Back in 1982, when Public Enemy started to become popular, 200 Hz was a common crossover point between lower and upper drivers in professional high-output live sound use, before the term "subwoofer" became popular in consumer products.
The term "subwoofer" is derived from the prefix "sub" meaning “underneath or lower”, and has been used in that context since the 1970s, long before wiki existed.
That said, Camplo's use of a high frequency compression driver for frequencies down to ~200Hz does not fit any typical product range..
Last edited:
Back in the early 80’s (and before) 200 Hz was a practical lower limit for a horn loaded 10 or 12” MIDRANGE. If you want it efficient, as in 105 dB/W it’s got to be 1/4 wave loaded. A practical straight horn (with a full or half size mouth) will get you down to 200 - maybe 150 if you’re willing to deal with 6+ cubic foot mids. Boxes that were often flown or stacked. EQing an EVM10L on an 18” long horn down to 80 would run you out of excursion (and amplifier power) quick, so that wasn’t an option. So naturally the bass bins would be expected to go up high enough. They weren’t expected to go below 40 (or even 50 to 60) either.
Facts.
Car Audio SQ guys would use 200-250hz low pass filters if the subwoofer was mounted in the footwell or dash of a car.
Most of them would use 50-60hz low pass filters if the subwoofer was in the trunk for that "upfront bass."
Exactly, NOT 20hz SUBwoofers playing to 200hz.
2 octaves are the norm.
20-80hz SUBwoofer.
50-200hz Bass Bin.
Those were reflex boxes, not horns, right? A lot easier to get a clean 30-200 Hz. And they wanted power handling out of the 10’s - and I’m guessing they were high efficiency in the high 90’s to low 100’s with 3 mm of x-max to keep up with the 18’s, not just over 90 dB/W with 10+ mm.
Hell, all these miniature 15” tapped horn designs floating around here won’t even get you those two octaves.
It all sh!ts the bed after 3x the 1/4 wavelength Unless you move the driver down 1/3 closer or extend the resonator length on the opposite side by 1/3(bose wave cannon/paraflex)?
Is there a way to shrink the qw resonators down in length to extend the HF cancelation above 6 x the 1/4(Fb) freq?
much like the OD position brings the driver output/vent closer together, the parallel resonators push them further apart (out of phase at 4/4, 8/4,12/4 etc …. Extended to the 6/4, 10/4…wavelenths .?)
also, roll off on the bottom end starts so above Fb…. 🥲
Last edited:
My subwoofer currently Plays 20hz-200hz. Its been a while but I think I tested it with tones once upon a time but I don't remember the results. Dual 18's 14mm xmax, very low Le, in a ~320 liter box. I do remember testing it with music that had a deep bass note at ~30hz with a vocal lower note at ~200hz. I turned it up very loud and listened for the vocal to distort.... It did not. I'm not sure of SQ at the 200hz crossband vs some type of Cinematic explosion with content down to 20hz or lower... but with the subs in Stereo totalling to 4 18"s I am not worried.
I don't know why I keep researching vented enclosures, It seems only an offset BR has a good enough FR to make it up to a 200hz xo. @Booger weldz if you stuff a tapped horn it seems to work out but what I find intriguing about the BR I posted is the undampened smooth response, basically all that efficiency... I don't need it, per say, I just want for some reason lol
I figured I'd start this thread to see if anything interesting comes a long and to help designers resource solutions for this unique design issue. This type of driver/enslcosure set up is usefull in my opinion, in a design that is a two or 3 way where one is able to cross to such a sub, and then eliminate an additional design to cover sub. Vertically stacked 18's can make it up higher than a 200hz xo, I mean the 4277n is corosed at 600hz. Its just a matter of getting the right drivers and the right amount of drivers etc. The jbl is tuned to 34hz?? but in pairs in a domestic situation it might make it to 20hz? @mitchba might know.
But yeah, its a unique design ask to completely reach 20hz while crossing high but when it works, you eliminate a crossover
I don't know why I keep researching vented enclosures, It seems only an offset BR has a good enough FR to make it up to a 200hz xo. @Booger weldz if you stuff a tapped horn it seems to work out but what I find intriguing about the BR I posted is the undampened smooth response, basically all that efficiency... I don't need it, per say, I just want for some reason lol
I figured I'd start this thread to see if anything interesting comes a long and to help designers resource solutions for this unique design issue. This type of driver/enslcosure set up is usefull in my opinion, in a design that is a two or 3 way where one is able to cross to such a sub, and then eliminate an additional design to cover sub. Vertically stacked 18's can make it up higher than a 200hz xo, I mean the 4277n is corosed at 600hz. Its just a matter of getting the right drivers and the right amount of drivers etc. The jbl is tuned to 34hz?? but in pairs in a domestic situation it might make it to 20hz? @mitchba might know.
But yeah, its a unique design ask to completely reach 20hz while crossing high but when it works, you eliminate a crossover
Last edited:
And by eliminating the crossover, either the high output low frequency or bass in the ~100-200Hz range is generally compromised.
That said, my old quad 15" L4 design worked very well with a 200Hz crossover:
I don't have any surviving measurements, but the Hornresp sim is not far off, using the EVX150 at 6.4mm Xmax.
Current woofers could exceed this level by 6-10dB, though may not sound as good in the upper range:
With a bit of EQ, ~35 Hz response still sounded decent.
Lowering the Fb to 30 Hz or 20Hz, the L4 with the EVX150 could still make things happen, but not much thump by comparison, and the 20Hz tuning uses less voltage to reach full excursion.
The long 20 Hz ports have a resonance in the 120Hz range, not good, but still above 115 dB with no room gain with a modest 36 volts. The old Crest amps we used had no problem with the impedance minima of only 1.3 ohms with the Beastie Boys, Nine Inch Nails or Prince.
We were using Brooke-Siren FDS-340 crossovers which had a fixed 20Hz HP filter, almost an octave below the 38Hz Fb...
Using two modern 18" drivers, Mark100's "VTwin" looks like it could easily be tuned down a bit to 20Hz and would kill the L4 in output:
That said, don't know if it's 200Hz range would still sound good modulated by over 15mm excursion.
Art
I know this is a completely different approach/ philosophy, but why not do a 2 in 1 subwoofer? Make something like Genelec does with the W371A or 8381A? I think this will give the range you want, in a smaller package, and optimize detail and clarity
That's what I did. In my design I combined Lab 12's (sealed) and 12" Dayton Ultimax (ported). I have cabinets with 2 subs each, and with some careful equilization I can get a nearly flat frequency response from 20-100hz, similar to common multiple subwoofer methods.
Here are raw measurements of the 2 separate drivers from one of my speakers. The ported sub is ~100 liters and low passed at 100hz, and the sealed sub is ~30 liters (1 cubic foot) and low passed at 250hz. (No smoothing):
Here is the combined result of 2 pairs of these 2 in 1 subs with some DSP. (No smoothing.):
Genelec's W371A uses the sealed + ported approach, and the 8381 uses dual opposed drivers for the low frequencies. So I suppose there are lots of solutions.
I was looking at the Bill Fitzmaurice cabinet plans to see how wack his subs got and that appears to be this one. It's a 2x12", measures 60"x30"x30", and is designed so that if you want to bring down the footprint you can lose one of the 12"s and build it as 60"x30"x15". Purports to be about -16.5dB down at 30. There's also a 1x15" option.