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Ok thank you for this info.
I did not know that it was necessary to specify the type of a number on the other hand for a variable it seemed obvious to me

float amplitude = 1.0;
float dB = 20*log10(amplitude);
Serial.println(dB);

float invertLog = exp10f(((float)dB) / 20.0f);
invertLog = invertLog;
Serial.println(invertLog);

that works well...

I corrected the factor of 2, thank you

on the other hand I still can not find the value after convertion:


float amplitude = 1.0;
float dB = 20*log10(amplitude);
Serial.println(dB);
...

I don't understand why when I connect the waweform object to the peak object, I get 6dB with an amplitude set to 1.0?
to get the dB, I do:



wavefom1.amplitude(1.0);
....
while...

Hello,

I want to change the amplitude of the waveForm signal from a value in dB.
I know how to transform the level into dB : 20 * log10 (level * 2),
but not the other way around.

example: ...

I try the library fft4096 found here : https://forum.pjrc.com/threads/42221-Audio-Library-and-4096-point-FFT-on-Teensy-3-6
this seems good to me for my application, I will now think about your advice

thank you

I realize that if I want to put 1 khz roughly half of the screen (x = 320/2 = 160px), the precision will not be good because of the insufficient number of bins (512 for 22Khz, so 23 for...

for the x axis I thought to force the values ​​that interest me in an array because if I use an exponential function to draw the axes because I think that I will not have the precision between 0 and...

Hello,
I made my first spectrum analyzer displayed on the ILI9341 using AudioAnalyzeFFT1024.
I would like to display the frequency axis logarithmically.
Here, for example, are the graduations:
0...

thank you for your comments.
here is the wiring that works for me.

(I did not use the T_IRQ pin)

I used the libraries: ILI9341_t3.h and XPT2046_Touchscreen.h

#define TFT_DC 3
#define...

thanks for your reply.

Good news therefore for the Reset pin, a saved pin!

First learning tests (as a reminder I am a beginner):
TFT_CS = pin 0
TFT_DC = pin 3
TOUCH_CS = pin 1
with the...

good idea the multiplexer.
What is the tft reset pin used for? because I see that it can be connected directly to 3.3v which saves a pin.

a solution to gain pins would be to deport the commands...

I will try several wiring to operate the SD card, the touch screen, the audio card and the screen.

To see more clearly with the use of pins, I made a diagram for myself, I will complete it with...

Hello,

I just received the ILI9341 and would like to connect it to the Teensy 4.0 with the Rev D audio adapter.
I tried without the audio card, respecting the wiring indicated on PJRC, it works...

thanks for these links!

in fact I also want to also measure the sound insulation of windows, doors, discover the world of acoustics and Teensy.
It's more about discovery and learning than a real...

Where can I find your project on github ?

I don’t think I need phase information (I’m a newbie, i’m not shure of what I can do with phase information)

great project, I like it, it gives me new DIY ideas :)

can the code be visible?

awesome ! :)

is this ESP on the last video?
is the audio stream coming from wifi?

OK, I haven't tried it yet (I'm getting the TFT this weekend).
thank you for your advice

so if I summarize, it is not possible to replace the SPI BUS with a radio solution, but for a small volume...

you're right, the screen is to small, max 320 bins in landscape format (1 bin= 1 pixel)

for the test results yes it should work, but for the FFT (spectrum analyzer), I don't know if it is possible to send on the air the 512 bins values ​​very quickly to display them on the TFT?

the sensor is the microphone, if it is possible to deport it and send the audio stream by air? (without going through a wireless microphone system but with a module that integrates well with the...

it is not an economic problem (the TFT costs 5 dollars in china), but rather ergonomic.
If I want to take measurements on the Teensy, it is convenient for me to have the result several meters away

ok I understand, maybe that's why I can't find a screen of this size with an I2C bus

I'm afraid of having to directly link the TFT to the teensy
unless I'm wrong but no protocol will be as fast...

what is the speed of what part?

I am building a speaker frequency response analyzer, so I generate sounds (20hz to 20khz) in the loudspeaker to be tested, and I measure the signal level with the microphone.
So I need to filter the...

my code allows only 513 taps, can you show me yours ?
thanks

Hello,

My plan is to deport the TFT display to make the screen universal for various applications.

23211

The connection between the Teensy and the screen could be by radio or by wire link.
...

With convolution ?

thanks for your help
i finally found the convolution filter with more coefficient and steeper slopes
https://github.com/bmillier/Teensy-FFT-Convolution-Filter

yes I saw that there is a lot of electronic diagram with the op amps, I will look at that.

thank you all very much for your help and your time

Thank you for your answers
is it not possible to reduce the processing time of 2.9 ms by reducing for example the bandwidth? (for example: 200hz- 2khz instead of 20hz-20khz)?

thank you for your reply

my experiences (see my thread) show that there is indeed a synchronization to be done.
Indeed, when I go through "amp1" and "amp2", the sync seems to be made between the...

By connecting the two channels of the oscilloscope on L and R of line Out, it works well, the signals are well opposite at 180 ° (see the image below)

23182

But if I plug in the oscilloscope...

Hi enphoti

i have a similar project (https://forum.pjrc.com/threads/65777-invert-phase-audio-signal?p=266086&posted=1#post266086), but it doesn't work for the moment;

Did your code finally...

23180

ok, now can you tell me :
- where i connect my audio signal (sinusoidale 1khz with an external generator) : left or right or both line in ?
- where i connect my oscilloscope : left or...

I understand the 1st line connection, but I’m not sure for the 2nd : what is «*I*» on the 2nd line ?
(Sorry I’m a newbie).

I only have one audio source (microphone or low frequency generator)

if I understand correctly, I put an audio object (microphone), connected to a delay object, then then two mixers?

Hello,

I would like to reverse the phase of the audio signal (180 °) to experiment around the cancellation of sounds.

I tried with a mixer to set the gain to -1 (i tried too with the amp), but...

yes this is the first thing i tried but after i tried a 250 array that didn't work .. has anyone tried?

ok, i understand, thank you.

is it possible to increase the number of taps ? (more than 200), i've tried in filter_fir.h to set 400 instead 200, but it doesn't work with arrays with more than 200...

Thank you for your answers.

I tried differently with another software "rePhase" more complete and easier to use

This software gives me coefficients in float.
To process these floats on the...

Hello,

I am a beginner in the world of Teensy, and I bought a version 4.0 + the audio adapter.
I want to experiment audio filters (bandpass, high pass, low pass).

For this, I want to use an...