Roc Rinaldi Posted January 26, 2007 Share Posted January 26, 2007 I have a Velodyne 12" front firing sub. I am pretty sure I want to get a Dr. HSU 12" sub side firing. Rather than retire the Velodyne I was thinking of using both. Dr. HSU recommends putting them side-by-side. Is this better than locating them in different parts of the room? Quote Link to comment Share on other sites More sharing options...
darkside Posted January 28, 2007 Share Posted January 28, 2007 For one thing, I don't understand why people say Dr. HSU, but that's besides the point. First of all, because they are different subs, you are going to have different timbres of the speakers. Unless you're really picky, this would be a moot point, but its all up to the listener. Also, putting the subs side by side would create a single point source for the subwoofage whereas placing them on opposite sides of the room, say next to each main you use, would give you stereo subwoofage. But in really its all up to you. However, in general, I would say yes, two subs are better that one Quote Link to comment Share on other sites More sharing options...
Raider Posted January 28, 2007 Share Posted January 28, 2007 Mixing speakers is sort of like mixing wine. The two flavors might conflict with each other, they might blend well, or they might be great. No way to find out except to try it. Quote Link to comment Share on other sites More sharing options...
soundbound Posted January 28, 2007 Share Posted January 28, 2007 I've found that for me two is better. My two subs are diiferent and work fine together. I have mine on different sides of the room which seem to fill the room better. Makes the sub bass less directional. Experiment with them and enjoy the adventure. Quote Link to comment Share on other sites More sharing options...
mas Posted January 28, 2007 Share Posted January 28, 2007 I find it rather surprising that so many provide suggestions without any idea of your intended use... Do you intend for them to reproduce separate passbands? eg one from say 20-40 Hz, and the other 40-80Hz? Or do you want them to reproduce the same passband? I would recommend the first option. And without additional details and data, I would place then in a close packed configuration. If not, still more issues come into play ranging from coupling if the units are within 1/4 wavelength of each other to room gain to room modes and the room geometry which will contribute to many more factors to consider... Quote Link to comment Share on other sites More sharing options...
Roc Rinaldi Posted January 28, 2007 Author Share Posted January 28, 2007 I really appreciate the input. I don't know anything about this so the various comments are helpful. It's just that I already have a sub but, of course, I want more low sound. So I am considering Dr. HSU. (...we refer to him as Dr. HSU because he has a doctorate from MIT and his last name is HSU [ pronounced shoe ] and it's more fun than referring to HSU Research, the company. Back to my original question. ...No definitive answer seems apparent from the comments. I guess this is another of those "buy the new sub and listen to it as a replacement by itself. Then add the old sub back into the mix located side-by-side and listen again. My room is quite full so I don't have the option of placing the old sub anywhere but side by side, unfortunately. Quote Link to comment Share on other sites More sharing options...
darkside Posted January 28, 2007 Share Posted January 28, 2007 Garage sale??? Maybe??? I am almost certain you will get better imaging from the low bass section if they are spread apart. So maybe some room might be made. I don't know. The reason you've got no definitive answer is because we don't know what sounds good to you, only you know what sounds good to your ears so all we can do is make suggestions... Quote Link to comment Share on other sites More sharing options...
jt1stcav Posted January 28, 2007 Share Posted January 28, 2007 I would say you'd probably be better off buying a bigger, more powerful single sub than the Velodyne you have now. Since space is at a premium in your room anyway and mismatching different brands may not be the best fix sonically, a larger, more powerful active subwoofer would most likely increase overall output IMO. Sell your present sub and use that money to help finance a larger sub with more wattage. Just a thought... Quote Link to comment Share on other sites More sharing options...
darkside Posted January 28, 2007 Share Posted January 28, 2007 That is also a good option, in which case you should look into an HSU HO of some sort, maybe even a turbo version in you have the dough Quote Link to comment Share on other sites More sharing options...
mas Posted January 28, 2007 Share Posted January 28, 2007 Imaging!??? Short of going with one larger single sub, there is QUITE a difference in approaches offered! Reproducing the same passband with both in a spaced configuration will result in polar anomalies and comb filtering, even at these frequencies. Take a look at the modeled polars of 2 identical 18 inch subs placed 9 feet apart. Two different subs will be even more interesting. And the LF room modes have not yet been considered either, rendering the overall response even still more interesting. Opinions are fun, facts are even funner...[] Will the fun never end... 2 18inSubWoofers9ftSpacing.s.pdf Quote Link to comment Share on other sites More sharing options...
CECAA850 Posted January 28, 2007 Share Posted January 28, 2007 Ideally when someone uses 2 subs in the same room, they are the same model. There are of course exceptions. HSU makes a mid bass module so that you can use one sub for the low stuff and one for the slightly higher bass frequencies. If you use 2 simalar subs in close proximity to each other, you can virtually double the output of the single sub. If you spread them in different parts of the room, you can tame room nulls. Non colocated subs are harder to calibrate however as far as phase and gain are concerned. It's even possible to add a second sub to a system and get less output at the seated position! An SPL meter and test tones are a must for setting up ANY sub. Quote Link to comment Share on other sites More sharing options...
Zen Traveler Posted January 28, 2007 Share Posted January 28, 2007 In my personal situation I can state two subs are definitely better than one. My RSW-15 has been in the shop for a while now and I can't tell you how much I miss it. [] Quote Link to comment Share on other sites More sharing options...
mas Posted January 28, 2007 Share Posted January 28, 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. Quote Link to comment Share on other sites More sharing options...
Roc Rinaldi Posted January 29, 2007 Author Share Posted January 29, 2007 Wow. You guys are pretty good. This is sort of spinning out of control. All of the comments are good food for thought. Thank you so much. The Dr. HSU that I am considering is the big one. (Why not. I'm only getting older) So I will be getting a sub that is considerably larger than the one I already have. (130wpc vs. 500 wpc) Here is the one http://www.hsuresearch.com/products/vtf-3-ho-turbo.html If I get it (it's about $1100) I will first hook it up by itself in my best corner. Then listen a while. Then I can start playing around by adding the Velodyne next to the Dr. and listen. Maybe I could squeeze the Velodyne into another spot away from the Dr. and listen. You know how it goes. I just wanted to check and see if there was a consensus on dissimilar subs, as to sitting them side-by-side vs. spreading them around. I don't know very much about sound wave action and synergy relative to this. The comments have been very helpful. Any other thoughts, please add. Quote Link to comment Share on other sites More sharing options...
Hemihorn Posted January 29, 2007 Share Posted January 29, 2007 Read this Multiple subwoofers are easier to place http://www.sonicdesign.se/subplace.html By using two subwoofers instead of one, and placing them in opposite corners on the same distance from the listener, (it is best done in each corner behind the main speakers) there will be an obvious reduction of the room resonances, while the directly radiated sound pressure will increase. This is because two corners in a room will have opposite phase effects of the fundamental (half wavelength) room resonances acting in this direction. If we have two subwoofers placed on the floor against the front wall the horizontal standing wave will disappear. If we have two subwoofers in the same horizontal direction instead, but one placed on the floor and one up against the ceiling, the vertical standing wave will disappear. If we have four subwoofers (down left, up left, down right, up right) then we avoid both the horizontal and the vertical standing waves in those two directions (I then assume mono connected subwoofers). If you want to lessen the action of even higher order multiple standing waves, i.e. full wave resonance, 1.5 wave resonance and others, even more subwoofers may be added to the system. One example of an excellent placement of four subwoofers is an even distribution horizontally behind the main speakers. Quote Link to comment Share on other sites More sharing options...
TheEAR Posted January 29, 2007 Share Posted January 29, 2007 Room modes,pah. Just use enough subs to have a massive displacement to pressurise the room,modes...you will not be affected. Trust me it works. Just know you will need four to eight very capable subs(from 5-10L of displacement per sub) to achieve this in a very small room(under 1000cu ft). Modes modes modes,not a la mode to me. [] 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 hemihorn and ear for your input. The article on sub-woofer placements is helpful to me. I have about 4,000 cu. ft. in my room (22 x 24 x 7.6). I only have room for the two subs. I guess I'll have to experiment when the second one arrives. My current decision is whether or not to buy the second sub. It generally sounds like it would be a good move. Either I'll just use the new sub (the Dr.) or use both of them. I'll have to try side-by-side and then separately located to determine which sounds best. I'm stopping at 2 subs. I have a life outside of my musical interests. What I want to know is "Are there any subs out there that can blow out a candle placed 6" in front of the woofer?" This capability would be quite impressive to show to friends. Quote Link to comment Share on other sites More sharing options...
mas Posted January 31, 2007 Share Posted January 31, 2007 http://www.harman.com/wp/pdf/multsubs.pdfmultsubs.pdf Quote Link to comment Share on other sites More sharing options...
mas Posted January 31, 2007 Share Posted January 31, 2007 Side by side (Close packed within 1/4 wavelength)) simply acts to couple them so as to act as one larger unit. Additionally, subs in opposite corners (and I would love to see your second sub suspended from the ceiling) do not cancel out room modes as the rooms are not simple first order systems. I only wish such were the case encountered in real measured rooms. BTW, if superposition were so simple, you could extrapolate this to also mean that all such reproduced LF sound would be effectively canceled and eliminated from the space. And that would be a much more dramatic demonstration than your candle example. You might want to invite your friends over and also enjoy a Star Trek fest to accompany the (anti-climactic) dramatic sound canceling demo![] Quote Link to comment Share on other sites More sharing options...
Roc Rinaldi Posted January 31, 2007 Author Share Posted January 31, 2007 Suspended from the ceiling???.............................are you crazy? My wife would kill me before I got the chains hung. Does your answer indicate that there are subs out there that could and would blow out a candle? l like side-by-side closely packed acting like one larger unit. I think this translates to "more bass" doesn't it? Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.