[Pinhead-227]

I was sitting in my room last night watching a movie and all of the sudden I had a question. Why not port your IB enclosures? Sounds crazy and impossible, right? But take my room for example.

My HT room is in the basement. Underneath the stairs is basically unusable space (other than storage). Why not make that entire space (measured to 132 cu. ft.) a huge ported enclosure? According to port length calculator software, a 131 cu ft enclosure tuned to 15 hz would require a very short port at "normal" port sizes. In fact, a 12" diameter port would only be 1.56 inches long. Why not use a mammoth subwoofer that can already get crazy deep (like an LMS 5400 18") and tune it to, say, 10Hz? That would need a 12" port at 14.49" or even an 18" port at 39" which would be pretty attainable...

Acoustically, what'd be wrong with such an enclosure?

 

[SteveCallas]

I pushed for such an idea for a few years. Finally Rodny tried it out, converting his quad driver IB at first to a 2 driver IB vs 2 driver LLT. He preferred the LLT. He then converted the whole thing over to a quad driver LLT and his measurements show a very nice gain in low end capability.

It is a valid idea, it works, and it offers a performance improvement. Why don't more people do it? The extra work of enclosing the backspace is a larger task than some would like to undertake. An IB is very quick and easy.

 

[Sonnie]

Ported IB? An oxymoron, no?

Just pickin'! :bigsmile:

Yeah... as Steve has stated, this is tried and proven successful by Rodny.

That is not to say it will work in every situation, but it sure makes sense that it would. It would be nice if the next person who does it will take before and after measurements to see the results and whether it is an improvement or not.

 

[Pinhead-227]

Good to know that I'm not completely crazy. :whew:

 

[atledreier]

Also, you isolate the 'P-IB' from the rest of the house pretty efficiently, which for me would be the largest benefit. Maybe that's a new term, 'PIB'?

 

[lcaillo]

The term is simply contradictory. It is no longer IB. It would be more correct to speak of a converted IB.

 

[atledreier]

Hehe! I vote for 'IBwaH', IB with a Hole...

 

[Sonnie]

The term is simply contradictory. It is no longer IB. It would be more correct to speak of a converted IB.

That's why I said "oxymoron". Rodny called his an "IB Makeover".

 

[atledreier]

BILLT - Built In LLT.... We need a fancy acronym for the configuration.

 

[Sonnie]

It already has a name... SLLT - Structural LLT.

 

[atledreier]

Ok, I give up.

 

[Mike P.]

An IB with a port is not a LLT. It's a IB with a port. Try modeling a SoundSplinter RL-p18 in a ported cabinet that is 10 times the vas of the driver. An LLT it's not.

 

[Sonnie]

If it is enclosed, then it would not be an IB would it? If it is ported, it would would also no longer be IB, would it? :scratch:

 

[SteveCallas]

The idea is not to leave it as an IB and just add a port. The idea is that if you have a ton of space to work with in an adjacent room, enclose a portion of that space so that you are able to use as much volume as you want for an ideal LLT.

 

[Mike P.]

That would make sense. An IB converted to a SLLT - Structural LLT would be a good description.

 

[DaveC]

I had friend who converted his coat closet this way. He used 2 Aura 18"s. I don't remember any more about the specifics, but with the Auras he was able to get away with very little power, and still shake the concrete front walk. He could really scare people as they were walking up to the house.