FAST-ish enclosure help.

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can i please get some help in how you would design the enclosures for the below drivers so they would work with an active-XO fast style set-up.

I have hauled the bass units from the T-TQWT towers i made a while ago to try a FAST style set-up as a plan B if my next attempt at a BLH for the 8inch driver doesn't give me something i like.

2x 8 inch full range units.
Fs - 58hz
Re - 7.6
Bl - 12.23
Sd - 216
Vas - 36.755
Qed - 0.25
Qmd - 2.97
Qtd - 0.231

4x 12 inch woofer units (need to double check params as they're crappy)
Fs - 37hz
Re - 7
Bl - 19.4
Sd - 520
Vas - 69
Qed - 0.44
Qmd - 5.28
Qtd - 0.406

thanks for your help :)
 
ok, rephrase the question.

the box is going to have 2 chambers(?) each tuned differently. in terms of a mechanical crossover between them, do i design the FR's box first, then match the 'bass' box to try and crossover, or do i design the 'bass' first then try and match the FR to it?
 
the box is going to have 2 chambers(?) each tuned differently. in terms of a mechanical crossover between them, do i design the FR's box first, then match the 'bass' box to try and crossover, or do i design the 'bass' first then try and match the FR to it?

This will require the lower one to be a band-pass and the other a sealed or TL alignment.

Hmm, do you build a roof or foundation first?

GM
 
which is considered the foundation? the Fullrange unit or the bass units? I had assumed the FR unit, as the concept of FAST is 'full range assisted'.

also if i may further pick your knowledge; i've seen Planet10's FAST system's with side mounted woofers, can this work with any woofer and design? infact, could the woofers be mounted on the back of the box? what are the major differences in the sound produced when mounting front facing, side facing, rear facing?

thanks again for your help :)

edit: ignore rear mounted, just simulated it with MJK and its not pretty.
 
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I do understand that, I'm not entirely sure how this fits in with my question tho, sorry.

It doesn't seem so since the fundamental [low] frequency is the 'foundation' of all sound.

Historically then, the bass BW reproducer is designed first, then the mids, HF. If a true sub system is used, then this is the foundation.

That said, I keep forgetting that around here the wide BW driver is typically chosen first, then any bass, HF augmentation is tacked on.

Fortunately, the woofer, [super] tweeter selection is so large nowadays that given time one should be able to find a close enough fit or at least one that can be blended with a custom XO that now can be easily designed using either software or adjustable digital XO.

GM
 
i've seen Planet10's FAST system's with side mounted woofers, can this work with any woofer and design?

Ideally only if the woofer acoustical center are < 1/4 WL away from the XO's -12 dB point, so the higher the slope order, the greater the mounting gap can be.

Since our hearing acuity dramatically degrades down low, many folks can tolerate up to 1 WL away, so it depends on the person's hearing and the room's acoustical conditions that will set the max acceptable offset.

GM
 
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