IB vs Sealed...

[aceinc]

At what point does a large sealed enclosure become equivalent to an infinite baffle?

Can I use a sealed and sound proofed closet? What size?

I suspect the answer depends on the capabilities & quantities of drivers, but I was hoping for some rule of thumb.

Paul

[Geoff St. Germain]

The rule of thumb I've seen is between 10 and 100 times the Vas value of the driver (or sum of the drivers). You could use a closet, depending on the size of the closet and the Vas of the chosen driver(s).

[Bob_99]

I believe that over on the Cult forum they specify 4 to 10 the total Vas value (all the drivers). I've not seen the 100 times recomendation before but then again I'm still low on the learning curve when it comes to DIY subs.

Bob

[Geoff St. Germain]

There was a discussion on AVS recently (more of an argument) with some of the guys from the cult on it. They were saying 10 times, 25 times and even 100 times. From modeling the difference between 10 time and 100 times doesn't appear very noticeable.

[a1161979]

Geoff St. Germain wrote:

There was a discussion on AVS recently (more of an argument) with some of the guys from the cult on it. They were saying 10 times, 25 times and even 100 times. From modeling the difference between 10 time and 100 times doesn't appear very noticeable.

I have read on the cult to model an IB in 10,000L not sure if this helps Surely in application the difference between 25X and 50X and so on wouldnt be boticeable after EQ or maybe even before, in fact all i can see if affecting is power handling

[bonehead848]

I believe that over on the Cult forum they specify 4 to 10 the total Vas value (all the drivers). I've not seen the 100 times recomendation before but then again I'm still low on the learning curve when it comes to DIY subs.

Bob

That is what I also heard. 4 is given as the absolute minimum value.

[aceinc]

So a driver with a .95 cu ft vas would want a sealed box that's about 26" on a side, if it were a cube. Basically about 10 cubic feet.

The driver that has that vas is the titanic 10". The question then becomes how would that driver in an IB compare to other configurations such as ported, or LLT, etc.?

This is more of an intellectual exercise, as I will not be building another sub for a while. But I have a pair of the titanic 10" drivers, that may be part of that endeavour.

Paul

[SteveCallas]

An IB is just a large sealed sub, and therefore porting still has many advantages over it - namely better FR linearity into lower frequencies, lower distortion, and greater headroom.

[a1161979]

SteveCallas wrote:

An IB is just a large sealed sub, and therefore porting still has many advantages over it - namely better FR linearity into lower frequencies, lower distortion, and greater headroom.

As well as disadvantages such as larger box size's, lower power handling and higher group delay

[SteveCallas]

A LLT will have much better power handling than an IB, and it will achieve greater output levels with the same amount of power vs an IB. Increases in group delay below 20hz that remain less than one cycle are inconsequential.

[Warmon]

aceinc wrote:

This is more of an intellectual exercise, as I will not be building another sub for a while. But I have a pair of the titanic 10" drivers, that may be part of that endeavour.

Sounds like an interesting experiment. Keep us posted...

[a1161979]

SteveCallas wrote:

A LLT will have much better power handling than an IB, and it will achieve greater output levels with the same amount of power vs an IB. Increases in group delay below 20hz that remain less than one cycle are inconsequential.

What about port resonance steve

[SteveCallas]

What about it? With a typical 4th order 80hz crossover, the signal to the sub is reduced enough at the recommended minimally safe first resonance frequencies that it becomes inconsequential.

[jagman]

A properly placed IB may or may not need more EQ than an LLT. An LLT has extra output in the low end, but has group delay. Saying the effect below 20Hz is minimal doesn't mean much to me since the sub is crossed over at 80Hz. Most people who've heard IBs seem to think the sound is very clean and that things just sound real. Most who've heard LLTs seem to think the sound is more powerful. The issue with IBs is you need more driver displacement to reach equal SPL when compared to LLTs, but you need less power. This means IBs tend to be more expensive (potentially a lot more expensive). The biggest practical concerns with IBs are where to put them (difficult to test) and actually mounting the drivers in your wall/floor/ceiling. With LLT's, the biggest practical concern is locating the beastly enclosures in your room. Like most things in life, both options are good when done right, it just depends what type of sound you personally favor and what works for your room (or what your SO will allow ).

[penngray]

I have twin TC2K 15" ported subs (11 cf, 8" port, just finished recently) and I have an IB array (4 Q18s).

It takes less power to power my IB to High SPL levels then it does to power my LLTs.

My LLTs are tuned to 16 Hz, my IB can hit under 10 Hz easily.

My LLT build took a lot more wood (almost $200), lot more teadious effort, rounding sanding and so on, about 5x the amount of time.....IB array, $50, 4 routed holes, extra bracing in the attic best Sub system I own.



BTW, This thread asked about Sealed vs IB but Steve always has to chime in with his LLT stuff...its like he needs to convince himself daily that his design are better....blah...No one wants HUGE SILOs!!! They are so 80s!

[Jason Schultz]

Penngray said

penngray wrote:

I have twin TC2K 15" ported subs (11 cf, 8" port, just finished recently) and I have an IB array (4 Q18s).

It takes less power to power my IB to High SPL levels then it does to power my LLTs.

I'm sure it does take less power to make 4 18 inch subs produce a givern spl when compared to 2x 15's.

[SteveCallas]

penngray wrote:

BTW, This thread asked about Sealed vs IB but Steve always has to chime in with his LLT stuff...its like he needs to convince himself daily that his design are better....blah...No one wants HUGE SILOs!!! They are so 80s!

Back off pal, in the post before mine it was asked:

The question then becomes how would that driver in an IB compare to other configurations such as ported, or LLT, etc.?

I answered his question.

[Blaser]

Guys.... Let's keep this thread clean pls