Big Null with 2 Subs - AVS Forum | Home Theater Discussions And Reviews
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post #1 of 7 Old 08-21-2019, 10:21 AM - Thread Starter
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Big Null with 2 Subs

Hoping you guys with a lot more knowledge than I have can lend a hand here. I have a large open room and my front speakers are GoldenEar Triton Ones. I've been running the LFE through their powered subwoofers and have the system setup as 2 subs. Running REW, I measured a pretty big dip for either speaker/sub individually, but when running both together there is a massive null at 40hz.

Is there anything I can do aside from just running the LFE through only one of them?
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post #2 of 7 Old 08-22-2019, 05:44 AM
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You need to change placement of at least one of the subs. You can do a sub crawl or measure with one sub in a different place in your room.


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post #3 of 7 Old 08-22-2019, 08:23 AM
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Quote:
Originally Posted by viorel View Post
You need to change placement of at least one of the subs. You can do a sub crawl or measure with one sub in a different place in your room.


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His "subs" are built into his speakers. They can only be moved by moving the speakers. Doing a sub-crawl will only be useful if he can place a speaker where the bass modules in the speakers work best.

spearfish25, you've encountered the problem with using "full-range" speakers... you need to place them where they need to be placed for imaging and soundstage... which is virtually NEVER the same place subwoofers need to go for bass response. This is why it's far preferable to use separate subwoofers that can be placed optimally for bass response.

Your *best* solution is to get separate subwoofers and then optimize their placements. That is a whole different discussion and is beyond the topic of this thread. However, if you go that route, visit the Subwoofer Forum for help with that.

Your second best option is to try adjusting the placements of your speakers. You're probably dealing with the length mode of your room, so try adjusting them along that axis. Move them closer to the wall behind them, or move them further out into the room, and see if you can impact the nulls caused by that mode. Just realize that everything you do to the speakers affects the response over the entire bandwidth f the speakers, so be sure you're not creating more problems than your solving by moving the speakers.

Good luck.

Craig
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post #4 of 7 Old 08-22-2019, 08:45 AM
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Alternatively, can you change your listening position and see if that doesn't help alleviate the null?
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post #5 of 7 Old 08-22-2019, 08:55 AM
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Quote:
Originally Posted by craig john View Post
His "subs" are built into his speakers. They can only be moved by moving the speakers. Doing a sub-crawl will only be useful if he can place a speaker where the bass modules in the speakers work best.

spearfish25, you've encountered the problem with using "full-range" speakers... you need to place them where they need to be placed for imaging and soundstage... which is virtually NEVER the same place subwoofers need to go for bass response. This is why it's far preferable to use separate subwoofers that can be placed optimally for bass response.

Your *best* solution is to get separate subwoofers and then optimize their placements. That is a whole different discussion and is beyond the topic of this thread. However, if you go that route, visit the Subwoofer Forum for help with that.

Your second best option is to try adjusting the placements of your speakers. You're probably dealing with the length mode of your room, so try adjusting them along that axis. Move them closer to the wall behind them, or move them further out into the room, and see if you can impact the nulls caused by that mode. Just realize that everything you do to the speakers affects the response over the entire bandwidth f the speakers, so be sure you're not creating more problems than your solving by moving the speakers.

Good luck.

Craig

+1 to Craig John, very excellent advice, indeed.

One thing I'd like to add is the way of measurement. Just like any room correction software, usually one measurement in space is not enough, our ears work differently (very much differently) than a microphone in space at one single position.

Best would be to take 6-8 measurements with mic at different places around the seating area and averaging them in REW. That will show a much more realistic picture of what is going on in the room acoustically vs. human ears.
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post #6 of 7 Old 08-22-2019, 11:44 AM
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@spearfish25
Despite the "excellent" suggestion to start spending your money before knowing the facts, I'd suggest to have a look at REW's room simulator first.

If the sim gives you similar results - especially the null - then you can use it to experiment how to minimize the problem in the sim - and afterwards try things in real. You can also add dedicated subs and try all kinds of combinations in the sim.
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post #7 of 7 Old 08-22-2019, 12:06 PM
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Quote:
Originally Posted by Skinfax1 View Post
@spearfish25
Despite the "excellent" suggestion to start spending your money before knowing the facts, I'd suggest to have a look at REW's room simulator first.
If the sim gives you similar results - especially the null - then you can use it to experiment how to minimize the problem in the sim - and afterwards try things in real. You can also add dedicated subs and try all kinds of combinations in the sim.[/QUOTE]
Yup, there's another "excellent" suggestion.
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