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Discussion Starter · #1 ·
I recently upgraded my receiver from a HK AVR125 to an AV330, and was redoing all of my Avia/speaker/sub calibrations this past weekend.


One thing I have noticed is that if I set the volume to -15 for 75db for pink noise, when I move to the bass management 20-200Hz sweeps, the SPL ends up around 85db in the same volume setting. Then on the LFE-only sweep, the SPL is about 75+/- at the same volume setting.


Are these bass tones supposed to be dialed in to the same SPL level as the pink noise tones? So does that mean that the acoustics in my room are giving me huge room gain for the bass tones?


Can anyone enlighten me?
 

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I may be misunderstanding you, but if you are trying to set your subs level relative to your mains, you need to use the section where the noise alternates between the LF and sub, not the sweep.
 

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Discussion Starter · #3 ·
Okay, then my sub volume should be fine, if that's the case. I was just wondering about the big difference in SPL between those test tones (10db +/-) and the 20-200Hz sweep, and if it was supposed to be like that, or if it was just my room.


On the sweeps, if I turn the sub off, I get bass plenty below my xo point, but it is about 10db higher than the SPL I get with the pink noise tones, etc. I'm just wondering what's going on there.


Thanks.
 

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cyberbri: You gonna post your in-room plots of the H-100 for the rest of us? Please! :)
 

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Discussion Starter · #5 ·
I might, although it won't be soon. We're going back to Seattle for a week on Saturday, for my 10yr HS reunion.


If I do, I'll also post a sketch diagram of my room dimensions/layout, because that will play a huge factor in how the sound might differ from my room to other people's.


I know that for my room at least, it seemed a little boomy when it was near the rear left corner. Now I have it behind my couch, near the middle of it, facing the back wall - about 5-6' between back of couch and back wall. This seems to give me the smoothes t frequency response.



If you have any suggestions on ready-to-go charts I could download somewhere and just plug in numbers, that would be great. Also, I to do this I would use the Avia LFE-only tone, correct?
 

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Quote:
Originally Posted by cyberbri
Okay, then my sub volume should be fine, if that's the case. I was just wondering about the big difference in SPL between those test tones (10db +/-) and the 20-200Hz sweep, and if it was supposed to be like that, or if it was just my room.


On the sweeps, if I turn the sub off, I get bass plenty below my xo point, but it is about 10db higher than the SPL I get with the pink noise tones, etc. I'm just wondering what's going on there.


Thanks.
I don't think you can compare pink noise SPL with a sine wave.


Your crossover is not a brick wall, you will continue to get a diminishing signal after the crossover point. That's the main reason that your speakers should be able to reproduce a flat signal for about an octave below your crossover point. It's also the reason that setting phase is so important on your sub as sub and mains will be playing simultaneously at times.
 

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Discussion Starter · #7 ·
cecaa850,


So you're saying it's fine if the different tones give different SPL levels?


And yes, I knew that crossovers weren't brick walls, but I didn't realize how long (frequency) it took for the sound to roll off. It's not so bad when you're crossing mids/highs, but between the woofer and sub, if a 100Hz crossover point still gives you bass down to 40Hz, that can be a bit surprising (the first time you "discover" it). That's a big range at that level.


So is an octave a halving/doubling? So 1 octave down from 200Hz is 100Hz, and 1 octave down from 80Hz is 40Hz, and 40Hz to 20Hz?
 

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All crossovers are different. Normally they are rated at dB/octave. In other words a crossover using a 6dB/octave slope would not fall off as fast as a crossover using a 12 or 24dB/octave slope.
 
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