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Discussion Starter · #1 ·
I have searched all over the net, but can't find the right answer. I know the theory behind white noise; but can't seem to set up correct subwoofer level using white noise.

I previously owned CA Azur 751R but sold it due this specific reason (Subwoofer Level Setting) despite its infectious SQ. Then I bought Onkyo 5010.

Since 751R has been discontinued my dealer offered me an absurdly low price I couldn't pass, so, bought it again.

Now I have two monsters (Onkyo 5010 and CA 751R). I have an FV15HP and a PSB S500. Using them as side tables by the main listening couch.

I'm having a real hard time setting up subwoofer level with CA 751R. The reason is CA uses white noise as internal test tones. While there is no problem to set speaker levels; the internal test tone (WHITE NOISE) for sub is so anemic that I have to dial the gain knob on FV15HP to at least 10 o clock to get 70dB on rat shcak spl meter. The sub trim level in avr is at 00. Same problem with PSB S500. Both subs lying almost right next to me.

All things equal, when I check sub levels with Onkyo 5010 using internal sub test tone (Pink Noise); the subs read over 82dB on SPL meter.

Both subs bottom out during playback at even -40 on the master dial on CA 751R despite SPL meter showing 70dB on either sub when I set the level with white noise. No such problems with Onkyo 5010 even at -10 on master volume.

How to set subwoofer level using White noise?? It is way off.
 

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White noise is typically not used for test tones, pink noise is. If you're indeed using white noise that's probably the problem.
 

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+1.

There are lots of online sites that provide test tones and various noise files you can use.

Note the Radio Shack, and most inexpensive (below several hundred dollar), SPL meters are C weighted and roll off below 30 Hz. You can find a compensation file online or use a different scheme (e.g. REW and calibrated mic).
 

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1)Have you tried the AUDY auto setup feature in the 751r?

2)Are you sure it is using "white noise" instead of "pink noise"? They will often sound similar in this context.

Tom V.
Power Sound Audio
 

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White noise consists of equal energy per Hz. It is randomly distrubuted across the spectrum. When you tune between FM stations (remember that?) without Muting, you will hear essentially white noise.

Pink noise consists of equal energy per octave.

WIth white noise. there will be as much energy from 20-40 Hz as there is from 10.00-10.02 kHz. In other words, the energy in the bass region is 1/1000th of the energy in the HF region.

Pink noise has as much energy from 20-40 Hz as it does from 10-20 kHz.

Pink noise is obtained by processing white noise with a -3 dB/octave filter. This "half-pole" filter is not easy to implement, usually requiring several R/C stages.

Pink noise, therefore, is what is used to measure frequency response with an RTA.
 

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Discussion Starter · #6 ·
1)Have you tried the AUDY auto setup feature in the 751r?
Yes I did but not much luck. Audyssey on this AVR is best left off.

2)Are you sure it is using "white noise" instead of "pink noise"? They will often sound similar in this context.

Tom V.
Power Sound Audio
Yes I am sure it is white noise.

This is from CA Azur 751R user manual page 18;

The basic process for manual adjustment is to listen to or measure with a
Sound Pressure Level (SPL) meter (more accurate and recommended but
not essential) the level of sound produced by each speaker and set relative
levels for each speaker so that they all sound the same loudness at the
normal listening position. The 651R/751R incorporates a Test Signal
Generator (broad-band white noise) to facilitate this.
 

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Discussion Starter · #7 ·
White noise is typically not used for test tones, pink noise is. If you're indeed using white noise that's probably the problem.
I'm bound to use white noise with CA 751R coz CA uses white noise as internal test tones. I have both Onkyo 5010 and CA 751R. Onkyo does have PN; while CA has WN.
 

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^^^

You can use external test tones with any AVR. ;)
 

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My question is why are you using the CA in favor of the Onkyo?? The CA only has Audyssey 2EQ, the Onkyo has XT32...seems like an easy choice to me. :confused:
 

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Discussion Starter · #10 ·
WIth white noise. there will be as much energy from 20-40 Hz as there is from 10.00-10.02 kHz. In other words, the energy in the bass region is 1/1000th of the energy in the HF region.
So what should be the corresponding SPL in 40-80Hz octave with white noise if same octave gives 75dB SPL with pink noise keeping all other variables (sub gain, room acoustics, listening distance) fixed?
 

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Discussion Starter · #11 ·
My question is why are you using the CA in favor of the Onkyo?? The CA only has Audyssey 2EQ, the Onkyo has XT32...seems like an easy choice to me. :confused:
Dear the trouble is ...... CA has fantastic sound; you just fall in love with it. YMMV but I love it.

I don't like what Audyssey does in my room esp with the sub response. I have always not relied upon auto eq systems. I've owned Yamaha 3900, Denon 3313, and Onkyo 809 in the past. I always liked pure sound with minor BFDing on the sub response. Even with sub, I prefer cutting the peaks and not boosting the dips.
 

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^^^

I used to feel the same way about Auto EQ...then I got XT32. ;)

Just sayin'.
 

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It's weird some subwoofer AVR generated tones are great, some others useless. One inside Sherbourne 7010 is useless, even if I increase all the way up- the dB meter hardly registers even though subwoofer is pounding away like crazy when you playback music. But Lexicon work well. Have had couple of other brands forgot what and those weren't great either.

Talking of which if I want to calibrate the sub from downloaded test tones, what should I use for the sub, and for the L/R to get levels correct? White noise for sub, pink for L/R? Set level on amp first to a specific volume ie 80dB with pink noise, L/R speaker on, but sub switched off. Then playback white noise- sub on, but L/R speakers switched off, then only adjust subwoofer dial?
 

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Discussion Starter · #14 ·
5010 does have MultiEQ XT32 with Sub EQ HT with independent dual sub calibration; but I never liked what it did with subs. That may have been due to my room.
 

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So what should be the corresponding SPL in 40-80Hz octave with white noise if same octave gives 75dB SPL with pink noise keeping all other variables (sub gain, room acoustics, listening distance) fixed?
For the same voltage reading (pink vs. white). with a 3 dB/octave HF boost on white noise, the 40-80 Hz octave would therefore be roughly 20 dB down from the HF octave (10-20 kHz). That's 1 watt of LF energy for every 200 watts of 5-20 kHz energy.

White noise is bad news for tweeters. They better have HF protection if you're applying white noise to the whole system while examining the LF response.
 

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^^^

I used to feel the same way about Auto EQ...then I got XT32. ;)

Just sayin'.
5010 does have MultiEQ XT32 with Sub EQ HT with independent dual sub calibration; but I never liked what it did with subs. That may have been due to my room.

Yes, I know your Onkyo has XT32, that was kind of my point....I would be using the Onkyo.

Are you certain you ran Audyssey the best you could (with regards to mic positions, using a tripod or mic boom, etc.) and set everything correctly afterwards (speakers to small, 80hz crossover, etc.)?

If you did do all that and still didn't like it, you could just turn it off and still have the benefits of the superior auto-setup in the Onkyo. ;)
 
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