DIY Subwoofers - General Discussion

**KDspiv** · **09-22-09, 06:45 PM**

I am kicking around building a sub that will try and serve two masters....music and home theater.
But here in lies the rub: I need at LEAST a 12" subwoofer with a respectable xmax in a ported enclosure to fill a large open living room with 2 story ceilings. But it has always been my understanding that the recovery time on a twelve with a large xmax is poor for music unless placed in a small sealed enclosure . There for a 10” sub driver is preferred for its speed but SPL is given up.

IS THIS STILL TRUE? Hell, it may have never been true but that is what other fellow AIS’s (audio idiot savants) have always told me.

Soooo……are there any 12” drivers available to the DIY world that can provide musicality to match my main speakers but rattle sheetrock off the walls?
If you were trying to replace a JL Audio Fathom F112 (which has become my benchmark) with a DIY project……..could you do it? This sub had a startling amount of bass but still did well when I asked it to play my favorite music. (And DeadSpace was great too)

Recommend a driver to me (if a retailer reads this and thinks they have what I need, then let me know too) so I can get started on research and developing!

**tonyvdb** · **09-22-09, 06:53 PM**

"Historically, 10” were the best size sub-drivers for music….Is this still true?"

No, Not any more. just for an example I have an SVS PB13 Ultra, it has a 13.5" driver and does music really well as a matter of fact I have one of those 10" subs you refer to and it did what I thought was a great job with music but the PB13U is even better. The smoothness of the lows below 20Hz is fantastic and is still very "fast" at the punchy bass in the 40Hz range.

**Kevin Haskins** · **09-22-09, 06:56 PM**

There is no truth to the 10" vs. 12" vs. 15" subwoofer having any direct correlation with sound quality outside of the obvious differences in headroom. Often, the limited bandwidth subs sound more musical because they don't excite as many room modes. It is as much to do with the room-subwoofer interface as anything so you should dedicate some time to learning about the issue. My standard recommendation is Toole's book. It covers subwoofers and a lot of other topics and it is based upon research, not opinion.

The Fathom is a good sub. It is essentially a small heavily equalized subwoofer with lots of power. If you are willing to live with a slightly larger enclosure you gain a lot. Read about Hoffman's Iron Law (Google).

I'd do some reading before I'd spend any money or talk to a company. There are so many people with different views in audio if you spend your time asking for opinions, you will come away more confused than when you started. Do your homework and buy Toole's book and do some reading about basic subwoofer design and room acoustics. That knowledge will take you a long ways and save you a ton of money.

Kevin Haskins
Exodus Audio

**tonyvdb** · **09-22-09, 07:13 PM**

I agree with Kevin, I should also add that the real reason that we now have subs as large as 18" is basically because of Movie soundtracks. The digital audio formats as well as uncompressed audio is giving listeners in there own home bass that goes well into the 10Hz range, unheard of in a home environment up until recently. A 10" sub simply can not go that low with a decent amount of SPL. For music thats just fine as the majority of music rarely goes lower than 30Hz and a good 10" sub can easily manage that.

**onebadmonte** · **09-22-09, 07:27 PM**

For those wondering what book Kevin is talking about, here is a link to it on Amazon.

http://www.amazon.com/Sound-Reproduction-Acoustics-Psychoacoustics-Loudspeakers/dp/0240520092/ref=cm_cr_pr_product_top

**KDspiv** · **09-22-09, 10:16 PM**

I am familiar with that Law. I bought The LoudSpeaker Design Cookbook after the first couple of DIY loudspeaker attempts. In basic terms (and please correct me if I am wrong) the law basically says
1. Low End extension
2. Small Box
3. Efficiency

you may have 2 of 3.

Most of the builds on here seem to be about chest thumping bass. I KNOW there are some true audiophiles who watch a lot of movies on here and figured I might be able to get a few to give my a starting point.

Hell, before I had joined another forum a few years ago, I had no idea who Scanspeak was or that some guy named "Zaph" Krutke (sp?) had designed some amazing speakers using them. And now I have a pair that I built that are my two channel beauties.

**ec114** · **09-23-09, 12:08 AM**

Assuming the cone is small vs. wavelength, which is 11ft at 100Hz, it boils down to frequency response and distortion. If it has the frequency response, and doesn't distort, it's "fast" (not that useful a sonic concept, actually, except in marketing electrostats and such) enough... You want to move air, and to do it efficiently, especially at lower frequencies, the larger the cone, the better.

Without some work, larger cones with their accompanying larger motors naturally tend towards higher inductance, which, without some eq and a high-voltage (-power) amplifier, won't do higher frequencies as well. But add in Faraday rings and such, and big woofers will do midrange just fine, if beamily. Audiophilia nervosa is a funny thing: it leads people to trust their misleading intuitions and come up with "truisms" that are sometimes not. Or so I've heard...

As others have alluded to, it all depends on what you're trying to achieve, what your mains will do, and your room situation.

Oh; concrete recommendation: Maelstrom 18" or 21". Better yet, multiples thereof. Assuming your mains can go below 100Hz (preferably lower) with authority, and your room can take the bass.

**Ryan Anderson** · **09-23-09, 01:55 AM**

Quote:

ec114 wrote:

Oh; concrete recommendation: Maelstrom 18" or 21". Better yet, multiples thereof. Assuming your mains can go below 100Hz (preferably lower) with authority, and your room can take the bass.

tumults, brahmas, avalanches, XBL!

**Mike P.** · **09-23-09, 02:31 AM**

There was a subwoofer get together held a while back and the 12" Shiva-X did well with movies and music. Post #31 in this thread:

http://www.hometheatershack.com/forums/diy-subwoofers/17369-another-subwoofer-gtg-southern-style.html

Depending on your SPL requirements I'm not sure a 12" sub would be enough "to fill a large open living room with 2 story ceilings".

**Mike P.** · **09-23-09, 02:31 AM**

There was a subwoofer get together held a while back and the 12" Shiva-X did well with movies and music. Post #31 in this thread:

http://www.hometheatershack.com/forums/diy-subwoofers/17369-another-subwoofer-gtg-southern-style.html

Depending on your SPL requirements I'm not sure a single 12" sub would be enough "to fill a large open living room with 2 story ceilings".

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