[Android Head-Units] kaween:
DA-350 preliminary results.

Hi,

This weekend I was able to repair my testbench, so I started on trial runs using the DA-350 DSP sound array. Here's a rundown on the current findings :

1) you do need an attenuator : the line-out output of a DA-350 will oversteer the AN21's soundinput horribly. The attenuator is a simple hackjob, but does work :

DA-350 output (stereo) -------- R1 --------+-----||-------- input AN21

...................................................................................................... | c1

...................................................................................................... |

.................................................................................................... R2

...................................................................................................... |

........................................................................................................|

................................................................... ----------------+-----------------

In this schematic : R1 is 10Kohm, R2 is 100 Ohm, C1 is a 100pf Ceramic cap. The reason for this cap is to filter out a possible DC component coming from the input source.

Failure to place such a cap may destroy your input if you're really unlucky. The DA-350 has a stereo output plug, I simply laid them together and passed them to the AN21 input.

2) using this setup, the DA-350 produces usable output to the AN21.

Results :

1) this setup does NOT produce a "louder mic" level. The attenuation level of this setup is approx 40db. I will make a new setup in the coming days to come where I can change he R1 value to obtain a regulated attenuation between 20 and 40db, and I'll return to this when I have some reproducable and documented results. But with the current attenuator value, the mic volume level of the DA is comparable with a better external mic that is placed near the person using handsfree (mine is placed about 30 cm from my head, it hangs on the roof liner, right beside the front roof light).

2) the array DOES filter out background noise, and it does it in a very impressive manner. My electronics repair corner is in the cellar, and our home's central heating (gasoil, so it produces quite some noise) sits in the same room, about 1,5 meter behind me. When it fires up, it produces a background noise that may be compared to the sound in a seriously loud car. Well, the DA-350 *completly* filters out the background noise. Only my voice can be hears on the BT-call, nothing more, nothing less.

Will I be using this in my car ? Probably not : I'm pretty much satisfied with the sound quality that comes from my existing external mic, and that mic is tiny compared to the seriously big-boxed DA-350 making the DA-350 less easy to place in an elegant manner. I may change my mind depending on later results and possible better ideas to mount the unit in a "visually pleasing" manner.

But yes, if you're having issues with very loud car background noises when using handsfree, the DA-350 is most definitly an impressive piece of hardware. I'm quite sure some modifications on the attenuator will alow for a higher mic output making it even more interesting for people having issues with unusable handsfree sound.

To be continued. :)

[MENTION=5492644]chris.r.r[/MENTION] : looks rad and really looks like it SHOULD have looked like from day one. A bit inspired on Rocketplayer's default layout ? :) I'll flash my spare unit to 2.8.7 this week and see if I can get this to work (same goes for the tuner mod which I never got to work on 2.8.8). Personal I would have likes a somewhat bigger font for the song title. Question : have you gotten this to work with "Music pop up" ? For some reason, Music Pop Up only worked one day on my AN21, after that I refused to show any track info or whatever, independant of used player.

Also regarding that high-pitch noise : it would be the simpler if you'd simply post one of these songs, or dump them on my google drive for example. That way a simple blind test is easy to do. I haven't had this kind of problem with the non-moddd player (just tried the modded player, works nice, oddly enough after that the tuner mod started working too .... but only I had installed the music app. Before that, 2.8.7 gave me exactly the same issues as 2.8.8 when I tried to run the modified tuner app .... very strange).