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2.5 way Beyma TPL150 AMT with dual 8 inch SB Acoustics


Guest atilsley

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Guest atilsley

Very room-friendly and wonderful design featuring:

 

- 24mm Euro Birch ply panels, plus uber bracing (2 of 3 shelves shown in pic)

- carefully mitred baffle, sides and top to create integrated look and narrow baffle

- 10mm cotton deadening plus acoustic foam

- LR2 custom high-grade xover from Redefy Audio (Henry)

- Beyma world-class TPL150 Air Motion Transducer tweeter and matching horn

- Dual custom SB Acoustics 8 inch woofers (modified by Redefy Audio)

- slot porting of cabinet to perfectly match woofers and cabinet sizing

- dims 1100mm tall by 270mm wide by 420mm deep

- quality gold terminals and up-spec cable (TBC)

- finish in gloss two-pack poly

 

Anticipated sensitivity around 95dB.

 

A nice project, with great potential.

 

Andrew

front dry run.jpg

brace shelves.jpg

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Guest atilsley
On ?29?/?04?/?2017 at 8:06 PM, Faceman said:

2.5 way, right?

Sent from my SM-G935V using Tapatalk
 

Yes, I'll config the xover to limit the lower woofer's upper freq.

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If you're going 2.5 way then the woofers should be in separate compartments otherwise you'll probably get out-of-phase rear wave midrange radiating out through the low woofer. Plus, separate woofer compartments give you more bass tuning options.

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Guest atilsley
2 hours ago, Weka said:

If you're going 2.5 way then the woofers should be in separate compartments otherwise you'll probably get out-of-phase rear wave midrange radiating out through the low woofer. Plus, separate woofer compartments give you more bass tuning options.

Thanks, that's good feedback. 

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Probably not a big deal, but did you consider doing the bracing shelves with the ribs running diagonally rather than from the middle of each side? It would have effectively made 4 triangular cutouts instead of 4 squares, which, theoretically at least, would be more rigid... Looks like a great project!!!

Sent from my SM-G900I using Tapatalk

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10 hours ago, atilsley said:

2.5 way

 

Putting the woofers in differently tuned enclosures is unlikely to be a good strategy.   You want them to have the same low frequency motion - which with differently tuned boxes, and a passive filter.... they won't.

 

8 hours ago, Wiffle said:

It would have effectively made 4 triangular cutouts instead of 4 squares, which, theoretically at least

 

In this situation what you are looking to do, is attach the most unsupported cabinet panel area (ie. the middle of the sides), to as many other cabinet surfaces as possible, so in this case the cross (with the centre of the cross also connected to something - it looks like hes going to have some vertical braces in there) is the best plan.

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In this situation what you are looking to do, is attach the most unsupported cabinet panel area (ie. the middle of the sides), to as many other cabinet surfaces as possible, so in this case the cross (with the centre of the cross also connected to something - it looks like hes going to have some vertical braces in there) is the best plan.

Ok, that makes perfect sense; thanks Dave [emoji106]

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Guest atilsley
16 hours ago, Wiffle said:

Probably not a big deal, but did you consider doing the bracing shelves with the ribs running diagonally rather than from the middle of each side? It would have effectively made 4 triangular cutouts instead of 4 squares, which, theoretically at least, would be more rigid... Looks like a great project!!!

Sent from my SM-G900I using Tapatalk
 

Yes, I consudered this.  Chose square patten to ensure no restrictive volume for air glow. 

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Guest atilsley

Agree with Dave re not building separate bass compartments. Important to have consistency of bass, while still able to make drivers perform at slightly different freq. 

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10 minutes ago, atilsley said:

Agree with Dave re not building separate bass compartments. Important to have consistency of bass, while still able to make drivers perform at slightly different freq. 

 

Separate enclosures is ok ...... but separate enclosures tuned differently isn't a good idea .....   unless you would correct the response of one driver so the two drivers maintain the same LF response - but this is impractical with a passive filter.

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Guest atilsley

Port shelf added, with rounded edge.

 

"floating" platform added underneath cabinet, edges to be painted flat black.

 

 

bass platform.jpg

port shelf.jpg

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Guest atilsley

Starting on the felt...boy, this is hard work...about 15mm thick.

 

Rear panel commenced first, showing where triple terminals will be located (off-board xover boxes, with 3-way separate wiring).

 

 

felt rear panel.jpg

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Guest atilsley
1 hour ago, Sub Sonic said:

@atilsley have you tried used packing tape instead of masking tape? You can stretch it a little when applying it and it helps pull the joints together.

 

Regards,

 

SS

Yes...it is beneficial in that way....but doesn't stick as well, especially when dust etc around.

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Guest atilsley
9 hours ago, Faceman said:

Even with perfect CNC joints, I still prefer clamps. You can never have enough of them...

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Agreed...the caveat to that is when you're building mitre joins, where too much pressure simply pully the mitres apart. This is why I build the cabs in stages...using tape to secure the panels. By the time I add braces and poly glue, the unit is rock solid.  

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Guest atilsley

I'm buggered.....

 

This 20mm felt (yes, I said 15mm earlier) is very hard to work with. Bought upgraded knife and blades.

 

All done...phew.

 

 

felt in.jpg

felt cutting.jpg

felt 20mm.jpg

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Guest atilsley

Ye Olde Bees Wax tested on one top panel...happy with that.

 

Drivers fitted temporarily on one.

 

Six pairs of Supratek wires made up, with silver ends.

 

Six pairs of gold coated heavy terminals.

 

Xover boxes will have corresponding six pairs of gold terminals, plus gold input terminals.

 

 

wires up close.jpg

terminals.jpg

stained top.jpg

drivers in one.jpg

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Looking good, nice drivers the SB acoustics, interested to know what change your planning on doing to the drivers

to improve them? extra magnet? more weight? 

 

 

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