MP 1,1-5,1 Static, bleeps and noises from audio outputs on cMP.

[Upgrader]

Hi,

Has anyone else experienced this on their 5,1? Noise comes from all audio outs. It can occur when I scroll a web page or execute a command or it just generally happens on its own. I've seen other threads where people change the sample rates in the Audio and Midi settings utility but whatever I try it doesn't fix it. I've also tried plugging the Mac into different sockets and even different locations to no avail.

Any insight appreciated. Thanks.

 

[KeesMacPro]

With all audio outs you mean analog/digital and connected to an audio amp?
Does it occur connected to an audio interface (via USB/Firewire)?
Does it make the same noise on a headphone connected to the front audio output ?

 

[Upgrader]

With all audio outs you mean analog/digital and connected to an audio amp?
Does it occur connected to an audio interface (via USB/Firewire)?
Does it make the same noise on a headphone connected to the front audio output ?

Sorry, I should’ve been more specific.

Audio outs = front headphone jack and rear line output. I don’t use the digital out. The noise is heard through both these ports on headphones and a pair of active Yamaha monitors.

I haven't tried connecting a USB audio interface to test.

 

[HaypurTiryading]

Same situation is also valid for me. Front panel /w high empedance headphone is worst. Line out back panel /w active monitors better but I can hear in silent sections of music-video etc. I didn't tried digital out. Usb dac/amp didn't generates buzz-static. I think it's internal interference.

 

[jscipione]

No I haven’t so I wonder what’s different about your Mac Pro from mine. Internal interference from what? I’ve heard of coil whine issues from an aging power supply, maybe that could be the cause?

Do you have anything plugged into the audio input (mic) jack? (I know it’s a stretch.)

Could a noisy power line cause the problem? Plug into UPS to get a clean sine wave input. (Also a stretch)

Check for loose Bluetooth or WiFi antenna connectors inside below the processor tray.

 

[Upgrader]

No I haven’t so I wonder what’s different about your Mac Pro from mine. Internal interference from what? I’ve heard of coil whine issues from an aging power supply, maybe that could be the cause?

Do you have anything plugged into the audio input (mic) jack? (I know it’s a stretch.)

Could a noisy power line cause the problem? Plug into UPS to get a clean sine wave input. (Also a stretch)

Check for loose Bluetooth or WiFi antenna connectors inside below the processor tray.

Thanks.

Re mic input - no, nothing plugged in there. but when something is plugged in it makes no difference either way.

Re the ageing power supply coil issues - I’ve read other forums where people have this same noise issue but on much newer machines like recent iMacs.

I’ve asked on another thread whether a UPS might remove this issue if it’s power line related but I’ve not had a reply.

Re Bluetooth - I installed a Bluetooth antenna about a year ago to boost my signal so I could use a Magic Mouse and keyboard. The noise occurred long before this installation and continues to unchanged so I’d assume it isn’t that. Also my model doesn’t have a WiFi card.

It’s baffling and feels like one of those issues that if you took it into a repair shop you’d spend a fortune swapping parts out to no avail.

 

[KeesMacPro]

To answer the first question of the OP: I haven't noticed this issue, but I've never used the audio outs..
I've been working with different interfaces connected through USB or Firewire.

It can occur when I scroll a web page or execute a command or it just generally happens on its own.

So there are two sources of the noise I assume:
#1-Bluetooth signals/other high frequencies caused by the activity of the MP.
#2-noise through the power line caused by other sources connected to the same power network.

#1- a good quality shielded (audio)signal line should eliminate this issue. That is, if the noise is not "received" inside the MP itself. Another factor is lack of grounding: this not only causes (constant) hum, but also makes the best quality shielded cables completely ineffective: the cables function as antennas. So the Yamaha monitors (the good old classics I guess) should be connected to a proper grounded power lead as well as the MP.

#2- fridges, washing machines etc draw a lot of current especially when they startup , this causes High Frequency pulses that are transmitted through the power network. A good power leads filter is recommended or even inevitable if your working with audio.

Quote by HaypurTiryading:
I didn't tried digital out. Usb dac/amp didn't generates buzz-static. I think it's internal interference.

If thats the case, there's not much you can do except use the optical out or an audio interface...

An interface will definitely improve the sound quality, and doesn't have to be expensive...

 

[Upgrader]

To answer the first question of the OP: I haven't noticed this issue, but I've never used the audio outs..
I've been working with different interfaces connected through USB or Firewire.



So there are two sources of the noise I assume:
#1-Bluetooth signals/other high frequencies caused by the activity of the MP.
#2-noise through the power line caused by other sources connected to the same power network.

#1- a good quality shielded (audio)signal line should eliminate this issue. That is, if the noise is not "received" inside the MP itself. Another factor is lack of grounding: this not only causes (constant) hum, but also makes the best quality shielded cables completely ineffective: the cables function as antennas. So the Yamaha monitors (the good old classics I guess) should be connected to a proper grounded power lead as well as the MP.

#2- fridges, washing machines etc draw a lot of current especially when they startup , this causes High Frequency pulses that are transmitted through the power network. A good power leads filter is recommended or even inevitable if your working with audio.

Quote by HaypurTiryading:
I didn't tried digital out. Usb dac/amp didn't generates buzz-static. I think it's internal interference.

If thats the case, there's not much you can do except use the optical out or an audio interface...

An interface will definitely improve the sound quality, and doesn't have to be expensive...

Thanks for your thoughts.

I'm certain I can rule out bluetooth interference as the noise predates my use of Bluetooth. Re earthing issues - I don't get hum and all my devices are properly earthed. I'll take a look at power lead filters - I wasn't aware of these.

I'm also about to buy a USB audio interface and I intend using balanced cables to the Yamaha's (HS-50M's).

I'll report back and let you know.

 

[HaypurTiryading]

I'm using my Hifiman HM-801 as a dac-amp for my headphones and line out purpose. There is no buzzing sound. Works well from usb 2.0.

I am sure the buzzing-rattling-humming-crackling is based on internal interference and the workload directly affects the amount of interference. Other electrical components ( wifi-bt like rf devices, fans, hard-drives, gpu's, age of psu) and quality of wall power indirectly affects the sound line because it is not well insulated and grounded. I think.

I use real time voltage stabilizer and isolation transformer. Also, my cMP is kinda new. I bought 2 years ago, upgraded 3 months ago. It was not taken out of the box until upgraded. So my psu is not degraded. I do not have coil whine whistling but I'm experiencing same problems like you.

 

[Upgrader]

I'm happy to report back that I've just connected a USB interface and the static noise has disappeared completely! Relief! Plus the sound is noticeably better.

Thanks for everyone's assistance.