Anyone used a Behringer Combinator MDX 8000

Hi all,

Just picked up a Behringer Combinator MDX 8000, and wondered if anyone has any experience or tips with this bit of kit?

I’m using it in the processing chain of my internet radio project, and it was previously used in that roll on a few radio stations I’ve been involved in since 2003.

A real classic. Used by FM stations as a cheap but powerful Optimod replacement back in the 90s.

We have one in our STL playout chain, mainly acting as limiter with very moderate compression level.
For internet radio use just make sure the preemphasis (buttons at the back side of the unit) are switched off.


What does the preemphasis on this do? I’ve had no luck hunting down a manual, and Behringer support has been no help sadly.

In a nutshell, in FM broadcasting certain frequencies are boosted before transmission (inside the FM transmitter, before multiplexing), and reduced again in the receiver.

The limiter shall keep the output signal within the legal limits for the multiplex signal, so it must be told that this frequency boosting will happen further down the chain, and account for its effect on the MPX power.

When you use the unit for web radio etc., just turn preemphasis off. You only need it for FM.

Ah righty. I guess the reason its currently on is because it was used in the TX chain until recently. Its been since replaced by a £5k processor, that is all digitally setup.

Personally though I think the new processor doesn’t have enough flashy lights, but that’s just me :slight_smile:

Did you track down a manual/circuit diagram for the limiter, Matt?

Sadly no, haven’t had any luck yet