BillFitzmaurice.info

from 45 hz up... 1 to 1 for wide iterations of both. you're always suppossed to use pairs, and I"m sure that vplated 24 inch they will likely match a pair of t60

I thought Id post a graph and the formula to make sure I did it right but I realise the formula goes straight to graph on post, Ill try this

spl width=650&height=250&dbmin=80&dbmax=120&fmin=20&fmax=200]T39W30D3012+9,T60W30DLab12X2+6[/spl

yup it worked, im trying to portray 2 dual loaded T60s and 2 V plated T39's, is this correct?

What you posted is not a fair comparison. The 30" T60 is a dual loaded cabinet, meaning 4 drivers, while the T39s are single loaded.

T60 = 31.25 cubic feet
T39 = 13.20 x 2 = 26.4 cubic feet
For shits and giggles I added the T48 at 36" wide:
T48 = 24 x 2 = 48 cubic feet



This is 2 drivers versus 2 drivers. The titans are not V-plated, add ~+3dB for the v-plate.

Actually I wanted to see the 4 drivers in the T60's vs only 2 T39s V plated. When you mean not fair not fair to the T39's I suppose The 9db increase I added to the T39's was for 2 cabs plus, 6db + 3db for the v plate, is this correct?

Got to read the whole thing first, yup saw the v plate comment

4 drivers each
T60 = 31.25 cubic feet x 2 = 62.5 cuft + 6db
T39 = 13.20 x 4 = 52.8 cubic feet V plated +6+6+3db

I now get the sensitivity vs extension comparison. Is it safe to run the T39's at 45V with a 24db L/R crossover at 40hz. The PA+ only goes to 24db

Excellent tool.

pumpsfast wrote: Is it safe to run the T39's at 45V with a 24db L/R crossover at 40hz. The PA+ only goes to 24db

For four T39's, yes. In fact, as per the plans, you could run them to 50V with your labs.
While some other devices have slopes greater than 24dB, Bill once said, use the steepest slope available. So if that's what you have, that's all good

A couple of people have mentioned that using a steeper slope than 24dB may in fact rob you of some extension and output at 40Hz...

@Grant, thats interesting, maybe its the reason Im so happy with the lows the T39s put out. The 2 rattle the living daylight out of the warehouse. But one day soon Ill build 2 T60 single lab driven cabs and do an ear test myself and see what the whole Tuba vs Titan thing is about. Although it will just be an ear comparison because I know between the 2 styles there cannot be an apples to apples comparison. Dont want to start a war here, or maybe another one.

No war here, pumpsfast. Just wanted to make sure the comparison field was level.

Anybody have a SRX728S Dual 18" High Power Subwoofer Chart,Link http://www.jblpro.com/BackOffice/Produc ... 28S[1].pdf)

read page one man! even a slim 3012lf loaded t39 is close sensitivity wise. the wide one smashes it *IN SENSITIVITY*. keep in mind that a srx728 will likely take upwards of 85 volts or higher, meaning you get more gain on top of this graph, about 30 db at peak (plus some decent distortion volume lol) , where as the t39 will only gain about 26 db at peak. the wide t39 should still keep up with it, and be cleaner though.

Sorry, not in the office, but thanks. Dude is brining the double 18 to do battle tomorrow

sine143 wrote: the wide t39 should still keep up with it,

With both at full power.....nope. Maybe two T39s would get close.

Those 728s at full power (2000 watts) are formidable. And they are heavy, bulky and require a really expensive amp to run 'em.

I'll be running sound on two of 'em tomorrow night (my fourth time with this particular band). And they are only getting half the power that they need. They easily outrun the tops (which are JRX pieces of crap) at only half power.

But, I wouldn't trade my T39s for 'em. All 4 of mine cost less than one 728s. And run on 1/4 the power.

85 volts is 30 db, 50 volts is just shy of 26. speaks for itself right there. If the jbl is percieved as louder its because of the inherent percieved higher volume due to harmonic distortion?

sine143 wrote:85 volts is 30 db, 50 volts is just shy of 26. speaks for itself right there. If the jbl is percieved as louder its because of the inherent percieved higher volume due to harmonic distortion?

Actually 2000 watts at 4 ohms is 89.4 volts. And those boxes can take even more than that.

I can look at charts....but, I use my ears for listening. I don't dispute the charts at all. But, our ears do hear different than a reference mic or modeling software.

I have a decent amount of time in front of 728s in several different venues over the last couple of years .. and of course I've spent some time with my Titans.

I just don't want anyone to think that a single T39 at full power can equal a single 728s at full power. Heck, it shouldn't.....but once again, we're trying to compare these wonderfully designed boxes that we can build in our garage for next to nothing price-wise with tour-level cabinets.

The more realistic comparison is with single 18 boxes that you can buy at GC or MF. That's the world we are in....and we win those wars handily.

i'dprobably pit a pair of t48s at 30" wide vplated against a pair of jbl srx728s full out (based on real world not charts). I've only been to around 14 gigs featuring 728s, powered by big ol macrotechs, (one venue has 2, the other has 4, they use the same model macrotech 5002vz). I'll agree they are loud, right up against em. when the venue fills out you start to wonder a little bit where the sound check volume went. disclaimer, I wasnt at the board, but have been present for plenty of soundchecks. just a listener.