Sub "Bottoming Out"? What Does That Sound Like ?
11-13-00, 01:31 PM
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Like this:
brrrrrrrrmmmmmmmm - no wait, like this - baaahhhrrruuuummmmm - no, hold on, let me try again - bbaahhrruummmm...
Seriously, the reviewer was saying the sub couldn't handle the lowest of the low frequencies. This can manifest as distortion (i.e., noise), or as a gaping hole in a frequency sweep (i.e., silence). I'd think such a problem would be apparent to you if you heard it.
brrrrrrrrmmmmmmmm - no wait, like this - baaahhhrrruuuummmmm - no, hold on, let me try again - bbaahhrruummmm...
Seriously, the reviewer was saying the sub couldn't handle the lowest of the low frequencies. This can manifest as distortion (i.e., noise), or as a gaping hole in a frequency sweep (i.e., silence). I'd think such a problem would be apparent to you if you heard it.
11-13-00, 09:32 PM
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Was it me?
When my REL Strata "bottomed out", it sounded like a "pop", as if it was an electrical static amplified. I am sure it was some part of the magnet structure hit something else. When I replayed the scene, and touched the driver, I felt some serious cone excursion during these "pops".
I still have to look into why this happened, because I calibrate my system to 75db, using two subs. Therefore, each sub by itself might not hit 75db. Most likely, the sub is not big enough.
When my REL Strata "bottomed out", it sounded like a "pop", as if it was an electrical static amplified. I am sure it was some part of the magnet structure hit something else. When I replayed the scene, and touched the driver, I felt some serious cone excursion during these "pops".
I still have to look into why this happened, because I calibrate my system to 75db, using two subs. Therefore, each sub by itself might not hit 75db. Most likely, the sub is not big enough.
11-14-00, 12:06 AM
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It will sound like a really bad popping or other distortion.
Severe bottoming will have a popping noise. Less severe will only be a distorted sound.
Regardless, both are destructive.
Lush Have you tried moving your subs around in the room or switching the phase switches? With two subs it is entirely possible that you're having phase cancellation problems in your room. Before you go out and buy new equipment, rule that out as a source of the inadequate bass response.
With phase cancellation, both speakers are working properly, but you don't really hear the output of both of them (hence the term cancellation)
HTH
[This message has been edited by edclem (edited November 13, 2000).]
Severe bottoming will have a popping noise. Less severe will only be a distorted sound.
Regardless, both are destructive.
Lush Have you tried moving your subs around in the room or switching the phase switches? With two subs it is entirely possible that you're having phase cancellation problems in your room. Before you go out and buy new equipment, rule that out as a source of the inadequate bass response.
With phase cancellation, both speakers are working properly, but you don't really hear the output of both of them (hence the term cancellation)
HTH
[This message has been edited by edclem (edited November 13, 2000).]
11-15-00, 04:40 AM
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edclem:
I'm sorry for being misleading in my post. What I wanted to say was this...
Each sub by itself is not set reach 75db relative to the other 5 channels when calibration is done at the same master volume. With 2 subs playing together, all channels reach 75db during calibration. I hope you didn't think my max spl from my subs was 75db when watching movies! Now that wouldn't be HT, would it?!
I recently moved, so it has forced me to play around with the sub positioning. I started with one sub, moving it around until I got the flattest response I could get with AVIA LFE sweep tones and my radio shack SPL meter.
I also chose a position that wouldn't overload one end of the sofa while sucking out the bass at the other end. Then I added the second sub, testing it's freq response WITHOUT the first one playing. Finally, I play them simultaneously, and checking the freq response. I am fairly certain that there isn't any significant cancellations, because it would have caught my attention. In fact, I was quite happy with the "flatness" that I achieved. I mean, not ruler-flat (that's impossible without $$$ measuring devices), but it is such that I don't get wicked peaks that drowns out everything else, or suck-outs so quiet that I don't hear it.
Cancellation with multiple subs is very real and is something all users should attempt to avoid. Even though I think I've got it right, you've made me think about my setup again. When I have time, I will confirm my sub positioning once more. Cheers.
[This message has been edited by Lush (edited November 15, 2000).]
I'm sorry for being misleading in my post. What I wanted to say was this...
Each sub by itself is not set reach 75db relative to the other 5 channels when calibration is done at the same master volume. With 2 subs playing together, all channels reach 75db during calibration. I hope you didn't think my max spl from my subs was 75db when watching movies! Now that wouldn't be HT, would it?!
I recently moved, so it has forced me to play around with the sub positioning. I started with one sub, moving it around until I got the flattest response I could get with AVIA LFE sweep tones and my radio shack SPL meter.
I also chose a position that wouldn't overload one end of the sofa while sucking out the bass at the other end. Then I added the second sub, testing it's freq response WITHOUT the first one playing. Finally, I play them simultaneously, and checking the freq response. I am fairly certain that there isn't any significant cancellations, because it would have caught my attention. In fact, I was quite happy with the "flatness" that I achieved. I mean, not ruler-flat (that's impossible without $$$ measuring devices), but it is such that I don't get wicked peaks that drowns out everything else, or suck-outs so quiet that I don't hear it.
Cancellation with multiple subs is very real and is something all users should attempt to avoid. Even though I think I've got it right, you've made me think about my setup again. When I have time, I will confirm my sub positioning once more. Cheers.
[This message has been edited by Lush (edited November 15, 2000).]
