<AutoStatic>
So you've got some commercial interest too with your project?
<FergusL>
maybe for the DIY instruments, but not commercial as I could sell them, not now, just sell my "expertise" with the paper sensors
<AutoStatic>
DIY instruments are quite hot at the moment
<FergusL>
but really it's not much right now, I'm still a student, it's not like I'm having plans, partners etc... "commercial" to me would just mean that I intend to make money from it as a humble maker and decide that *it* is my professional occupation
<FergusL>
let it be so then about their hardware !
<AutoStatic>
hramrach__: Why the Android logo?
<FergusL>
haha
<FergusL>
isn't it written "
<FergusL>
isn't it written *linux* right there ? ffs !
<AutoStatic>
FergusL: They'll probably open source part of it too
<AutoStatic>
of their hardware
<hramrach__>
AutoStatic: make a better one and but tsvetan to put it on hte wiki ;-)
<hramrach__>
*bug
<FergusL>
I doubt they made one for themselves
<FergusL>
(a board)
<AutoStatic>
Ah ok, so it's basically some preliminary logo.
<AutoStatic>
They made the audio interface themselves
<AutoStatic>
But I don't think they made the board no
<FergusL>
yes
<FergusL>
funny I'm also intrested in making usb audio cardss
<hramrach__>
eveyone needs USB audio cards ;-)
<AutoStatic>
I don't think it's USB they're using
<FergusL>
if their board has I2S then it's this
<FergusL>
otherwise, definitely usb I guess
<hramrach__>
do they use a PC board?
<AutoStatic>
MOD is using a x86 board yes
<hramrach__>
and have you seen PC with I2S?
<FergusL>
well maybe not !
<FergusL>
but isn't it common on those computer boards ?
<FergusL>
I'm not mixing up with I2C
<hramrach__>
i'm note really familiar with the internals of x86 hardware. they only provide the user spec for most boards but there are some which have like SPDIF addon which has to be connected somehow
<FergusL>
well actually I don't know
<FergusL>
AutoStatic: about the box, I was even having the idea of making an universal "baseboard"
<Astralix1>
Why should there be an PC with I2S?
<FergusL>
with a usb DAC (==sound card) on it, a USB hub and a microcontroller with a few multiplexers to allow for more inputs
<Astralix1>
I2S is a short range signal used from Codec to DAC
<FergusL>
from cpu to device, then ?
<hramrach__>
which is exactly what you want for custom audio application but most PC boards won't have
<Astralix1>
from Codec to DAC or if available from uC to DAC or SPDIF receiver to DAC
<Astralix1>
a custom audio app should have inputs for usual signals and I2S is local signal only as it is difficult ot transport over longer cables.
<FergusL>
if you look for "diy dac 2706" you'll find some infos
<FergusL>
but I wonder how good it is, how easy it is to make one and ultimatlely how much does it help reagrding latency
<hramrach__>
if you hve I2S you get to pick the DAC and don't have to rely on the board maker to put somehting sane on the board
<Astralix1>
the quality of the audio coming out of a dac is not based on the dac but on most peripheral components and knowledge of PCB layout
<FergusL>
like, capas quality ?
<Astralix1>
and almost all DACs that where high fidelity quality have been taken from the market
<hramrach__>
unless I am missing something the I2S is digital so you can connect your own analog part with as much power conditioning and shielding as you want
<hramrach__>
an you don't like hear the hardrive motor in the audio output
<Astralix1>
So what you need is a separately powered Soundcard.
<hramrach__>
like the USB one
<Astralix1>
and if you're really hifi, then you should use something that is not electrically connected to your computer
<FergusL>
yes
<Astralix1>
So use SPDIF to drive an external box that is then powered by high quality supply
<hramrach__>
you can use SPDIF on some PCs but USB is probably good enough
<FergusL>
but here we're talking about a small box with inside a small computer AND a small sound card
<Astralix1>
So take a STM32F10x and a DAC
<Astralix1>
sorry, you should take a STM32F40x
<Astralix1>
it has I2S and USB and if you like ethernet too
<FergusL>
why the stm32 ?
<Astralix1>
It is well supported, reliable and long living
<FergusL>
hm... I was thinking about an ARM cpu, running linux and with some processing power for the actual audio processing
<Astralix1>
so if you open you schematics, other may build the same thing in 10 years
<Astralix1>
STM32F40x is ARM Cortex M4F
<Astralix1>
It is an Cortex M3 with Floatingpoint and DSP extensions
<FergusL>
yes, I have the discovery board
<FergusL>
but erh... it must be 96MHz or something ?
<FergusL>
AutoStatic: did you check dual-core thread usage when running the audio applications ?
<Astralix1>
It has everything you need
<Astralix1>
Hmm... guys do you want to have a soundcard or a stand alone player or what?
<Astralix1>
For audio USB->DAC STM32 is fast enough looong way
<AutoStatic>
FergusL: no because I used Jack1 and Jack1 has no SMP support
<Astralix1>
Decoding is done in CPU or VPU. The STM has power enough to do some volume, equilizer and may be some display control to show current format and so on.
<AutoStatic>
Astralix1: no stand alone player, I also need audio in
<Astralix1>
And the STM32F4 has 120MHz if you like
<Astralix1>
STM32F4 has I2S input too
<Astralix1>
so an ADC can do that
<AutoStatic>
Such boards are way too low level for me, I'm a Linux guy, not a hardware guy ;)
<Astralix1>
But I had same problems with my PC too... Harddrive noise in Earphones...
<Astralix1>
I am both
<Astralix1>
Rohde & Schwarz Audio Analyzer sitting right behind me :)
<Astralix1>
But I recently bought a Creative X-Fi USB dongle and it works quite well with my Sennheiser headphones
<hramrach__>
yes, USB cards tend to work much better than onboard
<Astralix1>
So if Hardware is too low level for you, then why talking about I2S? It is a signal you never get to see outside a PCB
<hramrach__>
I removed the harddrive and that works good enough too
<AutoStatic>
Astralix1: I didn't mention I2S
<hramrach__>
some PCBs have it on pin header
<Astralix1>
it was hramrach__ i guess
<hramrach__>
it was FergusL I guess ;-)
<Astralix1>
Yes but it is not easy to handle as you have LRCLK, MCKLK, BCLK and DATA
<hramrach__>
you probably want to handle it with a chip designed for that
<Astralix1>
yes, but the pcb must sit directly on that connector
<FergusL>
yes it was me because by reading the specs of easily available DACs I saw I2S mentioned
<FergusL>
along with usb
<Astralix1>
there are a bunch of audio chips
<FergusL>
AutoStatic: uh, even for LV2 effects etc... ?
<AutoStatic>
Those all go trough the JACK graph so yes, even for LV2 effects
<Astralix1>
you can have USB->I2S, USB->Analog, I2S->analog, I2S->PA, USB->SPDIF, SPDIF->I2S....
<AutoStatic>
But then Jack2's SMP support only works for parallel connections
<AutoStatic>
"SMP support is not always as valuable as you would think. If your applications are chained INPUT --> A --> B --> C --> OUTPUT, then it will not be able to utilize multiple processors. However, if you applications are independently generating audio to the OUTPUT, that is when "parallel" sub-graph exist in the global graph, then they can be."
<Astralix1>
but this is irrelevant for the OUTPUT in this case
<Astralix1>
the OUTPUT can be whatever device
<Astralix1>
Not mentioned is the delay introduced by cross-media-conversion. So from audio-output-stack to USB soundcard driver, packaging, sending, USB decoding, packet uplining, sending via I2S, DAC->Analog
<Astralix1>
So using the internal oboard sound SOC on the mainboard and instead of taking the noisy analog out, put a digital on SPDIF, Jack can go fast, no delay and you can use high quality hardware
<Astralix1>
on the other end
<AutoStatic>
Couldn't agree more
<Astralix1>
If you like to do studio, you should use low latency devices or some with multiple options
<Astralix1>
Buy a UD-H01-B Dac or something
<FergusL>
sorry I couldn't follow the whole conversation
<FergusL>
AutoStatic: is it right I "know" you from the PureData forum ?
<AutoStatic>
FergusL: No, I'm not a Pd user
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<FergusL>
hm, okay, must be... Arduino ? Codelab ?
<AutoStatic>
Linux Audio
<FergusL>
ha okay
<FergusL>
I thought it was a more specific forum
<AutoStatic>
I'm an active contributor to the Linux Audio community
<FergusL>
okay
<Astralix1>
good to know
<AutoStatic>
So my nick could pop up here and there
<Astralix1>
So how about a Focusrite Scarlett 2i2 to solve you problems?
<Astralix1>
heard that it should run fine with linux
<Astralix1>
I have a Terratec DMX 6fire USB here, but the driver isn't maintained anymore or the maintainer cannot put it on the kernel list.
<AutoStatic>
Astralix1: I already own the necessary hardware
<AutoStatic>
But I'm planning to buy a new USB interface
<Astralix1>
Ah... and then what's wrong with my suggestion on the Focusrite?
<AutoStatic>
Focusrite is OK, got a Saffire Pro 40, but I'll probably buy a Presonus
<Astralix1>
ah
<AutoStatic>
Nothing wrong with the suggestion, apparently it's a great interface with decent Linux support
<Astralix1>
tell me why, cause I only bought the Creative for a quick solution
<AutoStatic>
You mean the choice for a Presonus?
<Astralix1>
Yes
<AutoStatic>
I want to get rid of my Focusrite Saffire Pro and get a Presonus 1818VSL
<AutoStatic>
FireWire is exit
<AutoStatic>
My new notebook has no means to connect a FireWire device to it so I need a decent USB interface with equal IO
<Astralix1>
I am not doing studio I/O but develop or wressle around with audio hardware some times. So I love to have really good audio signals for reference
<Astralix1>
So I search an interface that has only few I/O.
<AutoStatic>
Then go for RME or something like the Focusrite Forte
<AutoStatic>
RME Babyface
<Astralix1>
Yes I thought
<AutoStatic>
Or if you got the money, Prism Audio Lyra
<Astralix1>
Looks like I had to sell the UPD analyzer for that one...
<Astralix1>
Better to use the UPD as headphone preamp...
<Astralix1>
I guess the babyface is good enough
<AutoStatic>
He he, yeah Prism Sound is quite expensive stuff
<FergusL>
i've an old one, a Tascam FireOne, unfortunately linux support is very limited
<Astralix1>
The Terratec DMX 5fire was very good too, but the linux support is horrible
<Astralix1>
had to recompile the drivers from a private repo everytime y new kernel was coming
<AutoStatic>
I've never used the Terratec devices but I've heard good things about them
<FergusL>
and I think, for "our project" (if AutoStatic allows me to say so) a complete Usb soundcard is not the best option
<Astralix1>
and with kernel 3.8.x the new driver fails and crashes
<AutoStatic>
:(
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<AutoStatic>
3.8 has USB issues
<Astralix1>
The sound is very good
<Astralix1>
but it is now parked and I use cheap Creative dongle.
<AutoStatic>
FergusL: I need input and output so I'll probably need a complete USB interface
<AutoStatic>
But I'll be staying on the veeeerrrryyyy cheap side ;)
<FergusL>
sure yes !
<FergusL>
there are some small usb sound card
<FergusL>
usb powered, very small, but not those uber cheap chinese cards
<FergusL>
even though there is a chance they use smilar chips
<AutoStatic>
Astralix1: bummer :( I mostly use my old and revered Edirol UA-25 at the moment
<AutoStatic>
Those cheap USB interfaces all use C-Media chipsets
<AutoStatic>
That's crap (even though I can achieve very low latencies with them)
<AutoStatic>
Cheapest option with a decent chipset is probably ... http://instantrimshot.com/ ... Behringer
<AutoStatic>
They're using TI chipsets, like the PCM2706 you mentioned
<Astralix1>
I have these chips and lots more
<Astralix1>
but i have actually no time to design a nice board around them
<Astralix1>
There are even 192kHz DACs with mil standard and guaranteed drift and offset in my collection
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<FergusL>
AutoStatic: what model from behringer ?
<AutoStatic>
UCG102
<AutoStatic>
But it has headphone out and you rpobably don't want that
<AutoStatic>
%s/rpobably/probably/g
<FergusL>
it's fine
<FergusL>
depends on the setup
<AutoStatic>
For a stompbox?
<FergusL>
if you're on a stage, the sound guy will probably look at you with a very weird face
<AutoStatic>
Neh, you don't want to know how many guitarists use Line6 pods and all
<AutoStatic>
But this is where I lack the necessary knowledge
<AutoStatic>
Catching up though ;)
<Astralix1>
I just like to have some real high quality audio, 90% on headphones, 10% on a self made Preamp/Amp system
<FergusL>
AutoStatic: also, now that everybody brings his mac or ipad to trigger samples... soundguys have to adapt haha...
<FergusL>
and I think a DI box does the trick
<AutoStatic>
I don't want to use a DI, I want to stick the stompbox in my existing FX chain
<FergusL>
haaaa ! that's different
<FergusL>
didn't think about this actually
<AutoStatic>
My idea is actually a Hammond/Eddystone enclosure with an ARM board, audio in and out, footswitch and maybe one or two knobs
<AutoStatic>
And then work with presets
<FergusL>
it could do so much more !
<FergusL>
yes
<AutoStatic>
Sure it could do more, I could also use it as a synth MIDI module
<AutoStatic>
For instance
<Astralix1>
so, I think I do something this channel was originally meant for... I do some linx kernel dev on the rockchip mainline kernel support