh - someone asked why I care strongly about it going to 20. First, not only do I want it to go to 20, I want it to go to 16! There is information you can feel. Look - there is mid fi, hi fi, and super-hi fi (alright, not a technical term). Similar to what I referred to above about going to extremes. If I already have speakers that do 35 pretty darn flat (although in my non-wall-reinforced setup I rolloff closer to 50), why spend 1 or 2k to go from 35 to 25 when hearing goes to 20 and feeling goes lower? Also on the 16 Hz, I've heard that there are harmonics from the 16hz tones that go up and change the effect. I don't know how exactly all that works.

Okay, but, if the newer 3.6s are 5.5k and the 20.1s are in the 11k range, and I spend 3k on a sub, I'm halfway to 20.1s! If I had 20.1s I would spend less time on sub forums :)... (Of course, given the right actively bi-amped solution).

Okay, so all that said, here is what I gathered:

Martin Logan Depth
http://www.avtalk.co.uk/showthread.php?t=15239
Group Delay
20 HZ 28 ms
25 HZ 30 ms
30 HZ 20 ms

Decent numbers, but very significant roll-off in output from 40 to 20 HZ......

VTF-3 MK3 w/Turbo (very similar to HO w/Turbo, which is what I have, but not as powerful. I would assume as port distance is the same, that the group delay should suffice for comparison.)
http://www.hometheatershack.com/forums/subwoofer-tests/5763-hsu-vtf-3-mk3-turbocharger.html

Group Delay
20 HZ 40 ms
25 HZ 15 ms
30 HZ 12 ms

REL Storm 5 (all I could find for REL)

Group Delay
20 HZ 9 ms
25 HZ 4 ms
30 HZ 2 ms

(So definitely faster that HSU w/turbo - but note not flat at all to 20! Using the Frequency Response Magnitude chart, Peaks at 40, and goes down quite strongly. At 40 it is 92 db, at 30 88 db, at 20 84 db, at 16 81 db. The HSU is within 2 db flat to 16 HZ!.)

JL Fathom - not in my list but many talk about it.

Couldn't hack it flat to 20 HZ, let alone 16!!

But here are its Group Delay numbers anyway:

Group Delay
20 HZ 33 ms
25 HZ 24 ms
30 HZ 10 ms

There was a velodyne SPL-1200 MK2, but it was so fallen off by 20 it didn't interest me, and the group delay was high (60 ms at 20 HZ) so forget it...

Martin Logan Depth

Group Delay
20 HZ 28 ms
25 HZ 30 ms
30 HZ 20 ms

Decent numbers, but very significant roll-off from 40 to 20 HZ......

So my comments on that based on preconceived notions is that I'm very dissapointed in the Martin Logan solution as I would have thought they would have focused more than anyone on Group Delay, I expected bad numbers for Hsu/Turbo models which came through - though not bad as you get away from 20, its really the super low bass that is slow, and REL is indeed king of this issue. I'd like to get this number for the new ULS-15 Hsu, but can't find it. Several people say it is 'low' but no testing and numbers I can find. I really think that might be the one to have.

The only thing with the REL - and maybe just get next model up is it doesn't go as low as it could. People are saying on another forum that 2 ULS-15s are flat to 5 Hz. Woo hoo! Now that is something.

I know this isn't music, but the movie 'Push' has some of the best bass I've ever heard integrated into a movie. And I mean really low bass. I think flat response is a bit low, raise the level of the woofer (assuming you're crossing over at 60 Hz or below, mine is at 50 Hz), just move it up a tad.

The scene where he walks into the restaurant and moves the salt (water? can't remember) pouring out from the waitress to the person's food/drink with his hand - that should be very audible. If you adjust the woofer up a bit (not too far!) so that you can clearly hear that as loud bass, then the movie will have a ton of really really really really low bass that is well done - not overdone. I'm pretty sure we're talking 20 - 35 Hz bass, that is some serious soundwork they did. If your system doesn't go to 20, you'll be missing out! :)

Hey guys, I ran across some interesting developments here and thought they might bear out on what we are discussing.

Hsu has a new subwoofer (not so new now, but newer than the latest post above) and it might help us with panel integration. It is called the VTF-15H and while it is a bit bigger than my VTF3-HO (11.5 inch woofer vs 15) that is not in particular what I care about.

It has a 'sealed mode' (meaning --> quick/fast) *and* it has extensive tunability features that may make it so we can tune it to a more panel-friendly state. I will not be acquiring one anytime soon :), so someone else who owns one or who can somehow borrow one and who has 1.7/3.6/etc. will have to test if they feel so inclined, but this looks very promising.

It has an alterable Q Factor, as well as an alterable EQ. Well, anyhow, I'll just let this owner explain it:

http://forum.hsuresearch.com/showpost.php?p=78790&postcount=88

(Please do read that - that is the point of this post.)

And here is a professional review:

http://www.hometheater.com/content/hsu-vtf-15h-subwoofer

So, will this help? It very well could be!!

I'd love it if someone who really knows subs could read all the literature on the tune-ability of it and comment - maybe it is all just eq, or maybe it can change other properties of the sound to make it blend with panels better. And the sealed mode will help, someone mentioned that above - the VTF-3HO that I have doesn't do that, but this new one does.

And - I think we are a funny group, crossing over at 45 Hz (at least for 3.6/3.7 owners), so our sub needs are different than most. I think what this newer sub can do if you are crossing over at 70 or 80 will definitely be very very significant (1.6/1.7, other lower-bass e-stat owners)!

I'd believe that - a pair of F212's seems to be the current state of the art from what I've read, never heard them. The fun part of the Hsu 15H is they are 850 each! Basically free compared to the JLs :).

I still think its crazy that we are doing this for 16 - 45 Hz, but on those few tracks, it sure does make a gigantic difference!