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stooby3535 Level 1 Level 1 (0 points)

I am encountering a faint but persistent high pitch noise through my Yamaha HS-50M monitors when my Edirol FA-66 interface is plugged into my computer via firewire ca ble.


I've read all these threads which sound very similar to my issue and have tried all the pertinent recommendations presented so far:


Monitor buzzing noise NEED HELP!


Help fixing signal hum/mouse coming out of monitors?


Electric shocks and Noise in a home studio


KVR :: View topic - Interference question. Computer and external audio interface


Just to be clear, my problem is similar but not identical to the problems listed in the threads above. Mouse movement or computer activity doesn't effect the monitor noise I'm hearing at all, it is merely a constant sustained high frequency tone that's emitted from my monitors when my FA-66 interface is plugged into my MacPro via firewire cable. My speakers are silent (aside from their own self noise) so long as my FA-66 isn't connected directly to my computer. Even when my FA-66 is powered on via its AC adaptor but not connected to my computer via firewire cable there is no added noise in my monitors. It's just when I make the firewire connection between my interface and my computer that the high pitch noise appears in my monitors.


I used to run my Edirol off of my older MacBook and never had this issue. I just recently upgraded to a new MacPro and am encountering this issue for the first time.


Since the noise is eliminated when I disconnect the firewire cable from my interface, I believe the sound is being caused by interference from my computer, which is then transmitted through my firewire cable into my interface.


My setup is this:


Grounded Wall Outlet > Furman Power Conditioner > MacPro Desktop Machine > Edirol FA-66 > Monitors


I am using TRS-XLR Mogami Speaker cables to connect my interface to my monitors and am using Mogami cables throughout my system.


All of my audio gear is being powered through my Furman power conditioner: my computer, my FA-66 interface via its AC adaptor (not firewire bus powered), my speaker monitors, and all my other audio equipment.


I don't believe I'm picking up interference from any of my other cables and wiring and this doesn't seem like a grounding issue. Like I mentioned, the noise is gone when I disconnect the firewire cable from my FA-66 interface.


I do have some other hardware in my setup (my computer screen monitor, a USB hub, AC power supplies and cords to power external hard drives, a lamp) that are receiving power from a separate surge protector strip plugged directly into a different wall outlet than the one my Furman conditioner is plugged into. I don't believe any of these other devices are the cause of the interference noise because when I unplug all these items from their respective wall outlet, I still hear the exact same noise when my FA-66 is plugged into my computer via firewire cable.


All signs seem to point to my firewire cable and/or my computer.


Originally I started with a different firewire cable and swapped it out for a newer and higher quality, gold-plated firewire cable meant to cut down on interference. This cable swap did help reduce some of the noise my monitors were picking up, but did not eliminate it entirely.


I then invested in some ferrite core clamps and placed those around each end of my firewire cable (one right by my computer's firewire port & one right by my FA-66's firewire port). This helped a little more but did not eliminate the high pitched sound entirely, just made it even quieter. The hole diameter of the ferrite core clamps is slightly larger than the diameter of my firewire cable, however, and I'm going to order more clamps with a smaller hole diameter that will ensure a snugger fit around my firewire cable. Do you think this may help things more?


I also lifted the grounding pin in my Edirol, tied a copper grounding wire around it and connected the other end to my MacPro's metal case with alligator clamps in an effort to better ground the two suspect pieces in the chain. This seemed to have little to no effect beyond what the ferrite cores were able to clean up. (I got this idea from the GS thread contained in the first link above.) I don't know much about hardware electronics but thought I would try this out just to see if it would help. The fact that it didn't help, to me, seems to reaffirm that the system is grounded properly, because if it weren't I would have possibly noticed an improvement by making a grounded connection between my interface and computer. Please correct me if I'm wrong about this.


I even tried plugging my Furman power conditioner into an entirely different wall outlet, but this didn't change things at all. I do have one more unused wall outlet I can try but don't think this will make much of a difference because I'm 99.99% sure this isn't a grounding problem and that the sockets I'm using are properly grounded. My Furman isn't registering anything abnormal and seems to be functioning properly.


As of right now I've been able to make significant improvement to the noise problem and have eliminated it by 90%. The high pitch noise through my monitors is virtually eliminated but I still notice a faint bit of added noise when interface is powered on and connected to my computer via firewire versus when the firewire cable is disconnected.


Could my MacPro be outputting some kind of interference which is being picked up by my firewire cable and transmitted to interface and monitors? I've read that sometimes a computer's power supply unit can output a large amount of EMI or dirty electrical interference. It seems surprising to me that Mac's professional desktop machine would cause a fundamental issue like this though, especially since it is designed for being able to work in a professional audio recording setup.


Any other ideas people can provide as to what may be causing my added interference and how to treat it would be greatly appreciated. Thanks in advance for your help!

Mac Pro, Mac OS X (10.6.7), 2.8 Ghz Intel Quad-Core, 16GB RAM
  • bennytlb Level 1 Level 1 (0 points)

    I have the same problem. I am using a macbook pro to do playbacks. i hv tried the ferrite core, no help. but as soon as i un-plug the mag safe power adapter, the noise disappears. The buzz is at very prominent at 9khz. It is very annoying when i do long shows. i have tried to move mains too, and that didn't help. My next try would be getting power through a UPS when it comes available.


    my set-up... USB soundcard.(behringer) not the greatest but did not have any problems with it on my other setup which is a DELL notebook.


    Any respond from APPLE? In may have to ditch this 4mth old macbook pro if i can't find a solution for it and go back to the old PC!!!

  • stooby3535 Level 1 Level 1 (0 points)

    What kind of sound card are you using exactly? It seems like you're sound card is picking up EMI or RFI from your computer when it's plugged into a wall outlet. Are you using a power conditioner in your setup to help clean up your power supply?


    Try googling EMI & RFI, there are many online resources which detail how to troubleshoot and deal with these problems.


    I finally solved my problem by upgrading to a higher quality audio interface (Focusrite Pro 40). This was able to cut out the high frequency RFI signal being output from my MacPro computer. I get the feeling many of Mac's higher end computers tend to output dirty electrical signals which is why so many people have this similar problem.


    Try cleaning up your power supply, then maybe use different, higher quality sound cards or interfaces with your setup to see if the issue gets solved. The problem most likely lies with your computer and if you can get a high quality interface that can cut out the noise, that may be your only solution. It worked for me.


    Good luck!

  • bennytlb Level 1 Level 1 (0 points)

    the noise is also apparent on the headphone output. So it is actually generating from the 'Book' itself. I have been using this sound card for some time on a PC, and it has never given me this problem. So i don't think it is the sound card problem. like u, I need a clean Output. U would think that a 'PRO' machine like this would be best for our applications out of the box. but actually not, when the basic stuff we need from it is a clean n clear audio output. Now I have doubts of running a recording software on it. i think i will still hv to rely on my HD24 for recordings.

    Getting a clean source of power is quiet difficult when most of my shows are outdoors n builted up overnight, and power coming from generators. My enviroment is mostly FOH and broadcast gigs, and i need a 'clean' sounding machine out of the box. Looks like the old PC may soon be coming out to travel again  if i can't find a fix for this problem.

  • stooby3535 Level 1 Level 1 (0 points)

    It definitely seems like your MacBook Pro's power supply is the source of the noise issue. You can either replace your computer's power supply unit or get a higher quality sound card that will be able to filter out the noise. I realize it's probably not your sound card's 'fault' but I had a nearly identical problem, and using a higher quality sound card eliminated the noise emanating from my computer.


    If you're doing shows outdoors with non-standard power supplies, then a power conditioner and regulator for your setup is even more necessary to ensure a clean and constant power to your gear. Try looking into Furman's line of conditioners and regulators as a starting point and you can also try checking out for more options.



  • Nidocamen Level 1 Level 1 (0 points)

    Stooby, I'm having the same issue you described.  But with a MacBook Pro.  The noise exists when it is on battery power, so I'm guessing it I just bad electrical noise in the computer components.  But anyways, I am considering the FocusRite Saffire 6 USB, since I don't need many inputs/outputs.  I am curious if the PRO 40 worked for you 'out of the box' and solved your problem?  Or did you have to tweak settings on the unit or with the mixing software it came with?  The Saffire 6 doesnt come with that software and I want to ensure that I can solve my noise issue like you did.  Any help would be appreciated!


    Thanks :)



  • meridiandevv Level 1 Level 1 (0 points)

    I have same problem as original poster on Mac Pro early 2009.

    This is a repeat of problem introduced in 2010 with an Audio update 10.6.2 with almost the same symptoms (see here: )   Incredibly frustrating that it was fixed a few months after it was introduced in 2010 only to make a reappearance now in Lion.


    The high pitch whistle, as in the 10.6.2 problem, disappears within seconds of unpluggin the firewire audio interface.   There is nothing I can do to tame it other than unplugging.   


    Come on Apple...   just fix it (again).

  • meridiandevv Level 1 Level 1 (0 points)

    An update to previous post - there was a fix from Apple for 10.6, here:


    I suspect that, since this fix was just for certain Mac models that it needs to be reintroduced now for Lion.


    Has anyone submitted a bug report for this?

  • meridiandevv Level 1 Level 1 (0 points)

    Submitted bug report (9959369)

  • meridiandevv Level 1 Level 1 (0 points)

    Has anyone successfully eradicated this problem with the 10.7.1 update out today?

  • Sirthoms Level 1 Level 1 (0 points)

    Is this fixed or not? It´s extremely annoying and I can´t use lion because of this.

  • Sirthoms Level 1 Level 1 (0 points)

    Everybody ded here or what? NO ONE knows about this ****????

  • Heraldo Jones Level 1 Level 1 (10 points)

    same problem here on mac pro 2009 4,1 with 10.7.2 and TC ELECTRONIC IMPACT TWIN   , I can't understand why this problem is back again ?????

  • Sirthoms Level 1 Level 1 (0 points)

    I now have a high pitch sound coming from the power supply (I guess) all the time, no matter if I´m using Snow Leopard, Lion or Mountain Lion. I have disconnected ALL cables but the powercord and still the high pitch sound is there.


    Anybody with the same problem?

  • Sirthoms Level 1 Level 1 (0 points)

    Ok I´ve discovered that the high pitch noices actually came from my optical mouse (logitech MX518). It had 3 static high pitches at 5, 10 and 15 Khz, very strange. They disapered after removing the USB cable.


    But in Lion and Mountain Lion the 8Khz pitch is still there when using my RME fireface 400. I have contacted apple support and they say they are on the way to fix this. They will contact me again when the fix is out. Until then I am stuck to Snow Leopard =(.

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