In order to be more precise with this application, I will explain you the exact set up im aiming for.

I have an old dj mixer, the NUMARK DM1050, picking up dust for the past 1 year, and I recently decided to do some mixing on it, for practice. I have Scarlett Focusrite 2i4 (studio audio interface), a laptop, this NUMARK DM1050 mixer, and a pair of STUDIO active monitors - the JBL LSR 305. (if someone really needs pictures of ins and outs of the equipment, I can provide)

Here goes my thought for setup:

The laptop is running a dj softvare, 2i4 is connected to the laptop via USB cable, and a numark mixer is connected the 2i4 via RCA cables, where the channel one from the mixer with dual RCA goes to the 1/2 of the 2i4. Same for the second channel and 3/4 on the 2i4. Here is my problem:

I am not sure (since If I understood correctly, to get the output from this setup, I need to connect speakers to the mixer) If I can connect the RCA main out (L and R) from the mixer, to these JBL LSR 305 active studio monitors. The JBL's have balanced TRS input (which I use normally with balanced TRS out on the 2i4 when I do music production), but they don't have the unbalanced RCA. Is it possible to run RCA to TS cable from this mixer to these monitors? Will it do any damage? I really don't want to damage something up this is the only set up I have atm and the first time I do this kind of connection. Will it mess the ground? Are the cables that need to be run mono or stereo? What should I do?...

Sorry for the rather long post, I just want to get this right, and if it can't work, I want to be sure of that so that i know whether i should buy some up to date dj equipment. I would rather to that then damage my JBL LSR 305 studio monitors.

1 Answer 1


Yes, that will be fine. Generally speaking, the only way to cause damage would be to run a speaker output into a line or mic input. (Or to make the speakers do something impossibly loud - always a possibility with feedback if there's both a microphone and speaker in the system. So see my final paragraph below.)

A cable of this type can't be 'stereo'. It can be balanced or unbalanced. As an RCA output is inherently unbalanced, there's no point in using a TRS jack plug at the other end. The speaker will be perfectly happy with a TS jack plug.

The point of a balanced connection in this sort of setup is to reduce the possibility of noise and hum. I doubt you'll have a problem. But if you do, no damage will be done.

As always, when trying out a new setup start with the volume controls on the speakers right down. There's also a sensitivity switch on the speakers. Start at the +4dB setting, though you may well end up using -10dB.

  • Thank's for answering. I have to agree with your answer. Currently with 2i4 they sit at +4dbU. Will see about switching to -10dbV when i get the cables and connect to the dj mixer, probably tomorrow. I was considered by the thought that they are meant for studio monitoring and not for patching a dj mixer on it. Big PA systems play a role for that. But i hope, that as long as i'm not pushing them far through (usually im satisfied with no more than 75ish db) it should be okay right
    – Tomili
    Commented Aug 9, 2017 at 12:03
  • You can easily tell when speakers are being pushed too far, though some people seem to go into denial - "But I WANT it louder!" :-)
    – Laurence
    Commented Aug 9, 2017 at 13:20

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