The Emperor has commanded that I undertake a new three way design study.
The goal, as he put it, was a new box speaker with higher output capability (+ 6 dB) than the M8ta, but a similar overall approach.
I am still puzzling over his enigmatic command to find "one rule to drive them all"; he suggested searching for the clues from "the mad loudspeaker professor".
Without a solid foundation, no project will succeed, so for now I submit a proposal for the foundation element, the bass/lower midrange system.
Requirements:
Few drivers are suitable for meeting these requirements. It does not require Force sensitivity to realize there are very few possible candidates, especially given the extended midrange and sensitivity requirement.
The selected woofer is the Aurasound NS12-513A
Using Unibox and with some curve fitting of published data and T/S specifications, an LF design was derived based on the target goals:
Predicted response and Xmax limits from Unibox
The Emperor conveys his permission to use this as a subwoofer design also, for those so inclined, though it will not match the output capabilities of the true long travel drivers, and the enclosure may not be as small as some would like. On the other hand, upper bass performance and integration with other speakers should be excellent. A Force balanced dual driver subwoofer design in one cabinet will require a net interior total volume of approximately 5.5 cu ft.
For the rest of the day, I shall retire to the meditation chamber and ponder the enigmatic directions of my master and the challenges which lie ahead...
The goal, as he put it, was a new box speaker with higher output capability (+ 6 dB) than the M8ta, but a similar overall approach.
I am still puzzling over his enigmatic command to find "one rule to drive them all"; he suggested searching for the clues from "the mad loudspeaker professor".
Without a solid foundation, no project will succeed, so for now I submit a proposal for the foundation element, the bass/lower midrange system.
Requirements:
- In room response to 20 Hz @ 106 dB/1 meter each cabinet
- Enclosure volume no more than 3 cu ft
- Driver must function as full output midrange to 600 Hz, clean to twice that frequency
- No more than 100 watt drive required for specified SPL
- Sensitivity for 2.83V in the 88-89 dB range
Few drivers are suitable for meeting these requirements. It does not require Force sensitivity to realize there are very few possible candidates, especially given the extended midrange and sensitivity requirement.
The selected woofer is the Aurasound NS12-513A
Using Unibox and with some curve fitting of published data and T/S specifications, an LF design was derived based on the target goals:
- Net enclosure volume: 76 Liters
- Fb tuning: 18 Hz
- System F6: 20 Hz anechoic
- Port: 3" ID, Length = 19" flared both ends
- Lined enclosure, light stuffing
- With port blocked, operates as Q~0.5 sealed, 100 dB @ 28 Hz Max anechoic, 106 dB@ 28 Hz in room
- 100 watt drive level for full output
- Port velocity within limits at any frequency from 16 Hz to 100 Hz @ 100 watts, nominal ouptut per cabinet in room of 106 dB.
Predicted response and Xmax limits from Unibox
The Emperor conveys his permission to use this as a subwoofer design also, for those so inclined, though it will not match the output capabilities of the true long travel drivers, and the enclosure may not be as small as some would like. On the other hand, upper bass performance and integration with other speakers should be excellent. A Force balanced dual driver subwoofer design in one cabinet will require a net interior total volume of approximately 5.5 cu ft.
For the rest of the day, I shall retire to the meditation chamber and ponder the enigmatic directions of my master and the challenges which lie ahead...
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