No, it's 2 pi, though I can't imagine why other than I did it in the wee hours because I couldn't sleep.
Regardless, little wonder it doesn't match up well since Freddy's TH dims are somewhat different than WC's, so try it in his at 2pi and see if we match 'close enough.
Still, yours is a bit different than when I copied the Magnum Pro 12HO into WC's, again at 2pi for consistancy, so where do we diverge?
GM
Regardless, little wonder it doesn't match up well since Freddy's TH dims are somewhat different than WC's, so try it in his at 2pi and see if we match 'close enough.
Still, yours is a bit different than when I copied the Magnum Pro 12HO into WC's, again at 2pi for consistancy, so where do we diverge?
GM
Attachments
Exellent, thanks, looks like the Magnum Pro 12HO works well in that enclosure. As I have 4 of these drivers (and some baltic birch) I think I'll build 1 of the 30Hz TH enclosures first, and see how well it works. Them I may go for some self designed ones after that, so I can compare them.GM said:
William Cowan's 30Hz TH enclosure seem like a nice size also which is alway a bonus. If I get any free time this weekend, I should be able to make some sawdust. 🙂
EDIT: Could you post the parameters of the lower tuned one also? I'm sure I'd run out of xmax below 20Hz, but I wouldn't mind seeing how well it works. 🙂
GM said:
🙂
Someone on a Dutch forum ordered one, just to try it out. He put it in closed and vented boxes and said it works fine, in balance with its price. In addition, its dimensions allow different enclosures than the normal standard squarish boxes, which is the whole point of this driver. I could imagine someone using this driver for a very flat tapped horn, something that sits more flush with a wall than the coffins that you are almost forced to make with regular round drivers.
Like GM said, interesting challenge for DIYers.
GM said:
Good point GM! My initial reaction was the same as Iand's, but I can't fault your logic.
Something like that would be good for a tapped horn in a pickup truck, where the box could be very wide and tall, but shallow enough to fit behind the seats.
Hey, everyone.
A friend and I built a tapped horn today, with a twist -- it's got a constriction at its mouth that mass-loads the horn, gaining a bit of extra extension. That horn is only long enough to support an Fc of 56 Hz, but that's shifted down to 45 Hz by mass-loading. Hornresp predicts a deep (15dB) trough between the two lowermost resonant peaks, but no such behavior was observed -- this thing's small, flat, and loud, if a little resonant-sounding. Driver is the HO version of the 10" Dayton Reference subwoofer. Without realizing what we were doing, we hit levels of 110dB in the driveway -- it's so clean, it didn't even seem loud.
The design needs a bit of tweaking, but here's a photo to tantalize you:
That box is 12"x12"x30" internally, and built from 5/8" plywood, but the baffle and front cover plate are both 3/4".
Measurements will follow soon, once the length of the vent is tweaked.
A friend and I built a tapped horn today, with a twist -- it's got a constriction at its mouth that mass-loads the horn, gaining a bit of extra extension. That horn is only long enough to support an Fc of 56 Hz, but that's shifted down to 45 Hz by mass-loading. Hornresp predicts a deep (15dB) trough between the two lowermost resonant peaks, but no such behavior was observed -- this thing's small, flat, and loud, if a little resonant-sounding. Driver is the HO version of the 10" Dayton Reference subwoofer. Without realizing what we were doing, we hit levels of 110dB in the driveway -- it's so clean, it didn't even seem loud.
The design needs a bit of tweaking, but here's a photo to tantalize you:
An externally hosted image should be here but it was not working when we last tested it.
That box is 12"x12"x30" internally, and built from 5/8" plywood, but the baffle and front cover plate are both 3/4".
Measurements will follow soon, once the length of the vent is tweaked.
Ivo said:
Good to know, thanks! Yeah, I had already done the sims, just hadn't copied/uploaded them when I saw Ian's negative response and posted a 'knee jerk' retort, but you and PB are right, this would make a nice, relatively flat panel speaker or horn for a truck, under a sofa or bed/whatever if the specs are reasonably accurate. Not to mention that due to its layout it may have better distortion specs under load than a typical car audio 'sub' driver.
GM
I was over on Parts Express, looking at car sub drivers to see what might be suitable, and I notice that the specs on car subs tend to be missing parameters.
For example they are running a special on some Lanzar MAX12s at $38.00. It has a couple of things I like, high FS, low Vas, and reasonably high efficiency. However the only specs they list, and I went to the Lanzar site as well are;
*Power handling: 500 watts RMS/1000 watts peak
*VCdia: 2" *Impedance: 4 ohms
*Magnet weight: 130 oz.
*Fs: 35.1
*SPL: 91.9 dB 1W/1m
*Vas: 3.46 cu. ft.
*Qts: 0.57 (Listed as 0.36 on the Lanzar website)
*Xmax: 10mm
I plugged those specs into WinISD Pro and it calculated;
QES: 0.437
QMS: 2.046
I suspect that without at least a few more parameters it would be difficult/impossible to design anything. Is there anything that can be done short of buying one, and testing it?
Paul
For example they are running a special on some Lanzar MAX12s at $38.00. It has a couple of things I like, high FS, low Vas, and reasonably high efficiency. However the only specs they list, and I went to the Lanzar site as well are;
*Power handling: 500 watts RMS/1000 watts peak
*VCdia: 2" *Impedance: 4 ohms
*Magnet weight: 130 oz.
*Fs: 35.1
*SPL: 91.9 dB 1W/1m
*Vas: 3.46 cu. ft.
*Qts: 0.57 (Listed as 0.36 on the Lanzar website)
*Xmax: 10mm
I plugged those specs into WinISD Pro and it calculated;
QES: 0.437
QMS: 2.046
I suspect that without at least a few more parameters it would be difficult/impossible to design anything. Is there anything that can be done short of buying one, and testing it?
Paul
Between the Qts discrepancy and the fact that the SPL spec is probably wrong, ergo the calc'd Qes, Qms ditto, measuring one is by far your best bet unless you use one of their recommended cabs.
GM
GM
GM said:
I didn't mean just vs price, even if the frequency response is flat maximum SPL will be much lower due to comparatively limited power handling and Xmax -- conventional drivers will give a lot higher maximum SPL in the same size box.
Since extended response and high maximum SPL are generally the whole point of tapped horns, this kind of goes against this 🙂
Ian
Understood and a valid argument for a prosound forum where SPL reigns supreme, but not so much for a car audio, HIFI and/or HT app DIY one.
GM
GM
Using GM's x-max and pwr for MTX
adding the 300watts needed to max out the driver only nets an additional 3db increase. So raise the spl chart up by 3db to see the added spl.
GM said:
adding the 300watts needed to max out the driver only nets an additional 3db increase. So raise the spl chart up by 3db to see the added spl.
wow
133db at 15hz or so isn't too shabby... I think i found my new HT subwoofer...
In your pdf you said "but it increased the TH some."
did you mean that it increased the size a little bit or it increased the total harmonic (distortion)?
133db at 15hz or so isn't too shabby... I think i found my new HT subwoofer...
In your pdf you said "but it increased the TH some."
did you mean that it increased the size a little bit or it increased the total harmonic (distortion)?
Does reversing the driver make much difference? I've found the my Magnum 12HO is too deep to mount in Cowan's 30Hz enclosure the same way as the peerless, so would mounting it backwards affect things at all?