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Discussion Starter #1 (Edited)
I'm new to REW as the title suggests, but not new to audio, however I am having a tough time getting the connections made so that can move calibrating the sound card (SC) and beyond. At this point I don't have a BFD, but I will soon. I want to take some measurements of my room. This is my goal currently.

I am using a Denon 3808ci Receiver. My question is how to take measurements not using a BFD in the loop? More specifically, which connection do I use on the Denon 3808ci from the line out of the Turtle Beach Audio Advantage SRM? Currently I have the line out going from the Audio Advantage SRM going to the 3808ci front panel AUX Input Right Channel.

What volume should I set the receiver at?
What db level should I set the RS 33-2050 at?

At this point, do I need to hook the subwoofer up, or can I with what I have.

Things I've already done:
  • Downloaded, installed REW
  • Installed Turtle Beach drivers, and REW "sees" it.
  • Made all the connections in the Help diagrams, with the exception of the subwoofer, and to the receiver. Because I'm not sure which to use.
  • Hooked up RS 33-2050 SPL Meter on tripod.
  • Loaded .cal into REW, but not the RS 33-2250 xls. file that I downloaded in the download section. Does that file do anything?
Again, I do not have a BFD yet, but would like to take some measurements of my room.

I have yet to make a connection to my subwoofer. Or if I even need to make a connection at this point, if I'm only taking measurements?

Any help you guys can provide would be appreciated. Thanks.
 

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Read this connection guide for hookup information.

Remember before you hook anything up to your system or use the SPL meter, you must do a soundcard calibration to produce a soundcard.cal file that REW will use to compensate for weaknesses in the cards response. See the REW HELP FILES for that routine.

Once that's complete, connect to the receiver (not the sub) into the AUX or CD input. Some people use a Y-splitter there to get both mains running. Always have the receiver in stereo mode (not direct) with all soundfields and effects shut off. Use the standard crossover frequency you regularily use (i.e. 80Hz)

You don't need a BFD to use REW. REW is a measurement tool for your system. Matters not that the system has a BFD.

The XLS file you downloaded is for people who don't want to use REW and want to manually enter sine wave tone values into a spreadsheet. Delete the file. The meter.cal file is to compensate for the SPL meters response inadequacies.


brucek
 

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Discussion Starter #3
brucek,
Thanks for the reply. That cleared up a few things for me. I'm off to do the soundcard calibration. I'll report back my findings.
 

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Discussion Starter #4
I've had a little time to play with the Audio Advantage today. Actually I spent the better part of the day trying to just get a sound card calc. file. I'm not sure I've got a proper calc file yet. At any rate this is what I've got. Let me know what you think.



With these settings.


I've followed the hookup diagram outlined in the REW Help files. Here's my setup:
Line Out Left -------> Looped back to Line In
Line Out Right -------> To AUX (split L & R) on Receiver

Line In Left ---------->Looped back to Line Out
Line In Right --------->Radio Shack SPL
 

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You're a bit confused on the hookup.

From the connection guide I referenced earlier it says in part:

The left channels of the soundcard are normally not used and are simply never connected. To compensate for any weakness in the soundcards response, we create a calibration file using the right channel of the soundcard, by use of a loopback cable and a special one-time-only routine that saves that file into REW. That loopback is removed after running that calibration routine and then the right channel is used for all testing.

Alternatively, you may loopback connect the left channel line-out of the soundcard to the left channel line-in of the soundcard, and use the right channel for measuring and this will serve as the soundcard calibration in lieu of a calibration file. To use this special feature, you must check the 'Use Left Channel as Calibration Reference' in the REW Settings page. I much prefer to use the soundcard cal file method. It's simpler, uses less cables and so less chance of problems, and offers a bit better S/N ratio. The Left channel calibrate method is best used once you've become familiar with REW and want to test System Delays.


So, start with the soundcard cal routine using the right channel and completely disconnect everything else. This is the only channel you'll use. Place the loopback on the right channel and run the routine. When done, use the right channel for the meter and receiver hookup with the loopback removed.

When you set up the levels for the soundcard routine, you must not clip them by having any red signal in the VU meter. Try to get the input around -12dB to -18dB, such as in the picture below. You have your input level slider up full. It needs to come way down. Watch the VU meters - no red allowed......
Check Levels soundcard calibrate.jpg

brucek
 

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Discussion Starter #6
OIC. Your right, I was confused. I removed all connections. I looped the Line I/O Right channel. Did the soundcard calibration "measure". Set the levels like yours. When it was done, I clicked the "Make Cal..." button to save the file. Using those settings this what I came up with.



With these REW/Audio Advantage SRM settings.



After soundcard cal routine was finished, I disconnected the right channel Line I/O, and hooked up radio shack spl to Line in, and receiver to Line out, Right channel. Nothing is on the left channel. I did split out the Line out going to the receiver just to have both channels working.
 

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Discussion Starter #7 (Edited)
Ok, I think I'm setup correctly.

Here is a graph of my first measurement. How does it look.


Anything I did wrong?
 

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Anything I did wrong?
All looks good except I think you have a level mismatch with your sub and mains.

Normally we first shut off the mains and run measures on the sub only to get an idea of how it looks without any other influence. Then you can move the positioning of the sub or add EQ or whatever to get the sub to roughly track the target that REW shows. (to shut off the mains simply unhook them with the power off)...

Then add the mains and see how they integrate with the sub around the crossover. You can adjust the sub or mains trim level to get them equal and also the sub phase at this point to get a smooth transition. You certainly don't have a smooth transition.......

brucek
 

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Discussion Starter #9
All looks good except I think you have a level mismatch with your sub and mains......(to shut off the mains simply unhook them with the power off).....You certainly don't have a smooth transition.......
Is there are an easier way to take the main out of the equation? My mains are a PITA to take out to the loop then put back. :bigsmile:
Then add the mains and see how they integrate with the sub around the crossover. You can adjust the sub or mains trim level to get them equal and also the sub phase at this point to get a smooth transition. You certainly don't have a smooth transition.......
brucek
If I change the subwoofer trim level to integrate better with the mains, will that have an influence on any of the mic calculations, SPL calibrations, soundcard calibrations, etc, that I set earlier when initially setting up REW?

In general are there settings I should leave untouched based on the initial setup with REW settings?
 

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Is there are an easier way to take the main out of the equation?
No, unless you have a separate amp for the mains, there's no way other than remove the cables from either the speaker or the receiver.
Usually the sub and mains levels are close already from setting up the level with the receiver test tones before you begin measuring.

will that have an influence on any of the mic calculations, SPL calibrations, soundcard calibrations
Whenever you alter levels you simply have to set up the Check Levels again. It won't have any effect on the soundcard calibration file or the meter file, but you need to run the Check Levels routine again... only takes a second.

brucek
 

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Discussion Starter #11
No, unless you have a separate amp for the mains, there's no way other than remove the cables from either the speaker or the receiver.
Usually the sub and mains levels are close already from setting up the level with the receiver test tones before you begin measuring.
You mean, when the receiver is itself is setup? If so, :foottap: because I just remembered that I have yet to re-calibrate the receiver after a power outage some time back. So this may be the reason the mains, and sub are out of wack.

Could I remedy the situation, by calibrating the receiver using Audyessy. Then do a check levels, then run measurements? That should give me main, and subwoofer parity.

Whenever you alter levels you simply have to set up the Check Levels again. It won't have any effect on the soundcard calibration file or the meter file, but you need to run the Check Levels routine again... only takes a second.
brucek
No problem there. :T
 

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Could I remedy the situation, by calibrating the receiver using Audyessy. Then do a check levels, then run measurements? That should give me main, and subwoofer parity.
Yeah, running the auto EQ first seems to be the way to go if you have a BFD and Audyessy. After you have run the auto eq, run REW and see how it looks. Then add any BFD filters and remeasure.

brucek
 
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