Noisy Driverack PA (or how I solved the problem)
Over the past years of doing this I have seen a small number of complaints regarding the DRPA and noise...Not anything terrible but a light hiss. I recently got a set of industry standard Anchor Extreme powered speakers, and I built a set of the DIY subs I supplied the plans for in the FAQ section. I intend to use these in a rental setup...during the testing phase I was using an el-cheapo Behringer mixer (UBFX16) and needed a cable to go from the mixer to the Anchors...now, they(the Anchor's) have MULTIPLE inputs including line, mic, CD and more, each has a level control. The line input, as you may suspect has a 1/4" input.. now, normally I wouldn't have even thought twice about using a mic cable from the mixers XLR output to the Anchors XLR inputs which have a switch for mic or line level applications. In my hast to "get to the good stuff" I was one mic cable short, but had an XLR to 1/4" balanced (TRS) cable. So I implemented it! (this was a GOOD quality Belden/Neutrik hand made by me cable) ( I have BILLIONS of cables!!! 
)
As I went about the setup process on the brand spanking new DRPA+ I was drawn to the Anchors sitting atop the new subs...there was a definite HISSSSSSS coming from them. Ok, so here is the issue right in front of me...so I tried everything.. turning down the gain to zero on the Anchors did NOTHING to quench the hiss.. the ONLY thing that made a difference was unplugging the cable from the DRPA+... either end, didn't matter...DRPA end or speaker.. hiss went away. "Well, this ain't good!" I thought...well ok, make the journey all the way to the upstairs studio, or out to the trailers for another XLR cable. (just being lazy here :roll: but if I hadn't I wouldn't have been led to this post) Well, with a good quality (there are MANY grades of cable and I am NOT a proponent of the super high end "audiophile grade" cables, just a cable with good shielding, and quality ends like Beldin/Neutrik or even Horizon...but not those Chinese 10 twenty footers for $30 jobs ) cable plugged into the mixers XLR outputs, and the XLR inputs on the Anchors, properly set to line level.. the hiss was GONE! I could turn the Anchors gain up fully and even with no output from the mixer, and the mixers master faders @ unity, there was no increase to the noise floor of the speakers (which ain't much).
Ok, so we have established that if there is a miss match of cables and input output impedance there can be a hiss. So, make sure you have quality cables, and that you are using the correct input/output configuration.
Gadget
)As I went about the setup process on the brand spanking new DRPA+ I was drawn to the Anchors sitting atop the new subs...there was a definite HISSSSSSS coming from them. Ok, so here is the issue right in front of me...so I tried everything.. turning down the gain to zero on the Anchors did NOTHING to quench the hiss.. the ONLY thing that made a difference was unplugging the cable from the DRPA+... either end, didn't matter...DRPA end or speaker.. hiss went away. "Well, this ain't good!" I thought...well ok, make the journey all the way to the upstairs studio, or out to the trailers for another XLR cable. (just being lazy here :roll: but if I hadn't I wouldn't have been led to this post) Well, with a good quality (there are MANY grades of cable and I am NOT a proponent of the super high end "audiophile grade" cables, just a cable with good shielding, and quality ends like Beldin/Neutrik or even Horizon...but not those Chinese 10 twenty footers for $30 jobs ) cable plugged into the mixers XLR outputs, and the XLR inputs on the Anchors, properly set to line level.. the hiss was GONE! I could turn the Anchors gain up fully and even with no output from the mixer, and the mixers master faders @ unity, there was no increase to the noise floor of the speakers (which ain't much).
Ok, so we have established that if there is a miss match of cables and input output impedance there can be a hiss. So, make sure you have quality cables, and that you are using the correct input/output configuration.
Gadget
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