On Mon, 28 Sep 2020, Alan Corey wrote:
I would say you're in danger of overthinking it, try the defaults first.
And read the man pages.
Except when you say 24/192 I'm thinking 192 kbits/sec? My usb sound
I presume he means 24 bits per sample, 192K samples per second per channel
which gives 1.2MB/s data flow (2channelsx3bytes/sample/channel x192000 samples/channel/sec)
cards can only do 48 max. Yours may do better. I was just looking
into it for SDR purposes, the tuning range depends on the max sample
rate. SPDIF has always seemed like the way to go, or maybe firewire.
But you need to study the E-MU 0202 specs to be sure it can do 192.
It claims it can.
On 9/28/20, Zsolt Ero <zsolt.ero@xxxxxxxxx> wrote:
Hello,
I have a few questions related to arecord, which I couldn't find in
the man pages nor anywhere on the internet.
My use case is very simple, I'd like to record stereo 24/192 audio
into a WAV file from an E-MU 0202 USB interface using an old laptop
(Core 2 Duo).
For this I thought of using the device which starts with "hw:", as it
seems to me that it provides the least processings over it. The
recording works without problems, however I'm confused about the
options.
What is not clear to me:
--mmap - should I use it or not? I'd be writing from USB to hard drive
a wav file.
--period-time, buffer-time, period-size, buffer-size - I'm totally
confused about these. I'd like the highest possible recording quality,
latency doesn't matter to me.
--avail-min - what is a wakeup?
--disable-resample/channels/format/softvol - do I need this if I
selected the hw: device? I'd like to record without any kind of
processing.
You do not want to resample. Stereo is 2 channels ( the default), you have to
figure out what format the 3 bytes of data are delivered in.
But I agree, why not try the defaults.
Note that 24/192K is way overkill. 24bits is about a 10^9=180dB dynamic range.
This is way way way more than any microphone/amplifier can deliver. They are
more like 100dB at most, from a noise floor of around 30dB to a loudest sound
(with clipping) of about 120dB. Also most of that frequency range of
27 octaves that 192K gives you is wasted since the ear can only at best (for a
10 year old) hear about 20 octaves.
--test-position/coef/nowait - do I need this for my use case?
Thanks and regards,
Zsolt
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