2 way crossover on Iriver?

[tehmalakai]

Heres the idea:

Analogue audio signal comes in the "line in" jack, two filters are applied digitally in real time: a high pass and a low pass.  The high pass signal goes to the headphone jack, and the low pass to the "line out" jack.  Crossover frequency and Q should be customizable, looking at the current parametric equalizer implementation, this shouldn't be a problem.

The only thing I can see stopping this from working is whether or not the headphone jack and line out can be given two different signals...

[saratoga]

The only thing I can see stopping this from working is whether or not the headphone jack and line out can be given two different signals...

I think the closest you could get would be to filter the L/R channels separately. 

Out of curiosity, why would want to do this?

[tehmalakai]

So are you saying that the headphone jack and line out are somehow hardwired together?  Yes splitting the left and right channels would work but then I would only be able to process a mono signal right?

Basically, I do sound setups for parties and stuff and my friend usually brings a nice hardware stereo crossover (because the subs need to be cutoff at around 200 hz, and the rest of the spectrum is sent to the mids and tops).  But I'm moving out of reach of him and am looking for a cheap alternative to buying a new crossover.

[saratoga]

So are you saying that the headphone jack and line out are somehow hardwired together?

Yes, these are low power devices, so they don't put extra DAC channels on there.  Putting more then 2 channels would waste power and not really serve any purpose since theres no 5.1 DAPs.

Basically, I do sound setups for parties and stuff and my friend usually brings a nice hardware stereo crossover (because the subs need to be cutoff at around 200 hz, and the rest of the spectrum is sent to the mids and tops).  But I'm moving out of reach of him and am looking for a cheap alternative to buying a new crossover.

Its probably a lot easier for you to just solder together a LPF/HPF pair then to program this into a DAP.

[tehmalakai]

Haha yes of course there are many easier options, I was just looking for a free one (minus the time it would take for someone such as myself to code the stuff).  I suppose if I was really desperate I could use two Irivers running rockbox, and use the parametric eq to filter the sound, one Iriver for the LP and one for the HP 

I have soldered together passive crossovers from scratch, but making an active one is quite a bit more complex, especially if you want an adjustable crossover frequency.

Anyways, thanks for the quick reply

[saratoga]

I have soldered together passive crossovers from scratch, but making an active one is quite a bit more complex, especially if you want an adjustable crossover frequency.

I don't see why you would want an active crossover, but making it adjustable and active is only marginally harder then passive and fixed.  You need like 3 extra components.

[tehmalakai]

It needs to be active because I need each signal in standard line voltage to be sent to the amplifiers (separate amps for the lows and highs).  When building an active crossover like that you need to use op amps to boost the voltage of each signal back up again, and a regulated power supply circuit to drive them.  Its definitely possibly but beyond my scope of time and money atm.

[saratoga]

It needs to be active because I need each signal in standard line voltage to be sent to the amplifiers

I don't think you want any gain here, since this would essentially apply an EQ to your signal, boosting the low frequencies much more then the high. 

When building an active crossover like that you need to use op amps to boost the voltage of each signal back up again, and a regulated power supply circuit to drive them.  Its definitely possibly but beyond my scope of time and money atm.

You don't need a regulated supply here since you're not putting any load on it, and theres no way something like this needs to cost more then $10-20, even if you insist on going active.  OpAmps and pots are cheap, and if you really don't have access to DC power somewhere else in your system, a DC supply or even a battery isn't that expensive.