BEST subwoofer performance - DIY or Production?

Oh here we go again.... get your flame suit on...

I can't tell you to build that IB or not. That's really up for you and the wife to discuss...

But regarding shear performance potential, DIY or production?

DIY, all the way.

100% dual 18'' IBs for 90% HT. The JL subs will NOT even touch the performance of IBs. When you started this thread I thought you were looking for sound quality, something DIY can't match the best production subs. For superb HT performance DIY (especially an IB setup) will not only give you performance that can only be achieved by multiple commercial subs, and also have a much more wallet friendly factor.

The dual 18's will easily outperform the JL subs.

Actually, in a room that large, even the dual 18's would be kinda...wimpy. Woooo!!! For the price of two F113's you could very well have a dozen 18's and still have money to spare. Hell, I'd get off my lazy butt for a deal (GREAT VALUE? No way!) and build that over a couple of lil' JL subs...

... but that's me.

What is the definition of "performance" being used in this case?

In my opinion I don't think it matters how you define performance in this instance. The quad 18's in an IB will walk all over dual jl f113's.

In every aspect of measured performance?

I'm hesitant to say yes but I honestly can't think of any measure of performance where the jl's would exceed the IB. However, that's just based on what I've read.

One could certainly argue that a commercial sub would give you more placement options which could be a big factor in performance if the placement of the IB isn't carefully chosen.

In this forum, there is a lot of emphasis placed on certain measurements. I don't doubt IB has incredible potential, but I have not seen measurements, or even in room comparisons.

Also, as you have pointed out, placement needs to be chosen carefully, and I am not sure those that go the IB route always have that flexibility.

Such an IB would outperform dual JLf113's in almost any metric I can think of. Only group delay would be similar, the JL being sealed is about the same.

Outperform.... But are we talking about SQ here or just SPL...

To each his own, but I did literally lol at that. I do ridiculous stuff to save 20 bucks, let alone 3 grand

An IB is just a really large sealed sub. So everything that makes the JL good is multiplied by the larger enclosure size of an IB.

A DIY "box" sub can be better than a commercial sub for a given amount of money but the construction and design has to be done right.

I think the gist of the first post is, "can we build a sub as good as that from a company" and the answer is yes.

Actually, this is where the IB will do much better. Measurements clearly show an additional electronic high pass on the JL in the teens. In a confined room an IB will extend significantly deeper and more powerfully (below 16-18Hz). There are a select few sealed subwoofers on the market which actually have a low frequency roll off that follows the 12dB/octave low end slope of an ideal sealed subwoofer. While the differences tend to be seen where the response is at least -6dB from maximum, in many real rooms the difference becomes obvious with LF gain from the space factored in. At the same time, a high pass is a design choice which helps keep the sub behaved to a bit higher playback level for a given soundtrack than if it was not in place.

The above noted, I think many understate the value in a known and verified end result. The comparable quality of a DIY sub relies on the diligence of the builder, and the persistence in optimizing the behavior. In most cases DIYers simply up the quantity and capability by a few factors to reduce the likelihood of any limits being reached. This is most certainly a good approach with definite benefits, but when the behavior approaching linear limits is factored in, real world performance isn't always 1:1 on the measured maximum output. Sure, a 4:1 output advantage with a solid, safe design will most likely have real benefits, but when the capabilities start converging at all due to size, power, or placement limitations, the "winner" is not always so cut and dry.

Just some added food for thought.

Thigpen Rotary sub with an IB array for the higher bass.

http://www.rotarywoofer.com/

As for if the IB is the best sub design out there, I would say yes if you have the ability to build an IB sub then there is no reason not too....most people can not build one.

They are also extremely easy to build, far easier then a sealed or ported box that needs to be finished.

I have an IB array in one room and 3 subs in another room (2 ported/1 sealed). The all perform very well for me in the end and I love them all. ALL are DIY subs.

IBs are all about multiple drivers so comparing to one or two sealed boxes is kind of silly and unlike a sealed box an IB array does not require lots of power to get really low frequencies. Its easy to driver 4 Q18 from ficaraudio with just an EP2500 and I can get below 10Hz with great SPL. Remember IB designs will have HUGE displacement (example mine has 27 Liters of displacement), You would need probably 8 JLs to compete!!

try 5-10x as much

My IB array costs $1500 total...that is one PB13 sub...you would need 6 of those subs to compete... Do the math

When you said "two high end prodcution subs", the first thing I thought about was two Elemental Design A7-900s. Then I saw Wife Acceptance Factor and that was the end of you getting 2 Ed A7-900s.

Tom Nousaine has tested hundreds of subwoofers and most of that data is captured in this post:

http://home.comcast.net/~frank_carter/Nousaine.htm

If you scroll to near the bottom of the page, you will see his measurements of the 4 largest IB systems he had tested (as of several years ago), along with a measurment of his own IB system.

I guess for the sake of consistency with the hundreds of commercial subs he has tested, his output measurements are only from 25Hz-62Hz. Tom's IB put out 120 db in from 25-62Hz.

The most powerfull commercial sub Tom has tested and released data on is the Genelec HTS6 which costs ~$10,000 and is 21 inches X 22 inches X 57 inches. The HTS6 delivered 118db from 25-62 Hz.

If you have not seen this article about the build of Tom's IB, here is the link:

http://home.comcast.net/~infinitelyb...usaineIB1.html

Note that he hit peaks of 129 db and said he was going to continue working with the design to get to 131 db.

Really? Wow, that's pretty sweet cause a single one of my 18's can do that too. It's about the same size so it wouldn't be acceptable to the majority of people out there. Didn't cost $10,000 for one though. More like $1,300 for two.

Gotta love that DIY value.

EDIT: Woops. No wait. Each one of my subs are about TWICE as big as a single HTS6. Sorry. Busy at work (heh), all the numbers combined. Heheh.

What other measurements do you have for your sub?

Which ones are you interested in?

Decay and distortion.

Mmmm, well, I can't really provide that for you. My subs were built by yours truely. I do not have any measurement equipment and I am not a professional. Just professional performance.

I can tell you that those both are very low as the particular design mimicks a sealed subwoofer until just near Fb which is in the low teens. Group delay and distortion is incredibly low with my design.

Check here for something close: http://www.hometheatershack.com/foru...rted-270l.html

It's a test on a TC-2000 (15 inch) which my SoundSplinter RLp18 is based. The motor is near identical although the RLp is actually even beefier than that on the original TC2k motor. As you can see in the tests, the distortion if VERY low for what was built. My subwoofer has an even greater Sd (18 inch over a 15 inch) so distortion will be even lower. Also, the sub I built is tuned to 11hz so chuffing or any kind of port artifacts is nearly non-existent.

In the tests for the TC2k (15inch) the 3rd harmonic distortion stays below 10% @ 105dB at 15hz. Below 1% from 20hz and up.

Can you really say that performance would be similar?

I don't doubt that you think it sounds good. I don't doubt it has great performance.

I'd love to hear a highly respected DIYer's sub. I have not had the chance. So in lieu of a first hand experience, and not meaning to start a flame war, it would be nice to see some measurements when I read "my DIY sub is better than a production sub", otherwise, IMHO, it is just chest beating with nothing to back it up.

How about actually listening, does that count for anything in audio anymore? I know my DIY subs sound better than my SVS subs I had. Not even close for HT and music.

Absolutely, it is my preference......but like I said, I haven't had the chance to hear a DIY sub....."So in lieu of a first hand experience", how about measurements?

Also, this is not a knock, because I am partial to what I own...or else I wouldn't own it. IMO, DIYers are even more partial.

I used to have a Definitive Tech PF15TL way back. At the time, it was a pretty respected subwoofer. Cost me about $700. A few years later I built my first DIY sub, an Adire Tempest 15. In total it cost me about $400. Completely blew away the Deftech. Went louder, went deeper and it sounded better too. Still use it to this day and it is awesome.

I may not be "highly respected" but I have been around for a long time now. I have seen many others have the same impressions from their DIY efforts. Many also collect commercial subs too so I can assure you there are plenty of 'comparisons' out there online if you look.

I had the same sub. It was my first one. Now I have a SeatonSubmersive1. No way for me to do a DIY and I can't install equipment myself(no mail order). So, that was the best choice for me. No regret on my end at all. But I have no doubt that some of these DIY and IB systems kick major butt.

Now I know why some people refer to certain subs as refrigerators. If you wrap the stacked pair in stainless steel, people may mistake that room for the kitchen

I would most likely end up with a pair of Epic Conquests. 108 db @ 12.5 Hz. DIY is just not an option.