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Discussion Starter · #1 ·
I have a relatively low-powered JL subwoofer. The acoustic "hole"(or whatever it's called) is on the rear. I have it placed in the corner of my room about 6 inches away from the rear wall and touching the right wall.


When I was watching a movie earlier, I got up to get a drink and as I walked out of the room, the bass was easily 2-3 times more powerful based on where I was standing. When I sit back down in front of my set, all of the power seems to die out of the sub. I'm assuming this is because of the acoustics of my room. How do I figure out where to place the sub to give me the best results for my seating arrangement?


By the way, this is a real cheapo set-up in my bedroom, but obviously I'm missing out on a lot of audio power here.
 

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The corner should be good, and is usually a recommended place. I had a similar problem placing my sub, takes a while, now it's under a table and sounding great. I believe the usualy guidelines are to keep it away from doors, and place them in corners. Another method is to place the sub where you are seated, then run around the room listening to where it sounds the bass sounds the best. Wherever, that spot it, place the sub at that location.


Also, by power, do you just mean boominess, does it blend in with the rest of the sound? Or is it just the one note boom you hear from car stereos? An old sub also sounded a lot more powerful a few feet away where I was standing, but afer listening to it a while, it was just one note bass.
 

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Looking at the attached image I would move the sub to the opposed side,next to the TV/cabinet.


Another simple way to find a proper spot for the sub is to place the sub where you sit,play some bass heavy music or use the free version of TrueRTA (if you have a laptop)to generate tones(30-80Hz) sending the signal to the sub.


Crawl around where you can place the sub,you should then place the sub in the spot that sounds best to you.
 

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Discussion Starter · #4 ·

Quote:
Originally Posted by Imp /forum/post/0


The corner should be good, and is usually a recommended place. I had a similar problem placing my sub, takes a while, now it's under a table and sounding great. I believe the usualy guidelines are to keep it away from doors, and place them in corners. Another method is to place the sub where you are seated, then run around the room listening to where it sounds the bass sounds the best. Wherever, that spot it, place the sub at that location.


Also, by power, do you just mean boominess, does it blend in with the rest of the sound? Or is it just the one note boom you hear from car stereos? An old sub also sounded a lot more powerful a few feet away where I was standing, but afer listening to it a while, it was just one note bass.

Yes, it's a decent sub. By power, I mean the "depth". I can feel it in my chest when I stand up. When I sit down, it sounds like I turned down the lower frequencies on my equalizer.
 

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Discussion Starter · #5 ·

Quote:
Originally Posted by TheEAR /forum/post/0


Looking at the attached image I would move the sub to the opposed side,next to the TV/cabinet.


Another simple way to find a proper spot for the sub is to place the sub where you sit,play some bass heavy music or use the free version of TrueRTA (if you have a laptop)to generate tones(30-80Hz) sending the signal to the sub.


Crawl around where you can place the sub,you should then place the sub in the spot that sounds best to you.

So that method actually works? And I assume I should elevate it to where my head would be? Also, which direction do you think I should aim the acoustic hole thing?


I heard of this method a long time ago, but it sounded kinda silly to me. Now that I think about it, it's simple science really.
 

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Quote:
Originally Posted by fugiot /forum/post/0


So that method actually works? And I assume I should elevate it to where my head would be? Also, which direction do you think I should aim the acoustic hole thing?


I heard of this method a long time ago, but it sounded kinda silly to me. Now that I think about it, it's simple science really.

Exactly,silly..yes thecrawling on the floor part.The crawling is for a good cause,and once you have the spot...stays there.



The way furniture is set in this room, you have to compromiose,but an acceptable compromise should still give you a good result.
 

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The "Crawl Test" certainly works. However, the bigger problem in your room is not where the sub is placed; it's where *you* are placed. You're almost in the exact center of the room. This is generally the spot in most rooms where the greatest cancellations occur. This is why the bass disappears in your listening position. Try moving back towards the back wall a few feet. Also try sitting directly against the back wall. Figure out the best listening postion first, place the sub at this position, and *then* do the "Crawl Test".


Good luck.


Craig
 

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Discussion Starter · #8 ·

Quote:
Originally Posted by craig john /forum/post/0


The "Crawl Test" certainly works. However, the bigger problem in your room is not where the sub is placed; it's where *you* are placed. You're almost in the exact center of the room. This is generally the spot in most rooms where the greatest cancellations occur. This is why the bass disappears in your listening position. Try moving back towards the back wall a few feet. Also try sitting directly against the back wall. Figure out the best listening postion first, place the sub at this position, and *then* do the "Crawl Test".


Good luck.


Craig

Wow, thanks! I would've never realized that, but it makes so much sense now. Problem is, I have a 26" HD set, so sitting across the room makes it hard to see any detail. Looks like I have some rearranging to do.
 

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Discussion Starter · #9 ·
Oh yeah, what direction should I point the "bass hole" in when I'm doing the crawl test? Towards the TV?
 

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Quote:
Originally Posted by craig john /forum/post/0


The "Crawl Test" certainly works. However, the bigger problem in your room is not where the sub is placed; it's where *you* are placed. You're almost in the exact center of the room. This is generally the spot in most rooms where the greatest cancellations occur. This is why the bass disappears in your listening position.

This sounds exactly like my room. In the middle of the room there's basically no bass at all. Along the walls the bass is good, and in the corner it's way too much. Luckily our sofa is along the wall.
 

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Quote:
Originally Posted by fugiot /forum/post/0


Oh yeah, what direction should I point the "bass hole" in when I'm doing the crawl test? Towards the TV?

For the "Crawl Test", you can basically point the "port" any direction you like. Once you find the best spot for bass, you can try turning the sub and see if the response changes much. If it doesn't, place the sub where you heard the best response. Then play around with minor positional and directional changes until you optimize the sound.


Craig
 

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Quote:
Originally Posted by redline65 /forum/post/0


This sounds exactly like my room. In the middle of the room there's basically no bass at all. Along the walls the bass is good, and in the corner it's way too much. Luckily our sofa is along the wall.

As a general rule, in most rooms, the best spot for bass response is at "odd" fractions of the room dimensions, i.e., thirds or fifths. IOW, if the room is 15' long, the best locations would be at 3 ft. or 5 ft. from the back wall.


Craig
 

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Craig J.,


My bad,true in the center of the room bass will be lesser. Best to sit 2/3 in the room if at all possible.
 

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yep...i've heard 3-5 feet from the back wall is the "place to be"
 

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Quote:
Originally Posted by fugiot /forum/post/0


as I walked out of the room, the bass was easily 2-3 times more powerful based on where I was standing ... How do I figure out where to place the sub to give me the best results for my seating arrangement?

Today seems to be "subwoofer placement day."
As you observed, corners is where bass builds up the most. I just posted this two minutes ago for someone else:


When I bought my Carver Sunfire a few years ago, I tried a variety of places. Then I looked in the manual
and it said to put it in one of the front corners. Bingo, that was clearly the best place. More recently I got an SVS PB12-Ultra/2 subwoofer and noticed that its manual also said a front corner is best. By then I didn't even need to experiment. I put it there and it's even more fabulous than the Sunfire.


That said, a front corner is clearly the loudest location, but it won't be the flattest unless you have a fair number of bass traps. Loud works for me
but I also have 40 traps in my living room home theater and they reduce the problems (peaks, ringing) you get with corner placement.


The only way to know for sure which place is best is to measure the response. But you need to measure to a high resolution such as 1 Hz intervals. This can be time consuming because moving the sub even an inch or two can make a real difference. So you end up measuring, moving, measuring, moving, and so forth for the better part of an evening.


One useful method is to put the subwoofer at the listening position on a chair, then play some bass-heavy music and crawl around on the floor listening for where the bass is the most even. Once you find the best place by ear, put the subwoofer there. One problem with this is the key of the music affects what you hear. If the music has tones that align with the room's modes, then this method can work pretty well. But if the music is in a key that doesn't excite the room modes, then other music that does excite the modes may sound unbalanced. One solution is to use pink noise instead of music. But again, the only way to know for sure where the low frequency response is flattest is to measure.


I hope this helps.


--Ethan
 

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Just for the records, I've been doing the crawling test on my HT room and found the best spot to be at rear wall, right besides the sofa.


My room is only 20 x10' wide (9' high).

On my previous arrangement, I used to have the SW placed alongside the left wall, but now is far, far better though.

BTW, I do enjoy bass, but I'm not a bass nut at all.


Just attaching an image for a better overview.


Cheers.
 

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Quote:
Originally Posted by Ethan Winer /forum/post/0


... That said, a front corner is clearly the loudest location, but it won't be the flattest unless you have a fair number of bass traps. Loud works for me but I also have 40 traps in my living room home theater and they reduce the problems (peaks, ringing) you get with corner placement.

Does that mean that bass traps will do more for a corner loaded sub vs. a sub in the middle of a wall?

Similarly, will a sub in the middle of a wall inherently have less peaks and ringing problems?
 

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Quote:
Originally Posted by gbondioli /forum/post/0


Does that mean that bass traps will do more for a corner loaded sub vs. a sub in the middle of a wall? Similarly, will a sub in the middle of a wall inherently have less peaks and ringing problems?

Those are both good questions.


Bass traps will help (are mandatory IMO) no matter where the sub is located. Bass traps are also needed in a room with just a 2-channel setup and no sub.


As for your second question, Yes and No.



The room modes will ring for as long as they'll ring, regardless of where the sub is placed. But the sub placement will affect the overall level of peaks as well as the ringing. So if you put a sub in the corner of an untreated room, it will excite the resonances quite a lot and they'll ring for, let's say, one second. Now, if you move the sub somewhere else and a particular mode is not excited as much, the volume level and the ringing will both be reduced. But the proportion of level versus ringing remains the same. In order to reduce the decay time of the ringing relative to the level requires adding absorption into the room.


--Ethan
 
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