Why is this a good engine?

It works very simply, easily  and stably.
The resonance frequency of the engine is not the loop resonance frequency. Mass of the resonator gives the frequency of the engine. So engine works variety of resonator mass.
We can use it easily under pressure engine!
It is very simple for model and you can buld easily.
How doec compelling thermoacoustic engine?

1. When the gas (air) is heated then it expands.
When the gas (air) colled then it shrinks.

2.The gas (air) is in the tube as a  spring.

3.The gas (air) is in the tube as a piston (mass).

Small membrane is 4 cm wide.
Big membrane is 8 cm wide.
Membranes are from thin and flexible rubber gloves:

Merkel and her companions must be very punishment!