Building the MKII

StratManSi

Active Member
I built a 12” subwoofer for my lounge about a year ago and it was always just ok – I made the enclosure about 1cu ft and it could do with being bigger I recon.
I have very little info on the driver so it’s all guess work and experimentation.

So last weekend I decided to have a go at the MKII box – the plan being to make it about 50% bigger and see what happens.

Other design “improvements” will be:
Plate amp isolated from cabinet
Double thickness front and back
Grill – new baby forces speaker cover-up
Bracing

Decisions to make:
Ported/sealed – comments invited!
Covering?
 

StratManSi

Active Member
Here's the MKI:


 

StratManSi

Active Member
The MKII has a couple of set dimensions due to placement and also I plan in future to use it as a centre channel stand so I know how wide it will be and how tall (450x525)- the depth will have to be decided based on required volume.

So far I have cut the two pieces of 15mm MDF that will form the double back panel and built an internal enclosure to house and isolate the amp from the main cabinet.

Amp box:


Mounted to back panel:


Hole cut for amp:


vent holes drilled:


It fits!
 

StratManSi

Active Member
Second back panel routed:
 

StratManSi

Active Member
looking good :)
 

StratManSi

Active Member
I also found an Audio Drive AD12-300 used on eBay for a reasonable price so I bought it - nasty no brand car driver will not be making it into the MKII. This has solved my lack of data to decide the volume also as the new driver will work well in a 50l sealed enclosure :)
 

StratManSi

Active Member
Finished all my panel cuts last night and did a dry assembly - not too bad considering I did it with a circular saw - quite pleased with myself :)




It sure is getting heavy too.
 

StratManSi

Active Member
Marked up baffle for driver and grill frame.

 

StratManSi

Active Member
Grill frame cut:


Happy with that!
 

StratManSi

Active Member
Sides glued and screwed:


Double baffle glued up and setting:

 

StratManSi

Active Member
Top and bottom braces marked up:



Gas flowed :)



Fitted:


 

StratManSi

Active Member
The driver turned up today :)

 

StratManSi

Active Member
Time for a hole, I love this bit!


Now I can finish planning the centre brace:



Like a glove!

 

StratManSi

Active Member
Last nights progress:
Centre brace finished and test fitted:





Starting to look like a subwoofer now :)

 

StratManSi

Active Member
Got the fixings in the post today so test fitted the driver and glued up the centre brace - couldn't resist feeding it some watts as well - boom :)





 

StratManSi

Active Member
Hole drilled for the terminal plate:

 

StratManSi

Active Member
Thanks!
It's certainly evolved from what I started with, I'll be sealing it up tonight I hope. Then comes the difficult bit - giving it an outer skin of 16mm oak :)
 

mojogoes

Remembered (1961-2016)
Great build your skills look very competent and i'm sure the finish will look just as good as the rest of the build..................Good luck!!
 

StratManSi

Active Member
Thanks! I've been winging it and getting away with it so far!

Last night saw the last of the basic box construction - back panel in place and laminated. All the inside joints were sealed with silicone:



if the socket plate turns up today then there could be a test firing this weekend :)
 

StratManSi

Active Member
I decided it needed a testing so I mounted the amp :





.....and gave it a bash - wow! A huge improvement over the mk1! It sounds way more controlled and precise :)


I'll be giving it a proper spanking tomorrow for sure.
 

Phil1975

Distinguished Member
Great work...always good too see a new DIY build start to finish...!
Look forward to seeing it 100% complete..!
 
Last edited:

StratManSi

Active Member
Not much action this weekend due to visitors but did get round to trimming the front and back flush. Also had an opportunity to do some listening tests and the results were good :) I ran a sweep test and using my ears only it seems to have a very flat response and rolls off at about 23Hz - pleased with that. I also experimented with filling by stuffing a couple of cushions in it, I think it sounded better without if indeed there was any difference at all?

Pleased with that:

 

StratManSi

Active Member
The oak planks I intend to wrap the box in turned up today, got them marked up and rough cut to size :)






 
Last edited:

KelvinS1965

Distinguished Member
That's looking good Simon. I did something similar, but just recycled an old Oak AV unit I had but I think yours is going to look better in the end. :thumbsup: It does surprise people when they ask where the bass is coming from as they don't realise it's a sub:

.Completed rear from front.jpg
 

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