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

@holmz , thanks and yes I did try swapping the speakon cables, with no change.  Haven’t swapped the power cables though, will try that next.  Not expecting any change, but I’ll let you know if there is.

So I discovered that the problem only happens if the crossover setting is set at the 12 o’clock position or higher!  It was in this position only for the burn-in process.  My normal crossover point is much lower than this position.

I still want to fix the issue but this is good news as now I don’t need to worry that the apocalypse won’t be triggered at any time during normal use!

 

I should also mention that after fiddling with position and the crossover and volume settings, my system sounds fantastic.  It took quite a bit of work to get to this point and I wasn’t sure I was going to get to a point where I get all the benefits people speak about when adding pairs of subs for music.  I had a small coffee table to the left of the left sub which was causing things not to gel.  When moving that coffee table away, everything clicked. What is amazing is that the benefits I notice the most don’t have anything to do with bass. The #1 biggest improvement is how solidly formed and coherent vocals become in the middle of the soundstage. 

As everyone says I found that using a pair is far better than one, as the benefits to soundstage and vocals are nowhere near as pronounced when using only one.  

Also, the one single thing I’ve not been happy with about my B&W 802 speakers is fixed - the image not follows you as you move left and right from the sweet spot.  Before the Rel’s, things fell apart even moving 2” off of the sweet spot.  What a relief. It was worth it just for that!

Sounds like you were experiencing acoustical feedback. Having the issue diminish or disappear all together when you moved the sub is an indicator that you were able to disrupt the phase relationship between the subs output and input and since you lowered low pass filter setting the offending signal is more than likely above that setting and no longer being reproduced by the sub.