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New Rel Carbon Special Sub “Roars” when there is no signal!

I’ve been breaking in my new Rel Carbon special subs (I have a pair) and one of them started having an issue after about 12 hours of playing them (quite loud).

Just recently the left sub makes an absolute roaring sound when the music signal stops, or when I turn the volume all the way down.  It starts as a quiet rumble but VERY quickly builds to an absolute massive roar.  Was worried about damage but it seems fine provided a music signal is playing.  The issue did not happen until just recently. Now, when I simply turn on the sub, even with the Amp in standby mode, the roar starts building and I have to shut off the sub really, really quickly.

I have my Rel’s connected to my Gryphon Diablo 300, using Rel Bassline Blue high level cables, using Rel’s directions for connecting a balanced differential amp which I’m told the Diablo 300 is.  I have each sub’s high level cable connected to the amp with each cable’s yellow and red lead connected to the red speaker output, and both black ground leads connected to my Diablo 300’s ground terminal.

There is one thing different about each sub right now - the sub without any issue is connected to the wall to a dedicated 20A circuit.  The sub that just recently developed the issue is connected to a shared 15A household outlet - temporary until I acquire longer power cords. I have half a mind to plug the “working” sub to the shared household AC circuit to see if the problem is limited to that line but I’m a bit scared of damaging something.

My Diablo 300 amp is connected to a Torus RM 20 that is plugged into another dedicated 20A outlet….

Any guidance would be appreciated!

 

 

 

nyev

Showing 4 responses by holmz

holmz's avatar
holmz
2,328 posts
 

Send that one back or contact the MFR

holmz's avatar
holmz
2,328 posts
 

When sliding the sub forward or backwards the problem goes away. When I leave the sub in place and move the power and signal cables away from other wiring, then the problem remains. It’s definitely something that happens when the sub is in that exact spot, AND the speakon signal cable is connected, AND there is no signal /music playing. Weirdly, it even happens when the amp is turned off and unplugged. But disconnect the speakon signal cable and no issue when powering on! Very weird problem. But nothing wrong with the subs. I’m going to buy a roll of EMI shielding material to experiment with. It’s not too expensive, and maybe I can try multiple layers if needed. The cover with a small bit of carpet or rug for aesthetics, once the issue is resolved.

I would swaping the left and right SpeakOn cable, and also the power cables.

holmz's avatar
holmz
2,328 posts
 

I do have a terrible amount of coiled power cords (high end Audioquest) behind my system that I think is also a possible culprit.

Well the speaker wire carry a lot of current, and so does the sub.
Any magnetic field that is coupled into the speaker wire or IC would generate a 60Hz signal.
I suppose a coil of wire is a great way to make an electrical coil. 

I’ll quote myself…

I would swaping the left and right SpeakOn cable, and also the power cables.

holmz's avatar
holmz
2,328 posts
 

Forgive me if I missed something but,

As @sryeager noted you may have a ground loop between the two RELs.  Plugging them both to the 20A line with an extension cord would be an easy check.  An acoustic  feedback loop with the amp unplugged is a non starter. Two REL inputs tied to the speaker terminals will not drive a speaker either.  A ground loop can, and the pure 60Hz tone suggests that.  A weak or missing ground can do strange things.  My 2 cents.

^Nice^ - I think you could be onto something, but the ever increasing loudness is still puzzling.

 

I believe that the speaker cables are also in the loop, with the SpeakOn hooked up to them.
So the OP might need both of the subs “and the amp” on the same power strip.

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