Speaker Build-Cheeky Monkey

they look pretty impressive, will give the batons a try and see how things turn out

REW software installed on my Mac this evening so will see how things turn out and give this a go

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Thanks for the tip, yes, had gone with the Mills as part of the plan so at least I know I’m heading in the right direction

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If you glue and screw into the battens, as I did, it creates a problem. The wood is likely to shrink marginally over time, as it dries out indoors. So even if you’ve countersunk the heads of the screws and filled over them, they pop up. Years ago I built Malcolm Jones’s “Tabor” design, all the edges glued and screwed with battens, and veneered them. They looked really nice until lines of bumps appeared as the screw heads started to push up. I’ve had it happen with chipboard, mdf and best birch ply. The ones in the picture were sanded flush when I built the box. The skin of 6mm mdf over the boxes solves the problem, but that’s quite a long and heavy route to go down. An alternative is to glue the edges, use screws to clamp the joins, and take any external screws out when the glue has set. Or don’t fill over them, and leave them a number of months before tightening them again. It all depends what kind of finish you want when you’re done - I prefer veneer, not just for the look but because it adds another layer of a different density material to damp out resonances. Some purists veneer on the inside too!

Just note that that cabinet was not build according to the original designers spec. It should have had bracing!

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that’s really useful, I’ve used screws to secure the rear baffle while the glue sets and will remove them knowing this

thanks

Drivers arrived today so will start work on the front baffle tomorrow, crossover components on order tonight so hoping to have something to test up and running next week

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This looks like an intriguing project - good luck with the build.

I agree that bracing/making a cabinet that large more rigid would be a good idea. Assuming you have not yet put the front baffle on, one or possibly two window type braces might be a good idea if you thought battens might be fiddly.

Ref the design, do you know the crossover point/HPF you plan to use for the tweeter? From what you are saying, you plan to run the woofer wide open with no filtering in the high range. Speaker design involves trade offs. On the one hand, your design makes things electrically more efficient with a direct link between woofer and amp - this should give a ‘real’ and vivid sound.

On the other hand, a large woofer will beam relatively early frequency wise - this means the HF output of the speakers will be quite focused rather than spread through the room. Your tweeter will help alleviate this but if you cross too early you may have phase cancellation issues.

I have built an OB system and have just added rear firing tweeters to the 8 inch full range drivers - this has really extended the HF output. I was careful to match the efficiency as closely as possible to the FR driver (which runs full range with no HP filtering). Making the tweeter rear firing helped to deal with any phase cancellation issues. I used off the shelf Audison car audio tweeters with built in crossovers. The rest of the system is completely active with two more stages of woofers culminating in 15 inch OB Biancos for the lowest bass. Even with relatively lowly main amplification (an Arcam A18) the system sounds massive thanks to its OB nature and large number of actively driven woofers.

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Thanks Alex

I think I’ll be adding a brace (or two) after all once I have the speakers in the front baffle and work out where everything needs to sit for clearance

Your project sounds interesting, has it featured on any of the threads on here? I’m particularly interested in the fish others have applied to their self builds, conscious this could d make or break the visual appeal which may help household harmony. These are big boxes after all…

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This is the original build thread:

I have updated the design since (including adding a second Bianco 15) so, when I get an opportunity, I will produce an update.

Regards
Alex

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This is what the system looks like now. For scale the TV is a 65 in model. All the electronics reside in the TV cabinet.

When not in use the main speakers can be moved back to the wall. The Biancos can be unplugged and fit neatly behind our sofa.

I’m still deciding on the final angle/position of the tweeters - when I have done this I will use something more attractive than Blutak to secure them😁. I’ll also sort the wiring too. Their original crossover has a HP at 3.5khz with a 12db slope. As I say, the full range drivers (SB Acoustics 8 inch full range) have no filtering at all.

The drivers below them (2 x 8 inch SBs per side wired in parallel into 4 ohms) are powered by the front channels of the Genesis - they are low passed at circa 180hz.

The SB Biancos are low passed circa 95hz - they are in parallel into 4 ohms and run bridged mono by the rear channels of the Genesis. The gains on the genesis are set low for both speaker sets but particularly the Biancos (they are 98db efficient each and this increases when wired in parallel!).

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Yep that woofer will breakup as frequencies increase…I think run the tweeter as low as possible…hopefully down just below 1500hz…then roll that big drive unit off to suit…to get flattest response…the lower the tweeter can go the better.

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@chris5 I wonder if you made any progress in the meantime… Good luck!

yes, small steps

I made a decision on the veneer (Indian rosewood for the front and black stained oak for the back and sides) and have added to the front baffle, cutting the holes for the drivers too

I also did a little more research on the speakers which inspired my build and as they aren’t braced am sticking with my oriringal plan to mirror the design

Finally decided on the crossover component, internal wiring and other ancillary items but I’m out of the country on business next week so the week after that I’m hoping to crack on with more work on them

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The veneer looks great - did you oil it or treat it otherwise?

Thanks

Nothing on there yet, to be honest I was so happy with the way the veneer went on I had to see it with the drivers in there and mocked tis up in the garden while I had 5 minutes spare

I’ve got some liberon finishing oil that I’ll be applying once everything is together and the rest of the veneering completed, will post more pics as I progress

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