...you say your setup is new?
 
If the HS50's are still under guarantee, and if it REALLY IS the speaker (not the audio cable, not the interface, not a faulty mains cable), then maybe just return it.

Wow! Thanks for all your responses!
I'll try all this out and get back to you.
 
So far have tried the 'input echo' idea, but no success there. I do have a Waves Guitar Interface connected, but disconnecting it/turning down the input volume didn't do the trick.
 
The setup is new - but not the speakers. They are the last remaining part of my previous system :)
 
I'll report back soon! Thanks again :)
 
Peace,
 
Darren

Like Mettelus, I'm most puzzled by the interference follows the speaker-part. That alone cripples most of the suggestions above. That combined with the fact that the interference occurs only when a SONAR project is open makes it really weird.
Actually, it's so weird that I'm tempted to believe there's some accidental inaccuracy in the problem description, as the issue seems almost impossible to me. How could the loudspeaker know if it's connected left or right...what kind of a malfunction in monitors/cables could cause noise only when a certain software is open.

Karyn
Sounds like you have an Input open with Input Echo turned on.  Try a new, clean project with no tracks and see if the noise is still there.  See if the noise appears when you add a new track with the 18i8 as input...
 
Have you left a guitar cable plugged into the 18i8 but not connected to anything else?

Thanks! Tried a brand new project with no tracks but interference still comes through. It is quieter without effects on. But still there.

Could be an issue in the speaker itself. That would explain why when I swap the speaker to the other side (and thus the other speaker lead and power cable) the noise goes with it. But could that be the case if it only occurs within SONAR (not standalone instruments)?
 
Also, speaker worked fine with previous setup. They have had a couple of months downtime while getting my new system going but should be fine. I guess it wouldn't hurt to test them with another system.
 
Cheers!

MacFurse
What a strange problem! First you need to eliminate a few things. Are the monitors plugged into the same power socket? If not, make sure they are. What type of leads are you using from your Focusrite to the monitors? balanced/unbalanced, jack to jack, jack to xlr ?  When you change the monitors around, are you simply switching over jacks on the Focusrite, or changing which lead is plugged into the monitor?
 
 
It sounds like a filtering issue, even if Sonar is somehow causing the effect. But if we can do a few tests and eliminate the leads or speaker, that will be a start. Does the interference stop if you hit E or click on the master FX button, turning off all effects?

The leads I have going from the Focusrite to the speakers are balanced TRS jacks to XLR. I've tried switching just the jacks at the Focusrite, but also physically moving the speakers to the opposite side and so swapping the power cable and speaker cable too. Yeah - strange as it sounds the noise follows the speaker, not the channel.
 
Muting the master FX button does make the noise quieter, but it is still there. Clicking the "Run/Stop the audio engine" button eliminates the sound completely, however.
 
Thanks for your help :)

mettelus
More thinking aloud here since this is a very odd issue. The "sound following the speaker" is what baffles me. Input echo should follow the channel, so a speaker swap would jump speakers. It is almost like that one speaker is more sensitive to EMI than the other, and both may be seeing the same thing, just only one reacts. Did I misinterpret the following speaker part?

The testing you did just makes things more complex; incredibly odd. You don't perchance have another set of speakers to test do you?

Yes, it does seem that one speaker is more sensitive to EMI, doesn't it?
I think that testing with another set of speakers would be of some help. I don't have any here but should be able to borrow a couple easy enough.
Cheers!

Kalle Rantaaho
Like Mettelus, I'm most puzzled by the interference follows the speaker-part. That alone cripples most of the suggestions above. That combined with the fact that the interference occurs only when a SONAR project is open makes it really weird.
Actually, it's so weird that I'm tempted to believe there's some accidental inaccuracy in the problem description, as the issue seems almost impossible to me. How could the loudspeaker know if it's connected left or right...what kind of a malfunction in monitors/cables could cause noise only when a certain software is open.

Truly bizarre isn't it. Yes, let's call the problem-speaker speaker B. When I have B on the left, the noise is on the left. When I have speaker B on the right, the noise is on the right.
The speaker alone can't be blamed as it only makes the noise when the 'audio engine' in SONAR is running.
SONAR/Focusrite unit alone can't be blamed as the noise can't be heard in headphones!
 
Whatever the issue, tough, it does seem that one speaker is more resistant to it that the other. Cheers!

jpetersen
Could be a ground loop problem.
You have one ground connection each through the HS50 cables and a third one through the interface, computer down to ground.
 
First, try using TRS jack-to-jack cables to the HS50's if you are not already doing so (looks like stereo headphone jacks) and ensure the cables themselves are balanced/"stereo".
 
If that doesn't help, try this:
 
Make (or get someone to make) a short extension cable about a foot long and use twin flex cable, not 3 core. The idea is to not have an earth connection.
 
Now put that cable between the buzzing HS50 and it's mains connection.
 
If that stops the buzzing, dispose of the modified extension cable (it can be dangeous) and get an isolating audio transformer to connect between your interface and the HS50's.
 
One good affordable unit is Behringer's HD400. It has two channels, so it will accomodate both speakers.

These ideas both seem worth trying too. I'm a bit out of my depth with the 'earthless extension cord' bit, but would be able to get someone to make me one. The HD400 seems to go pretty cheap anyway.
 
Don't have a balanced jack to jack on hand but should be able to get my hands on one easy enough.
 
Thanks!

dazzling

MacFurse
What a strange problem! First you need to eliminate a few things. Are the monitors plugged into the same power socket? If not, make sure they are. What type of leads are you using from your Focusrite to the monitors? balanced/unbalanced, jack to jack, jack to xlr ?  When you change the monitors around, are you simply switching over jacks on the Focusrite, or changing which lead is plugged into the monitor?
 
 
It sounds like a filtering issue, even if Sonar is somehow causing the effect. But if we can do a few tests and eliminate the leads or speaker, that will be a start. Does the interference stop if you hit E or click on the master FX button, turning off all effects?

The leads I have going from the Focusrite to the speakers are balanced TRS jacks to XLR. I've tried switching just the jacks at the Focusrite, but also physically moving the speakers to the opposite side and so swapping the power cable and speaker cable too. Yeah - strange as it sounds the noise follows the speaker, not the channel.
 
Muting the master FX button does make the noise quieter, but it is still there. Clicking the "Run/Stop the audio engine" button eliminates the sound completely, however.
 
Thanks for your help :)

This is what makes me think it is an open/noisy input...   What FX button are you referring to if you're using a project with no tracks?  FX bin on the Master bus?  Does it have Tape Emulator on the PC?  (Tape Emulator has a noise function...)