My monitors are picking up the radio

[DrGonzo]

It's quite weird actually. Both my active monitors are picking up a faint signal of some FM band, which is really annoying. Personally I never thought this could be possible - but maybe the reason is spelled Behringer. It's low cost - but I consider them to be well built. The sound does not come from the mixer or via the input cables - checked that. The only connector I've got is the power cable.

When I was at the electronics shop today I stumbled across these power extenders which "purifies" the power signal, and it crossed my mind that maybe this could be a solution.

I mean... could a FM radio band affect the electricity? And spread all the way to producing sounds from the speakers? I know it sounds far-fetched, but... I don't know. String theory is quite over my head as well...

/C

[spa]

Before I bought my monitors (not Behringer), I read a lot about various brands. I recall that one complaint of Behringer Truths was that they were prone to radio interference. However, I can't help you with a solution. You might try Behringer support, as they have probably heard this before.

[DrGonzo]

Seriously? Jaj... it won't be a huge investment to check if I can get rid of it with an extender that will remove EMI/RFI interference. But still... I am chocked that this actually could happen. Lesson 1-88: Always do your online check before you buy anything.

[bullshark]

Your monitors are most assuredly hooked up wrong, but since you don't mention how they're hooked up it's difficult to help you.

Are you going from unbalanced to balanced connection by any chance? If you are, lift the ground on the output side.

[kenn]

What model active monitors?

Radio reception in an amp circuit is a combination of RF being allowed into an amplifier's input, and some sort of nonlinearity in the amp at the RF frequency that demodulates it.

Some tests:

1) with NOTHING plugged into the active speaker's input connector, and power applied, do you get the FM stations?

2) with the input cable connected to the active speaker's input connector (eg the normal hookup), and power applied, do you get the FM stations?

3) Heat up your soldering iron. Find a 47 pf capacitor, and a connector that matches your monitor's input (probably phono or a phone plug). Solder the 47 pf cap across the connector terminals, then plug it into the active monitor. Do you still get the FM stations?

If you get the radio station in situation 1, the monitor's amp is WAAY too sensitive to RF. Or you live under the tower...

If you don't get radio in situation 1, but you do in situation 2, then something about the hookup jams RF into your monitors.

If you had radio reception in either of steps 1 or 2, but not in step 3, then you can probably make a small filter that can be added to the active monitor's input, or to its input cable.

Like so:



(pretend R is actually an inductor L1. I couldn't find a better image)

where
L1 = a few turns of fine wire around a ferrite core, like one from a cable TV balun transformer

C1 = 47 pf

This should kill any RF, but still pass all audio.

[pascual]

i returned a pair of berghr truths because of that! Shame on them.
Got me some krk 6 and i looove them.

[DrGonzo]

They are indeed Truths - B2031A to be exact.

When it comes up to my way of hooking them up - this is what I mean. Yesterday night I was searching the net about issues like this (should have done that before I pressed that damned Buy-Button!) and most people press on how important it is to use balanced cables.

Absolutely no unfriendliness meant to you, but I wouldn't dream of getting active monitors and then not using balanced cables. It's hard to see why ANYONE would do such a pointless thing.

So - yes, balanced XLR from the monitor, to balanced TRS to the mixer.

BUT! Here is the actual deal. IT DOESN'T MATTER if they are connected with audio or not. No matter what-so-ho-ho-ever. Yesterday I moved it from my working desk to a chair at a different location.

The only thing connected to it was - the power cord. And still it picks up the bloody FM band.

[bleebsen]

I'd say the chances of fm reception by AC power are quite small. The interference would have to be big fairly big on 220/110V and would have to survive the recification and filtering in the power supply.
For this to be the case your power mains would have to be HUGELY screwed - and you would have noticed before..

Does the noise disappear if you shorten the monitors input?

[DrGonzo]

Interesting point.
My monitors are set to the lowest input already - as the speakers are quite loud.
If I turn the monitor input up to max, I the noise rises but as far as I can hear - the FM band is not getting louder. I get the impression the FM interferance is at the same level.

A (maybe) interesting observation is that if I switch ON the MUTE HIGHS, the FM band gets louder. I can't really tell if I get reception in both the treble and the bass. I can only hear it from the treble - but if there is something going on with the bass as well - I really can't tell.

Should I get one of those nifty EMI/RFI interference eliminators, or simply face the fact that you get what you pay for?

[advaya]

The only thing connected to it was - the power cord. And still it picks up the bloody FM band.

I suffered the same problem with the same monitors. Nothing connected (other than power) either... It got so unbearable that after a few months, the behringers were demoted to TV speakers, and I picked up the Mackie 624s instead. Haven't looked back since.

[elwoodblues1969]

[quote="DrGonzo"]It's quite weird actually. Both my active monitors are picking up a faint signal of some FM band, which is really annoying. Personally I never thought this could be possible - but maybe the reason is spelled Behringer.

DrGonzo,

If I may seriously give you a friendly piece of critical advice,you had it right when you said;"but maybe the reason is spelled Behringer"

In the professional world of studio equipment,Behringer is commonly known as a consumer grade company that is trying to pass themselves off as professional and they are anything but that.
Even though Behringer products are found in pro music stores,it does not mean that they are pro quality.They simply exist to target the low income individual who is on a budget.

I once tried out a pair of Behringer desktops a couple of years ago and what a tragic waste of a $100!

Since then,I have read nothing but bad reviews on various websites on VARIOUS behringer products-not just monitors.

There is a reason why Sweetwater.com does not sell Behringer products.
Return or accept the loss of what you sunk into those monitors and do yourself a tremendous favor and avoid Behringer altogether at all costs.

There are plenty of other budget monitors out there that completely blow Behringer out of the water...trust me and do the research...you'll see what I mean very clearly.

Check out Samson,iKey Audio,or Alesis and I guarantee you will resolve your problem by simply going with another brand besides Behringer.

Elwood

[DrGonzo]

As the discussion are going - advaya, Elwood, Pasqual - I bloody knew this. But I was hoping that in the new enlighted 21st century would have brought technology at the point where pro-quality could be bought at silly prices. Hey... I actually still believe that. My Alesis active monitors back in Stockholm were cheap and I felt very comfortable with them.

Jaj... bloody hell. I've just lashed out silly money for Ohmicide, Sonalkis CreativeBundle, Guitar Rig 3, Cubase 4 upgrade and a bunch of AD plug. But I guess there is no real option here. Hearing the chewing-gum-trance-dance in the background when just switching on the monitors are a mighty killer of any creative juices that might try to manifest themselves.

Sigh.

[advaya]

Yeah, sometimes 'too good to be true' is exactly that... I did think the Behringers sounded OK. But yeah, the added musical background noise would really throw me off at times.

I've learned that there are some tools (monitors being one of them) where you really ought not skimp on... lest you enjoy the added work involved just getting yourself up to ground-zero.

BTW: wow mate... you're like, a member of the KVR elder-circle.

[c_huelsbeck]

My 2031As don't have this at all... their noise level is very quiet in fact. I read somewhere that a few batches of these monitors had manufacturing problems. Do you have still warranty? Might be worth to try a different pair before you throw in the towel.

[DrGonzo]

Yeah, sometimes 'too good to be true' is exactly that... I did think the Behringers sounded OK. But yeah, the added musical background noise would really throw me off at times.

I've learned that there are some tools (monitors being one of them) where you really ought not skimp on... lest you enjoy the added work involved just getting yourself up to ground-zero.

BTW: wow mate... you're like, a member of the KVR elder-circle.

I think you are completely right. In fact, it goes for most. You usually get what you pay for - but then again, I was perfectly happy with my old Alesis. And they are in the same price range (in fact a little bit cheaper).

KVR Elder... hahaha... indeed. Leviating Fire-Breathing Overlord with the ability to communicate with slugs More chocking is that KvR's been around for so long.

c_huelsbeck: Yes - I read about this. Many people have just good experiences from the Truths - many don't. I still got a valid warranty, but I'm quickly losing my faith. Mailed the Behringer support quite some time ago, and no reply. And it's a bit apalling that they don't even mention this issue in their knowledge base. I have read MANY reports about people having this problem.
If they don't want to talk about it it can mean three things: 1) they aren't aware of it, 2) it is an extremely rare condition not worth talking about, or 3) they don't want to mention it because it could affect sales.

I read a review on Harmony Central that was dated 2004, about exactly this matter. So for me it sounds odd if Behringer don't know anything about this.