Looping questions

[souravlal]

The ESP32 audio kit outputs humming sound while playing notes. I have connected an esp8266 to send MIDI data to ESP32 audio kit. IO18 is used to receive MIDI data, ground is connected to ground. I have tried different amplifiers and power supplies, ground connections are ok , I don't think is a ground humming also don't think is a hardware problem. The humming sound appears only when the kit starts to play sound, when playing no tones there is no problem.
The tone also doesn't sound like a bottle sound its more like a drum sound, also the sound output is very low, even though I put the amplifier to maximum volume. I also tried the speaker output of the kit both channels are not working.

I used this code for esp8266:- https://github.com/rjobidon/esp8266-midi-out

[Slider2732]

Quick answer - have you tried moving the Audio Kit jack plug in and out slightly?
My set up has the 3.5mm plug halfway out, otherwise I was getting hum. Tried headphones and out to my audio recorder, both plugs needed to be halfway out.
I think it depends on whether you have a 3 ring plug or 2 ring plug.

[souravlal]

But in your videos you are playing your MIDI controller with Audio-kit, it doesn't feels like there is a speed increase/decrease with different notes.

Sampler_LoopAll(1, 1)
Can I call this function anywhere in the code?
What is (1,1) parameters in this function?

[marcel-licence]

void Sampler_LoopAll(uint8_t index, float value)
{
    if ((value > 0) && (lastActiveRec != NULL))
    {
        float sampleLen = (lastActiveRec->end - lastActiveRec->start);

        lastActiveRec->loop_start = 0;
        lastActiveRec->loop_end = sampleLen - 1;

        Status_ValueChangedFloat("len", lastActiveRec->end - lastActiveRec->start);
        Status_ValueChangedFloat("loop_start", lastActiveRec->loop_start);
        Status_ValueChangedFloat("loop_end", lastActiveRec->loop_end);
    }
}

[marcel-licence]

You should call NoteOn before to get this sample as active sample.

[souravlal]

Is setting loop time manually means this project will work like any normal keyboard @ any notes?
Don't you feel the difference in duration of each notes while playing and doesn't it effect your keyboard playing?

[souravlal]

@marcel-licence I have called "Sampler_LoopAll(1,1)" function after I called note on for MIDI note number 100 @ channel 2. But it doesn't seems to loop the sample l, in fact it triggers it multiple times. Here it how it sounds like:-👇

With.Sampler_LoopAll.@.MIDI.note.number.100.mp4

[Slider2732]

I've had great success looping using the pots via MIDI. It takes a while to get the sound without clicks etc, but works great. Sounds like yours is repeating the whole sample, not from and to somewhere in the middle.

A workaround, is to use the reverb and delay effects... the ear hears the time constants of the effects, after recognising the sound. As such, the note lengths are helped with a form of obfuscation.
For example, the Pet Bottle sample - your ears hear the bottle sound, but don't really have a reference for the length of that sound (unlike say a finger snap). With something staccato it would make little difference and is where the onboard envelope shaper can help too.

I will say, sampling has always been that way to my own ears, shorter version higher up, longer down low, due to the amount of samples being played. A 1 second sample can last 30 seconds on the opposite end. Same since the 1980's!
I'd think the sustain would be the parameter to adjust for constant length, but it's tough to get loop points correct 'on the fly'. Have to wonder though, if a loop point is found 'by ear' similarly to how Marcel has the code set up now, whether those same points could extend and truncate based on the keyboard notes being played. Sustain would be set with a specific amount of those loops per key, like a reference table.

For your 6N138 troubles, have you tried car boot/yard sales in the local area? Old telephone gear, routers, PC power supplies or modems may well have them onboard. A bit of desoldering salvage can sort many such supply troubles :)

[souravlal]

Having said that with the default "Pett_bottle.wav" sample there is no duration issue for different notes. I have played it using MIDI note number 60 and 100, and here it how it sounds like:-

Pett_bottle.wav.@.MIDI.note.number.100.mp4

Pett_bottle.wav.@.MIDI.note.number.60.mp4

But its a different story while I use my own samples, like I mentioned above.

[souravlal]

@Slider2732 Whatever samplers I have seen does not change speed of notes @ different pitch.
You said about looping, please help me, how can I change this? By doing this the duration(speed) problem can be fixed? Can it be done inside the code? Or is it done through switches attached using the help of display? Does setting loop needs to be done for each and every samples if I am playing from SD card?
MIDI circuit is not an issue, I can fix that out with some experiments, but what I struggle with is the software part(code).

[souravlal]

@marcel-licence How do the default sample "pett_bottle.wav" plays without speed issues at all notes? Please let me know.

[souravlal]

Also a custom sample I have loaded to PSRAM stops playing without calling note off command.

[Slider2732]

I've not used pro modern samplers at all, experience is only with the Casio SK-5 or other vintage stuff.
If time stretch is a common thing on pro gear then that's cool!
Though, my Zoom R8 recorder can stretch anything, to time or tempo. But, it takes 3 or 4 seconds to do so, for 1 sample... I expect it's all far too CPU intensive for real time on an ESP32, latency would be epic.

No idea of how to implement the code, unfortunately.
Was just a time stretch idea :)

[marcel-licence]

I am preparing a video soon 1-2 weeks if I can find enough time =) I am sure that will help you because I've found a way to integrate sf2 soundfonts using a little workaround

[souravlal]

Oh, looking forward to that. Good luck.

[marcel-licence]

This video: https://youtu.be/Accf54fJn6U may answer the questions regarding the setup of samples

[souravlal]

@marcel-licence Is it possible to set loop for whatever samples I want to put in to the sd card, using this technique?

[marcel-licence]

Sure this method is not limited to this example. You have only the limitation that the sampler project can only use one sample per instrument. The soundfont in general supports multiple samples per instrument for different pitches and velocity values. That is not supported by the sampler project. Another limitation is the 4MB PSRAM. The wav file shall be smaller than 4MB.