mas Posted January 31, 2007 Share Posted January 31, 2007 1. Suspended from the ceiling???.............................are you crazy? 2. Does your answer indicate that there are subs out there that could and would blow out a candle? 3. l like side-by-side closely packed acting like one larger unit. I think this translates to "more bass" doesn't it? 1. That is exactly what Ingvar Öhman's paper suggests - which would be correct placement for what he suggests and states (albeit over simplistically). Don't worry...I wouldn't I mess with it either. 2. While I haven't ever been concerned with using that as a criterion, I have encountered plenty of speakers whose port volume could easily accomplish that fact, and I am sure the Dafos drum beat could easily invoke that response in quite a few of the larger subs. But I will admit that I am not going to pursue the issue... [] 3. Yes, The coupling is specifically intended to yield higher SPLs with a minimum amount of interdriver artifacts. If you simply want more gain, this is the way to go. But personally, if you are going to use two subs, I would use one unit to reproduce the lowest octave and the other to reproduce the next lowest octave. You will get near the same SPL without the associated artifacts and with lower distortion - a quality that I personally value more than the slight increase in gain and greater distortion. But hey, its your choice, and I am confident you will make a choice that you like. So have fun. And while I do not want to reopen the can of worms (but I guess I am doing!!!), I would amplify the earlier suggestion that you should easily be able to recover most of your cost of the Velodyne, and then you would be able to purchase an even more powerful single sub - be it a Hsu or even an SVS (if value/money is the primary focus) or... heck, the more powerful Velodynes, Paradigms, or even Sunfire (based on theEar's recommendation - as I have never been a big BCarver fan) or, heck, Ear has mentioned several others in that class which I am sure he would again be glad to suggest. And wouldn't your wife like the idea of only one sub instead of two??? This of this approach as having several strategic advantages![] ...A single more powerful sub would be my first choice* with 2 reproducing adjacent passbands my second choice, but this is about what you want! So please have fun! Edit for clarity: For music I would recommend stereo low pass for the subs (especially to match the efficiency of LaScalas KHorns or Jubilees), for HT with an LFE, I would recommend two smaller subs reproducing adjacent passbands or one larger sub. Quote Link to comment Share on other sites More sharing options...
cjgeraci Posted January 31, 2007 Share Posted January 31, 2007 Previously did the two (and three) subs thing. Colocated and different portions of different rooms. Calibrated and phase, etc., etc. etc. Just because you have more subbage (2 subs), doesn't necessarily mean that its better. Get the VTF3 Turbo and sell the Vel. If you really want (or somehow need) to keep both, stack them or at least colocate them. I like MAS idea of splitting the bands to play to strengths. Or take the above as just "suggestions" and do what you please. Carl. Quote Link to comment Share on other sites More sharing options...
Roc Rinaldi Posted January 31, 2007 Author Share Posted January 31, 2007 Thank you Carl & mas. I really am listening to your advice. If you dedicate a different frequency range to each sub, sometimes won't onoly one sub be working? I only wanted to keep the velodyne in order to achieve even more bass but I don't want boomy. I want clarity, low or no distortion, and at the proper times, lots of vibrating bass. (led zeppelin you know) Thanks again. Quote Link to comment Share on other sites More sharing options...
DrWho Posted January 31, 2007 Share Posted January 31, 2007 Edit for clarity: For music I would recommend stereo low pass for the subs (especially to match the efficiency of LaScalas KHorns or Jubilees), for HT with an LFE, I would recommend two smaller subs reproducing adjacent passbands or one larger sub. Sorry, your edit wasn't big enough [] I really need to find this article, but I remember reading about some research Bell Labs did in the 70's indicating that stereo subwoofage was "required" for an "accurate" sound stage. Even if you aren't able to send a true stereo signal to each sub, having one on each side of the room works wonders in balancing out the image. With a single sub off to one side it'll sound like the other side is a bit hollow sounding. I actually find myself leaning in the chair... [] Right now I've got 5 subwoofers to my disposal, all with sub 20Hz capability (4 of them having very similar frequency responses). I'm getting the best results using just two of the subs though - one of the cool advantages to my room and our ear's inability to localize bass accurately is that I can put the right subwoofer 3 feet from the ground on a "shelf" to "balance out" the modal issues in my room. By having the mains as close as possible to the subs I also ensure that the sound arrives at nearly the same time from all 4 speakers (2 mains, 2 subs). One of these days I'll get around to putting two more subs towards the rear of the room - again equidistant from the listening position, but not perfectly symmetrical in the room. The goal will be to further distribute peaks from the resonances in the room - knowing full well that the resonances will never go away. The basic goal here would be to increase the SPL capability of the system.....just for showing off [] Eventually I'll get around to obtaining some DSP and manually implementing the crossover to the mains and then running a 3rd subwoofer (probably 2 subs wired in parallel) for the LFE. For an example of this, check out sfogg's system on the forum. Anyways....the ideal setup would be at least two subs with a third doing LFE duty. The 3rd sub in this configuration would never play until called upon during a movie...really a waste of money, but the ideal usually is [] Somewhere amidst all the madness (and it's already been mentioned) is that sometimes it's better to go with a single good sub instead of two lessor subs. That's where the wonderful world of price points and using your own ears comes into play. Sadly the feasability of accurate demonstrations are lacking, so you gotta rely on the experiences of crazy folk on the internet...Best thing you can do is take everything with a grain of salt, use your head, have fun, and remember it's all about compromise [] Btw, if you like building stuff....you might consider the option of building your own sub...but them's a whole nother can of worms. The nice thing about DIY is that you're guaranteed to enjoy the result - even if it sucks because you were the one building it [H] Quote Link to comment Share on other sites More sharing options...
sfogg Posted January 31, 2007 Share Posted January 31, 2007 Mike, Dr. David Griesinger has several papers about the need for stereo bass reproduction and how/why bass sounds so different in a hall as compared to a typical home setup. http://world.std.com/~griesngr/ Loads of other info there as well. Shawn Quote Link to comment Share on other sites More sharing options...
DrWho Posted January 31, 2007 Share Posted January 31, 2007 Thanks [] Quote Link to comment Share on other sites More sharing options...
PrestonTom Posted January 31, 2007 Share Posted January 31, 2007 Mike, Dr. David Griesinger has several papers about the need for stereo bass reproduction and how/why bass sounds so different in a hall as compared to a typical home setup. http://world.std.com/~griesngr/ Loads of other info there as well. Shawn Darn it ..., That was the reference I was trying to remember while I was driving to work this morning. I remembered someone had published on this very topic before. Alas, my memory is no longer a precision instrument. -Tom (if I remember correctly) Quote Link to comment Share on other sites More sharing options...
bodcaw boy Posted January 31, 2007 Share Posted January 31, 2007 Just a few quick comments... You cannot tame room modes by placement of subwoofers. The best you can try to do is to try to stimulate different modes and thus spread out the peaks minimizing their sums, but you cannot change the modal frequencies that are determined by the dimensions of the room and the acoustic energy pumped into the room. And if the room dimensions result in the close spacing of the modal center frequencies, you can reposition the subs and crawl around on your hands and knees all you want. You may find a lesser of all evils listening position, but you aren't going to effect the room modes at all! And phase is only important in terms of absolute phase - the total time the direct signal takes to arrive, so if the distance from each source is different, the phase cannot be aligned in a meaningful way. You use delay for this. As long as the subs each have a crossover with definable low pass and high pass crossover points, you can use them to reproduce adjacent passbands. I would suggest this approach, using each to reproduce an adjacent passband. If you simply want more gain, a larger sub would be ideal, but lacking that, stacked subs are best followed by 2 placed immediately adjacent to each other. I would personally still prefer the two reproducing adjacent passbands. And at this point, far too much energy is being spent debating this topic.[] If you want to play with room placement, read the HK whitepaper posted many times on the thread (you might search Doc's threads if I am not mistaken). But be aware that there are other issues not addressed by the paper. Have fun. i thought you said quick.....[|-)] have a blessed day, roy delgado Quote Link to comment Share on other sites More sharing options...
colterphoto1 Posted February 1, 2007 Share Posted February 1, 2007 Mike, Dr. David Griesinger has several papers about the need for stereo bass reproduction and how/why bass sounds so different in a hall as compared to a typical home setup. http://world.std.com/~griesngr/ Loads of other info there as well. Shawn Can we just use more full range speakers throughout out systems and/or lower the crossover point to the subs to achieve this same result? I recently added a rear sub to my dual THX front system and it's amazing haveing some rumble behind you. I think I'll keep it. Quote Link to comment Share on other sites More sharing options...
colterphoto1 Posted February 1, 2007 Share Posted February 1, 2007 "stacked subs are best"-- yeah baby wooohoo, that's what I've been doing with my THX's since day one (Thanks Trey and SteveP)! It's awesome. I do wonder why stacked is better than side-by-side, could it be timing and phase issues? Roy- am I getting any smarter at this stuff? some days it seems that the more I learn the less know, is this a common Klipsch phenomenon? Quote Link to comment Share on other sites More sharing options...
sfogg Posted February 1, 2007 Share Posted February 1, 2007 "Can we just use more full range speakers throughout out systems " Yes, bass response down to around 40hz is what is needed. Below around 40hz the perceptual difference between stereo and mono bass gets pretty much inaudible. Along with stereo bass response you of course need material with stereo bass in it, not everything has that. Or you need processing like Lexicon's 'bass enchance' which decorrelates the bass and applies processing to increase ITDs. Shawn Quote Link to comment Share on other sites More sharing options...
mas Posted February 1, 2007 Share Posted February 1, 2007 "stacked subs are best"-- yeah baby wooohoo, that's what I've been doing with my THX's since day one (Thanks Trey and SteveP)! It's awesome. I do wonder why stacked is better than side-by-side, could it be timing and phase issues? Roy- am I getting any smarter at this stuff? some days it seems that the more I learn the less know, is this a common Klipsch phenomenon? Vertical stacking is the optimal configuration - i just hazard to recommend it to many who may simply try to stack their SVS and Hsu (or whatever combo) they might have with, well, let's just say less than optimal - read 'disastrous' - consequences. There will still be some polar and comb filtering anomalies, and this configuration addresses two of the factors that effect the image - One, our vertical image perception stinks (that was the exact technical term used in the psycho-acoustical research if i remember correctly) and thus we do not notice the vertical separation as well as we do the horizontal, and the polar anomalies which would be narrower for horizontal arrays are wider when turned on their side. (...Thus, for a given frequency, you can move about the room without experiencing the vertically oriented nulls, assuming you are at the proper height!...that is until the room modes get you! Gee, there's no free lunch!) Well, realizing my words aren't nearly as illuminating as a picture, take a gander at the attachment and turn the diagram for horizontally spaced devices on its side to see the patterns for a vertical arrangement, Of course, the frequency response and comb filtering diagram will still make more sense left as it is...[] PolarPatterns&CombFilters&Balloon.s.pdf Quote Link to comment Share on other sites More sharing options...
mas Posted February 1, 2007 Share Posted February 1, 2007 Sorry, your edit wasn't big enough [] i thought you said quick.....[|-)] While elsewhere...'I'm confused' whereas others complain that they 'know it all'. Gee this forum is fun... [] It's all relative, isn't it?....[] Quote Link to comment Share on other sites More sharing options...
Roc Rinaldi Posted February 1, 2007 Author Share Posted February 1, 2007 Well.............I'm confused and I'm having fun. Getting back to the subject. I guess that the answer is "two subs could be better than one--it depends". Now Colter has me thinking a bit differently. Do I place the two subs side-by-side; or stacked (how do you do this if the larger sub is Dr. HSU's VTF-3 HO Turbo ?[ http://www.hsuresearch.com/products/vtf-3-ho-turbo.html ]); or do I place the smaller sub in the back of the room which might help out on movie special effects? How long can a sub line feed be before the signal gets weak? ....what's a poor boy to do? Please keep in mind that my main listening is stereo old rock music and only secondarily to movies. Quote Link to comment Share on other sites More sharing options...
DrWho Posted February 1, 2007 Share Posted February 1, 2007 At the frequencies being operated by a subwoofer - the difference in polar response from a vertical and horizontal arrangement isn't going to matter at all. Quote Link to comment Share on other sites More sharing options...
mas Posted February 1, 2007 Share Posted February 1, 2007 Just put them next to each other! See what I mean...[] Quote Link to comment Share on other sites More sharing options...
mas Posted February 1, 2007 Share Posted February 1, 2007 Here is another very good paper that deals with LF arrays. Note carefully that it assumes a large acoustical space and totally disregards room modes (a small acoustical space issue)! In the small spaces that comprise listening rooms, much of this is not an issue. Or to put it perhaps more accurately, other issues take precedence. But the acoustics principles are sound, sorry, make that 'valid'. Also, ArrayShow is no longer supported by EV since their unfortunate holding company restructuring, (about which, the less said the better.) So please don't call EV with regards to the program - besides, the number listed is not current...but feel free to call and make the day of whomever answers. If you have questions, PM me on site. I have been known to know a few things... LowFreqDirectivity.c1.pdf Quote Link to comment Share on other sites More sharing options...
Roc Rinaldi Posted February 1, 2007 Author Share Posted February 1, 2007 How much is the fathom f112 from JL Audio? I'm weakening. Quote Link to comment Share on other sites More sharing options...
Roc Rinaldi Posted February 1, 2007 Author Share Posted February 1, 2007 The JL Audio fathom f112 is $2600 - $2700. Wow. After reading several articles it looks like the recommended sub placement for two subs in mid-wall on opposite sides. So now maybe Dr. HSU on one mid-wall and my Velodyne on the opposite mid-wall. These two subs are not that similar so I'm not sure what problems I may introduce use two dissimilar subs, but it's worth a try. Oh God, maybe I should just get two f113s, sell the Velodyne and be done with it. I have a feeling that's where I'm going to wind up eventually. May God help my marriage. Quote Link to comment Share on other sites More sharing options...
DrWho Posted February 1, 2007 Share Posted February 1, 2007 Well you might want to consider the Danley DTS-20 before going the route of dual f113's... [] (I believe they retail for something like $4k???) http://www.danleysoundlabs.com/DANLEY_tappedpagehome.htm Quote Link to comment Share on other sites More sharing options...
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