I'm attempting to make a fake choir sound out of sine waves. For the past 5 years, I have been playing around with onlinesequencer.net. It's a very simple and limited online midi music making website with around 50 preset sounds you can use, and some features like different types of distortion, EQ settings, and reverbs, as well as being able to set specific note volumes, detune instruments to any value, etc.
I have an MP3 file of the choir sound I am looking to recreate with the overtone series, but I am looking for a way that I can visualize the overtones and the different volumes of each one, so that I can attempt to recreate the sound on the piano roll, using the 8-bit sine instrument. I would place each overtone at its approximate position on the chromatic scale, and have a hopefully pretty similar version of the choir sound.
I've tried spectrograms, however none that I have used have specific volume values for each overtone, only colors with no key that says what they really mean. If anyone knows a way I can find these volumes, or have a better way of going about this, I would greatly appreciate it. Thank you