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shoeshine

macrumors member
Original poster
Feb 27, 2010
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0
I'm not able to figure out how to get the line 3.5mm audio jack on the new MacBook Pro to act as a line in port. This is a non-touch bar 13" MacBook Pro. I do remember reading that they dropped the optical out from this port, but was under the impression that it was still possible to use this port as a line in. I'm plugging in a stereo 3.5mm plug from a line out from a mixer. But when I pull up the sound input options in systems preferences, it only lets me select internal mic as the option.

Is this no longer possible on a MBP?
 

Chancha

macrumors 68020
Mar 19, 2014
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I think this is the case, the jack is now purely a headphone output / line level output. I don't own any of the 2016 so can't verify, but I remember specifically confirming this in an Apple Store. You can do this to be 100% sure: plug an input from your mixer, then check system profiler > Audio (Build In), it will list out all the available / possible audio I/O's and all the 2016 models have "Line Input" and "S/PDIF" missing.
 
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fs454

macrumors 68000
Dec 7, 2007
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What, you use your headphones as an audio source? Tell us more...

The built in microphone on most Bose headphones is just like the one on EarPods. Seems that the 3.5mm jack can accept that type of mic input, so it must have some input capability on the hardware side.
 

shoeshine

macrumors member
Original poster
Feb 27, 2010
46
0
thanks for the tips here. I did notice that my headset with mic and earbuds works ok, but I was hoping to be able to plug in a stereo line level input, which its sounding like is no longer possible. For the most part been really happy with this 2016 MBP, but this is kinda annoying.
 

Chancha

macrumors 68020
Mar 19, 2014
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Trrs-applenonstandard.png

The iPhone uses a TRRS "standard" variant for 3.5mm jack which simply add an additional contact towards the bottom of the stem for the mono mic to run through. Apple then subsequently added that function onto all Macs since the iPhone, so that all the stock iDevice headset mics can be used on Macs as input as well, which is quite neat when there is only space for one jack.

On the MBP2016, for some reasons Apple decided to keep this ability, but took out completely the regular line level stereo input. This is one of the many puzzling decisions from Apple hardware wise, as this costs next to nothing to be implemented, does not waste space or battery, but its absence definitely hurts user experience. The only remote reason is to simplify the circuitry to minimize failure rates which only happens very rarely.
 

fs454

macrumors 68000
Dec 7, 2007
1,979
1,825
Los Angeles / Boston
Trrs-applenonstandard.png

The iPhone uses a TRRS "standard" variant for 3.5mm jack which simply add an additional contact towards the bottom of the stem for the mono mic to run through. Apple then subsequently added that function onto all Macs since the iPhone, so that all the stock iDevice headset mics can be used on Macs as input as well, which is quite neat when there is only space for one jack.

On the MBP2016, for some reasons Apple decided to keep this ability, but took out completely the regular line level stereo input. This is one of the many puzzling decisions from Apple hardware wise, as this costs next to nothing to be implemented, does not waste space or battery, but its absence definitely hurts user experience. The only remote reason is to simplify the circuitry to minimize failure rates which only happens very rarely.


Hmm. So is there a possibility to create an adapter cable that contacts the mic level input like a pair of inline mic-equipped headphones do, but then has a standard 3.5mm female input on the other side? Or is the headphone mic implementation limited in some way that would prevent this?

Just thinking out loud here. I figure some sort of inexpensive USB/TB interface would easily do the trick, but if input can be tapped out of the 3.5mm still there's gotta be value in that for some users/cases.
 

alFR

macrumors 68030
Aug 10, 2006
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The built in microphone on most Bose headphones is just like the one on EarPods. Seems that the 3.5mm jack can accept that type of mic input, so it must have some input capability on the hardware side.
I was being a bit facetious. :) Not stereo input though AFAIK?
 

Chancha

macrumors 68020
Mar 19, 2014
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Hmm. So is there a possibility to create an adapter cable that contacts the mic level input like a pair of inline mic-equipped headphones do, but then has a standard 3.5mm female input on the other side? Or is the headphone mic implementation limited in some way that would prevent this?

Just thinking out loud here. I figure some sort of inexpensive USB/TB interface would easily do the trick, but if input can be tapped out of the 3.5mm still there's gotta be value in that for some users/cases.
s-l1600.jpg

They exist, Google "TRRS splitter cable" and you will get thousands of options.

Though the problems of such setup are obvious:
- it is only mono input on one end and stereo output on the other
- it is mic level
- the contacts are usually cheaply made, and even if it was not, there are still more places to get possible distortion / interference
- when split, analog signal strength is halved

So this is only a makeshift solution for chatting over mic, not one for music which a regular AUX line in can easily do. In the long run, a digital interface such as a dongle sized USB DAC / mic-pre is more ideal. The MBP dongle situation is a real struggle lol.
 

fs454

macrumors 68000
Dec 7, 2007
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1,825
Los Angeles / Boston
s-l1600.jpg

They exist, Google "TRRS splitter cable" and you will get thousands of options.

Though the problems of such setup are obvious:
- it is only mono input on one end and stereo output on the other
- it is mic level
- the contacts are usually cheaply made, and even if it was not, there are still more places to get possible distortion / interference
- when split, analog signal strength is halved

So this is only a makeshift solution for chatting over mic, not one for music which a regular AUX line in can easily do. In the long run, a digital interface such as a dongle sized USB DAC / mic-pre is more ideal. The MBP dongle situation is a real struggle lol.

Hmm, I see these portable iOS filming / news gathering rigs use this all the time actually and have heard of great results. I didn't realize they were hooking microphones up through the 3.5mm jack, but they are:
17127251_1838509883068949_6150659262570823680_n.jpg


Most line in microphones are mono anyways (like the Rode Videomic Pro pictured above) and I'd bet the input circuitry on Apple devices is better than the average audio preamps in a consumer Canon DSLR which are for the most part pretty awful. I'd be willing to bet one could achieve a pretty clean input of a guitar or other single channel input device with the right cable.
 

Chancha

macrumors 68020
Mar 19, 2014
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It is definitely possible to get clean feeds from TRRS cabling, but the sheer luck involved in having "the right cable" is the problem. I have a hard time imagining your pictured setup, as portable as it looks, could stand the constant jiggling and impact of the action shooting sequences without some clicks here and there. Professional audio hardware use XLR for a reason.

But back to the point, the presence of a mono input out of a single 3.5mm jack that's meant for output is indeed convenient, and in some case life saving. It makes otherwise impossible I/O setup doable on particular devices when you don't have a lot of specific external gears or space available.
 

musique

macrumors regular
Apr 10, 2009
222
5
'm plugging in a stereo 3.5mm plug from a line out from a mixer.

You don't mention much about your set-up and use but I'm assuming you're capturing live audio. Many external (stand-alone) mixers have pretty good DACs (digital/audio converters) in them.

Are you using the direct line in from the microphone(s) to the line out of the mixer? (If not, then you might be converting an analog signal to a digital signal twice -- once in the mixer and again in the Mac -- which can degrade the final audio.)

Most quality mixers will have one of more digital outputs so you might be better using a USB out on the mixer and getting a dongle (USB to USB-C converter). This would be especially true if you're using good microphones (often with XLR connectors).
 

Fishrrman

macrumors Penryn
Feb 20, 2009
28,348
12,464
If you need stereo "in", you're going to have to do it via USB.

For mono, it -might- be possible to jerry-rig a cable that works, but again, the best "way in" is probably through the USB port.
 
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