Other popular 18s for tapped horn use at least include the TC sounds 18 LMS ultra, and the Mach 5 UXL, both which clock an EBP in the mid 60s, at anywhere from 3 to 5 times the price of the SI. They are both employed in much lower tuned horns however (but no rear chamber).
Hi sine143,
I understand your motivation but EBP is an indication, not an absolute value. You will need to look at other parameters as well, to get a compete picture.
The lab12 driver is balanced in a very different way. It was designed with the intension to be used in PA basshorns. For instance, it offers a high Qms (stiff-suspension) that is able to cope with the mechanical forces generated by the moving parts. The TH18D2 has a very low Qms (2,88) and lacks such compensation. Also the relation between motor power and moving mass is way better for the Lab12 (1:9,7) compared to the HT18D2 (1: 21,1). If you bring in the Sd (effective cone area) it becomes even worse for the HT18D2.
The lack of motor power and the low Fs of the Lab12 explain its relative low EBP of 56. To overcome this problem the Lab12 was used in a dual driver setting in the Labhorn. More drivers simply mean more motor power.
Tapped horns are something else than ‘conventional’ quarter wavelength basshorns like your FLH suggestion. TH’s allow lower EBP drivers since moving mass is more important than high EBP. Nevertheless, the driver still needs to able to cope with the mechanical forces. The TC Sounds 18LMS is balanced in such way it can handle these forces, also in the long run.
For the HT18D2 it needs testing to see when it runs into severe power compression or mechanical issues.
I understand your motivation but EBP is an indication, not an absolute value. You will need to look at other parameters as well, to get a compete picture.
The lab12 driver is balanced in a very different way. It was designed with the intension to be used in PA basshorns. For instance, it offers a high Qms (stiff-suspension) that is able to cope with the mechanical forces generated by the moving parts. The TH18D2 has a very low Qms (2,88) and lacks such compensation. Also the relation between motor power and moving mass is way better for the Lab12 (1:9,7) compared to the HT18D2 (1: 21,1). If you bring in the Sd (effective cone area) it becomes even worse for the HT18D2.
The lack of motor power and the low Fs of the Lab12 explain its relative low EBP of 56. To overcome this problem the Lab12 was used in a dual driver setting in the Labhorn. More drivers simply mean more motor power.
Tapped horns are something else than ‘conventional’ quarter wavelength basshorns like your FLH suggestion. TH’s allow lower EBP drivers since moving mass is more important than high EBP. Nevertheless, the driver still needs to able to cope with the mechanical forces. The TC Sounds 18LMS is balanced in such way it can handle these forces, also in the long run.
For the HT18D2 it needs testing to see when it runs into severe power compression or mechanical issues.
THanks for the info Djim. I'm always just trying to make this a discussion not an argument. I'm still very new in the world of loudspeaker technology.
the HT18d2 has a qms of 5.8, not 2.88, granted this is still less than half that of the lab12, and still a tad shy of other popular *HT 18s* the LMSU and the UXL (7.5 for the LMSU).
Dont think much further testing will be done on the HT18D2. set to be discontinued
the HT18d2 has a qms of 5.8, not 2.88, granted this is still less than half that of the lab12, and still a tad shy of other popular *HT 18s* the LMSU and the UXL (7.5 for the LMSU).
Dont think much further testing will be done on the HT18D2. set to be discontinued
"SI did mention that this was their production prototype driver and as such it has been beat on and broken in thoroughly so the suspension may be just a hair looser than normal."
Who knows if the current retail version is even the same as the prototype.
Who knows if the current retail version is even the same as the prototype.
Hi sine143,
Chinese manufacturers are also not known for their consistent production lines so indeed, who knows...
Chinese manufacturers are also not known for their consistent production lines so indeed, who knows...
It's a crappy image, but I wanted to get something on here. I'll take a better picture tomorrow.
(I haven't trimmed the edges yet)
(I haven't trimmed the edges yet)
An externally hosted image should be here but it was not working when we last tested it.
Looking good, I hope you are pleased with them 🙂
Thanks to everyone inputting on this thread re: motor force, EBP etc, this place is always an education!
Thanks to everyone inputting on this thread re: motor force, EBP etc, this place is always an education!
Something came up and I wasn't able to get a picture of them. I am back at school now, next time I am home I will be trimming and hopefully painting them.
hahaha will do, there defiantly is enough bass for a small earthquake! I can tell you that much.
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