Problem with Behringer K450FX

Posted: 6/30/2014 12:33:07 PM

From: Finland

Joined: 6/30/2014

I finally bought a keyboard amp for my theremin: Behringer K450FX. I plugged my Etherwave in and...well got dissapointed. The sound was not the clean and pure theremin sound that I was looking for but somewhat distorted and fuzzy. Since I understand nothing about electronics I have no clue in finding out the actual problem.

My previous amp is a mini-sized active monitor by Boss and it sounds WAY better. It would be hard to believe that the new amp cannot take what the theremin has to offer. But what then..? Is it just that I cannot wait for a quality sound in this price range?

Any help..?

Posted: 6/30/2014 1:24:57 PM

From: Eastleigh, Hampshire, U.K. ................................... Fred Mundell. ................................... Electronics Engineer. (Primarily Analogue) .. CV Synths 1974-1980 .. Theremin developer 2007 to present .. soon to be Developing / Trading as . ...................................

Joined: 12/7/2007

"The sound was not the clean and pure theremin sound that I was looking for but somewhat distorted and fuzzy. Since I understand nothing about electronics I have no clue in finding out the actual problem." - Hande

The K450FX should be able to give a good clear undistorted audio out from your theremin. I have used quite a few Behringer products, and always found them to be exceptionally good - as good as most products at double the price..

"somewhat distorted and fuzzy." could be due to over-driving the input - You have a level control for each input, and a master level control - Plug your theremin into an input that is Line only (not one of the shared line/mike inputs) - turn the input level down to minimum, and slowly increase it, using the master level to adjust the loudness.. If the sound is clear until the input level is cranked up beyond some point, you have found the problem - keep the input level control below this level. I believe there is a way on most of these amps, to route a line input direct to the output bypassing effects.

The K450FX also has quite an extensive effects unit, with various routing possibilities - It may be that you have routed the signal through this and this is giving the 'distortion'.. Also, there is a graphic EQ with (I think) a feedback processor or at least an indicator.

This isn't just a simple amplifier (although, in terms of modern audio equipment, it is really simple ;-) - you cannot expect to operate it correctly without first reading the manual thoroughly, particularly if you aren't used to audio equipment, "understand nothing about electronics" and "have no clue in finding out the actual problem".

It MAY be that the unit is faulty - but I think it more likely that you are doing something wrong. I played a theremin (not an EW) through a Behringer amp last weekend, and it sounded fine - The band I was mixing had Behringer amps for the whole backline, and I was using a Behringer mixer for the PA driving EV amps and speakers.. No, I dont work for or get commission from Behringer, but have never seen one of there products misbehave or cause any problems.. But I haven't ever played with the K450FX- Have played briefly with some of their bigger siblings though.


Posted: 6/30/2014 1:31:39 PM

From: Colmar, France

Joined: 12/31/2007

Hmmm, I use a Behringer K450-Fx together with Etherwave theremins for years and can not confirm your observations. With all effects disabled and all eq pots in middle position it simply sounds "true". The Etherwave theremin sounds nasal and sometimes harsh, especially if one was used to play it through a guitar amp with bent frequency response before. Use the eq sliders to make the frequency response somewhat more round by attenuating slightly higher frequencies and consider upgrading your Etherwave with an ESPE01 module which has been developed in conjunction with this Behringer amp.

Posted: 6/30/2014 4:31:31 PM

From: Finland

Joined: 6/30/2014

Thanks for your replies. Having tried the amp once more the sound is actually clear but has a buzz within (becomes louder when played lower frequencies). The amp worked fine with my old Korg keyboard and the Etherwave worked fine with the old pair of active speakers. So it seems quite certain that I am the one not working...

Posted: 7/3/2014 5:01:09 PM

From: Finland

Joined: 6/30/2014

I ended up sending the amp back. There was something wrong with it; music played from a mp3-player got really scarmbled, sounding like a phone call with a really bad line...

Posted: 7/3/2014 6:50:09 PM

From: The Netherlands

Joined: 7/5/2012

I use also the K450FX for my Theremin, with no problems like this.
My brother had a (different) Behringer amp for his guitar and was defect after the first few ours of playing. It sounds like the speaker was blown up. This was a production fault. It sounds like a similar problem.

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