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8th order design challenge


KiKaZz74

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Any of the iso boxes look badass I think. Dont gain anything with them really tho.

My SPL to SQ Build Log

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Sub Amp- Hifonics BRZ1700.1D @ 2 Ohms Taramps DSP3000.1D

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8 ~ XS Power XP3000

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The "order" of a box actually refers to the rolloff. It has nothing to do with the alignment really. Like a 4th order crossover rolls off at 24db per octave, a "4th order bandpass" rolls off at 12db per octave below tuning AND above (hence the 4th order designation). Just as an aside... a regular ol' ported box is actually a 4th order.

A 4th is more accurately a "single reflex bandpass".

The box pictured is just a aperiodic bi-chamber. It's not really an "8th order". And ABC's aren't any bigger than a standard vented. They're just parallel tuned in octaves.

And 8th would be like a "6th order" inside of a 4th order. And yes... it would be hyooooooj.

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Can anyone tell me....What does the "8th" in 8th order mean? What does the "order" in 8th order mean?

Taylor beat me so if his is better (most likely is) use his.

A fourth order has a sealed back chamber with a vented front.

4thordbp.gif

A sixth order has rear vented and front vented chambers.

6thordbp.gif

An eighth order has three chambers. All three are vented. With the front and rear chambers of the sixth order vented into another chamber.

8tripbp.gif

b_350_20_692108_381007_FFFFFF_000000.png

Krakin's Home Dipole Project

http://www.stevemeadedesigns.com/board/topic/186153-krakins-dipole-project-new-reciever-in-rockford-science/#entry2772370

Krakin, are you some sort of mad scientist?

I would have replied earlier, but I was measuring the output of my amp with a yardstick . . .

What you hear is not the air pressure variation in itself

but what has drawn your attention

in the two streams of superimposed air pressure variations at your eardrums

An acoustic event has dimensions of Time, Tone, Loudness and Space

Everyone learns to render the 3-dimensional localization of sound based on the individual shape of their ears,

thus no formula can achieve a definite effect for every listener.

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Yes, I do know that a 4th order is a ported box. I didn't realize it was because of the rolloff slope. I don't think people understand that, then. Why would anyone want a subwoofer with an 8th order rolloff slope? Just for SPL competition? if you had no subsonic filter, maybe that would be handy. But any amp today has a subsonic filter. My personal choice is to extend low frequencies as far below tuning as possible without over excursion or unloading of sub.

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Yes, I do know that a 4th order is a ported box. I didn't realize it was because of the rolloff slope. I don't think people understand that, then. Why would anyone want a subwoofer with an 8th order rolloff slope? Just for SPL competition? if you had no subsonic filter, maybe that would be handy. But any amp today has a subsonic filter. My personal choice is to extend low frequencies as far below tuning as possible without over excursion or unloading of sub.

An "8th order" would have a retardedly small bandwidth but have enormous gain/efficiency. If you could do it right, it'd be an SPL monster.

Incidentally... if you also add a crossover to your 4th order (or whatever) you add an order. Add a 2nd order crossover to your ported box and voila'... you now have a 6th order and you're cool.

An 8th order's rolloff would be 24db above and below tuning. Not 48db either way.. LIke... a 6th is 24db per octave below tuning but only 12db above tuning.

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I been looking at the Bose Acoustimass design and from what I can see this is the outcome.

with Qts=.42, Vas=.46 ft^3, Fs=56
you should get

V1= .68 ft^3 Fb1=78.85 Hz
V2= .35 ft^3 Fb2=39.77 Hz
V3= 2.98 ft^3 Fb3=Fs=56 Hz

F3Lower= 36 Hz
F3Upper= 87 Hz
bandwidth= 51 Hz

b_350_20_692108_381007_FFFFFF_000000.png

Krakin's Home Dipole Project

http://www.stevemeadedesigns.com/board/topic/186153-krakins-dipole-project-new-reciever-in-rockford-science/#entry2772370

Krakin, are you some sort of mad scientist?

I would have replied earlier, but I was measuring the output of my amp with a yardstick . . .

What you hear is not the air pressure variation in itself

but what has drawn your attention

in the two streams of superimposed air pressure variations at your eardrums

An acoustic event has dimensions of Time, Tone, Loudness and Space

Everyone learns to render the 3-dimensional localization of sound based on the individual shape of their ears,

thus no formula can achieve a definite effect for every listener.

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Share on other sites

I been looking at the Bose Acoustimass design and from what I can see this is the outcome.

with Qts=.42, Vas=.46 ft^3, Fs=56

you should get

V1= .68 ft^3 Fb1=78.85 Hz

V2= .35 ft^3 Fb2=39.77 Hz

V3= 2.98 ft^3 Fb3=Fs=56 Hz

F3Lower= 36 Hz

F3Upper= 87 Hz

bandwidth= 51 Hz

That's all well and good... but can you extrapolate the calculations?

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