Seth wrote: ↑Thu Oct 07, 2021 10:22 am
Tall Evan's post in Grey Owl's thread reminded me of a "problem" I had experienced while mixing live a couple times. I just did a search on it, but didn't turn up any relevant results.
During indoor rehearsals, no issue. But, live outdoors with full PA at show volume, the bassist (standard hardbody 4 string electric bass, flat wound strings) and rhythm guitar (deep body acoustic 12 string Ovation) had to mute their strings between songs to keep them from... I don't know... auto-exciting? I assume it's a form of feedback. The first time it occurred, it caught us all off guard. I've read about acoustic guitars and acoustic bass guitars feeding back and possible solutions for the Ovation. But, haven't been able to find anything on hardbody bass.
In the two or three times it's occurred, the bassist was less than 6 feet from the subs with no option to put more space between them. Signal was DI'd from an out on his amp.
Is this something you guys have dealt with? Is there anything I can do on my end, as the sound guy, to eliminate or reduce the condition? Or, is it just a thing I've got to remind the guys of before going live?
I've definitely experienced this before. More times than not, it's the A string/Note that caused it. You didn't say if you had bass and acoustic coming through the monitors - I'm assuming you did for the acoustic. The root cause is EQ. Every time you mix, you should:
High pass every channel - period! Even bass and kick. I typically high pass those at 40 or even higher if inside. Acoustic guitar - get it way up there......minimum 100hz up to 200hz if it needs it.
High pass the monitor sends every time. If there is a bass amp on stage, then nobody needs much bottom end in the monitors - high pass 'em between 80-100hz.
EQ your mains properly - have a couple of test songs that you know well. Listen carefully to the bottom end to make sure is isn't muddy. And some bottom-heavy grunge stuff is not what you want to test with. Use something that really lets you hear the bottom end and pick out the nasties.....
If all that is done properly, you will most likely have no problems....but, if it does - get the bass player to help you identify what note is causing the problem, then notch that frequency with a parametric EQ on the channel and/or monitor and/or mains until it goes away.
Occasionally, it will happen in the middle of a show and it's intermittent. On bass is still easier to find by watching his hands to see what note is causing the problem. On acoustic, it's harder. But, if your mixer has RTA built in, try to find it by watching for spikes.
Now, if this is just a problem with the acoustic guitar player taking his hands off the strings and it starts to feedback - then try moving the monitor and more of an angle to the guitar, turn down, high pass channel and monitor sends.
Earlier this year, I mixed a gig at an outdoor venue that I've mixed many times. Sound check went great, everything was fine. Started the show and the lead singer's acoustic started feeding back....what the hell!??? The only thing that had changed is that the sliding door on the back of the all metal back wall of the stage was open during sound check and it was closed when they started. Next time were there, we sound checked with the door closed.
It's the little things that will get ya'.......