The afterburner is a difficult, but not a mystical thing.
The colour of the flame, lenght of the flame, the width of the flame, the number of the shockwave rings, are came from the main parameters of the engines, and the atmospherical conditions.
Look the differences of F-15C - F-15E.
Basicly the F-100PW100/200/220 and the PW229 is same, but the PW229 has an improved afterburner, more specific fuel consumption, higher fuel eater system, so the flame lenght, ring numbers is different.
Check every pic from Lakenheath.
The numbers of the rings at the F-15C are six or seven, but at the Strike Eagle are nine to ten.
Or look the MiG-29.
In daytime the flame is almost invisible, or we can see 3-4 rings.
In low level at slow speed, but darker background we can see 4-5 rings, but if we check the high altitude pictures, we find a longer 6-7 rings more blue tone flame.
Why? Because, the plane fiy at high altitude, lower pressure atmosphere, and the nozzle pressure ratio is higher than the see level.
Check the Su-27 family.
The flame lenght is almost long like the famous afterburner of the MiG-23, the ring number is higher than 9, the sound is a nice mixture of the deep earthquake like Viggen, because this engines use a big airflow compressor, 115 kg/sec air, but the thin and long flame produce the very special, high frequency noise.
Yes, my absolute amateur opinion, the sound of the flame is build by next parameters.
The higher ring numbers produce the higher frequencies, SR-71 was the winner.
The wider flame came from higher fuel consumption, and higher airflow, the higher width produce the deeper sound.
Viggen is the winner, but the absolute winner is the Tu-160.
The amplitude of the noise and the distance between the rings have some connection.
If the nozzle pressure ratio (high altitude-low air pressure, or low altitude high speed pass-nor,al air pressure) goes higher, the distance of the rings, and the whole flame lenght are goes longer.
Bye