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Discussion Starter · #1 ·
Bryan and All,
Yes thanks so much for the video, I am really excited to get going on some measurements! I am having a problem getting REW to recognize the ART USB Mobile Pre for inputs or outputs. I have got my Audix TR40 to work through it but only by changing the input in OSX system preferences. Can someone please send me in the right direction to help with this? I'm sure there is info in other places of the forum that I haven't seen.

Thanks!

James
 

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Re: REW YouTube Tutorial

DexPro,

> The "ART USB Dual Pre" utilizes the computers ( both Windows & Macs ) built in generic USB drivers ( so no special driver software is loaded ) .

> Once the unit is plugged in , it'll initialize ( by its very presence ) the OS(es) generic USB drivers, which will be called something like "USB Audio CODEC" within the sound control panel for either OS .

> Because of this ( "generic" situation ), you won't find the "ART" specifically named/identified within any of the sound control panel's selection boxes ( or within REW ) .

> Simply select , "USB Audio CODEC" within the sound control panel and keep this choice as your default sound driver .

> Within REW, choose "Default" for both input & output device .

NOTE :
> To avoid creating a "feedback loop" such as you reported in another post ( read page 6 of the users manual ) & set your "Mix Control" to "computer" ( fully "clockwise" ) .

:sn:
 

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Discussion Starter · #3 ·
Re: REW YouTube Tutorial

WOW, thanks so much for the help... we're rolling.

Thanks Again,

James
 

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Discussion Starter · #4 ·
Re: REW YouTube Tutorial

Earl K,
Thanks again for the help with the cal file. I'm having an issue of getting the input to show levels when I'm doing the "check levels" step. I know the mic is working because when I turn the com/preamp pod I get feedback. I'm running the pink noise at 75db like it said but nothing is showing on the input meter. You we're so helpful last time I thought I'd bug you again.

Thanks

James
 

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Re: REW YouTube Tutorial

Hi James,

<snip> I'm running the pink noise at 75db like it said but nothing is showing on the input meter.
> How do you know you're getting 75db ( at the test mics position ) from your speakers ?

> Have you turned on the 48V phantom power that your Audix test mic needs ?

> Are you sure you've turned up enough gain on the appropriate channel ( on your ART soundcard ) ?

> When you're "checking levels" , just how high up the input meter does the signal indicator show ?

> I can't understand how you could make a successful soundcard calibration , yet have this much trouble getting signal into the ART .

> Perhaps you should display a pic of the soundcard calibration that you made .



:sn:
 

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Discussion Starter · #6 ·
Re: REW YouTube Tutorial

Earl,
I was able to get this to work by selecting "built in input" on the input box list. I checked to Mae sure that this was the Audix mic through the art pre and it was. So I want to make s measurement and got a loopback similar to the one I got when I was trying to do the calibration the first time. Not sure how to get rid of that. I double checked everything use suggested and got the same results. I'll post the calibration later when I get back to my computer.

Thanks!

James
 

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I was able to get this to work by selecting "built in input" on the input box list. I checked to Mae sure that this was the Audix mic through the art pre and it was. So I want to make s measurement and got a loopback similar to the one I got when I was trying to do the calibration the first time. Not sure how to get rid of that. I double checked everything use suggested and got the same results. I'll post the calibration later when I get back to my computer.
Wow James, ( no doubt you just can't see how garbled & incoherent the quoted paragraph actually reads ) .

No matter, if what you just tried to articulate is , that you're still having a "feedback" issue while making measurements ( & the ARTs "Mix" knob is set fully clockwise to "computer" ) then you must have another "feedback route" engaged ( allowing input to flow back out to the output creating a problem ) .

Open up your Macs "Audio MIDI" Control panel and make sure that the "Thru" boxes ( within the input section ) are not checked . This one simple box ( when checked ) will allow feedback to be created and that will spoil all your measurements.

Here's what the panel would look like if you were using an M-Audio "Mobile Pre" .



:sn:
 

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Hey guys,
Just got my ART USB dual pre as well. I plan to use it with the dayton emm-6 mic and REW on my Mac. What settings do I need configured on the ART (level, gains, phantom power, etc)? From the info above it looks as if the Mac OS X settings have been mentioned. Anything else I may need to know?

Thanks.
 

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What settings do I need configured on the ART (level, gains, phantom power, etc)? From the info above it looks as if the Mac OS X settings have been mentioned. Anything else I may need to know?
  • Phantom Power ; Keep it turned off until you are ready to test a speaker ( ie; "off", while calibrating the soundcard ) .
  • Gain ; The USB soundcard has gain controls ( on the front ) that are adjusted according to the suggested signal needs of the software . REW has those "needs" spelled out within the software itself , as well as in the Help Guides .
  • Level ; Acoustic measurement levels should be made in the range of 80db ( C-weighted ) at the mic position . If you don't have an SPL meter, turn the level up to "just" make normal conversation incoherent .
  • etc. ; The are a lot of etc(s) in this field / if you want to make usable measurements you'll need to devote some time & money to the pursuit of that knowledge .
  • Anything else I may need to know ; Fully study post 2 and prepare to study some books & articles written by acousticians .

Here's a good one to read .

:sn:
 

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I am already pretty familiar with taking measurements with REW and interpreting them, I just recently went from the RS SPL meter to a mic and preamp setup instead.

Do I need to calibrate the ART pre? I dont have a way to connect the input to the output since ones a mic cable(balanced) and the others a 1/4"?
 

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I wasnt able to calibrate the ART pre (need to order the correct cable) but I did mess around and took some measurements, not sure how accurate they are though.



For some reason the mics not picking up much sound below 100hz? These do not really reflect my past measurements with my RS SPL meter? The SPL's seem high although the actual sound is not nearly that loud either. My SPL meter shows 70db?

Previous measurements with RS SPL meter (Same setup)
 

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If you change the soundcard (or even the input level) you need to redo the REW SPL meter calibration so that REW knows how the new levels in the data it is seeing relate to SPL in the real world.

The graph you posted looks like it came from a speaker set to "small", with 80Hz bass management high pass applied.
 

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If you change the soundcard (or even the input level) you need to redo the REW SPL meter calibration so that REW knows how the new levels in the data it is seeing relate to SPL in the real world.

The graph you posted looks like it came from a speaker set to "small", with 80Hz bass management high pass applied.
I thought I did calibrate the SPL levels but maybe not. Im using the latest Mac OS build and theres the icon for SPL meter, I selected calibrate and used the mic to measure the volume and adjusted the volume in the other box that had popped up to be the same as the reading? Suggestions?

As for the measurements, first, how important is it to calibrate my ART soundcard, and secondly, I do cross my Towers over at 80hz, but why the odd results? Previous measurments with my RS meter were way different as shown above?
Edit- I do have a sub in the mix thats why I'm surprised at the odd measurement
 

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So I tried more configurations and still no luck. It seems like somethings not working on the preamp? When I am under preferences trying to check the levels using the REW sub/speaker signal, the L&R meters rarely dip below -35 and even when I move the mic around or disconnect it, the values really dont change at all?

Somethings not right, any suggestions?
 

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Somethings not right
Well that's an undertatement .

Make sure the default soundcard setting ( within the Macs audio control midi panel ) is set to it's own generic USB driver .



FYI, set both sampling rates to read the same ( 48K ) / unlike this pic .

:sn:
 

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Well that's an undertatement .

Make sure the default soundcard setting ( within the Macs audio control midi panel ) is set to it's own generic USB driver .



FYI, set both sampling rates to read the same ( 48K ) / unlike this pic .

:sn:
Ill try that. 48k in REW too?
 

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48k in REW too?
Yes, you should make the effort to match sample rates between all hardware & the software using the hardware ( the "matching" will help avoid resampling issues ) .

:sn:
 

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Yes, you should make the effort to match sample rates between all hardware & the software using the hardware ( the "matching" will help avoid resampling issues ) .

:sn:
Thanks for the help but I am still stuck:( I tried your settings and this time, no reading on the L&R meters when calibrating? I am about ready to give up on the ART pre in favor of the external sound card and preamp(Xenyx 502). Do the 502's have phantom power now?

Unless there's something wrong in my approach, I am not sure what avenue to chose. Previously I had zero issues using my soundcard and RS SPL meter with REW.
 

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Plug your mic into the ART, turn on the phantom power , turn up the gain on the appropriate input channel on the ART & then open &view the Macs audio control panel . After choosing the generic USB input ( in that control panel ) do you see any meter movement when you speak into your test mic ?

If so , then you ought to be able to get that signal into REW .


Unless there's something wrong in my approach, I am not sure what avenue to chose. Previously I had zero issues using my soundcard and RS SPL meter with REW.
If you can't get your soundcard working with REW , go back to what was working ( would be my suggestion ) .

:sn:
 
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