11-23-11: Lightminer
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....
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! According to the review of twin JL Gotham G213s in Issue 26 of ToneAudio, the infrasonic information conveyed by the subwoofers that go lower than 20 Hz is relevant to any kind of music, and recreates the room ambience that so often distinguishes the sound of live music from reproduced. The review says in part:
Two subwoofers does not mean that Im shaking the rafters with the Gothams. Quite the contrary. It allows me to run them at lower levels and to produce a more refulgent, satisfying sound. But that sound can be hard to pin down because, as I tried to suggest above, the Gothams are often out of the picture when no real deep bass frequencies are present. But they are producing ambience all the time. Turn the two subs off and it sounds as though the mains shrank in size and volume even on a Bach solo guitar piece. Weird? Definitely. But impossible to refute. There is apparently information in the subsonic region that fills out the sound of a concert hall. Once youve heard it, you cant go back.
Now I'm dying to get a pair of sealed subs that'll put that sensation in *my* listening room. |
The problem with matching subs to panels is poor transient response in many subwoofers, excessive driver excursions and the problem of the sub sounding best in placements that doesn't mate best to loudspeaker in the position sub sounds best in. With panels 2 or more large cone limited excursion drivers match best. Multiple sub bass sources again are the better match. |
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! |
11-21-11: Lightminer
Hsu has a new subwoofer ... called the VTF-15H ... [which] ... 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.
SVS also offers this feature in their top line box sub, the PB13-Ultra. It has three ports and three plugs, making for four lower extent rolloff profiles. The 13" driver itself is massive and built for very long throw--reminds me of the JL driver. Follow the live link to see the description, the pic of the driver, and the four frequency response curves from sealed, one, two, or three open ports. It's been five years since this thread was started. In the last few years, I think several sub contenders have come out with more configurability, speed, and power to mesh with panel speakers. Candidates include JL, the Velodyne DD+ series, the top line Hsu's, and the SVS's. I've heard a pair of JL Fathom F212s mated to a pair of Magnepan 20.1s and it was seamless. I heard it for a couple hours with a professional setup driven by Ayre electronics and Transparent cable throughout. |
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)! |
Soundlabs are reviewed as having very good realistic bass, so a sub should not be necessary.
However before I got the Soundlabs I was going to try out a Klipschorn bass unit that I managed to get hold of - my theory is that it would make the ideal sub I agree with Johnk - stay away from bass bins - far away. Gordon Holt used Soundlabs (very fast) for many years before switching to ATC speakers (fast with panel-like mids and more dynamics). An 0.1/15 ATC sub will probably integrate with panels as good as if not better than most anything else - only problem is they are $7K which is like twice what a good JL subwoofer costs. If budget constrains you then check out a JL F112 first and see how that sounds (it is great value for a tight/fast sub). On another point - how would you stop the bass from a poweful sub (like a JL or ATC) from interfering with the panels - surely the giant panel surfaces will be influenced by the air vibrations in the room. What I mean is this - when I play music loud then I can feel all the surfaces vibrating as they respond to airborne LF vibrations. Obviously a woofer with a huge magnet will be tightly controlled and remain unaffected - this is unlikley to be th case for a huge surface area of a panel in a relatively weak force field. |
Somewhat further OT here:
NHT's lifestyle "woofer" system is being closed out at Audio Advisor (I get their mailers) @ $300 per. This isn't really a "subwoofer", but it puts two 10" drivers in a very slim sealed box (app 6" deep) with IIRC a 200 watt amplifier. Max extension is something like 38hz @ unspecified spl/unspecified THD.
Observation: Since the narrow cabinet puts the front of the woofer 6" from the wall, cancellation effects should be minimal.
Observation 2: Max excursion of the drivers is unspecified, but can (presumably) be limited by employing multiple units in the room.
Question: If you scatter 4 - 6 of these units in your room ($1200 to $1800) how do you suppose performance would compare with conventional subs in the price range?
I'm not in the market, but the question crossed my mind and I wonder what you guys think.
Marty |
You would need a massive BLH sub. Or 2 stay clear of klipsch w bin yuck. Or maybe consider a 31.5 in super woofer in ported cabinet. The Fostex 31.5 in was amazing transient reponce very low excursions massive cone area so matchs up great with planars or stats. |
What about the Wilson Benesch Torus "infrasonic generator?"
I have yet to hear them, but from what I understand the push pull design and extremely low mass (half an ounce) of the 18" driver supposedly makes it extremely fast, and would seem like a perfect match for stats.
Can anyone comment on them? |
Only a horn has the transient speed and "air" to keep up with a panel????
Any responses? A horn subwoofer would need a huge chamber. If it were folded and made of concrete (so the walls did not introduce distortion) then it might work but we are talking dimensions of 30 feet or so. If you are thinking ported or TL design then the transient response will not be as good as a sealed box. |
Has anyone experimented with horn subs?
I have recently acquired some Soundlab M1's and still have a long way to go to get the total system working properly. One aspect is the bass weight. Soundlabs are reviewed as having very good realistic bass, so a sub should not be necessary.
However before I got the Soundlabs I was going to try out a Klipschorn bass unit that I managed to get hold of - my theory is that it would make the ideal sub. Only a horn has the transient speed and "air" to keep up with a panel????
Any responses? |
Stereo subs are the best and crossing them over where the mains leave off is a must. Having them in the same plane as the midrange driver panel and facing forward will also increase the seemlessness. Placing the subs on a support platform also improves the definition. |
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! :) |
Lightminer,
For your goals, I suspect that a pair of SVS Ultras in sealed (or maybe 16hz tuned) mode would be hard to beat. Remember that the additional sub provides 3db (more like 5db in my room) output, so read the distortion/clean output graphs at lower output to maintain "apples to apples" comparisons.
Also, bear in mind that the output at, say, 50hz from your Maggies will NOT sound the same as the 50hz output from a sub. I can't say for sure which you'll prefer, but I'm confident that you'll hear a difference. If you EQ the subs, I'm nearly 100% sure you'll hear quite a significant difference.
Good Luck
Marty |
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. |
Agreed.
I'm just finding it difficult to reconcile the published numbers I see with what I actually hear. I'll eventually order a pair of SVS 13" Ultras and use them in sealed mode - pretty low distortion from a pair and GD stays below 30 at 20hz. The cost of a pair is still below that of one JL113, so my sense is that this is a good value play. At least as far as upgraded subs can represent good value for me. I guess I'll have a better idea when I get 'em in place.
Marty |
Marty,
Indeed, it is fair to say that the importance of low group delay increases
significantly as you go above 40 Hz. However low distortion remains
important right down to 20Hz because an 80 Hz harmonic of a 20 Hz signal is
likely to be quite loud to your hearing even if it is of the order of a mere 1%.
(This is because hearing sensitivity increases dramatically from 20 to 80 Hz.)
So if you have high group delay and a sub which puts out say 100% THD at 20
Hz then you might be rather concerned about what this is doing to the
unwanted distortion harmonics from non-linearities in the design. |
Two more group delay observations:
First is inconsistency in test results:
If you cross check AVTalk and Hometheatershack you will see differences in the test results of the same model subwoofer (these may look smallish at a glace) which prove greater than the delta between differing makes & models. In fact, HTshack tested 2 samples of the SVS 12NSD and got significantly different GD results.
Second is Shadorne's illustration of GD's impact at 20hz:
While the GD test results really diverge at this low frequency, they tend to converge significantly as pitch rises. I wonder if the lack of really low frequency program content tends to obscure the audibility of a sub's GD capability. At least, the program material I used in my listening tests.
Marty |
My conclusion is that careful set-up (probably including EQ) likely
trumps specific sub performance. IOW, I suspect that the specs we use are
measuring stuff I can't hear (or, at least, hear very well). YMMV. You have a good point. Room modes and slow RT60 decay times of more than 1 second will also have a huge influence on the bass response. In a sense, room modal reverberation is a form of repeated/delayed bass cycles that can actually last longer than anything the subwoofer does due to a port or high group dalay. The only thing I would add is that it is all cumulative...add a slow subwoofer with large group delay into a modest highly modal reverberant space and the bass will start to dominate and sound boomy and disconnected from the panel's beautiful light midrange. So if you have a large space that has a great RT60 with very fast decay times in the bass then you might not care too much about the subwoofer group delay. BTW Large classical concert halls sound best with RT60's up around 1.4sec. Loud rock and big band in a normal sized studio monitoring room sound better with RT60's around 0.4sec. So the room as well as the genre play a big role too. |
Shadorne,
I understand your point entirely. Now mine:
I recently heard the JL 113 Fathom (low group delay) set up with the
Maggie 1.X (don't recall the current designation) at a local dealer. After an
hour, I had the following observations:
1) The bass sounded no tighter, quicker, or less smeared than my (high
group delay) SPLRs.
2) Mid-bass and mid-range didn't sound more articulate.
3) Discontinuity between planars and subs was evident to me (I attribute this
to careless set-up).
4) The system was more dynamic sounding than mine.
5) This was a different room/different source & amplification/ different set-
up regimen than I use at home, therefore an imperfect test.
However, I concluded that the lower group delay wasn't OBVIOUSLY audible
to me in this set-up, as I expected it might be. Neither was the improved
distortion performance (The JLs produce far better distortion specs than my
SPLRs). My conclusion is that careful set-up (probably including EQ) likely
trumps specific sub performance. IOW, I suspect that the specs we use are
measuring stuff I can't hear (or, at least, hear very well). YMMV.
Marty
BTW, once I figure out which subs make the most sense (I wish I had data on
more models) , I'll probably replace the SPLRs (if only on principle alone). I
want lower GD in my system, even if the effect isn't dramatic. Same for lower
distortion. To be clear, I'm not saying better subs don't sound better. I'm just
saying that IME better set-up (including EQ if that -as is likely- proves
necessary) is more obviously beneficial to my ear.
Further, for the OP, I suspect that great subs won't fix his problem. Good
subs, properly set up, just might.
Finally, thanks again to you, Bob and Drew for pointing the way toward betetr
bass performance in my system. Your advice has been invaluable. |
Firstly, I like Marty I don't understand the preoccupation with flat to 20 Hz - most rooms have 10 db SPL peaks and troughs in the bass and furthermore room boost always causes a rising output in SPL as you go lower with frequency.
Secondly, the reason for a fast bass repsonse (low group delay - no extra added cycles) is to avoid masking the transparent panel midrange with delayed or smeared bass response. A port is adding a signal delayed by 1 cycle and at 20 Hz this is 50 msecs...a lot of midrange music can occcur over 50 msecs, as that is equivalent to 50 cycles of 1000 Hz - and a loud bass sound can reduce your ability to hear the midrange details (masking) |
Lightminer,
Are you using your system for HT as well as music? Are you a pipe organ guy? If not, why worry about ultimate LF below 25hz. In my collection of >5,000 records and cds, I can only think of a few that go below 30hz. I only mention this because there are tradeoffs in choosing subs and the first one I'll give away is extension.
BTW, I can't imagine that you'll miss the difference in bass performance between EQ'd subs w/ your 3.6s and full range 3.6s. Both will "go there", but they'll sound quite different in terms of "impact". I personally have little issue with timbre (my subs are actively crossed at 74hz). I assume that this is because timbre becomes less meaningful as you descend in frequency. At 25hz, you feel it more than you hear it. I may be less sensitive to timbre issues higher in hz near the x-over than some other folks, but I don't hear the timbre change im my set up; even in the lower registers of electric bass or piano where fundamentals may fall in this critical area. However, this is a classic YMMV.
AVTalk.com and Hometheatershack.com are the two subwoofer distortion & group delay databases I know of (Thanks Shadorne and Bob Reynolds). None of the data you seek is on either site, but there are several REL model test results vailable. General rule for REL = great group delay #s, ugly distortion #s. SVS subs seem to offer a nearly unmatched balance of distortion & group delay performance (if you value both equally), and they do so at a comparatively low price.
Marty |
I may sound like a broken record here: Room analysis, PEq, felexible x-over. I've used a Velodyne SMS-1 sub controller to seamlessly integrate a pair of Velodyne SPLR 800 subs with Maggie SMGs. It took a lot of time and a lot of tweaking, but I can't hear the crossover at all. Let me emphasize, I've always loved the IDEA of hybrid speakers, but, to my ear, even the best (IMHO - Eminent Tech) have had issues with the planar/dynamic x-over.
Using the SMS room analyzer, you can easily see how dipoles differ from forward firing speakers throughout the bass. The nature of the response irregularities in panels makes integration a real challenge - but it can be done.
IMHO, the key to good sub/speaker is smooth on-axis FR around the x-over point, so I follow the following procedure:
1) Use the room analyzer to find a smoothish chunk of bass and start with a frequency in the center of this area as your x-over point. Be sure that this "smooth area" is reasonably balanced w/the rest of the spectrum. A smooth plateau at + 15db doesn't work very well. You may have to move the sub(s) around the room a bit, 'til you find a good result.
2) Flip polarity (this will usually kill the primary suckout quite effectively) to see whether + or - works better.
3) EQ around the x-over point for further smoothing.
4) EQ below the x-over for best balance of smooth vs extended deep bass response.
IME, this procedure will get excellent results from subwoofers with a dipole, unidirectional, or omni speakers (I've tried all three).
Good Luck
Marty
BTW - I really doubt that your choice of subwoofer model is critical - looking "fast vs. slow" isn't likely to help. IME, integration trumps sub performance. I chose the Velos because of size. There are several other models at/near their price that return far better specs (group delay for speed and distortion for clean output) and will very likely outperform them. Yet, I still get great results despite the mediocre subs I use. |
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 :). |
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. |
Lightminer,
I would suggest that Shefield Drum track will highlight most of the reasons panels and subwoofers don't mix. Drums are some of the hardest sounds to reproduce convincingly, although other percussion instruments (like the piano) will work well too...Dave Grusin is a good choice.
My guess is you need a critically damped subwoofer which generally means a very large motor magnet structure within a sealed box and not the usual boomy kind (known for total movie noise capability). This means the woofer goes directly to the rest position when the signal drops to zero without any overshoot or additional resonant oscillations. Remember the panel will have good transient capabilities in the sense that it has very little stored energy... |
the issue is not localization of bass but rather the timbre.
i would suggest that you listen to dave grusin, "keep your eye on the shadow", on sheffield. i have a cd called PRIME CUTS, and it is track 8.
panel bass and cone bass sounds different, just midrange reproduced by a cone and a planar driver also sounds different. |
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.
|
Mrtennis,
I will not be exhibiting in Las Vegas in January, though I plan to ogle & schmooze so we might bump into one another in the hallway. That show is geared towards manufacturers and dealers finding one another, and frankly I'm not looking for dealers. Besides RMAF is less expensive and imho a better show.
Duke |
hi duke:
hearing is believing. if someone can demonstrate a stereo system with panel speakers and cone woofers which blend seamlessly, i'll change my opinion on the subject.
i will not be at the rmaf. i will be in las vegas in january. might i see you there, again ? |
Thanks for the information, Mrtennis. I appreciate your taking the time to call Magnepan. You know, maybe just maybe having a reviewer interested enough to call 'em up will help push the project forward.
If you'll be at RMAF, it would be nice to see you. I'm in room 1100. Not expecting to win you over, needless to say!
Duke |
hi duke:
i called magnepan today. the woofer that i heard at ces 2007 is not in production yet. it is still a prototype.
shadorne, thanks for the reference to abraxas speakers.
i think that for now i will live with the limitations of the magnepan and not purchase a subwoofer.
hopefully the martin logan clx has "enough" bass and is not too expensive. |
Mr T....this may be what you are looking for Emperor (Check under products for Emperor loudspeaker) Impractical perhaps but since when has esoteric Hi-Fi been practical. 20 electrostatic "woofer" panels should get you 110 db SPL down to 20 Hz! |
Harry Pearson and RF Gumby got very, very different results with the Carver subwoofer mated to Maggies. I suspect that neither one is deaf, and that neither one is incompetent, and that neither one is dishonest.
So, what happened?
Different room acoustics is what happened. The Carver's slightly pumped-up deep bass worked well in Harry's room, but not in Gumby's.
The room's effect is huge in the bass region - hence my preference for systems that are inherently room-friendly and have a wide range of adjustability. Dipoles are inherently room-friendly in the bass region; that is, because a pair of dipoles has the inherent in-room smoothness we'd expect from four monopoles (two of which are out of phase), their bass doesn't vary as much from one room to another, nor from one location to another within a given room (except of course if you stand in the side nulls).
Mrtennis, can you tell us the price of the 40 Hz Maggie subwoofer that you heard?
Do you know if Magnepan has plans to develop a larger version? Bass comparable to the 20.1 would be nice, assuming price isn't prohibitive.
Duke |
i owned the centaur minor. as soon as i heard the first note, it sounded like two different speakers.
the problem is a lack of coherence. a ribbon midrange and cone bass create a discontinuity. i have always been able to distinguish the difference between cones and panels.
i believe i can identify a cone driver when it is combined with dissimilar driver.
it may be possible to disguise the presence of a cone if the main speaker is not crossed over to the sub. if the sub rolls off with a steep slope at say 45 hz, you may be able to blend the two driver types creating a a seamless blend for most listeners. however, an experienced listener will probably detect the presence of a cone.
personally, i will wait for magnepan to design a panel driver capable of producing frequencies below 40 hz. |
Shadorne has a great point. Another thing I found during the Maggie subwoofer debacle is that Maggies seem to be very linear in output power (or sound pressure) relative to input power from the amplifier.
Subs (and most dynamic speakers in my experience), tend to
be more logrithmic, which happens to be more like the way we hear. Not that the comparison between panels and dynamic speakers is bad, just that they are different.
That difference seems to lead to an imbalance between
panel level and sub level with different source material
and differences in recording levels and different levels in individual songs. I found myself getting driven crazy adjusting the sub volume versus panel level even within
1 song or when I changed albums. That level problem even more than the dissimilar speaker mating problem led me to give up on the process and just listen to the panels full range.
Best of luck, I hope you have better results in your quest.
An electronic crossover is helpful, but has other issues that seem to go along with it (phas and staging issues mostly).
RFG |
Just a thought - having never experimented - but could the issue be related to dynamics? A panel is not known for punchy dynamics (typically they compress audio signals and are preferred for classical listening)
...yet most subs are evaluated on their dynamic impact.
My suggestion would be to use an adjustable audio compressor on the sub signal so the sub can work in a "balanced" way with the rest of the audio frequencies from the panel....limit the dynamic range of the sub to match the panel.
A balanced sound will be correct at a variety of listening levels/dynamic ranges rather than over a very limited range or sweetspot.
This works if we assume that the panels bass roll-off remains consistent at different volume levels (like cone speakers generally do)....if the panel roll-off is also level dependent then I can't see a way to ever achieve a proper match. |
I became really frustrated with trying to integrate subs with Maggie 3.5R's. About 6 months of trying with Carver true subs (they were poor, slow and had horrible overhang).
I spun them off for a brutal loss and moved on.
They literally had a delay before playing and 1-2 seconds of overhang afterwards. I guess when they glued a 4 pound hunk of steel to a passive radiator to calm it down that's what you should expect.
So I went on to smaller Velodynes (can't remember the model). Mass loading and spikes helped, but still seemed far too dissimilar to be acceptable. In either case with the Carvers or Velodynes, I tried every possible combination of electronics, internal XO and external Bryston XO, low pass/high cut frequencies, running the panels high passed and full range, different cabling, etc. None were acceptable to me.
I've heard REL subs in a few situations with Maggies and they were better, but still not great. I can say that I prefer 2 subs far more than one, regardless of location and implementation. Also, generally, that smaller the sub driver, the better luck you'll have.
I really can't believe that Harry Pearson in Absound recommended 3.6's and Carvers- shockingly bad IMHO. That would have been the point I stopped listening to reviewers as any reference other than anecdotal.
RFG |
Although it's not really a subwoofer/ribbon combi, I feel that Apogee has managed to combine a cone/ribbon succesfully around the '90's. I'm not saying my Apoge Centaur Major is perfect - it just isn't. But the transition between woofer and ribbon is flawless, even considering they're crossed at a remarkably high 350 Hz. Apogee has done several things to achieve this. The woofer is placed in a closed enclosure, which helps transients. The centre of the woofer is on the same height as the centre of the ribbon, so the woofer is not, like for instance Martin Logan, placed under the ribbon, but beside the ribbon. That also means the woofer is placed about one metre above the floor.
So all I'm trying to point out is that it is possible to succesfully combine a cone woofer and a ribbon/planar. It's just a lot of hard work. |
Mrtennis,
As a SoundLab dealer, for many years I believed that cones could not possibly blend well with panels.
But is it panels and cones that sound so different from one another, or is it really dipoles and monopoles?
I've spent time with maybe a dozen different dipole panel systems and a half-dozen different dipole cone systems. I'd say that dipoles tend to have very similar bass (below 80 Hz), whether produced by a panel or a cone. Maybe not identical, but very similar - close enough to blend well if done right.
What I have presented in my preceding post is a rough sketch of a technique for getting dipole-like in-room smoothness from a judicious array of four monopole subwoofers. The line-source vs point-source discrepancy can be addressed at the same time by the four-piece subwoofer system (I can explain how if you'd like).
While a dipole panel or even cone subwoofer might be the theoretically ideal solution, how much would it cost for a dipole subwoofer that will give you significant bass extension and enough headroom to keep up with Maggies driven by a powerful amplifier?
Since you raise the question of cones & panels blending and I'm arguing that it can be done if done right, I hope it's alright for me to post links to online commentary about my prototype subwoofer system, one from a Maggie owner and the other from a Quad owner. This doesn't constitute proof of course, but I think it does constitute evidence:
http://www.audioasylum.com/forums/MUG/messages/108124.html
http://www.audioasylum.com/audio/speakers/messages/247336.html
Let me know if you have any questions.
Duke |
hi duke:
as a dealer of soundlabs, wouldn't you think the problem of integrating dissimilar drivers is one of coherence.
regardless of where and how many cones you place in a room, a cone does not sound like a ribbon, electrostat or planar magnetic driver.
magnepan has the right idea. at ces 2007, i heard a prototype magnepan woofer. coherence is not a problem with such a driver.
it would seem that the best sybwoofer for a panel is another panel, rather than a cone. |
Wilson Benesch Torus will do the trick. Lightning fast. - Jim |
I used to think that the problem in trying to blend a subwoofer with a planar was primarily a transient response issue (see my post above, dating back about 15 months). Now I believe that it is primarily a room interaction issue.
By way of introduction, consider the case of a single subwoofer located somewhere along the wall in front of us. There will be one path length from the subwoofer to the listener's ears, and then there will be another path length from the subwoofer to the wall behind the listener, thence reflecting back to the listener's ears. At the frequency where the difference in these two path lengths is equal to one-half wavelength, the energy reflecting off the back wall arrives 180 degrees out-of-phase with the direct sound and the result is a cancellation notch. At the frequency where the path length difference is equal to one wavelength, the reflected energy arrives in-phase and the result is a reinforcement peak. There will be other room-interaction-induced peaks and dips from other reflection paths, and from bass standing-wave modes if the listening position is near a node or an antinode. We can re-arrange these peaks and dips somewhat by moving the subwoofer or the listening position or both, but we cannot eliminate them by placement alone.
Equalization can smoothe the response at one listening position, but may well make it worse at other locations within the room. Whether or not equalization is the right choice depends on your listening style. I will be focusing on an acoustic rather than an electronic solution.
Now note that the problem is not that there are too many of these room-induced peaks and dips; rather, the problem is that there are too few! If we had a large enough room that the peaks and dips were more plentiful and therefore averaged out over short intervals (the ear averages out the sound across roughly 1/3 octave intervals called "critical bands), we'd have subjectively much smoother bass. It is the wide spacing of room-induced peaks and dips that makes them audible and objectionable in the bass region.
Research published in the Journal of the Audio Engineering Society by Todd Welti et al indicates that spaced mulitiple low frequency sources in a room will give smoother in-room bass than a single low frequency source. Briefly, the individual peak-and-dip patterns from each distinct low frequency source is unique enough that the average of several of them is considerably smoother than any one of them could be. We might say that having spaced multiple low-frequency sources "de-correlates" the low frequency sound field, and that is desirable.
Here's a link to a Harmon paper written by Todd Welti. It's not a technical as his AES papers, and is geared towards home theater applications, but the low frequency acoustic priciples apply to two-channel reproduction as well. In case you don't feel like reading the whole thing, Welti concludes by advocating four subwoofers arranged in one of two symmetrical patterns - either in all four corners, or in all four midwall locations:
http://www.harman.com/wp/pdf/multsubs.pdf
How does this apply to dipole speakers? Well, a single dipole can be thought of as two monopole speakers back-to-back separated by a baffle, with the phase of the rearward-facing monopole reversed. So we might expect a dipole speaker's in-room bass smoothness to be comparable to what we might get from four monopoles. In fact, James M. Kates wrote a paper entitled "Dipole Loudspeaker Response in Listening Rooms", which clearly shows the superior in-room bass smoothness of a dipole compared to a monopole. Many dipole owners can attest to the superior bass pitch definition of dipoles, which can be attributed to their much improved in-room smoothness.
So when we try to match up a single subwoofer with two dipole speakers, we are trying to match up systems that have significantly different in-room characteristics. And in most cases the mismatch sticks out like a sore thumb - the low bass simply does not have the same characteristics as the rest of the spectrum. Those who have tried two subwoofers with dipole speakers seem to have a much higher rate of success, as we would expect if the foregoing discussion has merit.
The approach that I advocate is to use four small subwoofers and scatter them asymmetrically around the room. The reason for the asymmetrical scattering is to generate greater dissimilarity in the respective in-room peak-and-dip patterns from the four low frequency sources. I got this idea from Earl Geddes, and use it in a commercial system with his permission. Earl did a computer simulation study comparing four asymmetrically-scattered subs against four symmetrically-placed ones, using one of Welti's recommended configurations:
http://www.gedlee.com/downloads/sub%20study%20.pdf
One final characteristic that the subs should have for this asymmetrical scattering is a steep-slope low-pass filter, so that none of the subs will betray their location by audibly contributing up in the midbass region. Also, good dipoles like Maggies and Quads already have superbly articulate midbass and the last thing they need is a subwoofer mucking that up.
While I do build a packaged multi-sub system (specifically intended to blend well with Quads and Maggies), these basic concepts can be incorporated into a multi-sub system that anyone can assemble themselves from subwoofers that are readily available on the market. The point of this post is to indroduce a new way of thinking about the problem of integrating subwoofers with planars, focusing on room interaction instead of subwoofer transient response.
Duke |
I have been using MGllla's with a Vanersteen sub for a long time. The vandy is just as fast as the maggies, if not faster. The combo is seamless with added benifit of the bass panels being cut off at 80hz, letting the middrange panels open up. Panels and subs can and do work well together, just finding a "fast enough" sub is the trick.
Bill |
"i have been advised to use only a rel with a panel speaker."
Seems like strange advice to me. There are some very good and fast subs around, and yes, they are not all REL! |
hi lightminer:
thanks for your comments re the hsu.
i have been advised to use only a rel with a panel speaker.
i have not heard the hsu with magnepans. magnepan has designed a woofer, based upon the mg 20.1, for use with other magnepans. this panel woofer goes down to 40 hz. it is not a "sub" woofer, and perhaps magnepan will design a panel driver which goes below 40 hz. if so, problem solved. |
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? |
Thanks a lot, Ojgalli. I just spent ninety minutes dialing in my sub using the Rives CD2 and the Radio Shack meter. I forgot just what this would do to my two channel.
You are the coolest. |
I have Ribbons/Hybrid the Superslim 1800se speakers from www.ambiencespeakers.com.au and the Castle Classic Active Subwoofer, it required patience and time to get them perfectly well-integrated, seamless spectrum. I think ribbons and dynamic Sub Woofers can match perfectly well, it is a matter of adjusting and regulating. Best, Antonio Machado. |
"crossed over at 35Hz" !!
IMHO, a subwoofer that can't go higher than that, unloading the main speakers, is just as bad as one that can't go lower than 35 Hz. Sometimes audiophiles seem to get into a contest as to whose SW is crossed over lower. It reminds me of a Hoot Owl that lived at the nearby Audibon park. It would hoot back at you IF you hooted at a lower pitch. The hoot would go back and forth until the bird was as low as it could go. |
