These forums are read only, please use our new forums here.

Main :: StageScape M20d Mixer Community Support



FBS FeedBackSuppressor: some feedbacks will be suppressed, some not !!!
by Ruben40 on 2012-09-25 07:43:07

Hello

I tested the FBS system with a flat room mircrophone (dbx) and my home monitor speakers.

FBS was active and the eq was flat in the microphone channel.

To get the feedbacks I used the PEQ parametric eq with high q=10 and gain=15db in the main outs.

To avoid damage I used also a limiter in the main outs

I raised the microphon gain and started to adjust the frequency in the PEQ (Main-Outs) from 50Hz to 1kHz

At 110Hz I got the first room resonace feedback and after 1 second the FBS suppressed the feedback

There was also a red line in the microphone channel input frequency display. That was ok !!!

But the next feedback at 220Hz was not detected and the feedback tone sounded through the main outs.

I made several tests with my system(FBS Reset, changed to vocal algo,...). Result: Some frequences are suppressed, some are not.

In my opinion there must be a problem with the FBS algorythm, which should be solved in a future firmware update.

Maybe anybody else could make a similar test like mine?



Re: FBS FeedBackSuppressor: some feedbacks will be suppressed, some not !!!
by dboomer on 2012-09-25 17:11:59

The problem probably lies in the way you are generating the feedback.  When the system sees harmonics it concludes that is music.

Try it again with sine waves



Re: FBS FeedBackSuppressor: some feedbacks will be suppressed, some not !!!
by Ruben40 on 2012-09-25 23:05:27

Thanks for your answer

In my test I will produce feedbacks at certain frequencies.

These are "classical" feedbacks with a mic and a speaker and no music. These feedbacks should be suppressed.

I made more tests and I 've seen that a FBS reset suppresses the feedback frequency, that was not detected before. Why?

A second effect: When the feedback frequency rises again a second time than the red line of the FBS disapears and the feedback comes again.

How long will the FBS stay activ and when will it cancled ?

Please give us more informatíon how this FBS works.



Re: FBS FeedBackSuppressor: some feedbacks will be suppressed, some not !!!
by dboomer on 2012-09-26 09:31:52

The supressor has different settings that affect how the filters are set (wrt harmonics).  Have you tried switching to to a stronger setting?

It will catch mode feedbacks like this ... but it may also begin to catch some things you don't want it to.




The information above may not be current, and you should direct questions to the current forum or review the manual.