Yesterday, I used GP to play live at a one day market. Some of my songs featured the UJAM automatic bass player. I was playing in a rotunda and at times I was getting the most awful and loud bass resonances. I tried adding a feedback destroyer on the main mix but that didn’t help. I was wondering if a compressor vst would have helped tame some of the rogue loud bass notes. If a compressor is the answer, can somebody suggest which one to get hold of?
Hmm… i guess, a good EQ would be the better choice in this case.
A compressor won’t change the reaction of the room to particular frequencies.
Maybe this one:
It has a built-in RTA!
Connect this EQ to a microphone and play a pink noise over the speakers, then you can easily see which frequencies pop out and then correct them with up to seven EQ parametric EQ bands.
The problem is, its impossible to play live and do what is suggested. I did a sound check and everything sounded fine. It was only later that a new song brought in the bass as I was halfway into the set that the problems arose…I couldn’t stop then with a crowd there. I just turned down the volume to try and minimize the resonances. Very unsettling when I was expecting to have basically an open air sound with no restriction as all.
Then maybe you should just include some songs with that bass in your sound checking.
In that case, the solution is for sure in hardware: depending on your amp or PA system, you might quickly cut on the fly the unwanted frequency. instead of turning down the volume.
In order to anticipate this problem, try to reproduce the issue at home by cranking up different frequencies on your PA system until you get disturbing frequencies (whether in low, mid or high ranges). Then, on live, you will be able to find more easily and quickly the relevant frequencies.
Would it be possible to run some sort of sound check using a sound file with a range of frequencies using maybe white noise? Then set the vst mentioned on rtf mode to pick up these errant frequencies. This could be a gigfile with nothing else in it but the white noise which could be run at sound check. When I program at home, everything is fine (as it always is!). I must admit that this aforementioned gig took me by surprise with the bad sound. I’ve played outside many times at markets and such and never had this frequency problem before. The gazebo was a permanent structure made of hard materials on a concrete floor. I suspect that the frequencies generated in the roof which was open and had a vaulted ceiling.
Al, if you use a 19" Rack, you should consider buying something like the Behringer DEQ2496 which would offer all you need for a room/Sound correction, including a pink noise generator, a mic-in for a measuring microphone, a RTA, a parametric EQ and a graphical EQ (and some other useful stuff).
I used one at home for room correction at my music-listening spot and it worked great!
Or you could run a second instance of GigPerformer, Connect them via virtual cabling, and use it for EQing and compressing and such…
Thanks for tip Erik. I actually had one of those Behringer units briefly, but I found it just too hard to figure out let alone use. When I sent it back, I asked the shop guy about something easier to use and he sent me a DBX Go Rack which is basically a set and forget device. I haven’t been using the Go Rack as I never had this resonance problem before, but I’ve just patched it in to the system again.
Just asking anyone reading this - Is the bass resonance problem I had feedback, or is it likely to be some sub harmonic running in sympathy with my generated bass?
It makes a lot of sense to calibrate sound in an enclosed and silent place where you will play, and in any case it will greatly reduce the chances of problems, even in other places.
But keep in mind that even a sound check before playing will never offer a seamless solution.
i.e. checking sound in an empty hall before playing does not prevent from facing sound degradation due to the absorption effect of a large audience.
Even more so, by playing outside or in a noisy place, you might be confronted with unpredictable extraneous noises, excessive proximity effects or other unwanted causes that lead to the problems you experimented.
Imo, the safest course may be to learn to easily recognize frequencies in order to respond quickly to any feedback, rumble, etc by cutting them on your mixer in the same way as you turn down treble when hearing hiss.
There are many free apps (such as Simple Feedback Trainer on Windows) that will help you become a real sound professional
In most cases, it is better to rely on your ears and your fingers rather than technology.
Lowering bass frequencies will eliminate sub harmonics if required