Hi, at this moment we are working with a famoush spanish craftsman to digitalize his hurdy gurdy. We are now on the investigation step, and we are looking for some IC, or a conjunction of IC, that could help to do our task. Because a FPGA DSP based development its not worth at all in time on this proyect. At this moment we have a "rudimentary" analog desing that works but isnt flexible enought to meet the requirements we need.
Instead of use a FPGA we are looking for some IC that could make audio operations (filters, volume control, EQ...) with the input channels. We control and tune every instrument independently, so the filters, EQ will be program on the chip without the operation of the final user.
The instrument in question, have 4 ways to generate sound. Its like to have 4 instruments in the same side.
On the image we can see 6 numbers:
- Melody Strings (Number 1): This generate the main sound of the instrument, this need to be recorded with a high quality microphone.
- Drone Strings (Numer 2 and 3): This cords acomplish the Melody Strings when they are used. They need to be recorded with a pair of electrect microphone
- Resonant Strings (Numer 4 and 5): This cords create a resonant sound, this give to the instrument a deep sound like if you was in a cathedral with the instrument. They need to be recorded with a eletromagnetic disk, like the electric guitar have.
- Ambient sound (Number 6): This is a mircophone that could be use or not, it depends on the artist and the situation.
The outputs of the instrument should be:
- A merge output: An output where all input sources are merged. Normally we are using here a Jack to output the sound.
- An independent output: On this side we are testing some connectors, but here the inputs should go out with the audio operations but without merge. They are used on concerts for example, where we have a mixing desk that equalize all of the intruments playing and the sound of the singers.
All of the outputs should be amplified, but normally with the gain of the Audio or PCM DAC chip should be enought, this could be tested on the first prototype boards, and if needed i will see for some Texas Instrument Solution Amplifier.
Human interface: In this phase, we need to control each input independently. Because the artist must have a absolute control on the inputs to control the output of them. At sometimes you want to be the Melody Strings a few more loud than the Drone Strings for example, but it depends on the situation.
At this moment, on the analog board we have potentiometers on it, but buttons or a mixed solution with an intermediary MCU could be done without problem.
Block diagram.
As the PCM have 2 ouput DAC, maybe we could use 3 instead of 6 units. One with the Melody Strings and Ambient sound (Using R and L channel), other for the Drone Strings (R-L) and other for the Resonant Strings (R-L)
This could be more easy the complete solution, as the total number of PCM in use will be 4, not 7.
Regards, Carlos.
