Why IB Sub?

**willy-be** · **02-17-08, 12:04 PM**

Quote:

NickTF wrote:

An IB does not, it's backwave is in another room, atleast if implemented correctly.

I was drawing a parallel because in either situation the drivers are operating without benefit of a box. This seems to be one of Steve's major points of contention.

A few years ago I heard a pair of Orions, they sounded natural and life like. My assumption is this would be the same situation with an IB sub, but Steve says it isn't so, thus my confusion.

Aloha,
WB

**NickTF** · **02-17-08, 02:22 PM**

Quote:

willy-be wrote:

I was drawing a parallel because in either situation the drivers are operating without benefit of a box. This seems to be one of Steve's major points of contention.

A few years ago I heard a pair of Orions, they sounded natural and life like. My assumption is this would be the same situation with an IB sub, but Steve says it isn't so, thus my confusion.

Aloha,
WB

I've had a very nice LLT setup (Two tc2000 15s and two 18" vmp radiators) and now have an IB. I do have more displacement in my IB though so consider that when I say the IB is much much realer to me. Numbers and graphs are nice but listening impressions are what drive me to select audio equipment and thus far I couldn't be happier that i've selected the IB route over my previous LLT. Everything just works better with it but like I said I did upgrade the displacement.

**DRB** · **02-17-08, 08:07 PM**

FWIW, the most realistic sounding bass I've heard in a home theater used an IB setup. (The best bass I've heard in a car used an IB setup as well; the trunk was sealed off from the cabin with the subs blowing through the rear seat).

Somehow I suspect that the mere mention of 'car audio' will annoy someone. I hope not.

**NickTF** · **02-17-08, 09:02 PM**

Quote:

DRB wrote:

FWIW, the most realistic sounding bass I've heard in a home theater used an IB setup. (The best bass I've heard in a car used an IB setup as well; the trunk was sealed off from the cabin with the subs blowing through the rear seat).

Somehow I suspect that the mere mention of 'car audio' will annoy someone. I hope not.

Uh, the mention of car audio may not bother anyone but the mention that an IB may actually have an advantage of LLT in any possible way may bother people

**atledreier** · **02-18-08, 12:03 AM**

I've been reading this thread for a while now, and frankly I'd expect nothing less than what I'm seeing. The 'IB guys' defending their 'turf', the 'LLT guys' defending theirs. Of course it'll be like that. A BMW dealer in a mercedes dealership WILL stir the pot.... And with audio at least as subjective as cars we will see the same here. Human nature, you defend what's 'yours', and your belief system. Too bad these systems are somewhat hard to come by, and get demoed properly.

I haven't heard an IB yet. I'm sure I'd like it. It models well, good principle, pretty easy to implement if you have the space. It's different from most conventional setups. Place high demand on the equipment used, and overdimensioning is required.

LLT is more conventional, just overdone. With the low tuning you push some of the flaws of a ported system to a less objectionable frequency range, but they are still there. But you also get the port benefits, and with a vengeance. Since the entire system is built around overkill, the end results are usually awesome.

So which to pick? Sorry, you're gonna have to take the plunge and try yourself, I'm afraid.

**SteveCallas** · **02-18-08, 12:16 AM**

I'm not trying to disinfrachise anyone from going the IB route, just showing an option that will yield more performance for those who already have an IB but are wanting more or are limited in some way, like jagman, without having to purchase more drivers and amplification. The simple fact of the matter is that it isn't really debatable whether or not a LLT offers greater headroom, less distortion, and deeper, flatter extending response compared to an IB. Not unless someone has figured out how to defy physics.

Quote:

willy-be wrote:

Maybe I'm wrong but it looks to me like the IB designs seen in the gallery here really aren't much different than open baffle or dipole speakers. If that's the case you're saying people like Siegfried Linkwitz and others are fundamentally wrong in the way they design speakers?

They are quite different, because as Nick touched on, the backwave from the drivers in an open baffle speaker configuration are not isolated from the front wave. This is definitely not something you would want to do with a subwoofer if your goal is deep extension and high ouput, as you will lose both of those in an open baffle configuration. So your second sentence doesn't really apply, and it would have been a very slippery slope at best if it did, as performance goals for designing a subwoofer are typically different than performance goals for designing a speaker, especially an open baffle speaker.

**collo** · **02-18-08, 01:33 AM**

I'm a fan of IB's since building mine with 12 of the the cheap 15 inch drivers that were available in Australia from Jaycar.

Since those drivers are no longer available, we've had nothing suitable for an IB until the recent arrival of the Tempest-X driver. The problem is that the new drivers give double the performance of the old ones, but are four times the price ($350aud ea!!). This makes a high displacement IB fairly expensive for us. The solution may be to use the LLT solution, as expoused by Steve, and demonstrated by Rodney.

Here's a comparison showing the Tempest-X driver used in a 4 driver IB, a 4 driver LLT and a 6 driver IB that costs an additional $700aud for the drivers. The shaded area shows the gains from the port. A pair of 8 inch ports are OK for velocity, but would be a bit short - you could always go for a pair of 10's

The LLT might be just the shot for those on a limited budget, and with a smaller space to work with.....

WinISD project file for LLT design
Page containing project files and futher details of the IB designs

viva la difference!

**atledreier** · **02-18-08, 03:37 AM**

I'd love to see a group delay plot for the ported VS IB...

**collo** · **02-18-08, 05:34 AM**

As you would expect.....

**atledreier** · **02-18-08, 06:48 AM**

My point exactly. That's gotta be audible, no?

It's sorta like an engine. IB is a bigblock V8, and ported is a high-strung turbocharged inline 4. Of course, an LLT would be a supercharged V8, so...

Advantages and drawbacks with both concepts.

**SteveCallas** · **02-18-08, 09:58 PM**

Quote:

alt wrote:

I'd love to see a group delay plot for the ported VS IB...

Leave the preconceived notions at the door - how about the real world measured group delay from a near LLT?

Well under one cycle even below tuning. But even if I wanted to play devil's advocate, the answer to your question:

Quote:

My point exactly. That's gotta be audible, no?

No, it's not going to be audible. Less than one cycle at an infrasonic frequency will be beyond perception. What will be audible is the flatter, deeper extension, less distortion, and greater headroom - you know, the 800lb performance gorilla in the middle of the room that some don't like to address. For those who live on the fringe of common sense though, don't forget that by adding EQ boost to sealed alignments down low, you are degrading your transient response.....but enthusiasts don't like to talk about that

There's only one legitimate drawback to the LLT which doesn't bother too many and isn't a drawback at all for the SLLT - it's size.

**atledreier** · **02-19-08, 04:30 AM**

Awesome!

I love real world measurements!

That looks like a really neat sub...

Now I'm going slightly OT here, but what is GD really? And how do you measure it?

**Chrisbee** · **02-19-08, 04:41 AM**

Steve

Time to end these circular discussions! Time to put up or shut up!

Since you are a vociferous minority it is you who has to prove the value of your LLT design over the ever-more-popular IB.

Because an IB can't come to you it now behoves you to drag your LLT into someone's HT.

Where a typical, BFD equalised, Behringer EP2500 powered, 4 x 15" IB is installed.

(let's call this an average spec IB for the sake of this contest)

Compare the two subs side by side on the same material after careful level matching.

We'll need a couple of witnesses to ensure fair play.

Now which subwoofer sounds more real on music and film?

**atledreier** · **02-19-08, 06:18 AM**

I've really wanted to try an IB. I have an office through a set of double doors in the rear of my theater. Been toying with the idea of taking the doors off the hinges and making a baffle instead. The office have another door for access anyway.

**Chrisbee** · **02-19-08, 06:32 AM**

The conventional wisdom is that you should not have a subwoofer behind you.

This also holds true for an IB.

Can you reverse your HT layout to bring these doors to the screen end?

**NickTF** · **02-19-08, 09:30 AM**

Quote:

Chrisbee wrote:

Steve

Time to end these circular discussions! Time to put up or shut up!

Since you are a vociferous minority it is you who has to prove the value of your LLT design over the ever-more-popular IB.

Because an IB can't come to you it now behoves you to drag your LLT into someone's HT.

Where a typical, BFD equalised, Behringer EP2500 powered, 4 x 15" IB is installed.

(let's call this an average spec IB for the sake of this contest)

Compare the two subs side by side on the same material after careful level matching.

We'll need a couple of witnesses to ensure fair play.

Now which subwoofer sounds more real on music and film?

(there are really no other questions which matter)

The ball is in your court!

I honestly don't see this happening but it would be really cool if it did. I'm no expert nore even close to one but i've been fulling with audio for quite a bit, about 8-9 years. I've never heard anything near as close in accuracy as this IB. I understand the benefit of the added output of a SLLT but I honestly think it's useless, atleast in my situation. Maybe in a giant room with a concrete floor it's not but in my situation it would be and I think in many's situation it would be. I mean how much more out put do you you guys need ha ha. My old car stuff would do over 140db all day long and this four 18" IB system has much more subsonic power and i'd venture to say all the way up to about 30hz power. That's silly for a home and far more then most main speakers are capable of mustering.

The reason I say this is i'm convinced that adding a ported enclosure to an IB will in fact put sound artifacts in the subwoofer system that just aren't present with an IB. I'm not talking about things you can measure and graph etc., i'm talking about how the setup actually sounds which is really all that matters unless they invent DB Drage Racing for homes. The first time I was convinced was at HT Nuts house with his four 18" IXL IB in the ceiling when I heard the shotgun in Dukes of Hazard. The decay and the realism was unreal. this was something I never heard in my previous LLT setup and I don't think it had anything to do with the amount of drivers contained or any displacment advantage the IB had, the LLT system just couldn't convey that kind of detail.

This is all my opinion ofcourse but my suggestion to any considering one of these options would just be to spend the money on the drivers and put them in an IB, it's far easier then a SLLT and I'd certainly guess a good bit more realistic but it's only a guess. And plus with 30mm xmax 18" woofers now for $200 it's simply a no brainer if you ask me. Don't have enough output? Buy 8 and four behringeer or two nicer quaility higher power amps and forget anything regarding any output advantage as it will become useless.

I'm sure the SLLT has it's place in certain situations but in my limited understanding of this hobby I can't see my ever considering that route.

**SteveCallas** · **02-19-08, 07:21 PM**

Quote:

Chrisbee wrote:

Time to end these circular discussions! Time to put up or shut up!

Since you are a vociferous minority it is you who has to prove the value of your LLT design over the ever-more-popular IB.

Because an IB can't come to you it now behoves you to drag your LLT into someone's HT.

Where a typical, BFD equalised, Behringer EP2500 powered, 4 x 15" IB is installed.

(let's call this an average spec IB for the sake of this contest)

Compare the two subs side by side on the same material after careful level matching.

We'll need a couple of witnesses to ensure fair play.

Now which subwoofer sounds more real on music and film?

I'm not one to put too much into subjective opinions other than my own, but Rodny did exactly what you described - an IB to his left with two RL-p15s and a SLLT to his right ith two RL-p15s. Both started out as IBs, and both had a pretty similar FR measured at his seat. He subjectively preferred the SLLT. That's about as perfect an experiment as you are going to get.

**atledreier** · **02-20-08, 12:32 AM**

I forgot all about Rodny's little fling with IB...

I will probably build an IB, and if I don't like it will convert it to LLT, so i'll get a similar experience. Stay tuned...

**Chrisbee** · **02-20-08, 02:40 AM**

Quote:

SteveCallas wrote:

I'm not one to put too much into subjective opinions other than my own, but Rodny did exactly what you described - an IB to his left with two RL-p15s and a SLLT to his right ith two RL-p15s. Both started out as IBs, and both had a pretty similar FR measured at his seat. He subjectively preferred the SLLT. That's about as perfect an experiment as you are going to get.

I'm not talking about an extreme example. I'm talking about your Sonosub LLT.

You keep telling us it is better than any IB.

You keep badmouthing IBs as if every IB is worse than your tube and we are all wasting our time.

This may put off potential IB builders who would otherwise go ahead and enjoy very high quality bass at a very affordable price without filling their room with a huge enclosure.

It is not for us to defend our IBs. You are the only critic.

I'd be very surprised if your LLT doesn't fall flat on its face against a typical 4 x 15" IB on sound quality.

I would be very surprised if the SLLT doesn't sound shut-in, distant and very coloured in direct comparison with any IB which followed the simple rules for a successful installation.

It is long overdue that some independent ear witnesses compared the sound quality of your SLLT against a typical IB.

**WmAx** · **02-20-08, 10:50 AM**

One issue, that while being very important, seems to be rarely mentioned, concerning any speaker rigidly mounted directly to the house structure, is that usually some wall/floor structure resonances will coincide with the subwoofer's bandwidth. As a result, I do recommend that for the highest fidelity applications, that a baffle should be designed/built for these applications that has an effective suspension system de-coupling mechanically from the structure within the majority of the subwoofer's bandwidth. While this does complicate things, it appears to be not optional if the highest quality sound reproduction is desired in most instances. Of course, if the mounting wall is a concrete or cinder block wall, this is not a problem to begin with. I refer only to installations where the standard wood joisted/studded floors/ceilings/walls are used in a house for the mounting baffle.

-Chris

**NickTF** · **02-20-08, 10:53 AM**

Quote:

WmAx wrote:

One issue, that while being very important, seems to be rarely mentioned, concerning any speaker rigidly mounted directly to the house structure, is that usually some wall/floor structure resonances will coincide with the subwoofer's bandwidth. As a result, I do recommend that for the highest fidelity applications, that a baffle should be designed/built for these applications that has an effective suspension system de-coupling mechanically from the structure within the majority of the subwoofer's bandwidth. While this does complicate things, it appears to be not optional if the highest quality sound reproduction is desired in most instances. Of course, if the mounting wall is a concrete or cinder block wall, this is not a problem to begin with. I refer only to installations where the standard wood joisted/studded floors/ceilings/walls are used in a house for the mounting baffle.

-Chris

I think Thomas W recommends strictly against this. I understand completely what you're getting at but to be honest the tactile sensation is a huge benefit IMHO with these IBs. Further, because of the large displacement factor alot of these sounds are just simply going to be transmitted through sound pressure anyway.

**Sonnie** · **02-20-08, 01:19 PM**

It sounds like someone might be a tad upset that an SLLT outperformed and measured better than an IB. No reason get get so defensive Chrisbee. As far as I can tell, Steve has only provided facts provided by others who have completed measurements... not to mention Collo included a model above that shows the LLT is at least superior in extension. It appears you are merely attacking Steve. Please read again our rules about trolling and attacking members.

Quote:

Chrisbee wrote:

I'm not talking about an extreme example. I'm talking about your Sonosub LLT.

Why is Rodny's example extreme... and why is it that only Steve's LLT can be used as a comparison?

Quote:

Chrisbee wrote:

You keep badmouthing IBs as if every IB is worse than your tube and we are all wasting our time.

This may put off potential IB builders who would otherwise go ahead and enjoy very high quality bass at a very affordable price without filling their room with a huge enclosure.

He has not badmouthed IB's... he has simply stated facts.

Quote:

Chrisbee wrote:

It is not for us to defend our IBs. You are the only critic.

How can you substantiate that he is the only critic of IB subs? You cannot, so please refrain from making false statements.

Quote:

Chrisbee wrote:

I'd be very surprised if your LLT doesn't fall flat on its face against a typical 4 x 15" IB on sound quality.

I would be very surprised if the SLLT doesn't sound shut-in, distant and very coloured in direct comparison with any IB which followed the simple rules for a successful installation.

It is long overdue that some independent ear witnesses compared the sound quality of your SLLT against a typical IB.

Now who is criticizing what?

This is absolutely unsubstantiated based on previous comparisons.

Furthermore, you are attempting to discredit Rodny (who is also one of our staff members) whom I know personally to be very reputable, credible and honest. He even provided measurements to support his findings and explained the differences he heard and why he preferred the SLLT over the IB. There was nothing extreme about his IB or his SLLT.

When you make blanket comments like you have above, you also attempt to discredit SteveCallas and Ilkka (who is also a staff member), who have both proven to be credible and reputable as well as have been very helpful to our members in this forum.

I will suggest once again that you read our rules.

Advertisement