I've used one of the miniDSP kits (actually three USB Streamers) in a design project, and it did perform well, but we never did any of the actual DSP onboard and instead relied on computer software. Also, they tend to keep their onboard firmware locked down pretty tight at least for the model we used.
Your options mostly go like this and people are free to disagree
Not Recommended for what you described:
- Dedicated DSPs (DSP Microcontrollers): medium-high cost, highest integrated ADC/DAC quality, usually highest
performance, medium development difficulty, low portability
- FPGA Board: wide range of cost but mostly medium-low for audio, peripheral ADC/DAC quality varies, medium-high performance is characterized as low-medium clock speed but very high parallelization (there is no defined ALU), relatively high portability when done hierarchially, high development difficulty,
- Standard Microcontroller: low cost (dirt cheap depending on implementation), wide range of specs and features, generally faster clock speed than an FPGA (but you sacrifice parallelization) which gives it pretty high audip performance, decent ADC/DAC but not audiophile grade, medium-low portability, low development difficulty
- Consumer Platform Software: At the end of the day, your algorithms start here. You should have MATLAB, GNU Octave, Python (Anaconda or WinPy), or something similar to do the testing on, or your life is going to be difficult. I'd say only move on from here once you are comfortable creating the entire DSP portion of the solution in these environments.
Honestly, these days audio performance is cheap on the digital side. The expensive part is having good converters. You shouldn't have to touch the top 2 solutions until you are getting into some crazy stuff. Start off with the PC software and slowly apply the concepts into a microcontroller project using C and RISC assembly.
For books I highly recommend Discrete-Time Signal Processing (Oppenheim, Schafer). If you need something a bit less reference-book-like, DSP First (McClellan, Schafer) provides a shorter and sweeter background. Honestly the online resources from MathWorks, Wikipedia, and here should fill in most gaps.
There are some good acoustics/audio engineering books out there but none of the ones I've read really go into the digital aspect of it all. They mostly speak about the nature of sound waves and propagation from an electrical and mechanical standpoint. Acoustics and Noise Control (Barron) is a good one, just ignore the proofs (partial differential equations are unholy).