[Fwd: Re: Docs]

Len Ovens len at ovenwerks.net
Tue Jan 3 04:20:06 UTC 2012

On Mon, January 2, 2012 1:32 pm, David Henningsson wrote:

> Musicians is a very diverse group, and the quality required by different
> musicians is also very different. It's difficult to draw the line here;
> to know what stuff really matters and where it does not.
> A side note: Almost all Codecs have very good specs on paper (like DAC
> S/N > 100 dB, etc), so the quality loss is in general on the analog
> components outside the codecs.

Yup, that was what I was saying.

> For internal mics, an increasing amount of them are being connected
> digitally, like this:
> http://www.wolfsonmicro.com/documents/uploads/misc/en/WAN0263.pdf

That may be the problem I have and why my mic is only 48000. (and has two
channels out of phase) Except it does make me wonder why the same boost is
used for external... but then maybe it isn't, just the controls are the
same. In any case there is still some analogue circuitry from mic to ADC
somewhere even if inside the mic.

> I'm still very interested in knowing your ALSA info (see
> http://wiki.ubuntu.com/Audio/AlsaInfo ), can you please give it to me?

Attached. It says my audio is wonderful. (16/20/24bit,
44100/48000/96000/192000) I would guess that these two lines below say the
mic and external mic pre are separate devices?

[   20.152166] Bluetooth: RFCOMM ver 1.11
[   20.344422] input: HDA Intel Mic as
[   20.351928] input: HDA Intel Headphone as

Maybe that is why the internal mic sounds so bad at 44100. (the external
is ok though)

> (But how many of those would succeed in an A/B listening test?)

On computer speakers? Even on most people's stereo? For that matter even
going through a crown amp to bagend speakers most people would not be able
to tell the difference. In fact most people would pick the loudest ones as
better no matter the quality. Certainly most people can not tell the
difference from 16bit to 24bit or 44100 to 96000hz. Two channels to five
for surround? Most people would notice that. However, multi-track
recording, effects and mixing start to show funny things much faster than
playing an MP3s or game sounds. The people who test audiophile cards, test
them against each other... I don't know what kind of golden ears they have
though many of the comparisons end up being based on manufactures specs.
The Intel blurb on HDA is just that, a blurb. There is not link to actual
specs or users manual for their chips. They do point to the AC97 spec as
background needed to understand the HDA spec... then give a link to their
own site... but the document doesn't exist. It all seems to point to HDA
being a hopped up AC97 with a new interface... with the hopped up part
being optional...

To be fair, I did not buy the netbook for sound, I have a desktop with a
pci mutitrack soundcard for that. It is only as I have been doing test
installs on it that I wondered what I can do with the audio on it. Can I
hear the difference between the Delta66 and the AC97? Yes. no problem,
even using the cheaper/noisier mixer mic preamps in the Yamaha RM602
designed for tracking to 4 track cassette. (My Mackie pre amps are better)

> As I've said before, given your alsa-info I might be able to write a
> driver quirk that turns it into a mono mic at the ALSA level.

It does already, my recording software reports it as a mono signal. It is
the manner in which it does so. Alsa seems to mix the two channels
together. Just use left should work fine.

> https://wiki.ubuntu.com/UbuntuStudio
> That said, I don't know what quality that documentation has.

It is the reason for my lame attempts. It seems to list the software that
came with US a number of releases ago. The most up to date part is still
one release ago... the link that points to daily development ISOs says
Oneric. Some of the IRC logs for the meetings is current though. US
webpage is one of the big projects this cycle. I'm new, mostly doing
testing of ISOs, trying to do some docs cause no one else is.

>> that all Xubuntu's documentation is copyright the ubuntu documentation
>> project. Should I be using the same copyright/license (artistic)? Is
>> there
>> a template I should be using? Point me at a web page if that is the best
>> way for you to answer this.
> I don't know, but if I were you, I would start looking at
> https://wiki.ubuntu.com/DocumentationTeam

Thank you.

> I'm not sure how our different types of documentation are organised, and
> what types of documentation can go into where based on which criterias,
> maybe Scott might know more of how that stuff works?

Ah, no. I think just about everyone now a part of US is pretty much in the
dark on docs, we all can see we need them. I think Scott has enough to do
right now.

> I recently made the general audio troubleshooting sections at
> https://wiki.ubuntu.com/DebuggingSoundProblems and
> https://wiki.ubuntu.com/Audio up-to-date.

I'll use them.

> Sorry if I sounded harsh. It's just that it's not the first time I see
> documentation that is based on individual pieces of hardware and the
> documentation writer making the assumption that everyone else's hardware
> works the same way. I understand that it is difficult to get the
> overview - to know what problems are common and thus worth mentioning in
> a general "help" page, and which ones are not.

I will see what I can do. Going will be slower now though as I go back to
work soon... Your comments will help us have better docs, in the end that
is what I want. I will keep trying to find some real HDA documentation. I
will list most of what I have as being AC97 info as that is where I got
it. I don't have the resources to try out different hardware and see how
it works.

Len Ovens
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