Troubleshooting a popping sound?

[wheresgrant3]

I play keys in a local cover band and I have a pretty self contained rig. A few weeks ago a mysterious "popping" sound started coming through my rig and I'm trying to come up with reasons why. The problem is that a lot of my gear resides in our trailer so I only have time to deal with it when I'm on stage setting up for soundcheck.

 

 

I have several synths mixed into a small sub mixer (Yamaha MG10/2) I run the ST outs to a stereo DI and then to our main PA board. The c/r out to two Yorkville monitors at my feet. It's great b/c I can control my own mix through out the show. Last month I noticed a loud "popping sound" every 20-30 seconds coming from my monitors. I went FOH and the sound was there too. Of course amplified it sounds horrible like someone is tripping a breaker. I can tell through the LED on my mixer that the sound is coming from one of my keys or a cable. Everytime the "pop" occures my LED redlines.

 

My guess it could be a number of differn't things.

 

-My new Korg Extreme- Well new/used. I added this to my setup a month ago... it coincided with the popping noise.

-A new/used Yorkville keyboard monitor I added around the same time. Bought it thru Ebay and the amp seemed to work fine. Keep in mind that it receives a signal from the mixer thru a balanced input in front. Not sure how or why it would send a return "pop".

-The obligatory Bad Cable- I built a small snake using two dual input TRS cable and some electrical tape. It's been very handy to roll that out instead of a mess of cable at my feet. It would suck if one of the cables went bad. Then again it's HOSA so anything is possible.

-Dropped the mini mixer- About 2 months ago it feel from it's velcroed case during tear down and came crashing down to the floor. It seemed to work fine for a month after that so this is on the back burner for me.

 

I know a complete setup is the only way to eliminate/troubleshoot this mess. Just wondering if anyone would have a idea based on past experience what would cause this "pop" to occur.

[where02190]

 

It's great b/c I can control my own mix through out the show.

 

 

Great for you, potentially disasterous for the FOH mix. What you hear onstage is not at all what the audience wants or needs in most cases.

 

AFA your problem, disconnect everything, and starting from the DI's, connect everything one at a time until the problem exists. The last thing you plugged in is the source of the problem.

[JohnnyGraphic]

Since the pop is showing up on the mixer, it could be the keyboard or the cables. I'm not a big fan of Hosa. I have a few. Dragged one out last week (barely used) and the left side had a short in it.

 

I would first check if the pop occurs on a specific channel(s) (For example-the channels that the Korg is hooked up to). Solo/PFL the particular channel & see if it happens. If not, then go to the next channel(s). This could be done w/o your signal going to the amp or the FOH.

 

Being methodical really helps here.

 

If nothing, then start moving the cables around. If you get the pop there, then in all likelihood, it is the cable. (If you have a cable tester, then this is a good time to whip it out).

 

In any event, before your next gig, I would stop by and pick up some good quality cables with good quality connectors.

 

If you still don't have any popping, disconnect everything and see if the popping happens within the mixer.

 

If so, time to either repair or replace.

 

My only other thought is that it might be electrical-perhaps an AC power supply or something of that nature.

 

That's my 2 cents. Hope you find it. Troubleshooting stuff is very very frustrating!!!

 

Johnny

[wheresgrant3]

Originally posted by where02190 Great for you, potentially disasterous for the FOH mix. What you hear onstage is not at all what the audience wants or needs in most cases.

 

True...talking to a soundguy... I'm your worst nightmare... but 90% of the rooms we play we provide the sound. The 10% of the rooms with sound the soundguys are usually {censored}e.

 

Trust me when I say I'm very conservative about my mix. I setup usually in an "L" right next to our FOH stack, with my left ear tilted toward the FOH. I usually keep my monitors very low, and listen for the bleed. We tilt our FOH toward the center , so if I can hear myself clearly through the FOH I know it's too high. Organs, Brass... anything with a very high end that cuts through the mix I pull down.... anything that is a little "brown" in texture (pads, synthy, rez patches... many pre-recorded samples) I leave at set levels. After over 100 gigs, monitoring our FOH from stage is second nature to my playing. One of our 'roadies' has a great ear and will sit in the audience and guide through most of the night with a thumbs up/down or an "A-OK" sign. Since we get many compliments on our mix I assume to this point it hasn't been a problem. Prior to me handling it this way all I ever heard was "Turn up the keyboards... we see him playing and hear nothing".

 

Believe me .... every once in a while I'll forget to pull down a brass stab and the moment I do, I'll see a pained expression on someone in the audience. OOPS!

[wheresgrant3]

 

Originally posted by JohnnyGraphic Since the pop is showing up on the mixer, it could be the keyboard or the cables. I'm not a big fan of Hosa. I have a few. Dragged one out last week (barely used) and the left side had a short in it. I would first check if the pop occurs on a specific channel(s) (For example-the channels that the Korg is hooked up to). Solo/PFL the particular channel & see if it happens. If not, then go to the next channel(s). This could be done w/o your signal going to the amp or the FOH. Being methodical really helps here. If nothing, then start moving the cables around. If you get the pop there, then in all likelihood, it is the cable. (If you have a cable tester, then this is a good time to whip it out). In any event, before your next gig, I would stop by and pick up some good quality cables with good quality connectors. If you still don't have any popping, disconnect everything and see if the popping happens within the mixer. If so, time to either repair or replace. My only other thought is that it might be electrical-perhaps an AC power supply or something of that nature. That's my 2 cents. Hope you find it. Troubleshooting stuff is very very frustrating!!! Johnny

 

 

Hmmmm It could be the power supply to the mixer. It doesn't seem like a crackle or "pop" from a bad cable. It seems more like a pop from a bad power source. Like I said... my LED will spike into the red from dead silence. Connected to the FOH it sounds like a "Thud" like someone connected an input jack. It doesn't seem to occure when I'm sending sound... or maybe the popping is drowned out by the mix. It happens when all cables are idle as well.

[JohnnyGraphic]

 

Originally posted by wheresgrant3 Hmmmm It could be the power supply to the mixer. It doesn't seem like a crackle or "pop" from a bad cable. It seems more like a pop from a bad power source. Like I said... my LED will spike into the red from dead silence. Connected to the FOH it sounds like a "Thud" like someone connected an input jack. It doesn't seem to occure when I'm sending sound... or maybe the popping is drowned out by the mix. It happens when all cables are idle as well.

 

 

I would try to isolate which keyboard it is that is causing this. Does it occur if you are listening on headphones with a particular keyboard? If not, then, it could be the mixer or the mixers power supply(???). Just guessing here.

 

Also, does the spike happen on a particular channel too or just the main output of the mixer?

 

Another thing, just something I noticed, are you supposed to have a DI from the output of a mixer to another mixer? (I don't really know about DI's). I always thought that you use those to connect a keyboard to a mixer...???

 

Johnny

[wheresgrant3]

 

Originally posted by JohnnyGraphic Another thing, just something I noticed, are you supposed to have a DI from the output of a mixer to another mixer? (I don't really know about DI's). I always thought that you use those to connect a keyboard to a mixer...??? Johnny

 

 

Good question. Even though my mini mixer sends a balanced signal to the main we still had tons o' buzz. FOH I started using a DI for ground lift. I would prefer not to use the DI or to find a decent cable with TRS jacks on one end and male XLR on the other 30" or longer but this is what I came up with for the short .,.. and stuck with it b/c it worked great!

 

If anyone has a better solution... please send it my way.

[JohnnyGraphic]

 

Originally posted by wheresgrant3 Good question. Even though my mini mixer sends a balanced signal to the main we still had tons o' buzz. FOH I started using a DI for ground lift. I would prefer not to use the DI or to find a decent cable with TRS jacks on one end and male XLR on the other 30" or longer but this is what I came up with for the short .,.. and stuck with it b/c it worked great! If anyone has a better solution... please send it my way.

 

 

I'm sure others would know more about this sort of thing than me, but, shouldn't the DI go in between the keyboard and the mixer? Also, is your DI run off of a battery or AC? If it is battery driven, could your battery be low or dead?

 

Also, in any case, the line from the mixer output should be balanced cable no matter what-TRS or XLR.

 

Johnny

[where02190]

If you are connecting a balanced line level source to a balanced line input, you don't need a DI, however you may need an isolation xformer if there is issues with noise/hum.

[agedhorse]

A DI (transformer isolated of course) may be just fine connecting to a mic input of another console since the voltage stepdown can reduce the input signal to a better level for the console input BUT if you have a pro console then a 1:1 isolation transformer is a better solution IMO.