Scott, I think that you misunderstood me. Banging on the walls will create a "boooom" sound all around the room (in the corners as well as the wall). That boom is wall resonance and will make your room vibrate at that frequency as the sub creates low frequencies making that ragged output as you called it. Check out my original response to see how to avoid that boomy ragged sound. Your article said that subs in the corner will produce a powerful bass. Now, with the wall treatment, you can avoid the ragged sound.
Another hint to avoid boom is to create a false corner made out of several layers of medium density fiberboard glued and screwed together as I have done. The false wall should sound like a rock when you hit it. This false wall will concentrate the bass and make it fast, but smooth. If you still have this THING about putting the sub on the side or front, just place the false corner behind it there. |
My experience with two Nestorovic type 8 passive subs was:
Flatest responce, best sound, was the two subs in the corners but 4-6" out from rear wall and FACING (firing towards) the rear wall. Mile Nestorovic has always said facing the rear wall gets the best sound but had recommended 2 feet from the corners. Each sub is slanted for time aligning I beleive and has 2 12" speakers. They cover from 200hz on down to about 20hz. Radio shack meter and Rives test cd were used for measurement. I did not try every concievable position but many. |
Warrenh and Stanhifi - Right-on! But the sub also added benefits, maybe most of the benefits, beyond simple LF response in my system. Mostly increased quality in the mid-range (sounds strange, I know) and a much better recreation of "acoustic space".
scott |
Redwoodgarden-
Thanks for sharing your experience. I agree that the corner is best for max SPL. But, I amicably disagree with one part, or perhaps simply misunderstand-
***Don't blame the corner for a one note, or boomy bass. Blame that on the resonance of your walls.***
Actually, I think it is the corner location. My wall "resonances" (does this refer to wall dimensions, construction, something else?) are uniform throughout the room. So that should not be a factor, again unless I misunderstand you.
I wish I had taken a response measurement when the sub was in the corner, to compare it with its present location, to have data for my room. But others have measured various placements. Check out the two links in the original posting. Maybe they will interest you as much as they did me. In both articles, corner location measurements show powerful but ragged output, compared to mid-wall. My personal experience was consistent with this. Both articles also used models and measurements to advocate multiple subs.
Food for thought.....
scott |
Seurat,
***In the end this issue can be challenging or frustrating. Adopt the challeging view. Try a scientific approach: do some reading, make your calculations, do the necessary changes, do some music test and then report here.***
Yes! There are many variables, many not easily adjusted (like room dimensions and wall construction) leading me to say in an earlier post that obtaining great bass at home requires both knowledge and effort, as well as a little good luck. I prefer the path of knowledge and effort, but as in all life, some good luck is welcome.
I picked up the Rives CD last week to begin with some primative response measurements (Rat Shack SPL meter). It's a start, for an objective benchmark. Will "report here".
Scott |
The boomy bass problem can exist because of: 1) Poor sub design; 2) room related problems (sound field and standing waves); 3) struture problems.
1)Most sub use large excursion cones, wich are more dificult to control, facing to speaker cone towards the floor loads the cone with an air load (increases the mechanical impedance of the load), wich will enhace the damping properties of the system (the cone will move in a more controled way). Facing the sub to the floor will extend the sub lower frequency range by use boundary reinforcement.
Sub design dont stop here, there are more parameters to account.
2)A uneven bass response can be a result of the sweet spot position in the sound field. Try change your sweet spot or the subs position.
Standing waves is a room geometric issue.If you excite some of the room modes, you will have uneven frequency response. You can deal with this problem by using tube traps or a judiciously use of furniture. Try using the sub with a lower level in order no to overexcite some of the room standing waves modes.
3)Struture-borne sound is created by the motion of the struture surface (wall). The sub excites the wall, the wall vibrates and excites the air. In this particular case putting the sub in the corner is a good option because of the increase of rigidity and damping created by the various wall intersections (do a nuckle test in the midwall and in the corner). This problem could be the most difficult to resolve, it could lead to wall work.
Redwoodgarden - "A good sub in the corner will allow a recording of a 64 foot organ pipe bring out a sensation of an external heart massage. Nice!" - Not in your room, because of room dimension limitations. The notes lower than the lowest room mode will only be perceived in a nearfield audition (close to the speakers).
In the end this issue can be challenging or frustrating. Adopt the challeging view. Try a scientific approach: do some reading, make your calculations, do the necessary changes, do some music test and then report here. |
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No Warrenh, I'm saying a sub IS needed and useful for any full range speaker system. Sorry I was not clear.
S |
Stan, I don't think so...If one has a pair of speakers that are beautiful and accurate top to bottom, adding a sub can still improve the sound even though the sub is not handling any deeper Hz the main can't. A recording, say, with the lowest Hz level being at around 35Hz, can be produced beautifully and accurately by a pair of speakers: you're saying a sub is not needed then? A sub, particulary a large one, (I'm assuming a quality sub, of course)will move more air than 6 or 10 inch woofer in the main speakers. Comparable subs (same manufacturer) will produce the same effects, as well. A 15" will move more air than a 10. Two more than one. Same Hz, but different feeling. There is more to a sub than simply reproduction of frequencies that the mains cannot handle. "Nothing more or less." warren :) |
Stanhifi: Not so fast with the negative response. If you paid attention to what I was saying, you would have realized I agreed that the subwoofer was there to reproduce every low frequency note accurately. The difference with having the subs in the corner is that it improves the efficiency and speed of the low frequencies and allows them to be at the same dB level as the higher frequencies. In short...flat across the spectrum. Don't blame the corner for a one note, or boomy bass. Blame that on the resonance of your walls. If you bang on your walls with a closed hand and it sounds boomy, then you have a wall resonance problem that needs to be corrected as mentioned in my previous response. The wall should sound like your banging on a brick wall. A good sub in the corner will allow a recording of a 64 foot organ pipe bring out a sensation of an external heart massage. Nice! |
I use a Velodyne HGS-15 crossed over at 80 Hz with a pair of KEF 104/2s, and have found that an Auralex SubDude eliminates boom and seems to extend low frequency response. The front of the sub is about 2' from both rear and side walls and towed in a bit toward the seating position.
Experienced listeners agree with me that integration with the main speakers is seamless, and that you cannot point to the source. I use the system about equally for listening to stereo music as well as movies and HDTV. I think it works well in both applications.
db |
Over a week since moving the sub out of the corner, I'm comfortable with the results. Sub-bass rolls forward naturally, supporting music with confidence and setting the stage for midrange and high-frequencies to sparkle. I'm not fully satisfied with the side location due to stereo effect. I will ultimately try the sub on the front wall, inbetween the mains. This should solve channel imbalances, while hopefully not losing the good qualities of the present side location. Unfortunately, this has to wait unitl after I replace the large rear projection TV (between my speakers) with a front projection system.
In conclusion, get 'yer subs out of corners for better performance! |
It is interesting that moving my ears (head) slightly forward or backward from my seat makes a noticable difference in bass. Room nodes are not visible, but they are very audible in my room. I also notice that the bass is much louder and boomy when I stand in a corner. Corners would be a terrible location for locating the equipment rack, even if convenient. |
I had that problem (boominess, one-notey bass, overhang, slow to start and slow to stop) in the past but ever since adding a subwoofer stand w/ some blue tak (or Office Depot substitute at substantial savings), most of the drawbacks are now gone. I think this is one of the most overlooked option but an absolute neccessity (at least for myself). I have been using and recommend this :
http://www.lovanusa.com/product_info.php?cPath=29_52&products_id=73
but other options should work well as long as they're well constructed and gives the sub some clearance to the surface beyond what cones can do.
Happy listening!
Luc |
>>But then a "smooth" sound is soft and quiet which defeats the purpose of a subwoofer.<<
Wrong. The purpose of a subwoofer is to reproduce lower frequencies that the mains are unable to handle accurately. Nothing more or less. |
The boomy bass that most audiophiles hear is due to resonance of the walls, not the corner position of the subwoofers. The corner position of the subwoofer intensifies the bass by acting as a megaphone which also can intensify the boomy resonance. This wall distortion can be neutralized with proper wall treatment (resonant sound channels, a double layer of half inch drywall: one gray, one green board, and with ACS sound absorbing squares sandwiched between the two boards). As mentioned by Ekovalsky, a digital sound processor will also work well.
All of my speakers (a pair of Klipschorns and a pair of TacT W410 subwoofers) are designed to fit into corners. With the Marchand XM6 crossover set at 35Hz, the two pairs of speakers are flat from 12Hz to 12000Hz. This is possible only with wall treatment and tweaking the metal horns in the Khorn.
It is true that placing the subwoofers in the center or sides of the room will make the bass "smooth". But then a "smooth" sound is soft and quiet which defeats the purpose of a subwoofer.
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Listen to Warren--do it by ear.
You're getting 6db+ of non linear bass reinforcement in corners.
Larry |
I have never had good experience with subs in the corner. I like mine right next (inches) from my mains. Makes seamless integration much easier to attain. I was very happy with one 10" sub in my last place, but looking back (I had the room for 2) two 12 inchers would have been better. Certainly, at loud volumes, with heavy bass lines, larger subs can crank and be very impressive, but they do just as well, at very low volumes, enriching bass Hz that the little guys have trouble with. In fact, that is what I appreciate the most. IMHO... warren :)
BTW, after oodles of tinkering, listening, back and forth from listening chair to subs, I found 50 Hz and 12 o'clock on the gain to be just right for my tympanics/room.-I adjusted the crossover by ear alone. When my rig sounded right? Whatever that Hz be it be. 50 in this case. The listening room dictates the crossover. Spoke to Jeff, the owner creator of James Loudspeakers. He does his subs the same way and recommends that to all two channel audiophools. |
I've lived with the Seismic Sub against the sidewall for a week or so. This location continues to work for me, the benefits outweigh the single drawback of lowered output. Bass quality is pretty nice now.
So, do I spring for a second huge subwoofer for the opposite wall? This hobby is getting ouit of control! |
Even better I placed my two subwoofer cabinets on their sides in front of the center channel speaker.There are no suppoorting walls, just the floor.The output dropped about6-8db but it was quite smooth.Corners stink. |
Put your pair of subwoofers in the corners and add a DSP correction/crossover device, like the TacT RCS 2.2X or DEQX PDC-2.6. Result -- maximum SPL, optimal transient response, no room resonances resulting in "bass boom", perfect time/phase and amplitude integration with the mains, and a steep crossover keeping the upper bass and lower midrange in the main channels where they belong.
With such a DSP device the corners are the best place for the subs. Conversely without such equipment the corners are probably going to be the worst location. |
Dear Cmpromo: I think that the problem that you have with that single Rel subwoofer is that you were using like a bass reinforcement not like an integrated part of your speaker system and that you only use one unit instead of two.
Please read this subwoofer links, I think that can help us to understand the whole subwoofer concept and its heavy advantages:
http://forum.audiogon.com/cgi-bin/fr.pl?eanlg&1117893153&openflup&27&4#27
http://forum.audiogon.com/cgi-bin/fr.pl?eanlg&1117893153&openflup&31&4#31
Btw, Sgr: you can try with your Revel subs what is on those links. It could be interesting what you could have about.
Regards and enjoy the music.
Raul. |
Dear Scott: In my case I agree with you about subs on the corner.
But this subject depends on each room and other issues like: sub design ( reflex, sealed, etc ), crossover points, volume/gain, etc..
The integration of subs to any room is a long test of trial and error but is wortwhile to take that time to do it.
Regards and enjoy the music.
Raul. |
When I added a second sub (temporarily on loan from my neighbor) to the system, it was positioned in the right front corner, symetrically opposite my sub. This configuration was much smoother than the single sub, but still not good enough. Re-positioning my single sub to the sidewall midpoint is better yet. Still, there is room for improvement, and I'll borrow my neighbor's sub again to check out the pair against opposite sidewalls.
On the issue of needing multiple subs because of left channel / right channel information, I confirmed this is required. Using test tones and disabling the mains, the subwoofer is clearly audible up to 200 Hz! And this is with a 24dB/octave crossover, with crossover frequency around 60Hz. A natural way to side-step the stereo signals is centrally locating a single sub between the mains, with summed left and right channels. When Bruce Edgar demos his horns, he uses a single Seismic Sub on the front wall, foregoing the second sub. I can relate to this due to the size of the enclosure (refrigerator-sized).
I am finally getting a glimpse of "quality" bass, after moving the sub out of the corner. This is a goal worth pursuing. To me, great bass is not about SLAM or other audiofool stuff. Great bass provides a robust foundation which supports the music, provides ambient and spatial information about the size / dimensions of the venue, and believe it or not, manifests itself most clearly in a better midrange experience. Unfortunately, great bass is really hard to obtain without effort, knowledge, and probably some element of luck.
scott |
for two channel sound I keep my subs as close to the mains as possible. Yes, two is better than one; and bigger is uaully better. Listen to two 10" subs in a system play the second cut Use Me on her Champion cd. Keep that in your typanic memory box until you get to hear the piece with two 15 inchers. You tell me which does it for you. This is particulary satisfying when you have oodles of air to move. warren |
In the last few months I have abandoned placing subwoofers in any corner. Currently, my subwoofer is actually placed BEHIND my listening chair and crossed over as low as it will go. I guess that since low frequencies are non-directional, the bottom still seems to be coming from the mains even though the sub isn't even in front of me. If you can, try it back there. |
How about some room treatments to help out? Like ASC tube traps in the front corners of the room as a bare minimum step to smooth out the standing wave etc. IMHO gear alone is not the answer. Just a thought, Check out the web site below. This may be old news to you but maybe not. Enjoy!
http://www.asc-hifi.com/acoustic_basics.htm |
I agree. Corner loading of subs for music sounds awful. Multiple subs sound much better than one! I use Revel Sub 30s. |
Cmpromo - My sub is an Edgar Seismic Sub, 18" JBL pro driver horn-loaded exhuasting on three sides. Your problems with the REL are similar, but bigger, than mine.
Programmergeek - yes, I agree with you. The uneven bass in my room was driving me crazy. I don't know how anyone can get smooth and musical low bass using a single sub in the corner.
There is alot of misinformation on this issue, and I hope this helps shorten the learning curve for someone else.
scott |
What kind of sub were you using. Which direction did the woofer fire? I experimented once with a Rel sub with my Dunlavy 4a's. It had a downward firing 10" woofer. I placed it in the right corner behind the speakers and it was amazing how it blended in. The sub sounded like it was just part of the speakers. The problem was, if the bass was weak in the recording it filled in very nice, but if the bass was already great the sub was just way too much. It seemed like I was adjusting the subwoofer level for every song and quickly returned it. Keep in mind, my speakers had great bass to begin with and I was just looking to fill in. It may have worked well with speakers less capable of low frequency response. |
Bass is had to control but you are right corner placement of a sub is usually recommended for HT that is what you are thinking of because it amplifies the sub and makes the sub sound consistent throughout the room. For audio or some HT I prefer a sub more in the middle. You need a much more powerful sub for this but the bass is more exact because it is not being amplified by the corner. Infact as you move the sub out from the wall you will get less and less bass and more accurately. Same with speakers... |
