12 fi Q sealed enclosure specs help

[zcradic 0]

Whats up,

Can anyone give me advice on how many cubes my sealed enclosure should be and what it should it be tuned to?

I will give it hopefully 1300 rms with a hif1606d.

I listen to about 80 % rock/classic rock/metal/blues/acoustic live chit and about 20% rap but I will probably listen to more rap since I will have a sub.

The sub needs to play 80hz and below. My goal is pure sq not spl

Thanks for any input

Captain SSD(lol and its gonna be a q)

[appleyard 0]

Err... you are aiming for pure SQ but you feed it with 1300w rms???

Maybe you can go with the recommended of 1.5 cu ft.

[atsaubrey 1]

Err... you are aiming for pure SQ but you feed it with 1300w rms???

Maybe you can go with the recommended of 1.5 cu ft.

1.36 cubic feet nets you 1.2 after sub dispalcement. sealed of course. As far as tuning a sealed enclousure, there is int a way to tune it per say, tuning it refers to porting the box. Go sealed and with that much power you will grin.

[theabunai 3]

He can tune a sealed enclosure by using a QTC formula

that will give you the FC (selaed enclosure tuning)

A QTC of .707 will usually yield the smoothest response around 42-43hz

If you raise or lower the QTC you can have a peaky sealed enclosure that has a targeted FC...

example the Q 12 with a QTC of .707 will give you the following results

f3 = 43.55 Hz

fb = 43.54 Hz

Where with the same sub but with a QTC of .9 will yield this

f3 = 45.98 Hz

fb = 55.43 Hz

and a QTC of .5 yields this

f3 = 47.85 Hz

fb = 30.8 Hz

Edited May 10, 2007 by theabunai

[zcradic 0]

Thanks a bunch for the replies everyone.

I see the fi guy prefers the q sealed to be 1.2-1.3 so I was just figuring I would go with that but was wondering if that should change since im giving it 1300 rms or if thats about right.

And to theabunai, Ive heard the term peaky thrown around but im not really to sure on exactly what it means on how the box sounds. I basically want it to play the whole bass range with good sound quality so should I even tune it? I know people always tune ported boxes low but I guess thats kinda different.

[theabunai 3]

Peaky means that one frequency is louder and isolated to play louder the rest of the range...

lets say you have your box tuned at 35hz

Say you play a range of tones between 20 - 60 hz and it started at 60 and went down to 20...

the sound would start off soft then increase as it reached 50hz and a little more when it reaches 40 hz then be at it's loudest at 35hz then start to get soft again as it approached 20hz... (pure example not real world or accurate results nor does it take into account EQ or Cross over effects on the range)....

A lot of people that look for a "smooth" roll off with little peak will swear by sealed enclosures....

Using a QTC of .707 (as you can see) will yield IMO one of the smoothest rolloffs...

f3 = 43.55 Hz

fb = 43.54 Hz

really tells the story

fb is Enclosure resonance

f3 is -3 dB cutoff frequency

so at -3dB the frequency only sloped .01 which tells you that it is a pretty slow decline from fb to the f3 this indicates a smooth gradual roll off...

IMO for the wattage you have

i would get a Q with BP option to easily handle that 1300rms...

Have the enclosure between 1.2-1.3 as others mentioned.... (i'd go 1.2 imo)

Get the BP option it will help with cooling the sub since in a sealed environment... the sub actually tends to work extra harder to cool off (not like the hot air has a lovely port to escape from)...

the Q is a great SQ sub that ironically can bolt out some really low notes....

When in doubt, consult the experts (Scott, Nick and shawn)

they know their product better than anyone else....

If they say for your application do this... trust them, they would never steer you wrong....

Edited May 10, 2007 by theabunai

[zcradic 0]

Awesome, thanks alot for explaining what that means, I now understand.

Is there anywhere plans for a box like this are available? I just need to know which size to cut the wood.

Edited May 10, 2007 by Captain shitstains deluxe

[zcradic 0]

So if I understand correctly, the qtc is determined by the sub specs and volume of the box.

So if thats right what size in cubic ft gives an enclosure with a fi q in it a .707 qtc?

[theabunai 3]

http://www.lalena.com/Audio/Calculator/Box/

Watch the Metric and standards variables (cubic ft vs Liters)

Here is a conversion calculator

http://www.mhsoft.nl/conv1.htm

I believe it's about 1.1 per sub

[zcradic 0]

Ok, can someone answer me this simple question:

The Q's mounting depth is 7 inches.

Is that the total depth needed? If not then what is the total depth needed for the woofer to breath normally?

[zcradic 0]

Actually I just used AJ box designer and it gave me these dimmensions:

L 12.4401

W 20.153

D 7.67909

Im guessing those are internal dimmensions so is 7.67 ok?

[theabunai 3]

sure 7.67 should be fine (id' go 8 and hand off the .33 to one of the other dimensions)

if not it should be fine since the final mounting depth will have 3/4" (.75) added to the 7.67 since the sub sits on the front baffle

[zcradic 0]

NICE! Sounds good and thanks for the quick reply and all the other answers.