# My speaker build...about time I showed you



## terry j

Hi guys, been a while since I posted, and I keep getting a friendly reminder to get in and post! So I am! So there!

And also, I must acknowledge Sonnies enthusiasm and 'welcome back' the last time I posted, so this is a special one just for Sonnie. Don't we just love him??:bigsmile:

I am 95-98% finished, so as good a time as any to show you all. I hope that there are a few ideas here that might help/inspire others with their builds. Including one or two that, although I ended up not using, could be valuable to others.

Have had this basic layout for years, in what was basically a 'test box' that, to put it mildly, does not look too flash hot.

So much so, that one wit christened them the 'frankenspeakers', and the name has stuck in a rather affectionate way. May as well introduce the franks now so we can see what we started with.

Ta da!!










Ok, when this pic was taken the driver complement was an 18 inch PHL (7030), 6.5 inch PHL (1660) and a cabbasse tweeter, DOM 40. Ha!! As the build basically started a year ago (yes, serious!) a few driver changes have been made.

I now run a morel tweeter...unsure what model it is, it has been laying around for years and there are no markings on it whatsover, and memory...well it has faded shall we say? I have also changed the mid to a PHL 1360. It too has been laying around for yonks. For a long time I did not bother trying it, as I figured 'one PHL for another PHL, can't be too different' yeah?

Boy, was I wrong! I decided to give it a try as a direct result of the build, ie 'I should finalise all the driver choices before I go too far' type of thing.

glad I did.

So to the build, first off my biggest problem went something like, 'just HOW do I get a hulkin 18 inch driver into a design that looks halfway decent??'

After a lot of doodling on bits of paper, I came up with an idea that looked pretty good, and one that I doubted could be bettered. To get a bit of a feel in the real world, I made a little model of it. That will help give you an idea of what it is starting to look like, but I also feel a bit of a 'story' could be fun. Ie, will take you through the whole process.

The model










and the front view (needed to understand the 'concept' behind it all)










So, from the front view we can see that there are basically three sections, the base, middle and top, with an increasingly steep angle on each. So far so good.

I then had to work out how to build it, and work out the plan view. The how to build was easy, three sections stacked upon each other. A bit of fiddling with a compass produced the following formula

Hope you can see that OK...on the right is the elevation, on the left the plan. What is important with the plan is that it is all based on compass swings, to a set ratio of the dimension (taken from the elevation) of the relevant part of the baffle. The pic might not be very clear, but as you can see from the front view the dimension changes as we rise up the baffle, and at each succeeding slice (tho the formula remains the same) the radius swings change in step.

Clear as mud right? (EDIT, can see the pic is clear enough, so everything hinges on the 'x' dimension (from the front view), and the radii at each slice has the formula '1.2x' or whatever etc etc)

So I rigged up a router on a swing arm, where I could vary both the swing radius, and the pivot point that it rotated about










There is a cut piece of MDF in that pic.

I won't go into too much detail of the intervening stages, but will show a pic of the early days construction, as it will explain the 'brainwave' I had that sped things up.










That was mucking about with the top section (turned out fine BTW), every third or so slice had it's own skeleton rib (progressively changing per the swing formula), which was then bogged to form the surface.

Lot of work ha!

Brainwave!! Forget how it came up, but concrete was mentioned, and I realised that if I made it out of concrete (yes it is!) then all I needed was the top and bottom of each section, and could form the concrete with a straight edge, using the mdf formers as a guide.










You can see in the background a finished box, and in front of it the seperate sections of the one still to be done. The number of skeleton ribs required is vastly less than the earlier method, and hopefully you can visualise using a straight edge against the top and bottom of those sections to form the concrete...?? (of course I had to nail a few backing pieces in to pack the concrete against)

Here is a middle section concreted










All I had to do was to make the slices at each change in profile of the front elevation, so with a few dowels they could stack on each other, yet track the changing front profile (boy, I hope I'm not confusing youse all!!)

A shot from the back of a finished box. well not glued together but the three sections stacked on each other










I need to backtrack a little now, to give something that others might find useful in any curved builds they do. And it might be a bit more digestable if I start a new post.

PS, sorry about the slight miscalculations with the image sizes, means you have to scroll slightly to get it all.


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## terry j

Ok, when I first started I was doing 'every third layer' by cutting the relevant skeleton rib with the router. I then glued 'tons' of little blocks in between each layer to gradually fill in the body of the section.

may as well show you all for a bit of a giggle










As I say, since those early days I went to concrete, but back then I was stuck with trying to get a good finish. I needed that because at that stage I intended to veneer it all, so a good surface was required.

Bog got me a lot of the way there, but not good enough to veneer on. I then found a neat trick, and this is what may be of use to others here (even tho in the end I didn't use it as I went to concrete)

I basically skinned the the section with curved mdf, and it is the curving technique I want to outline.










It is all in this pic. I used cloudy ammonia, just painted it on the mdf (it goes kinda green) and then the mdf goes pretty flexible. Simply affix it to the former you want the mdf to bend to, and wait for the ammonia to evaporate. The mdf is then formed to shape.

You can see in the pic a piece of formed mdf, and the little gas bottle I used to demonstrate the trick with. The broken piece of mdf next to it shows what happens when you bend a non treated piece around the same gas bottle, in short you can't.

Not limited to three mm mdf either, here is a 16mm piece of mdf that I treated with ammonia and bent around (a larger of course) former










So, curved speaker builders, off you go!!

Hmm, maybe I didn't need to outline it in a seperate post after all!!

Anyway, here is a top that was skinned by curved mdf










that went into the bin heh heh, as I started after that on the concrete model.

Hope that ammonia trick can be of use to some others.


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## Sonnie

:unbelievable:

Terry... what in the world are you doing man... that is wildly cool!

You gonna have to quit waiting so long in between posting. :whistling:


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## terry j

Ok then, all the planning, calculating and building the router jig etc took a while. As did the first way of building with blocks then onto the concrete method.

Funny how once you get an idea in your head that it can tend to block new ideas from coming.

As I said, I always had the idea of vennering the back, and tossed around heaps of ideas about what to do with the baffle, special paint effects, whatever. I leaned towards using vinyl on the front baffle, but wondered whether or not I could get it to stretch over it.

BUT, how to veneer the box?? I mean not a lot of leeway for mistakes right?? I seemed to have a pretty good match between each section, but even little things like getting a perfect veneer joint at each interface...so the project basically sat at two concreted boxes for a few months as I pondered how to do the veneering.

Then....the inspiration.

http://www.diyaudio.com/forums/showthread.php?s=&threadid=140086

(please have a look at it, to me at least they are stunning)

See what I mean about the first idea stopping new ones?? All that time I pondered how to veneer the box and put vinyl on the front, NOW all I had to do was swap them around! duhh. Simple, vinyl on the box and veneer on the front!!!

Next day went out and bought some vinyl to try, success!! (tho to be honest, for a while there I didn't think I'd manage to get all the wrinkles out)

Raw box, not even glued together yet (can just make out the tape holding the sections together under the vinyl for the trial)










Excellent, and even if I say so myself it looks pretty promising.

So for the finished version, the only change (apart from actually gluing the sections together that is ha ha) was that I put firm foam under the vinyl. Gives a real nice feel to it.

[









(ok, that pic is a bit out of order, as it has come after working out the baffle and top, but still a shot of the vinyl and maybe an indication of the foam underneath? ie it has a 'spongy' quality to it)

So the boxes were sorted, now had to work out the baffle. (note the fully planned procedure in play here!)

Won't go into ecrutiatingly boring detail, but in the end decided on a roundover, with gently sloping sides










I also stained the veneer quite dark, and you can see that as well as the roundover.

Here is a veneered baffle, not yet stained, on the box










Have to take a few more shots, but they have been stained and almost done.

A hiccup was found tonight, basically the baffle (made up of mdf glued together) is warped!!! How did that happen? I mean, if it was solid wood that had a face removed I could maybe understand how it could warp or cup, but mdf????

Anyway, think I have found a solution, and should know for sure tomorrow. NO WAY am I building the baffles again! Still, I have not got recent pics but soon will.

Pretty sure I can work around the problem, and if so then within a week I will have the drivers in the box and start measuring and calibrating. Oh, forgot to mention before now that it is a fully active tri amped system, run by a deqx unit.

So even tho the basic system has been running for years, new boxes etc means I redo all the measurements and calibrations again.

So soon more up to date (and hopefully completed) pics, and _measurements_..we all love measurements yeah??:bigsmile:

I may start a new thread on one aspect of those measurements, think I have found something useful that may help others.

And would be my little contribution to HTS in (part) exchange for the wonderful gift of REW given freely and without conditions by the wonderful people here. (I take a liberty here) by thanking John and Sonnie and Bruce and Wayne et al on behalf of all HTS members. (arrogant are'nt I for assuming that role??)

Anyway, more on that use of REW when I start the new thread.

For my system, what comes next (with a vengeance) is room treatment, which will be another huge saga, mainly due to the aesthetic considerations imposed by my room and historic house we live in. So that too will be chronicled.

But hey, maybe I should just finish these first??


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## terry j

Sonnie said:


> :unbelievable:
> 
> Terry... what in the world are you doing man... that is wildly cool!
> 
> You gonna have to quit waiting so long in between posting. :whistling:


hey sonnie, thanks man. been busy kapiche?:innocent: besides, you can see how slow I am in posting yeah? fixing all those hamfisted spelling mistakes (a few beers don't help either)

was gonna ask whatcha doing up so late...then realised it was _me_ that was up late ha ha

anyway, more in a few days I'd say. thanks for your interest


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## ktaillon

It's good to see something different... Nice Job.

I really like the vinyl covering. I almost tried this on a baffle once.


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## keelay

Bril-liant.

I have got to try the MDF Ammonia Trick THAT could come in handy making some pretty sweet custom speaker cabinets. I'm happy to hear that it works on 16mm (1/2") as well. I'm planning some computer speakers and will likely use this method in the box design.

Thanks for the awesome ideas. Keep the posts coming!

thanks,

Kyle


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## ironglen

That curving trick is way cool. If I ever build curved mains, I'll have to consider that. Thanks for sharing!:T


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## terry j

keelay said:


> Bril-liant.
> 
> I have got to try the MDF Ammonia Trick THAT could come in handy making some pretty sweet custom speaker cabinets. I'm happy to hear that it works on 16mm (1/2") as well. I'm planning some computer speakers and will likely use this method in the box design.
> 
> Thanks for the awesome ideas. Keep the posts coming!
> 
> thanks,
> 
> Kyle





ironglen said:


> That curving trick is way cool. If I ever build curved mains, I'll have to consider that. Thanks for sharing!:T


cheers guys, hope it gives you enough to experiment with for your own builds.

A few quick notes, 16mm is more like 5/8, 12.5 mm is half inch.

You must bear in mind that the thicker the mdf is, and the smaller the radius the more force required to bend it and hold it. 3mm (1/8) is very easy indeed, as would 6mm (1/4) be. If you wanted quite thick walls, then I'd suggest laminations of some sort.

In any case, experiment and good luck!!

A cut and paste from the original build thread on diy (so if some things don't quite make sense, it's prob because this thread was a synopsis)

******************************************************************************

Did I ever tell anyone I hate hi fi? that I hate speakers? that most of all I hate building them??!!

You saw earlier that the stain was too dark so I stripped it back and started again.

Still could not quite get the colour of my sample, but kept going. Dunno why, but the finish with the tung oil just would not come no matter how many coats!

Got sick of it, and rang a mate and asked him if he could spray them for me, sure no probs. Set up a time with him, and-yep-stripped it all back yet again to bare wood.

Drove two hours to him on a late sunday, and when I get there he has no stain after all!! I HAD asked him if he wanted me to stain it before I arrived....5.30 or so on a sunday afternoon, nearest bunnings is thirty km away, give me a break!

There was an 'old timer' there doing some stuff, had a lot more experience than my mate with spraying etc, assures us that with not the slightest shadow of a doubt, not matter how well I had stripped them, there would still be oil on the pores and that the lacquer simply would not take.

load them back into the car, and drove home again.

Geez I hate building speakers!!

BUT, re-stain them for the third time..hey!! getting the colour I wanted, apply the oil again and blow me down if the shine etc is now appearing!!

go figure. Guess they needed that round trip?

Sooo, did I ever show you my base plate and spikes??










Ha ha, the spikes are made from 16mm threaded rod! Be strong enough ya reckon??

It was just the nature of the beast, mainly due to the vinyl, but as the baffles could not be glued (due to the vinyl, and how do you ensure an airtight seal, a bit hard to apply weights on the baffle with this shape), the entire thing is bolted together.

I am such a sloppy worker, that turned out to be a good thing. I had to re-vinyl the two boxes...I managed to gouge a hole in one tripping over stuff laying around, and the other got bog on it that I could not get off.

Having all the pieces bolt together means I can always pull it apart in the future and do things like that.

Hmm, what if I decided on _pink_ vinyl for example? easy peasy! 

So that was the base plate on one, with the other sitting nest to it with a spike in place and a spike sitting loose. Just turned up the holders on the lathe.

So screw the bottom on, bolt the baffle on then the top plate, then bolt the midrange chamber in. Bit of a pain, but watcha gonna do?

Hmm, all these potential leaks, the next step is to put it together, cross my fingers and hope like crazy that the thing is airtight.

A quick shot on the way inside, basically wasting time and putting off the big test.










and another










A shot of the old (RH) one from the LP










and a shot of the new (LH) from the LP










They are pretty dark (as can be seen from the outdoor shots) and my room is dark, so I had to slightly lighten that shot of the speaker.

Well, good news, no leaks! phew. Tonight the second was hauled in a fitted up, again no leaks and I am now listening to them as I type.

I can tell you, a bit of a relief!



















If I had thought about it, I probably would have put a hard piece of wood to mount the speakons on (still under the vinyl tho), rather than on the foam under the vinyl. It compresses slightly, not too big a deal and nothing important enough to feel I have to fix.

I will probably put another couple of coats of oil on the top plates later, but I'll just let it all harden up for a couple of weeks. then a good wax, and it is finally finished.

It is very close to, if not actually, a year since I decided on the design and built the little model to see if it had legs.

And it feels it!


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## JCD

Those look awesome. 

That's all I can say.

Just awesome.


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## Jason Schultz

yep! one of the most stylish and good looking speakers i've seen to date here.:clap:


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## terry j

hey thanks guys!

am getting used to the new look. will be sad (with a ritual bonfire no doubt) to sat goodbye to the old workhorses.

But of course the most important thing is how they sound. there was always that little fear in the back of the mind you know?

It may be obvious, but whatever the reason (more stable..the old used to rock 1/2 an inch ha ha, or thick 1 1/2 inch concrete walls or anything else) the most immediate observation of the improvements are 'solidity'..either in the bass or the rest of the spectrum.

So even tho it makes sense that it should be better than the old, still a relief.

No point really in any of us critiquing or raving about the sound we have-leaving aside that we could very well be biased or simply have no other external reference-but even to me the improvement in the bass performance was unexpected.

My bass (those phl 18's are pretty special, simply based on exposure to alternative bass that I've heard) was always very good indeed. They do not go lower now or anything like that, but the increase in 'solidity' was startling, and downright scary.

BTW, as these things seem to be of vicarious interest. even tho they are 18's they (perhaps counter intuitively?) do not go that low at all. I only really get extension to about 35 hz, after which it drops off fast. Maybe I should say that I'm strictly two channel? Not that I know much about it, but 35 hz for HT would be, like, phht! so what!! ha ha

Some may even say that for two channel 20 hz is important, not my finding at all. I know I have heard many 2ch systems that DO go to 20 hz, but dunno what it is, the sheer effortlessness of these drivers??, I have yet to hear bass that even comes close.

Ooops, that was veering towards me describing my own system, so enough of that. I'll leave it simply with the observation that, however good it was, or however you would describe it, the entire presentation has improved, as well as looking better

Could I expect or hope for anything more than that??

In a few days I will recalibrate the whole system, so updates will be with measurements, then off to the acoustic section to work out proper room treatment.

catch you then, and stay well!!


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## peterselby7

Very nice speaker system Terry. I like the vinyl wrap!


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## mdrake

That is one of the nicest DIY speakers I have ever seen!!!!!!!!!!!!!!!!!!!!!!!!!! :T 

Matt


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## Lucky7!

mdrake said:


> That is one of the nicest DIY speakers I have ever seen!!!!!!!!!!!!!!!!!!!!!!!!!! :T
> 
> Matt


You should _hear_ it too: one of the very best systems I've ever heard.
Looking forward to October, TJ.


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## bambino

:TWOW! Those look somthing youd see in a highend audio shop. Nice work!


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## terry j

holy moly, this is a blast from the past! Hah, just looked at my last post, almost exactly a year ago! Sniff, makes me all emotional it does haha.

Peter, the vinyl wrap was a solution to the big problem I had, but thankfully it actually looks (and feels) fantastic. Feels?? Sometimes I can't help myself, I still fondle them:rofl:

And thanks very much to mdrake and bambino for your kind words. I do think they look great, esp given the big aesthetic problem, how to make an 18 inch woofer look good.

Brett, as always, thanks. October is rolling on inexorably, and I too am looking forward to it.

May as well give a little update now this thread, like frankenstein haha, has risen from the dead. Hang on, it was dracula not frankenstein no? Anyway, had to get the franken gag into it somehow.

Due to Bretts (oops, A9X) kindness I have been playing around with extras since this was built. I have added a second deqx to the system, which allows me to make it a four way and have subs.

The addition of the ten inch (to make it a four way) has been a big improvement, Brett lent me some acoustic elegance tens for the trial. I will replace them with ten inch PHLs after experimenting.

The subs have added just that bit of bottom end fatness. The 18's are certainly no slouches in the bass department, often switching the subs out make no real difference, but when needed they are there.

Luckily for me (can't remember how much detail I went into in this thread) the baffle bolts on and off. I could lie and say I anticipated changes haha, but anyway that means I can take the baffle off and build a new one to replace, one that now incorporates the ten inch.

I _think_ I have just enough room to make it happen. Am waiting on dimensions to check...if it doesn't fit then waaahh, not sure what I'll do.

The box to house the ten will take up yet more internal volume, taking it away from the 18. I may have to make the baffle itself quite a bit deeper to compensate.

Still, we'll get there eh? Somehow.

Anyway, thanks guys, will be a few months I'd say before I really get into the surgery, till then the ten inch can just sit in it's own little box on top.

I can't tell as I type this response, but if the link to peters website is in his sig I recommend people to take a look. Very comprehensive, and boy he must have put some work into it! 

(If the link is not in his sig, maybe peter can pop back in and give it?? Is that allowed??)


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## peterselby7

terry j said:


> I can't tell as I type this response, but if the link to peters website is in his sig I recommend people to take a look. Very comprehensive, and boy he must have put some work into it!
> 
> (If the link is not in his sig, maybe peter can pop back in and give it?? Is that allowed??)



LOL... yes the link is in my sig. 

Thanks for the plug Terry... Your speaker plans are definitely worth duplicating. Maybe we should get some CAD drawings together on your behalf. Others may like to duplicate your efforts. 

Again, very nice execution and design!

Peter


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## spasticteapot

Does anyone here have any pictures of the ammonia procedure?


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## tcarcio

How in the world did I miss this when it happened? Was I in a coma? My friend you have some sick talent and you should be very proud.:T I know I would be. Great job.:clap:


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## ironglen

Those DO look fantastic and unique. 

I'm curious if building a cabinet with concrete skin results in a nice finish (concrete) and if it could look good stained (not painted but stained as a nice floor looks). By the way Terry, what type of concrete did you use, how was it 'applied', and how much does one of yours weigh?


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## Dodger66

Very Nice workmanship!


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## iskandam

very unique look, impressive indeed!


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## terry j

ironglen said:


> Those DO look fantastic and unique.
> 
> I'm curious if building a cabinet with concrete skin results in a nice finish (concrete) and if it could look good stained (not painted but stained as a nice floor looks). By the way Terry, what type of concrete did you use, how was it 'applied', and how much does one of yours weigh?


\Can I apologise firstly for appearing rude?? I did not mean to, have been 'off' forums for a while. Sorry for the late reply (I must subscribe to the thread I guess)

I did feel whilst doing it that a 'raw' concrete finish would look kinda neat. Maybe experiment with oxide in the mix, see what it looks like when dry. I even did an experiment (as the raw finish was looking OK) with adding bits of broken chalk, see what it would look like with colours poking thru.

Can't remember what the conclusions were tho! 

You can get a good smooth finish, but concrete as such takes so long to go off it slumps etc. Maybe I did not explain in this thread (?), in the end I went away from concrete because of how long it took to go off. (and the constant slumping)

In the end, I got small gravel (5mm, 1/5 inch) and used base coat (used on gyprock, think the yanks call it drywall) rather than concrete. I measured enough base coat to take up the air space between the gravel, if that makes sense. The base coat goes off quickly, max half an hour or so.

in effect the base coat is just sufficient binder to hold the gravel together.

So rather than concrete, call it 'solid rock'??

So that answers what type of 'concrete' I used. In the end I did not worry too much about the finish, as long as it was good enough for the foam and vinyl to go on top.

How was it applied/? Again, can't recall what I said in this thread, so a brief explanation. I used the 'top and bottom' profiles as an guide I could run a straight edge across, that meant I could scrape the mix to shape. A little mental picture should explain that. Of course I had to put a barrier internally to pack against, so I just nailed scrap MDF on the inside, the top and bottom patterns were 50 mm wide, so that means a layer of 'real stone' bigsmile two inches thick.

Anyway, an update whilst I am here. I have now made it a four way..added a ten inch...as well as run two mael 18 subs.

I run the lot now with two deqx units.

As I had to shoehorn the ten into the baffle (I had to measure twice before cutting to make sure they would fit!!) it meant I needed to build anew baffle.

funny how years later it turns out lucky the baffle just bolts on and off eh?

A quick pic to show how it looks. I ended up real lazy, and for now just used black vinyl on the baffles as well. The veneer DOES look better I reckon, but as they just bolt off it is easy to take off the vinyl and veneer them when I get the enthusiasm.


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## tesseract

Looks like you are having a lot of fun with that, Terry. Wish I could give a listen. 

Your build gets a five star vote and a dancing banana! :dancebanana:


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## elbzb

I'm not surehow mind works either.


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## Owen Bartley

Wow, I guess I missed these the first time around, but I'm glad this thread came back to the top because those are some truly inspiring speakers you've built. I also like that they're still evolving (although I must say that the veneered baffle with vinyl back was gorgeous).

And to think I was just wondering where all the "big" speaker projects had gone. Not that there's anything wrong with the little guys, but sometimes it's nice to see an undertaking such as yours and just read on in awe.


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## pato

AMAZING!!!
this is one of the best I ever seen
I am sure it was fun to build


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## robbo266317

A great job! I bet you are proud of them.


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## terry j

thanks guys.

fun to build?? Hmm (hahaha)

I guess it was in a lot of respects, I really enjoyed the problem solving aspect. That it ended up quite unique both in looks and how it was done is/was satisfying.

In many ways i am proud yes. It was a relief to finish them tho TBH.

Does not mean much on the net I know, but they sound damned fine, certainly not looking for anything better.

I MAY some day go and redo the finish on the front baffle. Doubt I'd go back to wood veneer tho. I will show you what (if I do it) I'd be considering. (click to enlarge)

http://www.veneersupplies.com/products/Enchantment-Copper-Veneer-36-x-96.html

or maybe

http://www.veneersupplies.com/products/Zebra-Copper-Veneer-36-x-96.html

Did I say I enjoy 'problem solving'!! It would be a cakewalk with square boxes, but with roundovers etc the problems magnify. I do tend to overthink things before i get into it, so it may be easier than I fear.

That will be a way off tho, so if and when I'll show pics.


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## paulspencer

It's bizarre to find randomly on a forum speakers you have first heard in the flesh. I heard these last year and they were the speaker that inspired me to ditch open baffle and go back to box speakers. The thing that I liked about open baffle speakers (size of the sound stage) was shown up by these. Easily one of the best systems I've heard.


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## Projectorlover

Old thread, but thanks anyway for sharing. Exactly what I was needing for my project.


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