First Subwoofer completed

[HTRookie]

Here is a photo of my first subwoofer, and very first speaker project. It is basic-a Tang Band W8-740C with two Peerless 10" passive radiators, massed to 510 grams. Enclosure is 26 litres, net internal volume.

The enclosure is 1" mdf, with rabbit and dado joinery. The baffle board for the active driver has maple dowel pins epoxied in to it to secure the wood screws holding the driver in place. The PR's are secured with hurrican nuts and socket cap screws. The plate amp is from Parts Express.

I wish to thank all those that took the time to answer some very basic questions from a middle-aged novice speaker builder; special thanks to Cal Weldon for his encouragement and support.


Now, onto my REAL sub...

HT Rookie

[Lindell]

Looks cool.

What was your reason to use larger passive radiotors than actual driver?

[Dr.EM]

Nice work there, good finish

[sumsound]

With a passive radiator, you need a specific mass to tune the cab correctly, most likely a passive radiator of the same diameter would not have the appropirate mass.

Antone-

[richie00boy]

Originally posted by Lindell
What was your reason to use larger passive radiotors than actual driver?

You should always use a bigger passive radiator than the main driver.

[AKN]

Originally posted by richie00boy


You should always use a bigger passive radiator than the main driver.

Yes, depending on tuning, PR excursion can be considerably large if PR is of the same size as the driver.
Se Peerless application note for XLS12 where they had to change tuning because of PR overload.

[Cal Weldon]

That looks great Bruce,

When is the audition?

[HTRookie]

Cal,

As soon as I slightly enlarge one opening for a passive radiator (the one in the photo), because when I painted it, it was too tight- I have learned a number of lessons from this project that I will incorporate into the next one...

1). Don't try to cut the holes to aerospace precision-the drivers, be they cast or stamped will be neither perfectly concentric or exactly the same diameter.

2). Layout and machine ALL the holes for the driver screws before you paint- rather hard to see my layout marks under four coats of paint

3). Glue up over several days-I have a LOT of clamps, but only two hands ...

4). Use epoxy adhesive for everything-NOT because of its superior strength, but because it gives you a nice long open time that you need to position panels and square things up

5). Start a speaker DIY hobby at a much younger age ... I would have already have made these mistakes 20 years ago

HTR

[Lindell]

Originally posted by richie00boy


You should always use a bigger passive radiator than the main driver.

Yeah I know. But normally you use two passive radiators with the same diameter, no?
And using a weight on the radiators to tune?

[richie00boy]

You can use e.g. a 12 inch PR for a 10 inch woofer, or 2x 10 inch PR for a 10 inch woofer. There's lots of combinations, just as long as the PR displacement is more than the woofer.