Vented enclosure

Hey guy's,

I am working on modeling up a vented enclosure for My MZS1004's. The problem is, If I go by MTX's specs, the box will be way to long. I have tryed a few configurations but , am running into a bit of trouble.

The box can be a max of 34" long and 14" high, would like to keep the depth under 18".

MTX calls for 1.45ft^3 for size and a 2" x 12"  vent. Help Me Please!!!!!!!!!!!!!!! :errr:

Here is a current drawing that I whipped together using MTX's spec's.

Chris

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Alpine CDA-9833 HU
Diamond Audio M661 Components
MTX Thunder T6.6 Components:rear fill:
Cadence Q400 4 Channel Mains + rears
Thunder 801D Subs
MTX 1004 10's
Dual 4g wire to rear
4g grounds

You should have just enough room if each sub wants 1.5 ft.  What's a slotted vent with two dimensions, racer?  What we should have instead is desired tuning frequency, not the size recommendation.

Try this method:  Use half your available space for each sub...so figure max 17 X 14 X 18.  Deduct another baffle thickness from width for the center divider.  Figure that with the volume calculator and put in the baffle thickness.    Now you got cubic feet per sub to work with.  Subtract one sub displacement, and any braces you will use.  Now you have volume for one sub, which the port will take up some of.

Go to port calculator:  https://www.carstereo.com/help2/Articles.cfm?id=31

Figure dimensions for a slotted port using the volume you came up with just now and the desired tuning frequency.  The port will take up some of that space, so figure the port displacement using the volume calculator again.  Figure it as a solid object, meaning that both the air and the port wall are combined as one solid object that will take up volume in the box.  W X H X D of the port is needed.  You will now have cu. ft. of port displacement....subtract that from the total box volume that you arrived at for one sub.

Now is when you start playing this calculator over and over using smaller volumes and the same tuning frequency until you verify that you have both enough air for the sub and the right volume for the tuning freq. based on that exact amount of air.

Whew!

Once done, the other side of the enclosure will be a mirror image.

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Build the box so that it performs well in the worst case scenario and, in return, it will reward you at all times.

Forgive me for my ignorance as to vented enclosures Stevdart. This is my first attemp at building my own vented enclosure and it is only for testing and comparison. I have some free time on my hands and I need to dive into something, well, this is it.

All I did with this so far was to take the exact drawing dimensions that MTX gives for their optimum vented enclosure and mirror imaged them.

https://www.mtx.com/caraudio/products/subwoofers/TechData_MZS1004.pdf

scroll down to page 3. So using these specs is no good?

Chris

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Alpine CDA-9833 HU
Diamond Audio M661 Components
MTX Thunder T6.6 Components:rear fill:
Cadence Q400 4 Channel Mains + rears
Thunder 801D Subs
MTX 1004 10's
Dual 4g wire to rear
4g grounds

And don't mind the drawing. I am a machinist by trade and deal with cad systems on a daily basis so, I have a tendency to draw out all of the demnsions that I can to assist in the machining or construction of whatever I am drawing.

Chris

-------------
Alpine CDA-9833 HU
Diamond Audio M661 Components
MTX Thunder T6.6 Components:rear fill:
Cadence Q400 4 Channel Mains + rears
Thunder 801D Subs
MTX 1004 10's
Dual 4g wire to rear
4g grounds

Uh, didn't you say in the first post "The problem is, If I go by MTX's specs, the box will be way to long" ?  I suggest using the method I described.  All you need from MTX is sub displacement, desired tuning frequency and desired volume per sub.  You have to work it up given the space YOU have available.

And oh, I don't mind the drawing!  It looks really good.

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Build the box so that it performs well in the worst case scenario and, in return, it will reward you at all times.

Ok Stevdart,

I will play around with it as you suggested. Maybe tomorrow. Been a long day. I hear my bed calling! LOL

Chris

-------------
Alpine CDA-9833 HU
Diamond Audio M661 Components
MTX Thunder T6.6 Components:rear fill:
Cadence Q400 4 Channel Mains + rears
Thunder 801D Subs
MTX 1004 10's
Dual 4g wire to rear
4g grounds

One more question. Does it really matter where the vent is placed? I did notice that MTX's Sledgehammer multiple woofer enclosures (for the 10's at least) have the vents at the bottom of the enclosure. Some have them on either side of the enclosure or in the middle of the enclosure.

https://www.mtx.com/caraudio/products/enclosures/sledgeHammer.cfm

-------------
Alpine CDA-9833 HU
Diamond Audio M661 Components
MTX Thunder T6.6 Components:rear fill:
Cadence Q400 4 Channel Mains + rears
Thunder 801D Subs
MTX 1004 10's
Dual 4g wire to rear
4g grounds

just cuz I'm up I'll regurgitate stuff I've asked here before:

No, the vent location does not make any different provided:
a) The exit of both ends of the port has some space to breath (distance=to the diameter of the port.. maybe for your slot ports the mean of the length/width? stevdart, DYohn, anyone?) and
b)it is best to keep the woofer cone and the port exit on the the same plain as they work together to produce sound..

racer427: Try modeling ur box with WinISD and play around with different port sizes and diameters.. you might find a different size port is easily doable in your box if you ignore those slot-port and tuning frequency recommendations. I've found the best looking response curve is often far from the manfacturers spec box...   I also have it on good authority that the shape of the port doesn't have a thing to do with the sound.. so going with a 3 or 4" round port might be just what you need to get stuff done.


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"I'm finished!" - Daniel Plainview