MP 1,1-5,1 Audio Lost On Left Headphone

[5comma1]

• Mac Pro 5,1 Mid 2010
• OS X 10.14.6 Mojave
• 2 x 3.33 GHz 6-Core Intel Xeon
• Memory 48GB • 6 x 8GB • 1333 MHz DDR3
• Boot Disk: 1TB NVMe M.2
• Firmware Version: 144.0.0.0.0
• Logic Pro 10.5.1
• Audio Interface: Focusrite Scarlett 18i8 (3rd generation)
• Sony MDR-7506 headphones (2)


- With the Focusrite audio interface connected to the Mac via USB, while using Sony MDR-7506 headphones (¼” TRS), sound has been lost on the left side.

- With the Sony MDR-7506 headphones plugged into the alternate headphone jack on the Focusrite audio interface, sound is still absent on the left side.

- Tried a second identical pair of Sony MDR-7506 headphones and performed the same steps as above. Sound is still absent on the left side.

- Completely removed the Focusrite audio interface from the Mac, and plugged the Sony MDR-7506 headphones directly into the 3.5mm jack on the front of the Mac. Sound is still absent on the left side.

- Plugged some wired earbuds directly into the 3.5mm jack (TRRS) on the front of the Mac. Sound is RESTORED to the left side.

- Mac OS System Preferences Audio settings: Headphones > Balance Centered


My only guess is that this points to an issue on the Mac side, but I’m not at all sure? Does anyone have any thoughts about where the issue lies and how to resolve it?

Thanks much in advance!

 

[mattspace]

- Plugged some wired earbuds directly into the 3.5mm jack (TRRS) on the front of the Mac. Sound is RESTORED to the left side.

My only guess is that this points to an issue on the Mac side, but I’m not at all sure? Does anyone have any thoughts about where the issue lies and how to resolve it?

Thanks much in advance!

Is the sound restored for the Sonys, or was that just for the earbuds?

• Sony plugged directly to the rear 3.5mm audio out?
• Earbuds plugged direct to the rear 3.5mm audio out?

 

[kitKAC]

Did you try the earbuds with the Audio interface?

 

[5comma1]

Is the sound restored for the Sonys, or was that just for the earbuds?

• Sony plugged directly to the rear 3.5mm audio out?
• Earbuds plugged direct to the rear 3.5mm audio out?

Thanks for your time and energy, mattspace.

Sound was restored when trying the earbuds... not the Sonys.

When plugging the earbuds and the Sony's into the back of the 5,1 I got no audio at all... just a faint hiss.

After writing my initial post I also tried plugging the Sony's into my Macbook Pro with the same result... no sound on the left side. This makes me think it's a Sony headphone issue, but I can't imagine how both pristine pairs of Sony headphones lost their left sides at the same time?

 

[mattspace]

Thanks for your time and energy, mattspace.

Sound was restored when trying the earbuds... not the Sonys.

So the problem is locked to the Sonys...

When plugging the earbuds and the Sony's into the back of the 5,1 I got no audio at all... just a faint hiss.

That's unusual - did you assign audio out to the rear line out port? The sound prefpane's menubar extra is good for that stuff.

After writing my initial post I also tried plugging the Sony's into my Macbook Pro with the same result... no sound on the left side. This makes me think it's a Sony headphone issue, but I can't imagine how both pristine pairs of Sony headphones lost their left sides at the same time?

Could be the audio interface blew out the left speakers?

It does seem odd - they're not smart devices with processing onboard or anything, are they - can they be switched off etc? (I recently added B&O Beoplay Portals hooked up over USB, but I've never had "good" headphones prior to that, so I'm not up on how they operate).

 

[5comma1]

Did you try the earbuds with the Audio interface?

Good question, kitKAC... thank you.

The Focusrite was disconnected earlier today and prepped to be exchanged due to a hardware fault. I reconnected the Focusrite now and tried the earbuds using a 3.5mm to ¼" adaptor and no sound was heard, left or right. This probably wasn't a reliable test, though, because the Focusrite headphone inputs aren't working properly. Confusion reigns!

 

[5comma1]

So the problem is locked to the Sonys...



That's unusual - did you assign audio out to the rear line out port? The sound prefpane's menubar extra is good for that stuff.



Could be the audio interface blew out the left speakers?

It does seem odd - they're not smart devices with processing onboard or anything, are they - can they be switched off etc? (I recently added B&O Beoplay Portals hooked up over USB, but I've never had "good" headphones prior to that, so I'm not up on how they operate).

Anything is possible, I suppose? I'm not up on how they operate, either? All I know is one pair of the Sony's is always with me at the computer, and the other is normally stored away as a spare... so I don't know how both left sides could have failed? And I don't understand why left and right of the earbuds work as they should when plugged into the front of the Mac... unless it's TRS vs TRRS related?

 

[mattspace]

Anything is possible, I suppose? I'm not up on how they operate, either? All I know is one pair of the Sony's is always with me at the computer, and the other is normally stored away as a spare... so I don't know how both left sides could have failed? And I don't understand why left and right of the earbuds work as they should when plugged into the front of the Mac... unless it's TRS vs TRRS related?

The front port is a speaker & mic port for headphones with an inlne mic, the rear port is speaker only.

Assuming that the left earcups of the Sonys are actually damaged (have you tried plugging them into an iPhone or similar. or some audio source that isn't connected to a mac?)

Did you test both pairs on the USB audio inteface, or was the second pair's first introduction to the setup being plugged into the line-out / headphone jack on the machine?

 

[5comma1]

The front port is a speaker & mic port for headphones with an inlne mic, the rear port is speaker only.

Assuming that the left earcups of the Sonys are actually damaged (have you tried plugging them into an iPhone or similar. or some audio source that isn't connected to a mac?)

Did you test both pairs on the USB audio inteface, or was the second pair's first introduction to the setup being plugged into the line-out / headphone jack on the machine?

have you tried plugging them into an iPhone or similar?
Yes, I plugged both Sony's into my iPhone using Apples tiny white 3.5mm to Lightning adaptor cable. There was no audio on the left side of either Sony headphone.

Did you test both pairs of Sony headphones on the USB audio interface?
Yes, and there was no audio on the left side of either Sony headphone.

 

[mattspace]

have you tried plugging them into an iPhone or similar?
Yes, I plugged both Sony's into my iPhone using Apples tiny white 3.5mm to Lightning adaptor cable. There was no audio on the left side of either Sony headphone.

Did you test both pairs of Sony headphones on the USB audio interface?
Yes, and there was no audio on the left side of either Sony headphone.

If you can't get left audio on either of the Sonys on any audio input, and the loss of left audio occurred after plugging them into the audio interface... It sounds like the audio interface has damaged them? Definitely one to take to Sony support, or if you bought them from an audio place, take them in and see if they can raise a sound on the left earcup.

 

[5comma1]

Great suggestions, mattspace.
Thanks for your assistance— much appreciated.

 

[Odessa]

Are the headphones brand new? Did you push them hard enough till the end? brand new headphones can have a bit more resistance sometimes. The left channel is at the end of the jack so it could be the headphones aren't pushed until the end. (see picture below) it could eventually explain the faint hiss when you connect the SONY with the plain earbuds: there is a short happening somewhere.

Otherwise I would try the working earbuds with the 1/4 jack adapter to see how it goes.

If all fail and the headphones are out of warranty, the last thing I would do is get a digital multimeter ($5) and try all points to see where is the short.

 

[mattspace]

The left channel is at the end of the jack so it could be the headphones aren't pushed until the end.

iPhones with the headphone jack used to have a problem with lint buildup in the 3.5mm port - amazing how much crud would come out with a small plastic toothpick. *lol*

 

[5comma1]

Are the headphones brand new? Did you push them hard enough till the end? brand new headphones can have a bit more resistance sometimes. The left channel is at the end of the jack so it could be the headphones aren't pushed until the end. (see picture below) it could eventually explain the faint hiss when you connect the SONY with the plain earbuds: there is a short happening somewhere.

Otherwise I would try the working earbuds with the 1/4 jack adapter to see how it goes.

If all fail and the headphones are out of warranty, the last thing I would do is get a digital multimeter ($5) and try all points to see where is the short.

Good ideas, Odessa... thank you.

I've had the headphones for many years. Bought them new... and use them infrequently and with care.

I pushed the headphone jacks in as far as they would go each time, for sure.

I will get a multimeter, as you suggest, and learn how to use it. That would be a good tool to have around.

 

[5comma1]

iPhones with the headphone jack used to have a problem with lint buildup in the 3.5mm port - amazing how much crud would come out with a small plastic toothpick. *lol*

So true... dust and crud are the enemy! I've been saved many times using the vacuum.