Introducing SPL Chart

Anything not covered elsewhere.
Message
Author
sine143
Posts: 3066
Joined: Sat Feb 06, 2010 3:27 pm
Location: Raleigh NC

Re: Introducing SPL Chart

#256 Post by sine143 »

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

Built:
2x Tuba 30s delta12lf loaded (gone)
4x Otop12 d2512 loaded
8x t48s (18, 18, 24, 24, 30, 30) 3015lf loaded
2x AT (1 mcm, 1 gto 804)
2x SLA Pro (dayton pa6, 6 goldwood piezo loaded)
1x bastard XF208

2x OT212 (delta pro 450a loaded, eminence psd)

Michael Murphy
Posts: 343
Joined: Sun Dec 30, 2012 2:17 pm
Location: Trinidad

Re: Introducing SPL Chart

#257 Post by Michael Murphy »



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?

User avatar
DJPhatman
Posts: 5412
Joined: Mon Aug 14, 2006 5:08 am
Location: Warren, MI
Contact:

Re: Introducing SPL Chart

#258 Post by DJPhatman »

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.
I know money often seals the deal, but seriously, quality is an investment, not an expense... Grant Bunter
Accept the fact that airtight and well-braced are more important than pretty on the inside. Bill Fitzmaurice

Michael Murphy
Posts: 343
Joined: Sun Dec 30, 2012 2:17 pm
Location: Trinidad

Re: Introducing SPL Chart

#259 Post by Michael Murphy »

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 :oops:

Michael Murphy
Posts: 343
Joined: Sun Dec 30, 2012 2:17 pm
Location: Trinidad

Re: Introducing SPL Chart

#260 Post by Michael Murphy »



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.

Grant Bunter
Posts: 6915
Joined: Mon Nov 28, 2011 11:12 am
Location: Ilfracombe Queensland Australia
Contact:

Re: Introducing SPL Chart

#261 Post by Grant Bunter »

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...
Built:
DR 250: x 2 melded array, 2x CD horn, March 2012 plans.
T39's: 4 x 20" KL3010LF , 2 x 28" 3012LF.
WH8: x 6 with melded array wired series/parallel.
Bunter's Audio and Lighting "like"s would be most appreciated...

Michael Murphy
Posts: 343
Joined: Sun Dec 30, 2012 2:17 pm
Location: Trinidad

Re: Introducing SPL Chart

#262 Post by Michael Murphy »

@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. :fruit:

User avatar
DJPhatman
Posts: 5412
Joined: Mon Aug 14, 2006 5:08 am
Location: Warren, MI
Contact:

Re: Introducing SPL Chart

#263 Post by DJPhatman »

No war here, pumpsfast. Just wanted to make sure the comparison field was level.
I know money often seals the deal, but seriously, quality is an investment, not an expense... Grant Bunter
Accept the fact that airtight and well-braced are more important than pretty on the inside. Bill Fitzmaurice

Michael Murphy
Posts: 343
Joined: Sun Dec 30, 2012 2:17 pm
Location: Trinidad

Re: Introducing SPL Chart

#264 Post by Michael Murphy »

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

sine143
Posts: 3066
Joined: Sat Feb 06, 2010 3:27 pm
Location: Raleigh NC

Re: Introducing SPL Chart

#265 Post by sine143 »

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.

Built:
2x Tuba 30s delta12lf loaded (gone)
4x Otop12 d2512 loaded
8x t48s (18, 18, 24, 24, 30, 30) 3015lf loaded
2x AT (1 mcm, 1 gto 804)
2x SLA Pro (dayton pa6, 6 goldwood piezo loaded)
1x bastard XF208

2x OT212 (delta pro 450a loaded, eminence psd)

Michael Murphy
Posts: 343
Joined: Sun Dec 30, 2012 2:17 pm
Location: Trinidad

Re: Introducing SPL Chart

#266 Post by Michael Murphy »

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

Bruce Weldy
Posts: 8301
Joined: Fri Nov 27, 2009 11:37 am
Location: New Braunfels, TX

Re: Introducing SPL Chart

#267 Post by Bruce Weldy »

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.

6 - T39 3012LF
4 - OT12 2512
1 - T24
1 - SLA Pro
2 - XF210


"A system with a few knobs set up by someone who knows what they are doing is always better than one with a lot of knobs set up by someone who doesn't."

sine143
Posts: 3066
Joined: Sat Feb 06, 2010 3:27 pm
Location: Raleigh NC

Re: Introducing SPL Chart

#268 Post by sine143 »

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?
Built:
2x Tuba 30s delta12lf loaded (gone)
4x Otop12 d2512 loaded
8x t48s (18, 18, 24, 24, 30, 30) 3015lf loaded
2x AT (1 mcm, 1 gto 804)
2x SLA Pro (dayton pa6, 6 goldwood piezo loaded)
1x bastard XF208

2x OT212 (delta pro 450a loaded, eminence psd)

Bruce Weldy
Posts: 8301
Joined: Fri Nov 27, 2009 11:37 am
Location: New Braunfels, TX

Re: Introducing SPL Chart

#269 Post by Bruce Weldy »

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.

6 - T39 3012LF
4 - OT12 2512
1 - T24
1 - SLA Pro
2 - XF210


"A system with a few knobs set up by someone who knows what they are doing is always better than one with a lot of knobs set up by someone who doesn't."

sine143
Posts: 3066
Joined: Sat Feb 06, 2010 3:27 pm
Location: Raleigh NC

Re: Introducing SPL Chart

#270 Post by sine143 »

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.
Built:
2x Tuba 30s delta12lf loaded (gone)
4x Otop12 d2512 loaded
8x t48s (18, 18, 24, 24, 30, 30) 3015lf loaded
2x AT (1 mcm, 1 gto 804)
2x SLA Pro (dayton pa6, 6 goldwood piezo loaded)
1x bastard XF208

2x OT212 (delta pro 450a loaded, eminence psd)

Post Reply