No, but I can measure that stuff....
Minimus 7 Loudspeakers - Measurements
- Thread starter Zilch
- Start date
Tweeter model SD 60 impedance does not go through zero phase at resonance, so WT2 won't call it "Fs" and calculate T/S parameters. Perhaps CLIO will, but I'll have to study up how to do T/S with it. Re = 7.3278 Ohms:
Woofer model 1218 free-air impedance and Q, Fs T/S parameters:
Woofer model 1218 free-air impedance and Q, Fs T/S parameters:
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You da man, Z. Please note that for the values below I used the XO3 (Harristech) estimator and ballparked values from the tweeter impedance curve to get a working version of T/S params for it. I guessed Fs at 2200Hz and Zmax at 11 ohms. The program came up with Qms of 5.989, Qes of 11.96, and Qts of 3.991. If you get CLIO to spit out real numbers let me know and I'll correct for it.
Now, try this out and see what you think...
3rd order Butterworth at 5500Hz on the tweeter, C1=2.7uF, C2=8.2uF, and L1=.15mH.
2nd order Butterworth at 2k on the woofer C3=8.2uF and L2=.7mH
edit: dorking around for a lower/cheaper parts count...
3rd order on tweeter 2.2uF, 7.5uF, .15mH
1st order on woofer .5mH
cuts a few bucks out and while not quite as pretty, it's not too bad (2nd graph)
Ray
Now, try this out and see what you think...
3rd order Butterworth at 5500Hz on the tweeter, C1=2.7uF, C2=8.2uF, and L1=.15mH.
2nd order Butterworth at 2k on the woofer C3=8.2uF and L2=.7mH
edit: dorking around for a lower/cheaper parts count...
3rd order on tweeter 2.2uF, 7.5uF, .15mH
1st order on woofer .5mH
cuts a few bucks out and while not quite as pretty, it's not too bad (2nd graph)
Ray
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There goes my weekend! 
[I'm trudging piecemeal through the known mods first here, though.... :yes: ]
Edit: Recap does essentially nothing. Stock NPE cap was 4.88 uF, kit cap is 4.68 uF (Cyn).
Kit (Blk) partially mitigates the 8 kHz peak with its lowpass and Zobel, and reduces the driver interference between 5 and 7 kHz, but by keeping the stock highpass, fails to address the other major peak at 3 - 4 kHz:
It's counter-intuitive, but the tweeter's making the lower peak. See the individual driver curves at #54 and #59, above. The HF is also running 4 - 6 dB too "Hot," generally, and would be improved by attenuation. I'll try the kit with attenuation once I get "outside the box" here. I've got too much stuff crammed in there right now.
We'll find out if the first Speaker Builder mod does a better job with all of that, next.... :yes:
[I'm trudging piecemeal through the known mods first here, though.... :yes: ]
Edit: Recap does essentially nothing. Stock NPE cap was 4.88 uF, kit cap is 4.68 uF (Cyn).
Kit (Blk) partially mitigates the 8 kHz peak with its lowpass and Zobel, and reduces the driver interference between 5 and 7 kHz, but by keeping the stock highpass, fails to address the other major peak at 3 - 4 kHz:
It's counter-intuitive, but the tweeter's making the lower peak. See the individual driver curves at #54 and #59, above. The HF is also running 4 - 6 dB too "Hot," generally, and would be improved by attenuation. I'll try the kit with attenuation once I get "outside the box" here. I've got too much stuff crammed in there right now.
We'll find out if the first Speaker Builder mod does a better job with all of that, next.... :yes:
Attachments
skywave-rider
Slumming in Akihabara
skywave-rider
Slumming in Akihabara
I'll try to catch up to you by tomorrow.
These were vinted by RS approx. 28 years ago, maybe.
External:
Two screws remove the input terminals and stock crossover from inside the Minimus 7, shown here (left) with the Speaker Builder #1 mod still installed.
I replaced it with gasketed fiberboard having two small holes for bringing out the woofer and tweeter leads, in anticipation of prototyping the circuits RayW suggested above.... :thmbsp:
Two screws remove the input terminals and stock crossover from inside the Minimus 7, shown here (left) with the Speaker Builder #1 mod still installed.
I replaced it with gasketed fiberboard having two small holes for bringing out the woofer and tweeter leads, in anticipation of prototyping the circuits RayW suggested above.... :thmbsp:
Attachments
Attachments
skywave-rider
Slumming in Akihabara
skywave-rider
Slumming in Akihabara
My crappy RTA correlates with your real measurements pretty well.
They are made in Japan, Minimus 7, cat #40-2030c
The QC sticker says: no. 6737 1A9
The other one is painted over, don't know if they are similar vintage.
Staying tuned....