Looking for help making sound of a train horn

[otiv-willem-vanhulle]

Hi, thanks for making this library publicly available.

I am recreating the sound of a train using your library but looking for help.

I have written the following code to reproduce the main frequencies:

    let train_frequences = (organ_hz(452.20) >> delay(0.1)) * lfo(|t| downarc(0.5 * t))
        + (organ_hz(602.93) >> delay(0.2)) * lfo(|t| downarc(0.5 * t))
        + (organ_hz(624.46) >> delay(0.1)) * lfo(|t| downarc(0.5 * t))
        + (organ_hz(646.00) >> delay(0.05)) * lfo(|t| downarc(0.5 * t))
        + (organ_hz(689.06) >> delay(0.1)) * lfo(|t| downarc(0.5 * t))
        + (organ_hz(710.60) >> delay(0.2)) * lfo(|t| downarc(0.5 * t))
        + (organ_hz(882.86) >> delay(0.3)) * lfo(|t| downarc(0.5 * t))
        + (organ_hz(904.39) >> delay(0.4)) * lfo(|t| downarc(0.5 * t))
        + (organ_hz(925.93) >> delay(0.4)) * lfo(|t| downarc(0.5 * t))
        + (organ_hz(947.46) >> delay(0.4)) * lfo(|t| downarc(0.5 * t))
        + (organ_hz(1076.66) >> delay(0.4)) * lfo(|t| downarc(0.5 * t));

However, I am afraid that I am doing something wrong.

The sound that I would like to recreate can be found on https://www.youtube.com/watch?v=9Ptcd5O1i7E

I have computed a spectrogram as well.

From this spectogram I found the main frequencies and I could kind of reproduce them. I have adjusted the delays a bit, so that it sounds more like the sample.

However, it still sounds far from the sample. Am I doing something wrong here? On the spectrogram I see a lot of frequencies in between the loudest ones. Should I add some kind of noise to make it more realistic?

[andrew-otiv]

(Colleague of Willem) This is more precisely the sound we're mimicking:
https://www.youtube.com/watch?v=f8acEMFSZvI