2011/10/20 Charles Henry <czhenry@xxxxxxxxx>: > ... feedback for a project, namely building an > audio interface, with the goal of creating freely available schematics > and code ... > > The concept is to create a modular and scalable system that allows > users to create a sound interface with an arbitrary number of > input/output channels. Great project ! Maybe try some fund-raising ? Now, say thanks to those xmos people, they have a whole reference design ready, inclusive buyable prototype: http://www.xmos.com/products/development-kits/usbaudio2mc Note: This is based on xmos technology, XC - a C like language, that allows implicit parallel programming. I heard USB-Audio-Class-2.0 is already supported by ALSA (driver architecture), thus this device might work OOTB or with very little effort on linux. In the following, some of my ideas: You could take it as base, - modularize it further - or add some missing components, - make IOs balanced, - add ADAT - add AES3, (AES/EBU) - add AES10 (MADI) - add AVB - support MIDI IO - Allow the synchronization of two or more cards, to allow more than 6 IN channels. - Make most of it optional and modular. - Make 1 (extensible) low-cost + 1 (all-incl.) high-end design Since most of the modules exist, work is to connect and integrate all of it, and the design of a beautiful case and package ;) I would make most of the design digital, with the exception of pre-ADC (analog limiter, balancer) and post-DAC (amplifier, balancer) stages. You would end with about these modular stages: - analog inputs ADC_01 ... ADC_XX - ADCs would deliver I2S streams, send to a mixer (fpga ? or xmos uC) , or directly to output modules. - digital IO SPDIF - digital IO ADAT - digital IO AES3 - digital IO AVB - digital IO USB 2.0 - digital IO IEEE 1394 (maybe) - digital word clock (75Ω BNC) - analog outputs DAC_01 .. DAC_XX, would receive digital I2S streams - controler , routing-, configuration- and switching module Digital INs would be routed to the mixer stage. Digital OUTs, could optionally be routed back to the mixer stage, maybe with a feedback-loop detection, to prevent damage of ear and device. -- E.R. _______________________________________________ Linux-audio-user mailing list Linux-audio-user@xxxxxxxxxxxxxxxxxxxx http://lists.linuxaudio.org/listinfo/linux-audio-user
