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  1. Those GPIO pins can be used for other purposes as...

    Those GPIO pins can be used for other purposes as well, it depends on the software (configration). The TI solution is like the AD's miniDSP. Problem is getting the (right) PurePath software:...
  2. Seems this is late but the PCM5242 chips has a...

    Seems this is late but the PCM5242 chips has a built-in DSP, and you could use the GPIO pins as extra I2S data lines to another DAC (sharing the clock lines). That way you could build for an example...
  3. deleted as duplicate

    deleted as duplicate
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    Seems you probably have to implement a whole new...

    Seems you probably have to implement a whole new USB UAC2 stack. There aren't many open source implementations available, you can find the XMOS and this SDR-Widget for Atmel processors:...
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    The shared gain is a great idea. Us the other...

    The shared gain is a great idea. Us the other half of 1k dual pot with the op amp by connecting it from the negative input to ground via another 47 ohms resistor and a largish capacitor (470 uF at...
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    Nope. We are not handling power here but just...

    Nope. We are not handling power here but just bare voltages, thus the unit is dBu which is exactly 0.775V, and that's what the "Table 1. Maximum output level of microphone (dBu)" referenced earlier...
  7. Seriously? The function used in the filter is...

    Seriously? The function used in the filter is actually "double tanh (double x)" in C(++, whatever), double means 64-bit floating point, both the parameter and return value are doubles.
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    The table gives you the maximum output level...

    The table gives you the maximum output level which for said 20 mv/Pa sensitive microphone will be +4 dBu @130 dB.

    Please use the dB level to voltage conversion calculator here:
    ...
  9. There are some tanh approximations you could try,...

    There are some tanh approximations you could try, see for an example this thread on stackexchange:
    https://math.stackexchange.com/questions/107292/rapid-approximation-of-tanhx
    or this on kvr vst:...
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    Capacitor and even dynamic mics can put out...

    Capacitor and even dynamic mics can put out easily over 1V p-p, even more in front of lets say 100W guitar amp or drum set. With the gain of 50 that means 50V p-p output level. Output level depends...
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    The mic pre (1512) should really have a gain...

    The mic pre (1512) should really have a gain control (linear or rev log 10k potentiometer in series with a large capacitor > 1000uF). Even then there can be too much gain when recording loud sources...
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    Can't say anything about the ths472 chip, doesn't...

    Can't say anything about the ths472 chip, doesn't look professional audio level one to me. Something like That1512 would be much better choice: ...
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    Does the code in...

    Does the code in https://forum.pjrc.com/threads/60532-Teensy-4-1-Beta-Test?p=237578&viewfull=1#post237578 work with Teensy 4.0 and audio shield with ESP-PSRAM64H soldered in?

    Nice to have...
  14. We don't know why there are these requirements....

    We don't know why there are these requirements. Anyway a trivial sampled (not actually sampled but calculated in this case but considered as sample) square wave contains frequency components above...
  15. Problem with the square wave generated that way...

    Problem with the square wave generated that way is that it will be aliased unless the AudioSynthWaveform can produce alias-free waveforms. Using a comparator on aliased trivial square wave would...
  16. Create two sine waves (to left and right...

    Create two sine waves (to left and right channels) with the phase angle you want and then use a comparator to convert the other channel to square wave.
  17. Good to see the problem was solved! You better...

    Good to see the problem was solved!

    You better fork https://github.com/PaulStoffregen/SoundfontDecoder to make the fix, commit it and push it to your github fork and then send Paul the pull...
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    KiCAD seems to have very tight schematic/layout...

    KiCAD seems to have very tight schematic/layout integration, and you can only go in that direction - change schematic in schematic editor ("Eeschema") and import changes into layout (in "Pcbnew"). If...
  19. Please be more specific, which code are you...

    Please be more specific, which code are you running? Have you tried running the other Teensy audio library demos, do they have this same problem. Soundfonts also have loops which are kind of single...
  20. It might be that also the headphone amplifier is...

    It might be that also the headphone amplifier is another possible source of noise, see

    https://forum.pjrc.com/threads/27215-24-bit-audio-boards?p=78831&viewfull=1#post78831

    Sometimes on some...
  21. I think there was an issue with HP of SGTL5000 HP...

    I think there was an issue with HP of SGTL5000 HP filter, if you disable it you'll get much less noise.


    http://openaudio.blogspot.com/2017/03/teensy-audio-board-self-noise.html
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    Thanks for tips, I'll check those china...

    Thanks for tips, I'll check those china companies.

    I might still move the codec to I2S2 as it would free up the main I2S for multi-channel use. Unfortunately every connection (I2S lines) from the...
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    Played little bit in Kicad using whollender...

    Played little bit in Kicad using whollender CS4272 design files. This PCB is too complicated, it could as well be double layer and without those RF isolators (those are fancy though, I didn't even...
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    I think the problem is in the synchronization of...

    I think the problem is in the synchronization of the startup. Basically you should first stop all clocks including that of codec's. Next reset the FIFO's, setup the I2S on the host side with DMA and...
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    Regarding ADC, there is at least the Cirrus...

    Regarding ADC, there is at least the Cirrus (Wolfson) WM8782 ADC which is quite inexpensive and easy to use chip: https://www.cirrus.com/products/wm8782/
    With 0.65mm pitch in 20 pin SSOP is it easy...
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    PT8215 cheap I2S D/A

    (This is continuum to the closed thread:
    https://forum.pjrc.com/threads/59113-PT8215-cheap-I2S-A-D)

    This is good find anyway. PT8211 nor PT8215 are I2S DAC's but relative, they use TDA1545 kind...
  27. BLCK is still connected to wrong pin D22 it...

    BLCK is still connected to wrong pin D22 it should go to D21.
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    Do rather something like this: typedef enum...

    Do rather something like this:


    typedef enum {
    INT16, INT32, FLOAT
    } data_type;

    typedef struct audio_block_struct {
    uint8_t ref_count;
    uint8_t reserved1:6;
  29. I guess you could also use RX_DATA1 pin to input...

    I guess you could also use RX_DATA1 pin to input data using only single I2S interface, but then you had to enable the input pin and increase the frame size, and the audio library doesn't know...
  30. AudioInputI2S i2s1; AudioInputI2S ...

    AudioInputI2S i2s1;
    AudioInputI2S i2s2;


    Is that ok? Shouldn't that be



    AudioInputI2S i2s1;
    AudioInputI2S2 i2s2;
  31. What if you just required that the board is...

    What if you just required that the board is powered only using USB, a phone charger for an instance when it's not connected to PC, or connect the +5V socket to VUSB pins (on teensy) directly, they...
  32. When I'm looking at the schematics and compare to...

    When I'm looking at the schematics and compare to T4 pins I wonder if there is an error. It looks like that the MCLK pin is connected to correct T4 pin (D23) but the pins SCLK (BLCK), LRCLK, SDA and...
  33. Eurorack PSU supplies are +/- 12V so that must be...

    Eurorack PSU supplies are +/- 12V so that must be the absolute maximum range.
    Anyway, for CV's some digital interface could make sense more than the analog, how about ADAT I/O?. ES-8 for an example...
  34. There is a nice 8x8 analog I/O board for FreeDSP,...

    There is a nice 8x8 analog I/O board for FreeDSP, the pcb is available from Tindie except that it's not in store right now (the seller is busy doing another FreeDSP project):
    ...
  35. Configuring via pins practically means that you...

    Configuring via pins practically means that you don't wire the I2C or SPI at all and practically hardwire the used PCM mode (I2S, TDM etc.), sample rates, bit depth etc.. Thus no need for codec...
  36. On iMX RT1060 it is possible to use AD_B1_07 pin...

    On iMX RT1060 it is possible to use AD_B1_07 pin as SPDIF_EXT_CLK (currently mapped to digital pin 16/AD2) as input (via a mux, that's referred as tx_clk2 in RM) for the MCLK3 source in SA1-SAI3....
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    Just some thoughts after browsing github. It...

    Just some thoughts after browsing github.

    It would be a good start for the 16-bit to whatever bit upgrade if the lower level (I2S and TDM, PCM is not supported, meaning MSB left justified,...
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    Are any of these 32-bit floating point forks...

    Are any of these 32-bit floating point forks working on Teensy 4.0? Also there doesn't seem to be F32 implementation for I2S slave mode...
  39. Ok. However, if you use HW configuration mode for...

    Ok. However, if you use HW configuration mode for the converters you don't need any special drivers other than for Teensy (which already exists).

    I hadn't thought the stacking option, that would...
  40. I think you shouldn't try designing one board for...

    I think you shouldn't try designing one board for all possible users and use cases. People who need multiple inputs usually want to record some music performance like drum set with multiple...
  41. Could you actually run Voyetra MIDI Sequencer...

    Could you actually run Voyetra MIDI Sequencer Gold on Teensy 4.0 using this emulator? See http://www.vgmpf.com/Wiki/index.php?title=Sequencer_Plus_Gold

    How about the timing? You should been also...
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    Check out this one: ...

    Check out this one:

    http://www.embeddedartists.com/products/lpcxpresso/lpclink2.php

    Looks like your regular USB JTAG, here for the NXP Cortex-M4 controllers (and implemented using a LPC4370),...
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    There are plenty of DAC's and ADC's but without a...

    There are plenty of DAC's and ADC's but without a proper MCLK output or an external PLL it's not worth using them anyway. Also there are a little bit better codecs like AK4556 which might also be...
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    That's a tiny board, maybe too tiny after all....

    That's a tiny board, maybe too tiny after all. Anyway, for adding memory also consider MRAM of FRAM nv SPI RAM's, might be already fitting the layout.
    Everspin MR20H40 is the MRAM variant with...
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