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Author Topic: Saturday Night - Gig gone bad  (Read 13020 times)

lindsay Dean

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Re: Saturday Night - Gig gone bad
« Reply #10 on: June 26, 2014, 01:40:43 PM »

They heard feedback from their IEMs before you did? that's crazy. Honestly, you should try to make things feedback (a little bit, doesn't have to be loud) during a setup/check so you know where the limits are.

Also put the dang RTA away. I had when I go somewhere and see people using smaart during a live show and while I love smaart it is for tuning and setting up the system no for use during a performance - USE YOUR EARS ONLY!

I second that, it seems the magic fixes are too heavily emphasized. they can get you in the ballpark but can't hit that home run swing.
 By the way all these posts about setting it flat, a "flat" setting on mains sounds just that, flat.
 You still have to have an ear to tune and mix,some people develop that over time, some do not. Just because you can hook it up/install it does not mean you can mix.
    Trust your ears, use" magic" sparingly, accept forgiveness from the band,  push on,.
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Re: Saturday Night - Gig gone bad
« Reply #11 on: June 26, 2014, 02:07:35 PM »

.....while I love smaart it is for tuning and setting up the system no for use during a performance - USE YOUR EARS ONLY!

You obviously know it all.  Now those of us who use real time spectrum analysis as a part of our show-time tool kit can put that stuff away and follow your lead, oh omniscient one.
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Steve Garris

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Re: Saturday Night - Gig gone bad
« Reply #12 on: June 26, 2014, 02:12:48 PM »

I would first like to say "Welcome to live sound".

You're getting really good replies here. Take note of what Nils and Rob posted. Move around the room while the band is playing. If my band complains about something they here on stage, then I get up there and listen while they're playing.

Can you control the X32 remotely with an iPad? I use a DL1608 / iPad mixer, so I can go wherever I need to and make the necessary changes.

If the feedback is low-mid or lower, it is acceptable to make the system feedback purposely, then dial out that offending frequency. Also agree that using gates can help.
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Art Welter

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Re: Saturday Night - Gig gone bad
« Reply #13 on: June 26, 2014, 02:20:28 PM »

1)I have no issue with digital theory or the operation of digital mixers however it seems that I am developing bad workflows on the X32 and not keeping my head up.

2) I failed to recognize a low frequency wave that had built up on the stage and developed into feedback.  It was centered around 300hz.  We don't use any monitor speakers I run 5 monitor mixes with in ear units.  The feedback had to be from the subwoofers and back into a vocal or possibly drum mic.  Bass and Electric Guitar are DI.  Only vocal and drums have microphones.

3)   I handled the feedback by reducing master gain then bringing up instruments and rebalancing the vocals.  I tried an aggressive low pass up to 200hz shelf and it sounded like crap so I had to abandon that idea.  Then I tried applying a narrow 9db dip using the parametric centered at 200hz and about 120hz wide with a fairly steep roll off.  This solution seemed to work during the second set the however in the last set of the night we once again had a very quickly building feedback event. 
4)My guess is some different samples from the electronic drums hit the resonant frequency and IM products and once again created a sort of bass trap on the stage.  We have worked this room before but our usual KW181 subs were not available and I used some physically much larger Mackie dual 18" that have significantly deeper low end extension than the KW's.
5)My question is, how can I in the two weeks I have to the next gig improve my workflow beyond additional practice on the X32 and start to rebuild the confidence of my band mates?   
Scott,
1) Only look at the board when you are actually making adjustments, and learn to push faders without having to look at them.
2) 300 Hz is not low frequency, and should not be reproduced by "subs".
The balance between subs and tops should be set before the show starts, and typically should be around 100 Hz.
You should get a pair of isolation headphones (I like the GK Ultraphones) so you can listen to the individual channels (and headphone mixes) to determine where the origin of the feedback is, and correct it there, not globally.
3) Reducing master gain, then bringing up instruments again is not a net change regarding gain before feedback, and if you have compressors set post fader, can result in even more feedback, as gain has been increased, while the compressors limit output level. If the feedback was centered at 300 Hz, cutting at 200 is the wrong choice. Loads of compression (more than 6 dB on peaks) may sound good in the in ears, but can easily result in feedback that is hard for you to hear, masked by other louder sounds.
4) Bass traps are not created by samples, they are properties of rooms. As well as keeping eye contact with the band at all times, you need to walk around and check out the room and stage to hear what it sounds like in various spots. Had you done that, the problem would have been apparent.
5) Set up the system in the largest room (or outdoors) and get the top and bottom processing set correctly and equalized. If you don't have a system processor, get one. After getting the system properly equalized, set up the vocal mics and start experimenting- other than a HP around 80 Hz, and a low mid cut to deal with the proximity effect, they should sound natural when you speak through them. Experiment with the compressors- you can "ring out" the system without blowing anything up when the compressors are set at a high ratio with lots of gain reduction, probably what was going on at the last gig.
Once you have identified and corrected the problems, tell your band mates what you have done.

Art
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Scott Holtzman

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Re: Saturday Night - Gig gone bad
« Reply #14 on: June 26, 2014, 02:21:03 PM »

They heard feedback from their IEMs before you did? that's crazy. Honestly, you should try to make things feedback (a little bit, doesn't have to be loud) during a setup/check so you know where the limits are.

Also put the dang RTA away. I had when I go somewhere and see people using smaart during a live show and while I love smaart it is for tuning and setting up the system no for use during a performance - USE YOUR EARS ONLY!

The RTA is built into the board, I can look at any input, buss DCA group etc.  It is very easy to see feedback on it.

Anyway, maybe I am not being clear.  Nobody heard feedback in the IEM.  What I think happened is a troublesome frequency was initiated by the electronic drum pad.  That frequency was "trapped" by the shape of the stage and in my current working theory of sufficient amplitude to be picked up by the kick mike.  The gate opened and the compressor "sucked up" for lack of a better word the feedback and created it's own feedback fed by the compressor.

Due to my distance from the stage, the amount of crowd.  The position of the subs I believe the bass feedback was of sufficient amplitude on stage to be felt and heard before being noticeable at FOH.  By all means my ear should have caught it.  I also believe I had my head down trying to get the mix set as we did not have time for a sound check, line check or to ring out the room.  We were not allowed to setup until after a party and by then the venue was packed.

For those asking about moving around.  I use the iPad app for the X-32 and try and move around the house as much as possible.

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Scott AKA "Skyking" Holtzman

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Scott Holtzman

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Re: Saturday Night - Gig gone bad
« Reply #15 on: June 26, 2014, 02:35:43 PM »

Steve -- Thanks for the welcome.  I participate in other forums and no how "same old questions" from newbs can get the seasoned vets down.  I was truly in a know over this for the past few days and thought it would be a great opportunity to join the community.  I might also possibly have something useful to share.

Art - Great feedback, let me address your points.

1  - Agree, and working to improve this and have as good a memory for the x-32 as I did for the analog boards
2  - You are right, the crossover is actually at 90hz.  I believe that the slope of the crossover is 3db per octave so if the offending frequency was 300hz that would only be 6db down off the back of the crossover.  I absolutely need ears.  I have been thinking about getting another IEM pack so I can use the solo from the iPad and listen anywhere in the room.  Compressors are pre-fader as are the gates.   
3 - I agree completely see my previous post
4 - I understand this, my theory is that the electronic drum produced a waveform of sufficient amplitude and duration to trigger the trap effect and ultimately the feedback product.
5 - Already done.  I have the previous generation (not the ipad controlled) Driverack.  However it is still in the box.  Experience has shown me that sometimes that's the best place for outboard gear when you are just getting your workflows down on a new desk.  I also was trying to get out of lugging around extra gear however I just got the S-16 digital snake so I could put it in that equipment case.

Thanks again.
3 -
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Scott AKA "Skyking" Holtzman

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Art Welter

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Re: Saturday Night - Gig gone bad
« Reply #16 on: June 26, 2014, 02:43:28 PM »

1)Nobody heard feedback in the IEM.  What I think happened is a troublesome frequency was initiated by the electronic drum pad.  That frequency was "trapped" by the shape of the stage and in my current working theory of sufficient amplitude to be picked up by the kick mike.  The gate opened and the compressor "sucked up" for lack of a better word the feedback and created it's own feedback fed by the compressor.
2)I use the iPad app for the X-32 and try and move around the house as much as possible.
1) If anyone had the kick drum up in their mix, they heard the feedback in their IEM. The use of compressor on a kick drum is asking for feedback, and will increase the tendency of an inconsistent kick drummer becoming even worse. Use no compression, and set the gate so the drummer has to kick reasonably hard to open it, and he will. If any other instrument or sample is loud enough to open the kick gate, things are seriously wrong either with the drum tuning, drummer, mic position, EQ, gate settings, or a combination thereof.
2) Excellent, but obviously "as much as possible" needs to be more ;^).
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Jay Barracato

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Re: Saturday Night - Gig gone bad
« Reply #17 on: June 26, 2014, 02:50:15 PM »

They heard feedback from their IEMs before you did? that's crazy. Honestly, you should try to make things feedback (a little bit, doesn't have to be loud) during a setup/check so you know where the limits are.

Also put the dang RTA away. I had when I go somewhere and see people using smaart during a live show and while I love smaart it is for tuning and setting up the system no for use during a performance - USE YOUR EARS ONLY!

Load of crap... The spectrograph in SMAART is amazingly useful during a show to display your cue bus. When i am separated from the band by 150 feet and 500 people and I am trying to mix monitors from FOH, being able to see the response in a single channel or monitor channel is an amazing tool. Typically I can spot hot frequencies before they can be heard as feedback and fix things before anyone even knows there is a problem. The more complex the system, the more useful this tool becomes.

i see no reason to give up perfectly appropriate tools.
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Jay Barracato

Art Welter

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Re: Saturday Night - Gig gone bad
« Reply #18 on: June 26, 2014, 02:56:29 PM »


2  - You are right, the crossover is actually at 90hz.  I believe that the slope of the crossover is 3db per octave so if the offending frequency was 300hz that would only be 6db down off the back of the crossover.  I absolutely need ears.  I have been thinking about getting another IEM pack so I can use the solo from the iPad and listen anywhere in the room.  Compressors are pre-fader as are the gates.   
Scott,

Isolation phones are a lot easier to put on and off than sticking in IEM, though having them plugged in to a portable pack would be cool.

There is no such thing as a 3 dB per octave electronic crossover (a single pole is 6 dB), but if there was and it was set at 90 Hz, it's output would be -3 dB at 90 Hz, -6 dB at 180 Hz, and -9 dB at 360 Hz.
What "crossover" were you using?

Art
« Last Edit: June 26, 2014, 02:58:41 PM by Art Welter »
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Scott Holtzman

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Re: Saturday Night - Gig gone bad
« Reply #19 on: June 26, 2014, 03:17:20 PM »

Scott,

Isolation phones are a lot easier to put on and off than sticking in IEM, though having them plugged in to a portable pack would be cool.

There is no such thing as a 3 dB per octave electronic crossover (a single pole is 6 dB), but if there was and it was set at 90 Hz, it's output would be -3 dB at 90 Hz, -6 dB at 180 Hz, and -9 dB at 360 Hz.
What "crossover" were you using?

Art

We were using EV ZLX-15P that has a built in crossover.  I just looked no specs on it in the manual.  I assume it's a 3rd order Butterworth, that's a bunch of assuming.  What concerns me is my fundamental assumption that this crossover was 3db per octave which I now see is wrong.

Something I thought I knew and would have argued to the death, major sigh

Please feel free to tell me that I am all wet on my bass trap theory, that is also a damn good point on the kick gate.  Although from what these guys described this bass wave on stage was visceral and building very fast.  I have a call into the drummer, who is a buddy to see if he heard in his ears.  He is the only person that takes any kick in their monitor mix.

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Scott AKA "Skyking" Holtzman

Ghost Audio Visual Solutions, LLC
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ProSoundWeb Community

Re: Saturday Night - Gig gone bad
« Reply #19 on: June 26, 2014, 03:17:20 PM »


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