Audio hum

i need help correcting an audio hum i get when i connect my mac mini with a hdmi cable to my onyko receiver. i do not get this hum with any other audio source for my receiver. both the receiver and the mac mini are plugged into separate grounded surge protectors. i have changed the hdmi cable to no avail.

Tube amps are very sensitive, and video signals are noisy, there is very little you will be able to do about this, I can hear a hum through my speakers and I have solid state.
I doubt its an earth issue in this instance.

Similar Messages

Audio hum in recording on my Mini?

I just recently got the $799 Mac Mini version and when I record audio in Garage Band 3 or other audio apps I get a steady hum on the recording. I am using a powered MXL 990 mic through a mixer and then into the audio in on the Mini. The vocal recording sounds ok, except for this steady hum. I have plugged the Mini into a completely different circuit and it still happens. I have tweaked settings on the mixer, doesn't seem to matter. Any thoughts folks?

I've gone to the manufacturer's site, and the closest thing I can come up with to your part number is:
UB1002
http://www.behringer.com/UB1002/index.cfm?lang=ENG
They have online manuals and FAQ listings.
From their FAQ, I found this statement which mirrors most of what has been said, but also mentions where they suggest connecting from in relation to connecting it to a computer.
Read it over, and see if anything useful jumps out:
We recommend using the main outputs of the mixer to send signal to the inputs of the computer or soundcard. You will need to investigate which type of audio connector your soundcard uses, and you will probably need to obtain some adapter cables. You should be using the "line" level inputs on the soundcard. Be careful not to use the soundcard's microphone input, you might get some signal but it will not sound very good !
Depending on the configuration of your mixer, you can use a stereo channel input, a "stereo aux return", or the "tape in" connectors to feed the output of the soundcard back into the desk. As before, you will need to use the correct type of adapter cable. It is essential to check the routing of this input, otherwise you risk creating a feedback loop. You should refer to the instruction manual of the mixer for more details about routing the inputs.
To monitor your recording, your console is equipped with an extra output section, which is labelled "control room / phones". This output section has it's own level control, and it's own routing switches. Certain models are also equipped with a "pfl/solo" function - which opens up more flexible monitoring possibilities. This function is explained in more detail in the instruction manual.
With regard to the main supply of electricity - it is a very good idea to use a multiple connector socket to supply power to all audio devices, including the computer and screen, from one mains receptacle. The majority of domestic supplies will deliver the necessary current. This layout will reduce the likelihood of creating earth loops in the audio system. Computer monitor screens should be kept away from audio devices like active loudspeakers or electric guitars. If you still cannot eliminate mains hum - you should connect a DI box in the audio path between the mixer and the soundcard.
Please note the "Quick Guide" links below. Though they are model-specific, much of the theory will apply to many of our mixer products.
The rest of their FAQ's are at:
http://behringer-en.custhelp.com/cgi-bin/behringeren.cfg/php/enduser/std_alp.php?p_prodlvl1=117
Another thought I had, is that it is possible that your hum is being introduced with your adapter going to the computer.
So, you should make sure that that connection is made with high-quality gold contacts and shielded cables Pro-level cables.
One thing I would try, is to disconnect the mixer from the computer, and plug in head-phones to the mixer. See if there is a hum in the line with the head-phones (there should be a head-phone jack on most mixers).
Also, turn down (or off) any line that you are not actively using.
Hope this helps you out.

Inherent ground Loop/audio hum issue with Intel Core 2 duo?

Has this ever been resolved? I can't find a definitive solution:
We're a recording studio and have put a 2.16 Intel Core 2 Duo,
667Mhz running OSX 10.4.11 into service for a second workstation.
The audio I/O device is an Apogee Duet Firewire audio interface.
The Mac delivers a continuous 60 hz hum to the audio signal on the
output.
Tried a ground lift which did not resolve it at all.
Audio is clean on the headphone-out of the interface btw.
Based on searches, discovered this is a known/reported issue with
a number of Mac models - tho i've not found specific fix for this
particular model if any exists.
Apparently a Mac defect. Any suggestions?
We are a pro audio facility and things like cables and external devices
have been tested and ruled out. All definitely points to an internal
issue w/ the machine.
There are numerous old threads about CHUD developer tools(?)
But, NO version I've downloaded (i think we installed/deinstalled
'em all) has offered this "Nap" processor-adjustment option that is talked
about as having "fixed" this hum issue for MDD G4 and Intel G5 model users.
Love to hear from anyone who can help on this...Hate to have to dump a nice
Imac for this. (Everything's perfectly quiet about it except the audio out -
that kinda blows ; (

Hi, checking back in on this. OK, running a Macbook in place of the IMac with the same Apogee Duet firewire audio interface, the hum is not apparent on the output.
The iMac has a ground lift. All suggests that this is a known internal intel iMac problem and hope any fellow users could give me some idea of how to correct it before I must relegate this one from studio to office use. (we simply have to have clean hum-free audio monitoring...don't think that's asking too much eh?)
Again, there've been posts going back over the years about some form of developer tool adjustment that enables putting intel machine processors into a "Nap" mode.
Is there a version of the CHUD tools that will offer this option on this model?
(intel 2.16 core duo - 10.4.11)
Thanks for any other ideas
Mike

Getting rid of audio hums

Well - I have a Cannon GL2, and an external mic that I used to shoot. After I captured my footage, I noticed during some of my takes there's a low sounding hum underneath the entire take. Is there a trick to get rid of that? If not...uh oh!

I had the same problem with a huge amount of hum in a recording I made. I spent most of a day working with the built-in audio filters, including the hum filter. Nothing removed it. I read other posts where they recommended SoundSoap2 from Bias. I went to their site and watched this video http://www.bias-inc.com/downloads/videos/soundsoap2/movie.php a couple of times then ordered it through Amazon.com (which saved me about $40).
I got SoundSoap2 in the mail today and in about 10 minutes I had it installed and the hum removed from the video. It's easy to use (just watch the video and you are trained) and worked like a charm for me. I highly recommend this product.

Audio hum fix: I'm in SHOCK

For those interested in a rather strange audio problem regarding hum coming from the audio OUT: out of the blue today, my beloved Mac Pro started making what sounded like a ground loop coming through my speakers. I had made not physical changes to cables or anything and thought a cable went bad or I had a power outage or something. Turns out I bumped F14 on the keyboard and turned brightness down one (it is always at max) and once I hit F15 and put it back to max, voila...no more hum. I experimented and turned it down one, then two, etc. and the noise was even more prominent. WEIRD? YES. Happy my computer is still plugged in and not sitting at the Apple Store Genius Bar? YES, although I'm starting to think I should be behind that counter. Hope else finds help in my humor.

jfriend33 wrote:
Is there still time for OP to apply for a charge card and not get a 2nd HP? You should totally go apply for the PRG, go from an incognito browser window and when it shows 50k MR points after 1k spend in 3mos, click apply. If you get denied, its only a soft pull anyway! (i know it may not be easy with these expenses you werent expecting to have) And whatever the case, CONGRATS on the approval! The ED card kinda bugged me at first. I didn't think it was all that great compared to the others. That was until I found out the value of MR points! Easy to earn 1.2 and 2.4 which can really be worth even more if done right! Plus no annual fee. What will you plan on doing with your 10k points? If you get amex gift cards, its only 50 bucks. If you get restaurant ones, its $100. But if you redeemed for travel it could be worth a lot more! Pair that with the 50k from the PRG and you are golden!While an awesome idea - there's no way for me to meet 2 bonus spends. Largest expense is rent, and there's no way for it to be paid by anyway but check. Groceries over the next few months will take care of the 1k on the ED card. I'm not sure that I'd make good use of the charge card. Thanks for the info on the MR Points, its gonna take some time to fingure out what I want to do with them. And thanks for the congrats!

Audio hum in Photobooth videos on iMac

This just started happening on my Mom's computer, here's a demo video:
http://www.youtube.com/watch?v=OPCNV588m2Y
The audio was always totally clear in videos prior to today.
It's a 21" 3.06GHz running 10.6.4.

Remove any and all desktop speakers, connected speaker systems, headphones and the USB microphone.
Disconnect any and all other electrical devices from the same surge strip/wall plug that the iMac is plugged into.
Now reset the iMac's SMC > http://support.apple.com/kb/HT3964
+1. Shut down the computer.+
+2. Unplug the computer's power cord.+
+3. Press and hold the power button for 5 seconds.+
+4. Release the power button.+
+5. Attach the computers power cable.+
+6. Press the power button to turn on the computer.+
Then test the iMac using only the internal mic before reconnecting any other non- essential devices.
Now then if that clears up the feedback problem, reconnect and test your other devices one at a time.
If not, then there is an internal problem with the iMac and it needs to go in for service.

Audio hum removal

Anyone know how to get rid of a hum from a sound board recording of a wedding. The speaker sounds fine but there is a constant hum running through in the background. Tried hum remover but can't understand how that works.
Thanks in advance.
Brian

You're going to need Sound Soap, hopefully its 'learn noise' function can reduce the hum to an acceptable level. Nothing will totally eliminate it. The hum you got from the sound board randomly crosses a broad range of frequencies.

Editing audio from a FCP sequence

I have just finished editing a long sequence in FCP and now want to get rid of a background audio hum in the background of all the clips. What is the easiest way to export all my small audio clips into STP, remove the hum, then re-import into FCP.
I'm totally new to STP and finding the workflow very confusing.
Thanks!

RIght-click on the sequence in the assets window (default is Sequence 1, unless you changed the name) and click on send to>soundtrack Pro Multitrack Project

Video-dependent hum audible with CA-75U

Always had hum audible when N95 was connected to my TV/Stereo via CA-75U TV-out cable. Same problem in the car when connected to an Alpine 7-inch monitor. Now with N97, it's even louder. Definitely from Video signal, because, when the screen goes black when changing picture, the noise stops. Also, louder in "landscape" than in "portrait" mode. Who else has noticed the hum? Do you just tolerate it? Has anyone overcome it? I've emailed Nokia Care - so far they just suggest I try another TV (Nokia with head in sand again).
Seems to me Nokia goofed by putting audio and video on one 3,5 socket with shared ground. -Andy B.

"Solve" is relative. Using a good stereo hum filter on the red and white cinches works for me. Avoid, if possible, having audio and video cinches going to different devices (ground loops, especially when your N8 is being charged at the same time).
I "solved" the problem in my car, where video was going to a monitor and audio to the car radio, by blocking the ground connection of the cinch cable between N97 and monitor. Because the monitor and the charging device for the N97 had a common ground, the video worked, but only when the charger was plugged into the N97. No charger, no image.
(By now I have a different headunit, the N97 audio and video go into it, and I use an audio hum filter.)

How to eliminate a ground loop with SCXI units

I am using a SCXI chasis, the SCXI-1102 and 1303 and a 1602 USB interface. these are connected to grounded thermocouples fixed to an experimental apparatus. How do I eliminate the ground loop that forms when I power up my laptop (w/ 120V power) and to get accurate TC data? things work find when the laptop is running on batteries, but I don't have that much battery power!

Hi Gogden,
I have you tried hooking up the thermocouples differentially? This might eliminate the problem. Also, if you could give me some more information about the noise it might help me troubleshoot the problem better. Sometimes theres some noise due to lower quality power connectors on some laptops. This is typically associated with a 60Hz noise. Most of this is seen through a small audio hum when trying to amplify audio coming from laptops but it might be affecting the grounding of your USB DAQ card. You might try one of these audio hum eliminators around which may solve the problem. If you search google for "audio hum eliminator", you will find a variety of products for it. In conclusion, I would first recommend trying differentially and if that doesn't fix the problem you might look into the ground loop eliminator products out there.
Regards,
Paul Cason

Interlaced footage and resize question

Ok I am finishing a past project of creating DVDs from VHS.
Ok I have my clips captured they are DV-DVCPRO NTSC. I used audio filters to remove the audio hum from the VCR.
I want to remove the black border from the side and top of the video. Now my question is if i scale the video to fit wont that offset up the fields.
I am expecting to have 60i footage when I'm done.
Should I use Shake and separate the fields resize then re interlace them.

It's like a public access studio where they videotape live talk shows and that kind of thing. Below is a photo of it. Analog basically means they're shooting and recording the footage in the studio in NTSC analog where the pictures are interlaced one line at a time. They're also recording the output onto some kind of capture box (I have no idea what kind). Afterward, they're exporting the footage to whatever file you need. The exports they gave me were MOV but I noticed that my Premiere kept crashing every time I tried to edit and then export a finished edit. So I took the MOV files and converted them to MP4, which now works fine in my copy of Premiere. Below (the second to last link) is the converted MOV to MP4 file that dropped into Premiere for editying.
Download the BENS and SIMON exports below:
https://dl.dropboxusercontent.com/u/63110107/dmd-videos/SIMON%20Export.mp4
https://dl.dropboxusercontent.com/u/63110107/dmd-videos/BENS%20Export.mp4
Below is the converted MOV to MP4 footage I mentioned above:
https://dl.dropboxusercontent.com/u/63110107/dmd-videos/1NYEIntro_x264.mp4
And here is one of those graphics just in case:
https://dl.dropboxusercontent.com/u/63110107/dmd-videos/06.png

Power off after putting iMac to Sleep

Have you ever experienced this?
Put you iMac to Sleep and it powers down - not a shut down, but the power goes off - no blinking light, no whirring of the hard drive, no sign of life!
I have read and performed many of the tips regarding NVRAM, SMU, PMU, etc. resets. None have worked.
Situation 1-
Use the 'sleep' command - moments after the machine powers off.
Situation 2 -
iMac screen saver will run for a short time, then screen goes blank, the power light illuminates, the fan spins full speed, and the machine is totally unresponsive to mice clicks or movements, or keyboard entries.
Situation 3 -
Sometimes upon power up, the iMac doesn't start, but you can hear a faint buzz sound from the back of the machine. Similar to audio hum.
These problems occur whether or not other devices are connected to the iMac.
Connections-
Standard USB devices - mice, card reader,
Bluetooth keyboard
Ehternet
Power Settings-
Screen saver 5 minutes
Energy Saver - to sleep when inactive - 15 minutes, display to sleep - 15 minutes.
Various other settings tried with no change in problem.
I suspect the power supply. What's your opinion?
iMac g5 1.8Ghz, 1gig mem Mac OS X (10.4.9)

Any solution to this?
Put you iMac to Sleep and it powers down - not a shut
down, but the power goes off - no blinking light, no
whirring of the hard drive, no sign of life!
I have read and performed many of the tips regarding
NVRAM, SMU, PMU, etc. resets. None have worked.
Situation 1-
Use the 'sleep' command - moments after the machine
powers off.
I began experiencing the same thing this week (two days ago). I also tried repairing permissions, resetting SMU, and removing the iTunes receipts (Library/Receipts) since this is what caused an earlier failure to sleep. The difference is then the computer would not sleep, now it shuts off instead of sleeping.
Situation 2 -
iMac screen saver will run for a short time, then
screen goes blank, the power light illuminates, the
fan spins full speed, and the machine is totally
unresponsive to mice clicks or movements, or keyboard
entries.
Have not yet encountered Situation 2.
Situation 3 -
Sometimes upon power up, the iMac doesn't start, but
you can hear a faint buzz sound from the back of the
machine. Similar to audio hum.
I have experienced this (Sit 3) as well with my LaCie firewire drive connected, sometimes. I have found that powering off the LaCie resolves this, as does unplugging it.
These problems occur whether or not other devices are
connected to the iMac.
Connections-
Standard USB devices - mice, card reader,
Bluetooth keyboard
Ehternet
Power Settings-
Screen saver 5 minutes
Energy Saver - to sleep when inactive - 15 minutes,
display to sleep - 15 minutes.
Various other settings tried with no change in
problem.
I suspect the power supply. What's your
opinion?
iMac g5 1.8Ghz,
1gig mem Mac OS X (10.4.9)
Another difference, I am running OS X - 10.3.9, otherwise the same
Any ideas?
iMac G5 & Beige G3 Mac OS X (10.3.9) 1GB Memory, LaCie Firewire external drive

OS 10.4.10 Update Causing Audio Popping (AND HUM) Issues:

OS 10.4.10 Update Causing Audio Popping (AND HUM) Issues:
The problem on my Intel Mac mini with external Klipsch speakers (two mid-range/high and a subwoofer) is REAL obvious as the system emits a hum like a Spinal Tap amplifier turned up to #11 when 10.4.10 powers down the audio circuitry
Then, if I play a song in iTunes, it first pops and the hum disappears right before playing.
Quite annoying. I restored the mini from a recent backup to 10.4.9. Problem gone.
I'm glad I test updates on the mini before applying them to my Intel iMac 24. I guess I'll just hide & watch what happens before doing any more updates.
Here's what I sent to Apple tech support:
Guys/Gals (OS X Engineers):
Concerning the Snap, Crackle Pop Audio problem in the 10.4.10 update:
Please. Just do the right thing and fix the audio.
There is no need to power cycle the audio subsystem to save .0005 amps on the laptop line.
And then to make your Mac mini/iMac/other desktop users have to put up with it when using AC power is ridiculous.
Put the audio subsystem back like it was in 10.4.9 and let the laptop battery freaks looking for mini-amp savings get a "work-a-round".
Crikey!
iMac 2.16 Ghz Intel Core 2 Duo 2GB RAM Mac OS X (10.4.9) 20 Years of Microsoft-Induced Grey Hair
Mac Mini 1.83 Ghz Intel Core Duo 1GB RAM Mac OS X (10.4.9) 20 Years of Microsoft-Induced Grey Hair

Libby,
Backup is unable to make a restorable by Disk Utility backup. You can restore pieces of the software as outlined in my FAQ about backing up user data:
http://www.macmaps.com/backup.html
But to be able to restore a backup with Disk Utility, you need a cloning utility to have made the backup.
I suggest starting a new thread here, where someone else could help you out better:
http://discussions.apple.com/forum.jspa?forumID=752&start=0
First off, you'll get a wider audience who may be able to solve your problem. Secondly, responses to you won't confuse the original poster with solutions that don't apply to them. And thirdly, you'll know for certain whether or not a response applies to you.

I recently downloaded the latest OS update and now I have a constant "humming" noise from my MBP and my audio output is no longer working. Any suggestions?

I recently downloaded the lastest OS update (Lion X 10.7.4) on my MBP that I purchased in November of 2011, and since downloading it my MBP has been making a constant "humming" noise from the right speaker/disc drive area. I also don't have any audio output for FaceTime or Skype. I attempted to use Photo Booth to record a video and it doesn't record any audio. I attempted to reset SMC and reinstall Lion with no resolution of the problems.

Click the Finder icon on the Dock.
Applications > Utilities > Audio MIDI Setup
Built-in-Output
Output tab
Move the Master volume slider to the right a bit.
Best.

Satellite laptop: connecting video out to projector causes hum in (headset) audio output

Our church connects video output from the laptop to a projection system and audio out (via headset jack) to a sound board mono channel (line in). Stereo to mono adapter. We get a significant hum in the audio whenever the video cable is plugged in. Doesn't matter whether the attached projection equipment is on or off, it's all about plugging the video cable into the laptop. Unplug the video cable and the hum disappears. Obviously we have tried all sorts of things to isolate the problem but it all comes back to plugging in that video cable. We made sure there were no nearby power supplies or other equipment that might throw out interference. Has anyone ever encountered this problem and have any suggestions? Thanks in advance for any help you can offer.

Using a Satellite PSBY1U laptop. Video out is not HDMI but the other (VGA?) connector. We are connecting audio out from the headset jack direct to a mixer channel. No microphone is connected to the laptop. We looked at every sound and video-related menu we could find and could not see any settings that would seem to be relevant to the problem (we changed lots of settings anyway and nothing helped). Naturally we played with audio volumes, different auto cables, etc. Bottom line is we get clean audio until we plug the video cable into the laptop, then we get a very prominent hum from the audio output. Video cable goes straight to a projector, doesn't matter whether the projector is turned on or off. The audio and video cables are never closer than four inches from each other. It's weird.

Audio hum

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