What is an SLLT?

[SteveCallas]

Chris wrote:

Don't LLTs suffer from increased coloration over an IB due to the much smaller enclosure? If you don't believe subwoofers have coloration then I suggest you compare any other subwoofer with an IB. Manifolds are much too small for inter-panel modes to be excited by the usual passband. This is not true of LLTs.

All logic would point to this "lack of coloration" people speak of as being the result of going from a small, single driver subwoofer to using multiple drivers with more power. You can't have multiple variables change in a comparison and then expect to nail down a difference based on one thing.

Don't LLTs need a large airtight enclosure which costs far more money and work than a simple manifold. Stiffening a large LLT enclosure must be an exercise in frustration.

That's why most free standing LLTs are made of sonotube - no exercise in frustration needed. Yes, a LLT is more work than an IB, but you get more performance.

What is the phase relationship between the port and the drivers over the entire powerband? How much coloration does the large port introduce in the powerband?

Please don't go down the track about group delay, it has been covered to death at AVS between myself, Ilkka, bosso, Seaton, and others over a span of a couple years It's a non issue with the low tuning of a LLT.

I wonder whether the LLT can mange micro-dynamics like the IB?

I don't even know what that means.

Doesn't the LLT need more power to perform as well as an IB?

The opposite is true.

Does the LLT offer the same levels of distortion as an IB?

No, the LLT has less distortion.

[Blaser]

Hey Chris.... What do you have against LLTs???

[Sonnie]

He has an IB and wanted to convert it to an LLT but couldn't... he's just jealous...

[Blaser]

I wonder whether the LLT can mange micro-dynamics like the IB?

What is "micro-dynamics" How IB can mange micro-dynamics?
I prefer a sub to deliver huge dynamics Don't you?

[Chrisbee]

Microdynamics are the subtle changes in level which are essential to enjoyment of music. It is the one factor which makes things sound real.

Can you sense the leading edge, the sustain and decay of every sound you hear reproduced by your subwoofer system? Can you do so effortlessly or do you have to listen attentively?

I listen to a lot of classical organ music. The LF detail available from ordinary DVDs is often stunning if your subwoofer is up to the task. The difference in bass quality between an IB and other subwoofers I own is astonishing. The subtle interactions of the great pipes is laid completely bare. The tonal quality, attack and decay are readily heard in the briefest of notes. The real sense that the audible is built on a vast infrasonic foundation is truly remarkable.

From my own experience with a more modest, but still large tubular subwoofer, I would be very surprised if Sonotube LLT coloration was not very high. The sense of distance totally absent in the low frequencies. The sound very shut in and wholly lacking the enormous and instantaneous weight of the IB.

Only direct comparison between the two types would be a valid test. In isolation it is very difficult to judge absolute SQ until you have actually heard an IB. One might think that such low frequencies are devoid of detail and the very clear audible clues I mention. I'm afraid that at this level of bass quality it is not nearly enough just to make loud noises at particular frequencies. Low distortion and subtle dynamics are vital in bass of the highest quality. Or all you have is a rather large boombox. By sheer coincidence I was at the fairground yesterday! There were also live groups playing in the beer tents.

Rodny's LLT installation is a different case altogether. He probably has just enough of the volume and cone area to match IB sound quality. An LLT sonosub is more like a Sunfire subwoofer. I'm afraid absolute SQ requires large cone area and very low cone movement. Start thrashing the air about and distortion rises rapidly. The cone is always too busy moving to do all the subtle things which really matter. Particularly if greater reality in reproduction is required.

Objects which produce low frequencies always involve large areas, great lengths or large volumes. Or all three simultaneously. The IB makes the best stab at the proper scale of things. Infrasonics use vast components in the real world.

Try blowing across the port of any Helmholtz resonator with compressed air. You've never heard such an awful racket in your life!

[Blaser]

Chris,

You should really hear my LLts...then we can discuss You will feel (I mean feel) "100X macro vibration dynamics" as far as "micro dynamics"....don't even think about it, I promiss all your dreams will be fulfilled...too easy for them

[Chrisbee]

Without hearing them I obviously can't judge their SQ.

Though I'd like to hear what they can do on classical organ music.

As long as you're happy with yours then that's all that matters.

I'm not tempted to start building large ported boxes now when my IB manifold is already 4' x 2' x 18" and I cannot imagine better bass SQ than I have already.

I am tempted by 4 x 18" just for the fun of it but Thomas doesn't seem to think I'd gain anything except more volume.

[Blaser]

Chrisbee wrote:

Without hearing them I obviously can't judge their SQ.

I am joking with you friend, and I respect what you say

Though I'd like to hear what they can do on classical organ music.

Well I don't know myself, but maybe the LP FR might give an idea

I'm not tempted to start building large ported boxes now when my IB manifold is already 4' x 2' x 18" and I cannot imagine better bass SQ than I have already.

Yes, (IMO) that's the real disadvantage if you're not ready to sacrifice such space!!

I am tempted by 4 x 18" just for the fun of it but Thomas doesn't seem to think I'd gain anything except more volume.

Yeah... Would like to see a cool thread about that if you ever upgrade

[SteveCallas]

The problem with all the flowery descriptions of IB's is that the users are almost always going from some small single driver subwoofer to a multi driver IB. Chris, if I am not mistaken, went from a single 12" SVS to quad 15" drivers, therefore any opinions on sound quality changes can't be attributed to the IB implementation itself with any confidence, as you are overlooking the 800lb gorilla that is the change in displacement capability. Put just that single SVS 12" in an IB and then tell me how it sounds (this is of course assuming it's not bottoming every 10 seconds, which it most likely would be with bassy movies)

This is why I was so excited about the prospect of Rodny's testing, as he is the ONLY person I know who not only went from quad drivers in an IB to the same four in a LLT, but he tested two vs two in each setup. He kept two in the IB configuration and two in the LLT configuration, one set on each side of the room, both yielding a very similar FR >30hz at his seat. The main difference performance-wise was the low end capability AND less distress on the drivers in the LLT configuration, resulting in less distortion. Those differences were enough for him the favor the sound and capability of the LLT.

His is really the only such comparison that is valid. Everybody else seems to be missing the forest for the trees, trying to explain things away with audiophile-esque descriptions.

[brucek]

His is really the only such comparison that is valid

Yeah, I admit I was a bit of a sceptic, but Rodnys testing was very revealing.

He was quite cooperative with all the tests he was asked to do. He did it for the team though.

brucek