I can localize my sub - any recomendations? - AVS Forum
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post #1 of 7 Old 01-08-2013, 06:58 AM - Thread Starter
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I just got an Energy Forcefield 3 sub to replace my PSB 5i after the amp died for the 3rd time. I chose the FF3 at the local dealer because I got trade in for the 5i and I like how it sounds. Here's the problem: I can localize its location when listening to music. I have moved it all over the room and was going crazy. I think I have finally figured out why I can locate it. Its my wood floors. This thing really can shake a room and for movies it is awesome. For music it blends well with the speakers. I don't notice the x-over point but because the floor shakes so nicely I can tell where the bass is coming from. I think the best solution is to get a 2nd sub but any suggestions until then ?

The speakers are crossed at 80hz.

Thanks,
Robert

PS. It will be possible but a pain to center the sub in front of the MLP.
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post #2 of 7 Old 01-08-2013, 07:11 AM
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If you can localize them the crossover is too high and/or you're pushing them too hard. You may have them crossed at 80Hz but most crossovers don't have sharp enough filters to remove all audible content for at least an octave above the crossover, and that means you're hearing locatable frequencies. High THD also raises the content of locatable frequencies, and playing a sub too loud increases THD.
Cures include lowering the crossover, using both the crossover in the receiver and the low-pass filter in the sub amp to increase the roll off rate, aiming the sub at the wall to acoustically filter out above bandwidth content, and adding a second sub so you don't have to run too high a level with just one.
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I think I have finally figured out why I can locate it. Its my wood floors.
That doesn't help, as wood floors reflect locatable frequencies. But they reflect all frequencies and should be covered with carpet anyway. They might look really nice but they sound really bad.

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post #3 of 7 Old 01-08-2013, 08:40 AM
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"aiming the sub at the wall to acoustically filter out above bandwidth content"

Bill, can you expound upon this statement a little bit? I have my dual opposing subs NOT currently firing into the corner of the wall and the other end in the room. I basically have both drivers facing the wall and notice a null in my listening position. Does it matter in this case which way the drivers are facing? Could they be causing the null or is it strictly the location of the sub? Thanks!
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post #4 of 7 Old 01-08-2013, 08:45 AM
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Originally Posted by walke108 View Post

I have my dual opposing subs NOT currently firing into the corner of the wall and the other end in the room. I basically have both drivers facing the wall and notice a null in my listening position. Does it matter in this case which way the drivers are facing? Could they be causing the null or is it strictly the location of the sub? Thanks!
With dual opposing you can't take advantage of the acoustic filtering that comes from down or rear firing, since one cone will always be aimed upward or outward. Nulls are always placement sourced.

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post #5 of 7 Old 01-08-2013, 09:05 AM
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Thanks Bill!
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post #6 of 7 Old 01-08-2013, 09:22 AM - Thread Starter
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I really mis-stated my theory. My floor is actually carpeted but it is a converted attic with wood sub-floor and joists. What I meant to say was the I can locate the sub because I FEEL it through the floor giving the directional info. I think the speakers and sub sound good and blend together well. I have tried pointing the speaker different directions and moving it in and out of corners. It is currently a couple feet off center on the near the left main but closer to center. If you aren't familiar with the sub it is front firing with a passive radiator on the bottom.

I will play with the x-over again but since the low frequencies do a lot of the floor shaking I don't know that it will help.

As far as level goes. I use Audessey XT on my Denon 3808 to set the levels. I like bass but I don't like to overdo it so I leave the level as it is set. I hope with the sub input at less than 50% and the AVR channel level at -5 I shouldn't be going past its capabilities.
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post #7 of 7 Old 01-08-2013, 11:21 AM
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Quote:
Originally Posted by rec head View Post

What I meant to say was the I can locate the sub because I FEEL it through the floor giving the directional info.
Nope. Snakes have the ability to directionally locate the source of vibrations transmitted through the ground, but we don't.

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