Hi guys,

I am here to request your help about PA equipment.

I got two Active PA-Monitors "The box ma150" from thomann : http://www.thomann.de/gb/the_box_ma150.htm

Actually both are connected on output right and left on a very small mixer (XLR->Jack) like the one below, input on the mixer mixer goes into my PC as double-jack -> mini jack.



So, my question is : How do I add a SubWoofer to the system ? What do I need ? Once again those are active monitors.

Any thoughts ?

I don't know much about that interface and can't find what kind/how many outputs it has...

Also, what is a "jack" connection? Do you mean TRS?

And what sub specifically?

Pretending you have an audio interface similar to mine, I'll try to make it simple to understand since I have active monitors as well.

My outputs look like this..



I run TRS to XLR for each monitor, so one cable from each balanced output to each monitor. Then I would use a dual male RCA(red/white) to TRS/XLR(depending on the input of the sub) to run from unbalanced outputs 1 & 2 into the back of the sub.


This is probably a bit off from your setup, but hopefully the routing may at least give you an idea on how to go about it.

This post was edited by carmelhockey on Aug 20 2015 10:38am

Yes It is TRS.

What sub ? I don't know, I'm asking to know what is compatible with the setup. around 200-300€ I think.

About the mixer it is simple, it has only TRS inputs (2 per channel, 4 channels) and 2 TRS outputs.

Btw the "unbalanced outputs" on your pic send all the frequencys not only lowers ones right ?

Problem is the low freq should be cut from the monitors and sent to the sub, idk

Well, mostly anything can be compatible. The sub will have either XLR or TRS inputs. Idk if I ever seen RCA inputs on them.



I'm starting to understand more. Your active monitors are on the output of one of the four channels, correct? (One cable from each of the 2 outputs to each monitor)

If so, you'll be able to find a dual TRS(or even single, just run it from one of the 2 outputs) to single TRS/XLR cable and be able to run it from a second channel. The single TRS/XLR end obviously will depend on what sub you decide on and it's inputs.

As far as low ends from the monitors being cut, if you have EQ settings on your monitors then I would adjust the low end to your personal liking once you have the sub running. Having them all up may cause unnecessary muddiness, you're right on that.

And yes, my audio interface send the full stereo signal from each unbalanced output.

This post was edited by carmelhockey on Aug 20 2015 11:59am

If I'm confusing you, I'm sorry lol

If I understood well, you are telling me to act like the sub is plugged like the speakers and will do it's own work getting the right frequencies ?

I guess it's active sub only then.

Basically. Treat it as if it were a third monitor. But yeah, active would be best. Check out the 10" by KRK.

after some research I found out that I could (maybe) just buy a active sub with a build-in filter and go like this : Mixer -> Sub -> Speakers.

I'm reading that sending all the freq to the sub is not the best option for the sound.