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[Doug Fowler]

As Ivan mentioned regarding the SM80F LF,  it might take 2 x 12s or 15s to keep up with SM80.

Cheers
Martin

True but we’re also looking at maybe 80Hz cutoff rather than an octave lower as is the case with SM80F.

[Chris Grimshaw]

As always, it depends. Program material, crossovers, etc.
I think 2x12" running 80Hz-200Hz would do the job, but we can always double that up for more demanding applications.

Chris

[Ivan Beaver]

True but we’re also looking at maybe 80Hz cutoff rather than an octave lower as is the case with SM80F.

It does make a difference.

There are penalties to be paid in any design.

If you want to go lower (and keep the same size), you lose output.  As a "general rule for low end" there is a 9dB/oct loss in output, keeping the same size.

So on the other hand, raising the cutoff, can either increase the output, or reduce the cabinet size (for the same output).

NOTE: There are a lot of variables and specifics involved, so "general answers" can often be wrong.

And then there are other physical constraints, that can affect what design to use.

In the case of the SM80F, the entire cabinet size is used for the low end, NOT just the area where the woofers are located.  The horn goes all the way to the top and back down again.  So it would not be as simple as "chopping the cabinet into 2 pieces" for smaller/lighter pieces.  The SM80 part is just a small part of the overall cabinet internal volume.

[John Schalk]

The following PA stack puts the bottom of the SM80 at least 6' 4" high and the total stack height is 8' 6".  The THMinis are laying on their sides and you can substitute any other tall sub you want as long as it's close to 24" wide.  The TTS 56 can be low passed from 60Hz - 90Hz and the THMini is spec'd out to 200Hz.

SM80         25.5" x 24" x 12.75"
THMini       15" x 24" x 24"
THMini       15" x 24" x 24"
RCF TTS56 46" x 23.25"W x 39"D

[Rick Powell]

The following PA stack puts the bottom of the SM80 at least 6' 4" high and the total stack height is 8' 6".  The THMinis are laying on their sides and you can substitute any other tall sub you want as long as it's close to 24" wide.  The TTS 56 can be low passed from 60Hz - 90Hz and the THMini is spec'd out to 200Hz.

SM80         25.5" x 24" x 12.75"
THMini       15" x 24" x 24"
THMini       15" x 24" x 24"
RCF TTS56 46" x 23.25"W x 39"D

That's a lot of sub-division, LOL. a 5 way system. Would be interesting to hear how it sounds.

[Tim McCulloch]

That's a lot of sub-division, LOL. a 5 way system. Would be interesting to hear how it sounds.

Subdivisions worked for RUSH.

[John Schalk]

That's a lot of sub-division, LOL. a 5 way system. Would be interesting to hear how it sounds.

Well, I was thinking that it would be a two-way system with aux fed subs.  Both THMinis would be the "lows" and the SM80 would be the "highs" since, as I understand it, many SM80 owners choose to run them passive.  Mostly I was just posting the idea for fun when I saw that a THMini on its side would be the same width as an SM80. 

[Ivan Beaver]

as I understand it, many SM80 owners choose to run them passive. 

The SM80 does not have an option to run biamp, only passive.

[Scott Carneval]

What's wrong with the SM80M? I think someone mentioned it earlier in this thread. It has a -3 of 86Hz and a -10 point of 70Hz.

Or you could frankenstein your own, kinda like this 'OS80F' we came up with a couple days ago...or should we call it 'OS1180XL'?

[Rick Powell]

What's wrong with the SM80M? I think someone mentioned it earlier in this thread. It has a -3 of 86Hz and a -10 point of 70Hz.

Plus, unlike its cousin the SM80, it is switchable to be either passive or bi-ampable if you want to run it that way.

[ProSoundWeb Community]