Jzagaja,
If we use drivers optimized for a 20L 40Hz Fb, a 30Hz Fb enclosure will be undersized, rolling off the low bass 3-6dB compared to the "normal" flat response 40Hz Fb enclosure. The 50 & 60Hz FB enclosures will be oversized, wasting space, weight and materials.
Each will require separate low pass filters to prevent over excursion below Fb.
Each would require different equalization to optimize frequency response.
This would require four separate amplifier and processing channels to implement, potentially costing four times as much.
The output from 30 to around 38Hz will basically be that of only one woofer, the output in that range will be 12dB less than if all four cabinets used an Fb of 30Hz.
At 1000Hz, a -10 dB reduction in SPL sounds approximately half as loud, while at 30Hz, just a -5dB decrease in SPL sounds half as loud.
Four times the processing and amplifier costs to sound about 20% as loud in the low bass, not a good idea.
Art
If we use drivers optimized for a 20L 40Hz Fb, a 30Hz Fb enclosure will be undersized, rolling off the low bass 3-6dB compared to the "normal" flat response 40Hz Fb enclosure. The 50 & 60Hz FB enclosures will be oversized, wasting space, weight and materials.
Each will require separate low pass filters to prevent over excursion below Fb.
Each would require different equalization to optimize frequency response.
This would require four separate amplifier and processing channels to implement, potentially costing four times as much.
The output from 30 to around 38Hz will basically be that of only one woofer, the output in that range will be 12dB less than if all four cabinets used an Fb of 30Hz.
At 1000Hz, a -10 dB reduction in SPL sounds approximately half as loud, while at 30Hz, just a -5dB decrease in SPL sounds half as loud.
Four times the processing and amplifier costs to sound about 20% as loud in the low bass, not a good idea.
Art
It could be done but I don't see the point. I disagree about the cabinet size issue.
If you took a 1ft cube and 50mm diameter port: a 250mm length would give you 32Hz, 150mm: 42hz, 60mm: 55Hz
I's sure about the stack either. My front subs are tuned to 50Hz and the rear sub 35Hz. In practice the rear sub rarely gets used.
I don't see amplification as a major problem. A single TPA3116D2 will cover four drivers.
If you took a 1ft cube and 50mm diameter port: a 250mm length would give you 32Hz, 150mm: 42hz, 60mm: 55Hz
I's sure about the stack either. My front subs are tuned to 50Hz and the rear sub 35Hz. In practice the rear sub rarely gets used.
I don't see amplification as a major problem. A single TPA3116D2 will cover four drivers.
This is what I was thinking - different box size and tuning. Acoustical sum.
Here we see multiple TL isn't smooth:
MDD Multi Delays Diffraction (Multi TL, omnidirectional, single drive, ...)
Here we see multiple TL isn't smooth:
MDD Multi Delays Diffraction (Multi TL, omnidirectional, single drive, ...)
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