KRK Rokit 8 phantom power?

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whitebalance

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Hi folks,

A pretty much complete noob here in need of advice.

I recenty got a pair of KRK Rokit 8s. Right now they're hooked up directly to my iMac using a Y cable (RSA to 2xTRS) and I've been hearing a slight but annoying hiss. I did some search, learned about ground loops and DI-boxes and figured I could connect it all using my NI Audio Kontrol 1 to a DI-box to the KRKs. So I went out and bought a Behringer Ultra-DI DI20 figuring it'd be enough to put between my AK1 and the monitors. I then proceeded to connect the AK1's outputs to the DI's inputs using TRS cables and the DI's outputs to the monitors inputs using XLR cables. Seemed like a solid plan, but when I hooked it all up I had no sound. Now, the DI20 is a really cheap box and is supposed to operate on either phantom power or a 9v battery. Suspecting my knowledge of how phantom power actually works is to blame, I pulled a battery from my bass, put it into the DI20 and voila, I had sound.

Two questions: are KRK monitors not supplying power over XLR or am I doing it wrong?
If I have to stick with the battery, anyone has any experience as to how long can I reasonably expect it to last?

Any extra tips/advice much appreciated :)

Thanks!
 
No, the KRKs do not have phantom power. The DI box is expecting phantom power on its output line from the interface or other preamp it is sending its signal to.
Forget the DI box, you should have the KRKs hooked up to the balanced outputs of the Kontrol interface.
 
Hey mjbphotos,

OK, so no luck there. I've tried to hook up the AK1 directly but the hum/hiss is the same (or worse) so I guess the only option for me now is sticking with the battery?

Thanks,
Wb
 
OK, before it was a 'hiss', not it's a 'hum/hiss'. Is it both? Hum is typically from an electrical issue. Is your iMac a laptop with a power supply? If so, try running it on battery, this my get rid of a hum.

Hiss - like the wind blowing, white noise. More often than not caused by a lousy component turned up too loud.

What are you listening to? Do you have a mic plugged into the AK1?
 
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As he said, forget the DI box. That's not what it's for.

Also, when you use that Y cable straight from the imac, it's an unbalanced output. It is likely to be noisy.


You should be hooking the main outputs (or any line outputs) from your interface to you monitors directly.

That can be via jack cables or XLR cables, but either way they must be balanced.
Are your cables definitely balanced?
 
Thanks for the replies, folks.

mjbphotos: sorry for being a little obscure on the hum/hiss thing, I just don't know how to describe it better (and english isn't my native language) but if I had to choose I'd say probably hiss is more precise. The iMac is a desktop but you just gave me an idea, maybe I'll try it on my laptop to see if there's any difference. There's no mics involved (actually nothing plugged into the AK1 audio inputs most of the time, just the USB connection to the computer). And I'm listening to everything from mp3 to my Logic arrangements, that makes no difference, in fact the hiss is audible better when there's nothing playing.

Steenamaroo: thanks for the tip. I'm not 100% certain the cables are balanced but I have plenty lying around, is there a quick and definitive way to tell a cable is balanced? About that DI box thing, I was hoping my problem is a groundloop and it would eliminate that. Actually when running off a battery it did eliminate most but not all of the noise, although being a Behringer I wouldn't be surprised if it introduced it in the first place :)
 
XLR to XLR cables will be balanced, almost certainly. If you're using a 1/4 inch plug to XLR or 1/4 inch plug to 1/4 inch plug then look for TRS plugs - Tip Ring Sleeve - not TS plugs - Tip Sleeve... TRS has two bands on the plug, TS has one. Google some pics and you'll see the difference....
 
Armistice said:
XLR to XLR cables will be balanced, almost certainly. If you're using a 1/4 inch plug to XLR or 1/4 inch plug to 1/4 inch plug then look for TRS plugs - Tip Ring Sleeve - not TS plugs - Tip Sleeve... TRS has two bands on the plug, TS has one. Google some pics and you'll see the difference....
Click to expand...

No XLR outputs are available to me, unfortunately, but I'll check my 1/4 plug's bands when I'm back home. Thanks for the tip.
 
Your interface has TRS outputs and the Rokits have TRS inputs, so get some TRS cables! Is whatever you are listening to (MP3s, etc) being sent to the interface via USB?
If you hear more hiss when there is nothing playing, you've got some level control(s) cranked up full - check your settings as well as all yoru input and output volume controls.
 
I think they covered it all.
I get why you used the DI box. You are right, then can be used for that purpose, but they are also designed to convert between different types of signals.
I think typically they take instrument level inputs (lower voltage than line level), and output mic level, or line level.

Even if it reduces the hum, it'll probably do more bad to your signal.

As said, look for Tip ring and sleeve.
What you don't want is a guitar cable, IE. tip and sleeve.

trs-ts.webp
 
Guys,

Thanks for the excellent troubleshooting tips and yes, now I'm 100% certain most of my TRS plugs are actually TS :) I did find one "true TRS" cable here though and tried it and plugged and unplugged and replugged stuff around many times but.. (and here's the big but coming) I didn't hear any change because when it finally dawned on me (and mind you, it was a serious DOH moment) and I unplugged everything except power, and left the monitors sitting on their own I was still hearing the same slight hiss coming out of them. Which leads me to believe that it's either a) normal and expected on active monitors (I've read something to that effect on some forum somewhere); or b) it has something to do with electricity (bad wiring? grounding? whatever). I'm finding a) hard to believe as these are supposed to be good enough for mixing and how am I supposed to EQ stuff when there's this unwanted extra being introduced in the sound. I'm kind of lost as to what to do about b), apart from having an electrician have a look at the wiring and stuff in my apartment.

I'm feeling unbelievably stupid for not thinking of checking the most basic thing first and I really do apologize for wasting your time (wasn't completely wasted though, I did learn new stuff!) and if you do have further ideas as to my further course of action (like, what to ask the electrician to look at first), it'd be much appreciated :)

Cheers!
 
OK, there is hiss coming from both speakers, with nothing plugged into them? Does it get louder when you turn the volume controls up? If the answer to both questions is 'yes', take them back to where you bought them.
 
mjbphotos said:
OK, there is hiss coming from both speakers, with nothing plugged into them? Does it get louder when you turn the volume controls up? If the answer to both questions is 'yes', take them back to where you bought them.
Click to expand...

Yes, it's both speakers and no, it doesn't get louder.
 
As you were unsure how to describe the noise before, try plugging the speakers into different power outlets throughout your residence - some circuits may be grounded, some may be wired backwards (+ to -) and see if this makes a difference. As you said the hiss doesn't change when you turn the volume up, I'm thinking this is an electrical interference/hum. Also try moving the power cable and the speaker around to see if this affects the noise.
 
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mjbphotos said:
As you were unsure how to describe the noise before, try plugging the speakers into different power outlets throughout your residence - some circuits may be grounded, some may be wired backwards (+ to -) and see if this makes a difference. As you said the hiss doesnpt change when you turn the volume up, I'm thinking this is an electrical interference/hum. Also try moving the power cable and the speaker around to see if this affects the noise.
Click to expand...

Ok just did that, man these things are heavy! :) Anyway, it's the same no matter which outlet I plug it into. Also, while I was listening to the monitor, I noticed the hiss is coming from the tweeter. I've googled some more, this time without even mentioning KRKs and it pretty much looks like a universal issue? There's tons of threads like this gearslutz.com/board/so-much-gear-so-little-time/672502-why-didnt-anyone-warn-me-about-hisssss.html (the forum won't let me post proper URLs until I have 10 posts) out there, so I'm starting to think maybe I'm just nitpicking.. :confused:
 
A universal issue? Nope. Not with good speakers. NO signal to them, there should be virtually no sound coming out of them. Think of your home stereo system - if you set it to CD player and don't have a CD playing, do you hear anything out of your stereo speakers?
 
mjbphotos said:
A universal issue? Nope. Not with good speakers. NO signal to them, there should be virtually no sound coming out of them.
Click to expand...

I duno, MJB. Fair enough, there shouldn't be a noticeable hiss,
but my mackies do hiss ever so slightly whether something's plugged in or not.

You wouldn't notice unless you put your ear up to them, but it's there.
It gets louder the higher up you turn the monitor level.

I have cheapo samson monitors too, and they actually have quite a distracting hiss.

Anyone here got these rokits for reference?
 
The OP said the hiss does not get louder when he turns up the volume.

I guess I'll stick with my cheap M Audio monitors,then, no hiss from them. I've also got a set of Altec Lansing computer speakers that don't hiss.
 
Which volume though? Interface, computer, or the actual monitor gain?

This has got me intrigued now.....


Is there really no noise at all from your maudios? Even up close?
 
Just tested mine. Yep, my KRK G28's also make a slight hiss with nothing plugged in. Nothing audible from over a foot away though. My listening position is over 3' from each, so I never noticed before. My Event TR8's make about the same amount of noise. Until now, I was not even aware this was happening, and it actually still does not bother me. How close are you sitting to your monitors?

I'll also add, that my fairly quiet PC makes more noise than the monitors do, and I cant hear that from 2' away. I don't even hear that from a condenser mic 8' away in the same room.
 
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