Hi Marc
I've certainly thought about doing that, but not initially since it means that
(a) you would be limited to passive speakers
(b) the specs aren't as good as the Analog Devices ADAU1966, the evaluation board for which is
sitting next to me :-)
(c) serious levels of hardware design needed for the power amps stages
on the other hand, the TAS5508C has a "Full 8×8 Input Crossbar Mixer. Each Signal-Processing Channel
Input Can Be Any Ratio of the Eight Input Channels." and "Mixer gain operations are implemented by
multiplying a 48-bit, signed data value by a 28-bit, signed gain coefficient" so.... 8 speaker
digital decoder, anyone? Only problem is, no way to implement shelf filtering :-(
Dave
On 10/07/2012 02:20, Marc Lavallée wrote:
Dave,
It's possible to skip the A/D conversion by using amplifiers with
digital inputs. Texas Instruments have a 8 channels digital to PWM
converter that can drive D-class amps with PWM inputs; that means only
one A/D conversion, done by the speaker...
http://www.ti.com/product/TAS5508C
Marc
Wed, 25 Apr 2012 15:51:02 +0100,
Dave Malham <dave.mal...@york.ac.uk> a écrit :
Hi Marc,
True, I'm sure you could use a usb interface, but even a low
cost multichannel unit would be quite a lot more expensive (and,
probably, power hungry) than the PI whereas Analog Devices (for
instance) do a 16 channel, 24 bit, 192kHz DASC IC for around 10 ukp
(ADAU1966) which would probably need around another 20 quid's worth
of op-amps and other bits to get going properly. Much more in the
maker tradition - and a possible product.
Dave
PS total number of pre-orders for PI's have reach 350,000!
PPS I'm not connected with them at all, I've not even ordered one!
On 24/04/2012 18:33, Marc Lavallée wrote:
The snd_bcm2835 driver is for the integrated stereo sound module.
For more channels, a cheap 8 channels USB sound module would
probably work, and ALSA drivers for many sound modules are stable.
Martin Leese<martin.le...@stanfordalumni.org> a écrit :
Dave Malham<dave.mal...@york.ac.uk> wrote:
The Raspberry PI is really cheap and runs Linux, so it does
provide some real possibilities, though
it is, in some ways, quite limited - max 256m ram at present, for
instance -
...
it seems that the SPI pins are available on a standard header so
shouldn't be too difficult
physically to add DAC's or ADC's (since most use that interface),
though how easy it would be to
write the drivers, I don't know.
The Arch Linux ARM image (operating system)
contains an ALSA driver. However, it states:
"The alpha-quality ALSA driver included in this
release is disabled by default. Type
modprobe snd_bcm2835
to enable it."
Regards,
Martin
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