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  Topic Review (Newest First)
04-22-19 05:14 PM
blekenbleu
Re: How to "bass crawl" to place dual subs?

My guess is that your original second proposal would be most expedient:
* Place one subwoofer in the primary listening position, playing pink noise
* crawl for "best" bass (either by ear or ideally real-time spectral display of calibrated mic)
* place and play subwoofer pink noise at "best" bass position, along with subwoofer at listening position.
* crawl for optimal second bass position with both subs playing,
accounting for constructive and destructive interferences.
03-23-19 01:44 PM
needspeed52
Re: How to "bass crawl" to place dual subs?

Quote:
perceval wrote: View Post
Best way is to use the REW software.

You can have REW play a pink noise, install the mic at your listening position and use the RTA settings mentioned in the post.

Then you can view in real time the changes happening when you move either of the subs.

PS. if you get cancellations that seem almost impossible to fix, try flipping the phase on one of the subs.

Follow directions from here:

https://www.hometheatershack.com/for...ml#post1612934
Correct me if I'm wrong, would it not be easier and just as accurate to place sub(s) at MLP and move mic around the room with the RTA settings and observe the response for best location(s)?
03-19-19 08:34 PM
theJman
Re: How to "bass crawl" to place dual subs?

Quote:
Philnick wrote: View Post
Thanks! It'll be a few months until I get the room rebuilt, but you've given me a lot to chew on.

BTW, I'm wiring the in-wall line-level runs from the AVR to the wall jacks for the subs using coax, with coax-to-RCA adapters at either end, and RCA cables terminated with whatever connector is needed at the AVR and each sub.

I'm assuming that coax will make decent in-wall line-level cables for the sub signals.
Coax typically has good shielding so that should work fine. Even so, I would try to keep the coax runs away from the electric cabling.
03-19-19 08:28 PM
theJman
Re: How to "bass crawl" to place dual subs?

Quote:
Philnick wrote: View Post
It just occurred to me that playing the downward-firing - and thus omnidirectional - sub in the main listening position would allow me to crawl for the loudest bass in both locations (in the front left and rear right parts of the room), rather than dragging each sub there plugged into a different jack.

Once I decide on the two locations, then I'd wire up a sub in each location.

Does this make sense?
I'm not quite sure I understand what you're saying but there is one point to clarify; bass is omnidirectional, irrespective of driver orientation. Front firing, down firing, side firing, it all pretty much does the same thing. There are some advantages/disadvantages to each alignment, but bass waves will propagate in all directions from every one of them.
03-18-19 06:50 AM
basscleaner
Re: How to "bass crawl" to place dual subs?

Possibly, we didn't understand to each other. When I told you about dimensions I meant, that for subs optimal position problem the main is to have correct room dimensions. These called the Acoustical dimensions, because they define bass behavior for small room and, as a result, the thimbre room quality. If you want to know, is there any corresponding to this term, you could send me room dimensions and I'll test by A.Lim code use for it.
03-17-19 05:58 PM
Philnick
Re: How to "bass crawl" to place dual subs?

It just occurred to me that playing the downward-firing - and thus omnidirectional - sub in the main listening position would allow me to crawl for the loudest bass in both locations (in the front left and rear right parts of the room), rather than dragging each sub there plugged into a different jack.

Once I decide on the two locations, then I'd wire up a sub in each location.

Does this make sense?
03-15-19 07:32 AM
basscleaner
Re: How to "bass crawl" to place dual subs?

Could you send your height, because your room dimensions may not be acoustical?
If "yes", that means you have troubles with bass sound quality, caused room, and you need to find the better dimensions.
03-13-19 09:10 PM
perceval
Re: How to "bass crawl" to place dual subs?

Best way is to use the REW software.

You can have REW play a pink noise, install the mic at your listening position and use the RTA settings mentioned in the post.

Then you can view in real time the changes happening when you move either of the subs.

PS. if you get cancellations that seem almost impossible to fix, try flipping the phase on one of the subs.

Follow directions from here:

https://www.hometheatershack.com/for...ml#post1612934
03-11-19 12:03 PM
Philnick
Re: How to "bass crawl" to place dual subs?

Thanks! It'll be a few months until I get the room rebuilt, but you've given me a lot to chew on.

BTW, I'm wiring the in-wall line-level runs from the AVR to the wall jacks for the subs using coax, with coax-to-RCA adapters at either end, and RCA cables terminated with whatever connector is needed at the AVR and each sub.

I'm assuming that coax will make decent in-wall line-level cables for the sub signals.
03-10-19 01:07 PM
theJman
Re: How to "bass crawl" to place dual subs?

Quote:
Philnick wrote: View Post
Should I slide the couch over a few feet in order to put the sub being tested on the floor? Putting the sub - particularly a downward-firing one - on the seat of a couch doesn't sound like it would work very well.
You could do that, or just lay it on the couch with the driver pointing out. Since bass is omnidirectional the room modes should be the same regardless of driver orientation.


Quote:
Philnick wrote: View Post
I have a hand-held Radio Shack sound level meter (the one with analog VU meters) that I can use for level-matching.

What can I use as a sound source for level-matching and for doing the bass crawl in the first place? Should I just use the place in my receiver's auto room correction, after running the test, that lets you travel a test tone manually from speaker to speaker, or is there something I could download and play?
That test tone generator sounds like it would be fine. You basically want a standard signal that you can use on both subs to set the level equally.
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