Originally Posted by David Simpkin
I'd also like to know this, an example I can think of is the extremely high end and pricey paradigm sub 2.
Why have they gone with 6 10" drivers? Is there good reasoning behind this vs say 2 18" drivers which would have very similar cone surface area?
Let's do the math!
Say we will compare six Dayton Audio Ultimax 10 inch subs VS two Ultimax 18's--we will just worry about how much air they can pump since down low is what you are concerned with.
Subs are air pumps, it is bore X stroke just like in engines--this will give you liters of air the thing can move. (Plenty of other factors but you'll get the idea.
Bore (Sd) for the 18" is 1219cm2 while the bore of the 10 is 328cm2 Basic division indicates it will take 3.7 tens to equal the surface area of the 18.
Stroke (Xmax X 2) for the 18 is 44mm peak to peak and the 10 is shorter at 38mm peak to peak
Bore X stroke or 1219 X 44 for the 18 and 328 x 38 for the 10 = 5.36 liters for the 18 and 1.25 liters for the 10
Two 18's would displace 10.72 liters of air while six of the 10's would give you 9 liters of air displacement. If you wanted to duplicate a pair of 18's, it would be better to use eight 10's instead of six of them.
There are other factors, efficiency higher up in frequency VS efficiency lower in frequency, the ability of 18's go be tuned lower than 10's and so on but you get the idea.
So why would Paradigm build a sub with six 10's because a pair of 18's would offer better performance? Simple, because it was not built for performance! It was built to be different, a "halo product", a hexagon instead of a box or cylinder--a different spin that looks cool. There is nothing wrong with that, plenty of speakers and subs give up performance for looks, style, size and so on. Charging 10 grand for it makes it obvious it is more a "lifestyle" product where looks, style, uniquness and that sort of thing play out. Rather complex way to do it so that costs money, at 10 grand Paradigm probably does not expect to sell many of them--but that is not the point of a halo product. Most audio companies have done that long before any of us were born--plenty of people don't mind that, explains such things like a $15,000 purse or a $20K mechanical watch--it's not about holding your wallet and lip balm or knowing what time it is.
Some consumers actually believe that if something cost more, it is better! That's what TV, radio, advertising and everything else have been telling you since you were born. This is why you become an "educated consumer" and decide how much you wish to spend for looks, finish, uniquness VS performance of a product be it subwoofers, cars or condoms.
Nothing against Paradigm, they know their target audience and what people that purchase their products desire. Instead of getting in a subwoofer "war" where performance is the only thing--they chose (wisely) to offer something different, matches their whatever speaker line and allows all sorts of fun with words from the marketing department. Nothing wrong with that, it keeps the lights on and the profits spend the same no matter if they bought it because they wanted a certain performance level or it matched the curtains better.
The other factor to think about, the DIY crew generally speaking is very performance oriented--BassThatHz has world class performance and yet--his quad amped speakers are raw MDF. Plenty of 10 in subs around, very good ones from the Ultimax 10's to the CSS SDX 10 beasts to play with. The issue is when you want to get high SPLs down low, under 20Hz and for conventional subs (sealed/ported/passive radiator) there is no replacement for displacement. If your goal is performance, you put the budget toward that end. Say I wanted to "equal" a pair of 18's with tens--I'd use eight 10's to do it. Cost would be around $1,100 just for the drivers, much more hassle to cut all those holes, seal all that stuff--more parts, more problems! What is better than a hexagon? An octogon! The CNC milling machine will make easy work of it but the cost is the veneers--more veneer pieces, more chances to screw it up.
In DIY you can do whatever you want---one guy built a massive horn loaded subwoofer and cloned the Tardis from Dr. Who. Looks like a British phone booth....but it is a sub. For this reason, you rarely see "clones" of designs that don't provide performance as the main design principle. Sure, the DIY crew builds really small subwoofers but will make very oddball sizes to better fit their room--custom builds abound for that. My pair of 15" subs in the garage are 6.1 cubic feet tuned to 18 Hz with the port "under" the box so it looks like a "floating end table"--the dreaded WAF they call it. It's not like I can amble down to Fast Eddies Audio Shoppe' and pick up an end table subwoofer of a specific size, specific shape, exact veneers and the exact table top my wife likes. The true design challenge was to stealth the sub at a size that did not throw away performance for looks--I really wanted to use 18's but something that huge would not work. The joy of subwoofers is you can always add more. I'm going for three of them...for now.
As far as the PB16 goes--it would be easy to "clone" that one by purchasing that Peerless driver--generally speaking, it does not model well if you can go with a slightly larger box. I did model the driver, looked at the results and the juice was not worth the squeeze. For others, it might be the perfect performance at the perfect size--then go for it! For me, I'd rather go more subwoofers (three) than a pair of crazy subs. Once you learn how to model subwoofers, then you can play around with all sorts of alignments from way too small sealed boxes to massive LLT (Large Low Tuned) boxes or dabble with horn loading. The software will give you a very good idea and you can have multiple proposed builds on the same chart--pick the one that suits you best.
In summation, I'm not saying nobody has ever "cloned" the Paradigm sub--big world out there. However, once you do start building subwoofers, reading/understanding the charts/software, most likely you'll look more towards performance as your guide. This usually eliminates designs that are more a visual thing than a performance thing. All depends on what performance you want, your budget and how much you are willing to part with for finishing.
Hope that clears things up a bit for you--the rabbit hole runs deep here so watch where you step!