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Discussion Starter #1
I have a wallet-affecting quandary for you guys:

I’m pondering my new sub configuration in a new vehicle, and I’m looking to “get it right” (get what I expect from my system) the first time. This is for a 2013 Toyota 4Runner SUV. The box will be rear firing and rear-ported. I’m looking for a very robust SQL setup that reaches fairly low (upper 20Hz range with some authority) and will cleanly hit in the mid-to-upper 140dBSPL’s or so w/o undue sub stress.

I already have (4) of the W12GTi’s (one spare) ready to go, but I’m re-considering my choice – mainly due to the size of the box required for three ported 12”s.

I recently ran a pair of the W12GTi’s in a ~2.1 cu.ft. per chamber sealed box in my ’99 Tacoma Xtra Cab on a Rockford 1500-1bdcp. I was happy with them, but desired a bit more clean SPL – especially below 40Hz. I’m anticipating the Ported Box and different cabin gain in the 4Runner will be a nice boost over the old Tacoma system, plus the 3rd 12” and additional amplifier power (ARC KS2500.1) should get me where I want to be (I think).

Since the new 4Runner has ample room, I will be building rear-facing/rear-ported boxes for either configuration (3x 12”s, or 2x 13”s). The W12GTi needs about the same size box as the 13W7 (approx. 2.25-2.35 cu.ft. / 28-30Hz port) – but I’d obviously have an extra W12GTi making their box ~50% larger (and heavier) overall.

It’s not that I’m totally against a larger/heavier box, but if the pair of 13W7’s will surpass the trio of W12GTi’s and do it with a 33% smaller box then sign me up! :) I can re-sell my W12GTi’s (two are still BNIB) and recoup most of the price difference. I'd still lean towards the W7's even if it's pretty close overall due to size and weight.

I already purchased the ARC KS2500.1 to drive the subs (just came in today - does 2848Watts @ 1 Ohm!!!). The pair of 13W7’s will be a net 1.5 Ohm Load and get a little less power than a trio of W12GTi’s at 1 Ohm - AND the JBL's are quite a bit more efficient than the W7's to begin with. (11/09/12 EDIT - Please see my "Adjusted" W12GTi sensitivity of around 86.5dB @ 1W specs towards the bottom of this thread - the GTi and W7 are actually roughly equal in efficiency @ 1W!). I’m figuring approx. 900-1000 Watts per 13W7 – is that sufficient for my above expectations? Will the W12GTi's higher sensitivity (and higher overall amplifier power @ 1 Ohm) reign supreme over the W7's in this scenario?

Thanks for any input before I decide to throw-down on a pair of 13W7AE’s! I’m teetering on the “Finalize Your Order” button as I type!!! :deal2:
 

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Discussion Starter #2
Friday Bump: Which will have more output on a ARC KS2500.1?:

(2x) 13W7's with approx 950 Watts each in a 2.4 cu.ft. (per driver) box ported @ ~30Hz

(3x) W12GTi's with approx 950 Watts each in a 2.25 cu.ft. (per driver) box ported @ ~30 Hz?

I've never had any experience with the W7's, but I know the W12GTi's well (but only in sealed boxes).

I'd prefer the smaller box for the (2) 13W7's, but the JBL's are a good deal more efficient - and I already have them. Thoughts? :cool:
 

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i say build a box for what you already have. see if that's the sound your lookin for. then after that if you decide you want more hold off till tax season and sell me 2 of the wgti's and then buy ur w7 :D
 

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Discussion Starter #4
:D

That's part of my quandary! I'm looking to do this (at least the sub configuration and box) once and be done.

It seems like the 13W7's are tough to beat for overall SPL output since they have so much Xmax and cone area - and the small box requirements are also a plus! But, the W12GTi's are quite a bit more sensitive, but would obviously require a larger box (since there's three of them). The 3x JBL's will also get the full potential from the amp @ 1 Ohm Mono.

I'm really curious if the additional sensitivity and additional amplifier power available with the JBL setup has any chance of surpassing the 13W7's in raw output.

Considering all of this, which setup would have more overall SPL? If the pair of 13W7's can easily match (or surpass) the trio of W12GTi's in my proposed configurations, then I think I'd prefer to go the W7 route for the space-savings.

This is obviously not a cheap decision ($1500 in woofers!!!) - and I want to get it right from the start - so I'm relying on the board's experience to help me decide JBL or JL :) (See post #1 for additional info)

Thanks so much!!!!!!!!!!!!!! :cool:
 

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Discussion Starter #6
I've never trusted going strictly by the numbers when so many other variables are at play (T/S variations/deviations, cabin gain and loading, how it actually sounds, etc) - but this is a good way to get a general ball-park.

I don't have any first-hand experience with the W7's, and some claim they can "Drone" - I assume this is due to their higher-Q small-box recommendations? Or possibly just due to poor integration and improper system tuning?

I'll plug in some numbers and play around - but I'd like some "in the field" confirmations as $1500 is a lot to base off some (possibly inaccurate/fudged) T/S numbers ;) I've been really happy with the JBL's in my old Tacoma, but again space savings is always nice (especially if it also means MORE SPL/SQL! :) )...

On a side note - How much trust can one have in published sensitivity ratings for a sub? 13W7 says [email protected]@1M and W12GTi says [email protected]@1M (and the W7's "1W" is probably 2.83v @ 3 Ohms, or 2.66Watts) . From my experience, the SPL actually produced in the 20-80Hz range doesn't always correlate to the published sensitivities...
 

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:D

That's part of my quandary! I'm looking to do this (at least the sub configuration and box) once and be done.



This is obviously not a cheap decision ($1500 in woofers!!!) - and I want to get it right from the start - so I'm relying on the board's experience to help me decide JBL or JL :) (See post #1 for additional info)

Thanks so much!!!!!!!!!!!!!! :cool:
How is going with the JBLs first going to cost you anything? You mentioned you already have the JBLs so the cost would be just the cost of making the box. Are you building it yourself or having someone build it for you? Since there are so many variables and unknowns, I would say to go with what you already have and if you don't like it, you can sell it and get the JLs. If you get rid of the JBLs now and don't like the JLs, what will you do? Buy the JBLs again?
 

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Discussion Starter #8
I'm looking to avoid building two boxes (and then two amp racks). The cost of the materials and coverings are not my main concern, but the time involved. I tend to take my sweet time, and swapping from one to the other will be a slow process with my extremely busy work schedule (includes taking vacation time, etc)...

Two of my W12GTi's are BNIB - so if I do install them and decide to swap to W7's, I can expect to lose some re-sale value, too.

If I do end up purchasing 13W7's and trying them first, I'll hang onto the W12GTi's until I'm sure the W7 system meets my expectations. Then, I'll either sell the GTi's, or use them in my HT system (would prefer 2241G 18"s for that!).

I'm really liking the idea of a smaller box with (possibly) MORE output from the W7's. That is the driving factor for me at the moment. My old 1987 4Runner had two "OG" Punch Pro Series 18"s that took up the entire cargo area, and I really think this "modern" system can beat it in 1/4 the space! :D
 

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Discussion Starter #9
FWIW - WinISD is supposedly saying the JBL's will be 6-7dB Louder @ 30Hz - and somehow I just don't believe that. WinISD's port dimensions seem to be way off, too.

I've used Boxplot for basic box design and port dimensions (a step-up from using the "RTTI Port Tuning Nomogram" from the 80's/90's - talk about old-school!), but it won't run on W7-64 (and even had issues with BoxPlot in an XP Virtual Machine, too!!!). I'll see what else I can use to plug in some numbers, but it seems the JBL's will always measure much louder on paper due to the skewed sensitivity ratings when I know others out there have much different real-world experience...

Any suggestions on an accurate way to model these two setups that will reflect a real-world result?

Thanks! :cool:
 

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I dont see what more info you need, if it says its louder, then it will be louder. If you liked the sound of the Gti's before, just wanted some more output, then the 3rd one will give you that and not cost you anymore money since you already own it. Its a no-brainer IMO, spend the money the JL's would cost for your home subs you want.
 

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Discussion Starter #11
Yeah - I'm just back-pedaling on the size of the box that will be needed for 3x ported 12"s. I guess the W12GTi's do end up with a slightly larger piston area (0.144 sq.m. vs 0.138 sq.m. for the W7) - but the W7's have about 9mm more Xmax.

I was honestly thinking the two 13W7's would have more surface area - guess I was wrong!!!

Well - I'll have to ponder this over. A smaller box is certainly appealing, but only if total output remains the same or higher...

Thanks for knocking some sense into me :laugh: 3x 12"s is still pretty small compared to the snug-top/cut-through 8x 18"s in my first Mazda B2200 Pickup! :eek:
 

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Yeah - I'm just back-pedaling on the size of the box that will be needed for 3x ported 12"s. I guess the W12GTi's do end up with a slightly larger piston area (0.144 sq.m. vs 0.138 sq.m. for the W7) - but the W7's have about 9mm more Xmax.

I was honestly thinking the two 13W7's would have more surface area - guess I was wrong!!!

Well - I'll have to ponder this over. A smaller box is certainly appealing, but only if total output remains the same or higher...

Thanks for knocking some sense into me :laugh: 3x 12"s is still pretty small compared to the snug-top/cut-through 8x 18"s in my first Mazda B2200 Pickup! :eek:
I think your piston area calculations are off. The 13 should have the area of a 15.
 

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Discussion Starter #15
Yep ;)

I'm still pondering which way to go. A smaller box is very appealing to me, and I still doubt the W12GTi's would have a 6-7dB advantage over the 13W7's (according to WinISD). Decisions, decisions. I can wait another few weeks before I start building the box - so I still have a little time to figure it all out.

I'd love to hear from those that have run both woofers as I was under the impression the W7 will spank the GTi in "real world" SPL/SQL (plus must take into account the small surface area deviation between the two setups)....

:cool:
 

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Discussion Starter #16
OK - So I "corrected" the WinISD W12GTi sensitivity rating of 91dB @ 2.83v to mean approx 87dB @ 1 Watt (1W at 3 Ohms with the coils in parallel). This "correction" is only valid if the JL's are actually rated @ 1W/1M - and 1W being referred to at 3 Ohms (not blindly calling 1W as "2.83v" like some manufacturer's might).

If that IS the case, the JBL's and JL's are actually pretty close in sensitivity...

I plugged in (3) W12GTi's vs (3) 12W7's (apples to apples with 2848 watts in the same box), and the W12GTi's still edge out the 12W7's around the tuning frequency???

I swear I've read tons of threads where people claim the W7 of same diameter will be louder with similar power (~950 Watts per) due in part to the larger surface area and increased Xmax.

Green. .= 3x W12GTi / 2848 Watts with 91dB @ 2.83v Sensitivity entered
Orange = 3x W12GTi / 2848 Watts with 87dB "Adjusted" Sensitivity entered
Yellow .= 3x 12W7 / 2848 Watts with 86.2dB sensitivity entered
Red . . .= 2x 13W7 / 2000 Watts (@ 1.5 Ohms) with 86.3dB sensitivity entered




Does that jive with what people actually experience "in the wild"?

PS - WinISD's Port Calculations seem to be fine - they were defaulting to "Meters" - and showed "0.0" length at first. I just figured out you can click on the unit of measure and flip through many different units! Pretty cool for a program that's over a decade old IMO...
 

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The extra Xmax of the jl means little unless you are hitting the Xmax limits of the jbl subs on the given power. I would choose the jbl subs because you have them, 3 motors are going to suffer less power compression than 2 motors and 3 twelves are about the same cone area as 2 fifteens. Usually just slightly under. More cone area usually means louder on the same power.

What are you planning on tuning at?
You modeled them under power to see Xmax and port velocity?
You played with enclosure size to see if you could get away with a smaller enclosure for the jbl's?
 

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Discussion Starter #18
The extra Xmax of the jl means little unless you are hitting the Xmax limits of the jbl subs on the given power. I would choose the jbl subs because you have them, 3 motors are going to suffer less power compression than 2 motors and 3 twelves are about the same cone area as 2 fifteens. Usually just slightly under. More cone area usually means louder on the same power.
Agreed - I'd also prefer spreading the power across 3 drivers for reliability...

What are you planning on tuning at?
28-30Hz with ample port area

You played with enclosure size to see if you could get away with a smaller enclosure for the jbl's?
I guess I could go with a ~5 cu.ft. ported enclosure for 3x W12GTi's - it only seems to loose 1-2dB over a ~7 cu.ft. enclosure in the grand scheme of things (basically the same size as a box for 2x 13W7's).

Apparently, the W12GTi's high Bl force makes it somewhat immune to box volume. I might have to use this to my advantage :)

As I posted in the "Are the JL W7 Subs played out" thread - I'm leaning back towards the trio of W12GTi's for the time being. I'm a fickle man, so this might change a few more times before I actually build the box :p I'll have to live with the box and see if I'm happy with it's overall size AND output.

Thanks for all of the rational input!!! :cool:
 

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Based on your info: 5cuft enclosure and your power available
The 3 x W12Gti wins in my modelling - below 50Hz they are about the same & above 50Hz the W12Gti wins

If you can, I'd go with a 5cuft enclosure tuned to 25Hz with a 5.5"x14" port area - use a subsonic @ 20Hz 12dB/oct slope

Loud, flatter & no real peak in the passband, port area should be enough for no port noise and goes low without worrying about over excursion ;)

Kelvin
 

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Discussion Starter #20
That's roughly what I'm planning on, but I might tune a wee bit higher than 25Hz. I'll play with that once I settle on the exact volume envelope I want to utilize. I'm aware that Group Delay improves the lower you tune - and that is a consideration.

I'll be picking up the 4Runner from the dealer on Thursday (WOOT!!!!!!!!!!!!), and I'll get to see how big 5 cu.ft. vs 6cu.ft. vs 7cu.ft. will actually be with the cargo space I actually have available.

It seems like the GTi's aren't significantly constrained by smaller boxes - so how large the box design "feels" in the cargo area will likely be what dictates my final box volume in the end. I used to fill up my vehicles (4x 18"s in Mazda B2200 Extra Cab, then 8x 18"s in a snug-top, then 2x 18"s in the old '87 4-Runner), but my last two systems in the Tacoma Xtra cab were quite a bit more compact but still had some authoritative output :) I dig that!!!

It's about time to rip this new truck apart :p
 
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