Strange noise with REW...

**n737nc** · **10-07-08, 06:22 AM**

When I click on measure, it starts up fine, then I get a "thud" noise, then continues through the measurement just fine. The "thud" noise is at the very beginning of the measurement, and giving me false readings below 10hz. I know that's nothing to worry about, but I don't like the noise everytime I do a measurement. Anyone have any ideas?

Heres a graph...I think that peak at 7hz is where the "thud" noise ends. As I said, it happens right at the very beginning of the measurement.

**thsmith** · **10-07-08, 09:02 AM**

n737nc

Have you calibrated your sound card ?

change your graph axis to the standard of:

Vertical = 45dB-105dB
Horizontal = 15Hz-200hz.

**n737nc** · **10-07-08, 09:23 AM**

I'm going to pick up a new sound card today. I'm still using the Sound Blaster Live External, and I'm now running Vista. Some say it works, other say no. So to play on the side of caution, I'm going to pick up the Turtle Beach sound card Bruce mentioned. There's a Fry's by my house, so I'm gonna see if they have it in stock.

I'll post more info after that. Maybe thats the root of the "thud" problem?

Nick

**thsmith** · **10-07-08, 09:31 AM**

Yep, an excellent soundcard, I use that one as well.

**Rick Auricchio** · **10-07-08, 05:53 PM**

That's similar to the behavior I get with the MacBook Pro. I get one to three clicks at the beginning of the sweep. It happens with either the built-in line output or the FireWire 828MkII device.

**JohnM** · **10-07-08, 06:05 PM**

The thud could be your drive unit hitting the end stop. Try changing the sweep start to 10Hz or higher.

**Rick Auricchio** · **10-07-08, 06:11 PM**

It's just a click for me, no driver cones slapping. I can even hear it in the MacBook Pro's little onboard speakers.

The click changes with output-buffer size, between one and three clicks depending on the buffer setting.

I suspect somewhere in the system there's some noise generated during open() or write() operations.

Starting the sweep even at 100Hz still gets the clicks at the start of the sweep.

**iove** · **10-07-08, 06:39 PM**

I was experiencing the same thing yesterday. At first I thought it was the woofer bottoming out and it continued to do that after I turn down the level signficantly.

Took me awhile, but I found that by turning off the power saver mode and turing on high performance, and removing an undervolt program I was using solved the thud sound.

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