BillFitzmaurice.info

A T48 is massive, and rules out future plans for deploying the tops and subs as a smaller standalone PA system for open deck nights, etc.

jHands, I was wondering if you were planning on running on running one sub under each top...sort of a Left and Right.

Tom Smit wrote: ↑Mon Nov 24, 2025 11:09 pm

A T48 is massive, and rules out future plans for deploying the tops and subs as a smaller standalone PA system for open deck nights, etc.

jHands, I was wondering if you were planning on running on running one sub under each top...sort of a Left and Right.

That's correct. T30's likely to have OT8's on top.

There's no need to do that, as the radiation pattern of subs is 360 degrees on both the vertical and horizontal, and content below 100 Hz is the same in both the left and right channels.

Bill Fitzmaurice wrote: ↑Tue Nov 25, 2025 7:44 am There's no need to do that, as the radiation pattern of subs is 360 degrees on both the vertical and horizontal, and content below 100 Hz is the same in both the left and right channels.

Not sure what this is in response to, can you clarify?

Why you need two subs.

jHands wrote: ↑Mon Nov 24, 2025 11:32 pm

Tom Smit wrote: ↑Mon Nov 24, 2025 11:09 pm

A T48 is massive, and rules out future plans for deploying the tops and subs as a smaller standalone PA system for open deck nights, etc.

jHands, I was wondering if you were planning on running on running one sub under each top...sort of a Left and Right.

That's correct. T30's likely to have OT8's on top.

I thought so. Have a read here..... viewtopic.php?t=398

Tom Smit wrote: ↑Tue Nov 25, 2025 10:23 pm

jHands wrote: ↑Mon Nov 24, 2025 11:32 pm

Tom Smit wrote: ↑Mon Nov 24, 2025 11:09 pm
jHands, I was wondering if you were planning on running on running one sub under each top...sort of a Left and Right.

That's correct. T30's likely to have OT8's on top.

I thought so. Have a read here..... viewtopic.php?t=398

Very informative post thank you for sharing. It seems as if my rig would be ok - the subs are 2.8 feet apart or closer with how I’ll be deploying them, with the tops slightly to the outsides.

Bill Fitzmaurice wrote: ↑Tue Nov 25, 2025 9:59 pm Why you need two subs.

Would two subs in close proximity not achieve higher SPL than one?

Sure, provided you have the power to drive them with. If you're using a 12v battery or two you probably don't. An E-Bike probably doesn't have the power to pull two subs either.

Bill Fitzmaurice wrote: ↑Wed Nov 26, 2025 7:12 am Sure, provided you have the power to drive them with. If you're using a 12v battery or two you probably don't. An E-Bike probably doesn't have the power to pull two subs either.

Perhaps you can double check my math and logic here...A 300 ah 12v LIFEPO4 battery has 3840wh of capacity. Coupled to a 3000 watt inverter has some decent run time...The rig only needs to run in battery power for 4 hours, for my usage. For stationary parties, it'll be on a genny. The events I'll be deploying it at usually go: meet and greet at a park for about an hour, bike ride around the city for 2 hours, reach final destination and party until sunrise.

If my calculations are correct, using an amplifier such as the NX3000 by Behringer, the 8 ohm load is 440 watts. That means 440 watts of real energy usage, but only during moments in the music that require peak excursion. The DJ equipment and lighting use barely any power. The tops are only going to get about 200 watts, and again, peak wattage only occurs momentarily in music. I can see how it would be more energy efficient to run one sub, and I am definitely considering this. One 15 at 6 ohms also gives me the ability to run car audio amps, and then wire the OT8's for 4 ohms, also allowing me to use car audio amps....hmmmmm

If I were to switch to a single, larger sub, that can lay on its side, does the vent mouth need to face the crowd? I am contemplating a tube firing tuba, and leaving one end of the cart open, either the leading or trailing end.

The e bike is not a problem, I can assure you of that. I am procuring a European built e-trike with a 450lb payload capacity. It also has a rack on the back that I intend to carry a spare battery with. The build will incorporate a small UPS that allows for seemly transitions between power sources.

I thought I would put this out there. Unfortunately, there is no chart to a 12" driver in the T30.
T30 to be high passed at 35hz, T39, at 45hz, and T48 at 40hz.

jHands wrote: ↑Wed Nov 26, 2025 12:09 pm If I were to switch to a single, larger sub, that can lay on its side, does the vent mouth need to face the crowd?

Bill Fitzmaurice wrote: ↑Fri Nov 21, 2025 9:32 am

jHands wrote: ↑Fri Nov 21, 2025 12:16 am With regards to the T48, can it be used horizontally?

Like any and all subwoofers it can face in any direction, so long as the horn mouth isn't blocked.

Tom Smit wrote: ↑Wed Nov 26, 2025 10:52 pm
I thought I would put this out there. Unfortunately, there is no chart to a 12" driver in the T30.
T30 to be high passed at 35hz, T39, at 45hz, and T48 at 40hz.

Thanks for posting that. I wonder what that T30 chart would look like with a Lab 12? I know the sensitivity would go down, but I'd bet it would be lower.

This link will show the 3012LF in two different width cabs. Lab12 response will be quite similar. Lab12 was an option when Neodimium was in shortage, but the Lab12 is considerably heavier. There is no sonic advantage to the Lab12.

https://billfitzmaurice.info/images/SPL ... 0-inch.gif

"I wonder what that T30 chart would look like with a Lab 12? I know the sensitivity would go down, but I'd bet it would be lower."
The cabinet dictates the response regarding extension. Diff drivers may give more dB AT said extension, but the bottom end is what the horn length provides. The truth HERTZ. (Sorry for the bad joke.)