Manual Readings 1st time help needed - Home Theater Forum and Systems - HomeTheaterShack.com

 
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post #1 of 6 Old 01-19-11, 11:27 AM Thread Starter
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Sam
 
Join Date: Feb 2007
Location: Rochester NY
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Manual Readings 1st time help needed

I just did the manual with mp3's that I downloaded and this is what I came up with. The blue line is without any Audyssey corrections and the pink line is with Audyssey . Big time screwups with Audyssey don't you think? I have it crossed over to my mains at 80.

This is with my 18.2.2 IXL ported with the Onkyo TX-SR707. I have a FBQ2496 that I took out of the loop for this reading.

Any ideas on why Audyssey is so far off?

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post #2 of 6 Old 01-19-11, 12:02 PM
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Bill
 
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Re: Manual Readings 1st time help needed

With software like REW available (and you are in the REW forum), I would not trust measurements at a few fixed frequencies. The log sweep measurement technique is much more reliable and informative.

You can see a sample of Audyssey results in this thread.

You did not mention which microphone you are using. If you are not using an individually calibrated mic, I would not trust the results below ~20Hz.

When you wrote that you took the FBQ2496 out of the system, should I assume that you ran Audyssey setup after removing the FBQ?

What speakers were you driving for your test? If you were driving two (or more) front speakers, much of the difference you see in average level between the sub and the mains is attributable to multiple channels combining electrically in the sub, and interfering in the room. To compare levels, be sure to drive just one front channel with the sub.

When measuring Audyssey, be sure DynEQ is off, as this will provide a gradual boost as the frequency gets lower. My guess is that you did have it off from your graph.

Bill
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post #3 of 6 Old 01-19-11, 12:22 PM Thread Starter
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Sam
 
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Re: Manual Readings 1st time help needed

Thanks for answering...
Quote:
laser188139 wrote: View Post
With software like REW available (and you are in the REW forum), I would not trust measurements at a few fixed frequencies. The log sweep measurement technique is much more reliable and informative.

You can see a sample of Audyssey results in this thread.

You did not mention which microphone you are using. If you are not using an individually calibrated mic, I would not trust the results below ~20Hz.

I am using the 33-4050. The spreadsheet I used has the figures for that mic already built in

When you wrote that you took the FBQ2496 out of the system, should I assume that you ran Audyssey setup after removing the FBQ?

I had read to measure sub first, make corrections with BFD next, then run Audyssey. Am I wrong?

What speakers were you driving for your test? If you were driving two (or more) front speakers, much of the difference you see in average level between the sub and the mains is attributable to multiple channels combining electrically in the sub, and interfering in the room. To compare levels, be sure to drive just one front channel with the sub.

I have Rocket 760's with a bigfoot center, QS8 surround and Rocket 250's for the rear. I had them all on when testing the subwoofer. Again, I am wrong here?

When measuring Audyssey, be sure DynEQ is off, as this will provide a gradual boost as the frequency gets lower. My guess is that you did have it off from your graph.

Yes, it was off, maybe the only thing I did right?

I tried using rew with my laptop and an external usb soundcard. I couldn't even get that calibrated correctly so I gave up.

So, what should I do, if you can help?

Bill
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post #4 of 6 Old 01-19-11, 01:42 PM
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Bill
 
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Re: Manual Readings 1st time help needed

Quote:
Sepen wrote: View Post
Thanks for answering...

I am using the 33-4050. The spreadsheet I used has the figures for that mic already built in ...
Whichever generic Radio Shack adjustments are in the spreadsheet, the mics themselves vary at the low end, below ~20Hz, and at the high end, above ~3-4kHz. Although I've not seen a large statistical study of the RS meters, there is no reason that their manufacturing tolerances are tighter than the ECM8000 or EMM-6 microphones. You can get some idea of the variation amongst those in the graphs on the mic calibration page.

Quote:
Sepen wrote: View Post
... I had read to measure sub first, make corrections with BFD next, then run Audyssey. Am I wrong? ...
That's right, but you wrote that you removed the FBQ2496 from the system. Obviously if it was in the system when you ran Audyssey setup, then you removed it from the system in order to measure Audyssey alone, your graphs won't tell you very much that's useful.

Quote:
Sepen wrote: View Post
... I have Rocket 760's with a bigfoot center, QS8 surround and Rocket 250's for the rear. I had them all on when testing the subwoofer. Again, I am wrong here? ...
Only if you are trying to compare the levels in the sub graph to the levels above the crossover, and concluding that the sub is not calibrated even with the mains. If you are trying to visually confirm that the levels are even, you need to drive only one speaker along with the sub.

Quote:
Sepen wrote: View Post
... I tried using rew with my laptop and an external usb soundcard. I couldn't even get that calibrated correctly so I gave up. ...
That's probably the problem you want to solve first, although I may not be the best resource for that as I have had no soundcard issues with the Dell desktop and laptop systems I have used, so I have no hands-on experience with external USB soundcards.

The advice above about measuring Audyssey still applies, even with REW. I'm just passing on the lessons I learned from having made all those mistakes myself when I started.

Regards,
Bill
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post #5 of 6 Old 01-20-11, 06:46 AM Thread Starter
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Sam
 
Join Date: Feb 2007
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Re: Manual Readings 1st time help needed

Thanks Bill,

I dabbled with rew afterwards and did get the soundcard calibrated correctly. Now I need to get some pieces for the cables at Ratshack today and will attempt to get things going. Again thanks for taking the time to explain things to a newb.
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post #6 of 6 Old 01-20-11, 07:14 AM
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Join Date: Dec 2010
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Re: Manual Readings 1st time help needed

www.monoprice.com sells the cables as well for alot less....if you're interested.
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