You are here

Whistling sound from speakers with High EQ

For performing musicians and engineers: stagecraft, engineering and gear.

Whistling sound from speakers with High EQ

Postby Guest » Thu Aug 08, 2019 10:07 am

Hi
I have ran a couple of behringer mixers with the High EQ turned up to full, and when I turn it up on bough mixers I get a whistling noise from the speakers. Any ideas on how to avoid please?
Guest

Re: Whistling sound from speakers with High EQ

Postby Hugh Robjohns » Thu Aug 08, 2019 10:10 am

Don't turn the high-EQ up full... simples! :lol:

A flippant answer, perhaps, but frankly you haven't given anything like enough information for anyone to be able to offer any kind of sensible answer.

For starters, is this 'whistle' apparent when you have a live source faded up on the desk -- if so, what is the source? Are we talking open microphones here? Could you be describing a high-frequency acoustic howlround?

Or is the source generating some high frequency noise itself which you are then raising to audibility?

Or is this unwanted whistle there even when all the desk faders are closed?

If the latter, then we need to know how the speakers are wired into the desk. Balanced or unbalanced. Are the speakers and desk running from the same mains outlet, or different outlets? What else is connected to the desk?

Give us a clue....
User avatar
Hugh Robjohns
Moderator
Posts: 24569
Joined: Fri Jul 25, 2003 12:00 am
Location: Worcestershire, UK
Technical Editor, Sound On Sound

Re: Whistling sound from speakers with High EQ

Postby Arpangel » Thu Aug 08, 2019 10:33 am

What Behringer speakers have you got? I use a pair pair of 3031A now and again, I turned up the high EQ switch, no whistling sound. This may be an input/source issue, turn down or unplug your sources and see if it goes away. But this just may be a case of variable "Behringer build quallity" in which case, take Hugh's advice!
User avatar
Arpangel
Frequent Poster
Posts: 1477
Joined: Sat Jul 12, 2003 12:00 am

Re: Whistling sound from speakers with High EQ

Postby Guest » Thu Aug 08, 2019 2:06 pm

Hugh Robjohns wrote:
For starters, is this 'whistle' apparent when you have a live source faded up on the desk -- if so, what is the source? Are we talking open microphones here? Could you be describing a high-frequency acoustic howlround?

Or is the source generating some high frequency noise itself which you are then raising to audibility?

Or is this unwanted whistle there even when all the desk faders are closed?


.
I don't know, will have to go and test and report back, but the closer the microphone is too the speakers (s) the greater chance or a whistle or the louder the volume is set on the speakers the greater chance

But some sound tech guy advised that I needed more High EQ and less Low EQ on my voice
Guest

Re: Whistling sound from speakers with High EQ

Postby Hugh Robjohns » Thu Aug 08, 2019 2:36 pm

night ans day wrote:...the closer the microphone is too the speakers (s) the greater chance or a whistle or the louder the volume is set on the speakers the greater chance...

Ah yes. I think the professionals call that a HOWL-ROUND. It happens when the overall gain in the system exceeds unity and so leads to positive feedback. Sound from speaker gets into mic. Signal is amplified and routed back to speaker... and so on.

The only way to prevent it is to reduce the amount of sound from the speaker getting in to the mic!

You can do that in many ways, and normally you will require a combination of them.

Maximise the distance between speakers and the mic.

Optimise the directionality of the speakers and mic to minimise pickup -- which usually means placing the speakers closer to the audience than the mic (so the mic is behind the speakers) , and use a directional mic with its least sensitive sides facing the speakers.

Choose or adjust the PA system and mics to have as flat a frequency response as possible -- howl-rounds occur first at the response peaks.

ALWAYS use EQ cuts rather than boosts .

But some sound tech guy advised that I needed more High EQ and less Low EQ on my voice

Try cutting the bass rather than boosting the HF! Try a different mic. Improve your mic technique. Optimise the setup of speakers on stage relative to the mic... etc...
User avatar
Hugh Robjohns
Moderator
Posts: 24569
Joined: Fri Jul 25, 2003 12:00 am
Location: Worcestershire, UK
Technical Editor, Sound On Sound

Re: Whistling sound from speakers with High EQ

Postby Guest » Thu Aug 08, 2019 3:50 pm

Hugh Robjohns wrote:Ah yes. I think the professionals call that a HOWL-ROUND. It happens when the overall gain in the system exceeds unity and so leads to positive feedback. Sound from speaker gets into mic. Signal is amplified and routed back to speaker... and so on.
will turning the gain knob down not help?
Guest

Re: Whistling sound from speakers with High EQ

Postby Hugh Robjohns » Thu Aug 08, 2019 3:56 pm

Yes... and so would not turning up (so far) the HF boost gain knob!
User avatar
Hugh Robjohns
Moderator
Posts: 24569
Joined: Fri Jul 25, 2003 12:00 am
Location: Worcestershire, UK
Technical Editor, Sound On Sound

Re: Whistling sound from speakers with High EQ

Postby Mike Stranks » Thu Aug 08, 2019 4:51 pm

I found that most feedback problems can be sorted by adjusting the EQ, rather than dialling back the gain. More effective as you're only attenuating the offending frequencies rather than those and everything else too.
Mike Stranks
Jedi Poster
Posts: 6925
Joined: Fri Jan 03, 2003 1:00 am

Re: Whistling sound from speakers with High EQ

Postby AlecSp » Thu Aug 08, 2019 5:45 pm

Wonder what sized cones they are...? ;) </twitch>
AlecSp
Regular
Posts: 391
Joined: Tue Nov 16, 2004 1:00 am

Re: Whistling sound from speakers with High EQ

Postby Guest » Thu Aug 08, 2019 6:41 pm

Take a listen to this at 32 seconds you hear ooh ooh ooh ohh ooh ooh, was not sure if it was to much falsetto in my voice or the mixer set up wrong

This was a home recording with no PA speakers present, for the mic channel the High EQ turned up to full and the Low EQ turned to minimum. And the gain and the level bough set to 5/8 turned on

https://www.dropbox.com/s/upxy6m6d83cdv ... o.m4a?dl=0
Guest

Re: Whistling sound from speakers with High EQ

Postby Sam Spoons » Fri Aug 09, 2019 6:45 am

Those peaks are distorting, I can't hear any whistling on my laptop speakers.
User avatar
Sam Spoons
Jedi Poster
Posts: 10191
Joined: Thu Jan 23, 2003 1:00 am
Location: Manchester UK
Finally taking this recording lark seriously (and recording my Gypsy Jazz CD)........

Re: Whistling sound from speakers with High EQ

Postby Guest » Fri Aug 09, 2019 9:58 am

Sam Spoons wrote:Those peaks are distorting, I can't hear any whistling on my laptop speakers.
what do you thinks causing it then?
Guest

Re: Whistling sound from speakers with High EQ

Postby Mike Stranks » Fri Aug 09, 2019 10:36 am

Sam Spoons wrote:Those peaks are distorting, I can't hear any whistling on my laptop speakers.

Yup! Listened on decent monitors in my treated room. No 'whistling', but excessive presence in the vocal causing various artefacts.... but then there would be wouldn't there?
Mike Stranks
Jedi Poster
Posts: 6925
Joined: Fri Jan 03, 2003 1:00 am

Re: Whistling sound from speakers with High EQ

Postby Guest » Fri Aug 09, 2019 10:46 am

Mike Stranks wrote: but excessive presence in the vocal causing various artefacts....
Are you saying I am a little loud and should back off the mic then?
Guest

Re: Whistling sound from speakers with High EQ

Postby Hugh Robjohns » Fri Aug 09, 2019 10:59 am

Dialling in maximum boost adds 16-18dB of extra level at high frequencies, and that could very easily result in overloading the mixer's mix bus. If you're going to dial in that much EQ you will probably have to back of the input gain a bit to compensate and maintain headroom in the mixer.

So it's more about setting up a sensible gain structure than backing off the mic.

But as I and others have already said, adding that much HF boost is not ideal, especially in a live-sound situation.

Cutting unwanted frequencies is always better than boosting the wanted ones!
User avatar
Hugh Robjohns
Moderator
Posts: 24569
Joined: Fri Jul 25, 2003 12:00 am
Location: Worcestershire, UK
Technical Editor, Sound On Sound

Re: Whistling sound from speakers with High EQ

Postby Guest » Fri Aug 09, 2019 11:15 am

For that recording you heard the High EQ was set to max and the level and gain set to 5/8. I'll try an experiment this afternoon (after my morning voice has wormed up) by recording the same chord playing around with all 3 knobs to see if there is any improvment
Guest

Re: Whistling sound from speakers with High EQ

Postby Guest » Fri Aug 09, 2019 7:05 pm

I just tried it again as set as before and there is no distortion this time so I don't know.

But as a general rule should the gain and level be set even and set to the middle, and the high EQ set to the middle too?
Guest

Re: Whistling sound from speakers with High EQ

Postby Sam Spoons » Fri Aug 09, 2019 9:52 pm

No, not really, the gain needs to be set to suit the source at each stage of the signal path, it is adjustable at the preamp and via the eq and, sometimes, further down the chain. The crucial thing is to ensure that it is not overloading at any point in the signal path. WRT to mic technique, backing off the mic when 'belting' is standard practice.
User avatar
Sam Spoons
Jedi Poster
Posts: 10191
Joined: Thu Jan 23, 2003 1:00 am
Location: Manchester UK
Finally taking this recording lark seriously (and recording my Gypsy Jazz CD)........

Re: Whistling sound from speakers with High EQ

Postby Guest » Sat Aug 10, 2019 11:14 am

Sam Spoons wrote:No, not really, the gain needs to be set to suit the source at each stage of the signal path,
The crucial thing is to ensure that it is not overloading at any point in the signal path.
Is there a proper way to do a diagnostic test with say a multi meter or something?
Guest

Re: Whistling sound from speakers with High EQ

Postby Hugh Robjohns » Sat Aug 10, 2019 11:35 am

night ans day wrote:Is there a proper way to do a diagnostic test...

Yes!

...with say a multi meter or something?

No!

The correct procedure is to use the PFL (or solo) button on each channel which will display on the meter the signal level as it reaches the channel fader. You can then adjust the input gain to optimise the signal level -- usually so that it averages around the zero mark on the meter.

Do yourself a favour and read a decent book about the practical side of live-sound production. This one's not bad...

https://www.soundonsound.com/shop/books/sos-guide-live-sound
User avatar
Hugh Robjohns
Moderator
Posts: 24569
Joined: Fri Jul 25, 2003 12:00 am
Location: Worcestershire, UK
Technical Editor, Sound On Sound

Next

Who is online

Users browsing this forum: Sam Spoons