Topic: speakers reversed?
Not a big deal, but if you're looking at the Chumby from the front, the output from the left and right speakers are reversed. This is on the production chumby I just received 2 days ago.
~Rolan
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chumbysphere forum → Chumby, the Device → speakers reversed?
Not a big deal, but if you're looking at the Chumby from the front, the output from the left and right speakers are reversed. This is on the production chumby I just received 2 days ago.
~Rolan
I just noticed the same thing playing around with all the cool new audio features in the beta control panel.
I'd definitely put this in the bug category. It's weird when adjusting the balance slider to hear the sound coming out of the opposite speaker you expect. And I doubt anyone's listening to their Chumby with the back facing them.
Chumbians, is this something that can be fixed in software/firmware?
"Me Too"
I noticed the same thing today on my three week old production chumby when playing with the balance control.
There was some debate about how left and right stereo channels should be mapped with the back-facing speakers. The left-right channel mapping should be correct for the headphones. However, many do think this is a bug, so by popular demand, the left and right channels on the speakers will eventually get swapped over to the behavior where they make sense when looking at it from the front.
The problem can be fixed in software by simply changing the channel mapping. However, you would need to link this in to the headphone presence detection code so that when the headphones are plugged in the channels reverse so that it's correct there. Since the plan is to swap the lines in hardware eventually, no fix is scheduled to change this in software currently. The current assumption is that the stereo separation on the chumby speakers is so small, and they are used primarily in the ambient/reflecting sound orientation (so the sound waves get mixed up as they bounce off the nearest wall), therefore L/R mapping is pretty much a moot point on the device, but much more important on the headphones. The argument for the L/R channel to look correct from the back instead of the front is that the only time when the ear can really pick out the narrow stereo separation is when it is in direct line of sight with the speakers, as opposed to bouncing off the nearest wall, which would imply that in this case the user's eyes are facing the speakers. You are not the first users to note that this is counter-intuitive, hence the resolution to change this in the future.
Sorry for the inconvenience!
There was some debate about how left and right stereo channels should be mapped with the back-facing speakers. The left-right channel mapping should be correct for the headphones. However, many do think this is a bug, so by popular demand, the left and right channels on the speakers will eventually get swapped over to the behavior where they make sense when looking at it from the front.
The problem can be fixed in software by simply changing the channel mapping. However, you would need to link this in to the headphone presence detection code so that when the headphones are plugged in the channels reverse so that it's correct there. Since the plan is to swap the lines in hardware eventually, no fix is scheduled to change this in software currently. The current assumption is that the stereo separation on the chumby speakers is so small, and they are used primarily in the ambient/reflecting sound orientation (so the sound waves get mixed up as they bounce off the nearest wall), therefore L/R mapping is pretty much a moot point on the device, but much more important on the headphones. The argument for the L/R channel to look correct from the back instead of the front is that the only time when the ear can really pick out the narrow stereo separation is when it is in direct line of sight with the speakers, as opposed to bouncing off the nearest wall, which would imply that in this case the user's eyes are facing the speakers. You are not the first users to note that this is counter-intuitive, hence the resolution to change this in the future.
Sorry for the inconvenience!
Thanks for the detailed reply, Bunnie. It's really cool to get the inside perspective on how design decisions like these are considered in the development process!
So am I'm understanding correctly that the eventual solution will be a hardware swap of the two speakers? And if this is the case, would a simple system-level patch be a possible fix for insiders? If so, I'd love to see this eventually. Perhaps one of us might be able to write it if Chumby coders are too busy with other priorities.
As it stands, I hate saying this but we are slammed with trying to get our launch release out, so bugs like this won't get fixed until a while from now if ever.
However, I do think that you *might* be able to fix this with something as simple as a patch in the ALSA configuration files, and if not, you should be able to do this by just modifying the TSC2100 driver. The driver is pathed at drivers/mfd/chumby-tsc2100.c; headphone detection code can be found in drivers/char/chumby_sense1.c. I imagine you could modify the TSC2100 driver to poll the headphone detection code and simply swap the polarity of the TFSI bit (bit 2 of the STCR register) to get the channel sense to swap based upon the presence of the headphone. You should be able to test this using only the USB dongle mount hacks using rmmod and insmod. If someone does get this to work, please send us a patch and I'll commit it to our engineering build for further internal QA and ultimately official release.
Of course, things get dicey when we swap the connection in the hardware, because then you have to incorporate version detection code as well. Yuck!
Ah... if those speaker wires were only 2cm longer, the assembly workers could simply plug them in to the alternate connectors.
Hmmm I have a soldering iron. How hard could it be?
As for the software fix, perhaps restate it to 'allow user to configure left-right sound output on control panel' so they can implement it someday without breaking newer hardware.
Hmmm I have a soldering iron. How hard could it be?
As for the software fix, perhaps restate it to 'allow user to configure left-right sound output on control panel' so they can implement it someday without breaking newer hardware.
Hey.. I'm as much a control freak as the next guy, but really I don't think we need clutter the CP with this option.
The Chumbians reasoning is sound IMHO and I agree that it doesn't make a difference. That being said, if you wanna open 'er up and solder away, be my guest!
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