Members 6tring Posted July 14, 2003 Members Share Posted July 14, 2003 Last night at our gig we were getting a low frequency rumble out of the subwoofers. We could not find what was causing it. We run the bass guitar and the foot kick for the drums throuh the subs. We tried moving the kick mic around a little and moving the the pillow and sound deadening blanket inside the kick but to no avail. I know this is limited information but anyone got any ideas? Link to comment Share on other sites More sharing options...
Members dirtyragamuffin Posted July 14, 2003 Members Share Posted July 14, 2003 If you can, solo each channel till you find the offending rumble, then engage a high pass filter. What kind of console was it and how low do the subs respond to? Do the sub amps have HPF's on them? cutting below 50hz *could* fix it up if it's a real low rumble. Link to comment Share on other sites More sharing options...
Members OMNIFEX Posted July 14, 2003 Members Share Posted July 14, 2003 Hmm . . . . . No Turntable due to live music. How about footsteps? You know, walking, dancing, stomping, jumping on the stage? Possibly, the mic is picking this up? Just a thought Link to comment Share on other sites More sharing options...
Members tlbonehead Posted July 14, 2003 Members Share Posted July 14, 2003 As stated,punch out the channels until you find the main culprit. Hollow stage maybe,or a hot frequency of the room. A lot of times,it seems to happen in the 70-100hz range. How many bands of main EQ do you have? Do you have an EQ on the kick? How about gates on the drums? Link to comment Share on other sites More sharing options...
Members 6tring Posted July 14, 2003 Author Members Share Posted July 14, 2003 Originally posted by OMNIFEX Hmm . . . . .No Turntable due to live music. How about footsteps?You know, walking, dancing, stomping, jumping on the stage?Possibly, the mic is picking this up?Just a thought Slightly elevated, Hollow stage platform. No dancing on stage but the drums could be the culprit on the hollow platform. We do not get this noise at other clubs. Link to comment Share on other sites More sharing options...
Members ezstep Posted July 14, 2003 Members Share Posted July 14, 2003 I am assuming that this is not the 60-cycle hum that we all have grown to love. This is a long shot, but it happened to us. We could actually see the sub's cone moving, but it was so slow that there was no sound. There was sound when we played, but, even with nothing plugged into the board, we could see the cone vibrating. We tried a different power amp, different crossover, different eq unit, different fx unit, switched cords, then discovered that it was the mixer itself. We dusted off my old Yamaha 12-channel and used it for over a year. The other "newer" mixer was still under warranty, but we never swapped the new back in for theh Yamaha when it was repaired. I suggest you do the same. Test a different power amp, different (or by-pass) x-over, eq, fx, etc., then as other have stated, check each channel on the mixer. Our problem was that we could not isolate a single channel. It seemed to move the speaker across the entire mixer. Link to comment Share on other sites More sharing options...
Members tlbonehead Posted July 14, 2003 Members Share Posted July 14, 2003 Originally posted by ezstep I am assuming that this is not the 60-cycle hum that we all have grown to love. This is a long shot, but it happened to us. We could actually see the sub's cone moving, but it was so slow that there was no sound. There was sound when we played, but, even with nothing plugged into the board, we could see the cone vibrating. We tried a different power amp, different crossover, different eq unit, different fx unit, switched cords, then discovered that it was the mixer itself. We dusted off my old Yamaha 12-channel and used it for over a year. The other "newer" mixer was still under warranty, but we never swapped the new back in for theh Yamaha when it was repaired. I suggest you do the same. Test a different power amp, different (or by-pass) x-over, eq, fx, etc., then as other have stated, check each channel on the mixer. Our problem was that we could not isolate a single channel. It seemed to move the speaker across the entire mixer. A low pass cut filter should have pretty much eliminated that. Were you using one? Link to comment Share on other sites More sharing options...
Members 6tring Posted July 14, 2003 Author Members Share Posted July 14, 2003 Originally posted by dirtyragamuffin If you can, solo each channel till you find the offending rumble, then engage a high pass filter.What kind of console was it and how low do the subs respond to? Do the sub amps have HPF's on them? cutting below 50hz *could* fix it up if it's a real low rumble. We use a Mackie 16 channel board. HPF'S??? We do have the ability to set the frequency on the amps so they are set up for subwoofers specifically and so that only lows frequency signals are going to the subs but I do not know how it is set. I will check on that however. Link to comment Share on other sites More sharing options...
Members ezstep Posted July 14, 2003 Members Share Posted July 14, 2003 Originally posted by tlbonehead A low pass cut filter should have pretty much eliminated that. Were you using one? That particular board didn't have one, and the x-over was quite primitive as well. The guitarist purchased the whole rig from some sort of "repo" deal. I wouldn't give him $100 for the whole rig, but he was happy. Link to comment Share on other sites More sharing options...
Members tlbonehead Posted July 14, 2003 Members Share Posted July 14, 2003 Originally posted by 6tring We use a Mackie 16 channel board. HPF'S??? We do have the ability to set the frequency on the amps so they are set up for subwoofers specifically and so that only lows frequency signals are going to the subs but I do not know how it is set. I will check on that however. A lot of amps have low cut filters in the 30-50hz range. (HPF) Some EQ's and crossovers do as well. How many bands of EQ are you running. Separate EQ on kick and bass guitar? Do your mixer channels have sweepable mids? How low do they go,if so? Link to comment Share on other sites More sharing options...
Members RickJ Posted July 14, 2003 Members Share Posted July 14, 2003 Cut the bass on the strip EQ of every vocal mic. That's my guess, anyway: The mic is coupled to the stand, which is coupled to the stage, which resonates into the FOH speakers and causes the low-freq feedback loops. Boosting the bass in the vocal mics of a club system is a common mistake. It's not part of the frequency range of the human voice. Another "look-see" would be to swap any cast-iron mic stand bases with tripods. Tripods help isolate the mics versus the coupling effect of the heavier stands. Link to comment Share on other sites More sharing options...
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