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In the Forum: Horn-Loaded Speakers
In the Thread: New superlative horn build - ESD acoustic
Post Subject: Lower flux simulationPosted by martinshorn on: 5/20/2018
Now the same graph black...
Equivalent to lower flux, i increased the Qe from 0.15 to 0.35 and the Qm from 3 to 7. Result in red curve. Only worse, in all aspects. Edgar Bruce's theory that TSP does not matter and flux cant be high enough seems to remain true here, as the horn (like Edgar sais) mass load outrules the drivers (electrical relative) suspension (to some extend).
The green curve shows same driver as red but with 40 liter volume on the back (before was 10 liter). That should give idea about back ventilation, lower fs, softening suspension etc. the lowend is slightly better, though actively controlled by filters it wont make a difference at the end (apart from some milivolts less input below 40 cycles).
This reminds me on some white papers from JBL saying (like everyone but i expect JBL to have it tested & proven) the backchamber of driver should always be as small as possible. Also Edgar wrote once smaller back chamber gives deeper base. Which sounds rather like an perceived difference. In fact, smaller backchamber as you see increases fs and Qt. Which means u gain 1 dB in upper bass (explains Edgars deeper bass perception) but you loose many more in the deep low end. So to me looks like the bigger the rearchamber the better.
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