Automatic Feedback Destroyer, new vs old generatoin comparison

[[email protected]]

I own and have hands on experience using the old Shure DFR11EQ.

It works well enough as an auomtatic tuning notch filter if you
set it up BEFORE a show and let it "hear" some feedback so it can set up the filters. Basically it's an easier way to "ring out" a system

But as far as recognizng feedback on the fly during a show, it is much slower to react to feedback on the fly than I can do by hand on a fader.

Also it cannot in any way anticipate feedback before the fact and set a filter before the feedback actually happens.

I had hoped that some DSP magic could actually anticipate feedback before the fact and set a notch filter before audible feedback. I can image such a feature might be very difficult to accomplish but perhaps tis possible. There are some clever DSP folks out there. Can the new generation devices anticipate feedback and react or do they all work basically the same as the DFR11 I already have?

thanks

Mark

[Mike Rivers[_2_]]

On 2/15/2016 10:59 AM, wrote:
> I had hoped that some DSP magic could actually anticipate feedback
> before the fact and set a notch filter before audible feedback. I
> can image such a feature might be very difficult to accomplish but
> perhaps tis possible. There are some clever DSP folks out there.
> Can the new generation devices anticipate feedback and react or do
> they all work basically the same as the DFR11 I already have?

The problem is that there's nothing to recognize until it's too late. In
theory, you could compare the spectrum of the input to the speakers to
the spectrum of the sound in the room, normalize out the room, and
what's different is ringing. The only problem is that as soon as there's
ringing at the output, it's at the input, too, so in comparison, they'd
be the same so the clever DSP folks wouldn't find anything wrong.



--
For a good time, visit http://mikeriversaudio.wordpress.com

[[email protected]]

On Monday, February 15, 2016 at 3:05:06 PM UTC-5, Mike Rivers wrote:
> On 2/15/2016 10:59 AM, wrote:
> > I had hoped that some DSP magic could actually anticipate feedback
> > before the fact and set a notch filter before audible feedback. I
> > can image such a feature might be very difficult to accomplish but
> > perhaps tis possible. There are some clever DSP folks out there.
> > Can the new generation devices anticipate feedback and react or do
> > they all work basically the same as the DFR11 I already have?
>
> The problem is that there's nothing to recognize until it's too late. In
> theory, you could compare the spectrum of the input to the speakers to
> the spectrum of the sound in the room, normalize out the room, and
> what's different is ringing. The only problem is that as soon as there's
> ringing at the output, it's at the input, too, so in comparison, they'd
> be the same so the clever DSP folks wouldn't find anything wrong.
>
>
>


yes, theoreticaly there are DSP ways to tell if a system is about to go into feedback but they are very complicted and probably not workable in a live room with actual program material ......

I am perfectly happy with the DFR11 as far as operation and transpareny, I just wish it was smarter/faster at recognizing feedback, which as we have been discussing, is not easy (for a machine).

From a practical perspective, I wanted to know if there was any reason to buy a newer device, but it seems the DFR11EQ I already have is about as good as they get.

thanks
Mark

[Mike Rivers[_2_]]

On 2/16/2016 8:35 AM, wrote:
> I am perfectly happy with the DFR11 as far as operation and
> transpareny, I just wish it was smarter/faster at recognizing
> feedback, which as we have been discussing, is not easy (for a
> machine).
>
> From a practical perspective, I wanted to know if there was any
> reason to buy a newer device, but it seems the DFR11EQ I already
> have is about as good as they get.

At some point, you need to accept that there are physical reasons for
feedback, and eliminate as many of them as you can. Choose a different
microphone, move a loudspeaker, tell a singer how to hold a cardioid
microphone so it doesn't turn into an omni and lose its distance
advantage or not to dance in this or that area. Keep the monitor level
sane or put the band on in-ear monitors, and work on a good pickup
system for acoustic instruments that rejects stage sound.

Admittedly, in most of the live sound situations that I mix (community
or regional folk festivals), there really isn't anything I can do about
any of that. Many of the performers are inexperienced when it comes to
working with sound systems, there are no sound checks, and usually you
only see the performers once during a day or weekend so you can't tell
them next time to do something differently.

--
For a good time, visit http://mikeriversaudio.wordpress.com

[Scott Dorsey]

In article >, Mike Rivers > wrote:
>
>Admittedly, in most of the live sound situations that I mix (community
>or regional folk festivals), there really isn't anything I can do about
>any of that. Many of the performers are inexperienced when it comes to
>working with sound systems, there are no sound checks, and usually you
>only see the performers once during a day or weekend so you can't tell
>them next time to do something differently.

You can jump up and down waving your hands and pointing at your mouth to try
and urge the performer to point the handheld microphone at their mouth instead
of their navel.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

[None]

"Scott Dorsey" > wrote in message
...
> You can jump up and down waving your hands and pointing at your
> mouth

... and nobody will know why, unless you have explained to them in
advance what it means when you jump up and down pointing at your
mouth. It's always a crap-shoot when you try to tell a singer how to
hold a microphone.