For what it's worth took these measurements of the final FINAL crossover / L-pad arrangement...
Except I was fairly sure that that was not what I was hearing. I was genuinely not hearing a 25dB drop from 130Hz to 140Hz. Was something at fault...? My ears perhaps...? I repeated the measurements and got the same results.
Throughout all of these measurements I have had the iPhone in exactly the same place: Sitting next to me on the arm of the sofa with the microphone pointing towards the speakers. So the microphone is about 40cm in front and 30cm below my right ear. Not a million miles away.
But this morning I did wonder if that distance enough to place it into a different room acoustic to one, or both, of my ears. So, I re-did the measurements, this time holding the iphone against my chin, with the mic pointing towards the speakers. These are the measurements with the iphone in that new position; closer to my ears.
Weirdly different. Pretty much right across the range! Moving the phone just a foot seems to make a >20dB measurable difference at 140Hz! I suppose it's unpredictable and dramatic room acoustics.
And, I suppose that's one reason why measurements, in general aren't that helpful. :-D
Ben load down this SIM program it is free and fun. Oh some things it can get wrong i.e. Resonant PSU design at 1MHz and other noise stuff, but for basic stuff like DAC etc it is OK
Comments
;-)
Except I was fairly sure that that was not what I was hearing. I was genuinely not hearing a 25dB drop from 130Hz to 140Hz.
Was something at fault...?
My ears perhaps...?
I repeated the measurements and got the same results.
Throughout all of these measurements I have had the iPhone in exactly the same place: Sitting next to me on the arm of the sofa with the microphone pointing towards the speakers. So the microphone is about 40cm in front and 30cm below my right ear. Not a million miles away.
But this morning I did wonder if that distance enough to place it into a different room acoustic to one, or both, of my ears.
So, I re-did the measurements, this time holding the iphone against my chin, with the mic pointing towards the speakers.
These are the measurements with the iphone in that new position; closer to my ears.
Weirdly different. Pretty much right across the range!
Moving the phone just a foot seems to make a >20dB measurable difference at 140Hz!
I suppose it's unpredictable and dramatic room acoustics.
And, I suppose that's one reason why measurements, in general aren't that helpful. :-D
Have fun.
https://www.analog.com/en/design-center/design-tools-and-calculators/ltspice-simulator.html