trying to make an audio loopback/antenna cable for FM recording...

B

Bob F

Guest
I have been trying to get my Galaxy S9 to record FM radio programs.
NextRadio is the only app that I have gotten to work to receive FM using
the internal tuner, but it has no record capability.

I have the app Audio Recorder loaded, which works for a headphone/w
microphone well, but does not work with the Recording Source set to
internal audio with the NextRadio app, which I had hoped would work.

So, I am trying to make a cable from a 4 wire TRRS audio cable that can
plug into the phone, acting as the FM antenna, and feed reduced signal
from the audio outputs from the phone into the microphone signal input
to the phone.

I used a 29.5 inch length of the audio cable with the TRRS male plug at
one end, and built the following circuit at the other end, hoping the
would signal the phone that it has earphones and a microphone connected
to the phone so Audio Recorder can record from the back fed headphone
output.

https://source.android.com/docs/core/audio/latency/loopback

Unfortunately, this is not working. It seems the phone is not detecting
the signal coming in as an external mic, and picks up the intern phone
mic instead. My understanding is that the phone looks for the impedance
of a mic to make the switch, and it seem the resisters in the above
circuit is not causing that to happen.

If anyone has knowledge about what the phone expects to make the mic
switch, I can definitely use some help. A record app that can force
external mic switching could be a solution. A FM radio program that can
use internal audio or that has built in record function that will work
on the S9 could also be my solution.
 
On 1/14/2023 2:17 PM, Bob F wrote:
I have been trying to get my Galaxy S9 to record FM radio programs.
NextRadio is the only app that I have gotten to work to receive FM using
the internal tuner, but it has no record capability.
snip...
Click to expand...

I have no idea about your problem but I\'m gobsmacked that a phone has an
external microphone input. I\'ve never seen or heard of such a thing.
 
On 1/14/2023 1:03 PM, Bodger wrote:
On 1/14/2023 2:17 PM, Bob F wrote:
I have been trying to get my Galaxy S9 to record FM radio programs.
NextRadio is the only app that I have gotten to work to receive FM
using the internal tuner, but it has no record capability.
snip...

I have no idea about your problem but I\'m gobsmacked that a phone has an
external microphone input. I\'ve never seen or heard of such a thing.
Click to expand...

It is the same jack that you plug headphones into. Completely compatible
with headphones that include a mic with a 4 conductor TRRS plug. I think
that is pretty common.

I should add to the original post that my OS is updated to Android 10,
G960UTUES9FVD1.
 
On 2023-01-14 22:03, Bodger wrote:
On 1/14/2023 2:17 PM, Bob F wrote:
I have been trying to get my Galaxy S9 to record FM radio programs.
NextRadio is the only app that I have gotten to work to receive FM
using the internal tuner, but it has no record capability.
snip...

I have no idea about your problem but I\'m gobsmacked that a phone has an
external microphone input. I\'ve never seen or heard of such a thing.
Click to expand...

All phones that have a connector for external earphones on cable, that
same connector and cable have provision for a microphone.

--
Cheers, Carlos.
 
On 1/14/2023 4:25 PM, Bob F wrote:
On 1/14/2023 1:03 PM, Bodger wrote:
On 1/14/2023 2:17 PM, Bob F wrote:
I have been trying to get my Galaxy S9 to record FM radio programs.
NextRadio is the only app that I have gotten to work to receive FM using
the internal tuner, but it has no record capability.
snip...

I have no idea about your problem but I\'m gobsmacked that a phone has an
external microphone input. I\'ve never seen or heard of such a thing.


It is the same jack that you plug headphones into. Completely compatible
with headphones that include a mic with a 4 conductor TRRS plug. I think
that is pretty common.

I should add to the original post that my OS is updated to Android 10,
G960UTUES9FVD1.
Click to expand...

OK, now that makes sense. Somehow my mind jumped to the image of a separate
microphone input. Probably some gray cells are winking out from lack of use...
 
On Saturday, January 14, 2023 at 5:29:13 PM UTC-6, Bodger wrote:
On 1/14/2023 4:25 PM, Bob F wrote:
On 1/14/2023 1:03 PM, Bodger wrote:
On 1/14/2023 2:17 PM, Bob F wrote:
I have been trying to get my Galaxy S9 to record FM radio programs.
NextRadio is the only app that I have gotten to work to receive FM using
the internal tuner, but it has no record capability.
snip...

I have no idea about your problem but I\'m gobsmacked that a phone has an
external microphone input. I\'ve never seen or heard of such a thing.


It is the same jack that you plug headphones into. Completely compatible
with headphones that include a mic with a 4 conductor TRRS plug. I think
that is pretty common.

I should add to the original post that my OS is updated to Android 10,
G960UTUES9FVD1.
OK, now that makes sense. Somehow my mind jumped to the image of a separate
microphone input. Probably some gray cells are winking out from lack of use...
Click to expand...

A signal always travels from its output to its input as long as the rules of proper
power and impedance are followed along the way- kind of like a glorified postal
system, from a conceptual sense.

The headphone jack can be use as a variable audio output jack when using a patch
cord or Y-adapter patch cable from that device to an RCA audio R/L audio input on
an analog recording device (converting the impedance from an 1/8\" (3.5 mm) jack
at 32 ohms to an RCA jack at 1000 ohms) which leads up to an analog device.

Or you can use an 1/8\" male to male patch cable to go to a computer line input or
other similar device to convert the signal to a digital sampler (starting out as analog
and then getting converted to a digital media in the processing). You have to remember
level control is also very important. Don\'t overload the headphone outs with \"too much\"
signal (or distortive audio) or avoid overdriving the signal.

Good Luck.

Charles Lucas
 
On 1/18/2023 9:15 AM, Charles Lucas wrote:
On Saturday, January 14, 2023 at 5:29:13 PM UTC-6, Bodger wrote:
On 1/14/2023 4:25 PM, Bob F wrote:
On 1/14/2023 1:03 PM, Bodger wrote:
On 1/14/2023 2:17 PM, Bob F wrote:
I have been trying to get my Galaxy S9 to record FM radio programs.
NextRadio is the only app that I have gotten to work to receive FM using
the internal tuner, but it has no record capability.
snip...

I have no idea about your problem but I\'m gobsmacked that a phone has an
external microphone input. I\'ve never seen or heard of such a thing.


It is the same jack that you plug headphones into. Completely compatible
with headphones that include a mic with a 4 conductor TRRS plug. I think
that is pretty common.

I should add to the original post that my OS is updated to Android 10,
G960UTUES9FVD1.
OK, now that makes sense. Somehow my mind jumped to the image of a separate
microphone input. Probably some gray cells are winking out from lack of use...

A signal always travels from its output to its input as long as the rules of proper
power and impedance are followed along the way- kind of like a glorified postal
system, from a conceptual sense.

The headphone jack can be use as a variable audio output jack when using a patch
cord or Y-adapter patch cable from that device to an RCA audio R/L audio input on
an analog recording device (converting the impedance from an 1/8\" (3.5 mm) jack
at 32 ohms to an RCA jack at 1000 ohms) which leads up to an analog device.

Or you can use an 1/8\" male to male patch cable to go to a computer line input or
other similar device to convert the signal to a digital sampler (starting out as analog
and then getting converted to a digital media in the processing). You have to remember
level control is also very important. Don\'t overload the headphone outs with \"too much\"
signal (or distortive audio) or avoid overdriving the signal.
Click to expand...

I tried a half dozen recording apps to try to record the NextRadio audio
from the headphone jack back at a lower level into the mic input. One of
them \"Voice recorder\" 21.3.55.16, causes NextRadio to stop
receiving/outputting the FM audio while it is recording.

The other recording apps I tried would let NextRadio keep going, but the
app shows zero signal, so no audio gets recorded.

I tried a couple of the apps while playing an mp3 file on the phone, and
the audio was recorded properly.

So, it really seems like NextRadio is doing something wierd to prevent
recording of it\'s output.

Can anyone propose what they might be doing, or ways to get past it.

I cannot find any other FM apps that will run on my S9.
 
On Friday, January 20, 2023 at 10:51:04 PM UTC-6, Bob F wrote:
On 1/18/2023 9:15 AM, Charles Lucas wrote:
On Saturday, January 14, 2023 at 5:29:13 PM UTC-6, Bodger wrote:
On 1/14/2023 4:25 PM, Bob F wrote:
On 1/14/2023 1:03 PM, Bodger wrote:
On 1/14/2023 2:17 PM, Bob F wrote:
I have been trying to get my Galaxy S9 to record FM radio programs.
NextRadio is the only app that I have gotten to work to receive FM using
the internal tuner, but it has no record capability.
snip...

I have no idea about your problem but I\'m gobsmacked that a phone has an
external microphone input. I\'ve never seen or heard of such a thing.


It is the same jack that you plug headphones into. Completely compatible
with headphones that include a mic with a 4 conductor TRRS plug. I think
that is pretty common.

I should add to the original post that my OS is updated to Android 10,
G960UTUES9FVD1.
OK, now that makes sense. Somehow my mind jumped to the image of a separate
microphone input. Probably some gray cells are winking out from lack of use...

A signal always travels from its output to its input as long as the rules of proper
power and impedance are followed along the way- kind of like a glorified postal
system, from a conceptual sense.

The headphone jack can be use as a variable audio output jack when using a patch
cord or Y-adapter patch cable from that device to an RCA audio R/L audio input on
an analog recording device (converting the impedance from an 1/8\" (3.5 mm) jack
at 32 ohms to an RCA jack at 1000 ohms) which leads up to an analog device.

Or you can use an 1/8\" male to male patch cable to go to a computer line input or
other similar device to convert the signal to a digital sampler (starting out as analog
and then getting converted to a digital media in the processing). You have to remember
level control is also very important. Don\'t overload the headphone outs with \"too much\"
signal (or distortive audio) or avoid overdriving the signal.

I tried a half dozen recording apps to try to record the NextRadio audio
from the headphone jack back at a lower level into the mic input. One of
them \"Voice recorder\" 21.3.55.16, causes NextRadio to stop
receiving/outputting the FM audio while it is recording.

The other recording apps I tried would let NextRadio keep going, but the
app shows zero signal, so no audio gets recorded.

I tried a couple of the apps while playing an mp3 file on the phone, and
the audio was recorded properly.

So, it really seems like NextRadio is doing something wierd to prevent
recording of it\'s output.

Can anyone propose what they might be doing, or ways to get past it.

I cannot find any other FM apps that will run on my S9.
Click to expand...

I repeated this message for the benefit of all concerned.

We never addressed the software you use. Some software is not licensed to pickup signals
for recording because they want you to pay money for that. You can download several
free audio recording or dubbing software apps, record in .mp3 at the desired rate, and
then copy and paste the completed file over to NextRadio\'s output folder for audio so
you can play it back.

Or you can record it in 16 bit Stereo wave format (.wav) file, convert it to .mp3 format
you desire to convert it to with a convertor. Then dump the file into NextRadio\'s
output folder to playback the finished .mp3 file. In this way, you can bypass the
software you speak of stringent requirements and pedantic quirks.

FYI, sometimes, there is a DRM (Digital Rights Management) on these files or software
that play them to prohibit copying copywritten files. DRM is a form of a \"copy\" guard,
again because it boils down to the fact that they want you to pay money to get the
composite signal that comes from them. I just provided you work arounds without
the cost and the hassle; I also warn that this post is for educational purposes only
regarding recording and conversion of signal and is not an encouragement to violate
any copyright or infringe upon anyone\'s work in any other form otherwise.

Good luck,

Charles Lucas
 
On 1/23/2023 9:35 AM, Charles Lucas wrote:
On Friday, January 20, 2023 at 10:51:04 PM UTC-6, Bob F wrote:
On 1/18/2023 9:15 AM, Charles Lucas wrote:
On Saturday, January 14, 2023 at 5:29:13 PM UTC-6, Bodger wrote:
On 1/14/2023 4:25 PM, Bob F wrote:
On 1/14/2023 1:03 PM, Bodger wrote:
On 1/14/2023 2:17 PM, Bob F wrote:
I have been trying to get my Galaxy S9 to record FM radio programs.
NextRadio is the only app that I have gotten to work to receive FM using
the internal tuner, but it has no record capability.
snip...

I have no idea about your problem but I\'m gobsmacked that a phone has an
external microphone input. I\'ve never seen or heard of such a thing.


It is the same jack that you plug headphones into. Completely compatible
with headphones that include a mic with a 4 conductor TRRS plug. I think
that is pretty common.

I should add to the original post that my OS is updated to Android 10,
G960UTUES9FVD1.
OK, now that makes sense. Somehow my mind jumped to the image of a separate
microphone input. Probably some gray cells are winking out from lack of use...

A signal always travels from its output to its input as long as the rules of proper
power and impedance are followed along the way- kind of like a glorified postal
system, from a conceptual sense.

The headphone jack can be use as a variable audio output jack when using a patch
cord or Y-adapter patch cable from that device to an RCA audio R/L audio input on
an analog recording device (converting the impedance from an 1/8\" (3.5 mm) jack
at 32 ohms to an RCA jack at 1000 ohms) which leads up to an analog device.

Or you can use an 1/8\" male to male patch cable to go to a computer line input or
other similar device to convert the signal to a digital sampler (starting out as analog
and then getting converted to a digital media in the processing). You have to remember
level control is also very important. Don\'t overload the headphone outs with \"too much\"
signal (or distortive audio) or avoid overdriving the signal.

I tried a half dozen recording apps to try to record the NextRadio audio
from the headphone jack back at a lower level into the mic input. One of
them \"Voice recorder\" 21.3.55.16, causes NextRadio to stop
receiving/outputting the FM audio while it is recording.

The other recording apps I tried would let NextRadio keep going, but the
app shows zero signal, so no audio gets recorded.

I tried a couple of the apps while playing an mp3 file on the phone, and
the audio was recorded properly.

So, it really seems like NextRadio is doing something wierd to prevent
recording of it\'s output.

Can anyone propose what they might be doing, or ways to get past it.

I cannot find any other FM apps that will run on my S9.

I repeated this message for the benefit of all concerned.

We never addressed the software you use. Some software is not licensed to pickup signals
for recording because they want you to pay money for that. You can download several
free audio recording or dubbing software apps, record in .mp3 at the desired rate, and
then copy and paste the completed file over to NextRadio\'s output folder for audio so
you can play it back.
Click to expand...

No need to play it back using NextRadio. I just want to be able to
capture the sound from it. I tried a half dozed audio capture apps, and
none of them can capture the internal audio from NextRadio, or the
reduced signal sent out the earphones and fed back (reduced) into the
external mic input with. I even tried using a headphone with a mic, and
taping one of the earpieces to the mic rather than resisters and a cap
to feed the signal back, and neither one works.

One of the recorder apps shuts off the NextRadio output when recording,
the others just have 0 volume input despite the signal going into the
external mic input, or they just record whatever the internal mic hears.

Or you can record it in 16 bit Stereo wave format (.wav) file, convert it to .mp3 format
you desire to convert it to with a convertor. Then dump the file into NextRadio\'s
output folder to playback the finished .mp3 file. In this way, you can bypass the
software you speak of stringent requirements and pedantic quirks.

FYI, sometimes, there is a DRM (Digital Rights Management) on these files or software
that play them to prohibit copying copywritten files. DRM is a form of a \"copy\" guard,
again because it boils down to the fact that they want you to pay money to get the
composite signal that comes from them. I just provided you work arounds without
the cost and the hassle; I also warn that this post is for educational purposes only
regarding recording and conversion of signal and is not an encouragement to violate
any copyright or infringe upon anyone\'s work in any other form otherwise.

Good luck,

Charles Lucas
Click to expand...
 
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