Cheap DSP to learn about active multi-way speaker

[robca]

I built a couple of DIY speakers (Quark and Speedster), and I really enjoy how much value you can get for not much money.

One day I'd like to build a bigger/better multi-way speaker using something like Hypex Fa123, but I have too much to learn before I start spending real money.

I was thinking of starting with something much cheaper to get into active crossover and active speaker designs, using a ADAU1701 board and cheap chip amplifiers.

I looked at some of the Sure offerings, e.g. WONDOM | STORE or even WONDOM | STORE which will allow to build a 2-way design with just a power supply. Or WONDOM | STORE for both speakers.

But I've read mixed feedback on the Sure modules, so I'm wondering if there are better boards I should consider. Any advice in how to get started is welcome

[benjaminandrews38]

If this is for learning, and you don't mind stringing together a few modules then have a look on aliexpress for ADAU1452 boards. It has significantly more power than the 1701. For about 90 dollars you can get a board that has a 4 in 8 out codec and the device to program it.

[bradleypnw]

For development a Dayton DSP-408 + a used home theater receiver (e.g. Yamaha RX-V667) with separate inputs allows you to make on-the-fly adjustments. After you've worked out a design you can move to individual components.

[xrk971]

I learned how to use DSP with a basic miniDSP 2x4 ($80) and a pair of TPA3116 amps ($10 ea). Plus a microphone ($100). Add REW software and for about $200 you can do 2 way speakers any way you like.

The Dayton DSP-408 is nicely made and software is simple and easy to use. Nothing extra to buy as miniDSP charges for the different modules. It won’t do fancy filters though.

ADAU-1452 and SigmaDSP is super powerful but more complicated. The official EVM from AD is $225. Worth it in my opinion vs an AliExpress unit with zero documentation and questionable parts (ADC and DAC).

[robca]

Thanks for the input so far.

Let me add some more info to my requests. I'm relatively proficient in microprocessor and digital electronics, having built and programmed a variety of boards (mostly ESP32, STM32 and nRF52). I do have a decent oscilloscope (Rigol DS2302A), signal generator, logic analyzer (DSLogic) and multimeters. I also have an UMIK-1 and used REW to check out my kit speakers. I know nothing about DSP but have some understanding of digital protocols (e.g. I2S, SPDIF) used in a modern audio device

At the moment, I'm more interested in learning and figuring things out than listening to high quality sounds. And I'd like to learn more about handling sounds purely in the digital domain (then converting to analog at the proper time). I'm not worried about adding extra modules and having to solve problems

And at the moment I really want to spend the least possible, given that I still "don't know what i don't know", so spending a couple of hundred dollars without knowing what for is less than ideal. A Dayton Audio DSPB K and DSPB KE or similar Sure Electronic is ~$35 shipped, which is much more interesting. Plus the programmer, and I was thinking about using a CY7C68013A board (and all the necessary black magic to make it work)

A generic ADAU1701 (or 1452 as suggested here) should allow me to use a purely digital input (I2S or SDIP-to_I2S converter) and either output an analog signal over 4 channels, or 4 I2S channels (assuming I understand how the ADAU1701 works). Then I can further decide how to handle the output (for example, using the ADAU1701 board as an equalizer and sending SPDIF to a stereo amplifier)

Going with a DSP-408 or similar "ready" devices, assumes purely analog input and output. The same would be with a Dayton Audio DSPB-250

Am I right in thinking that with a DSP board (Dayton Audio, Sure Electronics or similar) and plenty of time, I could build both the equivalent of a speaker crossover or modify I2S signals?

[bradleypnw]

Originally Posted by xrk971

The Dayton DSP-408 is nicely made and software is simple and easy to use. Nothing extra to buy as miniDSP charges for the different modules. It won’t do fancy filters though.

I didn't think of miniDSP. I need to ask them if they have the gradient low-mid frequency cancellation utilized in this paper.

https://aaltodoc.aalto.fi/bitstream/...=2&isAllowed=y

[Piersma]

freeDSP main thread

freeDSP | An Open-Source Low-Budget Audio DSP
freeDSP | An Open-Source Low-Budget Audio DSP

[robca]

Originally Posted by Piersma

freeDSP main thread

freeDSP | An Open-Source Low-Budget Audio DSP
freeDSP | An Open-Source Low-Budget Audio DSP

I'm a bit at a loss here. I did look at the freeDSP site and various boards, but especially for someone living in the USA, the prices are simply not competitive at all. I can get one of those eBay/Aliexpress "green ADAU1701" boards for $18 shipped.

None of the freeDSP boards I found for sale (and that might be poor search skills on my part) are close to the direct-from-China prices and there doesn't seem to be any additional value offered in the freeDSP boards outside of being open hardware, which is nice but not enough for my purposes.

What am I missing?

[xrk971]

Hi Robca,
You actually have lots of good experience then. The ADAU1452 from AliExpress might even work if you are handy either SPI/I2S/I2C and programming MCUs.

The ADAU1452 EVM is also a good choice. It has headers to access the SPI/I2S stream in out out. Has SPDIF too.

[benjaminandrews38]

I'd recommend downloading and playing with sigma studio before settling on a specific dsp chip. you can throw a few filters together quite quickly, and see whether or not your program will fit on a 1701. Furthermore, the more ubiquitous 1452 options on Aliexpress have the dsp chip on a seperate board to the codec, that way if you wanted to roll your own adc/dac board it could give you a jumpstart.