UFX Crossover question

fookgub · May 4, 2004, 10:17 AM

I've just downloaded the UFX plugins, and I noticed something odd while I was messing around with the crossover plugins. If I hook up a noise source to the crossover (either version), then check the outputs with a peak detector, the high frequency output consistantly show peaks of about +5.8dB, regardless of the crossover frequency. The low frequency output never gets above 0dB, as expected.

So my question is, am I performing a valid/useful measurement, and, if so, couldn't this be a potential source of lots of distortion?

I'm very new to this forum and kX in general, so please excuse me if this has already been answered.

**dj_stick** · May 4, 2004, 10:21 AM

try testing this with a normal wave file like an mp3 song

fookgub · May 4, 2004, 11:03 AM

Wow, thanks for the fast reply!

I tried it with a few mp3's and found that I can still reproduce the same effect, but it is largely dependent on the crossover frequency. If I set the frequency to 8000Hz, the high-pass output stays well below 0dB. At the other extreme, 40Hz, the peak detector shows between +1 and +5dB depending on the song. A typical value of 2000Hz does produce positive peaks on a few tracks, but not most. It seems to depend on the high frequency content of the song, with more high frequencies leading to larger peaks.

I've compared the highpass output to the lowpass output and the unprocessed wave, and the effect seems to be confined only to the high pass portion. I couldn't get either of the other two above 0dB no matter how hard I tried.

In defense of the crossover plugins, I'll say that the ouput doesn't sound distorted. Maybe the peak detector is picking up distortion outside the audible range. Or maybe everything is fine and I just don't understand what the peak detector is trying to show me.

Anyway, I posted a screenshot showing basically how I've been conducting these experiments:
http://www.ece.utexas.edu/~wrobert/Clipboard.jpg

If you see anything wrong, or have any other comments, let me know.

Thanks.

**dj_stick** · May 4, 2004, 11:15 AM

the testing looks accurate enough
however it may be a bug w. the crossover plugin… try using the dynamics processor between the output of the compressor and the epilog, and use the preset "limiter"
that should fix your problem

Max M. · May 4, 2004, 11:43 AM

see
http://www.hardwareheaven.com/showthre...threadid=26207
http://www.hardwareheaven.com/showthre...threadid=21815

**dj_stick** · May 4, 2004, 01:06 PM

thanks max i will make a note to add this to the kb

fookgub · May 4, 2004, 07:36 PM

that clears everything up for me. thanks.

May 4, 2004, 10:17 AM	#1
fookgub DriverHeaven Newbie Join Date: May 2004 Posts: 6 Rep Power: 0	UFX Crossover question I've just downloaded the UFX plugins, and I noticed something odd while I was messing around with the crossover plugins. If I hook up a noise source to the crossover (either version), then check the outputs with a peak detector, the high frequency output consistantly show peaks of about +5.8dB, regardless of the crossover frequency. The low frequency output never gets above 0dB, as expected. So my question is, am I performing a valid/useful measurement, and, if so, couldn't this be a potential source of lots of distortion? I'm very new to this forum and kX in general, so please excuse me if this has already been answered.

May 4, 2004, 11:03 AM	Thread Starter #3
fookgub DriverHeaven Newbie Join Date: May 2004 Posts: 6 Rep Power: 0	Wow, thanks for the fast reply! I tried it with a few mp3's and found that I can still reproduce the same effect, but it is largely dependent on the crossover frequency. If I set the frequency to 8000Hz, the high-pass output stays well below 0dB. At the other extreme, 40Hz, the peak detector shows between +1 and +5dB depending on the song. A typical value of 2000Hz does produce positive peaks on a few tracks, but not most. It seems to depend on the high frequency content of the song, with more high frequencies leading to larger peaks. I've compared the highpass output to the lowpass output and the unprocessed wave, and the effect seems to be confined only to the high pass portion. I couldn't get either of the other two above 0dB no matter how hard I tried. In defense of the crossover plugins, I'll say that the ouput doesn't sound distorted. Maybe the peak detector is picking up distortion outside the audible range. Or maybe everything is fine and I just don't understand what the peak detector is trying to show me. Anyway, I posted a screenshot showing basically how I've been conducting these experiments: http://www.ece.utexas.edu/~wrobert/Clipboard.jpg If you see anything wrong, or have any other comments, let me know. Thanks.

May 4, 2004, 11:43 AM	#5
Max M. h/h member-shmember Join Date: Dec 2002 Location: Evil Empire Posts: 2,639 Rep Power: 69	see http://www.hardwareheaven.com/showthre...threadid=26207 http://www.hardwareheaven.com/showthre...threadid=21815

May 4, 2004, 07:36 PM	Thread Starter #7
fookgub DriverHeaven Newbie Join Date: May 2004 Posts: 6 Rep Power: 0	that clears everything up for me. thanks.