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


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Wow, that's very fine work there, @aris. Wish we'd seen more of that as it emerged.

 

Hope you don't mind me using your pic as an illustration - in an early post here, I said I'd prefer more meat on (eg) the lower vertical struts of Brace B. Making the 4 lower holes 5 mm less in radius would give those struts another 10 mm width and attendant mass increase. With rounding of all hole edges I reckon it'd be just right. Wonder if I'm alone here?

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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.     

As is the norm, i was unable to complete my optimistic jobs list.  However this time i accepted and refused to be rushed.  I did however make quite a bit of progress. 1. support rings for woofers

7 minutes ago, Janus77 said:

time to cut

 

You're a lucky man! Awesome machines.

 

Wanted to say - don't cut your front and back panels until you've dry-clamped up the sides and ends. The furry edges on 45 degree cuts are not easy to measure for length, and the rebate depths are not perfectly predictable either.

 

And the 45 or 46 degree thing - even with these amazing tools, I wouldn't trust that they cut the exact angle it 'says on the tin'. They need test cuts and fit-ups.

 

This is hotting up!

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Only 3 of us in the class, so plenty of time with the instructor when needed.  Might only be 2 in the class, seemed like 1 person was slightly unsure if they were going ahead with it.  After the course, I can use the facilities for a fee going forward.  
Looking forward to getting stuck in properly next week!

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13 hours ago, BioBrian said:

Wow, that's very fine work there, @aris. Wish we'd seen more of that as it emerged.

 

Hope you don't mind me using your pic as an illustration - in an early post here, I said I'd prefer more meat on (eg) the lower vertical struts of Brace B. Making the 4 lower holes 5 mm less in radius would give those struts another 10 mm width and attendant mass increase. With rounding of all hole edges I reckon it'd be just right. Wonder if I'm alone here?


Don’t mind at all. I should have chamfered the brace holes just forgot!

 

Also I did adjust the diameter and placing as I was using 24mm (and had created grooves/slots).

 

It’s my first build so there are some things I would do differently next time :)

 

I am of half mind to do them again at some point as the plywood cost is minimal cf. the overall. 

 

Part of the fun is learning!

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Might bunk off early today and log a couple more hours in the workshop.

Realized i need to physically mark each piece and facing, so i know what is what.  Same number of pieces of wood as there are numbers in the alphabet!

Had a couple of moments thinking about cutting fingers off, probably a good thing, all the machinery i'm using is dangerous if you don't take care.

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External panels first cut, going to tidy up depth of each to exact measurement and leave height over so I can cut to correct length when cutting 45 degree ends.  

getting more confident using the table saw, just make sure those fingers are well clear!

 

That’ll probably be it for me for today.  

9A5AFDB0-0E99-486A-B62A-30AF92249F9D.jpeg

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Love the bench! And I thought mine was heavy. Having a flat bench is such a blessing for a job like this.

 

It seems to have an inbuilt clamping system, so routing holes should be relatively easy (you'll obviously need a sheet of scrap under your work when routing).

 

But consider, if you know the exact width of your saw blade, routing as many brace holes as possible before cutting the sheets up - they're a pain to clamp and rout when small. (Could cut each slightly oversize, and trim with a buzzer when doing final fit-up). I know that won't appeal to your sense of accuracy 😄.

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1 hour ago, BioBrian said:

Love the bench! And I thought mine was heavy. Having a flat bench is such a blessing for a job like this.

 

It seems to have an inbuilt clamping system, so routing holes should be relatively easy (you'll obviously need a sheet of scrap under your work when routing).

 

But consider, if you know the exact width of your saw blade, routing as many brace holes as possible before cutting the sheets up - they're a pain to clamp and rout when small. (Could cut each slightly oversize, and trim with a buzzer when doing final fit-up). I know that won't appeal to your sense of accuracy 😄.

 

It's a great workshop, i can see myself paying to use the facilities again after this course.  I've already amassed a decent little cache of offcuts which would be more than useful for chopping boards or other small objects.  Pricing is pretty reasonable, $250 for 5 full days you can use over 3 months, or $280 a month for 6 day a week full access.  The table saw is a really nice unit, it  has a scriver blade for getting a very clean cut, and the rolling bed is huge, clamps too which were very helpful today.

 

The metal bench is just beside the workshop, it's actually for the metal workshop i was just using it as no one was doing metalwork.  Upstairs they have a big woodworking room for gluing and finishing, i'll be up there once i've finished all my cuts.

 

The saw blade's 3mm, there's a routing table where you can set a guide at a desired distance from the edge.  I might go with your suggestion and just route the a 24mm wide channel instead of trying to cut a tooth to fit a smaller section.  I don't see any downside to this approach, does anyone?  As I progress, i get a clearer picture of what i need to do.  Thoroughly enjoying it!  

 

ps. my sense of accuracy has a large margin for error, your suggestion is perfectly appealing :) i've already cut the sheets up though, no going back now..

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Oh and taking the time to look at the panels and figure out what grain i want on the front baffles was fun.  Taking into account the driver placement i think they should look pretty good.  Now where do i source some red dye..

 

On my cut list diagrams i've labelled the panels A through to Z, and then i'm marking the facing material with that letter, and also marking depth and width edges so i keep the grains consistent (even though i plan to vinyl).  The physical markings are helpful, would get very confusing very quickly.

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4 hours ago, Janus77 said:

Oh and taking the time to look at the panels and figure out what grain i want on the front baffles was fun.  Taking into account the driver placement i think they should look pretty good.  Now

 

:wub:

 

Biting tongue firmly here...

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Hard to find extra time for the project - young kids..

 

I'll have to wait until the Thursday class to get back into it, and I have Friday off so should be able to log 3 hours then. 

Hopefully 6hrs of workshop time this week has all panels cut to size including internal bracings, and the rebate/step down in the sides, top and bottom panels for the front and rear baffles to sit in.

It would be great to get the circles cut out of the bracings too this week, might be a stretch though.  I'll cut bracings slightly oversized first cut, then trim them to exact measurements 2nd round.

 

Plan this week is:

1. Cut sides, top and bottom panels to exact width and lenth, and cut 45 degree ends (Will do this on thursday as i'll want the instructors guidance before i cut).  Thinking it through: i'll get an offcut length of wood from one of the throw away bins, set the blade at 45 degrees (it doesn't go past 45 otherwise i'd take advice and cut 46), cut 45 degrees on 1 end, then set the stop to cut the length i want the side panels to be, and then cut the other end at 45 degrees, then measure to check that i've got it bang on the length.  Adjust if necessary until i have the exact measurement, then i'm good to go on the side panels.  I'll do the same for the top panels.  Luckily there are bins full of wood offcuts i can use.

2. Cut 18mm board up into first cut of bracings

3. Rebate the step down in side, top and bottom panels for front and rear, need instructor advice on best way to achieve this (router?)

4. mock up/clamp the sides and top of the box, measure this prior to final cut on internal bracings.

5. Cut out circles on bracings.

 

Looking at what i need to do, it's probably a stretch to get all of this done in 2 sessions.

 

As impatient as i am to work on the project, it's probably better that i have time in between sessions, it allows me to think through what i need to do next.  I've caught a few issues with my planned approach already in this way.  I'm feeling a bit short on time though.

 

Fun fun.

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Just a little (preemptive) finding for this speaker. Tonight I tried amping the woofer separately. Like Troels, I'm running valves on MT and find that a powerful AB or D class amplifier on the woofer really improves SQ. I've also tried a AB amp across all drivers (bridging the MT and B taps) but find that valves work really well on the top end, whilst the woofer needs a grippy amplifier to shine!

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Thanks Aris, glad you've taken some time and tried a few setups before making any reviews/comments. 

As keen as i am to hear your in depth review, I appreciate that waiting until you've had time to properly gauge the performance and decided what the best setup is for you is important in allowing you to make a proper assessment.  Much appreciated.

 

My wife has already prompted that "we'll probably be looking at amplifiers next, won't we..", so this info is very helpful.  I have no experience with tubes/valves, am hopeful at some stage another Sydney person looks at building these who potentially has a valve amp can come and have a listen using their own amp before committing to the build, 2 birds with 1 stone.

 

How many watts are you feeding the MT and B separately?

 

Have you painted them yet?  I'm really keen to see how they look finished.

 

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1 hour ago, Janus77 said:

How many watts are you feeding the MT and B separately?

 

Have you painted them yet?  I'm really keen to see how they look finished


Im using an Octave RE 320 which is 130w into 4 Ohm for the MT.

 

Whilst I still have the Michi M8’, they provide 1800w into 4 Ohm. I think the woofer is rated at 400w and 800w peak, so the Michi are clearly overkill. I reckon bass amp at around 500w into 4 Ohm would be about right given the amp I use for MT. 

 

The challenge is gain matching when running two amps like this. 
 

You’ll need a decent Digital Voltage Meter to measure input and output voltage, and an ability to adjust gain quote granularly (eg via an attenuator or such capability in the bass amp).

 

My challenge now is to find a bass amp - probably Class D, eg Hypex or maybe Purifi based, that has a gain of over 28db or 34db depending on whether I use RCA or XLR from my pre amp (Octave HP 700).l to the bass amp. 

 

The pro amps such as QSC, Yamaha etc would meet this requirement and also have plenty of grunt for bass but they have fans so not so keen. 
 

I’ll probably ask March Audio to increase gain on his stereo Purifi amp in the end. 
 

Aris

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1 hour ago, PKay said:

@arisSome photos would be greatly appreciated. 


I have yet to decide on finish! My wife through a wide ball when she said that the natural birch look was growing on her so not am vexed!

 

Aris

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Aris, does the Octave run as a preamp for the bass amplifier?  so you need the gain on the bass amp matched so that it increases in line with volume on the Octave running integrated on the M/T? 

 

Just trying to get my head around it..

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2 hours ago, Janus77 said:

Aris, does the Octave run as a preamp for the bass amplifier?  so you need the gain on the bass amp matched so that it increases in line with volume on the Octave running integrated on the M/T? 

 

Just trying to get my head around it..


My setup is separates for pre and power. The Octave pre has simultaneous out on 2 x RCA and 1 x XLR.

 

The idea is to attenuate (reduce gain) on the bass amp to match the gain of the (valve) power amp for the mid and tweeter. 
 

I guess I could always attenuate the valve amp but I feel that wouldn’t be as nice sounding cf. to reducing gain on the bass amp. 
 

What’s really surprised me is the range of gain across various amps and across RCA and XLR. There doesn’t seem to be a uniform approach or standard which I guess now that I think about it should not be a surprise as amp architectures and implementations will differ across brands and models. 
 

But it would be nice to have a database of gain, impedance etc to help find the “right amp”. I’m resorting to blind sampling of amplifier spec sheets to find a powerful, high gain, no fan, and reasonably priced amp for the bass. 
 

Hope that clarifies, let me know if not and I’ll draw up a diagram maybe?

 

Aris

 

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Hehe, sorry Aris my knowledge of amplification is fairly limitied.

 

Does the  Octave pre have speaker outputs which connect directly to the M/T binding posts, or you have a valve pre into both a valve power amp for the M/T, and a class D for the bass?  I guess my question is in amplification do you have 2 pieces of equipment or 3?

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Just now, Janus77 said:

Does the  Octave pre have speaker outputs which connect directly to the M/T binding posts, or you're looking at a valve pre into both a valve power amp for the M/T, and a class D for the bass?  I guess my question is in amplification do you have 2 pieces of equipment or 3?


I have 1 pre connected to 2 power amps which each connects to the speaker terminals (one to M/T and the other to the B).

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On 24/11/2020 at 1:49 AM, aris said:

Just a little (preemptive) finding for this speaker. Tonight I tried amping the woofer separately. Like Troels, I'm running valves on MT and find that a powerful AB or D class amplifier on the woofer really improves SQ. I've also tried a AB amp across all drivers (bridging the MT and B taps) but find that valves work really well on the top end, whilst the woofer needs a grippy amplifier to shine!

 

I tried the same with the DTQWT but with with 4 SS mono blocks. They were all the same so didn't have the same volume difference issues. I actually got a decrease in SQ which I put down to lower quality interconnects and speaker cable. I was expecting the bass section to improve with the extra power.

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On 19/11/2020 at 11:57 AM, BioBrian said:

Hi Hugh,

I'm presuming these are for the inside of the boxes?

My Jantzen binding-posts (which I don't use) have 6 mm threaded shafts on the inside, but would need a 10 mm eye on the outside.

Or a fork with at least 8.5 mm inner width.

Maybe yours are different?

 

I put these aside and gave it some though.  I'm going to cut the eyelet (opposite side to the wire), and spread it to fit.  should work ok hopefully.

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Looking forward to getting to the workshop this evening.

 

Plan is:

1. Cut exact depth (depth as in speaker cabinet depth) of sides, top and bottom panels.

2. Cut 45 degree corners on sides, top and bottom panels.

3. Cut rebate for front and rear baffles to sit in.

4. Mock up box, measure rebated width to confirm baffle width and height needed. (measure internal width, depth and height too for internal bracing)

5. Cut front and rear baffles to size.

 

Back to the workshop tomorrow for 4-5hrs too.  Will aim to:

1. Cut internal braces

2. Cut rebates for braces to sit in on side and top/bottom panels 

3. Cut holes in braces

 

Will see how much i get done tonight, the plan for tomorrow may change.

 

Fun fun!

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When cutting the rebates (don't know if you'll use router like I do, or table saw as Troels does), err on the side of a little deeper, as you can trim the sides later, but can't trim the baffle (outer lamination only about 1 mm thick).

 

I'd suggest not too deep on the rebate - the finished product will give a visual impression of the panel thickness, whether you know better or not. Better for it to look thicker. Also less waste of material and energy.

 

Routing holes well and confidently (it's a scary tool!) takes practice, and I think anybody would benefit from trying it, sleeping on it, doing more, etc, until doing the critical baffle holes last. I still strongly recommend routing the brace holes before cutting your sheets into the little brace pieces, as clamping them 3 different ways each to cut the holes, then 6 different ways later to round them, would take forever and test anybody's patience. And it would give you that valuable first dip into the experience - there's a lot going on, what with managing dust extraction pipes, wires, direction of cut, swapping hands without stopping, reversing so you don't twist it all, blah blah.

 

Enjoy your evening!

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Thanks Brian, when you say not too deep on the rebate, I’m assuming you mean try to leave more of the cross-section of the side and top/bottom panels showing, framing the front and rear baffles?   I had planned to leave 10mm, as I figured more surface area behind the baffles for gluing.  Also I’ll be wrapping the black vinyl around the the cross section into the inside of the rebate so I may cut the front baffle very very marginally small to leave room for this, so I figured the extra surface area behind for glue will give me a better seal..

 

Good advice rebating deep enough that any mismatch in front baffle against the side panels can be corrected by shaving the side panels.  Though I hope to ge them bang on :)

 

will give it some thought anyway, thanks again for all the advice.

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Ahh, that explains what I didn't understand about the edges. You'll be doing the same fold-over on the backs?

 

Apart from its irreversibility (how do you do repairs to corner knocks? etc), it sounds like a neat solution.

 

1 hour ago, Janus77 said:

hope to get them bang on :)

 

That's what we like to hear!

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Yes same on backs.  My current speakers are constructed this way and they’re still in pretty good condition.  Hopefully no heavy dings!
 

Exterior panels cut!

 

 

E5E87D94-3B62-4474-B839-245342982B67.jpeg

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9BE75402-640A-4CFC-BA49-90BFD6EE3492.jpeg

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I’m finding this whole process very satisfying.  I’m doing a LOT of practice cuts every time I go to do something just to make sure the result is what I’m looking for.   Takes longer than expected but so far the results are shaping up ok, no major F-ups yet!

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Those 45s look amazing. I can't believe you've covered so much, in such a short time.

 

Did the lengths turn out OK? Saw fence at a good right angle, first go?

 

Well done.

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Yes lengths all good.  
I did a practice cut with the stop on the fence perpendicular to the blade (the fence on the rolling bed).   Kept reducing the distance slightly until I had it mm perfect.  Glad I left 10mm on the width and length on my first cuts to allow for trimming. 
 

Widths I found 1mm difference at each end of two of the side panels, I set the parallel fence to the width of the narrower end (which was the width I was aiming for), then flipped the board and shaved the extra mm off.  Maybe the perpendicular fence isn’t 100% straight or the leading edge wasn’t.  In any case they’re all within a hairs breadth of one another now :) 

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5 minutes ago, BioBrian said:

Those 45s look amazing. I can't believe you've covered so much, in such a short time.

 

Did the lengths turn out OK? Saw fence at a good right angle, first go?

 

Well done.

The blade wouldn’t go to 46, I got to about 45.4 by pushing it hard.  
was lucky the instructor tried to help set it up, I told him I wanted 46 degrees and he had a digital mangle measuring tool to check it, but he measured incorrectly (basically the wrong angle, he set it to 44 degrees with the tool showing 46).  Luckily I did a test cut first and when I put the angles up against one another they seemed a bit off.  Checked the saw and realised he’d pulled the angle back.  Corrected it then made my cuts.  
Very glad I checked the settings.  

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6 minutes ago, Janus77 said:

he had a digital mangle measuring tool to check it

 

Haha - reckon I could keep one of those busy for a while...

Glad to hear about all the test runs - keep that up.

If you/they have a table router, those rebates should be pretty quick too - after the testing!

Think I'll have to move back to Melbourne.

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