10" vs. 12" subwoofer, I was having this discussion and...

[mlekk]

Two of these sealed ?
https://www.audiolegionusa.com/produ...SABEgK2WfD_BwE

[Hillbilly SQ]

Not familiar with that brand but I'd do a single 12" over a pair of 8's if the install will allow it.

[Grinder]

If available space isn't an issue get the biggest QUALITY sub you can fit and give all the space it needs. I've heard 18's be tight and punchy and I've heard 8's be loose and muddy. So many variables like quality of woofer, box, placement in vehicle, and so on and so on. The biggest mistake I see a lot of people make is they don't let the vehicle tell them where it wants the sub to be. If the install is crap the subwoofer will also sound like crap even if you built the perfect box for it. There are also A LOT of bad subwoofer designs out there that aren't really going to sound good no matter how much work you put into the box and install. On top of that you can't forget Hoffman's Iron Law. There are three things you want out of a subwoofer (small box, play the lowest octave of 20-40hz with authority, and high output). Problem is you can only have two of those things at any given time. I think I got that right but am a little rusty. Choosing the best sub for your needs isn't rocket science but it still takes at least some degree of understanding of what the speaker was designed to excel at.

I've had a 10" and a 12" of the same subwoofer (Dayton ho10d4 and ho12d4). The 10" actually needs about the same size box if not a hair bigger than the 12" believe it or not...at least for the d4 version of each sub. The 10" sounded good but I wanted MORE of it. It also struggled like crazy under 40hz. The 12" version excels under 40hz. Erin has heard both in my truck so he knows what I'm talking about.

One other thing worth mentioning is you MUST model all voice coil configurations of any given sub to make sure you're not going to end up with an air pig in one coil configuration when you thought you were buying a sub that needs a really small box. Take the Dayton ho10 single 4 and ho10d4. The single coil version does quite well in about .3 cube sealed. The d4 of the same woofer needs nearly double that to be happy. Anyone who thinks I'm full of it needs go model both and report back with their findings. I've run into this issue with other subwoofers too over the different coil configurations. Most people probably wouldn't notice if a sealed box is a little out of spec or even a ported box for that matter so almost never worth getting too technical with the 99%.

*Efficiency*

More on Hoffman's Iron Law, for those who might be interested:
https://www.glasswolf.net/papers/hoffman.html

https://en.wikipedia.org/wiki/Josef_Anton_Hofmann

[TheTodd]

There are three things you want out of a subwoofer (small box, play the lowest octave of 20-40hz with authority, and high output). Problem is you can only have two of those things at any given time.

This is why I love my IB 15”. I technically get all 3. I say technically because I know that by going IB it’s actually a very large enclosure but if you think about the fact that with a 15” sub I only sacrifice about 7” of depth (the physical depth of the woofer) so I have my ENTIRE trunk, plus it’s crazy efficient (it can get stupid loud on only 400w), and it plays extremely low with ease, authority & balance.

[mikeyt]

I'm glad I threw this out there. I knew I would be getting some more techie stuff out of it. And by these posts, looks like you guys are having fun with it as well. I see Todd you are using an Fi sub, how do you like it. I'm considering using a XV3 for a build in my daughters' 4runner. I understand they are pretty good for SQ which is what I'm after with some boom to go along with it.

[TheTodd]

I’m not using Fi. I’m using a cheap PPI Phantom 15” in IB (infinite baffle).

[JCsAudio]

I can model them in Bassbox Pro but generally a ported 10 will have more SPL at the tuning frequency than a sealed 12. I tried this once with a sealed Alpine SWS 12 vs a ported Alpine SWS 10 and the 10 was louder. If the box is built correctly and tuned low then a ported enclosure can have less distortion at higher SPL than a comparable sealed setup because the subwoofer cone moves less at fb and with cabin gain removed with a DSP cone control is even better.

[mikeyt]

I was thinking along those same lines, but had really no way to back it up as far as the modeling goes. Just the train of thought of what a sealed vs ported box can do, i.e how it changes the way a driver works if you will, I may have that wrong too...lol