Hi

I have connected my monitors to an Edirol FA-66 firewire audio interface using good quality shielded balanced TRS-XLR mic cables (or so I believe). The FA-66 has balanced outputs. The monitors have balanced inputs. My problem is, that each menu opening, each menu selection, each window activation and each operation that affects screen contents, is audible.


Questions
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1) Are there other Firewire audio interfaces with lower noise than the FA-66? (req: Dual balanced XLR inputs, dual balanced TRS outputs).

2) I assume that firewire bus power is a bad thing. Is this true? Can I do anything about that? Get a powerless cable? Or is this a grounding issue? My PC and my Edirol/monitors are connected to two separate wall outlets... There seems to be a screw at the rear of the interface...


Tests that I have done so far
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1) First I disconnected my CRT from my computer and from power. This did not acceft the sound. Hence, the sound is not caused by RFI from the display. I also typed with my wireless keyboard and used the mouse. These did not cause any audible noise as long as there was no change on screen. The noise must thus be correlated to either CPU use or GPU use. This interference is not trasmitted through air, as the noise disappears if I disconnect the monitors from my audio interface. So, something comes through the cabling.

2) I disconnected the FA-66 from my computer but not from electricity. No audio signal. No audio input cables. No firewire cable. This caused background noise. Hence I must deduct that Edirol FA-66 is not very quiet.

3) When I connect the Edirol to my computer using Firewire, the noise becomes louder. If I turn on firewire bus power on the FA-66, the noise becomes still louder. This is very very annoying. I fear that the bus power carries noise from the circuit board to the FA-66 and affects the amplifier or something...


Any hints would be very very welcome.

Is your Firewire integrated with the motherboard or do you have a separate PCI card?

If it is integrated, odds are that the power supply isn't clean and, as you suggest, you are getting interference from the GPU/CPU.

I hear similar things on my (cheap) integrated audio.

Is there an option to use a different power supply for the Edirol?

Also, go to the sound settings in the control panel and disable all system sounds.

Make sure all your devices are plugged into the same power strip on the same plug. (do not assume that all the power plugs in your room are on the same circuit.)

Firewire bus power is NOT your problem.

Try disabling the onboard sound in the Hardware Manager.

Since you hooked up the interface with no computer and still got noise, you should be calling in an electrician to make sure there is not a problem with your power.

The firewire is an itegrated one (Tyan K8WE motherboard). The firewire interface is connected to the same chip as one of the PCI-E slots. Maybe I need to try with a PCI-Firewire card (or move the GPU).

Edirol comes with an "optional" little black transformator of its own - and it helps a bit but there seems to be some noise even if I use external power.


Ok, I'll try the same power strip for the computer, FA-66 and monitors - and I'll make sure the onboard sound is disabled.

[edited: removed quote and simplified a little - sorry for doing in in the middle of conversation]

The firewire is an itegrated one (Tyan K8WE motherboard). The firewire interface is connected to the same chip as one of the PCI-E slots. Maybe I need to try with a PCI-Firewire card (or move the GPU).

Edirol comes with an "optional" little black transformator of its own - and it helps a bit but the bus power is still present (even if not used) and it still seems to affect sound even if I use external power.

To avoid having the bus power reach the Edirol at all, you could use adapt your 6-pin/6-pin Firewire cable to go through a 4-pin intermediate. i.e., get a 6-pin to 4-pin adapter and use a 4-pin to 6-pin cable.

My notebook has similar noise issues with the built in audio. I only notice it much with headphones, but it is so noisy as to be intolerable. Haven't checked it with any kind of external output.

I'll also try a shield isolator adapter: http://docs.info.apple.com/article.html?artnum=86655

Hi Ralf,

Looks like it's time for me to chip in a "first post" to DV Info!

1. Looking at the Edirol FA-66 site, there's mention of a couple of ferrite cores and how to attach them to the Firewire cable. Do you have those and are they attached? See http://www.roland.com/products/en/_support/om.cfm?ln=en&dsp=0&iCncd=688

2.1 This box appears to have zero-latency/direct monitoring. Do you hear the noise when only direct-monitoring inputs? (cranking that direct monitoring volume full clock-wise should do the trick)

2.2 Do you hear the noise when using only Out1/2? (cranking the direct monitoring volume full counter-clockwise)

3. Looking at the K8WE specs, the Firewire support is via a TI chipset so that's probably not the problem - interfaces based on them tend to be the most reliable of those available. See http://www.tyan.com/products/html/thunderk8we_spec.html

4. How close is your computer to the Edirol box, and is the computer's case of all-metal construction?

5. Looking through the Edirol's manual (RTFM ;-), looks like there are a bunch of conditions listed in the troubleshooting section that seem to cause noise issues, e.g. LAN activity. Could be that you need to rev some drivers and/or BIOS for the K8WE.

That's all that comes to mind... I use a Presonus Firebox; works for me. :-)

Andrew.

The noise is affected by speaker volume and on-screen activity and digital vs. analog input. Ferrite cores are in place. The Edirol is of all metal construction (and it has two RCA inputs sticking out...) and my computer is made of aluminum, but it has some plastic parts too (like an USB/firewire front panel). All the expansion bays have metal mesh in front, though.


Testing done so far:

POWER
1) the speakers, external soundcard and computer are all plugged to the same power strip
2) the Edirol uses its own external power adapter
3) the firewire cable connecting the Edirol to the computer has been changed to an 6-to-4 cable that does not carry bus power
4) turning off the Edirol or disconnecting the audio cables from outputs removes all unwanted noise

- So, either this interference comes directly from the power strip to the card/speakers (probably solvable by UPS?), or via firewire signal/grounding, or then it is radiated RFI to the card or speaker cables. Certainly not bus power related. My speakers are all metal (metal mesh in front of elements, too), so they should not directly suffer from through the air RFI.

CONNECTIONS
5) onboard sound has been disabled in BIOS and all system sounds are off
6) if I disconnect the the firewire and only let the power cord and the audio cables remain connected, a very loud constant buzz is heard (is that a ground loop?), but it goes away if I connect the (disabled) motherboard sound to RCA-IN. The buzz actually disappears the very moment the male RCA sleeve gets contact with the Edirols RCA-IN (not casing). Changing firewire to RCA does not affect the GPU-related interference. So, both the disabled onboard sound circuitry and the external sound card are affected.
7) I installed an firewire add-on card to a PCI slot. No effect.
8) motherboard has TI firewire chip, the PCI card has an VIA firewire chip
9) I moved my GPU to another PCI-E slot. No effect.

- the noise is hence not firewire related and it is not in the "signal" either as there should come no sound from the disabled onboard sound circuitry. The noises must then either come from power to spk/card or from the shielding of signal cables or caused by RFI (radiated) to the card itself (or cables, but when the Edirol is off, there's no interference - on/off could affect the cables susceptibility to noise though).

MISC
10) changing the direct monitor mix does not affect the noise. The noise can be heard when monitoring the input only (and there's no input signal...) or the outputs only.
11) Output 1/2 (main out, TRS balanced) and output 3/4 (TRS balanced) both have the noise
12) changing RCA-IN attenuation or output volume on output 1/2 does not affect the noise.
13) It's also important to note that AFTER the output volume adjustment the signal goes both to output 1/2 (speakers) and to phones. The phones have absolutely no unwanted noise. Powered speakers behave differently from headphones though, and they might also be less sensitive...

- If the noise would come with the signal, then certainly input attenuation and output volume would affect it. So, possible causes left: interference to the shielding of signal cables (rca, firewire) or RFI through the air to the soundcard itself or RFI to the audio cables, or bad power.
- Does the clean headphone output give a clue?
- If I select "Digital In" in the Edirol, I hear absolutely no unwanted noise (or sound). Could this be a lead?

The firewire cable is totally digital, no interference is possible, under extreme conditions it's possible to flip bits but you'd probably be dead from that much RF.
Try grounding the Edirol. Run a wire from the rear ground screw to one of the PCs case screws. Check that the PC case is earthed. As far as I know it's impossible to get an earth loop from the mains when you're running from a wall wart. Those wall wart power supplies do not carry the mains earth through to the secondary / DC side. In fact those units are supposed to withstand 500V between mains and output, I know because I have to test ours, monthly.

Probably nothing to do with it based on your symptoms but make certain you have disabled or better yet uninstalled original sound card drivers. This one really threw me when I installed M-Audio Firewire 410 onto a laptop.

... and there's no ground in the 4-pin firewire either: http://www.zytrax.com/tech/pc/serial.html so this cannot be a ground loop.

My computer is grounded and I also tried to ground the Edirol. No effect.

The fact that digital-in mutes all interference and that there is less interference with RCA connected and at zero volume, than no RCA at all, points to the RCA input. Maybe it gets some RFI even when no cable is connected. It is a 5-6mm long "antenna" after all...

Noise not affected by output volume control must travel in the shielding, right? So a ground lift...?