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Author Topic: LAB subwoofer plans  (Read 1271 times)

Ivan Beaver

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Re: LAB subwoofer plans
« Reply #10 on: October 13, 2020, 12:17:00 pm »

Possible alternative for you, that has even more extension than the LAB Sub and can be built in 2 smaller more portable cabs.

https://billfitzmaurice.info/T60.html


I don't know about the particulars of the suggested build, but I have seen a number of graphs on that site (as used for comparisons) be wrong.  So they are not as close as the graph would suggest.

But they might be right.  I don't know
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Ivan Beaver
Danley Sound Labs

PHYSICS- NOT FADS!

Mark Wilkinson

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Re: LAB subwoofer plans
« Reply #11 on: October 13, 2020, 01:40:20 pm »

????

Hi Doug,

Labhorns's impedance head south after about 90-95Hz, and don't raise much above minimum from there on.
Attached graph is a single box.

Back when there was a lot of folks building them, i recall reports of folks having coils open. And then subsequent talk about small rear chambers and their contribution to heat build up.

So I figure it makes sense to minimize heat from any content above 100Hz, if possible.


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Caleb Dueck

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Re: LAB subwoofer plans
« Reply #12 on: October 13, 2020, 03:04:05 pm »

The DXF files didn't download correctly, but the PDF's did.  I imported then into AutoCAD LT and scaled them, so if anyone needs a DWG file - let me know. 
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Helge A Bentsen

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Re: LAB subwoofer plans
« Reply #13 on: October 13, 2020, 05:00:48 pm »

Reading this thread made me miss my Labsubs, I really liked them.
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Nathan Riddle

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Re: LAB subwoofer plans
« Reply #14 on: October 14, 2020, 02:54:39 pm »

The DXF files didn't download correctly, but the PDF's did.  I imported then into AutoCAD LT and scaled them, so if anyone needs a DWG file - let me know.

Where's the dang like button :)
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Ivan Beaver

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Re: LAB subwoofer plans
« Reply #15 on: October 14, 2020, 03:05:49 pm »



Back when there was a lot of folks building them, i recall reports of folks having coils open. And then subsequent talk about small rear chambers and their contribution to heat build up.


During the "era of lab sub building", Eminance had an issue with one of their UV curing stations.  So some of the coils did not get the adhesive properly cured, which resulted in the coils basically falling off of the former and getting trashed.

So basically the drivers did not meet specs, but it was not because of the design, but rather the manufacturing process.

It has happened to others.  Peavey got ahold of some bad adhesive they used on the scorpion drivers spiders back in the early 90s.  The glue would just break free, nice and clean and then the driver would sound bad and beat itself to death.  This happened to several thousand drivers.

B&C got ahold of some bad magnet slurry about 15 years ago.  The creamic magnets would just crack and shear in half, freezing up the driver.  Even on drivers that were not moved around (in an install) and not pushed hard.

Stuff happens.
« Last Edit: October 15, 2020, 08:51:24 am by Ivan Beaver »
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A complex question is easily answered by a simple-easy to understand WRONG answer!

Ivan Beaver
Danley Sound Labs

PHYSICS- NOT FADS!

Doug Fowler

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Re: LAB subwoofer plans
« Reply #16 on: October 14, 2020, 03:24:08 pm »

Hi Doug,

Labhorns's impedance head south after about 90-95Hz, and don't raise much above minimum from there on.
Attached graph is a single box.

Back when there was a lot of folks building them, i recall reports of folks having coils open. And then subsequent talk about small rear chambers and their contribution to heat build up.

So I figure it makes sense to minimize heat from any content above 100Hz, if possible.

Gotcha, thanks. 
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Jim McKeveny

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Re: LAB subwoofer plans
« Reply #17 on: November 16, 2020, 01:49:03 pm »

Arjun,

The LAB horn is difficult  to build, and the performance of the LAB 12 driver is rather limited compared to what is available presently.
Using 18" drivers with more Xmax (excursion) Bl (motor strength)  and power handling allows for 6dB or more output in the same footprint.

If you like FLH (Front Loaded Horn) cabinets, the design below using BC 18SW115 drivers may be a better, as in louder, cleaner and more simple to build choice, the same size (45"x45"x22.5") as the LABhorn.

Only one side is illustrated, the other is symmetrical. Center mouth bracing should be added as shown in red, didn't get the sizes down when originally drawn about 6 years ago.

Art

This is quite clever, Art! Can you give some insight into the angle iron detail?
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Art Welter

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Re: LAB subwoofer plans
« Reply #18 on: November 17, 2020, 04:35:53 pm »

This is quite clever, Art! Can you give some insight into the angle iron detail?
Jim,

IIRC, the use of angle iron and flat iron (or aluminum) for the speaker access panel door frame was a copy of a similar design using 21" drivers that would have had clearance issues if using 3/4" plywood cleats.

For this 18" design, 3/4" x 1"& 2" cleats with t-nuts would probably be my build choice.

Art
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Re: LAB subwoofer plans
« Reply #18 on: November 17, 2020, 04:35:53 pm »


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