Can't get a nice graph!

[Plecto]

Hi. I've just gotten my hands on Room EQ Wizard and I though it would be cool to make a graph which could show my sound systems week and strong spots, but I can't get it to work. There is a graph, but my radioshack is just bouncing up and down and the graph makes no sence at all. Could someone tell me what's wrong?

[brucek]

Your graph is just noise.

Are you able to first create a soundcard calibration file?

[Plecto]

How do I do that?

I don't believe it's just noise, I can see that the radioshack is bouncing up and down, it jumps +-10db all the time, but it is accurate if I just play a sinus tone.

[brucek]

Good idea to read the REW HELP FILES before you begin. It's all laid out quite nicely.

brucek

[Plecto]

I've allready read some of it. I read a norwegain guide as well, I downloaded the calibration file for my radioshack and checked the c-weighting box, but It didn't help much. I tryed again and set the start at 0hz. The graph shows that my fronts has a peak effekt at about 20hz

But why is the meter on the radioshack's screen jumping up and down when playing a rising tone from 0hz to 500hz? Shoudn't it be rather evenly rising? It's because of this I don't believe that this has anything to do with the software settings.

[brucek]

You need to start out by creating a soundcard calibration file. This tells a lot about what works and what doesn't.

brucek

[Plecto]

Tested from 0-20000hz. I read that this shoud have been an even line, whats wrong?

[brucek]

Have you created a soundcard calibration file?

[Plecto]

Yes, and I used the calibration file at settings-mic/meter, but there were no difference.

[JohnM]

When you play a sweep through your system the level on the meter will vary because of the effects of resonances and reflections in your room. You can see the same by playing a sine wave and changing its frequency. From the plots you have posted the signal from your meter is not getting to REW, which could be a problem with the soundcard mixer settings or with the cables you are using or how things are connected up. A good starting point for getting the connections right is making the soundcard calibration file, if that is a nice smooth line that looks like the ones in the help file and only looks like that when you have the external loopback connection in place all should be OK there, but it would be a good idea to post the result you get so that we can check it for you. After that is OK the next thing to look at is the connection to the meter.

[Plecto]

Yea, I posted the soundcard graph, and it's not exactly a smooth line. What can I do to fix this? Is it somekind of software or settings that is messing things up?

[JohnM]

Ah, that was the soundcard test. It looks like either the external loopback connections on the soundcard are not right or the soundcard settings are not right to listen on the input the loopback is connected to. Are you on Windows? If so, XP or Vista? You need to make sure your soundcard is set as the default device for audio playback and recording, on Windows that is done via the Audio tab in the Sounds and Audio Devices item in the Control Panel. You then need to make sure your soundcard's line input is selected as the input source, how you do that depends on your soundcard so we need to know what it is. Note that you cannot use a mic input.

[brucek]

Are you using stereo plugs on both the line-in and line-out jacks on the soundcard?

[Plecto]

Are you using stereo plugs on both the line-in and line-out jacks on the soundcard?

Yupp.

Now that I changed from mic to line-in, the graph looked a little better:



But I'm still not satisfied if I test the speakers as I did earlier. This graph is still jumping up and down, but it is climbing more realistic than it did before. So the problem could be resonances in my room, what could I do to fix this? Change the possition of the speakers?

I have Windows Vista btw.

[JohnM]

Yes, trying different speaker and different listening positions is the best first step in getting a smoother response.