Diagnosis...Ground Humm (need help!)

[Bravo(1)]

In my recording setup I'm noticing what I believe is a "ground humm." I say this because this is a relatively new term for me but by judging the deep droning sound I'm getting, it sounds like an applicable description.

My current setup is as follow...

I run my sampling/listening sources (CD player and Trurntable) through a relatively cheap 2 channel Gemini GMX DJ mixer. From there I run my DJ mixer out put in to my channels on my Yamaha MG mixer. Also going into the Yamaha is my ASR X Pro sampler, and output from my PC sound card. I'm running 2outputs from the Yamaha, one into my Tascan US-428 recording interface and another into my powered speaker amp.

After some tooling around I've noticed I don't get the "noise" from the imput from the ASR, but only from my sources that are fed through the DJ mixer.

Now I'm wondering what could be the cause of my noise? Could it be the cables (I'm using all unbalanced), the DJ mixer (it's in good condition but very basic), or is it my level settings (at what stage in my monitor mix should I be adjusting gain, faders, amp level and such)???

As stated previously I'm not sure it's ground humm but I can only describe it as a deep droning, swelling sound.

Thank so much for the assistance

PS. my turntable is grounded to the DJ mixer, which I do not believe has a preamp.


Bravo1

 

[CubaseRox]

After some tooling around I've noticed I don't get the "noise" from the imput from the ASR, but only from my sources that are fed through the DJ mixer.

The mixer itself may be bad and/or have a poor ground. Try to swap mixers and see if that helps.

 

[Bravo(1)]

Originally posted by CubaseRox

The mixer itself may be bad and/or have a poor ground. Try to swap mixers and see if that helps.

Not being familiar with grounding... At where or what would a mixer generally be grounded to aside form the RCA ground cable from the table to the mixer?

Does chaining the 2 mixers in this fashion generally set myself up for potential problems like I'm having?


thx

 

[CubaseRox]

Not being familiar with grounding... At where or what would a mixer generally be grounded to aside form the RCA ground cable from the table to the mixer?

The RCA from the TT is not a ground, that little 22AWG wire is. Aside from that the mixer still isnt grounded. The mixer gets its ground via the electrical cord, when its plugged in. Usually in a 2 prong plug, one prong acts as the ground (neutral wire). But some mixers may have the 3 prong plugs where as the 3rd prong (also called the U ground) acts as a secondary ground. But like I said before the mixer could be causing the problem and may not be fixable.

Does chaining the 2 mixers in this fashion generally set myself up for potential problems like I'm having?

Why do you need all these DJ mixers? Do you have more sources to plug in? I would suggest getting a small 12 channel recording mixer. it would sound alot better too.

But to answer your question it may add to the problem. If one mixer is "humming" it might still be present in the signal.

Hope this helps.

 

[Bravo(1)]

Originally posted by CubaseRox
Why do you need all these DJ mixers? Do you have more sources to plug in? I would suggest getting a small 12 channel recording mixer. it would sound alot better too.

I'm sorry. To clarify there's only one DJ mixer in my set up (Gemini), The Yamaha to which im running my DJ Mixer output into for monitoring is a 10 channel recording mixer.

my only sampling sources are (1) cd player, and (1) turntable.

 

[Ebbiguise555]

You need to get them all plugged into seperate wall outlets in the room...If you have them all running into one wall outlet and chained together then that could be a problem....Also keeping the power supplies (the boxes they might have on one end) to your keyboards/mixers in certain positiona will eliminate it, and/or cause this kind of hum....I'd start with getting a few extensions and splitting up to where you are plugging in your gear in the room, which is probably ur problem-




555

 

[CubaseRox]

You need to get them all plugged into seperate wall outlets in the room...If you have them all running into one wall outlet and chained together then that could be a problem....

Yeah but if all the outlets are on the same circuit (which is what they most likely are) that wont do anything.

Even if they are on different circuits they would have to be split between the 2 phases. You would have to open the panel and check for that. And still that might not make a difference.

In his first post he said: "I don't get the "noise" from the imput from the ASR, but only from my sources that are fed through the DJ mixer".

So I would assume its the mixer alone that is causing the humming. Unless he has the gains turned all the way up on something.

 

[Bravo(1)]

Originally posted by CubaseRox So I would assume its the mixer alone that is causing the humming. Unless he has the gains turned all the way up on something. [/B]

Ok, so what would be and ideal gain/level setting structure in my recording/monitoring setup? Assuming I'm connecting 3 in 3 stages (DJ mixer==>Analog recording mixer==>Recording interface mixer)?

ie. At what points in my chain should the gain or level be peaked or minimized? Or better worded...is it more ideal to have a low gain and a high fader level or vice versa? Should I be trying to have levels and gains up closer to the source as possible, using little gain at my recording or sampling stage or vice versa? Is there a blueprint for for this theory or is it just a matter of turning and tweaking untill i get it right?


FYI, the noise is relative the my level settings. Meaning if I turn a level down the noise goes away. Obviously not allowing me to monitor or record at high levels. Is this as well consistant with ground humm?

 

[CubaseRox]

There are no set guidelines as to what each fader or volume knob should be at. A rule of thumb is to not have them all cranked up to their absolute peak either.

If you have a bunch of knobs/faders that need to be adjusted, then turn all of them down and start pulling them up one by one. Dont peak each one, keep them up high enough to mask the noise floor but low enough to not hear the unwanted noise.

Your recording signal doesnt have to be directly on the 0, it can be slightly lower. You can raise that volume curve during mixing and mastering. The idea is to get a good clean recording to start with and then work off of that.