# Why don't smartphones have a line in recording facility like other computers?



## Hocus Eye. (Nov 16, 2011)

I have an app that will record good quality music from the built-in microphone, so I tried plugging a sound source into the headphone socket but it doesn't work. My laptop and all other computers have a line-in socket. Why can't smartphones have such a facility.

Or do some of them have this? I checked for an app that would do it but there isn't one. You can record off internet radio but no line-in. Somebody is going to tell me that the Simsing 55QZ that costs £600 has this feature I guess. I want to do it on my HTC Desire though.


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## joustmaster (Nov 16, 2011)

They can accept a mic input so I guess there is a way to do it.


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## elbows (Nov 16, 2011)

You can get this sort of thing for iPhones, I assume the same is true to a certain extent for some other phones. Some of the fancy iPhone versions use the special apple dock connector and are their own audio interface. But the 'normal' way to do it does involve the headphone socket. But you can't just plug a normal sound-source cable into that port, it needs to be a mic or adaptor that is designed to use the right pin on the jack (the same pin that a standard wired headphones & mic would use for the mic part).

You are probably in luck with the desire because here is someone testing 3 different miss with that phone:

http://audioboo.fm/boos/136565-mic-tests-for-htc-desire


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## Hocus Eye. (Nov 16, 2011)

elbows said:


> You can get this sort of thing for iPhones, I assume the same is true to a certain extent for some other phones. Some of the fancy iPhone versions use the special apple dock connector and are their own audio interface. But the 'normal' way to do it does involve the headphone socket. But you can't just plug a normal sound-source cable into that port, it needs to be a mic or adaptor that is designed to use the right pin on the jack (the same pin that a standard wired headphones & mic would use for the mic part).
> 
> You are probably in luck with the desire because here is someone testing 3 different miss with that phone:
> 
> http://audioboo.fm/boos/136565-mic-tests-for-htc-desire


Elbows thanks for that post. I checked out the link and could see that the guy had been using his ordinary headphone socket and headphones which I had not been able to do.

I had another go and fiddled about with the position of the jack plug while having a nearby radio turned on. After a bit of messing about I got my recording app to work! It seems that you have to pull the jack plug back a bit from being fully in.

The next thing is to try the same trick with a line-in when I can find the lead that I use with my computer. Thanks again.


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## elbows (Nov 16, 2011)

If you are talking about a normal audio jack then you probably won't succeed. The way that combined headphone & mic ports usually work is that there is an extra ring on the connector which is used for the mic part, and sometimes an additional ring for remote control.

So on a normal jack you will see 3 separate silver areas (2 black bands separating them), but one that has mic capability will have 4 separate areas as seen in the photo below. You can probably get an adaptor cable.

Also as you keep mentioning line-in rather than mic, you may also run into issues if the source you are trying to feed into the device is stereo rather than mono.


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## elbows (Nov 16, 2011)

The stuff Im going on about is also the reason why you've had to pull the plug out slightly to get normal headphones to work. The HTC is expecting more connections for remote & mic, so a normal headphone plug doesn't align perfectly with the connections inside the socket.

So for example the following adaptor is what is recommended to use normal headphones with your phone. What you ideally need is something like this but instead of a built-in mic, a socket to connect your own mic. Even then you may have an issue depending on what line-in source you are using (related to the stereo issue I mentioned earlier)

http://www.mobilefun.co.uk/htc-hs-u350-p19269.htm


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## Hocus Eye. (Nov 16, 2011)

elbows said:


> If you are talking about a normal audio jack then you probably won't succeed. The way that combined headphone & mic ports usually work is that there is an extra ring on the connector which is used for the mic part, and sometimes an additional ring for remote control.
> 
> So on a normal jack you will see 3 separate silver areas (2 black bands separating them), but one that has mic capability will have 4 separate areas as seen in the photo below. You can probably get an adaptor cable.
> 
> Also as you keep mentioning line-in rather than mic, you may also run into issues if the source you are trying to feed into the device is stereo rather than mono.


Yep got it. That jack plug is identical to my headphone one. I also have a stereo jack plug with only 2 sections and hence only two black separator rings. It have tested it as a line-out on the phone playing into my hi-fi and it works fine, so the socket must be compatible with both systems.

I don't need to do any of this I am just experimenting for its own sake.


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## elbows (Nov 16, 2011)

After some brief research it seems you might struggle a bit. Most of the devices I see have a built in mic.

At the other end of the spectrum you can get stuff like this for the iPhone, and it may work with other phones. Its got a balanced audio input for more pro microphones, guitars etc, rather than the simple 3.5mm jack for input, but the principal is the same.

http://tascam.com/product/ixz/


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