I was surprised that the voltage coming out of the headset socket is probably not far off a line level (770mV rms across 600 ohms) which is why just a simple cable works OK.
If a camera has only a mike input, that’s going to be completely different especially if it is the “plug in power” electret mike sort of thing, which historically most camcorders had (all the Sony ones I had, for sure). Much more sensitive than line level. Plus you get the 4-pole jack plugs, etc.
Your audio sounds superb – I think I’d go as far as saying it’s the best I’ve ever heard.
Great! I won’t change a thing!
I have now tested my adaptor and it works great. It is much better that sticking a small microphone up the headset because all sound which doesn’t break the squelch on the radio(s) is totally suppressed, so you get proper silent silences, with zero engine noise. Only when the squelch is broken do you hear engine noise, which is then dependent on how good the noise compensating headset mikes are.
It’s clear – for the devices I record with – that the potentiometer is needed because at least one of them doesn’t have enough leeway in its level control to accept the an-attenuated signal.
This is a quick and dirty video I did yesterday
There are devices which don’t have a variable attenuator so the pot is really needed. For example my Pentax K3 DSLR, under its external record menu, has a “volume control” adjustment but it doesn’t seem to do anything to the record level, and just to make it more interesting it clips horribly even for a sound level which doesn’t reach anywhere near the peak on its level meter…
What will be interesting is whether the Samsung S6 phone (which I am looking at getting) will work with it. I am very sure it won’t because it has a mike input only, not a line input. It may mean that the only way will be to cut the speakers off the hands-free kit and glue the mike switch in the ON position – that is what I did on the Nokia 808.
I have a Samsung Galaxy S3 and it works with that kind of setup, although it only has a mic input. (Well, at least it is called a mic input.)
The cable I use (a Pilot Communications PA80i) could have series capacitors which might make a difference.
I get the feeling is that to feed a line level signal to the 3.5mm hands free kit jack socket, one merely needs to
Capacitors should not make a difference if the source is AC coupled but it’s a good point – you might otherwise end up shorting the mike power, although that should be going in through a resistor anyway.
Looking at the PA80i that’s all it can be…
