BillFitzmaurice.info

Has anyone seen these drivers? All specs are within measurements on plans and they have some serious output (wattage and displacement). my question is has anyone ever done a swap of drivers? I currently have the 3012lf in my boxes and was thinking of swapping them to get more output. Also you guys think it’ll be worth it in terms of output? I know they cost quite a bit more but that doesn’t concern me.

In the T30 it has about 3dB more maximum output than the 3012LF. I wouldn't call that cost effective.

Bill Fitzmaurice wrote: ↑Tue Aug 10, 2021 9:10 pm In the T30 it has about 3dB more maximum output than the 3012LF. I wouldn't call that cost effective.

Only 3dB that sounds low for almost double the displacement specs but you are the one that made the plans so I trust you. I have 4 dual t30s and was eyeing these. Maybe if I build more.. thanks Bill

To get 6dB more output you have to double it, which means 18mm in this case.

Vd... based on stated xmax.
3012LF - 496cc
12XL1200 - 584cc
LAB12 - 659cc

Rickwired wrote: ↑Wed Aug 11, 2021 7:54 pm
...I have 4 dual t30s and was eyeing these...

If you end up swapping some of those 3012LF's out... I'm interested in 4 of them (or all 8 at the right price). Drop me a PM if ya go that route.

Rickwired wrote: ↑Wed Aug 11, 2021 7:54 pm ...Maybe if I build more.

Rick, if you converted your existing cabs to single driver (just remove 1 driver and screw a gasketed disk in it's place) and doubled your cab count to 8 single loaded cabs, you'd have a decent gain in output for only the cost of ply, construction time, and consumables.

There isn't a chart for your exact width but here's 4 double 3012LF loaded 27" wide cabs (RED trace) compared to 8 single 3012LF loaded 27" wide cabs (BLUE trace).

Is that 107dB @30Hz for 2.83V?

Chris_Allen wrote: ↑Sat Aug 21, 2021 9:10 am Is that 107dB @30Hz for 2.83V?

I believe so. But I couldn't say 100% without verification that the double loaded cab was measured at 2.83. It appears to be consistent with what I'd expect to see at 2.83 though.

And, that's 2.83 into 8 drivers. So, 8 "watts" total. 4 double loaded cabs vs. 8 single loaded cabs of the same width. I added 12dB to the double loaded trace to account for 4 cabs and +18dB to the single loaded trace to account for 8 cabs.




I think the 3-5ish dB gain from 33Hz up sells the scheme, big time. Same number of drivers, same amplifiers... just 4 cabs worth of plywood and time get's 3-5dB. That's huge gains for pennies.

They won't chart like that. Response will be considerably flatter, with less rise above 60Hz, and the low frequency corner will go down by 5Hz or so.

Bill Fitzmaurice wrote: ↑Sat Aug 21, 2021 10:57 am They won't chart like that. Response will be considerably flatter, with less rise above 60Hz, and the low frequency corner will go down by 5Hz or so.

It is certainly a static comparison that doesn't take into account the realistic benefits that occur when coupling multiple cabs and isn't a 100% accurate representation of a real world result. Would you say it's a bad idea to compare cabs in this way, just to get a rough idea? If so, I'll keep that in mind for future posts and either not do it or include a little informational disclaimer for the less informed.

You should clarify the effects of multiple cabs for the benefit of those who aren't aware of them.

Bill Fitzmaurice wrote: ↑Sat Aug 21, 2021 12:02 pm You should clarify the effects of multiple cabs for the benefit of those who aren't aware of them.

I've scoured low and high. I feel as though I may be overlooking it... I swear there was a sticky thread that spoke to the benefits of stacking and V-plating, but I can't find it or anything resembling it anywhere. I have a feeling it's one of those things that's right in front of me and I'm just not seeing it. Does it exist or is my memory losing it's grasp on reality?

This one Seth viewtopic.php?f=10&t=398 ?

Tom Smit wrote: ↑Sat Aug 21, 2021 11:04 pm This one Seth viewtopic.php?f=10&t=398 ?

That's the first place I looked. But, it doesn't mention anything about the benefits of stacking multiples, just how and where to do it. It does mention the benefit of V-plating though.

I looked in the SPL Chart section too, where it illustrates the effects of stacking multiple cabs with response charts for multiple T24's, T39's, and T48's. But, there's no mention of the effects there either.

I also checked the T39 and T48 plans. No dice. I can't remember where I read the information. It's good information and Bill is right, I should include it with charts like I posted above. Was thinking I'd add a disclaimer and a link to the information. But, I can't find it