It certainly isn't "the bar", when the comparison is being done with 12" drivers in ~100L boxes.
My POC3 is supposed to be able to do 98dB/2.83V/1M AND reach down to 40 Hz, and I would not choose to compare it to any decent 18" BR box, particularly a comparison based on sensitivity alone. That's because it runs out of steam in its passband at less than 100W (when loaded with the PA310), and the 18" driver will likely remain linear at much higher power levels.
Comparing against another system in the same or similar box size is the way I'd go, and even then only if the lowest resonance frequency is similar. Otherwise we are basically trying to compare two different systems that had different design goals.
Nope, that's the POC3, equipped with the Kappalite 3012LF driver. On top are my Blastoramas.
For your needs, you will likely want to go louder than the POC3 can achieve, even with the Kappalite driver, especially as you're "downgrading" from THAM15s.
If you're wanting small with a lot of output capability, it's hard to compete with the bog-standard vented box with a good driver, particularly these days when amplifier power is cheap. Off the top of my head, a Dayton Audio PN395-8 in a 2.5~3 cu.ft. box tuned to 42 Hz with corner vents might actually do pretty well as a small vented box that can get loud with the right amount of power. For a higher cost, the B&C TBX 15" can give you even more output, but you'll need more power to get it.
I would suggest comparing against another system with similar design goals, e.g. size and lowest resonance frequency. And compare not only sensitivity, but peak linear SPL capability, which is also important for pro audio use.
FWIW, a Dayton Audio PN470-8 (an 18" new driver) can be used in a 100L (net) box tuned to 38 Hz. Sensitivity would be 97dB/2.83V/1M, but peak output is up to 123dB with the driver remaining in its stated Xmax range (48.5 V, or just over 400W input). What is the peak SPL capability of the Cubo 12?
As I mentioned previously, that's a POC3, not a POC6. However, I was curious as to how many POC6 boxes I can get in the trunk of my vehicle. Turns out I can fit two, with a little space to spare (the picture shows only one, but it takes up only half of the trunk, so...)
I think I lucked out here there. It certainly wasn't designed with optimizing trunk space usage in mind.
For a design I did for someone with available trunk space in mind, check out the link below. The subs in question were two 15" THs folded THAM style, but dimensions adjusted to fit in the builder's vehicle, with the rear seat folded down. These were designed before semi-inductance parameters were available for the drivers used, so it's quite possible that they can be improved even further.
SS15/THAM15/keystone/other for 12v outdoor party
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Well, I researched the market and diy-scene from 15 years back, up till 10 years back reaching that conclusion. From the cheapest brands all up till the most expensive manufacturers, most have several single or double 18" reflex cabinets in their catalogue. Many designs with 21" drivers are a bit more exotic, so 18" drivers are the largest mainstream transducers.
Whether you're looking for a drum monitor, to fill a full grown stadium or anything in between, reflex cabinets have been used for over 50 years. And with a bit of imagination even a EAW SB1000z can be transformed into a PPSL
Best regards Johan
I think this kind of box would be ideal below my Fane 12-250TC boxes. I wonder if Delta12LFA could be used to get some meaningful output at the low end (I have a pair laying around). I did some crazy modifications - and got some low end extension at the cost of efficiency and box size...as expected
I got back to this box type and came up with this. I am pretty sure someone could improve on this - but a 110 l box with Delta 12LFA is not too bad when crossed over at 100 Hz I guess - and that is all I need. Anything smalled than my > 300 l bass horns will be space saving
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I played with the foldings and Hornresp and I compared the MLTL to a BR with the same port size and volume. I found the only difference in the group delay, the MLTL is ca 5 ms better. Is that worth one extra piece of wood? I think yes. And please keep in mind, this is intended as a home subwoofer with 100 W max and proper highpass. And I have two Delta12LFA speakers left from another project, so I think I will build a pair. I must say, the Excel sheet is a really nice tool, thanks!
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