Barry Dixon's Wood Veneered TL6s

Barry Dixon (Bazza) recently finished a pair of TL6 towers using a paper-backed wood veneer. He also wrote an extensive guide and kindly agreed to let us mirror it here.

For more information on other DIY audio projects, check out Barry's DIY Audio.

"I had been searching around for a nice pair of speakers for a fair price, and all of the in-store speakers that I'd listened to and read about, were all what I considered, overpriced. The only exceptions were the Wharfdale Diamond 9 floor-standers, which I thought were nice sounding for the price and a set of Dali floor-standers which I almost bought.

I was also looking at some of the DIY options and the VAF DCX kits, which from all the reviews I have read, are supposedly a fantastic sounding speaker, were being seriously considered along with putting together my own speakers from scratch using a pair of Fostex 206e drivers.

During all of my scratching around, I stumbled on the Loudspeaker Kit forums, and was quite intrigued by the products and the prices for the DIY kits, which were well within the range. Since I am based in Perth, and with the fortunate, for me anyway, location of the company in Perth, I was able to go down to the store in Leederville and talk to the guys and have a listen to the range.

I was able to take my own amp down to the store and plug it in so I could get a better feel for how the speakers would sound with my own equipment - I also bought my Azur 640C CD from the guys there as well, so it was a real chance to listen to the entire system. I was mainly interested in the F6 and TL6 speakers, and after listening to both, I found the TL6 to be more to my liking, and was soon walking out the door with a set!"

The Kit

"The TL6 is a transmission line design, which yields a deeper in room bass response than a vented alignment. The bass is less punchy than a vented alignment, but is more natural sounding and more satisfying with music where you want to hear subtlety and musicality in the bass. The result is particularly satisfying with acoustic bass.

The woofers are Vifa WJ17-00-08 Polycone drivers with fully cast magnesium supports.

The tweeter is the Vifa DG27TG-45-06, a fluid-filled silk dome tweeter which can be found doing duty in quite a few high-end manufacturers speaker systems. The technical details can be found on the Danish Sound Technologies website for those inclined to check out the specifics.

The crossover is a 4th order Linkwitz-Riley.

At some stage I will upgrade the inductors and the green caps.

The current inductors are 20AWG and I will probably replace them with 16AWG inductors. The caps I will upgrade to polyprops, probably Solens - I could go for AriCaps or something really pricey and exotic, but I don't think my ears are that golden that I would be able to tell the difference. :)

Construction

Construction of the speaker boxes was pretty straight forward and following the instructions as included with the speakers makes things quick and easy. The picture below shows all of the parts laid out as for a dry run and to ensure I have a good fix on how it all goes together before things get serious, and messy once the glue comes out.

All glued and ready for the top panel.

My trusty aide posing with the last panel ready to be dropped into place...

I might add that it's a good idea to have a friendly assistant to help out if you can find, or bribe, one to lend a hand.

My first attempt at a dry run was sans assistant (I was impatient and didn't wait for him to arrive) and lead to a mini-disaster. I had the box together dry and was foolishly trying to stand it up for some reason *shrug* and in the process one of the side panels popped out and bounced onto the floor... off course it landed on a point which made a nice little bulge and a ding in the corner of the panel.

I had to make up for my foolishness with some extra sanding before the veneer.

You may have noticed the crossover mounting - I have used the speaker protection plugs that came with the drivers for my M4's as mounting devices. I simply plugged them into the PCB holes on the xovers and then glued them in place with the wood glue.

Both speakers together and clamped while the glue dries. I've got the tops weighted down with my dive belt in an effort to make sure my dinged panel settles in as well as it can.

I left the clamps on for a good 24hrs.

The full set constructed and ready to go.

Sanding the speakers in prep for the veneer. I used a 160 grit on the orbital which gave me nice smooth joins and also added a bit of rough for "keying" the glue when applying the veneer.

Veneering

I decided to finish my speakers using a nice timber veneer and a good polyurethane finish. I had used a matt black paint as a finish on the M4s and while I was happy with it, I wanted the TL6s to have a different and luxurious look to them.

Of course, buying and constructing the TL6 kit means that the builder needs to make the decision about what sort of finish is required for the speakers. I found the painting to be quite a "fussy" process when I did the M4s and I wanted the TL6s to look as good as I could, so I decided to do a veneer finish.

The Veneer

After much searching, the veneer was found at a place called World Wide Timber Traders, down in Bibra Lake. If you go to the web site they have an area under products for "Natural Timber Veneers" which you can go into and call up photos of all of the timbers they have available. There is a quite fantastic range there and when I went down to the factory, they had shelves and shelves of stacked veneer panels. I had thought that the "Mappa Burl" would be a fantastic finish (and I still think it would be) but it was, as I had expected, one of the priciest in the range. It was just on $150 per square metre, which when you calculate that it takes just under 3m² to cover the TL6s, would have cost me around $400. As much as I would have liked it, I settled for my second option which was the American Cherry at $42m² for the paper-backed version of the veneer. You can also get a "raw" version of the veneer, which means it has no backing on it, which makes it a little tricker to apply. For a beginner, the guy at WWTT recommended the paper backed version, and I was happy to follow advice as a first-timer.

There are, I know, other options out there, specifically the "Iron-on" veneers that you can sometimes get at Bunnings and some timber and hobby shops. I found a supplier, carbatec, that had the pre-glued iron on sheets available in sizes 1200x300 for the sum of $33 per sheet. That calculates out to be around $96m2 and to get the 3m² required to cover the TL6's you would be looking at almost $300 and lots of fiddling and joins seeing as the side panels on a TL6 360mm!

One of the first things I wanted to be sure of before I started anything was that the glue I'd bought would be up to the task.

Would be nothing worse than having the speakers all finished to find the veneer peeling off due to dodgy glue!

Glues

Because I went for a veneer that was not an "iron-on" type, to source and apply the glue to stick the veneer to the speaker MDF. The guy at the timber place suggested a spray-on application for the glue, so knowing that aerosol cans of glue were available at Bunning's, I thought it would be pretty straight forward....

I ended up with this can of glue which according to the blurb on the back, would be up to the task.

Luckily, I don't normally take all blurb to be true...

For sale, one can glue, hardly used, ideal for sticking tissue paper together.

After my test patch had been left for a good 24hrs, I was still able to get a fingernail under it and with minimal effort, lift the veneer. Not good. Time to rethink the glues.

Talking to a friend that is in the house-building game, his suggestion was to ignore advice and use a brush and a good quality contact glue.

Who am I to argue...

Got these from my mates at Bunnings for just over $20 for 1.5 litres - more than enough according to the coverage rates on the back to do the 6m2 of the combined TL6 and veneer surfaces.

A test run of this yielded a piece of stuck on veneer that was only coming off in the event of a fire!

Measure Twice, Cut Once!

Measuring and cutting the paper-backed veneer was really quite easy and a decent pair of scissors and a builders ruler was all that was required. Of course, having an assistant to help out is always a good thing as well!

The size of the veneer panel was 1250x2450 so it was more than enough for both speakers, though proved to just be a little too small on one axis to allow all of the speaker panels to be one piece. I had to put one join on each of the speakers.

Veneering

The process of applying the veneer was pretty straight forward, and I got both TL6s covered in one, fairly long day. Took a good 10hrs, but quite a bit of that was the 40min cure time for the glue to reach a tack free point before I could bring the two pieces together.

The first panel to be tackled. The process is pretty straight forward - put a thin, even coat of contact glue on the surface of the speaker.

Wait around 40mins or until the glue is tack free.

The veneer side of the first panel. Again - put a thin, even coat of contact glue on the paper surface of the veneer.

Wait around 40mins or until the glue is tack free.

Bringing the two pieces together takes a bit of care. Being a contact glue, once the parts come together, it's pretty much impossible to separate them again. You had better make sure you have the veneer piece lined up bang on before any part of it touches the speaker surface!

The best way I found to do this was to cut some pieces of pine into dowels and use them as supports for the veneer above the speaker surface. While it was on the supports, I carefully lined the veneer up with the speaker panel.

Once the veneer was ready, the application method was simply making contact on the end, and using the heel of my hand, in a radiating pattern to make sure there were no bubbles.

It was simply then a matter of moving the dowels along the panel and using the heel of my hand to work my way to the end.

In the end, the whole process was quite easy and painless, and thankfully, bubble free!

A quick butchering of the veneer before using a little more finesse to trim around the rear port.

The best tool is the sharpest knife you have, ideally a stanley knife with a new blade, or a surgical craft style knife.

Running the stanley down the edge of the panel.

As long as the blade is sharp, and you take a bit of care, you can get a very good edge trim.

One word of warning - a sharp blade will quickly cut into the MDF and you may find yourself attacking the speaker panel if you go at it too hard! Leave some work for the sander, as it's safer.

Trimming down the long edge of the panel. One word of caution here as well. I had only allowed around 10mm of leeway on the edges, which was fine for the internal cuts of the veneer.

As this picture shows, I was cutting very close to the edge of the veneer on the paper backing as well. The problem with this I noticed a little late, was that the veneer at the edge of the paper backing was rippled and lifting from the paper backing.

So while I was gluing a bubble free finish with the paper, the veneer itself was lifted from the paper. The first coat of varnish penetrated and re-stuck the veneer to the paper, but it was a concern for a while.

Click for a close-up of the veneer lift.

Two panels of veneer coming together and with a quick hand sand, the join is damn near invisible with no evidence of the paper backing.

The trim around the driver cut-outs was a lot tricker to do than the straight edges, and it did take quite a bit of time an fiddling around to get right.

There's a join in this picture, the only one on the speaker and I tried to keep it in a spot that would be as unobtrusive as it could be.

Once I'd finished each speaker, I used a bit of cabots wood putty to patch up my nicks and cuts from the stanley and to make the join as seamless as possible.

Click for a close up of the join.

Putting the very last piece of veneer in place!

No more need for this dodgy old brush - in the bin you go!

Front of the veneered speaker.

Rear of the veneered speaker.

Both speakers veneered and have put the drivers into one as a quick preview of how it is all coming together and may look like as a finished product.

Thoughts & Tips

The Veneering process was not as onerous a process as I had been anticipating. Once the measuring and cutting was done, and all pieces laid out ready to go, it was simply apply glue, wait, place the dowels and line up the veneer, apply and move on to the next piece.

The contact glue was very easy to use and is probably a better option than using a spray glue as long as you take the time to apply it consistently and lump-free.
Use a sharp knife!
Don't try to do too much of the trimming with the knife, leave a bit for the sander!
Take your time with the driver cut-outs. It's easy for the stanley to start biting into the MDF if you go too hard.
If I was to do it again, I would change the order in with I applied the veneers:

Back Panel
Side Panels
Top Panel
Front Panel

This will ensure that the front panel is the panel without an edge facing outwards. This may be being a little pedantic, because I cannot pick out any edges on mine, but if you want to absolutely make sure of it, the order in which you apply the panels is just as easy to do it in the order described as any other order.

Finishing

The finish I used was Cabots "Cabothane" gloss polyurethane. I was after a very shiny, and deep look to the timber and the Cabots was recommended as a good priced option. My initial thought was to use a two part marine grade finish, but as soon as you mention "boat" the cost of any finish almost doubles!

One of the first tasks was a quick undercoat on the plinths, in preparation for a matt black spray finish.

I used a sample pot of undercoat for the job which cost me the grand sum of $3 from bunnings!

The first spray coat of matt black. There is a story behind the unpainted middle section...

I was initially going to mount the plinths as per the instructions, so direct to the base of the speaker, in which case, nothing but the edges of the plinth will ever be visible.

While I was dong the spray for the second coat, it was on my mind that I wouldn't mind using a set of spikes for isolation of the speaker... Hmmmm, how to use the plinth and still use spikes??

A flick through the Jaycar cat and a look at the spikes they had gave me an idea. I could rebate a few holes in the plinth and drop the spike bases down the holes, and if I did it properly, still use the pre-drilled holes in the speakers as markers for mounting the spikes on the boxes.

I think it worked well, but you can be the judge.

Here is my trusty aide doing the penultimate coat (number 4) of cabothane to the speakers.

After doing the previous three coats over the past three days I was getting a bit weary of the sand, varnish, sand, varnish, sand, varnish, sand, varnish process.

At this stage the speakers were really starting to look a million dollars, though the battle with runs and blemishes was never-ending. The gloss finish really looks superb, but it is very unforgiving of any errors or uneven application.

The pair drying after the 4th coat. At this stage they are a real "dust magnet" and I had them inside protected from what was a windy afternoon.

I had thought to put a black spray through the ports, but anyone that wants to come into the house and poke around the back of my speakers and comment about the colour inside the ports will get a black eye!!

I really liked the finish at this point and would have stopped at this except there were a few runs and blemishes that meant the sander still had a little work to do.

Running the orbital over the boxes for the last sand. I was using a 400 grit paper for all of the sanding and found it to work fairly well.

It gave a good sand that smoothed out any runs and bumps quite easily and was not that fine that the sanding process took forever.

There were no scratches or any roughing up of the finish that impacted or remained visible after the next coat

Just a close up of the sanded speaker showing that even after the sander had done it's work, the surface was still highly reflective.

You'll probably have noticed that I didn't bother to apply any blacking out paint around the rebates for the drivers. I had test fitted the drivers to the boxes before and after the veneer and the fit seemed to me that the fit was that tight and flush that the chance of MDF showing through was going to be very slim.

I guess in truth, I thought it was overkill and I just couldn't have been bothered. If it did become any issue on final fitment, I could always use a brush and carefully apply some black paint where needed. In the end, the fit was as good as expected and it was not an issue.

<<--- Click for bigger pic.

The 5th coat of gloss and drying in the lounge room.

At this stage I was well and truly over the whole process and was just eager to get them together so I could have a listen. I'd bought them to listen to after all!

I could hardly wait for them to dry... as a matter of fact I left my finger prints on the finish for both in my eagerness to test how quickly, or slowly, they were drying! :)

I'm quite pleased with the finish and the fact that it was all as a result of my own, and my trust aides, work, to which I'm thoroughly grateful.

The picture does not do full justice to the finish.

Finally starting the final step in the process and have stuffed the cabinet in preparation for mounting the drivers.

One area of confusion that I will note down for anyone else reading this is what appears to be a deliberate phase reversal on the tweeter.

I was paying particular attention to the instructions and lining up the lugs with the stripe to the positive when I happened to notice that the striped positive for the tweeter went to the negative pad on the crossover!

This was a bit of a concern seeing as it was not mentioned in the instructions that there was a phase reversal. I debated whether it was a production error on my crossover, and checking the crossover for the other speaker and finding the same situation, I decided it must be a deliberate reversal.

Anyway, the striped lead is going to the positive terminal on the tweeter, regardless that it goes back to the negative pad on the crossover, and the speaker sounds fine.

(LSK says: Barry's right, this is a deliberate phase reversal of the tweeter.)

A look at the rear of the speaker with the binding posts.

The finish on the backs of the speakers were really superb and it's a shame the back has to face the wall for most of it's life!

All drivers mounted and the speaker ready to be lifted into place on the plinths and finally be plugged in for the first listen. Yay! :)

I have linked a close-up of the front of the speaker so you can have a look at he finish and fit and that there is no MDF showing around the edges of the drivers.

Click for close-up.

Final Speakers

"After a few days I started to notice a few runs and blemishes on the speakers, that while I don't think many other people would have noticed, it was starting to bother me... A bit like a sore tooth that you can't help going back to and exploring, even though you know it's annoying.

I'd pretty much used up my full litre of gloss cabothane on the five coats to date, and knowing how fussy it was to get a coat I would be happy with, I decided to make it easy on myself and do a final "repair" coat in a satin finish. I know, a bit of a cop-out, and please don't let my experience deter you if you want the deep lustre of a gloss finish, but I was after a solution that would give me a final coat I could happily life with.

So, off to bunnings once again and much to my pleasure, I found the cabothane finish in pressure pack sprays which made things even easier. I pulled the drivers back out, blanked off the driver holes and pulled out the sander once again for a quick once over of the trouble spots. I then did the final coat with a satin finish cabothane pressure pack, re-assembled the speakers and am now more than happy with the end result.

The tops of the finished speakers.

The satin finish really took the harsh glare off the finish and still gives the full effect of the timber.

Where the gloss finish was a little too smooth and cold to the touch, the satin finish invites a touch of the speaker and it adds a little texture.

While the look is not quite as brilliant as the gloss, I definitely prefer the feel and the ease of care that the satin finish seems to have added.

Close-up of the driver mounting screws that came with the kit.

At a distance the screws were still visible and really stood out from the drivers, which was not something that I particularly liked.

I have a set of Dynamic Audio 3-Way speakers that do duty as party speakers from time to time, and I noticed that they had allen-keyed screws on them that looked like a better match for the TL6 drivers.

Out with the cordless and after about 30mins of buggerising around, I had all of the screws swapped over, including for the tweeters.

Looking at the picture, you make think that the original screws were a better colour match, but I can assure you, the allen-keyed screws look better from a distance and when up close to the speaker.

A view of a finished speaker in all of it's glory.

My innovative spiked plinth!!

The pair of finished speakers. They are almost like a new set of babies and I am sure I drove a lot of friends nuts sending this picture out and jabbering on about the whole thing!

Actually, as a result of this picture, a friend queried me about the speakers, where I got them from, what they cost and what was involved. I sent him through the specs and the link to the LSK website and he then decided to take the plunge and upgrade!

He sent through a progress picture on his speakers (He bought a surround system, F5s, C5 and D4s) and he is now debating on what type of finish to use on them.

Marcus - you owe me one beer!

Looking down the front at the drivers.

Both Speakers.

The detail on the spikes and plinth arrangement. It worked very well, and the spikes slotted home into the indent on the spike bases with no problems.

How much this adds to sound quality I'm not sure, but I reckon it looks bonza!

Just a detail shot of the spike base sitting inside the plinth. The rebate for the spike base goes a good two thirds of the way into the plinth.

Grilles

I was debating about making up some grilles for the speakers, and finally decided, that just for the sake of protecting the drivers I would add them.

I know the grilles will detract from sound quality if played with them on, so will make them as quick and easy to get on and off as I can.

The frame for the grill is made from a plank of 16mm MDF that cost me $7 from my good friends at Bunnings.

Here I've just marked out the frame ready for cutting. I'm making it easy on myself by using one of the pre-cut edges as an edge on the frame.

I only had a jigsaw available so it was a long slow process to cut out the frame and the internals. I have only finished one as a test to see what it would look like and I am still debating the final design.

For the moment I have gone with a full length grille. But I think that may change to a half length design so the front timber finish still gets a show with the grilles on.

The grille cloth is available from Jaycar as a pre-cut package or from Altronics by the metre. I got mine from Altronics for $17 a metre.

Here's the rough and ready first look at the full length grille.

It actually looked a lot better than I expected it to when it was on and you look at it from a few different angles.

Off course, in the final version I will spray the front of the MDF black so that it does not show through the material as distinctly as it does here.

I may "scallop" the grille and finish it at about this level so some of the timber finish on the front is still visible with the grille on.

I may also whack a badge on the bottom of the grille!

Another angle of the speaker with the grill in place.

Listening

"Well, okay you say, that the looks, just what the hell do they sound like?

To be blunt, I'm biased because I put them together and did the finish, but I reckon they sound damned fine! In all of the shopping around that I did, they comfortably match the sound from speakers from the "big' brands that were well into the thousands.

I have been running selected stacks of my favourite discs though them, and though I'm sure having the Azur and the DIY amp driving them assists with sound quality, I can quite easily say that I have never heard my CD collection sound as good as it does now.

Dire Straits leap out of the speakers, Pink Floyd has detail that I've never heard before and my jazz collection has come back to life! Diana Krall, Eva Cassidy, Cassandra Wilson, Norah Jones, and Tracey Chapman never sounded so good, and Miles Davis, John Coltrane, Johnny Hartman and Nat King Cole are in the room with you. I'm listening to Grace by Jeff Buckley as I type and it is just sublime.

I have a CD called Mule Variations by Tom Waits and the first track on that is a real test and the TL6s do it with ease, even with the volume at ludicrous levels... I've also played my Tool CDs at the ludicrous settings and believe me, my ears and nerve (I think the neighbours must wonder what the hell is going on with all the loud music I've been playing lately) gave out way before the system did!

In short - I'm very happy!"

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