Rockbox Technical Forums

Rockbox Development => Feature Ideas => Topic started by: djrichwoods on September 05, 2008, 04:37:42 PM

Title: Options for Line Out
Post by: djrichwoods on September 05, 2008, 04:37:42 PM
I'm using an Iriver H320.

I've noticed that not only does the Line Out signal respond to the volume control, it also responds to the EQ and Bass/Treble controls.

Would it be possible to make the Line Out jack a true line level output jack that isn't affected by the volume controls, EQ or Bass/Treble controls?  My problem is that I tweak the sound to make my Etynomic ER-6i earphones sound amazing but when I want to play my player over my stereo I have to disable the EQ and pull down the bass level (the bass control provides a much warmer bass response than the EQ control for some reason so that's what I use) as my system doesn't need that.

If the Line Out jack were independent of those controls (or at least given an option to make them independent in the menus) then that would make the transfer between earphones and home sound system seamless.

I know that not all targets have a Line Out so perhaps a menu option isn't an option but it seems redundant to have the Line Out jack act like a 2nd headphone jack.

Title: Re: Options for Line Out
Post by: Llorean on September 05, 2008, 04:42:25 PM
If a line out can be as you described (independent of volume and hardware tone controls) it is. The EQ is a software tone control anyway.

But just save a .cfg file for "Headphones" and one for "Stereo" and swap between the two. It shouldn't take you long. Your request, though, is impossible for this player and pretty much already true on the players where it's possible.
Title: Re: Options for Line Out
Post by: Multiplex on September 06, 2008, 05:44:01 AM
For once I'm not sure that Llorean was his usual crystal clear self...

The this is partly a limitation of the iRiver H300 series (and the H100 analogue output) Hardware. The chip that drives the Headphone and Line out applies the volume setting and tone control to the line out as well as the headphone output.

On some other players (no, sorry I don't know which) the Line Out is extracted after the D to A and before the tone and volume controls. Not all players have the hardware tone controls.

The way Rockbox is currently architected the Equealiser is always applied - even to the digital optical output on the H100 (and I think there is another player with a digital output).

That's a lot more detail but it may not be any clearer.
Title: Re: Options for Line Out
Post by: oayz on September 06, 2008, 05:30:59 PM
Just want to use this opportunity and pitch my idea again:

have 2 automatically selected CFGs: one for battery operation, another for external charger
Title: Re: Options for Line Out
Post by: Llorean on September 07, 2008, 12:48:04 AM
That is kinda unrelated to this task. Assuming power connected is the same as a desire to use line out is a bad assumption.
Title: Re: Options for Line Out
Post by: oayz on September 07, 2008, 05:32:00 PM
Well, it's not 100% but call it "bad assumption" is an overstatement. Let's say when running on battery we are *most probably* using headphones, running from external power - line out (car, docking station, playing through real audio jig, etc.). Since having 2nd CFG is optional and implemenation seems to be stright forward I see little harm in this proposal unless we have more reliable and universal way to detect line out is active.

Ok, my pitch is over :-)
Title: Re: Options for Line Out
Post by: Llorean on September 07, 2008, 05:51:06 PM
Considering a good portion of the players don't have a line out, and the majority of the players with a line out have it inaccessible unless you buy dock hardware, I'd suggest it's much more likely external power is probably not correlated at all to use of speakers.

If charging correlated as strongly to speaker use as you seem to think, we'd have far less people asking about how to charge without mounting, because they could just use the PC to play the music if they wanted speakers rather than to continue listening through their headphones with a minimum of effort.

I'm not saying it doesn't correlate at all, I'm just saying it's a bad assumption to make. What you've offered is not a solution to this problem. It's a solution to another problem, that if it were implemented, would provide a *workaround* to this problem. There are already other things the user could do to work around this problem, so please limit your suggestions to things that actually specifically address this problem, rather than just trying to pitch other ideas that would "somewhat work, but really has a different goal altogether."

We really don't need many threads here being regularly posted in by people saying "What about my idea, which is *somewhat* like this one, but only in special cases!"
Title: Re: Options for Line Out
Post by: oayz on September 08, 2008, 06:24:08 PM
OK, thanks for guidance