Isn't there another (hidden) bonus for achieving lower box losses (QL) ?

[Ian Mackenzie]

Well l would not call this a dead thread yet.

With local domestic engagement with building my new castle almost out of way and tradesmen everywhere l hope to do some simple measurements concerning QL.

In a simple test and learn l can import LMS data into BassBox and compare the simulation to the actual measurement.

Using a ground plane measurement technique l can get a fairly high resolution bass response curve with LinearX LMS
I may also do a pit test.

(It might piss off the local natives too)

Then introduce losses with a hand drill to an enclosure and re measure.

I have several drivers as candidates Jbl 2245, 2235, 2214, 2216nd and a AE15M for testing
I am interested in the audible threshold of QL losses?
Then attempt to evaluate is it the fall in spl or the misaligned function (noise from leaks, ripple etc causing audible threshold ?

There is an Australian scientist Witold Waldman that l will try and contact for insights.
Waksman authored a loudspeaker program and previously provided me some papers on LF hearing thresholds.

Another local developer Bogdan Raczynski who owns Soundeasy might have some insights.

We know the theory but under what circumstances and applications is it likely to impact on LF spl, LF extension ?

[RMC]

No time for this in the near future as I'm up to my neck in Electro-Voice documents writing part 3 of my article on E-V/Keele low-frequency "Step-Down Mode".

The only thing I may add is that North Reading Engineering says "The magnitude of QL must be determined after the enclosure is constructed by analyzing the motional impedance of the driver mounted in the enclosure. (...) The driver motional impedance is effected by QL. As shown in the graph right, as QL increases, so too the motional impedance measured at the voice coil." The graph left showed response curves as a function of the enclosure leakage losses (different QL values).

I'm glad I printed that juicy page in 2014, since then they have re-done their web site and no more access to their interesting tech library anymore, plus everything seems copyrighted now. northreadingeng.com

Richard

[Ian Mackenzie]

Well l can very accurately measure that during the test.

Years ago l did the whole Bullock QL process several times manually.

It was too hard.

This time l will export the data into excel and write a macro .