REW "Left Channel" Calibration Question

[jaz123]

Hi -

I've been lurking on this forum ever since my SVS PB12/+2 arrived. Based upon the good info here I purchased a BFD and soundcard (soundblaster 24 live external) and dowloaded the latest version of REW. I made a single attemp at EQ of my sub a couple of days ago. Everything seemed to go as described in the REW guide other than when I "checked" my soundcard calibration by selecting the left channel on the REW dashboard and repeated the calibration. The REW documentation says that I should see a nearly flat response but all I see is random noise. The initial cal I ran on the right channel appears to be fine.

I'll also note that the only channel that I had jumpered (souncard input to output connected) is the right. Should I have jumpered the left channel as well before perfroming the check?

Any advice would be appreciated.

[Julien43]

I'll also note that the only channel that I had jumpered (souncard input to output connected) is the right. Should I have jumpered the left channel as well before perfroming the check?

Hey Zig!

I'm new here too, so maybe some once else can chime in

I think that you have to have the channel "jumped" because REW measures the difference between the input and output to determine the response error/cal file

Try it and see. "Un-jumper" the right channel and "jumper the left when running a left channel card cal in REW and see if you get acceptable results

I hope that helps

Julien

[jaz123]

Thanks Julien ...... I'll give it a try.

John

[brucek]

I'll also note that the only channel that I had jumpered (souncard input to output connected) is the right. Should I have jumpered the left channel as well before perfroming the check?

Any advice would be appreciated.

The soundcard calibration and the regular response testing is accomplished all on one channel. Usually we choose the right (for no good reason).

If you were able to finish the soundcard calibration and get a graph that appeared reasonable, you would then save that file. This correction is then applied to the graphs to remove any anomolies in the soundcards response. You do have to load the calibration file by using the appropriate pull down in REW, but after that it loads automatically every time REW is loaded.

When you did the check to see if you get a flat response, hopefully you still had the jumper from line-in to line-out hooked up. It should then have worked fine.

Once that check is done, remove the jumper and use your regular cables. Again, this is all done on the right channel.

brucek

[JohnM]

The reference in the help files to selecting the Left channel to check the cal doesn't refer to the channel of the soundcard, but to the measurement tabs in REW (i.e. Left, Right, Centre etc).

[jaz123]

Thanks John & brucek

Everything did appear to work fine on the right channel. As John points out (and what wasn't clear to me in the guide) is that the left channel reference was to the REW tabs not the left/right radio button on the left side of the REW dashboard. I was actually able to complete a sweep and flatten a few peaks but I wanted to make sure that I was doing everything right.

Now it's on to some fun with house curves!

John