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Discussion Starter #1 (Edited)
Hello room,

I have a Mac Pro Dual 2.8 running 10.5.6, Motu 828 mk1, and I'm doing exactly as the "Choosing audio input and output" states. I connected the R side of the main outs to the Channel 4 input on the Motu 828 line ins. (According to the help guide, it says do not us an input that is also a mic input). Line ins 1 & 2 are Mic/Line inputs. That's why I used line in 4. In the Audio Setup of the MacPro Dual 2.8, I have the Motu 828 set as the default audio device. In REW, my input and output device is set to "default device". The sampling rate is 44.1 KHz, input channel is "right". "Use left channel as calibration reference" is UNCHECKED. When I click "check levels", my output flutters between -11.8 and -12.0 which is fine according to the guide. My inputs however, doesn't exceed -82.1 and thats with the volume control for line in 4 on the MOTU turned all the way up. Please help, somebody. I've completed treating room with bass traps and broadband absorption and would like to know wher I stand with response, RT60, etc. The room sounds good but I wanna see what the stats are of my room.
P.S. Do I have to use the line in and out on the Mac Pro for anything? What am I doing wrong.

Signed, Sitting in front of screen waiting for a reply, help, anything..
 

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Discussion Starter #3
Thanks for responding, I tried that also. "MOTU 828" appears in the input device drop down but not the output drop down. Still, no luck. However, I did get a level when I connected the R main output to the R Mic/Line input on the MOTU which the guide says do not do. In audio setup, I have the "Monitor input" set to Monitor input 2, (which is the Mic/Line input). Every time I take a reading with this connection, a report is generated that says "Impulse response is not correct. It must be corrupted". What am I doing wrong?

Signed, still in front of the lcd waiting for a solution. Please help!!!
 

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Discussion Starter #5
I dont exactly remember where but it stated not to use a mic/line input if the input has phantom power. Is it allright to use it? Mic/Line input 1 & 2 seems to be the only inputs I can get a input level on, (of course with phantom power turned off) however, for it to get high enough, I have to turn on "monitor input" from the motu audio setup and then I can use the monitor volume to adjust. I still get the error that says "Impulse response not where it shoud be, it must be corrupted".
 

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it stated not to use a mic/line input if the input has phantom power. Is it allright to use it?
It's fine as long as you turn off the phantom power (which is used when the mic is connected).

I have to turn on "monitor input"
No, you don't want any monitor mode turned on.

Just connect line-out to line-in and do your soundcard cal. Then remove the loopback and hook up your mic and receiver and do your measurement.

brucek
 

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You can use the Mac Pro Line In and Line Out instead of the Motu, just make sure they are set as the defaults in the Mac preferences before starting up REW. On a more general note, a combined mic/line input is fine in its line setting, it is typical laptop mic inputs which are not suitable.
 

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For the loopback cal, yes, for measurement you'll need break outs to connect to your mic preamp and amp.
 

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On my Mac G5, the Mic inputs on the front panel are treated as the default L/R inputs for recording.

You might try setting up your Motu with the Aggregate Device feature and then see if you can't get all the in's and out's to work with the aggregate device selected in REW.
 

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Discussion Starter #12
Will report back and let you know my results. What could the reason be for not getting a high enough level when the line input is turned all the way up? I thought this would all b a piece of cake.

Signed, playitbyear
 

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Discussion Starter #13
I dont have a mic pre or amp. Running active KRK V8's on main outs of the MOTU 828. This is why i thought it would b a piece of cake. I'm not using the BFD or any EQ. I just want to measure frequency response and RT60 of my room. Mac Pro Dual 2.8, 10 Gigs, MOTU 828, Digital Performer 6.01, Reason 4.01. No BFD, EQ, etc.
 

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Oh, also open up your MOTU software where you can adjust the volumes and submixes (can't remember the name off the top of my head...just know what the icon looks like). There you have the option to set inputs to line level or mic level (which is about a 14dB swing on volume).
 

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Discussion Starter #15
Okay room, got levels, error message once again says "impulse response not where it should be, the measurement may have been corrupted. I'm running the r side of my main outs to the r side of my mic/line on the MOTU 828. Still, no luck!! Therer aren't any monitors hooked up, no other connections, etc. Am I missing something? Should I have some other connections going on?

Signed, lost
 

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Is the 828 a FireWire card? Java apps (like REW) cannot access the inputs of FireWire-connected soundcards (thoguh they can access the outputs). Try the Mac Pro's on-board Line In, assuming it has one.
 

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Discussion Starter #17
Okay, now were getting somewhere. So that means that I should connect the MOTU 828 output to the Mac Pro "line in". Then, in REW, input device should be set to "Line in" and the Output device should be set to "MOTU 828". Correct?
 

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Discussion Starter #18
Hello room, JohnM,

Thanks for that bit of info. Ran the output from tho MOTU 828 to the line in on the Mac Pro. Worked just fine. Flat with some roll of at the very low end and hi end of the spectrum. So, being that REW doesn't recognize the inputs on the MOTU 828, do I connect the output of Radio Shack SPL meter to the input on the Mac Pro to measure the response of the low end in my room? I'm not using the BFD or any other outboard in aiding the bass response in my room. I have extensive absorption in my room and would like to know the response of the low end. Is that connection that I mentioned above the right connection to measure my room. However, depending on the results, I would include in the path a Rane PE15 Studio Parametric Equalizer. How would I connect this?

Signed, coming along Thanks!!
 

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Yes, connect the SPL meter to the Mac Pro line in. If you put the equaliser in the chain it would go between your Motu outputs and your monitors.
 

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Discussion Starter #20
So I should run the SPL "Out" to the Mac Pro "In" and take measurements, if I include the equalizer, should I run the SPL "Out" to the equalizer "In", "Out" from the equalizer to the Mac Pro "In"? Lastly, I have files of pink noise that spans from 10Hz - 300 HZ in 1Hz increments, a file that has pink noise from 40Hz - 80Hz, a file that is 500Hz - 2.5KHz and a file that has 20Hz - 20KHz. The monitors will be connected to the outs of the MOTU so that the SPL meter can measure the pink noise which will go into the Mac Pro "in" which will be recorded into REW, Correct? And then to make corrections if needed, make adjustments to the EQ and re measure, right.
 
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