I Guess I'll Start This Off

Re: I Guess I'll Start This Off

I was recently at a school to take care of sound system issues their gym system has had for some time (ever since it was installed I would say!!!)
What I found was:
In the rack was a small Shure mixer for use during games and simple audio needs. They also have an input to the system
from another 24 channel mixer used during stage productions. The installer had set up a relay to select what mixer would feed the system. Here where it gets crazy......the installer took the negative (-) outputs from the two mixers and the (-) input to the system and tied them all together and only used the relay to switch the positive (+) side of the balanced connections. All inputs and outputs were fully balanced. I'm guessing the installer did not understand the difference between ground and (-) in a balanced connection.

There was a small 15 inch sub/low cabinet in the system driven from it's own amp channel with no form of crossover what so ever anywhere from the input to the amp all to the speaker cabinet, yes that single 15 was just barking out full range audio.

Two mic inputs were really noisy, found out they were split between the rack mount mixer and the 24 channel stage production mixer......using RDL line level amps with the gain cranked wide open on each one.

I got the system working better for their graduation, going back this summer to install a DSP with presets for different system uses.
 
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Re: I Guess I'll Start This Off

Pat Latimer said:
Damn! What was their reasoning behind the graphics on inserts? I'd love to hear that explanation!

Pat
Click to expand...

I used to do that all the time. However that was several decades ago, when you could only get sweepable eq on high end consoles-and many consoles only had a 3 band fixed eq. Thebetter ones had fixed 4 bands.

So the outboard eq's were used to give more control over the sound.

Oh how the times they have changed.
 
Re: I Guess I'll Start This Off

Ivan Beaver said:
I used to do that all the time. However that was several decades ago, when you could only get sweepable eq on high end consoles-and many consoles only had a 3 band fixed eq. Thebetter ones had fixed 4 bands.

So the outboard eq's were used to give more control over the sound.

Oh how the times they have changed.
Click to expand...

True. Ivan, I almost stepped on my tongue and was going to contradict you. Did you see the photos?

Pat
 
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Re: I Guess I'll Start This Off

Pat Latimer said:
True. Ivan, I almost stepped on my tongue and was going to contradict you. Did you see the photos?

Pat
Click to expand...

Pat,

I actually agree with Ivan. Patching a graphic to a channel insert is a trick I use quite a bit to expand the eq control of lower end boards. Looking back at the photos I can see that the 15 band eqs had already been zeroed out because the one I wasn't using is flat. This was a corner stage that was pretty small. I basically set up my gains on the board and had the board pretty flat and the system did not have any feedback until I introduced the musicians. Then three of the instrument condensers (on the outside corners) started feeding back like crazy. Because I had no where to go on the house graph, I was forced to make due on the inserts, which was actually better than making due just on the board eqs. Given that the only bands that were even close to 0 were 80-120 and everything over 12k on the house graph, it may be that the head house tech (who wasn't present at the show) was trying to correct something that should have been corrected at the crossover.

On shows where I have had an opener doing a one mic setup before the main band which was using close mics, if I am on my own system I tend to save different eq setups on my processor, When I am one someone elses rig, I just insert an eq on the one mic channel.

The real oddball thing was the total amount of cut and then makeup gain used in three separate places of the signal chain (board, insert, output eq). I never did see the crossovers. I am not really sure I wanted to.
 
Re: I Guess I'll Start This Off

Jay Barracato said:
Pat,

I actually agree with Ivan. Patching a graphic to a channel insert is a trick I use quite a bit to expand the eq control of lower end boards. Looking back at the photos I can see that the 15 band eqs had already been zeroed out because the one I wasn't using is flat. This was a corner stage that was pretty small. I basically set up my gains on the board and had the board pretty flat and the system did not have any feedback until I introduced the musicians. Then three of the instrument condensers (on the outside corners) started feeding back like crazy. Because I had no where to go on the house graph, I was forced to make due on the inserts, which was actually better than making due just on the board eqs. Given that the only bands that were even close to 0 were 80-120 and everything over 12k on the house graph, it may be that the head house tech (who wasn't present at the show) was trying to correct something that should have been corrected at the crossover.

On shows where I have had an opener doing a one mic setup before the main band which was using close mics, if I am on my own system I tend to save different eq setups on my processor, When I am one someone elses rig, I just insert an eq on the one mic channel.

The real oddball thing was the total amount of cut and then makeup gain used in three separate places of the signal chain (board, insert, output eq). I never did see the crossovers. I am not really sure I wanted to.
Click to expand...

I have heard of people doing this before. I just never saw the need for it in the situations I have been in. Normally, I just used the channel eq on the insert. Learn something every day.

Pat
 
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Re: I Guess I'll Start This Off

Adam Robinson said:




Underbalc speakers at a theatre I was at this year...



Don't know if you can tell or not, but this is a cut-only EQ
Click to expand...

Did you mean "hack only"????
 
Re: I Guess I'll Start This Off

Pat Latimer said:
I have heard of people doing this before. I just never saw the need for it in the situations I have been in. Normally, I just used the channel eq on the insert. Learn something every day.

Pat
Click to expand...

I still have a pair of 1/3 ocatave graphics in my FOH ready to patch to inserts if needed. To be honest I haven't used them in years, but when you need it, you usually really need it. And, despite numerous rack remodels, they always end up back in the rack.
 
Re: I Guess I'll Start This Off

Here's a couple more installs that make you ask what are they thinking!

About 10 years ago I was in a cities new government building as the installers were finishing the AV install in the council meeting room that consisted of four small JBL control series speakers, goose neck podium mics at each council members seating position, mic for audience questions and play back inputs. I watched as the installer carved out the biggest, deepest smiley face I have ever seen on the system 31 band EQ's. Not to let that go without comment I said "that's a low frequency boost for those speakers" his answer was....."we let the feedback eliminator take care of that"



More recently I was looking over a new school building for a school district that I provide audio production for at their Christmas and spring concerts while the install company was doing the training on the system in the gym. Upon turning on the power sequencer for the system I was hearing all kind of pops and cracks as the system powered up as well as when they powered it off. When the system was on I walked and listened to the three speakers covering the bleachers and thought there was a big such out cancellation between the speakers. Looking at the rack I noticed first that the power amp was plugged into sequence position #1 and the power amp was in bridged mono mode but wired for normal stereo output with two pair of speaker lines on one output and a single speaker line on the other. I commented to the installer about the popping sound during power up and down with the power amp plugged in the first position on the sequencer, his comment was that the system DSP had not been fully adjusted yet and that would take care it!!!!!! Yes he said that!.

As for the bridged mono power amp, he said the system is mono with just the three speakers, I tried to explain about one amp channel polarity being inverted causing the suck out between speakers and the amp should be in stereo mode and use the input "Y" switch on the amp, the amp is a Crown CTS series..deer in the headlights is the best way I can describe his response. I won't even go into had bad the school music rooms were configured and they were complaining about the problems in the music rooms.

Both of the above install companies are doing installs as you read this, they are large companies, neither of the installers were 18 year old summer either.

I did offer the school to take care of the issues and bill the contractor for the service call, being still under warranty the installer was going to take care it I was told.

Rant over!!!!
 
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