39Hz is surprisingly deep. The wide non beaming sound is a signature of the K aperture. Glad it's working out nicely.
I know, it sounds unbelievable. I just tried generating tones in Audacity to confirm and same result. I must get a proper mic. By ear, shoulder is around 40 Hz with rapid fall from 38 Hz.
Hi Sredni,
I'm very grateful for your time and trouble doing that. to be honest I don't understand the graphs. If basically a FR graph I can see a higher spl in th bass at the expense of about 3 Hz in F3. Is that right? The rest of the graph looks terrible but I'm sure the speakers don't sound nearly that bad 🙂. The carpet felt has arrived and I'll remove the vertical section of the duct in a few days when I get home.
Again thanks.
I'm very grateful for your time and trouble doing that. to be honest I don't understand the graphs. If basically a FR graph I can see a higher spl in th bass at the expense of about 3 Hz in F3. Is that right? The rest of the graph looks terrible but I'm sure the speakers don't sound nearly that bad 🙂. The carpet felt has arrived and I'll remove the vertical section of the duct in a few days when I get home.
Again thanks.
drewan, yes you lose some extention to get a flatter response with higher SPL. I have found that adding the Karlson aperture lowers the tunng by 4-5 Hz compared to the simulation, I guess because it increases the effective length of the duct. According to xrk971, the Akabak simulation does not model the high frequencies well, so you can ignore that part of the plot.
xrk971's XKi exercise is a simplified bandpass box approximation to examine how the lower end should respond. His original Karlson and GregB's Karsonator Akabak scripts are much more complex.
One of these days I should modify the K15 script to be an XKi that accounts for the higher frequencies better. But for now it's not a bad way to size a box for the bass component.
you should be able to rear mount PA130 with no trouble as long as the cutout clears the surround
would a single or double PYM1298 XKi be a potent project? PYM1298 was Pyle's Eminence built 12 that was much like the modern Kappa12a
it doesn't go real low in a factory K12 but is punchy and the 3 inch coil pretty tough
Def_Driver 'Pyle PYM1298' |Notes: Pyle Eminence 12" driver 97.8dB 1W/1M 3.2mm XMax 600 watts
SD=509.9cm2
fs=44.2Hz
Mms=43.1
Qms=6.76
Qes=0.31
Re=5.16
BL=14.15Tm
Le=0.54mH
Vas=111.2L
it doesn't go real low in a factory K12 but is punchy and the 3 inch coil pretty tough
Def_Driver 'Pyle PYM1298' |Notes: Pyle Eminence 12" driver 97.8dB 1W/1M 3.2mm XMax 600 watts
SD=509.9cm2
fs=44.2Hz
Mms=43.1
Qms=6.76
Qes=0.31
Re=5.16
BL=14.15Tm
Le=0.54mH
Vas=111.2L
FWIW, I have a pair of these PYMs and can volunteer to build a double if the sims are favorable enough (ie. it goes low enough to be a passable sub). In my slit vent K12, they were "Ok" - punchy but didn't dig low enough.
I can have a go at the sim. The cabinet will be pretty big though. I am guessing the rear chamber will be over 100 L, and with the front chamber, cabinet volume will be 125L+. So 14" x 14" x 38" - maybe a bit more.
that's not much different than a single 12" Karlsonator - I know its work to simulate but might be interesting to see what a single and double would do. Would f3 for the 125 liter double case be ~60Hz? Would 2.83v sensitivity for the double woofer box be above 100dB? There's not a lot of xmax but think its pretty linear within that figure. I get about an 80Hz corner with one pym1298 in a regular K12 tuned in the low 60s. A K-tube on top with compression driver will easily match one pym1298/kappa12a
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for a single driver XKi as a more worthy contender, I've a beefy 12" coax with 109 ounce magnet, 4" coil and 4.8mm of coil overhang - - its been run briefly in a vintage Karlson K12 and had a very nice midrange on classical material such as Fritz Wunderlich singing lieder
subjectively its not as sensitive as my Martinprosound 80oz magnet custom Eminence coax
Def_Driver TSG big 12cx |Notes: TSG 12-1844 Eminence 12CX 109oz magnet - Qts 0.27 -4.8mm overhang 4" coil - 2x5" HF horn
SD = 532.36 Cm2
Fs = 44.41 Hz
Mms = 57.4 g
Qms = 9.95
Qes = .27
Re = 5.52 ohms
BL = 17.96 Tm
Le = 1.68 mH
Vas = 86.6L
subjectively its not as sensitive as my Martinprosound 80oz magnet custom Eminence coax
Def_Driver TSG big 12cx |Notes: TSG 12-1844 Eminence 12CX 109oz magnet - Qts 0.27 -4.8mm overhang 4" coil - 2x5" HF horn
SD = 532.36 Cm2
Fs = 44.41 Hz
Mms = 57.4 g
Qms = 9.95
Qes = .27
Re = 5.52 ohms
BL = 17.96 Tm
Le = 1.68 mH
Vas = 86.6L
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For the double I had a quick go in Akabak. With 100 L rear chamber and 25 L front, 37cm wide internal cabinet, duct 5cm high by 11cm long it is over 100 db. (note duct will be a a bit shorter - have not included end effect at rear of duct). Apologies for metric but a pain to convert sim to imperial.
An externally hosted image should be here but it was not working when we last tested it.
(working on the single etc.)
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thank you very much for that double pym1298 XKi simulation - its not shabby at all and very good extension - the only concern is whether the peak just below 200Hz will be that intense - an extra resonator above the duct might (?) tame that tendency and is in MMJ's "Karlflex" model
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yeah - w. offset driver feature - I'd like to keep the K-aperture, MMJ stopped short as felt it was better with his Dayton PA310 12" woofer without a lens/cavity - there was very little depth in his front chamber so maybe that's why the aperture wasn't desirable
MMJ's Karlflex prototype appears around 4:10 in this video with a step-up transformer driven ksn1016 knockoff Frankenpiezo made of GRS and Goldwood parts https://www.youtube.com/watch?v=krvtPAdgVnw
MMJ's Karlflex prototype appears around 4:10 in this video with a step-up transformer driven ksn1016 knockoff Frankenpiezo made of GRS and Goldwood parts https://www.youtube.com/watch?v=krvtPAdgVnw
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