Question using pc as an external audio input/output source for android smartphone

[dzyang94]

I was replying to an 2018 thread by mltco78dhs but by the time i finished writing it became "solved", with the "solution" being "nope you can't do that duh" and i thought that's not good enough.

the original discussion was about if using pc as an external audio input/output source for android smartphone possible. there was also a new reply (when i saw it, it said posted 5 minutes ago) but it got deleted and the thread marked solved. well guess what mods it IS possible and i have solved half of the puzzle!

my result so far:
i was able to pass phone audio to pc. but i could not pass audio from pc to phone.

what i used:
type-c to 3.5mm cord x1
3.5mm splitter x1
usb gaming headphones with mic x1

what i did:
step 1. connect type-c to phone, 3.5mm to splitter, and splitter normally to pc. phone will recognize that headphones has been plugged in (my phone shows a small headphones symbol at the top of the screen).
step 2. now unplug the splitter from pc and switch them around, plug it back in.
step 3. on pc open sound settings and open property for default microphone, tick "listen to device", and use usb headphones as listen output.
step 4. make a sound on phone (open a video, play music etc), and will hear it on usb headphones.

what isn't right:
theoretically, now tick "listen to device" for mic on usb headphones and use default speaker as listen output everything should work, but it doesn't. instead my phone could not receive any audio from my pc. Also, my mic is being force-fed back into usb headphones, with no ways to turn it off.

c'mon guys i feel i'm so close!!! all ideas welcome to complete the final step!

 

[fogyreef]

I chatted with Samsung, who said recording from PC to Phone won't work. The hardware doesn't support it.

However, it does support hooking up an external mic. I have a saramonic USB C mic, and it records. The problem is it sounds like crap as it picks up all the ambient noise.

So the next step for us is to figure out how to hotwire the signal from the PC to the external Mic and trojan horse it. Before I start cannibalizing my cables I want to know if people out there know what to do.

For example, matching the signal strength between stereo out and mic in; is that a thing?

I have a 3.5mm TRS to TRRS adapter. (referring to the rings on your 3.5mm jacks, where stereo is Tip Ring Sleeve (TRS) and stereo with mic is TRRS with an extra ring for the mic). Does the adapter connect the stereo signals to the mic and pass them along?

How do we do this?

 

[Luckybob]

I chatted with Samsung, who said recording from PC to Phone won't work. The hardware doesn't support it.
However, it does support hooking up an external mic. I have a saramonic USB C mic, and it records. The problem is it sounds like crap as it picks up all the ambient noise.

So the next step for us is to figure out how to hotwire the signal from the PC to the external Mic and trojan horse it. Before I start cannibalizing my cables I want to know if people out there know what to do.
For example, matching the signal strength between stereo out and mic in; is that a thing?

I have a 3.5mm TRS to TRRS adapter. (referring to the rings on your 3.5mm jacks, where stereo is Tip Ring Sleeve (TRS) and stereo with mic is TRRS with an extra ring for the mic). Does the adapter connect the stereo signals to the mic and pass them along?
How do we do this?

Hi!
What you guys are trying to achieve, in right on point with the testings on my side. Unfortunately, didn't find any way to make it work. But I'll still detail what I tried, so that anyone willing to push it further, would have - to try out.

🤞Goal : Transforming the Direct Monitoring Output of the Focusrite into a Mic input (so that I don't need any numerical compatibility between devices, such as USB, drivers, etc), allowing to use any mix plugged into the interface, including 48V/Phantom power ones, on any device, 100% analogically.
Of course, I came to that idea, since I couldn't make the USB interface work on the smartphone, for every mic usage, notably rec & calls. Couldn't use apps through Windows PC either; the "My phone" Windows App was supposed to allow that, but it never worked for me & seems so unreliable anyway (Force close all the time, ppl saying it cancels calls randomly...); Samsung Dex is also an app very close from achieving it (it probably could in the future?), but the feature is just not available, only audio Phone→PC is supported... & I don't want wireless apps like Airdroid, wire = no data spying, best quality + reliability, - battery drains, & no Wi-Fi required in order to work (I actually have no Wi-Fi 😅)...

👉 Material :
♦ Focusrite Scarlett USB Interface, with XLR 48V mic
♦ Android phone (Galaxy S10e), with 3.5 hp jack ; High Res Audio Recorder & Call apps
♦ TRS & TRRS 3.5 male² cables ; TRS cable cut on 1 hand for experiments
♦ This TRRS screwable adapter: https://www.amazon.fr/gp/product/B08CVM2T31
♦ this Male TRS ↔ Female TRRS adapter for mics: https://www.ebay.com/itm/3-5mm-3-Po...icrophone-Jack-converter-Adapter/224045325396 (converts TRRS mics like SmartLav+ into TRS mics, making them compatible with smartphones → cameras) ; equivalent to the Rode adpter : https://www.ebay.fr/itm/Replacement...e-TRRS-to-3-5mm-TRS-Male-Adapter/224088834243
♦ This TRRS Mic/Hp splitter: https://www.ebay.com/itm/Ugreen-Hea...Cable-3-5mm-Male-to-2-Female-PS4/152594143413
♦ OMTP/CTIA converter: https://www.ebay.com/itm/3-5mm-Jack...tal-Male-to-Female-Audio-Adapter/324299553568

👇Experiments : [Spoiler: All FAILED 😭]
I mean, hold on... no, hang on!
→ Plugging the splitter to the phone, & the USB interface to the PC for power & tests, will be all along the tests; keep in mind the splitter makes the mic signal equivalent to a TRRS mic, when it comes to which pole transfers the signal (Sleeve).
→ As a contextual validation: Smartlav+ Rode mic → [Male TRS ↔ Female TRRS adapter for mics] → Splitter on mic side→ Smartphone : 🍾WORKS✅ 🍾(redundancy of TRRS→TRS→TRRS)

• Interface output → OMTP/CTIA converter → TRS Male² cable → Splitter on mic side → Smartphone : Fail
• Interface output → TRS Male² cable → OMTP/CTIA converter → Splitter on mic side : Fail
• Interface output → TRS Male² cable → [Male TRS ↔ Female TRRS adapter for mics] → Splitter on mic side : Fail
• Interface output → [Male TRS ↔ Female TRRS adapter for mics] (reversed)→ TRS Male² cable → Splitter on mic side : Fail
• Interface output → OMTP/CTIA converter → TRS Male² cable → [Male TRS ↔ Female TRRS adapter] → Splitter on mic side : Fail
• Interface output → OMTP/CTIA converter → [Male TRS ↔ Female TRRS adapter] (reversed)→ TRS Male² cable → Splitter on mic side : Fail
• Interface output → TRS Male² cable → OMTP/CTIA converter → [Male TRS ↔ Female TRRS adapter] → Splitter on mic side : Fail
• Interface output → [Male TRS ↔ Female TRRS adapter] (reversed) → OMTP/CTIA converter→ TRS Male² cable → Splitter on mic side : Fail
• Interface output → TRS Male² cable → [Male TRS ↔ Female TRRS adapter] → OMTP/CTIA converter → Splitter on mic side : Fail
• Interface output → [Male TRS ↔ Female TRRS adapter] (reversed)→ TRS Male² cable → OMTP/CTIA converter → Splitter on mic side : Fail

• Plugging TRRS Male² cable didn't change anything from TRRS, since the interface output is TRS, so discard this option right away. Just wanted to try in case voodoo stuff would happen 😇
• Partially insert of jacks, in all previous cases: Fail; the app stopped recordings most of the time, as it does when a mic is unplugged, bc it "fake-detected" 1 in & out. Yet, I remember & of these tests gave a successful signal while unplugging, but not on a steady position! Which gave me the hope it would work on below experiments...

→ Now, I was convinced the solution hinged on building a custom cable, as it might be a matter of ground placement/commuting/shunted...
→ My TRS cable cut on 1 hand for experiments, gave me 5 headaches, just to figure out which wire was what, since it had 5 non standard colored wires... By trying & error, found out the L, R, & all the others considered as Ground, so joined together.
→ Now, on the TRRS screwable adapter: considere the correct wiring (for TRS cable) is: L wire ↔ T ; R wire ↔ R1 ; Ground ↔ R2 ; Ø ↔ S
→ For tests, L & R are reversible, since it's just a matter of signal/ø ; what could eventually make a difference in term of power/current/resistance (then detectability?) was L+R.

• Plugging (screwing) L, R & Ground properly (verified working), creating a straight TRS cable : Fail (of c, otherwise none of that would be necessary...)
• L wire ↔ T : Fail
• R wire ↔ R1 : Fail
• L wire ↔ T ; Ground ↔ R2 : Fail
• R wire ↔ R1 ; Ground ↔ R2 : Fail
• L wire ↔ T ; R wire ↔ R1 ; Ground ↔ S : Fail
• L wire ↔ T ; R wire ↔ R1 ; Ground ↔ R2 + S (Shunted) : Fail
• L + R wires ↔ R1 ; Ground ↔ R2 : Fail
• L + R wires ↔ R1 ; Ground ↔ R2 + S : Fail
• L wire ↔ T ; R wire ↔ R1 : Fail
• L wire ↔ T ; Ground ↔ R1 : Fail
• R wire ↔ R1 ; Ground ↔ T : Fail
• L wire ↔ T ; R wire ↔ R1 ; Ground ↔ : Fail
• L wire ↔ T ; Ground ↔ R1 + R2 + S : Fail
• L wire ↔ R1 ; Ground ↔ T + R2 + S : Fail

Conclusion: I'm officially utterly PISSED OFF If none of those worked, the only remaining explaination to me, is there is some difference between Mic in & any device output. But can't figure out which one.. Power? Couldn't try every step on the potentiometer obviously, but nor 0, nor low, neither high gain did change a thing. Resistance? I tend to think so.

👉 "So the next step for us is to figure out how to hotwire the signal from the PC to the external Mic and trojan horse it " 👍, PC being USB interface's monitor output in my case (even though having the signal going through the PC is appliable as well). Any TRS output basically.
Thx for the input guys, hope it was complementary, or as a confirmation (of failure though). 😄💀