REW hook up and set up help

[wackii]

Hi, this is my first time using REW. I'm trying to get the FR measurements for my subwoofer. I'm having trouble on how to set this up correctly. I got an error on "Set Input Volume" setting. When I clicked on "Set Input Volume" button. The comp is playing the pink noise tone for like 2 secs, then it will prompt a message saying "Input volume control is at its maximum....Wizard was not able to get the input signal RMS level to -18db even the volume control at its max setting..." Why is that? Please help. Thanks in advanced.

Al,

Edit: I'm using SB live! (not the 24bits live! but the older version) if that helps.

[brucek]

When I clicked on "Set Input Volume" button. The comp is playing the pink noise tone for like 2 secs, then it will prompt a message saying "Input volume control is at its maximum.

So you've used the SET MEASUREMENT LEVEL to play the pink noise and you adjusted your receiver to show about 80dbSPL on your Radio Shack Meter..

Then you've clicked the SET INPUT VOLUME and does the VU meter respond to the signal?

If not:

Is your souncard selected in the select device pull-down?
Do you have LINE_IN selected in the pull-down?
When you tap or speak into the RSmeter (it's a microphone), does the VU meter and SPL readout respond?

brucek

[wackii]

So you've used the SET MEASUREMENT LEVEL to play the pink noise and you adjusted your receiver to show about 80dbSPL on your Radio Shack Meter..

I did that part... set it to 75db though

Then you've clicked the SET INPUT VOLUME and does the VU meter respond to the signal?

I did not see the VU meter respond... maybe my sound card line-in is incorrect.

Is your souncard selected in the select device pull-down?

yes

Do you have LINE_IN selected in the pull-down?

yes

When you tap or speak into the RSmeter (it's a microphone), does the VU meter and SPL readout respond?

I did not check that... I will double check everything again.

Thanks for the help Bruce.

Al,

[wackii]

I got it to work Question is how come the corrected sub graph is the same as the measured sub graph? I thought C weight should be compensated? Do I need to download the C weight compensated values? Thanks.

Al,

[brucek]

Question is how come the corrected sub graph is the same as the measured sub graph?

The corrected graph is the result that will be achieved (in theory) after a BFD filter(s) is added.

Add a filter and you'll see that the corrected graph changes.

brucek

[wackii]

I see. How about the compensate values for the C-weight? Is it already applied?

Al,

[brucek]

I see. How about the compensate values for the C-weight? Is it already applied?

In the REW pull-down 'METER', there is a checkable entry to turn on C-weight compensation. The C-weight is applied outside the frequency boundaries of the meter calibration file when a calibration file is loaded.

You can read all about this and more in the REW HELP files. You should give these a read. They're really well written.

brucek

[Sonnie]

If you are using a correction file (*.cal file)... hopefully you are... then don't even concern yourself with C-weighting. It's really not going to matter whether you have it on or off. There is no significant C-weighting compensation above 100hz (-0.3 @ 125hz) until you get up to 5khz where it begins to compensate more than a db.

[wackii]

Thanks. One more question: How come my soundcard response graph looks like the u shape (not flat like the help file mentioned)? Eventhough I have cleared the calibration data and unchecked the c-weight compensate. Thanks.

Al,

[brucek]

Eventhough I have cleared the calibration data and unchecked the c-weight compensate

So the Calibration appeared to be successful, and then you selected the LEFT tab and left the loopback in place and did an Automatic Measurement with no cal file and C-Weight unchecked and you got the U shape?

brucek

[wackii]

Yeah, the calibration is successful. I'm just curious why my soundcard response graph is not flat like the help file mentioned. I did unchecked the c-weight compensation and also clear the calibration file as the help file stated.

Al,

[wackii]

Here is the graph for my sub after EQ.



It's a sonotube 300L ported avalanche 15 powered by QSC RMX850.

Al,

[Sonnie]

That looks pretty wicked Al

[wackii]

Sonnie,

The bass is pretty wicked especially down low. The machine talks in Matrix Rev isn't the same anymore. Awesome.

Al,

[wackii]

I've just did some more EQing with my sub. Here's the update graph:

Thanks to REW making EQing jobs much easier and save lots and lots of time It'll probably take me a week to do this manually, instead of 1 hr i spent ealier Awesome software. Thanks.

Al,

[azjimmy]

Wackii
Nice work. Nearly flat to 10Hz and at 90 db to boot. Thats quite a sub.
Jim

[wackii]

Thanks. I'm really impress with this sub. It still have lots of headroom left. I calibrated the SPL meter to 80db and got that.

Al,

[Mitch G]

wackii wrote:

I got it to work Question is how come the corrected sub graph is the same as the measured sub graph? I thought C weight should be compensated? Do I need to download the C weight compensated values? Thanks.

Al,

Not fair! You didn't explain how you got it to work?

I realize this is an old thread, but I'm having the same problem.
Using an SB Live! I'm able to set the Measurement Level (at 75db on the meter display).
But, when I do the Set Input Volume, I get the message about volume at maximum.

I hear the pink noise. I see the SPL meter reading on REW change as the noise is played. But, then the message about max volume comes up.

Suggestions?

Thanks,


Mitch

[brucek]

I'm able to set the Measurement Level (at 75db on the meter display)

Try 80dB - does it make any difference?

brucek