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How loud is a test tone from REW

post #1 of 13
Thread Starter 
When generating a test tone, you select volume level -20 dB, -10 dB, 0 dB etc. With an audyssey calibrated AVR, how loud will it be at listening position? Will a 0 dB signal and 0 dB on the AVR be 105 dB ?

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post #2 of 13
How loud the sweep tones will play depends on the volume control for your receiver or preamp. You should set the volume to be fairly loud, but not so loud it hurts your ears or risks damaging your tweeters. If you have an SPL meter, 85 dB is about right. The quote below from my Audio Expert book explains more.

--Ethan
Quote:
Originally Posted by The Audio Expert 
The tones must be fairly loud to drown out the ambient room noise by at least 30 or 40 dB. Nulls 30 dB deep or even more are common, especially in rooms having little or no acoustic treatment. So if the ambient room noise is only 20 dB softer than the sweep at a null frequency, the true null depth will be hidden and filled in by the background noise. The tracking filter built into REW mentioned earlier helps reduce stray noise, but it’s better to deal with this at the source.
post #3 of 13
I use the Dayton USB measurement MIC, and I notice it is a quiet MIC since I have to increase the volume considerably before REW says the test tone is of acceptable volume (avr volume at around -3 to -5db). My frequency response registers at 100-105db for the peaks. Now your question made me wonder if a frequency response's graph can be affected solely by the volume? Since some speakers seem to sound better and more accurate when at higher volumes...
post #4 of 13
Thread Starter 
Quote:
Originally Posted by Ethan Winer View Post

How loud the sweep tones will play depends on the volume control for your receiver or preamp. You should set the volume to be fairly loud, but not so loud it hurts your ears or risks damaging your tweeters. If you have an SPL meter, 85 dB is about right. The quote below from my Audio Expert book explains more.

--Ethan

I think you misunderstood my question. What I'm asking is how loud the REW tone signal is (from the single frequency tone generator), when played through an audyssey calibrated receiver. All receivers should play the signal at the same volume if it is properly calibrated with audyssey. I'm asking how loud the 0 dB tone generated by REW is, basically what is the "reference" level of a generated tone from REW?

To reword it:
Assume audyssey calibrated receiver, and an absolutely perfectly flat FR curve from 0 hz to 20 khz.
If I play a 25 hz tone, or any single frequency, from REW, at a level of 0 dB, what will the measured SPL be at my listening position, if the receiver is set to 0 dB?
post #5 of 13
Thread Starter 
Quote:
Originally Posted by brandon_k_w View Post

I use the Dayton USB measurement MIC, and I notice it is a quiet MIC since I have to increase the volume considerably before REW says the test tone is of acceptable volume (avr volume at around -3 to -5db). My frequency response registers at 100-105db for the peaks. Now your question made me wonder if a frequency response's graph can be affected solely by the volume? Since some speakers seem to sound better and more accurate when at higher volumes...

What I'm asking doesn't involve peaks, it should be a constant volume level as it is just a singular frequency, at a constant power, generated by REW.
post #6 of 13
I'm assuming it'll be at whatever your speaker's efficiency is rated at. With the avr set at 0db, something like klipsch speakers will register a higher db than something like my aperion speakers.
post #7 of 13
Thread Starter 
Quote:
Originally Posted by brandon_k_w View Post

I'm assuming it'll be at whatever your speaker's efficiency is rated at. With the avr set at 0db, something like klipsch speakers will register a higher db than something like my aperion speakers.

no, because audyssey calibrates the channel levels based on how loud it is at LP, so if your speakers are efficient or ineffecient they will be the exact same volume on an avr that is calibrated.
post #8 of 13
Quote:
Originally Posted by WagBoss View Post

I'm asking how loud the 0 dB tone generated by REW is, basically what is the "reference" level of a generated tone from REW?

REW has its own playback volume level in the software, so that's one factor. Another is the output level from your sound card. So the answer to your question "how many volts does REW output?" is "it depends." biggrin.gif

--Ethan
post #9 of 13
Thread Starter 
Quote:
Originally Posted by Ethan Winer View Post

REW has its own playback volume level in the software, so that's one factor. Another is the output level from your sound card. So the answer to your question "how many volts does REW output?" is "it depends." biggrin.gif

--Ethan

I use hdmi out, and where is the playback volume level in REW located? Do you mean the -99 dB FS to 0 dB FS meter? I'm asking at 0 dB set on REW and on the calibrated AVR.
post #10 of 13
I've never used HDMI audio with REW. But again, REW has its own output level. Click the measure button in REW to show the "Make a measurement screen," then find the output level adjustment in the middle of the row of adjustments.

--Ethan
post #11 of 13
I'm checking the REW V5 Help (PDF) file (can't run REW right now, I'm at my REW computer but far away from my devices). Both output level and input level (or sensitivity) options for REW are set in the Soundcard Preferences panel, which is the first panel (tab) of the Preferences dialog box. There are two output level controls that can be set from Soundcard Preferences: Wave Volume, which is typically set to the maximum of 1.000, and Output Volume, which also has a maximum of 1.000 and should be set as needed.

See the figure on page 123 of 154 in the REW V5 help file.

Also, to get the maximum amount of control over your soundcard level settings in REW, make sure the most "specific" entries for your soundcard are selected in the "Output Device and Output", and "Input Device and Input" list boxes in Soundcard Preferences, and the check boxes "Control output mixer/volume" and "Control input mixer/volume" are checked.
Edited by Sonic icons - 7/14/13 at 4:18pm
post #12 of 13
Quote:
Originally Posted by Sonic icons View Post

I'm checking the REW V5 Help (PDF) file (can't run REW right now, I'm at my REW computer but far away from my devices). Both output level and input level (or sensitivity) options for REW are set in the Soundcard Preferences panel, which is the first panel (tab) of the Preferences dialog box. There are two output level controls that can be set from Soundcard Preferences: Wave Volume, which is typically set to the maximum of 1.000, and Output Volume, which also has a maximum of 1.000 and should be set as needed.

See the figure on page 123 of 154 in the REW V5 help file.

Also, to get the maximum amount of control over your soundcard level settings in REW, make sure the most "specific" entries for your soundcard are selected in the "Output Device and Output", and "Input Device and Input" list boxes in Soundcard Preferences, and the check boxes "Control output mixer/volume" and "Control input mixer/volume" are checked.

Exactly. The test tones, sine waves, pink noise etc is all the same as anything else your laptop puts out. It's controlled by the sound card settings.

Now some exceptions would be source material that is crappy...... but normally, there will be a consistent output level whether it be REW or 'new mail notification' . etc.......
post #13 of 13
This is simple.
When you calibrate in REW, you set the db level to a reference db level, usually measured with a RS mic.

So, if you calibrate your test tones to be 75db, they will be. If you calibrate them to be 85db, they will be.

If you have a very quiet room with low noise floor, then taking sweeps at 75db may work ok, but most people calibrate and take sweeps at 85db.


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