Sounds like good results already, with probably a lot of room for improvement.
We need specs and at the very least some audio of the distortion at full power
Alternative reasons:
1. The driver is loose, rattling on its own.
2. The driver is catching on the grille at low frequency xmax
3. The driver is catching on the PCB at low frequency xmax
4. The driver is front-loaded by the grille, turning it into a compression-driver
5. The front case as a baffle is a problem
6. The front waveguide is a problem
7. The front speaker grille is a problem
8. The back waveguide is a problem
9. The diffraction against the PCB is a problem
10. The space for the back of the driver is a problem, could be standing waves, could be many things
11. The openings for ports, battery compartment seal (etc) in the back of the case is a problem
12. The case dampening is a problematic
Many of these lead to a problem for the amp, and
13. The amp has a problem with normal loads
To troubleshoot
free air
- try the driver outside the case, radiating into full space
Provided we get this far, and assuming ideal working conditions, try the following first with the driver sealed into place with silicone along its edges, then again like that, only now with the front grille completely removed.
dipole
- use only the upper lid as a baffle
closed case
- sealing off the back, try it in infinite baffle, needs an area over VAS, use something like a half a kinder-egg with dry silicone along the edges to push it closed over the back of the driver. Try multiple shapes by crunching it or finding something else
bandpass
- assembling the case, try it in the case
bandpass 2
- add dampening material to the sealed case.
bass-reflex
- try sealing off some but not all off the openings in the case
Could also try the GPD drivers or pandora drivers in known to work or these conditions, or,
move the pyra drivers to the pandora or the GPD.
If you do a frequency sweep you can see what happens to the resonant frequency for all of these things.
Here it is at 600Hz, regular driver
From what i could see on the pictures it looked like the back volume was almost completely sealed.
The low frequencies taper off, and the high frequencies are lost, more alarmingly;
It moves that impedance peak into where it isn't supposed to be, and sharpens it. Meaning the dampening factor is off there seen by the amp. It also moves to a higher frequency, The difference between that peak is greater as a result relative to the other frequencies. If the driver is lost beyond linear excursion, that isn't good, and its
especially not good given you can throw any combination of the frequency-band at it while its there.
QMS is way above spec, leading to
QES being all over the place, meaning intermodular distortion
QTS is down for everything above resonant frequency
Is it a ribbon driver, or am i missing something?