Forum Rule: Always post complete source code & details to reproduce any issue!

Search:

Type: Posts; User: jonr

Page 1 of 10 1 2 3 4

Search: Search took 0.01 seconds.

  1. While 9216x2 taps is OK, it could go higher if...

    While 9216x2 taps is OK, it could go higher if DMAMEM could be used for some of the large arrays (eg fmask). But with USB input and spdif output, this causes some static. Any idea why or how to...
  2. As I recall, the pedvide ADC library has the...

    As I recall, the pedvide ADC library has the obnoxious side effect of turning on interrupts.
  3. Here is the alpha code if you need two impulse...

    Here is the alpha code if you need two impulse responses applied to two channels:
  4. Replies
    3
    Views
    210

    I think you want: float32_t inbuf; ...

    I think you want:

    float32_t inbuf;

    myFile.read(&inbuf, sizeof(inbuf));
  5. Replies
    5
    Views
    309

    I always get 223.98 when using a double. "%.2f"...

    I always get 223.98 when using a double. "%.2f" works even with a float.
  6. > This seems all pretty unstable. Possibly...

    > This seems all pretty unstable.

    Possibly related - I found the audio+midi+serial option to not work with T4.0 and Linux. Serial alone or audio alone (except for volume control) has been fine.
  7. Replies
    3
    Views
    157

    There is lots of info about time accuracy on this...

    There is lots of info about time accuracy on this forum. Consider doing your own temperature compensation. Or using the RTC.
  8. Replies
    4
    Views
    203

    Another issue/bug: any call to usb1.volume()...

    Another issue/bug: any call to usb1.volume() causes the audio device on linux to stop working.

    * Linux Mint, Arduino 1.8.13, TD 1.53
    * Teensy 4.0 with toslink/spdif3 output
    * USB Audio in
  9. Replies
    19
    Views
    393

    It probably helps (lower jitter?), but experience...

    It probably helps (lower jitter?), but experience says it isn't necessary.
  10. I have code to alpha test if anyone is interested.

    I have code to alpha test if anyone is interested.
  11. Agreed, unless someone with better understanding...

    Agreed, unless someone with better understanding wants to help, creating a second fmask array and then running the existing multiply/ifft process twice better fits my limited understanding of this...
  12. > both IRs (for left and right speaker channels)...

    > both IRs (for left and right speaker channels) are both stuffed into the maskgen buffer

    I thought about this, but if this would work, how does it work as the code is now? The imaginary/odd...
  13. Replies
    19
    Views
    393

    +1 on what Paul said. Since this keeps coming...

    +1 on what Paul said. Since this keeps coming up, here is one that can be copied. Note the guard ring and single ground connection point. Not shown is the continuous ground plane under it. ...
  14. Ran into an issue - speaker/room correction is...

    Ran into an issue - speaker/room correction is normally done with a separate impulse for each channel. And I don't understand the code well enough to change it.
  15. Replies
    4
    Views
    203

    That wiring worked, but wasn't bright enough for...

    That wiring worked, but wasn't bright enough for some DACs. This works correctly.
  16. Replies
    4
    Views
    203

    Has anyone used T4 Serial+Midi+Audio with Linux? ...

    Has anyone used T4 Serial+Midi+Audio with Linux? DD4WH (OS unknown) reported the opposite problem (Audio alone didn't work).
  17. Replies
    19
    Views
    393

    I think your crystal is sharing a line with...

    I think your crystal is sharing a line with something else. I wouldn't do that.
  18. Will do once I'm done. More on DRC here: ...

    Will do once I'm done. More on DRC here:

    https://en.wikipedia.org/wiki/Digital_room_correction#:~:text=Digital%20room%20correction%20(or%20DRC,of%20a%20sound%20reproduction%20system.

    It does...
  19. Thanks (for the help and the code). I found it...

    Thanks (for the help and the code). I found it was necessary to use AudioMemory(20). Sounds good now. Might be worth using 20 (or more?) in your code.

    The goal is to do digital room...
  20. I don't use I2S at all, but restoring that rate...

    I don't use I2S at all, but restoring that rate line made no difference. A big clue - disabling all the convolution code and just taking samples, converting to float and then back also has the...
  21. I made minimal changes to use USB input and...

    I made minimal changes to use USB input and spdif3 output and I get lots of static (setup works fine without convolution). Tried two difference versions (first was 09/11/2019). Any suggestions or...
  22. Replies
    4
    Views
    203

    Linux audio device bug? + toslink on T4

    When I run this program with the USB type set to Serial/MIDI/Audio, there is silence. I change to USB type "Audio" and it works well. T4, OS is Linux Mint, Teensyduino 1.53. Is it possible to have...
  23. Replies
    19
    Views
    393

    More info here: ...

    More info here:

    https://forum.pjrc.com/threads/62921-Help-with-Teensy-3-2-DIY-Project
  24. > do Serial.flush() I've been caught by the...

    > do Serial.flush()

    I've been caught by the fact that Serial.flush() doesn't actually wait until the data is seen by the PC. For that you also need a delay.
  25. Replies
    3
    Views
    157

    Due to pin-out differences (a TCXO needs power),...

    Due to pin-out differences (a TCXO needs power), I assume this is for a custom teensy design? If so, I'd encourage you to design it to use a VCXO. This would allow software to trim for even better...
  26. Thread: audio clock slip

    by jonr
    Replies
    15
    Views
    391

    There is frequency accuracy and jitter. ...

    There is frequency accuracy and jitter. Hopefully nobody is thinking that something like a 10 ppm difference in frequency is audible (unless it causes a buffer under-run). Jitter does effect sound...
  27. Thread: audio clock slip

    by jonr
    Replies
    15
    Views
    391

    NTP works better than I guessed. I run chrony on...

    NTP works better than I guessed. I run chrony on my PC and it reports that the system clock wanders around 5 ppm fast but is corrected to .01 ppm.

    My sound card's rate is a bit off - I have to...
  28. Thread: audio clock slip

    by jonr
    Replies
    15
    Views
    391

    I'm no expert, but I see these choices for audio...

    I'm no expert, but I see these choices for audio rate sync where there is a teensy and other audio clocks:

    a) Use a shared clock source. Certainly possible if the teensy is the clock source,...
  29. Thread: audio clock slip

    by jonr
    Replies
    15
    Views
    391

    > the host is responsible for adjusting the data...

    > the host is responsible for adjusting the data rate to match the device's requirement

    Understood, and helpful to know this. But if the data is coming into the PC from some other source (eg,...
  30. Thread: audio clock slip

    by jonr
    Replies
    15
    Views
    391

    Another option would be to flip between PLL4 and...

    Another option would be to flip between PLL4 and PLL5. I don't know if that would cause any audible glitch.

    It does appear that when the crystal is exactly 24 mhz, the system will produce...
  31. Thread: audio clock slip

    by jonr
    Replies
    15
    Views
    391

    Regarding PLL4, it looks like it needs to be...

    Regarding PLL4, it looks like it needs to be stopped and restarted to change. But there are periods when an audible glitch would be harmless. For example, on startup. Ie, run for a few minutes...
  32. Replies
    6
    Views
    263

    As much as possible, switch to digital audio...

    As much as possible, switch to digital audio transmission.
  33. Thread: audio clock slip

    by jonr
    Replies
    15
    Views
    391

    audio clock slip

    Just getting started with teensy audio. I imagine that the teensy 4 derives its i2s clock from something that isn't an exact multiple of 44100. So if I'm receiving real-time audio on a PC at 44100...
  34. Replies
    8
    Views
    390

    Or convert to SPDIF/toslink output. Then you...

    Or convert to SPDIF/toslink output. Then you have all digital up to a point with no electrical link.
  35. I'd run the MCP3008 at 3.3V, reducing analog...

    I'd run the MCP3008 at 3.3V, reducing analog input voltages with a voltage divider if they are > 3.3V.
  36. Replies
    1
    Views
    137

    Using the ADC differential inputs and providing...

    Using the ADC differential inputs and providing matched input paths (same routing, same filtering, etc for both lines) is helpful.
  37. Replies
    20
    Views
    801

    I think something like MISRA C++ would be best...

    I think something like MISRA C++ would be best for beginning embedded programmers. Not just for a job, but for better (more reliable, easier to maintain, etc) programs.
  38. Replies
    20
    Views
    801

    I'm curious about your thoughts on teaching C vs...

    I'm curious about your thoughts on teaching C vs starting with C++. IMO, better not to have to unlearn bad habits.
  39. Replies
    15
    Views
    355

    It's not the case here, but if the input were...

    It's not the case here, but if the input were capacitor coupled with no resistor, the input voltage would rise to be a huge error.
  40. Replies
    6
    Views
    290

    I'd go straight to learning C++, even if many...

    I'd go straight to learning C++, even if many embedded programs are in C. It will encourage better code.

    IMO, it's important to have academic, experimental and a commitment to keep improving.
  41. Replies
    15
    Views
    355

    > Its widely used for Modular Synth Modules for...

    > Its widely used for Modular Synth Modules for input protection of digital Modules

    Looks to me like the op amp before it (rated for VCC– + 36) is providing the protection.
  42. I suspect that the software (and the laser...

    I suspect that the software (and the laser characterization) included in the evaluation kit (MAX98390EVSYS) is useful.
  43. Replies
    15
    Views
    355

    > MPC6002 ... can be used for clamping What...

    > MPC6002 ... can be used for clamping

    What happens when 5V gets applied to the MPC6002 analog input which is rated to a max of VDD + 1.0V?
  44. An alternative to getting good sound is to...

    An alternative to getting good sound is to measure the response and then fix it with equalization. Most flexible is with fast, partitioned convolution, but other methods work.

    I'll admit that I...
  45. Replies
    15
    Views
    355

    Yes, use an op-amp that is labeled "rail-to-rail...

    Yes, use an op-amp that is labeled "rail-to-rail input and output".
  46. > Does the reference ground also vary as a result...

    > Does the reference ground also vary as a result of SD card activity?

    Typically yes. But generically (T3.5?), this can be addressed by using differential inputs - one attached to ground at the...
  47. All your reading are proportional to the "3.3V"...

    All your reading are proportional to the "3.3V" rail. Which will vary with load.
  48. Start simplifying until the issue goes away. For...

    Start simplifying until the issue goes away. For example, what happens if you only write values to memory (no SD card involvement)?
  49. Replies
    499
    Views
    301,679

    OK, now step through your code in the case where...

    OK, now step through your code in the case where analogRead() returns 127 and then 128. What values do you get for pot_1 and what happens?
  50. Replies
    499
    Views
    301,679

    Say that analogRead() returns 127 and then 128. ...

    Say that analogRead() returns 127 and then 128. What do you expect your code to do?
Results 1 to 50 of 500
Page 1 of 10 1 2 3 4