Generator signal not continuous

**Torzel** · **02-27-09, 12:07 AM**

Fellow Shacksters I need your help.

I am trying to set up my 4 year old Toshiba Portege Intel Pentium M processor 2 MB RAM Windows XP and Creative SoundBlaster LX to do some measurements and I have followed all instructions to the T. However, ALL test signals and generator signals are discontinuous. There are multiple random interuptions and resumptions with each about 1-2 sec apart that is impossible to measure or adjust properly. I have tried quitting all other apps, suspending Norton, shutting off wifi, but the interruptions remain.

Does anyone have any ideas where the problem lies.

Thank you ahead of time.

**JohnM** · **02-27-09, 05:14 AM**

Have you tried changing the replay buffer size setting in the Soundcard settings? Are you running on battery or on the mains adaptor? If the processor has power-saving performance settings is it set for maximum performance?

**Torzel** · **02-27-09, 09:14 AM**

Thank you John. I increased buffer size to max, and it did not help. I'm running on full power and am plugged in.
I also tried the generator on the internal soundcard and it functioned perfectly. Then I thought the LX may be defective, so I played a music file on the LX and it ran fine. Somehow in REW, the LX soundcard has problems. Not quite sure why.
Thank you again for your suggestions.

**JohnM** · **02-27-09, 09:21 AM**

Is the LX plugged into a USB 2.0 port? The difference with REW compared to playing a music file is that data is going both ways, doubling the traffic on the USB. If the LX has settings for sample rate and sample width make sure they are set to 48kHz and 16 bit (rather than 96kHz and/or 24 bit).

You could use the internal card for replay and the LX for capture (assuming your laptop does not have a line in - if it does, just use that). Make sure both are set to the same sample rate.

**Torzel** · **02-27-09, 09:41 AM**

John,
The LX is plugged into USB 2.0 port. The sample rate is set to 48 kHz and 16 bit. I will try to use internal for replay and the LX for capture and I will let you know how it goes.
Thanks again for your suggestions. If you think of others while I toy around, please let me know.

**Torzel** · **03-01-09, 08:51 AM**

Hi John;

So I tried to use my laptop as source but the only line out is for headphones and the only line in is for a microphone. So I can't do the internal loop test (and I also lack the cabling). I reduced the screen resolution, and aborted some background processes, and I can get mostly unclipped (around 80%) with these changes. With Task Manager on the side, I can see that the clips occur when CPU usage hits 100%. I am very surprised that REW uses so much of the resources of the computer, which by no means is an underpowered unit. I have run IE, photoshop, illustrator, word all together and I have never come close to 100% CPU usage. Is there anyway to reduce how much resource REW uses? Also, I am surprised that no one else has had similar problems based on searching the REW forum. So there is something peculiar about my system.

Thank you John for your help thus far.

Have a nice weekend (I'm off to visit the in-laws for a few days and much to my chagrin I will be away from my system).

Shafie

**JohnM** · **03-01-09, 02:40 PM**

The headphone out can be used, but not the mic in. It is possible to use one device for output and another for input, if that helps any. REW resource usage is generally not especially high, especially during signal capture when it is just writing and capturing soundcard data. You could try a different sample rate in case the laptop is doing software sample rate conversion, and check that there are no sound effects or EQs of any sort active.

**Torzel** · **03-05-09, 12:31 AM**

Hi John;

I finally got it working. I uninstalled REW 4.11, downloaded REW 4.0, and installed 4.0 on my system. The older version, I guess, does not put as much of a demand on the system, so I was able to make the measurements without unwanted interruptions. I won't post these measurements just yet -- they are amazingly poor. This is not the room for the final set-up. We will move to that house April 1st. I will measure that room + speaker interactions and will post those results.

Thank you for all your help.

Shafie

**Torzel** · **03-07-09, 11:28 PM**

Hi John;
One more update. I was able to get version 4.11 of REW to work by uninstalling all the earlier JAVA updates (5 had accumulated on my computer). Now I am running REW 4.11 without a problem. The program is great. It's a very powerful program, but correctly interpreting the results is an art and a science. I am catching up on the science. I hope the art will come with experience. Measured my current hi fi system and compared it to my parents lo fi older system and the differences are small! Beside the Help file and this forum, is there another source for reading that you would recommend?
Thank you for your input, the program, and your time.

**JohnM** · **03-08-09, 08:30 AM**

Glad to hear it is working out. There is a great deal of information available to help you learn more about sound reproduction in the home. As a starting point for more general advice head to the Home Audio Acoustics forum and look through the resources on some of the acoustics manufacturers sites, e.g. the Education section of the GIK site: http://www.gikacoustics.com/education.html

**Torzel** · **03-08-09, 10:51 AM**

Thank you John for your recommendation. I'll head over there to see what I can learn.

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