Film-Tech Forum ARCHIVE: Subwoofer is humming...help!

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Posted by Aaron Garman (Member # 1653) on 07-24-2003, 02:25 AM:

Hello all. For awhile, one of our auditoriums has had a distinct low frequency hum emminating from the subwoofer and it will not go away. The only reason it is still there is because most people don't notice it, but it is blatantly there. Anyhow, I'm trying to figure out what it could be. Our system for the auditorium is as follows:

USL JSX 1000 Processor
USL Monitor
DA20 with Cat. 700 reader
Peavey CS 800 amps
Not sure on speakers

Anyhow, I thought it may have been a lose cable or dirty cable. So I checked everything upstairs and all was good. The only thing I could imagine it would be would be one of the cards in the JSX 1000. Our tech was in this week, looked into the problem, and said he got rid of the hum. Well, I went into the auditorium on my shift tonight (after he left) and lo and behold the hum is STILL there. I saw his report and it said it was a loose card, and he said he fixed it. Any thoughts? This used to be our best auditorium, if not the best in the whole area, but now it is a shadow of its former self. I just want it to sound the way it used to, but no one seems to really care. Maybe someone here will.

AJG

[ 07-06-2004, 01:20 AM: Message edited by: Aaron Garman ]

Posted by Brad Miller (Member # 2) on 07-24-2003, 03:33 AM:

That's not enough info to fully diagnose your problem, but you've got to start troubleshooting somewhere, so do this first.

Turn the fader to 0. Is the hum still there? If the hum remains it is post processor. If the hum varies in volume with the fader, then it is inside the processor. Odds are though that you have a grounding issue with the way the rack was wired. Anyway, first things first, let's rule out the processor and go from there.

Posted by Tim Reed (Member # 137) on 07-24-2003, 09:19 AM:

If it's a powered s/w, like a Kintek KT-90, go backstage and unplug the audio cable feeding the unit. If the hum remains, the amplifier in the sub is out. If that is the case, also check the speaker cones because they may be blown. A common failure mode for those amps is they go square wave, and quickly blow the speakers.

Posted by Randy Stankey (Member # 64) on 07-24-2003, 09:41 AM:

Brad,

Doesn't this sound suspiciously like that old problem where a "certain company" pre-wired all of the racks and grounded both ends of the shields?

I've had that happen a lot of times. Unhooking one (upstream) end of the shield solved the problem many times for me.

Posted by Darryl Spicer (Member # 711) on 07-24-2003, 10:52 AM:

Randy is right about the ground loop problem, it can cause such noise. We took all of our racks and removed that ground connection on one end and removed the terminal strips and wired all speaker wiring straight in.

The other possable problem, and you listed it in your equipment, is the peavy 800amp introducing hum into the subs. remove the amp and try conecting the subs to another amp that is working fine and see if the problem is still there. If it goes away get your amp repaired. If it is still there it could be something else.

Posted by Gordon McLeod (Member # 33) on 07-24-2003, 10:58 AM:

Unplug the input to the sub amp and see if it goes away
Also since the peavey used 1/4 jacks they may be a bit less than ideal in the quality of connection
Also if this rack was built by the unamed company I think then also try disconnecting the sub from the monitor both the processor and the speaker connection to the monitor

Posted by Adam Fraser (Member # 1074) on 07-24-2003, 12:36 PM:

We have had thew same problem, turning off the subwoofer amp until after the xenon is struck solves the problem (either the disturbance when striking or a grounding problem is our guess). Although not a permanent solution it has worked until we can get our tech up here for the routine maintainence instead of spending the money for the 7 hour roundtrip to fix one small problem.
Our Equipment-
Peerless Magnarcs with Kniesley conversion
Altec 944? amps for subs and surrounds.
Ashly for stage channels

JBL Speakers

Posted by Aaron Sisemore (Member # 145) on 07-24-2003, 02:02 PM:

quote:
since the peavey used 1/4 jacks they may be a bit less than ideal in the quality of connection

Gord, the Peavey CS800 also had XLR jacks.

-Aaron

Posted by Gordon McLeod (Member # 33) on 07-24-2003, 02:06 PM:

hopefully then they had used them as 1/4 phone is the most unreliable connector I have seen

Posted by Aaron Garman (Member # 1653) on 07-24-2003, 02:09 PM:

Thanks guys. I'll try to check this stuff out as soon as I can. Again, no one really cares that much about this problem there and if they see me tinkering with one of the racks, they may assault me with questions. Brad, I think it's in the processor because when I flip the USL monitor to processor, I can hear the hum out of the monitor too. But I'll give what you said a try and see what I can do. Thanks again everyone!

AJG

EDIT: I chose to get rid of my angry comments. Looking back, they weren't necessary.

[ 07-06-2004, 01:22 AM: Message edited by: Aaron Garman ]

Posted by Gordon McLeod (Member # 33) on 07-24-2003, 02:18 PM:

It could also be on the input to the processor in a connection to the nonsync to the digital player to the projector
ground related hum is a bitch to find and takes a lot of time
Best is break the system in the middle and that will eliminate 1/2 the possibilities

Posted by Manny Knowles (Member # 1171) on 07-24-2003, 05:09 PM:

All of the above is good advice. You're basically trying to isolate the source of the hum first and then deal with the problem.

However, I am compelled to add a few words of caution.

quote:
...if they see me tinkering with one of the racks, they may assault me with questions.

Which makes me wonder if you are venturing into an area where you aren't supposed to. Sure, it's a simple problem and you could probably solve this but there is something to be said for having proper prior approval to alter the setup.

quote:
I'm so fed up I'm just gonna do whatever because the situation is ridiculous along with other booth problems.

Actually, this is the part that made me raise an eyebrow. Two wrongs don't make a right. Go ahead and do the simple tests like the one Brad suggested and if you manage to isolate the problem then you should talk to your manager before changing anything.

quote:
If I told my tech, something tells me he won't care.

This is an example of mind-reading. Even so, if you really cannot give your tech the benefit of the doubt then I still have to point out that two wrongs don't make a right.

Deal with your manager. Show him/her that you have respect for the chain-of-command and point out that you've only (a) noticed and (b) researched the problem. It's a simple problem and, depending on how it is handled, it could be the difference between a commendation or a letter of warning.

The best way to be smart is to be right.

Posted by Aaron Garman (Member # 1653) on 07-24-2003, 05:17 PM:

Oh, forgot to mention, I did run a show in there once with the two sub amps off. This did eliminate the hum however. It appears that all conections for speakers on the amps use bare wire, and the line connections use 1/4" phono plugs. Also, the LCR channels are being biamped with a crossover on each of them. Again thanks for the help and I'll try to check the system out when I go in tonight.

AJG

Posted by Bruce Hansen (Member # 281) on 07-24-2003, 05:26 PM:

Maybe it's humming because it doesn't know the words.

Sorry, I just couldn't resist.

Posted by Darryl Spicer (Member # 711) on 07-25-2003, 02:37 AM:

swap your format card with another format card and see if the problem follows it. Volume for the subs is controled on these cards. One easy way to find out if it is that card is by opening the port and listen then turn the volume up and see if the hum gets louder. this is with no film running and the processor in stereo mode.

Since you are using two amps to power the subs I would say you have a total of four behind the screen turn one amp off go down and listen to the sound or just listen to the subs with nothing playing and see if you still hear the hum. then do the same for the other amp. If you hear the hum in both amps then there is a processor problem if only one of them it could be just the amp.

Posted by Aaron Garman (Member # 1653) on 07-25-2003, 03:11 AM:

Hello all. Well I investigated a few things tonight, and here is what I got. The humming remains with all amps on and the processor on. However, when I adjust the volume on the processor, the hum remains. Also, the hum disappears when all amps are on, but the processor is off. The hum also disappeared slightly when the processor was on, and the LCR and Surround amps were off.

I just read your post Manny, and I totally understand your advice. My main goal here was not to tinker with anything, just figure out what the hum was coming from. I would not change anything without approval from my superiors. The trouble is, most people around our theatre including our tech are very apathetic to recent booth problems, which just makes things frustrating. I know two wrongs don't make a right; I was writing that post with too much emotion and wasn't thinking. Thanks for bringing me back down to Earth. As far as following the chain of command, I totally have. I noticed the problem months ago and researched it for the past couple weeks, and nothing has been done about it. I've told at least 3 managers, as well as the tech himself. He said he would look into it, and he did a month and half after I brought it to his attention. Then, he claimed he fixed it. I really do feel ashamed that I have to get upset, but the whole thing just gets to me. Again, the apathy I have seen is extremely discouraging. Anyhow, thanks for all the help guys, and I'll see what I can do.

AJG

Posted by Manny Knowles (Member # 1171) on 07-25-2003, 09:30 AM:

quote:
Also, the hum disappears when all amps are on, but the processor is off.

This rules out your amplifiers themselves but the trouble could still be with the connection into the amps from the processor. That's what I would check next with one amp on at a time.

quote:
when I adjust the volume on the processor, the hum remains.

Just curious if this means that the hum gets louder and softer when you change the fader setting? If you turn the fader all the way down, does the hum go away?

Posted by Tim Reed (Member # 137) on 07-25-2003, 10:09 AM:

Okay, that sounds like a ground loop, then. Or a bad system ground in your rack. All the chassis have to have a good electrical bond to the rack (the mounting screws may even be loose). Sometimes, the paint has to be scraped or filed off under the ground and/or mounting screws. The easiest way, though, is to just connect all of the chassis together with a single grounding wire, and then attach the other end of it to bare metal somewhere inside the rack.

Posted by Aaron Garman (Member # 1653) on 07-25-2003, 10:26 AM:

When I adjust the fader, whether it be 0 or 7, the hum remains the same volume. [Confused]

AJG

Posted by Manny Knowles (Member # 1171) on 07-25-2003, 11:18 AM:

Then I'd say the fault lies in the connection of the processor to the amps. It's probably those 1/4" plugs.

A simple test would be to turn on the processor and just one amplifier (of the channel that hums the most) and then unplug the 1/4" plugs (remember which one goes where if there are 2). The hum will probably go away. If so, then you have successfully isolated the cause of your hum.

Next item on the agenda would be to go ahead and report your findings to your tech and your theatre manager (a copy to the manager can force a lazy or apathetic tech to deal with the issue).

Posted by Michael Schaffer (Member # 1204) on 07-25-2003, 11:20 AM:

quote:
Maybe it's humming because it doesn't know the words.

I had the same idea, but I resisted it.
I had a hum problem recently with an UltraStereo processor, and it turned out that the problem was caused by a faulty power supply.

Posted by Randy Stankey (Member # 64) on 07-25-2003, 08:12 PM:

quote:

Michael S: I had a hum problem recently with an UltraStereo processor, and it turned out that the problem was caused by a faulty power supply.

Good idea!

Here's a spin-off on that idea:
The power supply goes bad and somebody plugs in the backup supply to get the processor running in "emergency mode". In order to do that you have to press the "Bypass" button on the format module. All other functions of the processor are shut down and it runs off the backup optical preamp. First, it's noisy as hell. It's only meant to "save the show", not to run long-term. Second, people often run the booth with one or more overhead lights turned on full time. Because there's little to no noise reduction, any 60 Hz hum from the lights can be heard in the system. (Less of a problem if you have IRED optical sound.)

Sometimes that button just gets pressed in by some bone head but nobody ever notices. 1) Check to see if the button is in. 2) Check the power supply by swapping it with a known-good house.
(You can do this without pissing off management if you do it carefully... Turn off all power first, etc.)

If these are the "Super Mega" racks, et. al. that were wired up by CFS like I think they are, there are wiring F-ups all over in there! Unbalanced lines going right near and parallel to power mains cords. Shields are grounded on both ends. There are poor connections and cold solder joints all through them! I have spend hours fixing those beasts!

Posted by Aaron Garman (Member # 1653) on 07-26-2003, 02:35 AM:

This is all starting to make more sense to me now guys. I think my next chance to check this out is on Sunday night, so I'll try to report back then. I think I'm going to print parts of this thread to show our manager that night. You all mention groundloop hum...what exactly does that mean? I've always heard of it, but never knew exactly what it really is or how it can happen. Also, any links on how wiring these racks works and what has to go to what. I know audio pretty well, but only on the homefront. I'm still a newbie to commercial stuff. Thanks for the help again.

AJG

Posted by Michael Schaffer (Member # 1204) on 07-26-2003, 07:10 AM:

quote:
Good idea!

It wasn`t my idea. I called the technical support at UltraStereo.

Posted by Randy Stankey (Member # 64) on 07-27-2003, 09:09 AM:

Yeah, yeah... but you though of posting it!

Posted by Frank Angel (Member # 248) on 07-27-2003, 09:33 AM:

Years ago one of the techs who was trained by the RCA Theatre Sound Service told me that they taught the RCA Cut-and-Solder method of troubleshooting those elusive groundloops. What you do is, keep the system on and listening to the hum, you cut the shield. If the hum decreases, you leave the shield off. If the hum increases, you solder it back on. Repeat until you run into overtime. Pretty scientific, eh? [Roll Eyes]

Eventhough you may think you understand the theory about how 60Hz hum is introduced in sound system wiring, when you come into facility, especially older ones, you are faced with years of different engineers and techs following the beat of their own private drummer, many times resulting in such a hodgepodge of techniques and no discernable, consistant protocol. It then becomes a guessing game since you have no idea what the guys before them did or how the mains electrical system has been modified or added to.

When I first came into the recording studio attached to our theatre, I was able to put a meter lead on a ground pin in an electrical outlet on one side of the room, the other lead on the chassis of the main equipment rack -- I read +17v! The three phase legs of the service had become so unbalanced over the years that no matter what you did in the room, you were fighting huge amperage discrepancies across the legs.

Any idea what kind of hum +17v above ground represents if it gets into the audio circuit? Sensuround, my friends -- then speaker and amp failure! Try blocking THAT much unbalanced energy with an electronic balanced input.

Frank

Posted by Steve Guttag (Member # 268) on 07-27-2003, 02:49 PM:

Transformers....lots of transformers [Wink]

Grounding methods are not understood as well as they need to be my most technicians.

One suggestion I see many times is the equipment to rack bond...if putting "star-washers" or other schemes "fixes" the ground loop hum...then you really haven't fixed it...the problem lies elsewhere and you just minimized it by using the rack as your common "wire." Don't get me wrong, the rack MUST be grounded for safety and RF reasons...not to mention that it must not contribute to the ground loop.

Grounding is actually a simple concept at heart but it can be rather elusive. The simple rule is...every piece of equipment MUST be grounded at the exact same ground potential such that ground between each piece of equipment has a zero resistance.

Believe it or not, lifting the shield at one end is also a cover up...in a perfectly grounded system, both shields should be tied to minimize RF interference. The problem is often that perfect grounding concept. It is difficult to impossible to achieve in a typical theatre environment. A good ground has to be designed in by a competent engineer.

If you have unbalanced equipment (older Dolby, CP-65 and prior, USL JS series...etc.) then you have to be even more deligent in your grounding. For unbalanced equipment uses the "return" often at ground potential. If ANY piece of unbalanced equipment grounds their "low" or return side then EVERY piece of equipment must also ground their return side to the EXACT same ground. Otherwise you will get current flow on the returns and a ground loop is formed.

Troubleshooting Hums and groundloops are like any other troubleshooting...be methodical and logical.

You hear the hum in the speaker work your way back...starting with the wire...believe it or not a speaker can make noise without the amplifer...it just needs that wire to get some induced noise.

From there...the amplifiers and then on back to the processor and eventually the soundhead(s). Once you isolate at which section the hum starts (be it in the form of just a noisy piece of equipment or electrical ground loop type hums) then you can delve into what is the cause.

Steve

Posted by Bruce Hansen (Member # 281) on 07-27-2003, 02:52 PM:

There is a strange notion that you should put everything on the same phase (leg) to keep hum out of the system. This is actualy the way to make sure you DO have hum. Balanceing the legs is the best thing to do.

Posted by Jack Ondracek (Member # 1466) on 07-27-2003, 03:10 PM:

quote:
There is a strange notion that you should put everything on the same phase (leg) to keep hum out of the system. This is actualy the way to make sure you DO have hum. Balanceing the legs is the best thing to do.

Some of that may have come from installations that had feed lines of different lengths.

We once had a studio in a radio station that had horrendous RF problems. All of the normal fixes failed rather miserably. It wasn't until someone discovered that two of the outlets (within 4 feet of each other) had separate feeds to the panel, at the other end of the building, taking different routes to get there.

Needless to say, the ground potential between the two lines was NOT zero!

Posted by Jim Alexander (Member # 226) on 07-27-2003, 06:38 PM:

Quote Aaron:
You all mention groundloop hum...what exactly does that mean? I've always heard of it, but never knew exactly what it really is or how it can happen. Also, any links on how wiring these racks works and what has to go to what. I know audio pretty well, but only on the homefront. I'm still a newbie to commercial stuff.

In essance, a ground loop is an antenna. Since the most common type of RF in most buildings is 60Hz, which is radiated from every electical wire and system, it is the one that is most likely to be picked up. By grounding a shield at both ends, the ground becomes a ground plane and the shield becomes the antenna, which in turn induces whatever it picks up onto the audio lines. Low level audio is more suseptable to this than high level, as well a unbalanced over balanced, but once in the system, it can be a real pain. Proper shield grounding should look like a tree, and idealy each shield is grounded to a fresh ground (not one derived from component to component). Having said all this, the ground must be capable of handling the grounding load...a 12 gauge wire will not handle the grounding requirements for a complete booth. Understanding this and elimintaing it will go a long way to "quieting" your audio.

Another consideration is the placement of your audio lines. Don't run low level with high level...the sheilds are good, but not always that good. And never...NEVER EVER run any audio lines with power cables...60hz and 120/240 will over power audio at 30mV or 1.5V.

Having said all this, from listening to your posts as well as others, your problem may or may not be a shield problem. From your comments, when the processor if off, the hum is gone. If it was a sheild problem, between the processor and the amp, this would not have eliminated it...it could be induced on the optical/digital pickup side, but not between the processor and amp. Sounds to me like a "active" hum which could be ripple in the power supply or a bad output card...but I'd say the problem is in the processor/power supply....

Posted by Steve Guttag (Member # 268) on 07-28-2003, 07:54 AM:

A ground loop is in no way shape or form an antenna. It is as the name implies an electrical loop formed by "grounds" of different potential. It has nothing to do with an induced hum.

If the grounds of a system are not of the same potential then current flow will result (on the ground wires themselves) and the hum is the by product.

Now there are other noise (including those that take the form of hums) that can be induced but they are not groundloops.

Steve

Posted by Jim Alexander (Member # 226) on 07-29-2003, 09:30 AM:

Well Duh! What do you think an antenna is. An chunk of wire attached to a capacitive/inductive tank or filter. The length of the wire or antenna is matched to the center frequency of choice and the tank selects the frequency you want. All you you have described is the tank function...inductive capacitive loop. Mine was the simplisitc explaination, meant to make understanding a little easier.

And you are right, their are may other forms of hum, just as I said, the problem here sounds like an hum coming from an active component and not a ground loop.

Posted by Tim Reed (Member # 137) on 07-29-2003, 12:27 PM:

Jim's right. I had a grounding problem in a theatre that was causing it to pick up a local radio station. Fixed the bad ground, no more receiver.

Posted by Steve Guttag (Member # 268) on 07-29-2003, 09:34 PM:

Tim,

A bad ground (overall), is also not the same as a ground loop and yes, a bad ground can allow your system to act as an antenna...but again, different than a ground loop.

Ground, for audio takes on several purposes. One is for safety...most professional equipment is grounded via the ground pin on the power plug. In a well designed piece of equipment this will ensure that the frame of the equipment is at ground potential and often now also provides RFI/EMI protection (either emitting out or receiving in).

Ground also allows us to effectively use shields since the "shield" is tied to ground and drains away induced noise.

Ground is also a reference. While it is not necessary that ground be the reference in an audio system, it often is and as such is often the reason a ground loop can come up. That is, if both pieces of equipment use ground as its reference but if both pieces don't connect to the same ground then a potential difference can exist between each piece of equipment's ground reference.

Addionally, if ground is used as the reference, any noise impressed onto the ground buss can show up in the sound (or video) system as well.

Steve

Posted by Manny Knowles (Member # 1171) on 07-30-2003, 10:10 AM:

I'm just curious if Aaron was able to troubleshoot this yet. We've taken bets on the cause here and I'd really like to collect my earnings! [Wink]

Seriously, though. One needs closure.

Posted by Tim Reed (Member # 137) on 07-30-2003, 10:20 AM:

quote:
Tim,

A bad ground (overall), is also not the same as a ground loop

I never said it was. I was talking about Jim being right about the antenna.

de, KJ5KX

Posted by Darryl Spicer (Member # 711) on 07-30-2003, 05:44 PM:

Something just came to mind that I don't think we mentioned.

Is the hum present no matter what you put the format card in. Does it do it in nsync, mono, stereo, and digital. Does it do it with the format card removed.

If the hum is only present in the stereo and mono selections it could be a solar cell wiring issue. If you are using a Jax light setup the line amp could be introducing the hum into the system. Could be a loose ground on the solar cell imputs. I'm affraid to say it could be many things. Sound problems can turn a man grey and cause him to loose a lot of hair.

Posted by Aaron Garman (Member # 1653) on 07-30-2003, 07:21 PM:

Hello all. Just got in from work, and I tried some stuff today. First of all, I did the old switcheroo with another power supply. This did not solve the problem. I guess the plot thickens. I'm going back in tonight to see the film in that house and then I work tomorrow morning. Any more advice guys? Thanks for all the help.

EDIT: I'll see if it hums tonight in DIGITAL Darryl. I didn't even think of checking that this afternoon, as I was busy enough as it is.

AJG

Posted by Jim Alexander (Member # 226) on 07-30-2003, 08:49 PM:

Quote Steve Guttag:

A bad ground (overall), is also not the same as
a ground loop and yes, a bad ground can allow your system
to act as an antenna...but again, different than a ground
loop.

Ok, now we are talking apples and oranges.... A bad ground, something like a "floating Ground" will normally follow the potential of the line signal that it is attached to. In which case the audio signals will resultantly follow, which equates to hum at the speaker...you are right it is different, but not as you elude to.

Quote Steve:

Ground, for audio takes on several purposes. One is for
safety...most professional equipment is grounded via the
ground pin on the power plug. In a well designed piece of
equipment this will ensure that the frame of the
equipment is at ground potential and often now also
provides RFI/EMI protection (either emitting out or
receiving in).

Ok, let's start by separating this discussion. Sheilds and grounds. Grounds, as you state have many purposes. Safetly, potential reference, etc... Sheilds are a different matter. They serve one purpose, and one purpose only, and that is to electrically isolate the audio signal lines from any extrenuous electrical noise. They originate from grounds and cover certain wires known to be sensitive to interference. Some call it EMI protection, others call it shielding, but the end result is it prevents induction of electrical noise onto the signal lines that may be sensitive... like audio.

Contrary to what you've said, ground loops do not need equipment at different potentials to form. A prime example of this is aircraft wiring. A great deal of engineering goes into ensuring equipment is, not only grounded, but grounded to the exact same reference and potential. However, should a loop be formed by grounding both ends of the shields, EMI interference will result. And, in the cases on aircraft, this can manifest its self is a wide range of problems. Radar systems that will not receive returns. Audio intercom systems that receive VHF transmissions where no radio is connected to them (I even had one aircraft that received the local AM radio station on the intercom, even though there was no AM receiver on the aircraft!). Engine monitor displays that fluctuate whenever a Transmitter is keyed. Sheilding, if not done properly will cause problems...EMI (Electro-Magnetic Interference) and ground loops is a complex theory that is difficult to understand at the best of times. The easiest solution to explaining it to most non-electronic, or people who have not been trained in EMI prvention, is to use the antenna example. People can understand that. They have a difficult time comprehending an indepth EMI discussion.

Posted by Gordon McLeod (Member # 33) on 07-31-2003, 10:09 PM:

I tend to avoid the antenna explanation as it is also misleading
A ground loop is not an induced noise that is similar to antenna or magnetic coupling
Star Grounding of sensitive equipment is the best solution

Posted by Steve Guttag (Member # 268) on 08-01-2003, 11:29 PM:

Somehow, I don't think I'm communicating my thoughts very well...especially as Gord seems to be agreeing with me [Wink]

Suffice to say, I wouldn't use the antenna analogy in ground loop situation and clearly others would and had success with that....I can live with that.

Steve

Posted by Gordon McLeod (Member # 33) on 08-02-2003, 10:17 AM:

Steve Brad says I am allowed to agree with you once a month [Big Grin]

Posted by Steve Guttag (Member # 268) on 08-03-2003, 01:38 AM:

Hmmm and you agreed with me on the last day of last month...I wonder what it will be this month...anticipation... [Razz]

Steve

Posted by Daryl C. W. O'Shea (Member # 1303) on 08-04-2003, 06:05 AM:

[gord]

and

disagree, never!

Posted by Clint Koch (Member # 1179) on 08-07-2003, 06:45 PM:

Was this ever fixed?

Posted by Aaron Garman (Member # 1653) on 08-07-2003, 07:56 PM:

I have yet to fix it. I've told two managers about it, and I do not believe they have taken a look at it as of yet either. I've reported all my problems to them, what I've tried, and what it could be. I guess all I can do is wait for them or our tech to come in. I'll keep you all posted if it is fixed. Thanks for all the help guys.

AJG

Posted by Aaron Garman (Member # 1653) on 02-24-2004, 11:49 PM:

After a long while, I've ressurected this thread because the problem is more or less fixed. I finally got a manager to help me change the format card...joila! Of course, the hum is now in the auditorium we swapped cards with, but we at least know what the problem is. Our tech is supposed to come in this week so now we only need to get a new format card. But I did have some questions. The bad card was in a large theatre (386) and the good one came from a smaller one (roughly 150). Now, we ran some trailers in both and the bass does sound louder and maybe a tad hot, but it's good for now. Is it ok to leave it this way? Also, is there anything else that may change because of swapping out the cards? It's great timing too: we're running The Passion in this big house starting tomorrow. I want to thank all of you for your help in this matter. I'll still keep this up to date if anything changes.

AJG

Posted by Brad Miller (Member # 2) on 02-25-2004, 04:23 AM:

Just one thing...make sure to put a note on the cards and processors so when your tech comes in he can put the good card BACK where it belongs and calibrate your new card in the house that originally had the bad one.

Posted by Gordon McLeod (Member # 33) on 02-25-2004, 09:47 AM:

The sub level is set on the format card so that is why when you swapped it the levels changed