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Discussion Starter · #1 ·
Okay, so i'm on the first step of calibrating the levels for the loopback. I'm using a M-Audio Profire 2626. On the software mixer for the m-audio I can see the "mixer out" is correct at -12db. I can match the -12 db on the input loopback also with the gain on the preamp at about 1/4 of the way up, and its not clipping. However, in the Room EQ program it is only reading -30.8 for an input. if I try to bring the gain up on the Profire it clips and will not go past -19 db. The highest it will go without clipping is about -22 db, whereas the m-audio mixer software reads that at about -1db. So basically it seems like the levels are not matched.

Any ideas with what's going on here?

Thanks so much
 

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tbuck92 said:
Okay, so i'm on the first step of calibrating the levels for the loopback. I'm using a M-Audio Profire 2626. On the software mixer for the m-audio I can see the "mixer out" is correct at -12db. I can match the -12 db on the input loopback also with the gain on the preamp at about 1/4 of the way up, and its not clipping. However, in the Room EQ program it is only reading -30.8 for an input. if I try to bring the gain up on the Profire it clips and will not go past -19 db. The highest it will go without clipping is about -22 db, whereas the m-audio mixer software reads that at about -1db. So basically it seems like the levels are not matched.

Any ideas with what's going on here?

Thanks so much
- I'm finding the underlined portion of your quote fairly vague, ( ie; where are you seeing this level matching occuring ? ).
- As a result, I don't know whether or not you're trying to use M-Audio(s) software mixer to try to control the input levels from the M-Audio card before the signal shows up at REW .
- FWIW, If you are attempting this, then I don't believe you can actually accomplish that as a goal .
- More importantly, ( if I've guessed correctly at what you're doing ) then I believe you've actually engaged a "no-no" in signal routing ( since you might merely be sending the input signal back out the output & then back in again because of your hardwired loop-back, & so on & so on ) .
- This will create a "Feedback Loop" that will have all the ( described ) characteristics that you mention towards the end of your quote ( as in , when you try to turn up the input gain within REW, the input level seems to be on a hair-trigger & that it simply "jumps" into clipping ( as you attempt to "gain-up" ) .

- See my pic ; ( it's obviously from a different soundcard than yours , though this should suffice for demonstration purposes ) .




- I don't know what options (tabs ) your M-Audio software mixer offers ( a few screen-shots would be nice ) but if you look closely at the picture I've posted , the tab being used ( for my Fast-Track Ultra ) is called "Monitor 1/2" .

- Typically, "Monitoring" is ( another name for ) a musicians foldback mix ( routed to headphones or the playback speakers ) . That's typically what these M-Audio (mixer tabs) are used for ( ie; creating 2 track monitor mixes ) .

- I have yet to see an M-Audio software-based control mixer that actually intercepts the digital stream and allows attenuation on the input of that digital stream ( before it shows up at the audio application ) .

- Typically, all the input control ( for gain or attenuation ) is found at the front-end hardware ( preamp ) , as well as the attenuation offered within the audio app. ( REW , ProTools, etc ) .

<> EarlK
 

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Discussion Starter · #4 ·
Hi,

thanks for the response. Im using windows 7 64bit with SP1. This is an image of the problem I am having. The output appears correct at -16db on the software mixer. I adjusted the pre-amp on the profire 2626 to match the input to the output level. They both measure at -16db on the mixer but on REW software the input is reading at -36db. Please advise. thanks


www (dot) i55.tinypic (dot) com/2lnw977.png
 

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Check the level controls in the properties for that input in the Windows sound controls, there may be an additional level control there.
 

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Discussion Starter · #6 ·
I checked that, and there doesn't seem to be any additional controls. There's gotta be a setting somewhere that's making it do this...
 

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Indeed, the REW levels are exactly 20dB down so it suggests there is a control somewhere that is causing that. On the plus side you will be able to make measurements anyway as the measurement method is pretty robust, but you will likely get warnings from REW about levels being lower than they should be (which you can ignore).
 
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