View source for Talk:Neo Freerunner audio subsystem
From Openmoko
You do not have permission to edit this page, for the following reasons:
You can view and copy the source of this page:
Return to Talk:Neo Freerunner audio subsystem.
You do not have permission to edit this page, for the following reasons:
You can view and copy the source of this page:
Return to Talk:Neo Freerunner audio subsystem.
User:RuiSeabra said:
...
That's very interesting, but - as elaborated to Rui in IRC - doesn't mean much as buzz isn't related to using PGA. Rather using PGA "detunes" the overall setup of mic path, by introducing several new parameters (PGA controls in digital domain of mixer), which Rui hasn't looked at, taken into account, or even finally listed all the relevant settings' values here. Furthermore there's nothing (except AGC, which is considered contraproductive for calypso's NR&AEC, and very unlikely Rui had a working setup for AGC by mere incident) you could implement by using a routing via PGA, rather than just adjusting #5 (#48, #12. In that precedence) to compensate for pathgain changes done by PGA.
Finally buzz is basically completely unrelated to PGA (if not any mixer volume settings) at all
2009-12-01 jOERG--Openmoko HW development and synergy
This is not buzz related (my phone has the buzz fix).
With no electricity or sound engineering background, I can't explain this other than in these terms:
There may be better solutions, but while they are not found, can we at least provide a working sound setting?
The loud static is the result of an overloaded amp stage somewhere in the chain. Routing through the PGA will reduce the signal slightly, reducing the distortion or removing it. The problem is probably occurring in the mono mixer as the default setting (7) has +6dB gain. Reducing it to 5 should help as it will then have no gain.
Wouldn't it be better to insert previous settings into the table, instead of just saying "it's better now"? --Fabian Schölzel 16:55, 17 March 2010 (UTC)