which plugin for feedback elimination

Hi!

As i use Ardour for adding FX to my analog IM8 console i ask you which plugin i could use for eliminating feedbacks from the mics.

i found this one:

but sadly not for linux / ardour.

So what do other users to eliminate feedbacks?

For manual use any parametric equalizer can be used. I am not aware of an automatic feedback eliminator which runs as a linux plugin.

A parametric eq is a good suggestion, a 1/3 octave graphic is another. The best is to ask why is the feedback happening in the first place and address that.

      Seablade

Many of these feedbacks are dependent on the acoustics of the room and the design of the microphones. Since I unfortunately can not always influence that would be an automatic solution a fine thing. Unfortunately not (yet) for Linux.

Many of these feedbacks are dependent on the acoustics of the room and the design of the microphones. Since I unfortunately can not always influence that would be an automatic solution a fine thing. Unfortunately not (yet) for Linux.

If you are having feedback due to acoustic issues in the room, look at your speaker and mic placements, then use a parametric or 1/3 octave graphic to notch those frequencies. If it is the design of the microphones, as above first look at your mic placements, and your mic choices (Using all omni mics for instance is typically a poor choice for live reinforcement, musical theater not withstanding).

Automatic feedback eliminators can do as much damage as good honestly, and very rarely are they worth it. While they can certainly notch feedback, doing so without first addressing other issues like mic/speaker placement can mean you are notching frequencies unnecessarily, and destroy the sound as a result. Even worse in ‘automatic’ mode many of these feedback eliminators will eliminate frequencies that are not actually feedback, again quickly destroying your sound. For instance a flute is a fairly pure tone instrument, playing one through a feedback eliminator will often notch the fundamental of the note being played, not only severely lowering the volume of the flute being reinforced, but also any other instrument that plays that note. This is just the simple example, it isn’t only pure tone instruments they notch. There is a very good reason that you won’t find ‘automatic’ feedback eliminators in many professional systems, if you learn the concepts below you get better results without them.

I would highly suggest looking at your speaker and mic placement first, then learn to tune the system for flat response using EQ (and delay as appropriate) on the outputs, and finally in your last step learn to notch a frequencies using a parametric eq (A starting sweep and kill technique is not difficult to master). More than a few frequencies notched typically means your system wasn’t tuned/placed right to start with.

       Seablade <-- teaches live sound reinforcement and system design

@Seablade

You have convinced me.
In the future I will deal with my PA in different environments and try to find a certain routine for myself.
So far I have not been able to find the time for it.
I do not do this professionally but only look after my own band.
The biggest problem is the rehearsal room, because it has a sloping roof where the monitors shine back exactly onto the microphones.
Which microphones (currently SM58) would you recommend to keep the feedback generally lower? I read that the SM58 are very vulnerable here.

As this is a rehearsal space, maybe just having people turn sideways… or at least the mics. There is nothing really wrong with sm58, they have reasonable patterns and sound, which is why they are used so widely, unless you want to buy all shotguns. If they are being used on stands, try setting them sideways to the performer or raising them a bit so they can be pointed down (in rehearsal it doesn’t matter if the mic hides the face so much). Reversing polarity on one or two mics (or the monitors) may have an effect as well. Basically you are going to have to get creative and experiment. It may take a different idea for each mic. If used handheld, first don’t cup the mic, hold it as far away from the head as possible. If you have a lead singer that uses mic cupping as an effect, you will need to try moving your lead singer, adding a portable sound shield whatever. If you are able to attach things to the walls of the space, a frame over the sloped roof part with cloth on the front filled with insulation batts could be done for not to much money too. One other possibility is inear monitoring…

BTW the idea of using shotgun mics was not meant to be serious…

The biggest problem is the rehearsal room, because it has a sloping roof where the monitors shine back exactly onto the microphones.

If it is a rehearsal room, think a bit outside the box, can you raise you speakers up on sticks like you would your mains so they don’t hit that sloped roof?

SM58 isn’t bad, there are better, the OM7 for instance is known for good feedback rejection, however you have to be very good about mic technique on that mic as well, keep that in mind.

    Seablade
If you have a lead singer that uses mic cupping....

Don’t.

Cupping your mic will destroy the pattern control of the mic, and make it far more likely to feedback. Counterintuitive, but trust me, cupping the back of the mic actually lets it pick up more to the rear(Really all directions as it turns it into much closer of an omni mic). If you are having feedback issues this is the first thing I would look at changing.

       Seablade

@seablade: Do you have any material (youtube vids, pdfs, etc,…) on this subject of tuning live PA systems?

I don’t off hand. I used to use a series of essays by Jason Pritchard on the topic for reading materials for my students called ‘Assorted Essays on Audio’. One of them was called ‘You can tuna fish but can you tune a sound system?’ that is decent reading material on the topic.

I will have to look for videos on the topic to see if I can find any. Eventually I want to create a series of videos but need time and/or money in order to do so:) Some topics such as proper delay on the system etc. is tough to show on video to be honest, which is why doing hands on lessons to demonstrate with my students works decent, but you could cover the basics of EQ on the system etc. through video decently I think.

Often these days software such as Smaart is used in the process for larger systems, however it is entirely possible for many smaller systems to tune effectively by ear as well, so even if you see references to Smaart, don’t feel like you need more tools.

           Seablade