Hi again Ian and thanks for many tips...
(p.s. I love your pict member
)
AIIIIII
I really sorry to read your post for manys reason and I feeling to start a another long long bing bang controverse...
1--- First the SLM Radio Shack have a really poor response in high frecquency... ( I remember my friend I have one maybe it ispossible to create comparaison...).
The flat response is not up to 15K it is ( in my memory below 12K)
and the lower is not good below 100 or 80 Hz...
Because the feeling of pitch or balance tonal is critical (0.2 -0.4 dB) the precision is THE difference. ut of course it is possible to feel coarse set-up in this...
the SLM distord the field response and it big eratic alteration response mesurement...
2--- Your method is classical for mesure acoustic response with minimise background interferance create by room.
3--- Unfortunately the driver is fluctuate consistently in area of freq response... So 15K is maybe 2 dB higher of average power level of this driver of maybe below couple dB... In according .4dB variation is the best set-up the methos of only one freq is too aleatory... add imprecision tool ...
4--- Well your method is explain in rane electronic crossover... and explain many tecnic for phase and SPL calibration with simple SLM... but it is really coarse adjustement and not create magical set-up...
5 the magical set-up is very expensive in money and time...
a--- big high end instrumentation and ultra high level mic (free field or and pressure field) 2 positions according to ansi or ISO standart... in regard of sweet height spot... generate pink noise (with high accuracy) and average over a 30 secor more record mesurement. (slow = 2 seconds but it is not satisfying the stabilisation of low frequency for accuracy mesurement...)
b--- more records positions more accurate mesurements: mic is keep the node and modal response room, so the many different positions is cancel this effect by averaging result many positions...
Of course you catch the response room and it is important factor, distance and angle and plane surface modifying response curve and it is important to set-up Lpad in this reagrs for better fla response possible... not theorical driver response....
Of course the more sofistication analyse modal response room expose where specially bad or poor response area... If you have push the button , the treatment of echo and other modal parameters room influence the result...
Finnaly the level of finest FFT analyser or RTA expose 1/24 oct is really surprise response in regard of 1/3 octave... and discovery the value is in realy just a small peak frequency to boost result Consequence : more details more precise value...
But YES I go in your point of views, the subtil tune-up L-pad reveal the finest of nature of speakers and sound...
After works this set-up, I realise many news details in music, subtility sound, many high frq. details but L-pad is lower than before perform test !!!
Best regards,
Jean.