12db per octave, -3db, -6db? What does it mean? - AVS Forum
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post #1 of 9 Old 03-08-2011, 07:41 AM - Thread Starter
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i read the stickie about "Terminology questions", but still didnt understand it, or even know if it applies here.

So I have installed in-wall and in-ceiling speakers that I got from Monoprice (they sound incredibly good FYI). I have my Yamaha 765's crossover set at 80hz, and all the speakers set to "small". My question is, what does the crossover that is built into each speaker actually do? I have them set at 0db, with the other options being -3db and -6db. I have tried switching to the other settings, and cant tell any difference. Am I supposed to hear a change?

FYI-I just ordered a BIC F12 to round out the setup, as my old SONY sub just aint cuttin it.

~Shaun
Yamaha RX-V765 / PSB B5's Fronts / PSB C4 Center / Micca R-65 In-Ceiling Rears / BIC F12 Sub
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post #2 of 9 Old 03-08-2011, 08:38 AM
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A speaker with a -12db per octave crossover would be one specified to reduce or attenuate output by 12db every time the frequency either doubles or halves from the designated crossover point.

Say you have a 2 way speaker that crosses over between the woofer and the tweeter at 1000hz with a -12db slope, the woofer will still move at 2000hz but it will be 12db quieter than it was at 1000hz.

There isn't enough information in your post to discuss the 0, -3db, and -6db settings you've configured.
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post #3 of 9 Old 03-08-2011, 02:36 PM
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I think he is refering to seeing the -3 dB on frequency responce tables. That means that between say 40Hz-20kHz, the volume will not deviate more than 3 dBs. In theory.

Sounds good!
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post #4 of 9 Old 03-08-2011, 03:36 PM
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This is what confused me
Quote:
I have them set at 0db, with the other options being -3db and -6db.
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post #5 of 9 Old 03-08-2011, 03:48 PM
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Quote:
Originally Posted by jmichaelf View Post
This is what confused me
Based on them being in-wall, my guess is that those are LF boundary compensation settings for room tuning and have nothing to do with the primary crossover configuation.
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post #6 of 9 Old 03-08-2011, 08:35 PM
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I am guessing that this is the setting that the OP is talking about:
http://www.monoprice.com/products/pr...t=1#largeimage

-Max
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post #7 of 9 Old 03-09-2011, 11:00 AM - Thread Starter
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Quote:
Originally Posted by maxcooper View Post

I am guessing that this is the setting that the OP is talking about:
http://www.monoprice.com/products/pr...t=1#largeimage

-Max

That is it. However that is on the front of the 6 1/2"s, the 8" in-ceilings have that switch (setting) on the rear. For the in-walls it is on the front. You can see the switch in the pictures.

~Shaun
Yamaha RX-V765 / PSB B5's Fronts / PSB C4 Center / Micca R-65 In-Ceiling Rears / BIC F12 Sub
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post #8 of 9 Old 03-09-2011, 11:36 AM
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Quote:
Originally Posted by border411 View Post

So I have installed in-wall and in-ceiling speakers that I got from Monoprice (they sound incredibly good FYI). I have my Yamaha 765's crossover set at 80hz, and all the speakers set to "small". My question is, what does the crossover that is built into each speaker actually do? I have them set at 0db, with the other options being -3db and -6db. I have tried switching to the other settings, and cant tell any difference. Am I supposed to hear a change?

Your in-ceiling speakers have two drivers in them, a midwoofer and a tweeter, coaxially mounted. There is a crossover for them built into the unit. See the blue circuit board in the photo of the back side. This has nothing to do with the crossover in your Yamaha receiver that handles bass.

The close-up photo of the switch shows the options as +3, 0, or -3 db. My guess is that switch allows you to adjust the volume of the tweeter relative to the midwoofer. If your ceiling speakers sound too bright, try -3 db. If they are not bright enough, try +3 db. If you can't hear a difference, leave them at 0.

Don't worry if you can't hear a difference, the differences will probably be subtle.
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post #9 of 9 Old 03-11-2011, 04:54 AM - Thread Starter
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Ok...thanks.

~Shaun
Yamaha RX-V765 / PSB B5's Fronts / PSB C4 Center / Micca R-65 In-Ceiling Rears / BIC F12 Sub
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