You are here

Mono cable to stereo jack

All about the tools and techniques involved in capturing sound, in the studio or on location.

Moderator: Moderators

Mono cable to stereo jack

Postby csarami@ncsu.edu » Tue Mar 02, 2021 4:16 pm

Hi,

I am setting up a mix-minus with my Yamaha MG USB mixer and iPhone X. I was wondering if I connect my phone's stereo out to my mixer mono input channel :

1) mono to mono 1/8 to 1/4", iPhone to mixer respectively.
2) stereo to stereo 1/8" to 1/8" but connected to the mixer via 1/8 to 1/4" adaptor.

Which one carries a true mono (L+R) output of the iPhones?

Any help would be appreciated.

PS. I am using a Y splitter to split the microphone and stereo out from my iPhone X.
csarami@ncsu.edu
Regular
Posts: 86
Joined: Thu May 25, 2017 1:44 pm

Re: Mono cable to stereo jack

Postby The Elf » Tue Mar 02, 2021 4:39 pm

What you need is an 1/8 inch stereo jack to a pair of mono 1/4 inch jacks. You will need to plug both of the 1/4 jacks into two channels of your mixer (and pan the channels fully Left and Right) to get a true stereo output from your phone. If you use only one of the 1/4 jacks you will be hearing only one side of the stereo feed, which may be OK, but anything fully panned to the side you have left unplugged will not be heard.
Image
User avatar
The Elf
Jedi Poster
Posts: 16565
Joined: Tue Aug 14, 2001 12:00 am
Location: Sheffield, UK
An Eagle for an Emperor, A Kestrel for a Knave.

Re: Mono cable to stereo jack

Postby Hugh Robjohns » Tue Mar 02, 2021 5:09 pm

Phones use a four-pole TRRS connector to pass a stereo headphone output and a mono mic input.

So the first thing you need is a proper TRRS to dual TRS (3.5mm) splitter lead to access the various signal connections.

The stereo headphone outputs need to be connected to two mono channels of the mix and panned hard left/right if you plan on playing stereo material from the phone. If you are only going to be using mono signals (eg. phone calls) then you need only connect one channel and pan it centrally.

DO NOT use a TRS-TRS adapter to connect the stereo headphone signal to a balanced mono input channel, as you won't hear anything (the identical left and right channels will be cancelled out by the differential input)!

The mic-minus or clean-feed output from the mixer (most easily derived using Aux sends) needs to be sent back to the phone splitter's unbalanced mic input minijack connection and some experimentation will be needed to optimise the signal level.
User avatar
Hugh Robjohns
Moderator
Posts: 30663
Joined: Fri Jul 25, 2003 12:00 am
Location: Worcestershire, UK
Technical Editor, Sound On Sound
In my world, things get less strange when I read the manual... 

Re: Mono cable to stereo jack

Postby The Elf » Tue Mar 02, 2021 5:21 pm

Oops - missed the bit about using a mic connection!
User avatar
The Elf
Jedi Poster
Posts: 16565
Joined: Tue Aug 14, 2001 12:00 am
Location: Sheffield, UK
An Eagle for an Emperor, A Kestrel for a Knave.

Re: Mono cable to stereo jack

Postby blinddrew » Tue Mar 02, 2021 5:29 pm

Hugh Robjohns wrote:Phones use a four-pole TRRS connector to pass a stereo headphone output and a mono mic input.

So the first thing you need is a proper TRRS to dual TRS (3.5mm) splitter lead to access the various signal connections.
Umm, Hugh, iphones haven't had a TRRS socket for a while now...
The OP has a microphone/headphone splitter (presumably with an iphone plug at the other end) already so we are just dealing with a stereo out on a 3.5mm TRS socket.
User avatar
blinddrew
Jedi Poster
Posts: 14203
Joined: Sun Jul 05, 2015 12:00 am
Location: York
Ignore the post count, I have no idea what I'm doing...

Re: Mono cable to stereo jack

Postby Hugh Robjohns » Tue Mar 02, 2021 6:34 pm

blinddrew wrote:Umm, Hugh, iphones haven't had a TRRS socket for a while now...

Ah yes... I don't frequent the Apple world and had forgotten that they had chosen to invent a connection format incompatible with everyone else...

The OP has a microphone/headphone splitter (presumably with an iphone plug at the other end) already so we are just dealing with a stereo out on a 3.5mm TRS socket.

So the same principles apply regarding the need to split the stereo unbalanced 3.5mm TRS headphone feed into two TS quarter-inch plugs for the mixer inputs.

And then something to take the mixer Aux out back to the adapter's mic input (quarter-inch TS to 3.5mm TS?)

BTW, Saramonic make some quite nice interfaces for Lightening and TRRS-equipped phones for mic and instrument inputs in mono and stereo, eg.: https://www.saramonicuk.com/products/saramonic-smartrig-uc-mic-guitar-interface-usb-c
User avatar
Hugh Robjohns
Moderator
Posts: 30663
Joined: Fri Jul 25, 2003 12:00 am
Location: Worcestershire, UK
Technical Editor, Sound On Sound
In my world, things get less strange when I read the manual... 

Re: Mono cable to stereo jack

Postby csarami@ncsu.edu » Tue Mar 02, 2021 11:25 pm

Thank you everyone for the great inside. I just made my purchase!

I have several of those Apple Lightning to female TRSS adaptors.

[img height =300]https://i.ebayimg.com/images/g/pBwAAOSw-Adfpf9K/s-l1600.jpg[/img]

I need to review some cable information. There are so many cables now. The cable industry is booming and is huge!

TRS, TRRS, TRS cables balanced or unbalanced, XLR, USB-X, ...
csarami@ncsu.edu
Regular
Posts: 86
Joined: Thu May 25, 2017 1:44 pm