Wierd monitor feedback...Any thoughts?

[BFSound]

So i have been doing some work to our monitor system at our practice spot and ( messing around with speaker placement etc...). So our singer uses a sennheiser E835 i believe i have yet to find out but its either that or the E865 which is a super, i think his is the cardioid though. Any way i placed it at his singing level in front of his three monitors. And started to ring out the center mix. Which went awesome only a few freq. had to be rung out . Then i proceeded to to outer two monitors which is his second mix and at about the same level as the center mix it begins a slight high pitch feedback then increases really quick to a goose honk/ Humm sound. And my EQ doesnt show any frequencies feeding back? What could this be i have all the monitors placed in the mic null ? center mix dead center and outer two at a slight degree facing inward.

Thanks, any thoughts would help greatly.

[AlexK]

The feeding-back sound doesn't have to enter the mic directly from the speakers, it can be a reflected sound.

There could be a million and one things causing it, just simply find out which frequency it is and notch down until you get enough GBF...

[ears2thesky]

Supercardiod is going to affect the outside wedges. Cardiod is going to affect the center mix.
I wonder why the vocalist needs three wedges to hear him/herself. I would probably lose the center, and use the two sides slightly angled in to match the cancellation points of the mic. Experiment with the placement of the boxes--not just the EQ. BTW the high-end "squeaker" frequency is usually right around 6.3k
I've noticed compression inserted into the vocal channel often results in more feedback problems. Unless it's absolutely necessary I don't compress the vocal channel. I insert a compressor on a subgroup, run the vocal through the subgroup (well squashed) in addition to busing the vocal straight to the mains(uncompressed and feeding the monitor mix). I then bring it up parallel to the vocal channel, and push it when I need more gas on the vocal in the mains.

[BFSound]

I bus compress for FOH and don't compress for monitors. He needs three wedges because be practice in a 30' by 15' room with high celings. And all the walls are covered in sound canceling material so the room has good acoustics and with FOH and drums right behind him it gets loud. Guitars are very quite yada yada yada. I guess i would have to maybe get a sound bit recorded so you can hear its a wierd honkie burst of noise not really feedback. I guess i have to figure if he using a super or not first to get my placement right. Also i thought supers null was around 180 and 180 picking up directly in front and to the rear to supers would be affected by center and vis versa for cardiod. cardiod blocks directly behind and to about 175 degrees or so. I would have to check his mics polar pattern to be exact.

[plexisys]

with FOH and drums right behind him

Why would the FOH be behind him?

[BFSound]

Its not? Maybe i should insert a comma... But its called FOH for a reason its, usually its in front, lol. Typo i guess. What i mean is with drums about 8' behind him and FOH out FRONT , And a room that gets loud very easy. Even with guits turned down he has a hard time hearing. Im currently working on suspending some noise canceling panels around the drums to help. But until then it get loud no matter what!

[mixedupsteve]

Originally Posted by BFSound

Its not? Maybe i should insert a comma... But its called FOH for a reason its, usually its in front, lol. Typo i guess. What i mean is with drums about 8' behind him and FOH out FRONT , And a room that gets loud very easy. Even with guits turned down he has a hard time hearing. Im currently working on suspending some noise canceling panels around the drums to help. But until then it get loud no matter what!

If it's too loud then you need to turn it down or fewer monitors. Maybe move the drums or build screens around them. If it's a practice space you don't even need FOH anyway.

[BFSound]

FOH is not needed no. But its there for the people like me, girlfriends, friends, kids, sponsors, managers, who come and watch practice. And now that i think of it generally FOH can not really be heard on stage to much, i actually just had this conversation about the difference in volume between the stage and FOH the other day. I really honestly think its just drums. What kind of screens are you talking about. Could i just hand heavy moving blankets around the kit, i want him to see still. Toms and cymbals really carry the most i generally dont even turn them on in FOH they are so loud!

[BFSound]

Here are the polar patterns for the E835 cardioid and the E865 super-cardioid.

First JPG = E835

Second JPG = E865

Based on the patterns for the cardioid 180, 150, and 150 would be the ideal placement, correct?

And for the E865 135 and 135ish. having no center speaker.

[ears2thesky]

Looking at that response plot I would say the most cancellation for the E865 is right between 120 and 150.
Ideally rehearsal is used to make the stage/studio performance better. The closer you can come to approximating real-world conditions for either of these objectives the more productive the time spent can be. Many bands set up a combination of equipment that does not prepare them for a gig. The PA will be at the proscenium and wedges will be firing back at the performers upstage of that line.
I have seen bands spend lots of money on PA equipment when what would be a better investment would be a monitor system. Having your own mics (possibly premounted to the gear) allows production continuity and quicker setup/breakdown.

[mixedupsteve]

Some plexi screens/gobos should work great. I still don't understand why 3 monitors. Are you saying that you cant achieve the SPL you need unless you use three or what. What kind of monitors and amps are they and how are they wired up?
The 865 is a condenser and while I don't have any experience with that exact mic I personally don't like condensers on loud stages.

[mixedupsteve]

One more thing. Consider an IEM rig.

[BFSound]

Originally Posted by ears2thesky

Looking at that response plot I would say the most cancellation for the E865 is right between 120 and 150.
Ideally rehearsal is used to make the stage/studio performance better. The closer you can come to approximating real-world conditions for either of these objectives the more productive the time spent can be. Many bands set up a combination of equipment that does not prepare them for a gig. The PA will be at the proscenium and wedges will be firing back at the performers upstage of that line.
I have seen bands spend lots of money on PA equipment when what would be a better investment would be a monitor system. Having your own mics (possibly premounted to the gear) allows production continuity and quicker setup/breakdown.

As for the gear set up, we use our gear like we would at a show, which stays set up week to week unless we have a show which i then break down and load all band equipment. Which i then re-set up fully the next day or so for our weekly jam. (PA stays obviously unless we sometime bring monitors or sidefill) Most of the PA gear has been aquired from my father who is an engineer who collected the stuff, Some free. And some bought. Maybe 10k invested.

[BFSound]

Originally Posted by mixedupsteve

Some plexi screens/gobos should work great. I still don't understand why 3 monitors. Are you saying that you cant achieve the SPL you need unless you use three or what. What kind of monitors and amps are they and how are they wired up?
The 865 is a condenser and while I don't have any experience with that exact mic I personally don't like condensers on loud stages.

Yea thats what my old man said, they had a full plexi drum surround kit at guit center for like $250. The reason for three monitors was just simply to try a different method. By having three i can run vocals through the middle wedge and other mixes through the outer two. Im thinking heis using the 835 cardioid so i might try eliminating the middle wedge and go back to two and just get the placement right. The mixes are setup like so. there are 6 mixes. Each aux send goes through my snake return to an amp channel to the speaker. The amps are set up stereo each channel is its own mix. I will get the speaker model number tomorrow at practice i honestly dont remember. I know its good to use all the same wedges even cue wedge but we just cant invest in all the same right now so i try to keep as many as possible the same.

As for an IEM. Im assuming that In Ear mobile. Well to start with being in the studio etc... and getting ready to make CD's they wont want to spend that money. 2nd they are old school and like monitors and dont like to look or feel of In ear. Our lead vox cannot have them he would destroy them with his stage performance and most often wears no shirt and wont want wires dangling.

[BFSound]

Also there are EQ's in the chain as well. currently in line. Tomorrow im picking up as mint yamaha mc1608 to run all mixes from 1 board designed for monitors. I know its older and very simple. But its a steal and what were looking for plus like i said its simple and effective. So that said i will be now able to hook up EQ's via insert. And have a cue wedge so i can hear what im mixing.