Forums :: Resources :: Features :: Photo Gallery :: Vintage Radio Shows :: Archives :: Books
Support This Site: Contributors :: Advertise


It is currently Nov Wed 14, 2018 6:40 pm


All times are UTC [ DST ]





Post New Topic Post Reply  [ 9 posts ] 
Author Message
 Post subject: P. A. system feedback
PostPosted: Feb Sun 04, 2018 3:04 pm 
Member

Joined: Nov Tue 11, 2014 7:03 pm
Posts: 37
I recently purchased a Rauland-borg model 4030 with a sure 575sb microphone. After fitting it with RCA jacks
Instead of 3-way jacks I hooked some old stereo speakers to it. The feedback-howl was terrible when I turned the volume up close to half-way. Turn the mike off and all is quiet. Is there anything I can do to help this condition? The only thing I can think of is that the mike is just too sensitive?
Respectfully yours,
Oldfarmer


Top
 Profile  
 
 Post subject: Re: P. A. system feedback
PostPosted: Feb Sun 04, 2018 5:32 pm 
Member

Joined: Dec Fri 08, 2017 5:40 pm
Posts: 147
Location: 44141
Sounds perfectly normal to me. Get the mic behind the speakers.

_________________
Bruce Hagen


Top
 Profile  
 
 Post subject: Re: P. A. system feedback
PostPosted: Feb Sun 04, 2018 6:11 pm 
Member

Joined: Nov Tue 11, 2014 7:03 pm
Posts: 37
Come to think of it I was pretty close to to the speakers.
Thanks, old farmer


Top
 Profile  
 
 Post subject: Re: P. A. system feedback
PostPosted: Feb Sun 04, 2018 7:06 pm 
Member
User avatar

Joined: Jul Tue 15, 2008 6:13 pm
Posts: 5385
Location: Gretna, Nebraska
Using a PA system in a room with lots of hard flat surfaces can also contribute to feedback.
Carpeted floors and fabric on the walls (like drapes) can help negate the acoustic reflections.

_________________
http://www.vintagerestorationservices.com
Paul
...... how hard can it be?


Top
 Profile  
 
 Post subject: Re: P. A. system feedback
PostPosted: Feb Sun 04, 2018 7:55 pm 
Member

Joined: Jan Thu 01, 1970 1:00 am
Posts: 17834
Location: Albuquerque, NM 87123
You can try connecting the woofers out of phase.


Top
 Profile  
 
 Post subject: Re: P. A. system feedback
PostPosted: Feb Wed 07, 2018 6:02 am 
Member

Joined: Feb Wed 17, 2016 2:38 pm
Posts: 176
Location: Cottage Grove, Minnesota
Pointing the element end of a microphone toward a speaker, at just about any listening volume, will cause feedback. The largest rejection of feedback is when the cord end of the mic is pointed towards the speaker. Most, but not all, feedback on a PA system is in the midrange.

If you have an EQ for/in the amp, start with it set completely flat, all controls at the midpoint. You want to attenuate the frequency that is feeding back. I find 1khz is a good place to start. A proper EQ job should have about half of the controls above the mid point and the other below. Attenuating all frequencies makes no sense as does boosting every frequency. You want to find a balance. Cutting the EQ in and out should not change the volume only the color.

As mentioned above a room greatly affects a PA system. Hard surfaces will reflect sound waves back to a mic and make trouble. An empty gymnasium without any sound deadening is probably the worst environment to run a PA. Fill that room up with people and your job just got easier. Better yet is a carpeted room with soft walls and ceiling, like a studio. Or the great outdoors, nothing sucks up sound waves like mother nature.

Running sound is both science and art. The tools available now make it much easier to sound good without nearly as much work as it used to be.

Have fun.

_________________
Andy


Top
 Profile  
 
 Post subject: Re: P. A. system feedback
PostPosted: Feb Wed 07, 2018 6:29 am 
Member

Joined: Jan Thu 01, 1970 1:00 am
Posts: 11883
Location: Mpls, Minnesota
A directional mic would also help.

Dave


Top
 Profile  
 
 Post subject: Re: P. A. system feedback
PostPosted: Feb Fri 09, 2018 12:20 am 
Member

Joined: Nov Fri 04, 2011 3:12 am
Posts: 905
Location: New York
If I recall, the 575 is a small Omnidirectional mic. So you definitely would have to have the speakers in front and pointed away in order to avoid feedback. At the very minimum you need to have this as far away from the speakers as practical.
John S.


Top
 Profile  
 
 Post subject: Re: P. A. system feedback
PostPosted: Feb Fri 09, 2018 2:14 am 
Member
User avatar

Joined: Jun Wed 08, 2011 2:33 am
Posts: 7355
Location: Ohio 45177
What exactly is your intention with the system? Because for PA use you definitely want a good directional microphone. That 575 looks like a mic for a consumer tape recorder, not PA use. If you need it for a public address application, I would invest in a quality directional mic, such as maybe a Shure SM58 at the high end, or something more economical but not dirt cheap. Dirt cheap will get you something that will probably break in the middle of some important function, or not really sound good or have ideal characteristics. So what are you thinking of doing? No point in fighting with trying to get the feedback minimized with that mic you have, if you are serious.


Top
 Profile  
 
Post New Topic Post Reply  [ 9 posts ]  Moderator: Alan Voorhees

All times are UTC [ DST ]


Who is online

Users browsing this forum: battery-maker, foglog, jrehkopf, Mike Toon, processhead, RadioNut39, Steve Chambers and 15 guests



Search for:
Jump to:  
























Privacy Policy :: Powered by phpBB