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New project - TG’s Faital 3 way classic 15”


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Howdy folks, ordered and paid yesterday for the tweeters, crossover components and various bits and pieces from Jantzen Audio, I went for the more basic kit with fabric tweeters and the lower (but still high) grade caps.  
 

I plan to put together the crossovers first, and am in the process of sourcing the 8” 18sound 8nmb420/8 and 15” drivers Faital 15PR400/8 delivered to Sydney. 
 

Will update as I go, looking forward to digging into the project.  I’ll construct the cabinets at a DIY workshop in Marrickville that offers a 5 week course with additional facility access outside of supervised class’.

 

 

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Howdy folks, ordered and paid yesterday for the tweeters, crossover components and various bits and pieces from Jantzen Audio, I went for the more basic kit with fabric tweeters and the lower (but sti

This build just got interesting.     

I actually got the Tweeter (Be version) and Woofer locally. I think the Mid I got from Germany Thomann as the UK was out of stock at the time. The link below is to the UK site.   I opted for

  • Janus77 changed the title to New project - TG’s Faital 3 way classic 15”

Booking into the Makerspace BYO project woodworking class in Marrickville Sydney from 19th November (3hrs per Thursday for 5 weeks).

The instructor suggested Trademaster at Granville for wood.  Trying to source the right thickness is proving difficult though, 18mm and 24mm seem to be the standards, Troels gives a tolerance of 19-22mm for his design.  I don't want to deviate from his plans.  Have emailed asking for advice on this.

 

Found this website to assist in cutting planning: https://www.cutlistoptimizer.com/ - i'll need 3 of the 250 x 125cm boards. Which leaves me a free 75cm x 250cm section to use to construct grills and some feet.  Looking like $160-180 per sheet.

 

Drivers.

Faital 15PR400/8 options:

Lean UK

DJ City australia

 

18sound 8nmb420/8 options:

Lean-business.co.uk

I'd tried contacting their Malaysian distributor, as there is no Australian distributor, but haven't been able to make any headway.

 

In the interest of avoiding import duty, it might work out best to order the 18sound from the UK and the Faitals from DJ city.  the 18sound are out of stock, more expected in the next few weeks.

 

Regarding finish on the speakers, my wife says we have enough wood, so i'm going to go with an ebony black wood vinyl on the top, sides and bottoms.  I thought it might be fun to do a maroon faux leather facia, or maybe vinyl on the front (with the leading edges of the sides, top and bottom in the black vinyl, so they look black with grills on and then have some colour when removed.  Any suggestions on the best place to source vinyl?

 

Hoping to have the crossover components by early next week, will get started on assembling immediately.

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Bit of progress:

 

1. Reply from Troels, 24mm birch is fine (even better than 20mm), just extend the depth of each cabinet by 2cm.

 

2. Found a wood supplier who can deliver to the workshop for a reasonable fee.  The sheets are 45kg each (24mm x 2500mm x 1250mm), the cut calculator has me using 75% of the sheets, which would have the wood alone for each speaker at 50kg.  Add drivers and crossovers and i guess they'll be around 65kg each.

 

3. Bit worried about moving them around.  Troels recommends 5cm feet, i found these low profile castors which can carry up to 130kg.  I think these might be a good idea: https://dandenongcastors.com.au/collections/range-low-height/products/lhnna40bh

 

4. Requested invoice for 2 x Faital 15pr400 and 2 x 18 sound 8nmb420 from Lean-business.uk.  Not critical that they arrive before the woodwork course starts on the 19th November, but i will need them by mid December to ensure i have time to cut holes.  Hopefully the 18 sound come back in stock as expected in the next few weeks.

 

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Glad you got it from the horse's mouth - 24mm is a very good thing. If you rout the woofer hole the full 13.1mm deep, it doesn't leave much for the screws to grip. I'd be putting a reinforcing ring around the inside, or at least little ply pads to give the fastenings more.

 

(I've been using 48mm for my 15" driver baffles, and either 30 or 43mm for sides and back, but more important is adequate bracing).

 

The Baltic Birch sheets that turn up down here (Tas) are  2440 x 1220mm, the same as 8' x 4'. Maybe there's less danger on the way to your neck of the woods, but you can expect some bruising of the edges, so I imagine you'd need to accommodate that in your CNC program.

 

I personally would avoid the decorative side-ways strips in the front and rear panels - this severely weakens the structure, negating the benefits of plywood. But you'll be covering them anyway, so I guess there's no issue there.

 

Reckon you'll need a few of practice runs (on scrap) to get the driver hole routing right, if you're going to be folding vinyl into them - sounds very difficult, and is it worth it, if making grills? I can't visualize how you'd join the side and front coverings. Are you sure she won't just tolerate "one little wafer" of wood on the sides?

 

Edited by BioBrian
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Hi Brian, 

 

Thanks for the advice on reinforcing for the woofer mounting.  Regarding the sheets, i've got room to play around, having not built cabinets before, my thinking is whenever i need matching pieces cut, i make sure i do them all on the same saw setting, so that i don't have to come back later and try to match cuts exactly.

The cutting sheets look like this, the program left gaps in between most of the panels, when i'm cutting the mirroring panels though i'll leave no gap so should have plenty of spare wood for bruising etc.

image.png.bbbc1849fc0be22f633ae78d7039126d.png

 

I'm not planning to use the decorative strips, so no worries there.

 

With the driver routing, good advice thanks i'll do some dry runs before drilling the panels proper. 

 

I've started thinking it might be easier to just leave the front panels as wood, and laquer them instead, maybe even use a stain to darken them a little.  I'll still do the grills (young kids with fingers that love a dust cap), am thinking i might cut the grills short at the bottom so they leave the ports visible, meaning there'd be a wood look at the bottom, might be a nice appearance.

 

Ps. Ordered and paid for the 18 Sound 8nmb420,'s, and the Faital 15PR400's from the UK.  Managed to get a small discount on the Faitals by taking a set they'd used to for photographs and measurements (10 minutes at 1 watt at 1 metre).  No blemishes, full warranty and otherwise unused - i figured i avoid the risk of a faulty product by taking these too as they've already been connected and tested by the retailer.

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Following on from Troels confirming 24mm birch was fine to use, i started calculating the cut sizes needed with the additional 20mm depth in the cabinets.  Sorry it's a bit long winded and i'm not sure if it matters, however i do want to stick to his plans;

In maintaining the front baffle face dimensions, while increasing the panel thickness by 4mm, the internal width is reduced by 8mm, and so is the height.  The internal bracing is also 8mm thicker further reducing the internal volume. 

 

We have 3 sections within the speaker:

1. Tweeter box - Troels advises size is not important, only that it is sealed and has space for the wires.

2. Mid box - 18.9 cubic litres.

3. Woofer box - 120.7 cubic litres.

 

Mid box: easy to calculate, if i maintain the centre position on the upper internal horizontal brace, i lose 2mm space at the bottom of the mid woofer box and 4mm at the top = 6mm lost.  The width of the box is reduced by 8mm.  therefore i need to move the front face of the large vertical brace back by 1cm to maintain the same volume as Troels plans:

 

Cubic measurement - mid box

 

depth

width

height

cubes

Original

21

41

22

18.94

New 

22.02

40.2

21.4

18.94

 

 

 

 

 

Any concerns with my calcs?

 

Woofer box: i need to do some work on this, i have the time.  The original plans internal space, less the volume taken up by the braces gives the volume.  The braces have cut out sections to be factored in.  I take the new internal volume with 24mm ply, deduct the new bracing volume, and then check that by extending the cabinets 20mm in depth i'm maintaining the same volume, or else adjust accordingly.

image.png.4e0ddcb75f1d8575b4e2d76dac2e2c10.png

 

From Troels overnight:

image.png.46a885bb80576904d2fd568ed085267d.png

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And the woodworking workshop confirmed i can leave my project on their site in between sessions (also have access on other days once inducted to use equipment). 

Have booked the woodworking class from 19th November for 5 weeks.

 

Last element is to order the wood to be delivered, to the workshop, will wait and have it delivered a week before the class starts.

 

Woohoo.

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Your excitement is infectious - nice change in the present environment.

 

The box size calcs look fine - fortuitous that you can move the coronal brace 1 cm back, and the rear panel 2 cm back, keeping the proportions. If I don't say it, somebody else might - the volumes are not highly critical. Half a litre more or less in the mid, and many litres in the bass would hardly make any difference. But I do admire and respect your wish to keep to the spec; it's good for Troels too, so any feedback is meaningful.

 

But, having said that, I would err on the larger side for the woofer, having built 240 and 320 litre boxes for my 15" SB Acoustics drivers. I'll try to do some modelling in WinISD (have you done that? Lots of fun and confusion to be had) for the Faital.

 

Question: are you getting the panels cut over-size, and you'll do all the fancy angles and rebates yourself?

 

Also, the bracing doesn't need to be the full 24 mm - 18 would be fine, I think, especially if you leave a little more meat on the braces, ie rout the 125 and 190 mm holes about 10 mm less in diameter, in case they vibrate. This could save you a bit of cost, if the cut plan isn't ruined.

 

 

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Yep, i'm very excited.  A guy in my apartment building runs a music studio, he has a set of Duntech Princess - i haven't listened to them yet, but i'm very keen to.  Be interesting to see how these compare.  I'm not in it for critical listening, just for the fun of it.  Hoping these are a clear step up from my Mk1 Paradigm 9se (which i reckon sound great).

 

I haven't done any modelling, figured i'd leave all that to Troels and just go with his design.  i think the cabs are about as large as i can handle at this point, any deeper and they wont fit in the living room ;)

 

I'm just buying the 2500 x 1250 boards, and then at the woodworking course i will cut them using a rolling bed table saw.  They can angle the blade up to 45 degrees so i can cut the panels, and cut the corner angles, and the blade can be raised or lowered to allow me to cut the recess.. that or i use a router, they have hand routers and a table router.  I'll have all the dimensions planned out for the cuts, i'll wait to go to the class to get advice from the instructor on how to do the recess cuts for the front baffle to sit in etc.

 

Your idea on reducing the thickness for the bracing is a good one, it would save me some weight and cost.  Will muck around with the cut planning software and see if i can get all bracing pieces on the 1 board.  The main point is that the external parts of the box are stiff, so the baffles being 6mm thinner, so long as they're glued in well, should have zero impact on the rigidity of the cabinets.  Is this a fair assumption?  18mm is still pretty thick!

 

thanks :)

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A look at the driver in 120.7 litres, 1 W signal, 2 x 102 mm vents cut at 200 mm length. The tuning appears to be 38.4 Hz.

 

More knowledgeable people might have something to say, but this is what I came up with:

 

1523340517_Faital15PR400ventedsnip.JPG.ecc481d527461d43828cd023713ce5ae.JPG

 

It might be interesting for you, in anticipation, to look further into understanding Troels' choices by this method. He did say it's lighter, not a subwoofer driver. Of course room gain changes all the above.

 

Don't be shy about telling us more about yourself and your setup.

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Thanks for that Brian, so tuned to 38.4hz, does that mean the woofer will play down to that level?


Yes i did quite a bit of reading on Troel's website, i've been watching his builds for several years.  Previously i'd hoped to build the SBA 941 stand mounts, having the larger woofer.  However my Paradigm 9se have 2 x 8" woofers, so i decided i'd like more woofer surface area than i currently have, there's something addictive about melodious bass.  The Faital 3wc popped up which looked really interesting with it's high efficiency meaning i would not have to upgrade amplification.  Then the Faital 3wc 15", and having read up on his TL and TL2 and comments on what larger diaphragms can do, that was me sold.. :)

Something about there being no replacement for displacement.

I'd have loved to build the TL2, however cost and size they're prohibitive for me, his use of PA speakers rather than traditional hifi speakers is interesting and he's been happy with the results with these, so the speaker i've chosen seemed like a good compromise in building something of the same vein as his TL's (although i don't think these have high efficiency PA style wooders as he has them semi active) The first 12" faital's 3wc sold well and everyone who's bought it said they are great.  I feel like i'm going an oversized bass driver, however because it's a lighter driver, it should be fast, and the potential reduced bass from this vs if i'd gone with a traditional hifi woofer  is offset.  I think these woofers also go a bit higher in frequency than hifi style sub woofers which probably helps with crossovers and overall frequency response? (bit over my head that stuff though.. i saw the Faital goes to 4,000hz, whereas some of the alternative hifi woofers of the same size only go to 2,000)

Hoping for engaging sound that's dynamic and easily fills the room without needing to be turned up too loud (most of the time).

Really hoping they're the kind of speakers you can listen to at high volumes without fatigue, that seems to be the mark of a great speaker.

 

I have 2 amps:

Yamaha AX-570 100wpc

Rotel RA 970BX 40wpc (which i use primarily as i prefer the sound)

Odac

music from my PC, predominantly from Tidal.

Our living room is a bit of a funny shape, probably 5m from the wall behind the speakers to the wall behind the listener, then it's 12m wide or so and extends into a dining area behind.  There are plenty of bass traps (large sofa and foot stool)

 

I guess the plan in the future might be to go to a tube amp, or even try and get a class A, i saw a Chinese 100w class A on the classifieds last week with a switch for A or AB.  Something like that would be fantastic.

 

Our listening is pretty varied: Tool, Michel Goddard, Queen, Beatles. Daft Punk, Stevie Ray Vaughan, some classical.

 

My only concern is off axis listening, i'll have the speakers set up in front of the couch, we're often off in the kitchen to the side, the Paradigms are great front and centre but you lose a lot when you move away from them.  It's not a deal breaker for me though, if i put them on wheels i can just turn one to the kitchen when cooking.  it would be good if they have a bit wider dispersion than my Paradigms.

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Troels posted up a review on his website from the bloke who purchased the 3wc 15's that he built:

http://www.troelsgravesen.dk/Faital-3WC-15_Gavin.htm

 

Ironically the guy put them up for sale immediately after buying them.

https://theartofsound.net/forum/showthread.php?71062-FS-Troels-Gravesen-Faital-3WC-15-high-sensitivity-floor-standers

 

Hope the European lockdowns don't effect delivery of the parts too much.  Not a huge issue hopefully, i can get the cabinets finished and just go back for a few hours sometime to cut the front panels for the speakers if it gets to that.  Maybe keep the rear panels off too so i can attach crossovers after building.

 

Be interesting to see which of my amplifiers sounds best with these speakers.

 

I updated my cut calculations based on 2 sheets of 24mm ply for the exterior panels and 1 sheet of 18mm ply for the internal bracing, all good they fit.  the thinner 18mm ply will have room for me to cut lengths for the speaker grills too which is good as i'd prefer to use lighter wood for these:

image.png.03512e895111f775ac3fc9d0c038192e.png

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19 hours ago, Janus77 said:

Brian, ps. i see your profile pic looks like one of TG's design, are they?  How do you like them?

 

They are Troels' DTQWT-12s, built to spec, back in 2012. I like them a lot, and use them every day for domestic duties (TV, odd movie, YouTube samples, sometimes music).

 

They have a magic about them, in that they really fill the room nicely and sound good from any direction (bass comes out the back and underneath, as well as out front). They also measure well, and have that certain uniqueness of high-efficiency speakers. The beauty of grain in the Baltic Birch, Celery-top pine and Myrtle are very pleasing on a daily basis.

 

But I got a bit obsessed with getting lower bass extension, and began a long and at times painful journey to get that bottom octave: 20-40 Hz. This resulted in building giant 4-ways of my own design (with considerable inspiration from Troels and his website, and feedback from this forum). They're not pretty (except sometimes to their proud dad), they weigh 140 kgs each, they cost heaps, but they sound much more like the real thing than anything else I've heard.

 

Since then, I have filled in the "room holes", and got further bass extension (now flat down to 12.5 Hz) by building a pair of 320+ litre stereo passive subs.

 

This might explain some of my interest in your present build, and use of the Faital 15PR400. I've been busy battling with WinISD, with only partial satisfaction. The graph I posted above shows that your driver has very high sensitivity, but rolls off quite quickly down low. It's already down 4 dB by 42 Hz, the bottom note of a normal double bass. The lowest note on a piano (27.5 Hz) is down 14 dB. As I mentioned, room gain will make up for some of this, depending on speaker placement.

 

When I enter my other known 15" drivers, they show less bass loss around 20-30 Hz, but are all woefully below yours in output. This is the trade-off. Frustratingly I can't get any of the 18Sound drivers to work in WinISD (some TS Parameters missing in the datasheets), but it's obvious that you need this high woofer sensitivity to match your apparently amazing 8NMB420.

 

The guy who bought and flipped Troels' speakers mentioned the vertical dispersion - my experience is that speakers with the tweeter in the middle ("MTW") can suffer from lobing - you need to have your ears in a reduced band vertically, or they will do "comb filtering" (sound weird). This won't affect you while chopping your veges!

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Thanks Brian, interesting.  wow 12.5hz is LOW!  Crikey that must sound amazing.

So i guess i may need to angle the speakers slightly if the tweeter isn't at ear height for listening, i think our couch is a little low, i may put some wedges under the rear wheels - no doubt opening up a whole new can of worms with that comment ;)

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2 minutes ago, Janus77 said:

wow 12.5hz is LOW!

 

Sadly, mostly wasted, as I can't hear below 20 Hz... It's only occasionally that all that work and expense can be heard at all! Not much music has it, but it's truly awesome when it does, that's for sure.

 

You could set new trend, using audiophile cans of worms to tilt your speakers. Could become a hot seller for somebody. But it's unlikely to be a problem, if you're sitting at a reasonable distance.

 

BTW, I only had to wait a week for an item to arrive from Poland recently.

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The cheap shipping options are currently unavailable, so it's DHL Express only.  Should arrive fairly quickly when sent.

 

Grills: I had an idea to have these cut off short at the bottom to leave the ports visible, and some of the stained wood finish, however looking at the plans there isn't much room between the bottom of the woofer and the ports.  I'm guessing that I need the ports to stay exactly where they are in the baffle, or could i move them down a couple of cm to make room without impacting performance?  I'm being mindful of Troels advice that you can muck around with the internals a bit, but driver placement and the baffle size are critical for the crossover tuning to work.

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Ow, I'd cover the vents. Here we have mud-wasps, which can do terrible things to drivers, and you never get to find out until too late. In your civilized world rodents may not be a problem, but just the thought of possible nesting disgusts me! 102 mm is quite a big hole. You could lose a cat in there.

 

And you mentioned young people? Watch out the vents don't get used by creative souls (of any age) using them in a version of beer pong, or worse.

 

I agree, it's best to leave breathing room around the inside of the vents - worth it, not to move them.

Edited by BioBrian
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Good point, they're likely to have half of K-mart's plastic dinosaur collection in the bottom of the cabinets if i'm not careful.

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Just a little tip, when doing the mitre cuts for the top, bottom and sides of the cabinet, do the cuts at 46 degrees instead of 45 degrees - it helps to get a tighter and better finish on the exposed corners.

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Completed the internal volume calculation to check that the extra 20mm depth will result in the same woofer volume.  Not quite, it has only a very small variance of just of 1% in volume.  Again, I only want to stick exactly to his design - adjusted for the variance in plywood thickness.  I haven't worried about including any of the constant parameters like port tube, drivers or tweeter box as these will remain the same.  My main concern is Troels had the 15" enclosure volume at 120.7L, which my numbers don't reconcile with.

 

I may be getting too tied up with volume measurements, not having built speakers before I'm unsure how exact a science this part of the design is?  I understand the front baffle needs to remain the exact dimensions.

 

Below calcs based on using 24mm ply for the entire build, if anyone has time to check my workings i'd appreciate the assistance:

** note i've adjusted the depth of the 8" driver sealed box to ensure no loss of volume, which is why the depth of bracings A and C have changed slightly.

image.thumb.png.940880a27613ebad29f65df99fc10a1b.png

 

And if i reduce the internal braces to 18mm the volume increases by 1.1% (vs my calcs of Troel's original design):

 

image.thumb.png.972d30c724ae2761d4c874b725ee5052.png

 

When cutting brace pieces, i'll add 2mm front and back to allow me to cut teeth to slot them into grooves cut into the front and rear panels, same on the top and bottom of the large vertical brace.

 

I'm inclined to email Troels and query his volume measurements and ask if i need to increase the cabs to 120.7cbl as he advised earleir .  I'll wait to hear back from folks here first though, thanks all!!

 

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I don’t think anyone would be able to pick a <1% difference in enclosure volume. If the question is going to nag you however, redo the calculations until it’s spot on, then you’ll never have to wonder about it 🙂

 

SS

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Good advice, i imagine once completed, if i have any reservations on their performance i would be quickly convinced the 1% had me undone.. best off sticking to the specs exactly for my own peace of mind.

 

I think i need to go back to Troels and ask for his comments on how I've calculated the enclosure volumes, with regards to the 120.7L area he mentioned when we discussed using the 24mm ply.

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Using 18mm ply for the bracings, i've arrived at the following calculation on dimensions:

image.png.f4e2ca07d5e1eb0745a68194e8f38122.png

 

 

43.7mm deep instead of the 44mm Troels advised if using 24mm braces.  It's only 0.19cbl difference, being slightly larger volume than the OG design.

 

I don't think i need to check this with Troels, have looked at the numbers for long enough to be confident i'm maintaining internal dimensions. (famous last words)

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To do list:

 

1. source black wood vinyl - have found a few supply options which look good.  

This looks forgiving: https://www.amazon.com.au/VViViD-Black-Textured-Air-release-Adhesive/dp/B01BNT5DBW/ref=pd_sbs_201_1/355-1826262-5218520?_encoding=UTF8&pd_rd_i=B01BNT5DBW&pd_rd_r=4f3af288-d867-475f-9fa9-df708a08fbc9&pd_rd_w=aW5GV&pd_rd_wg=tdl5n&pf_rd_p=50c53f88-de65-41cf-869b-e0a249ae05bb&pf_rd_r=ZSHH3Q8JBXPZSMX1Y3G8&psc=1&refRID=ZSHH3Q8JBXPZSMX1Y3G8

 

2. buy castor wheels

 

3. Probably overkill, but seeing as i'm 190cbml over Troels design, thinking about gluing a sheet of this into each cabinet to further reduce vibration:

https://www.ebay.com.au/itm/223549385116

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Our couch sits quite low, these castors are as low loading height as i've found at 38mm.  Troels had 49mm feet on his speakers. 

25mm wheels might make them stick a bit on our carpet, but the height is excellent and i reckon i can muscle them around ok:

 

https://www.australianwheelandcastors.com.au/products/Ø25mm-1-Nylon-Polyamide-p157719527

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21 minutes ago, Janus77 said:

bottom looks like

 

Life expectancy of 5-7 years? That's a worry, even in these days of built-in obsolescence. DIY is (should be) a cut above all that. I had a terrible time replacing some stick-on stuff once, and swore against it. You can sand paint off later, (or paint over varnish), and do whatever suits at the time.

 

With your feet, I'd suggest you get an accurate-ish measurement of your collective ear heights when seated, and work from there. Tilting (forward, anyway) is much better than fussing with stands. Bass response will benefit from the bottom of the baffle joining the floor - no "baffle step loss".

 

I think castors would be a nuisance, especially on carpet - they are really cantankerous to move in fine increments, which you will need. 25 mm diameter wheels will be "up to the axles" in carpet!

 

Sliders (large - at least 50 mm square or round) would be much easier, and kinder to carpet.

 

Just throwing in some thoughts here. Don't let me dampen your enthusiasm; you are obviously giving this a lot of thinking time, and might be asking for some external influence.

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Thanks Brian, any input is appreciated.

 

I figured 5-7 years was the life expectancy on a car - hoped the wrap would last much longer on speakers inside.  Worth checking further with the supplier though.

 

I'll look into the sliders, have done some rough calculations on height and our ears are generally going to be slightly below where the tweeter will be.  Might be time for a new couch.

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I'm guessing the ear height thing will be fine. If you look at people's sketches of lobing, at a 3 m listening distance, it won't matter if you're within 6" or so. Same with a measuring mike. But of course we want to know the ideal, so we can be comfortable in knowing the reality of the situation.

 

Priority is really important. I'd be weighing up the difference between a level of crossover cost, and the cost of a new couch. More important might be avoiding leather as a couch material, as the reflections forwards to your ears can badly damage the sound. And that depends on the height of the couch back, etc.

 

Also appropriate springs to mind. You were writing about Sorbothane sheets as lining yesterday, at $1750 per square metre. This is not what you need for speaker lining - it's designed to go between 2 surfaces as part of CLD. You need mass and good adhesion. I haven't come across the bitumen pads that Troels uses in this country, but Dynamat Extreme has some similarity - needs a shiny surface to stick well to, ideally, so a coat of varnish internally would do. It certainly deadens boxes, according to the venerated knuckle test.

 

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Our current couch is a big bass trap, fabric. 

I wouldn't buy a leather couch, nothing worse than sitting on a leather couch on a hot summer day with shorts on.

To be honest, part of the agreement with my wife to build speakers was that she gets a new couch for the living room, so i'll keep in mind ear height when shopping and will stick away from leather at all cost.

 

I know what you mean about the small castors being difficult to move, however i think they'll be easier to move than sliders.  Will give it some more thought - i had it in my head that i'm better off with a lower profile castor even if more difficult to roll as it'll bring the tweeter closer to ear level.  Angling the speakers as you mentioned might be a better solution, i can just put some plastic floor savers under the rear castors.

 

Will take a look at the Dynamat Extreme material, thank you.  Would this material be best applied to the internal face of the front baffle (around the drivers)?

 

Crossover components scheduled to arrive tomorrow, will get started over the weekend if i can find some board to mount them on - it's happening!! :D

Edited by Janus77
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Don't worry about not having the exact enclosure volume that Troels has, it's the relationship between port length and volume that is key to meet a specified tuning frequency, so if you end up with 110 L you will need to change the port length to meet desired 38.5hz, use winsd to model different volumes and then see how the port length and graph changes. (the difference of 10L will not change the graph much)

Small volume changes will not make much difference to frequency graph curve - this also you can test using the Faital driver parameters.

 

And, if later on you go active DSP, you can force the driver to go lower and extend the range, given you are using this in a domestic environment you can trade maximum output for extension. 

 

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Tweeters and crossover kit from Jantzen is with the Fedex driver for delivery today, exciting!

 

Wondering if i try to get a coat of varnish onto the ply a few days before the first class, so i'm ready to cut during the first class?  Troels recommends a layer to reduce tearing when cutting the panels.  Added benefit is the vinyl will stick to a varnished surface better than an unfinished porous wood surface i believe.

 

Regarding the additional damping material, i think i'm getting ahead of myself with this idea.  I wanted to stay true to Troels design, he doesn't use any dynamat or asphalt matting in this design, so i think i'll forget the idea.  I can always go back and do it later too which is the great thing about DIY :) i'll be able to move up to the Be dome tweeter if i want in a few years, and can upgrade crossovers easily too if/when i want..

 

Castors, rather than trying to keep the height down, i'll go something slightly higher (60-70mm) which has a larger wheel diameter with proper bearings to make moving them around easier.  I can put some plastic caps under the rear castors to angle the speaker down slightly if needed.  Sliders are a good idea too, however i might want to move them in and out of rooms occasionally, I think wheels give more flexibility.

 

 

 

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Wife just signed for the FedEx delivery. 

 

Thinking through the clearcoat idea, might have to plan it a little as i don't want any clearcoat on the front baffles as i plan to stain these before doing a varnish or polyurethane finish, guess i just mark out the cuts and leave a little extra room for the 2 front baffles so i can leave them unfinished.

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Having just completed a build of these speakers, a few comments that may help you avoid my pitfalls!

 

- Plywood is quite brittle so varnish coating is recommended or just be very careful (but expect some damage in handling).

- Drill holes for speaker wire into speaker cavities before you add the felt. Otherwise the drill will destroy the felt. 
- Similarly for holes for castors.

- Add the castors before you close the speaker up. 
- If using feet, use Super Strength Araldite as it has a working time of 1h. The other versions cure too quickly for applying with an injection.

- Add 1mm to the diameter of drivers when you rebate the baffle. Measure drivers with a caliper!

- Same for BR tubes and sand down from the front baffle for a smooth finish. 
- Careful where placing the BR tubes as bolts for castors may impact. 30mm bolts should be ok to leave headroom between bolts and BR tubes. 
- Using 24mm BP means that each speaker is very heavy and hence difficult to manoeuvre. Make sure you have a buddy to help move. 
- Cut the felt with a Stanley Knife whilst positioned on the internal speaker panels. Then glue. Make sure you leave room so that felt doesn’t impede clamping the front and back. 
- Order more of the glue for crossover fixing than you think you need. The stuff that TG uses is wonderful. 
- Titebond 3 is really nice. You need about 1litre.

- Same for the tile glue - 1litre is about right. Definitely use gloves and a stiff brush. 

I’ll publish a complete build story on 3 Sad Bastards and it’s a topic on an upcoming podcast :)

 

Have fun - they are a cracking speaker!!!

 

Aris

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Thanks Aris, i'll look forward to your build story on the podcast. 

Which of the kit options did you purchase, and did you use 24mm birch, 18mm birch, or MDF in the construction?

I'd considered having the panels cut to spec, however i've always wanted to learn some woodworking skills, so construction in the Makerspace course is a nice way to kill 2 birds with 1 stone.

For the tile glue, did you use any particular brand for a reason, or any generic Bunnings product will do?

I'll order the Titebond 3 for the cabinet construction.

I have many questions, however i'll wait until having listened to the upcoming podcast! :)

Your comments having built these are invaluable, thanks for posting.

 

I'm a little concerned that my low end DAC and amp will become weak links even though i think they sound excellent with my Paradigm 9se, i imagine the 3wc will be more revealing.  Wait and see..

The kit has arrived today, so no opportunity to source more of the crossover glue.

Mid and Bass drivers have not shipped from lean Uk yet, the 18 sound were out of stock, should be back in stock next week.

 

Listening to your podcast right now, good fun.

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I actually got the Tweeter (Be version) and Woofer locally. I think the Mid I got from Germany Thomann as the UK was out of stock at the time. The link below is to the UK site.

 

I opted for the upscale x-over, who knows if it's that much better than the standard.

 

Satori TW29BN-B-8

$499 [ $1,007.91 ]

https://www.wagneronline.com.au/satori-1-dome-tweeter-beryllium-neo/speaker-drivers/audio-speakers-pa/tw29bn-b-8-81676/999531/pd/

 

18 SOUND 8NMB420/8

£126 ($230) [ $595.69 ]

https://www.thomann.de/gb/eighteensound_8nmb420_8_ohm.htm

 

Faital 15PR400

$369 [ $738.00 ]

https://djcity.com.au/product/faital-pro-fa-15pr400-15-inch-lf-driver/


 

For tile glue I used Dunlop Vinyl Adhesive from Bunnings. Works really well.

 

Dunlop 1L Vinyl Adhesive

https://www.bunnings.com.au/dunlop-1l-vinyl-adhesive_p6820002

 

Finally, in terms of cutting etc, I opted to design and get the whole lot done via CNC at Plyco (Melbourne). They were awesome to deal with. If you go that route I can share my designs.

 

I opted for 24mm Premium Birch Plywood.

 

Aris

 

 

Edited by aris
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