hum developed ? any tips?

premier1

Ok here is the deal, when i run my subs aux fed there is a hum that has started to happen when the atenuator is fully turned up on my amp, once the band is playing its not heard obviously, I switched it back to running the subs from the drpa and no hum at all with the volume turned up, what could be going on here? I am feeding the subs from a subgroup out when i use aux fed, why is there a hum one way and not the other? do I need a di box between the amp and mixer to solve this? I just cant figure it out, thanks

Dra

How would you compare the volume of the subs in either set-up?

DRA

Gadget

So are you feeding the subs unbalanced output from the aux or 1/4" TRS all the way? Even TRS will have a significantly lower output potential, on most mixers, than an XLR output.

I run mono FOH and Aux fed subs through the same DRPA+ every week, and even TRS out fm mixer to XLR in to DRPA+ I typically need to add at least 6-10dB of gain on the aux master to comp with the mains...
G

Gadget

So, after having those Impulse speakers for a while now, how would you characteristic them? Are you still happy with them? Have you had any problems with them? How much EQ do you typically need to make them sound the way you want?

How is the HF projection at distance? Off axis response..is it spotty across the band ? OR pretty even out to say 30 or 45 degrees?
G

premier1

Hi guys thanks, Ok first on the peavey impulse, in my opinion and a humble one at that, I think they are fantastic, never once had a complaint at any venue we play that the sound wasnt pristene! They have plenty power, we are a loud band with hi energy and the vocals are cutting though now no problem, there is plenty of headroom also as I only have them turned up a little past half and thats plenty, the bass responce is very respectable for a 12 nice and tight ansd punchy. The highs are crystal clear and carry well from feedback I get from patrons and fellow musicians, many of them cant understand how two 12s is all were using! there good, as far as eq, I set the dr eqat flat with the measurment mic and I have not touched it since ! the only thing I tweak her and there is the PEQ for certain rooms here and there but honestly thats very far and few between, it sounds great as is with a flat curve on the DR. as for off axis and im assuming you mean off to the sides, it seems ok again, Im playing the drums and never get to walk out front and around to hear us all playing but fellow bands have commented on how much they like them, the coverage is simply fine!

Since i aux feed my subs, during breaks I play music from the board and only those peaveys are working, they sound awesome! Im very happy as are my bandmates, these are well worth the money and they sound great right out of the box, peavey hit a homerun with these, hope this helps!
now back to the subs, I did notice I hqave to trun up the bandpass on the xti to get a good volume and with that comes the hum, cvutting 40hz and below help but its still there, and i wish i could use xlr but on the board the sux and subgroup outs are only 1/4 inch, i guess I can fool with the dsp more on the xti to try and rid them of most of the hum. thanks guys!

Gadget

Are you using balanced 1/4"?

Are your amps on the same electrical circuit as the mixer/drpa?
G

Dennis

premier1 wrote:

when i run my subs aux fed there is a hum that has started to happen when the atenuator is fully turned up on my amp

What changed with your system that could have potentially caused a hum? Was any new equipment added? A new or different direct box for bass or keys? New gates, comps or anything else that inserts into your mixer (specifically unbalanced inserts)? Disconnect everything from the mixer except the aux fed sub. Does it still hum? If not, reconnect everything one piece at a time and check to see when hum returns.

Are there any ground pins broken off of extention cords or equipment power cables?

If you can run balanced aux fed subs, you could try lifting pin 1 on one end of the cable that runs from the mixer to the next stage in your chain (EQ, DriveRack, Amplifier. You can try lifting pin 1 between each stage if you have more than one). This, however does not address the cause of the original problem.

Dennis

premier1

Ok my bad, the cause of the hum after digging deeper was in fact an eq issue, I simply had far to much 42hz jacked up on the dsp of the crown xti, once I lowered that it was fine. Sorry for taking up time!