What needs to be determined- is that TRS jack on the keyboard, a MONO jack (left and right jacks), or a STEREO jack (like would go to a computer or a pair of headphones)?
Those require DIFFERENT cables and adapters to work in a situation like this.
If you plug a TRS-to-XLR cable into a STEREO TRS (headphone) jack, it WILL NOT WORK. Essentially, you are sending the left channel to the "positive" pin of the XLR (usually pin 2), and the right channel to the "negative" pin (usually pin 3). Essentially, the signals are, with the exception of the small amount of stereo, differential information between left and right, CANCELLING OUT, due to one being input into a positive polarity input, and the other into a negative polarity input, on the same channel!
The solution, is to first break out the signal into mono outputs (TRS stereo to TS left and right mono, or RCA left and right, or such), THEN plug those into the separate left and right inputs of an amp or preamp or into separate powered speakers.
Something like this:
Only at Sweetwater! ✅ Bulk Pricing for your Hosa CMP-153 Stereo Breakout Cable 3.5mm TRS Male to Left and Right 1/4-inch TS Male 3 foot!
www.sweetwater.com
... or this:
... is what's needed to properly break out left and right channels from a stereo TRS. Then, convert to whatever input jack type needed.
I have lost count of how many cases I have seen this happen. We probably get at least one call every few months about this, at work... people confused why their keyboard, computer, phone or other 3.5mm TRS device won't work with their powered speaker, mixer, recorder or whatnot. Breaking out separate left and right channels is a must.
The other alternative, if stereo isn't desired (say, you're going into a single input on a mixer, like is commonly done on keyboards on stage), is something like this. I use these a LOT, due to their problem-solving prowess:
That directly converts the stereo TRS signal to mono, allows ground lift, and converts it with a transformer, to balanced output. And the output level is adjustable, to avoid overloading an input.
They're definitely not cheap, but they ALWAYS work with EVERY computer, phone, keyboard or whatever that has a stereo headphone jack.
EDIT: I think this, actually, is the simplest solution to the problem here. Direct from TRS 3.5mm, to two 1/4" TS left and right output jacks:
Stereo Breakout Cable, 3.5mm TRS Male to 1/4" TS Female Left/Right Connectors, 6" Long
www.sweetwater.com
Just plug regular 1/4" cables from that to the speakers, of whatever length needed.
Regards,
Gordon.
