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Board 3 Way DSP Amp

could one use one external ESP32, running Squeezelite-ESP32, and connect the I2S output pins to two of your amp boards? I've never tried to connect one GPIO to two separate input pins.
Yes, it is possible and it will work if we combine the grounds of both boards very well and they are located in close proximity in one case.

Seems like this would eliminate the latency issues when syncing two WROVER chips using LMS???
The thing is that when implementing active three-way speakers, it is optimal to place the boards as close to the speakers as possible. Therefore, when placing the board on (or in) the speaker case, we will have to pull very long conductors to transmit the I2S stream from the I2S source, which requires a good shielded cable, which may still not help and catch EMI. Therefore, to transmit a signal from one speaker to another speaker, an optical channel is used, which is immune to electromagnetic interference. See post number 7.
Synchronization of channels with a DSP on the board is not a problem at all, the DSP delay is constant and easily eliminated.
I know that some people are wary of the optical channel, believing that it has a lot of jitter, but the ADAU1452 has a very good ASRC that successfully restores the signal frequency, and I do not see a single manifestation of jitter in my measurements. I have the same measured values at the DAC output with both the I2S input and the optical input.
I could also configure the ESP32's digital output as S/PDIF and do the same thing???
Yes, it is possible if the boards are in the same case and have one power source and good common contact with the case. If the boards are in different places, then you need to use optics from the ESP32 to the boards, or use an isolation transformer to transmit SPDIF to the boards, but if you use a direct signal from the ESP32 to the boards without galvanic isolation over long distances, then there will be problems with EMI and cross currents between the boards and their power supplies, up to a breakdown of the SPDIF input in the ADAU1452.
So in each specific case, different options for solving a particular problem are possible, if the boards are in the same case and have a common power source with the ESP32, then yes, you can supply one I2S stream to the input of the boards and they will work stably. If they are spread out in different directions and powered from different power sources, then it is highly desirable to use galvanic isolation to supply a signal to two boards installed in different places.
 
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Does I support FIR filters? If so how large?
Yes, ADAU1452 supports FIR filters both in tabular form and in the library form of sigmastudio. The maximum length of the FIR filter is 10,000 taps.

In this topic, in the first post, there is a folder with files for sigma studio, there is a project called - I2S 3Way FIR 48kHz, there is a library FIR filter used to organize a phase-linear crossover, each filter is 512 taps.

https://www.diyaudio.com/community/threads/3-way-dsp-amp.415065/#post-7734899

By the way, Sigma Studio allows you to simulate filter settings without connecting to ADAU1452. So you can open a project and press two buttons of the stimulus and probe and see the result of the filters.
Screenshot_4.png
 
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There are six 3-Way DSP Amp boards available.

PDAC 26.10.2024.jpg


There are six ESP32 I/O boards available.

Input ESP32 24.10.2024.jpg


Six I/O boards without ESP32 are available.

Input 24.10.2024.jpg


The PDAC and input board look like this.

PDAC+Input ESP32.jpg


Price.

One 3-Way DSP Amp board - $95.

One input board with ESP32 - $15.

One input board without ESP32 - $10.

Order more than one 3-Way DSP Amp board and get $5 off.

Payment via Payoneer electronic payment system.

Delivery to Europe and America is at my expense. Delivery to islands or other distant places is negotiated separately.

Those who want to buy the boards, write me a private message.

If you don't want to take risks, I can list the boards on eBay, but it will be 20% more expensive.

https://www.diyaudio.com/community/threads/3-way-dsp-amp.415065/#post-7734938
You can find out a little more about the boards in the thread mentioned above.
 
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Hi @uriy-ch will these be back on sale in anytime soon?
There may well be two assembled boards available next week. Once those are sold, I plan to assemble another batch, but that will be within a month or two.

Also are you able to offer alternative IO boards?
I do not plan on alternative I/O boards.

I also do not plan on using analog inputs, as I believe that using an ADC with an I2S output will result in a decrease in SNR and possible problems with ground loops, background noise and EMI. There are a lot of possible headaches with an analog input.

An optical input is the simplest and most reliable method to get full galvanic isolation between the source and receiver.

People who want to have an analog input simply use specialized network players that have an analog input and an optical output. For example, WiiM.


AES/EBU vertical IO
Such input/output is possible, but only upon request. The implementation time is up to two months.
I have a proven working circuit for ensuring the operation of AES/EBU inputs and outputs, but I do not see a large demand for such inputs, I do not understand in what form these inputs are needed by those who may be looking for them. As I understand it, such inputs are used in professional equipment and usually the required amplifier power is more than 100 W.
Right now I have boards with a spdif RCA input and if an AES/EBU input is needed, then you can use an AES to RCA adapter

coax1.jpgcoax2.jpg
 
There may well be two assembled boards available next week. Once those are sold, I plan to assemble another batch, but that will be within a month or two.
Good to know...

I also do not plan on using analog inputs, as I believe that using an ADC with an I2S output will result in a decrease in SNR and possible problems with ground loops, background noise and EMI.
OK, not so good to know...

I do not understand in what form these inputs are needed by those who may be looking for them. As I understand it, such inputs are used in professional equipment and usually the required amplifier power is more than 100 W.

Home/Small Studios, basically Near-Field monitoring don't require high powered amplification, plus in these applications there is often an external soundcard used to supply the audio, with a large number not having digital outputs.
 
Home/Small Studios, basically Near-Field monitoring don't require high powered amplification, plus in these applications there is often an external soundcard used to supply the audio, with a large number not having digital outputs.
If the external sound card does not have an optical output, then why is it difficult to add an optical output to the computer itself?
USB to SPDIF.pngUSB to SPDIF PC.png
 
I take it this would require a daisy chain between the 2 speakers?
If we are talking about a stereo three-band speaker system, then the input-output board provides the transit of the SPDIF signal. Therefore, one optical SPDIF output is needed from the computer.

Here is a structural diagram of such a solution.
Screenshot_1.png
If you want two independent stereo speakers with an optical input, then you need an optical splitter, which is not expensive. And requires minor modernization to switch the input to the desired output.
Screenshot_1.png
 
By the way, near-field speakers are made on these boards, I know cases when people assembled near-field speakers for recording studios. They were satisfied with the resolution of their speakers. But here it should be said that the final result strongly depends on the correctness of the speaker system itself, and its settings for the studio conditions. Speaker settings are very important, without speaker settings there is no point in expecting a good result. The boards only make it possible to achieve high performance in the speaker system, but do not guarantee this if the speaker system is not optimally configured.
I also have such a solution for active speakers, for those who do not want to assemble everything themselves.
https://www.diyaudio.com/community/...for-3-way-active-speaker.421239/#post-7872817
 
If the external sound card does not have an optical output, then why is it difficult to add an optical output to the computer itself?
View attachment 1414513View attachment 1414514
Works out I'd recently bought something similar to the Reiyin for a different solution, the SMSL PO100.

It was just a pair of Stereo Speakers to be connected, so a daisy-chain from 1 Speaker to the next as expected. I was looking at a 3-Way Speaker build and some of the available DSP Amps available don't seem to meet what I believe are my criteria.
 
There are two boards available.


Price.

One 3-Way DSP Amp board - $95.

One input board with ESP32 - $15.

One input board without ESP32 - $10.

Order more than one 3-Way DSP Amp board and get $5 off.

Payment via Payoneer electronic payment system.

Delivery to Europe and America is at my expense. Delivery to islands or other distant places is negotiated separately.

There is also an input/output board with I2S pins for connecting an external I2S source. Price: $10.

IO I2S.jpg