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Old 4th November 2011, 02:48 AM   #1
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Default Need the plans for a Bose 502b or MB12

I have a pair of Bose 144392 12 inch 400w 4inch voice coil subs in excellent condition. I'd like to throw them in a sub box for either my e-drum rig or a small pa. They are either out of the 502B panarays or the MB12 cabs. Does anyone have the plans for those or maybe have a 502b they could measure the inside of?
I seriously doubt Bose will supply the TS params or the cabinets even though they are discontinued. If someone has build a good box for them that would do as well. I'd hate to trash em or stick them in useless cabs in this economy. Cheers
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Old 4th November 2011, 08:55 AM   #2
dangus is offline dangus  Canada
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It's not that hard to measure T-S parameters. Even when drivers come with spec sheets, it's a good idea to measure them before making sawdust. The Woofer Tester is probably the easiest way to go. There's other software that uses the sound card to generate test signals and take measurements. Speaker Workshop is one. Maybe there's another DIYer near you who is already set up to measure T-S and would help in exchange for pizza and beer.
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Old 4th November 2011, 07:15 PM   #3
dangus is offline dangus  Canada
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A rough idea of box volume can be had from the MB12 specs. And since an impedance plot is provided, you could determine the port frequency. Print out the image as large as possible, then find the frequencies of the two peaks by interpolation.

They don't seem like a great choice for a PA unless you're talking really small events or background music. Maybe they're suited to horns. I'd be tempted to use them in the car or van. They go nice and deep and should handle stupid amounts of power.
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Old 4th November 2011, 08:35 PM   #4
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From what I can tell the MB12 is a transmission line box. Not sure how to figure out the volume from that. The 502b was a bandpass box, I have the external size but not the ports or internal slanted divider. I figured since the TS params will probably not be forthcoming (I emailed Bose), I simply copy one of thier cabs.
They are to be used on stage as part of my electric drum rig and possibly for a small PA under a pair of 12+horns with NO Budget. I could certainly toss them in the bottom of a 4x12 or in some crap cabinet but then that would probably be a waste. I even thought about guessing at the center divider/baffle but I'd need the port sizes.
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Old 6th November 2011, 11:19 PM   #5
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http://sound.westhost.com/tsp.htm

measure the T/S parameters.
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Old 7th November 2011, 06:48 AM   #6
dangus is offline dangus  Canada
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The impedance plot of the MB12 looks like a conventional ported box (two peaks).
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Old 6th December 2011, 10:54 PM   #7
OscarS is offline OscarS  United States
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I have a couple of these that I'm about to recone, and I have the Woofer Tester3 from Parts Express. I'll measure them after I recone them and post back.
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Old 24th December 2011, 01:13 AM   #8
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Quote:
Originally Posted by screamersusa View Post
I have a pair of Bose 144392 12 inch 400w 4inch voice coil subs in excellent condition. I'd like to throw them in a sub box for either my e-drum rig or a small pa. They are either out of the 502B panarays or the MB12 cabs. Does anyone have the plans for those or maybe have a 502b they could measure the inside of?
I seriously doubt Bose will supply the TS params or the cabinets even though they are discontinued. If someone has build a good box for them that would do as well. I'd hate to trash em or stick them in useless cabs in this economy. Cheers
How about selling them,
I will get them from you for the right price
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Old 28th January 2012, 08:28 PM   #9
OscarS is offline OscarS  United States
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I promised parameters, and I'm close to delivering. Finally got the time to recone mine. I'm using this kit:

Speaker Exchange | Bose 502B 12″ Aftermarket Recone Kit
Click the image to open in full size.


The frame on this speaker is not too friendly for reconing without a preassembled kit because you can't see the top plate/pole piece intersection. This prevents you from seeing the windings above the plane of the top plate to set the voice coil properly:

Click the image to open in full size.


so I used a second identical coil beside it with notebook paper to see how high the coil needs to be, to be centered abouts the top plate:

Click the image to open in full size.


This way, I used a flat solid object to align the coil that was actually placed in the speaker to be reconed, to the height of the coil that was on top of the paper, and scribed a line on the shim plastic to use as a guide for the second 12":

Click the image to open in full size.


Now I'm just waiting for the CA to cure to set the rest of the parts in place:

Click the image to open in full size.
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Old 30th January 2012, 01:16 AM   #10
OscarS is offline OscarS  United States
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done. Just have to get some nice terminals, and an extra pair of felt dustcaps (I doubled-up the two I had with a layer of polyurethane glue between then to get them nice and stiff).

Click the image to open in full size.

Click the image to open in full size.

Preliminary check of parameters don't look too good (for my personal preference):

Click the image to open in full size.


I like most of my woofers with sub-0.30 Qts, and this won't get there even after break-in. Galaxi15, you still interested in a pair of these?

Last edited by OscarS; 30th January 2012 at 01:23 AM.
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