feedback issues

[KGreene]

I'm pretty much a rookie when it comes to sound systems and I've recently purchased a Yamaha EMX7 and a pair of Yamaha BR15's. I'm using an MXL 990 and a pair of MXL 993's ... I also have a Rode NT1 and a matched pair of Rode NT5's. I can't seem to get very much volume at all with either of the mic sets before getting feed back ... could the fact that they're all condenser mics be the issue?

Any insight would be appreciated.

[mandroid]

Stage craft...

move stuff around, ..placing speakers in the null spot of microphones is cost free..
mics hear them selves in speakers.. thats the feed back loop

[almeriastrings]

Many factors contribute to feedback. Gain levels... the room (reflections), speaker positions relative to the mics pickup pattern, etc. There is also the need to EQ both sources (and often) the main outs. Some background reading:

http://blog.shure.com/how-to-control...-sound-system/

https://www.soundonsound.com/sound-a...event-feedback

[rcc56]

Microphones must be placed behind the speakers. Pointing speakers at an angle instead of straight at the opposite wall can be helpful. Condenser mics are great when you're in a good room. They must be EQ'd. I notice that the current EMX7 no longer has a built-in graphic equalizer. When you're in a not so good room, SM 57's and 58's are easier to control. Try turning your effects off and see if that helps.

[TonyP]

It also says it has a " feedback suppressor", is it on? I guess they added that instead of the graphic eq.

[Strad]

I do sound for our 5 piece bluegrass band and have used the 990, with that being said when your using a big condenser always start with the mids at about 9 o'clock and the lows at about 11 on that channel. Always start with the mains at about 2 or 3, and bring each mic channel up as needed. This give you much more control of the feedback issues. When I have feedback issues it's usually the mids. Also set it up for a practice with the band, and dedicate that practice to getting the sound figured out. Oh and keep all the effects knobs off until you get the other stuff figured out.

[KGreene]

Many thanks to all ... It very well may be a stage craft issue as the past few venues have not been the best for sound (especially for condensers... very loud patrons). Yes the "feedback suppressor" was on, but due to the areas available the mains were basically parallel with the mic positions. I suppose I need to start with the positioning of the components and go from there if its doesn't cure the issue. I also have an older non-powered Beringer mixer, would this (or something similar) aid in equalizing? (assuming the positioning and gain levels doesn't solve the issue).

Thanks again for the "feed back" ... it's very much appreciated.

[Strad]

I would try just what I said in my post, I get more volume with condensers than dynamic mics. You need to mess with the mids on that 990 channel. You also should dedicate a practice with the whole band just to get the mixer figured out. Keep us posted on how your making out with it.

[Strad]

Also back that bass roll off back on the 933s that will cause feedback also.

[MontanaMatt]

Next time you hear your feedback rolling, hit the phase button. Sometimes that's the easy fix.
Plus, learn the art of sound engineering. It takes a lot of practice, but is worth the effort if you perform and run your own sound.

[Beanzy]

Here’s a shot of the pickup pattern for your 990 mic. Try to get the speakers in a line with the least sensitive part of the pattern. You can see it’s not a very wide spread to work with.


I managed to find a polar pattern for the 993s, which isn’t what I was expecting. They’re quite broad pick up in front, without much of a node out back. You might need to have these pointing directly towards the back of stage and avoid angling them so the side pickup area isn’t turned out towards the front.

[TonyP]

I could be wrong, but I don't see much of a gain with the Berhinger mixer, pun intended. A lot of times stage craft is a wish more than any possible reality. Most places around here are just barely big enough for a duo, much less a quartet with PA. Smashed in a corner with a window to your back with a young crowd more interested in drowning you out no matter how loud you get is the norm. So for those gigs a set of dynamic mic's and a good feedback buster (I like dbx)helped but there was still a wall where we couldn't compete. I was going to suggest a dbx go rack but they have discontinued it. Seemed like a good unit and they want triple on eBay than they were selling for new.

[Steve Ostrander]

Most places around here are just barely big enough for a duo, much less a quartet with PA. Smashed in a corner with a window to your back with a young crowd more interested in drowning you out no matter how loud you get is the norm.

We must be playing the same venues. . .

[lflngpicker]

Is there a ground lift button? That will often deal with the issue immediately. Also, it is good to set it up at home before heading to a gig with intentionally mixing things to feed back and then dial the mid range frequency out to prevent that blast of sound. The other thing is to have a preamp DI box which allows you to select the mid frequency range in addition to the EQ level itself. I am very poor at electronics, but as an entertainer, I have had to learn to respond. The mic and speaker placement discussion above was very well stated, too. Just my two cents-- YMMV.

[pops1]

Since every room is different I always advise to set the PA up at home, or preferably in a larger space. Then turn it up until if feeds back. Play with the EQ sliders and listen to what slider controls what frequency, so when you are out you know where to go. Turn all the knobs lots and get familiar with them. Most rooms are heavy in the 250 +- area and I usually lower that and it really cleans up the sound and helps eliminate muddy sound.

[Mandoplumb]

Pops is the first one to mention the room and that is the key to the problem. If it was certain freq. that caused the problem mic makers would build in means to cut those. True certain mics may have "hot spots" that need to be pulled back but to set up a P.A. correctly the room must be rung out and each room or hall is different. Feedback busters seem to do a reasonable job but given the time before the show I prefer to do my own.

[KGreene]

Many thanks to all ... We're free this Friday (for a change) so I'll set it up in the garage as well as outside on the pavilion and play with the positioning in relation to the 990 and 993 patterns the mids and bass (on the 993's). I'll post some before and after results if they seem to be significant.

Mandoplumb - What part of the state are you in? ... I'm fairly central (Orange County).

[pops1]

Remember the room changes from before the show when it may be empty to when the show is in full swing and there are lots of people. That's why I like to be familiar with the frequency of feedback so I know where to adjust and do it quickly. For me it is hard to concentrate on playing as long as the sound is funky. Once it is dialed in I can forget it and have fun. Quicker I can do that the more fun I can have. Outside you will seldom have problems as there is nothing to reflect the sound back to the mic. I love playing outside.

[almeriastrings]

Pops is the first one to mention the room and that is the key to the problem.

See post 3....

[Mandoplumb]

KGreene I am live in the Roanoke area. I'm pretty much old school with sound equip. but glad to help any way I can PM me if you think I can help. Almeriastrings sorry I had read your post and agree with your points, just had a senior moment as I posted.

[TonyP]

For the record we started out with a very similar unit. And struggled with feedback constantly. Since it was owned by another member when I went to another band that had no PA I decided to take it on. I knew the pitfalls of powered head PA's for what I wanted to achieve. I was trying for a modified single mic setup a lot like the OP. I started with powered speakers and an old 12ch Alesis rack mount mixer with a dual 31 band eq. I used a early version of a pro audio analysis program on my lap top that showed me exactly which sliders on the EQ to adjust. It worked but using a 31 band eq for feedback is a little like doing dentistry with a sledge hammer.
It is not precise and takes some of the audio signal with it. A parametric eq is better but each one of these units takes more skill to use and you are still faced with the fact things change with crowds and humidity like when the sun goes down. So all that fancy torture you subjected the early birds to goes right out the window in my experience. I got a dbx 260 DriveRack and that really upped the game and could also automatically stop feedback when things changed and took out the feedback even more surgically than a parametric eq. I still had to torture the early birds but it was pretty quick. Then I got a line6 digital mixer that has anti feedback built in to each channel and no more torture, no more mucking about because we never have the luxury to take our time to setup. Just plug in and go. Every once in a while you'll hear something start but the black box catches it and we're good to go before anybody even hears a problem. There is tech that works and for me it was worth it.

[MontanaMatt]

We use the mackie dl1608, and it has a spectral analyses, which makes feedback easier to deal with.