TH-18 Flat to 35hz! (Xoc1's design)

Djim that comparison isn't really fair showing the difference between the two. What I mean is, at 1w input they seem very close. When in reality the ss15 runs out of steam wayyy before the TH-18 does. Xmax is exceeded with around 56 volts if I remember correctly on the ss15, and on the TH-18 it is nearly double that.
 
Djim that comparison isn't really fair showing the difference between the two. What I mean is, at 1w input they seem very close. When in reality the ss15 runs out of steam wayyy before the TH-18 does. Xmax is exceeded with around 56 volts if I remember correctly on the ss15, and on the TH-18 it is nearly double that.
2,83V isn't the same as 1watt, and yes the SS15 loaded with 3015lf will be run out even before the continue power of the TH18 loaded with 18Sound. The only reason I made the comparison was to show they can go together without issues.

4 x SS15 loaded with RCF L15P200AK's (8ohm versions) + 2 x TH18 loaded with 18Sound 18LW2400 (4Ohm version) gives all kinds of options from small to medium gigs. You can even run them from one 2 x 4000 watt (2Ohm) amp if necessary.

Or if you don't need the SPL you can run them all from a 2 x 2000W (2Ohm) amp that is also able to power 2 x 1600 (4Ohm) for two TH18's or four SS15's and even 2 x 1000 (8Ohm) for two SS15's. After a while you can expand with a second amp (if needed). That way you can create a versatile setup with lots of possibilities.
 
Last edited:
would a peavey lowrider or one of the eminence 18" drivers work in this cabinet. i was getting ready to cut 2 of jbell's SS15, but i saw this thread. i am just looking for a cabinet to use for live band application only. so i will never need anything below say 45hz.
For 225$ you can have the P.Audio C18-650EL. It has double spider, demodulation ring, high headroom (AES 1200Watt - 2400W max), high quality build with tight tolerances and sims good in the Xoc1-TH18.

Xoc1_TH18-2_Paudio_C18-650EL.jpg
 
Great thread, I really like the folding stuff in CAD, that seems to offer better precision and tweakability compared to doing it on paper.

I wonder if the Void V18-1000 driver would work well in this enclosure?

It's priced around the same as the 18LW2400 (in the UK at least), offers higher Xmax, had a larger voice coil and also has a higher BL value so is probably another driver to consider if you can get hold of it that is. :)
 
Ok, I think I managed to piece together enough data to run a few sims now:

An externally hosted image should be here but it was not working when we last tested it.

The black line is the 18LW2400
The grey line is the V18-1000

The Void driver does pretty well I think, I've tried to use the similar settings to the picture in the first post, SPL is at Xmax+1.6mm using 4 speakers. :) I'd love to hear 4 of these in full effect with a decent amp... :D
 
Last edited:
Looks like a winner, how much drive voltage to get there?
100v, which works out to be a little over the 1000Wrms rating for the driver, so I'm not really sure if you could get away with putting that much power thru the driver for hours on end.

If I reduce the drive voltage to 89.44v to match the 1000W power rating, the V18-1000 still has the edge and it's only just exceeding it's Xmax:
An externally hosted image should be here but it was not working when we last tested it.


I updated the pic in my past post with the 89.44v plot for the V18-1000
An externally hosted image should be here but it was not working when we last tested it.

Black plot = V18-1000 with 100V drive voltage (1250W)
Grey plot = V18-1000 with 89.44V drive voltage (1000W)
Red Plot = 18LW2400 with 70v drive voltage (612.5W)

EDIT: I've heard some people mention that the V18-1000 and PD.1850 are very similar or even the same driver - the specs are pretty similar at least. You may find the PD.1850 a little easier to find if you cannot find anywhere locally that sells the V18-1000...

The PD1850 datasheet claims "Power compression only 1.6dB at rated power" which seems pretty good to me, it's a shame more manufacturers don't try and measure power compression...
 
Last edited:
I've heard some people mention that the V18-1000 and PD.1850 are very similar or even the same driver - the specs are pretty similar at least. You may find the PD.1850 a little easier to find if you cannot find anywhere locally that sells the V18-1000...

The PD1850 datasheet claims "Power compression only 1.6dB at rated power" which seems pretty good to me, it's a shame more manufacturers don't try and measure power compression...
That is indeed an extreme low power compression figure. If I'm correct the factory specs even suggests 1.6dB at 1600 watt.

If I calculate the power compression at calculated Xmax for the PD1850 loaded in the Xoc1-TH18 I’ll get:

Calculated Xmax = 8mm

BL/Mms ratio = 1: 6.85 (this looks promising)

800W and an Re of 5.37Ohm = 65.54V (9.0359mm excursion @ 46Hz)

58.09V and Re of 5.37Ohm 628.39W (8mm excursion @ 46Hz)

800 : 628.39 = 1.273

Factor 1.273 stands for 1.05dB at 800Watt (AES power rating)

That is an impressive low pwr compr. figure...
 
Last edited: