How bad is my sound card?

[CZ Eddie]

I have a Realtek ALC888. It's a sound on motherboard device.



I'm using the optical output to my a/v receiver when watching movies.

For right now, as I learn REW for the first time, I hooked up the Line Out to the Line In via a stereo mini-DIN to stereo mini-DIN cable:



This is what I get when I calibrate my sound card. It looks a lot more squiggly than the other pictures I'm seeing posted around here. Is it do-able or should I scrap things and buy a real sound card?
I've got an M-Audio Delta-DiO which has optical in and out. But does not have analog in for the radio shack SPL meter.

[salvasol]

CZ Eddie wrote:

... I hooked up the Line Out to the Line In via a stereo mini-DIN to stereo mini-DIN cable:

I think that's the problem (using stereo cable) ... I think you have to use just the right side

Hopefully the experts will clarify that for us ...

Or it could be the setting ... you have something on that is supposed to be off ...

[brucek]

I've got an M-Audio Delta-DiO which has optical in and out. But does not have analog in for the radio shack SPL meter.

REW is designed to work in analog using a line-in and line-out.

I hooked up the Line Out to the Line In via a stereo mini-DIN to stereo mini-DIN cable:

Your soundcard will be fine, but you have to use the recommended cabling.

You require a breakout splitter that seperates the left and right channel of the line-out and the line-in. Then you connect a loopback on the right channel and run the soundcard calibration routine. The left channel is left open and not used.

See REW connection and Cabling Basics thread..

brucek

[salvasol]

brucek wrote:

You require a breakout splitter that seperates the left and right channel of the line-out and the line-in. Then you connect a loopback on the right channel and run the soundcard calibration routine. The left channel is left open and not used.

brucek

... I was right ... (it seems I'm not to old after all, I still remember some things )

[CZ Eddie]

brucek wrote:

Your soundcard will be fine, but you have to use the recommended cabling.

You require a breakout splitter that seperates the left and right channel of the line-out and the line-in. Then you connect a loopback on the right channel and run the soundcard calibration routine. The left channel is left open and not used.

Thanks for trying to help. I went to radio shack and spent $10 on a pair of stereo splitters, but it didn't help. I got the same results. Though it's green instead of red, if that means anything?
I'm connected exactly as it shows in this picture on the connections thread.

Actually, I have a VERY loud squeal (feedback) through my speakers whenever the SPL meter is turned on. So maybe something is funky somewhere. If I turn down the "playback volume" on my computer or turn off the SPL meter, then the feedback squeal goes away. It's a 90+db squeal. ouch.

http://www.hometheatershack.com/foru...-rs-meter1.jpg

Using these:

[brucek]

You've got a couple problems. One is the low end rising up and down and the other is the oscillation at higher frequencies.

The low end response can usually be corrected by extending the Impulse Response window a bit so that more of the response is included. Extend it until you get a smoother line.

To do this, run the soundcard cal routine and get to the spot where you are about to click Finish. Don't click Finish, instead click the IR Windows ICON in the upper right corner of the REW screen. A popup will arise and it will show the pre-window as 125msecs and the post window as 500msec. Extend the post window longer, and as you do, you'll see the Frequency Resolution result lowering. Change the window to something like 1000msec and click Apply Windows while watching your squiggles. See how it's smoother now? Hit Finish on the soundcard cal routine and save the file. Your measurements will be more accurate down lower now.....

The upper oscillations are often caused by the sweep level not being quite correct. Play with the level and see if you can clear it up....

brucek

[JohnM]

The squeal you hear is a feedback loop. Your line in is enabled in the playback mixer so what the input picks up gets fed to the output and gets picked up by the meter etc until you hear the squeal. Open the playback mixer and mute everything except Wave. There is no problem using a stereo cable for the loopback but you will need break outs when you get to making measurements.

[CZ Eddie]

brucek wrote:

<snipped everything I don't understand yet>

brucek

I'll read that over a few times.

JohnM wrote:

The squeal you hear is a feedback loop. Your line in is enabled in the playback mixer so what the input picks up gets fed to the output and gets picked up by the meter etc until you hear the squeal. Open the playback mixer and mute everything except Wave. There is no problem using a stereo cable for the loopback but you will need break outs when you get to making measurements.

Ahh, I found the mixer you are speaking of. It's not in my sound card control panel properties anywhere. But if you open the volume in the systray, then click on "mixer", you then get the mixer! I'll do as you suggest and try again.

I was playing the level adjustments and REW settings before I saw both of your posts, and somehow managed to pull this one out without hearing any feedback.

[CZ Eddie]

brucek wrote:

To do this, run the soundcard cal routine and get to the spot where you are about to click Finish. Don't click Finish, instead click the IR Windows ICON in the upper right corner of the REW screen. A popup will arise and it will show the pre-window as 125msecs and the post window as 500msec. Extend the post window longer, and as you do, you'll see the Frequency Resolution result lowering. Change the window to something like 1000msec and click Apply Windows while watching your squiggles. See how it's smoother now?

That did make it smoother.

Thanks, guys!

Here is the cal after it's been loaded.