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Discussion Starter · #1 · (Edited)
This is somewhat frustrating.

Calibrated my xonar HDAV sound card and the calibration appeared to spit out fine as shown below, 1st image.


But when I set the cal file to xonar for the sound card and radioshack for the mic I get this dropoff at 17hz, 2nd image.


Changing both files to radioshack I get a result that runs to my upper limit that I tested it too, 1st image.
One thing I noticed when opening the xonar cal file though is that the correction tables show zero for everything above 17hz. The ratshack shows values above and below that. For the life of me I can't figure out why there aren't values above 17hz.
 

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Certainly seem to have ended up with some odd data in the soundcard cal file. The soundcard response is flat enough that you can simply run without a soundcard cal, but it would be useful to figure out what has gone wrong. If you look in the REW log files (the location is shown in the About box) you may find one of the files has an error message from the time the soundcard cal was created, if that is the case please attach that log file here.
 

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Sidenote:

I am really confused about the bottom two graphs (both are titled "SPL & Phase No Smoothing")
Even considering the difference in the Horiz and Vert scales > these two bottom graphs vastly different?
(bottom graph looks good, but the middle graph seems to have issues, or could be my interpretation?)
 

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Discussion Starter · #4 · (Edited)
Ok so after messing around with my setup again here is what I have.

I noticed that when I cal'd everything in the first post it was off of the left channel, I had set the speakers to large so that I would get a full range out of the channel. Noticing this I change the connections so that I would measure off of the LFE channel set my lfe cros to 250hz. So I calibrated everything and labeled the soundcard cal file to xonar 2. I got result in the first image.
http://www.hometheatershack.com/forums/attachment.php?attachmentid=31435&stc=1&d=1306983096

I then re-ran the sweep and got the opposite that I got from what I got yesterday, 2nd image. No output below 17hz but output above 17hz.
http://www.hometheatershack.com/forums/attachment.php?attachmentid=31436&stc=1&d=1306983096

I have attached both of my soundcard cal files. Just to re-iterate xonar cal is off the left channel and xonar cal 2 is off the lfe channel, I made certain to switch from sat to sub when I did the calibration IIRC.
Xonar (off of Left channel)
http://www.hometheatershack.com/forums/attachment.php?attachmentid=31437&stc=1&d=1306983096
Xonar cal 2(off of LFE)
http://www.hometheatershack.com/forums/attachment.php?attachmentid=31438&stc=1&d=1306983096
 

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Your attachments are not showing up.

I noticed that when I cal'd everything in the first post it was off of the left channel, I had set the speakers to large so that I would get a full range out of the channel.
That was the right thing to do and the loopback measurement is fine.

Noticing this I change the connections so that I would measure off of the LFE channel set my lfe cros to 250hz.
Probably not a good idea.

How is your system connected to the xonar? Do you have a receiver in the system or is this an HTPC setup?

Repeating my previous post: The soundcard response is flat enough that you can simply run without a soundcard cal, but it would be useful to figure out what has gone wrong. If you look in the REW log files (the location is shown in the About box) you may find one of the files has an error message from the time the soundcard cal was created, if that is the case please attach that log file here.
 

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Discussion Starter · #6 · (Edited)
f you look in the REW log files (the location is shown in the About box) you may find one of the files has an error message from the time the soundcard cal was created, if that is the case please attach that log file here.
I fixed the attachments in the previous post, I can't seem to upload the soundcard .mdat files though(the calibration result files).



Onto the log file and the about box, I can't seem to locate the about box. I see a comment box with the following information listed.

sound card default
Sample rate: 48000 Hz
-3 dB points: 79.8 Hz, 18.220 kHz
Input device: Microphone (ASUS Xonar HDAV 1.3
Input: No input selected
Channel: Left
Input volume: no control
Input RMS target: -20.0 dB
Actual RMS at 1 kHz: -99.0 dB
Output device: No device selected
Output: No output selected
Sweep level: -20.0 dB
20 Hz .. 20 kHz flatness: +0.1, -65.8 dB

Soundcard LFE
Sample rate: 48000 Hz
-3 dB points: 999.4 Hz, 1.000 kHz
Input device: Microphone (ASUS Xonar HDAV 1.3
Input: No input selected
Channel: Left
Input volume: no control
Input RMS target: -20.0 dB
Actual RMS at 1 kHz: -57.8 dB
Output device: Speakers (ASUS Xonar HDAV 1.3 Audio Device)
Output: No output selected
Sweep level: -20.0 dB
20 Hz .. 20 kHz flatness: +27.9, -62.3 dB



When I select the cal files though it lists out the values on the right hand side with the dB and corresponding value. I'm sorry if I am being dense with this but I have dug around REW 5 and haven't found the about box. Oh I am running analog outs for my htpc, with that being said, I used soho54's calibration dvd to set my levels. After I had that figured out I then checked my output levels in rew and adjusted my volume slider so that I wouldn't clip, I ran my range from 2-100hz and I set my crossover to 250hz so it wouldn't interfere in anyway as i have a nasty dip at 80hz. I have a minidsp that I would like to use with rew to get things flattened out a bit.
 

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The About... box is in the Help menu.

Make sure you clear the soundcard cal, having a meter cal file loaded there means you double up on all the meter corrections, which is wrong. The soundcard cal files have .cal extensions rather than .mdat.

You cannot create a soundcard cal file using a limited range output, such as the one from the subwoofer output. REW uses the level at 1kHz as a reference for the cal file, with a sub output the 1kHz level is way down in the noise.
 

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Discussion Starter · #8 ·
Whoops didn't see the locations in the help file but I went digging around in there and didn't find any log files or errors.

So a question regarding the rat shack meter, I've noticed that I can clip signal when I check levels by rotating the dial. When I calibrated the sound card I set the volume level so that it wouldn't clip and ran the calibration. I left volume level the same and checked the levels again with the rat shack meter and this was where I could clip it out if I didn't rotate the dial, what I noticed is that I had to set the dial to 100db I wouldn't clip. Doesn't rew run cals at the 80db range though cause I could have sworn when I watched the readout on the ratshack meter I would get a 60-80db range. The results that I get shifted up and down but it appears they are the same.

I will try and regraph them this morning.
 

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Discussion Starter · #9 · (Edited)
Here is my graph, I kept the volume level the same and only changed the dial on the rat shack meter. The highest trace is 120, 2nd 110, 3rd is 100, and the bottom one was set to 80 as those were some of the values that I saw. The 80 clipped barely clipped the meter, like within .3db of clipping.
 

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So a question regarding the rat shack meter, I've noticed that I can clip signal when I check levels by rotating the dial. When I calibrated the sound card I set the volume level so that it wouldn't clip and ran the calibration. I left volume level the same and checked the levels again with the rat shack meter and this was where I could clip it out if I didn't rotate the dial, what I noticed is that I had to set the dial to 100db I wouldn't clip. Doesn't rew run cals at the 80db range though cause I could have sworn when I watched the readout on the ratshack meter I would get a 60-80db range. The results that I get shifted up and down but it appears they are the same.
The levels you use for calibrating the soundcard are likely to be different to those you use for making measurements.

When measuring there are two main places clipping can occur. The first is in the SPL meter, the meter's output has a limited range and if the acoustic level in the room is too high the output can reach its limit - with an analog meter that roughly corresponds to the needle on the meter hitting the end stop. The meter's 80dB range should generally give you plenty of headroom, make sure that the meter does not get pushed to the end stop when making measurements, if it does try reducing the sweep level. The other place clipping can occur is at the input to the soundcard. REW can detect that as the values reach the maximum, you should adjust the input volume so that the "Headroom" figure REW shows during a measurement is never lower than 1dB and ideally is not lower than 3dB.
 

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Discussion Starter · #11 ·
The meter's 80dB range should generally give you plenty of headroom, make sure that the meter does not get pushed to the end stop when making measurements, if it does try reducing the sweep level.
thanks, I dug through rew guides but I couldn't find what the rack shack meter should be set at.

I have a minidsp at the house and XLR cables so i am going to attemtp to flatten out the response especially with that major dip at 80hz(that was a result of the room because i went up and did a near field measurement of the woofer and didn't have the dip).


So I will have more questions in the future but I am at the hospital taking care of my new baby girl :)
 

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Discussion Starter · #13 ·
ok so I finally got a chance to play around with my minidsp last night and it works pretty well.

The only problem is that I can't get rew to output an automatic calibration. I can manual calibrate with rew and then upload to the DSP but when I have tried to follow the steps on mini's site I get all zero's in the text file.
 

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Do you mean REW is generating a set of filters OK but you are not able to export them using "Send filter settings to equaliser" or REW is not generating the filters in the first place?
 

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Discussion Starter · #15 ·
Do you mean REW is generating a set of filters OK but you are not able to export them using "Send filter settings to equaliser" or REW is not generating the filters in the first place?
REW does not auto EQ first. I set everything to auto but I have tried closing out and also saving the EQ file, when I save everything set to auto all the values are zero. I then sent the filter settings to the EQ and minidsp did nothing as it should. Minidsp was just a flat line


I then attempted to EQ by my own, send the files to the eq, and then uploaded tot he minidsp. Minidsp then showed the filter response changing.



So I am missing a step somewhere and its around the auto step. Someone mentioned that when you get to the auto step rew should be performing some steps and I should see it output values or doing auto calculations. I haven't see that part and I have tried messing around at the eq filters step, setting them to manual setting them to auto, saving the file, closing out of the window but I can't find or locate a selection that says run auto settings.
 

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The Auto/Manual selection for filters just controls whether REW is allowed to set the values or not. To request REW to generate filter values you need to make sure the target is the correct shape for the speaker type and at the correct level, then click "Match Response to Target" in the filter tasks panel. REW will then work out filter settings that will being the current measurement in line with the target. There is info about the various EQ window controls in the help.
 
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