Subwoofer Placement - AVS Forum
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post #1 of 10 Old 04-16-2013, 05:49 PM - Thread Starter
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Greetings all
I've got a sub about 4 months ago but i've been wondering if my placement is optimal. I got the sub because i listen to a lot of rap so i'm not too worried about the bass being overpowering or something.
I notice that when I stand at the door (this is the picture thats lookin at the desk from the right) the bass feels like it's got a lot more body and it's much much louder. I'm not that knowledgable about speakers and stuff so I'm not sure if this is because of the distance givin it more time to reverberate or something? I know that low frequency sound is omnidirectional, but could the desk next to the sub be directing sound waves forward towards the door?
I used to have the sub on the left side of the desk but when i realized how much louder the bass was at the second desk I thought to move it to where it is right now, also the outlet is on that side so it's much easier to plug into my extension cord.

If you know what you're talking about you probably don't need me to explain this but the difference i notice when i'm by the door is bass seems to kind of linger a little bit longer? It feels fuller, i'm not quite sure how to explain what i mean







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post #2 of 10 Old 04-17-2013, 02:45 PM
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post #3 of 10 Old 05-06-2013, 06:25 PM - Thread Starter
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im familiar with the subwoofer crawl but my main question was whether or not the desk will interfere with the sub. Right now i have the sub on the left side and i've pulled my desk forward and it sounds better than when the desk is back. Only problem is when i listen to the sub on one side, it's hard to compare with the sound when it's on the other side as i kinda forget. whatever i'll get someone to come over and stand back n judge for me
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post #4 of 10 Old 05-07-2013, 06:17 AM
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Quote:
Originally Posted by beefjeep View Post

im familiar with the subwoofer crawl but my main question was whether or not the desk will interfere with the sub.
Only if its dimensions are a significant portion of one wavelength. One wavelength at 80Hz is 14 feet, at 30Hz 38 feet.
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post #5 of 10 Old 05-09-2013, 06:00 PM - Thread Starter
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Originally Posted by Bill Fitzmaurice View Post

Only if its dimensions are a significant portion of one wavelength. One wavelength at 80Hz is 14 feet, at 30Hz 38 feet.

well the surface is only about 2x4--is how close it is to the sub relevant?
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post #6 of 10 Old 05-09-2013, 07:40 PM
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Originally Posted by beefjeep View Post

well the surface is only about 2x4--is how close it is to the sub relevant?
Four feet is one wavelength at 280Hz. At that frequency and above it's a reflective barrier. A couple of octaves down from that at 70Hz it's acoustically invisible. Read why here in section 1-5, diffraction:
http://www.jblpro.com/pub/manuals/pssdm_1.pdf
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post #7 of 10 Old 05-14-2013, 11:03 AM - Thread Starter
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i just took the ap physics test yesterday i shouldn't be learning any more...

what you said makes sense but it's kinda early i'm having trouble followin the doc you sent (ill read it in depth later). but when I pull my desk away from the wall (leaving about 2 feet of empty space behind it / parallel to the sub) i'm pretty sure that the low frequencies sound better. Is this just because my speakers are farther from the wall so the higher frequencies dont sound as loud (i doubt it but still)?
I'm not really a pro on Even though the desk might not be directly interfering with the low frequency waves does having this empty space let the sub get some resonance or something?
thanks a lot Bill
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post #8 of 10 Old 05-15-2013, 11:04 AM
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SBIR, Speaker Boundary Interference Response

A number of things are at play here, however consider the complex manner at which the room's boundaries interact with the acoustic output of both your desk-top speakers, and the subwoofer.

This from studio monitor mfr Genelec will help.

This pages describes the interaction of a full range loudspeaker.

Here is an additional page quite helpful explaining related issues with a sub/sat system.




The RedSpadeAudio blog, from Paul Spencer, is always an informative read. Although it's somewhat redundant with the Genelec info above, he always offers solid advice and it's well worth your time exploring his various pages.


Hope all this helps

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post #9 of 10 Old 05-15-2013, 11:24 AM
 
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Who knew when buying subwoofers, one would have to become an acoustical engineer. tongue.gif
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post #10 of 10 Old 05-16-2013, 11:37 AM
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Quote:
Originally Posted by BeeMan458 View Post

Who knew when buying subwoofers, one would have to become an acoustical engineer. tongue.gif

smile.gif

Anyone can buy 'em, ... but ... upon determining the bass has better articulation standing over here, or the blend between the sub system and mains possesses great punch and tightness when placed like so, ... etc, etc.. then the enthusiast, or novice finds themselves here, at AVS.

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