In spite of the lovely Northern California weather this weekend, I've been sequestering myself in the "audio laboratory", because otherwise nothing would ever get done!
Today I finished assembling and voicing the first crossover set for the MkIII version of the M8.
As a refresher, see the cabinet design below.
The test box setup isn't anywhere near as pretty yet!
And the front panel dimensions are wrong for the designed baffle step correction in the crossover as designed on the computer. However, it's enough to check the simulations and dial things in a bit.
So far, things are looking pretty good with minimial tweaking; and they sound the best yet of the three versions.
This is the MLS response, gated to elminate most room reflections, but to get a response window down to 200 Hz, I'm still picking up the first early reflections. This in on the woofer axis, 1 meter from the speaker.
This second cuve is an RTA plot at 2 meters in room, 30 degrees off axis. This correlates with off axis room power response. Due to the non-ideal positioning of the speaker for the measurment, a room null is obvious in the 40-45 Hz region, plus a variety of other ripples from reflections (these aren't setup in a normal listening position). For 30 degrees off axis, the overall response window is quite smooth, excepting the bass nulls, out to 15 kHz. This is very pleasing in room response to me.
What these curves don't show is the overall level of articulation in the midrange and highs. The crossover point, BTW, is 1.5 kHz at roughly 48 dB/octave; the tweeter resonse is down over 30 dB before reaching the Fs. Below is the basic tweeter response before voicing the filter network, showing the LF roll off.
This, and the pistonic behavior of the woofer in the range it's being used contribute to a very clean sound, even in the less rigid test box.
Back to work- on the new pair of cabinets!
Regards,
Jon
Earth First!
_______________________________
We'll screw up the other planets later....
Today I finished assembling and voicing the first crossover set for the MkIII version of the M8.
As a refresher, see the cabinet design below.
The test box setup isn't anywhere near as pretty yet!
And the front panel dimensions are wrong for the designed baffle step correction in the crossover as designed on the computer. However, it's enough to check the simulations and dial things in a bit.
So far, things are looking pretty good with minimial tweaking; and they sound the best yet of the three versions.
This is the MLS response, gated to elminate most room reflections, but to get a response window down to 200 Hz, I'm still picking up the first early reflections. This in on the woofer axis, 1 meter from the speaker.
This second cuve is an RTA plot at 2 meters in room, 30 degrees off axis. This correlates with off axis room power response. Due to the non-ideal positioning of the speaker for the measurment, a room null is obvious in the 40-45 Hz region, plus a variety of other ripples from reflections (these aren't setup in a normal listening position). For 30 degrees off axis, the overall response window is quite smooth, excepting the bass nulls, out to 15 kHz. This is very pleasing in room response to me.
What these curves don't show is the overall level of articulation in the midrange and highs. The crossover point, BTW, is 1.5 kHz at roughly 48 dB/octave; the tweeter resonse is down over 30 dB before reaching the Fs. Below is the basic tweeter response before voicing the filter network, showing the LF roll off.
This, and the pistonic behavior of the woofer in the range it's being used contribute to a very clean sound, even in the less rigid test box.
Back to work- on the new pair of cabinets!
Regards,
Jon
Earth First!
_______________________________
We'll screw up the other planets later....
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