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Bob's 184 Subs
















Here are some pics of the 184 subs I built in various stages of construction.

I used Fane 18XB drivers and have found them to sound very good (obviously I don't have the PDs or RCFs to compare them to)

Here is some advice I would give to anyone thinking of building these subs:

1) Cutting the circles for the port tubes was a bit hit and miss - cutting such a tight radius with a jigsaw tends to bend the blade, giving the cut a slanted finish, and making sealing the gap more difficult.

2) Screwing the port tubes to the front panel was a bitch - we ended up driving nails in, then taking them out and putting a screw into the resulting hole.

3) Get the plywood cut by someone else with a wall saw - we got ours done for 50 pence per cut at the B&Q warehouse, and all of the cuts were spot on - within a millimeter - and this makes putting them together so much easier

4) Put some handles in them - they're rather heavy to move around when built, so taking some time to fit handles (or making your own) would be time well spent - I'll definitely be fitting some on the next cabs I build

Apart from that they were very easy to build - just have to follow the rule of measure twice and cut once.

Thank you for these excellent designs, I can only wish that there were more PA sites that had plans of this quality on.

Bob G


Rog's Reply:

Thanks Bob for those tips, just a quick word of how I go about points 1 and 2.

I always cut the 6Ē holes in the baffle with a router fitted with a straight cutting bit and radius attachment. Even when I used to use a jigsaw for cutting the holes I never found it difficult and never had the problem of the blade slanting. I think the use of a better more professional jigsaw and cutting more slowly would help here.

I have never screwed ports onto a front baffle. There are two ways to attach the ports to the baffle, the first way is to always make the baffle holes a very tight fit and use lots of grip fill (builders construction adhesive) to hold the ports on to the baffle. Always leave around 2 mm of port just proud of the baffle and then use a belt sander to sand them down flush with the baffle. The second and better way is to attach the ports to the baffle is to make the hole for the port in the baffle smaller than the port, then use a router on the back of the baffle to route out a channel the same size as the external diameter of the port. The channel should be around 14 mm in depth, so that it does not break though to the front of the baffle. Use lots of adhesive Ďgrip fillí and push the port tightly into the 14 mm deep channel on the back of the baffle. Now use a trimming bit in your router on the front of the baffle to make the hole as seen from the front of the cabinet the same diameter as in inside of the port. A trimming bit is a straight cutting bit with a bearing at one end, make sure the bearing is touching the inside of the port as you go around it, that way the hole will always be the same size as the port. Lastly use a round over bit to put a radius on the baffle hole. Fitting the ports this way will always make sure that the hole you see from the front of the cabinet is the same size and shape as the inside diameter of the port.

The last point I would like to make is that I never use any battens around joints. If you use lots of glue and screw every 150 mm then I donít think that adding battens makes the cabinet any more air tight or last longer on the road. It just adds weight and takes up internal volume. I would rather the cabinet be really well braced from adjacent and opposing panels than be battened just around the edge of the box. And if you do use bracing donít put it exactly half way along or in the middle of a panel, always offset the brace, as if you divide the panel into two equal sections you now have two panels that resonate at the same frequency but just higher up in frequency.

Rog
 


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