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Dorm Room System 2.0 sub suggestions? And build to follow


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Just got in the shop today at school so I should have access in a week or two. A friend's cousin lives in the area and he agreed to take me to get wood when I need to get it. I'm currently drowning in work (mid-terms are this week too, yay trimesters!) so it's gunna be a slow build for a little bit. It just hit me today that I really want to do a nice 4th order box with an aeroport and plexiglass window :) might be a little out of my league, but how else are you supposed to learn???

masterbation is free, and even saves you money.sorry but someone had to say it

sorry, Jimmy...beat you to it (no pun intended)

LOLDON'T get a wife. Best advice I never got, and now it's too late <_<

My build: 12" DCON in a dorm room.

New/current build: 8" woofer, custom amplifier block, fiberglassed speaker pods

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working on 4th order plans right now. Rockford says it'll like .23 cubes sealed and .65 ported, going to go 3:1 so .23ish cubes sealed and .7 ported. thinking about going .25 and .75 but that sounds a little bigger than this sub will like, although i have conflicting information that a bit bigger of a box helps get lower but then again 4th orders make it easy to kill subs and I'm going to be running 300watts daily on a 200rms 400max wattage sub...sketchup pics up soon!

masterbation is free, and even saves you money.sorry but someone had to say it

sorry, Jimmy...beat you to it (no pun intended)

LOLDON'T get a wife. Best advice I never got, and now it's too late <_<

My build: 12" DCON in a dorm room.

New/current build: 8" woofer, custom amplifier block, fiberglassed speaker pods

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It'll be pretty peaky at a 3:1 ratio. And I assume for a home theater system you would prefer a broad and flat response.

leap03.gif

Violet curve:

Rear volume = 2.68ft^3

Front volume = 1.05ft^3

Port tuning frequency = 52.5hz

Green curve:

Rear volume = 2.68ft^3

Front volume = 2.10ft^3

Port tuning frequency = 52.5hz

Red curve:

Rear volume = 2.68ft^3

Front volume = 4.20ft^3

Port tuning frequency = 52.5hz

As you can see all three of the enclosures are tuned at 52.5 Hz, they all contain the same driver at the same power.

But as you increase the ratio of front/rear volumes you achieve a much higher peak in the response.

Source: http://www.bcae1.com/spboxad1.htm

Also note that no two drivers will act the same way even if in the same enclosure.

These are three different drivers all in the exact same enclosure.

leap05.gif

For determining the diameter needed for the vent in a band-pass enclosure use the following equation.

Some people use it as is and some divide the tuned frequency by two before entering in the formula.

dv: Required diameter of the port in inches.

Fb: Tuning frequency of your enclosure in Hertz.

VntFrm1.gif

To determine the length of the vent use the following:

LVFormul.gif

If you want to calculate square vents, the formula below will give you the value of R to use in the formula above.

SqConvrt.gif

Source: http://www.carstereo.com/help/Articles.cfm?id=21

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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Krakin, give me a sec to go pick up the pieces of my brain which have now exploded all over my room....what program is that? holy crap I can't thank you enough for saving me the time and effort of designing that box and trying to get some enclosure software...now I'm thinking about doing just an aeroported box with the sub forward and port to the side, or both facing up (i wana be able to shake my bed a little bit every now and then). any chance you could throw some specs my way? I think I can tune to around 35hz but I want to be able to hit down to like 28hz or as low as possible with this Rockford woofer

masterbation is free, and even saves you money.sorry but someone had to say it

sorry, Jimmy...beat you to it (no pun intended)

LOLDON'T get a wife. Best advice I never got, and now it's too late <_<

My build: 12" DCON in a dorm room.

New/current build: 8" woofer, custom amplifier block, fiberglassed speaker pods

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An aero-ported what?

Band-Pass or vented?

In a vented enclosure the port determines the point of least excursion, after that it rolls off at -12db/octave.

The tuning point also helps determine where the local maximum of the response will be located, it doesn't determine it as the Thiele/Small parameters are part of the other factors.

In a band-pass enclosure the tuning helps determine the low-pass of the range of notes that will be in the pass-band.

The sealed partition is where the low end is generated. The roll-off would be -12db/octave below AND above tuning.

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

Aero-ported vented enclosure, as a bandpass enclosure doesn't look like it will give me the response results I'm looking for. And so about that 4th order enclosure that the ported section determines the bottom of the range and the sealed portion determines the top of the range? And as far a thiele-small parameters, as far as I understand those are determined by the woofer specifications, correct? Thank you for this enlightenment

masterbation is free, and even saves you money.sorry but someone had to say it

sorry, Jimmy...beat you to it (no pun intended)

LOLDON'T get a wife. Best advice I never got, and now it's too late <_<

My build: 12" DCON in a dorm room.

New/current build: 8" woofer, custom amplifier block, fiberglassed speaker pods

Link to comment
Share on other sites

And so about that 4th order enclosure that the ported section determines the bottom of the range and the sealed portion determines the top of the range?

Opposite.

The vented section filters out higher frequencies such as: 100 and over.

The sealed portion extends the low-end extension.

And as far a thiele-small parameters, as far as I understand those are determined by the woofer specifications, correct?

The Thiele/Small parameters are the woofer specifications: ie. Fs, Vas, QTC, ect..

Check out this website, it will cover the basics of almost everything in audio

www.bcae1.com

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

ooook now i got it, thanks. Damn, of all the fricken years I've spent googling shit and never found this website... thanks man much appreciated! Were those previous screenshots of the response curves tuned for the woofer I'm using? I still can't decide if I want to do a 4th order or just do a ported box with an aero

masterbation is free, and even saves you money.sorry but someone had to say it

sorry, Jimmy...beat you to it (no pun intended)

LOLDON'T get a wife. Best advice I never got, and now it's too late <_<

My build: 12" DCON in a dorm room.

New/current build: 8" woofer, custom amplifier block, fiberglassed speaker pods

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