REL T5i Subwoofer Hum issue

One assumes you are using the speaker level inputs because your amp does not have a RCA sub out?

I suffered a ground hum using same method from my old Ayre ax7e integrated , never solved it.

Not sure if I paid any attention to whether it was specifically the pos or neg wiring that was the cause.

Some amps and subs will need a different connection for the negative.
Some will be fine off the negative speaker terminal, some will need the sub negative connecting to chassis ground instead.

Depending on your amp you may need contact manufacturer to see what they recommend.

I cheated and used a wireless Martin Logan sub.

Be certain the amp and subwoofer are powered from the same outlet. 

millercarbon

You might also want to read up on the reality that all low bass is mono. Theoretically there might be some recording somewhere that is not. In practice no one has ever produced such a thing.

Nonsense - even though it’s a claim commonly repeated - and I have recordings to demonstrate it. They’re consistent with the science of stereo LF - so you might want to check the references I previously provided to you. But again, if your system is wired for monophonic bass, then of course it will never produce stereo bass.

On the subject of stereo LF, you might want to review this thread that quotes Richard Vandersteen:

Modern sources such as streaming, CDs, DVDs, digital high-resolution music files, and Blu-ray Discs maintain full stereo separation to below 20Hz. Summing the channels into a single subwoofer reduces or cancels all the low-frequency information containing phase differences between the channels. Stereo subwoofers reproduce all of the bass information complete with the phase differences that help provide the imaging and location cues we use to place people and things at distinct points in the sound field.

Yes, a lot of stereo LF involves phase differences, as I’ve already explained to you.

I still don’t know why you’d suggest reversing system inputs (or outputs) to determine if a recording is stereo. There are easier ways, such as using your preamp’s mono switch. Of course, not everyone uses a preamp and not all preamps have mono switches, so while you may not have many alternatives, many do.

This is such an elementary first step standard trouble-shooting thing to do I just assumed everyone here would know about that. So okay, thanks for reminding me, lower the bar.

I understand that insulting others makes you feel "better," but you should know that an ad hominem attack is a basic form of logical fallacy. Your illogic simply reveals your fuzzy, disordered thinking. It joins your claim that "no one has ever produced such a thing" which is also a logical fallacy, because it’s logically impossible to prove a negative. Not that it matters much in this instance, because your premise is demonstrably wrong.

A Rel Arro should fix the ground loop issue that you are having.  My buddy had the same issue with the T9i.  Pm me if you want to buy an arro...

Not quite sure how all the bickering is helping to resolve the ops ground ( assumed ) hum issue?

Would be nice to know the amp the op is using to drive the Rel.