Just stumbled upon the site from Kvålsvoll Design, and their Compact Subwoofer Horns.
https://www.kvalsvoll.com/Articles/CompactSubwooferTechnology.htm
Looks like very solid engineering.
Getting 110 dB @20 Hz from a 70 liter horn box. Not bad at all!
They are employing tuned "pipes" to dampen resonances, e.g. see the insides of the T140.
Like the shape of e.g. the V6, which would make a very good pedestal og lower part of a 3 way, with the V6 + say a 6.6-8 inch mid and a horn tweeter!
https://www.kvalsvoll.com/Articles/CompactSubwooferTechnology.htm
Looks like very solid engineering.
Getting 110 dB @20 Hz from a 70 liter horn box. Not bad at all!
They are employing tuned "pipes" to dampen resonances, e.g. see the insides of the T140.
Like the shape of e.g. the V6, which would make a very good pedestal og lower part of a 3 way, with the V6 + say a 6.6-8 inch mid and a horn tweeter!
Attachments
If you look at the graph of the system in a 70l enclosure it says 56Vrms ... this is about 400 W into 8 ohms
Not sure what power is needed for the T140 to reach 112 dB/20Hz .... you have to look a bit more for that 😉
But I think this is really not the point ... power is cheap today, and as they use Pro drivers, the needed power I think will be reasonable .. the point is taht you can get quite high spl from a relatively small box at low frequencies
Another cool feature of these designs is the use of tuned damping horn channels ..... look at how a resonance around 70 Hz is dampened by ca 10 dB
1m/2pi means free field, with the speaker standing on a plane/ground
Not sure what power is needed for the T140 to reach 112 dB/20Hz .... you have to look a bit more for that 😉
But I think this is really not the point ... power is cheap today, and as they use Pro drivers, the needed power I think will be reasonable .. the point is taht you can get quite high spl from a relatively small box at low frequencies
Another cool feature of these designs is the use of tuned damping horn channels ..... look at how a resonance around 70 Hz is dampened by ca 10 dB
1m/2pi means free field, with the speaker standing on a plane/ground
Last edited:
"Horn box" is a misnomer, the graph is from a simulation of the long port bass reflex enclosure, 70L would be the chamber volume, the port would occupy a similar volume. "the air volume inside the damped channel adds to the system internal volume".
The box is much larger than 70L.
At the Fb (box tuning) ~20Hz, the driver's excursion would be at minimum, nearly all the output from the port.
At 30Hz, the port contributes +6dB output to the direct radiator.
The excursion or SD of the driver is not specified.
Above 80 Hz, the port only contributes pipe resonances, those are damped by the tuned Helmholtz absorbers (dampers).
The T140 dimensions are 1140mm/620mm/284mm, 200L (7 cubic feet).
Most would consider that to be a fairly large bass reflex box for a 12" driver.
Kvålsvoll Designs big bass reflex boxes ("compact horns"...) probably don't require unreasonable power, I'd expect from the response of the V-Series the drivers reach Xmax in the 300-400 watt range.
The SA 700 DSP amplifier for "Compact Horn subwoofers" Kvålsvoll Designs offers is rated for 2x 338W / 8 ohm which would be ~52volts..
Art
Attachments
It's an interesting and complex design. Leaves me wondering if there was a simpler way to get a usable response from 20 Hz to 100 Hz without any out of band vent resonances showing up in the response. A Dayton Audio RSS315HFA8 in an 3:1 offset-driver TL (133 L net) or something similar gets close ...
Well it was just meant as a bit of inspiration and food for thought .... ...... got me thinking anyways!
And of course all physics still apply. The pro scene are still using vented enclosures for all the subs .... hard to beat
For the T140, I think it does seem that the "port" does have some progression, thought yes it is could also maybe better be described as a flared transmission line ....
And of course all physics still apply. The pro scene are still using vented enclosures for all the subs .... hard to beat
For the T140, I think it does seem that the "port" does have some progression, thought yes it is could also maybe better be described as a flared transmission line ....
PS. From one of the videos, my best guess is that the 12" woofer used is the B&C 12NBX100, which s also a rather nice woofer with 4" VC .... but not the one you would normally pick for sub