Aux in question

Posted by: russell

Aux in question - 03/08/2004 16:27

Is it possible ( with or with out any coding) to use either the microphone input or the audio in meant for the tuner at the same time as either the player or the Aux in source.

I would like to connected my iPaq up and have it's sound played over the top of the normal player output. at a constant volume independent of the players volume control.

The plan is to run Sat Nav on the Ipaq with the audio directions mixed in with the normal player output, but so that i can turn down the player and still have the directions at the same volume.

Any ideas?

Thanks
Russell
Posted by: pgrzelak

Re: Aux in question - 03/08/2004 16:32

There is nothing (to my knowledge) in the existing player software that will let you mix the audio sources. I think that the DSP might be able to do it, but it will require specialized coding.

...an iPod...
Posted by: tfabris

Re: Aux in question - 03/08/2004 16:37

What you're describing can be done much simpler, easier, and more reliable, with a simple resistance mixer circuit, after the output of the empeg and before the amplifier.

The external mixer circuit would also meet your criteria of wanting the directions from the IPAQ playing at a constant volume if you turn down the player volume. Doing it in software with the aux or mic inputs would mean the ipaq gets turned down with the empeg.

There is currently no software to do what you want, and a lot of coding work would be required to do that job. So it would be a while (if ever) before you were able to do what you want in software. The external mixer circut, on the other hand, could be done right away.

Anyone have a link to a schematic for a simple mixer circuit?

On the other hand, a generic "blend" feature, taking the mic, aux, or Tuner audio inputs, sampling them and blending them with the output, would be totally cool for posterity, and for other projects like this. Wonder if that's something that could be built into hijack? Dunno which sub-permutations of that are even possible, there's some limitations in the DSP and you might not be able to sample the aux input at the same time as you're playing audio, for example. But you could probably do it with the mic input at least, if nothing else.
Posted by: wfaulk

Re: Aux in question - 03/08/2004 16:37

The audio overlay patch is in Hijack these days, IIRC. I don't know how it works, nor do I know if the volume is separate or not. You'll definitely have to write your own app to deal with it. But it ought to be doable in some way.
Posted by: russell

Re: Aux in question - 03/08/2004 16:41

Well I've got next week off work, so who knows i may write my first Empeg app!. Does any one have any details about the Tuner inputs. i.e there pin out levels etc.

Regards
Russell
Posted by: snoopstah

Re: Aux in question - 05/08/2004 06:06

Quote:
What you're describing can be done much simpler, easier, and more reliable, with a simple resistance mixer circuit, after the output of the empeg and before the amplifier.

The external mixer circuit would also meet your criteria of wanting the directions from the IPAQ playing at a constant volume if you turn down the player volume. Doing it in software with the aux or mic inputs would mean the ipaq gets turned down with the empeg.

There is currently no software to do what you want, and a lot of coding work would be required to do that job. So it would be a while (if ever) before you were able to do what you want in software. The external mixer circut, on the other hand, could be done right away.

Anyone have a link to a schematic for a simple mixer circuit?

I'd be interested in this too (assuming a software solution is out of the question).
Posted by: andym

Re: Aux in question - 07/08/2004 18:50

I'd use something like this
Posted by: tfabris

Re: Aux in question - 10/08/2004 15:37

There's gotta be something simpler than that... We just want to combine two line-level RCA inputs into one...
Posted by: Yang

Re: Aux in question - 10/08/2004 19:37

Quote:
There's gotta be something simpler than that... We just want to combine two line-level RCA inputs into one...


You mean something like this? http://www.epanorama.net/circuits/linemixer.html

Not being an electrical guru, I don't know how easy or effective it is, but it looks simple enough..

And for the non electrical-inclinded, would this do the trick? http://www.wwbw.com/Rolls-MX42--Stereo-Mini--Mixer-i138112.music
Posted by: tfabris

Re: Aux in question - 10/08/2004 19:47

YES! A simple resistance mixer. That's exactly what I was talking about.

I'm going to save off that page.

Note that the page has an even more simplified version in ASCII at the bottom of the page. It mixes two line-level inputs equally without an adjustment.
Posted by: andym

Re: Aux in question - 14/08/2004 17:35

Quote:
There's gotta be something simpler than that... We just want to combine two line-level RCA inputs into one...


I dunno, I think I'd rather buffer them.
Posted by: schofiel

Re: Aux in question - 15/08/2004 19:47

So would I - unity gain, active line amplifiers would be far better than a simple resistive mixer. I'd go so far as to go and buy one rather than bodge it. At this point, pca will spring in with a design after about 20 seconds' thought (if that)....