3 Way Floorstander Build - Striving for high end...

And what have you seen Dave??!😉

You've let me secret out. 

Arke No, I just didn't want to look like some silly old bugger who'd forgotten to post a link.                        

THE BUILD: LET THE CUTTING COMMENCE

This was my first speaker build (the subwoofer came later), so I first needed some decent power tools!  I researched online and bought a new table saw and palm router.  I didn't fancy building a complex cabinet with a circular saw and hand tools!

The 3D design allowed me to produce accurate drawings of every part.  I began with the construction of the easier parts and progressed from there as I got more proficient with the new tools.  These are some internal braces - cut on the table saw and then routed with the circle jig and palm router:



The rear spine was constructed from three 40mm x 60mm bamboo ply 'posts' - these were trimmed (on the table saw) and bonded together to form the rear spines:




These spines have been cut slightly too long and will be trimmed exactly later.



Once the spines were bonded and cured the brace and top panel rebates were cut on the table saw - the blade depth was set to the required rebate depths:



I next began the front baffle and started with the rear panel - this was cut to shape and rebates were cut:



The top (wider section) of the rear baffle panel is where the tweeter would sit. The lower section has been reduced in width to provide a recess for the bamboo side panels. This image shows the rear baffle panel, braces and rear spine dry fitted together:



The lower part of the top panel (far end of the picture) is also dry fitted. The top panel has a rebate for mid/tweeter rear chamber panel.



This is the freestanding (dry assembled) cabinet skeleton with most parts in place. This image shows the slanting (25mm thick) MDF panel which separates the crossover chamber from the main speaker enclosure - cutting these angled rebates was a challenge, however, the table saw certainly helped! Note: the front baffle requires another (hidden) rebate, so the top panel does not locate correctly yet.




The top brace still requires a hole at the rear - this will open the bass enclosure behind the mid/tweeter chamber.

THE BUILD: FRONT BAFFLE AND BONDING OF CARCASS (excluding cheeks)

Work continued on the front baffle, which is a lamination of 18mm (rear) and 22mm (front) MDF panels.  I used a circle jig and palm router to rout all driver holes.  It is always wise to have the drivers to hand as they can vary in size a bit - a snug fit is required, but not too snug.  I left a little leeway (0.5-1mm) for the overspray during the painting process too.  This is the front baffle with mid and bass driver holes:




For time alignment purposes the tweeter had to be 18-20mm behind the mid driver.  The front panel (with mid/bass) of the front baffle was 22mm and therefore 22mm in front of the tweeter.  A 3mm MDF panel was bonded onto the tweeter (rear) panel to bring the distance to a 19mm offset.  This is the tweeter hole in (rear) front baffle with the 3mm MDF bonded in place:



All driver and port holes cut and the front and rear baffles are bonded into one stepped baffle:



The main skeleton of the speaker was complete, these were bonded together before work would start on main side cheeks (bamboo) and top (tweeter) cheeks:




This is the completed main carcass without side cheeks:



The next post will cover the challenging task of producing the sculpted side cheeks.  DUST, DUST and more DUST!

THE BUILD: LET'S GET CHEEKY...!

The construction has been reasonably straightforward until now...  Most parts have been relatively simple to make with a table saw and router.  The main (lower) bamboo side cheeks would certainly be a challenge.  The 40mm thick bamboo ply would be sculpted into a curve on the outside - this curve would be done mostly by hand (and a belt sander) and had to match perfectly.  The inside of the cheeks required many rebates to exactly marry up with the inner carcass and braces.  Here is a image of the inside of one cheek:



The rebates were cut first with a router, this took a long time and a lot of measuring and checking.  The next job was to sculpt the curves - I began with the table saw and removed some material on the front and rear of the curves.  Here are some images of the cheeks after a rough table saw cut:





It was pretty rough at this stage, but extremely exciting as it was the first glimpse of how the speakers would look!   The next task was to head into the garden and make ALOT of noise and dust...   Armed with a belt sander, ear defenders and a dust mask I began the epic sanding process:





LOADS OF DUST and many hours were spent in the garden...



Some of you may be wondering how I got the curves exactly the same on both sides of each speaker and on both speakers???!!!  This is perhaps a rather obvious flaw in my design... A CNC machine would certainly have helped here!    Without modern tech, I had to resort to the old school methods of using my eye and feel...  Fortunately, the bamboo helped massively too - the plies were extremely consistent and accurate, so I could judge the consistency of the curves (from panel to panel) by measuring the position of the ply change.  This ply change line had to be exactly straight and the same distance from the front (or rear) on each panel.  This sounds very painstaking, as it was!!  Sand a bit, check the lines are straight and consistent across all panels, sand a bit more, check the lines, sand a bit more, check the lines AND SO ON, AND SO ON, AND SO ON....  Many hours later my obsessive self was happy the curves were done:


{Part way through the process}

This shows the top cheeks rough cut too.


After a lot of work I was very happy with the cheeks - the bamboo plywood is stunning and I love the way the plies change through the curves.  The next job is the much easier top cheeks...

That's a very kind offer, perhaps on a future project (these were built a few years ago).

Roughly where is the pad sander based?

Magnificent!!

Indeed! The skills some folk have  ..........

Again great camera work, the speakers ain't half bad either 

THE BUILD: THE PAINT JOB - PART 2... MY PRECIOUS!!!

The speakers were soon to get the shiny. shiny treatment.  After 7 coats of primer and a lot of filling and flatting I now understand why piano black is an expensive speaker finish.  The speakers went back to the spray booth for 3 coats of 2-pack black car paint, followed by 2 coats of clear lacquer.  The professional spray booth is pretty important for achieving a top notch finish.  It is very warm (around 25-30C), which cures the paint more quickly and effectively.  The floor of the room is covered in metal grids and air is continuously drawn down to keep any stray dust from floating around.  The speakers were meticulously cleaned and compressed air was used to remove as much excess dust at possible.  Any specks of dust will cause an imperfection. 

On goes the black... 

 

I was thrilled with the finish after the black and lacquer coats - beautifully impressive - this is before the final flatting and polishing too!!







The keen eyed amongst you will note a very slight 'orange peel' effect.  This is normal and most cars (even expensive ones) have this.  The guy did a great job of getting the lacquer just right so it 'flows' (but doesn't overspray) and gives a very smooth finish - a very difficult skill and not to be underestimated!

The final flatting and polishing was done by pro too.  This is best done with a random orbit polisher and is apparently very challenging - one wrong move and you can easily polish through the lacquer.  This is not good, as it's a re prep and re spray of the final coats.



The final finish was well worth all the effort - over 24hrs of my time & elbow grease and the cost of the spray booth time (and paint).  Nearly there, mostly just final assembly to go... 

Outstanding

As well as the build I have to admire your patience! very nice