A few questions to troubleshoot some UMC-200 issues

[jcisbig]

Greetings,

I've got a UMC-200 in my system that is giving me some trouble and I wanted to ask around here before calling in to customer support.

In the last few months, I've noticed a strange issue with my Subwoofer PEQ. For whatever reason the selected frequency for the PEQ filter is not accurate. For example, in order to affect the frequencies around 22hz, I have to select something close to 44hz in the processor PEQ in order to have it affect the 20hz region. The same goes for wanting to adjust something in the 40hz region, I have to select an 80hz filter in the processor. It's almost like I need to double the number of the frequency that I'm trying to address in order to actually affect that frequency. Any ideas?

Another issue, crossover slope. I was measuring some subs yesterday and changed the crossover slope from 24dB to 12dB and noticed no measurable difference in the subwoofer roll off above the 80hz crossover point, which is obviously weird.

There are a few anomalies like this that are giving me frustration. Are there any ideas for quick fixes or things to check? I'll probably end up needing to reset the firmware or something, but I wanted to ask first.

Thanks!

[Gary Cook]

The cross over is not a point, it's a slope, 12db (or 24 db) per octave. Which means when set at say 40 hz it starts to reduce the volume by 12 (or 24) db per octave. So by 20 hz (one octave down from 40 hz) the volume is 12 (or 24) db down. Obviously a 24 db slope is steeper than a 12 db slope.


Cheers
Gary

[jcisbig]

Nov 11, 2016 17:04:51 GMT -5 Gary Cook said:

The cross over is not a point, it's a slope, 12db (or 24 db) per octave. Which means when set at say 40 hz it starts to reduce the volume by 12 (or 24) db per octave. So by 20 hz (one octave down from 40 hz) the volume is 12 (or 24) db down. Obviously a 24 db slope is steeper than a 12 db slope.


Cheers
Gary

Sorry, I didn't explain very well. I understand the crossover frequency and resulting slope based on selecting either 24dB or 12dB slope. The issue is that with the crossover set at "X"hz and all the other speakers turned off, the roll off above the crossover point "x"hz looks EXACTLY the same regardless of whether 12 or 24 is selected. I should see a steeper roll off when 24 is selected and a shallower roll off when 12 is selected, but the roll off is identical when I measure in REW.

[bolle]

Which input signal did you give in and what slope are you referring to? There are 2 values, for the LFE and also for the crossover to the speakers, which affects speakers (highpass) and sub (lowpass).

To test the LFE slope you have to generate a .1 signal with RWE. To test the crossover slope you have to generate e.g. a FL or FR signal and use a mode like Stereo with the speakers disconnected.

I measured my old UMC-200 directly against a USB audio interface without speakers connected and the slopes work like they should.