New Build: BC 112mk3

[chyc]

Had the timings been slightly different I may have purchased a LfSys bass cabinet, but I'm currently having a lot of fun building the BC 112mk3.

 

Some things to note, in comparison to the BC110T cabinet which you may see photos in another thread:

 

1. It is a significantly harder build than the BC110T. The tolerances are tight and there is not much margin for error. The battens round the edge of the BC110T proved invaluable to affix panels.
2. The parts are harder to source. Even the wood, being of the 15mm variety, required me to search online whereas 12mm can be found in B&Q and Wickes.
3. Clamps are essential, including great big fat ones as seen in the photo

 

I don't own an LfSys, but as everyone knows round here, bass gear can be judged by pictures alone so that's what I'm going to do. The LfSys looks to have groove joints, presumably to save on weight and increase the inherent strength to the build. There is absolutely no way I am capable of making such joints. Secondly, the circular cut-out for the port I did with a jigsaw. I did the best I could but it's not perfectly circular so when I do install the drainpipe it's going to look a little messy with caulk round the edge. The LfSys looks to either be CNC'd or cut using a hole saw so the port tube looks very professional. When it comes to cost, yes this is a saving over a Silverstone, assuming you already own the woodworking tools. Using the back of an envelope calculation I think I spent around £400 on parts, although I see that the 12PR320 has gone up a fair amount since I purchased it, and I bought cheap 15mm hardwood.

 

Anyway, onwards to victory! I have a panto in January (oh yes I do) so I have that as an ambitious target to get this ready. I haven't decided what colour this is going to be. Orange tolex with a red baffle may cause the universe to implode, so that's tempting.

 

 

[Phil Starr]

You have made a great start.

 

You are right about the difficulty of building this way, @stevie did produce a 'flatpack' kit for the first 10 or 20 people to build theirs and that's what all the pics show. All the parts were CNC routed. All the other BC designs have cabs I've deliberately designed to be 'easy build' in that they need no clamping or specialist tools other than a Jig saw. I always use a reinforced butt joint screwed and glued inside the cab, which is stronger and needs no clamping so is easier for people without woodworking skills. It was my intention to build a Mk3 using this technique and to publish the simpler cab but that never happened. If anyone wanted to there is no reason not to build this cab using any method they want so long as they keep the internal dimensions the same. 

 

Now he tells me

 

 

 

 

[chyc]

Now that @stevie has announced it officially as a service, I feel free to say that I was an early beneficiary of the crossovers he sells. The crossover arrived promptly and was very competitively priced. I must say this is what convinced me to try the BC112mk3 over another competing design that I was thinking about. It arrived without the caulk: that butchery was me.

 

 

 

Going back to the port hole, it came out better than I thought, but still not perfect. It's got caulk on the other side of the baffle so is airtight. If I feel moved to I may use wood filler later which is more amenable to painting, but I do like natural wood and filler tends to stain.

 

 

Here is the last side panel going on. The wool cool has gone in and is looking fabulous.

 

 

One advice I can give is to purchase TiteBond Premium over EvoStick. I cannot say whether one is a stronger bond than the other, but the former has the massive benefit of having a far superior applicator which makes spreading it easier, and stops it drying out when it's closed (it presses out the remnant on closing: genius).

 

[chyc]

On 31/12/2022 at 08:20, Phil Starr said:

If anyone wanted to there is no reason not to build this cab using any method they want so long as they keep the internal dimensions the same. 

 

Now he tells me

 

 

 

 

ARRRGGGGH.

 

Lol, just kidding. Sometimes it's the journey rather than the destination that's the reason for going somewhere, as it is in this case.

[Phil Starr]

How's the build going?

 

[Phil Starr]

On 01/01/2023 at 17:56, chyc said:

One advice I can give is to purchase TiteBond Premium over EvoStick. I cannot say whether one is a stronger bond than the other, but the former has the massive benefit of having a far superior applicator which makes spreading it easier, and stops it drying out when it's closed (it presses out the remnant on closing: genius).

I cleaned out my titebond bottle and now re-use it with whatever glue I'm using it is a great design.

[chyc]

14 minutes ago, Phil Starr said:

How's the build going?

 

It goes in fits and starts. I'm actually building it at my parents' house so was able to get a fair bit done. All sides are in, as is the wadding. The top needs to go on, but there's about 1mm discrepancy in the height of the four walls. I will need to take a plane to a side before I am able to put the last side in. I'm now back home but will update as soon as I can.

 

I've been in correspondence with @GlamBass74 who has been an immense help and support to me in this and the BC110T builds. One thing that I was going to blindly do (and may still do) is use wood screws to drill in the woofer. I figured that it was light enough and I wasn't going to be taking it in and out once everything was build. However, he did suggest reinforcing the inside of the baffle with either a ring or small strips of spare ply. I didn't do it for my BC110Ts and the wood screws barely poked out the other side, but for the heavier 12PR320 is it a necessity?

 

 

[Mykesbass]

On 01/01/2023 at 17:56, chyc said:

Now that @stevie has announced it officially as a service, I feel free to say that I was an early beneficiary of the crossovers he sells. The crossover arrived promptly and was very competitively priced. I must say this is what convinced me to try the BC112mk3 over another competing design that I was thinking about. It arrived without the caulk: that butchery was me.

 

 

 

Going back to the port hole, it came out better than I thought, but still not perfect. It's got caulk on the other side of the baffle so is airtight. If I feel moved to I may use wood filler later which is more amenable to painting, but I do like natural wood and filler tends to stain.

 

 

Here is the last side panel going on. The wool cool has gone in and is looking fabulous.

 

 

 

One advice I can give is to purchase TiteBond Premium over EvoStick. 

 

Thanks for this - can't tell you how many times I've gone back to find an unusable bottle of the latter! Will get some for my woodwork projects.

[Phil Starr]

10 hours ago, chyc said:

 

It goes in fits and starts. I'm actually building it at my parents' house so was able to get a fair bit done. All sides are in, as is the wadding. The top needs to go on, but there's about 1mm discrepancy in the height of the four walls. I will need to take a plane to a side before I am able to put the last side in. I'm now back home but will update as soon as I can.

 

I've been in correspondence with @GlamBass74 who has been an immense help and support to me in this and the BC110T builds. One thing that I was going to blindly do (and may still do) is use wood screws to drill in the woofer. I figured that it was light enough and I wasn't going to be taking it in and out once everything was build. However, he did suggest reinforcing the inside of the baffle with either a ring or small strips of spare ply. I didn't do it for my BC110Ts and the wood screws barely poked out the other side, but for the heavier 12PR320 is it a necessity?

 

 

It's good to see you and @GlamBass74are sharing tips. I can't tell you the number of people here who've helped me over the years.

 

Most of what I build are prototypes, I like the design and testing process and I'm naturally restless. I frequently cut corners and many of my cabs start life with speakers just screwed in. I've had the odd screw loose (!) but never had a speaker come loose and rarely had a rattle. The idea is that I would always replace the screws with T-nuts but sometimes that takes months or years  I tend to use 18mm hardwood ply though. Poplar ply is softer and if you have 12mm poplar then sticking a little square of wood for the screw to sink into would be better. I guess my 'official' advice would be why not screw the speaker in place so you can test it at home then use the screw holes as guides for drilling out to fit the T-nuts before you start carrying it around.

[Chienmortbb]

On 01/01/2023 at 17:56, chyc said:

Now that @stevie has announced it officially as a service, I feel free to say that I was an early beneficiary of the crossovers he sells. The crossover arrived promptly and was very competitively priced. I must say this is what convinced me to try the BC112mk3 over another competing design that I was thinking about. It arrived without the caulk: that butchery was me.

 

 

 

Going back to the port hole, it came out better than I thought, but still not perfect. It's got caulk on the other side of the baffle so is airtight. If I feel moved to I may use wood filler later which is more amenable to painting, but I do like natural wood and filler tends to stain.

 

 

Here is the last side panel going on. The wool cool has gone in and is looking fabulous.

 

 

One advice I can give is to purchase TiteBond Premium over EvoStick. I cannot say whether one is a stronger bond than the other, but the former has the massive benefit of having a far superior applicator which makes spreading it easier, and stops it drying out when it's closed (it presses out the remnant on closing: genius).

 

The Everbuild Adhesives also have a superior tip to the Evostick ones. However, having studied Adhesives, there is very little difference in the glues. Some are biased to fast drying, some for longer free time, but all are "stronger than the wood itself". If you want to be picky, the non-waterproof ones are stronger.

[Chienmortbb]

2 hours ago, Phil Starr said:

It's good to see you and @GlamBass74are sharing tips. I can't tell you the number of people here who've helped me over the years.

 

Most of what I build are prototypes, I like the design and testing process and I'm naturally restless. I frequently cut corners and many of my cabs start life with speakers just screwed in. I've had the odd screw loose (!) but never had a speaker come loose and rarely had a rattle. The idea is that I would always replace the screws with T-nuts but sometimes that takes months or years  I tend to use 18mm hardwood ply though. Poplar ply is softer and if you have 12mm poplar then sticking a little square of wood for the screw to sink into would be better. I guess my 'official' advice would be why not screw the speaker in place so you can test it at home then use the screw holes as guides for drilling out to fit the T-nuts before you start carrying it around.

I only put this up for discussion, but if you used a suitable block of scrap wood behind the screwholes, together with eight reasonably large screws. That would hold the driver firmly in place without T-Nuts or threaded inserts. I have tried all three methods, and both T Nuts and threaded inserts are less than ideal.

[Aidan63]

1 hour ago, Chienmortbb said:

 and both T Nuts and threaded inserts are less than ideal.

in what way less than ideal, in your opinion ?

[Chienmortbb]

3 hours ago, Aidan63 said:

in what way less than ideal, in your opinion ?

I have built cabinets where both have come adrift, and then you have a pig of a job to get the driver in/out. I have a loose rattling insert on my After Eight modded combo that I need to fix now, but in all honesty I have had more trouble with T Nuts. A No 10 wood screw can hold 35Kgs minimum, into wood, so 4 give you 140Kg withdrawal force. 8 would give you 280 Kb.

 

Of course, an M4 or bigger, machine screw holds much more. However, the T Nut is an interference fit into the baffle but, unlike a nail, does not have a parallel shank. So does not resist a backward force well.  Threaded inserts threads do not always align well with the plys of the plywood baffle.

[Phil Starr]

Sometimes I worry about how my mind works. I love this sort of discussion 

 

I don't think there is a problem free way of fixing a speaker to a cab. All the regular methods are problematic in some way. You start with fixing holes which are often around 6mm from the speaker cutout with a 5mm hole drilled to take the fixing. that leaves you 3.5mm of 'wood'  to  prevent any sideways movement. Less unless you've cut both your cutout and drilled your screwhole perfectly.  After you drill a hole the wood fibres, released of pressure are going to expand a little and close the hole, that's why you can't just slide the T-nuts in or why your Rawlplug needs hammering in. If you are using plywood you will have unseen voids which will mean some of your screw is going into air, not wood. Not all timbers are equal, some species are a lot harder than others. Fast grown poplar is softer than many timbers, oak famously hardens with age, the moisture content affects hardness as does the part of the tree the wood is taken from and so on. If you are dealing with plywood most of the time you have no idea what the inner plies are. A lot of 'poplar' ply is actually Eucalyptus internally and even the outer veneer is a Chinese poplar. Baltic birch is often only birch on the outer layers and if it comes from Kaliningrad it is probably from trees grown in Russia (which may be fine of course, it's a big country)

 

I quite like t-nuts, you are pulling them up towards the speaker frame with the baffle sandwiched in between The shape of them spreads the load a little and if you have a weaker piece of wood underneath it is still going to hold. Your bolt is in a metal thread so it's way stronger than it needs to be and you are going to have no problem removing the bolts unless it all rusts. The downsides are the appalling quality of most T-nuts with poorly sharpened prongs at well off 90 degrees and poor thread cutting. They can be quite big so the diameter takes them right to the edge of the cutout and the prongs break the edge or even stick out past the edge. After losing one or two by pushing too hard on the bolt I now don't push too hard and I don't cross thread then because if they are tight with my fingers I stop and investigate. I don't hammer them in either, not on a speaker mounting I use a washer and tighten the bolt against it and pull them in, 

 

Screws are great in that they are quick and easy. you need a pilot hole if they are close to that fragile edge, even if they say they are self drilling you are going to get some expansion when they go in and a couple of mm of ply won't take that. Every now and then one will slip and pull out when you tighten it, all that variable wood or lack of wood. I just drill out a bigger hole and use a Rawlplug. I've never used a threaded insert, though I've come across them in commercial cabs. They seem to work.

 

The biggest lesson I've learned is that you need to drill the right sized hole, at right angles with the right drill bit and properly centred. Use a brad point bit They are much easier to centre and they are self guiding , cut a much cleaner edge and clean out the sawdust effectively. Ordinary twist drills are much harder to centre and often wander off when you start to cut, in something as soft as timber it's really hard to stay square and you can easily end up with a slightly oval hole with rough edges.

 

Don't pooh pooh the speaker clamps either, the metal L shaped brackets. Ugly as sin but that's not a problem if they are under the speaker grille and are painted black. By moving the fixing point away from that soft edge you have a much better chance of a nice firm fixing. I use them a lot when developing a new speaker as getting the speaker back out is simple with less chance of sticking a screwdriver though a nice new speaker

 

That all makes it sound difficult but it really isn't, just take a little care and it'll be fine.

[3below]

^ solid good advice above (much of which I learned the hard way pre BC cab builds).  In an ideal world speaker chassis would be designed differently   too late now, tradition has the grip.

[JohnDaBass]

@chyc when you complete your project could you post a sonic review of your handywork?

Could you compare your achievement with other cabs you have used? 

[chyc]

2 hours ago, JohnDaBass said:

@chyc when you complete your project could you post a sonic review of your handywork?

Could you compare your achievement with other cabs you have used? 

You can count on it!

 

A word of warning though: my kit can be politely described as niche, and mainly geared towards double bass and lightweight cabinets.  I'm also incredibly lax about my sound, so long as I can hear myself.

[Phil Starr]

Wondering if you have made any more progress on this?

[chyc]

1 hour ago, Phil Starr said:

Wondering if you have made any more progress on this?

Afraid not. It's being built at my parents' house with all the tools, a fair distance away from where I live. That's why it's always so slow progress with me Hoping to visit next week (half-term) and most likely I will be able to get some sound out of it then. Really cannot wait!

[chyc]

It's the final straight. Last panel glued down and drying now.

 

 

I've made my first major boob unfortunately. If you've made the cabinet before you can probably see it just by looking at this photo:

 

 

Basically I didn't like the vertical mount of the rear panel, so I rotated it. Now unfortunately I cannot put the rear brace up the back panel without interfering with the connector plate. Bummer

 

Not to worry, I'm unlikely going to be playing anything heavier than Neil Sedaka so I just added a noggin that dangles just above the plate.  You can see it in the photo above.

 

I have tins and tins of seriously out of date paint. I'm going to open them up and see what options I have on the colour front. This was supposed to be the experimental build using uber cheap wood, but to be honest while I didn't nail everything first time, it's turned out pretty well, and I'm sure it will become a perfectly usable cabinet; this may well be my last build!

 

The wood was atrocious though. Voids galore.

 

[chyc]

 

Initial thoughts: like the BC110T I think its highs are a little veiled.  Do I need to wait for the speakers to loosen up? I would have thought that waiting would give me more bass rather than more treble, but I'm no expert. In terms of as a bass cabinet, I can totally hear stuff through this cabinet that doesn't come out the BC110T. There's an authoritative thud (not boomy I hasten to add) for kickdrum and low bass. That may be your jam, but I'm not working in those genres and I have to admit that the BC110T with its smaller size, and particularly its lower weight, is a better fit for me personally. I will say that the BC112mk3 seems to have better dispersion in the sense that I can sit on it and can hear what I'm playing. This may prove incredibly useful as the cabinet is the perfect height to sit on while playing a double bass.

 

By no means am I disappointed with this cabinet: it sounds great with a bass and maybe I can grow to love it as a general purpose noise maker. I'll report back in a month or two once it's bedded in, but as things stand, I think the 10" speaker is better for double bass.

 

I will have to post later about my experiences with a planer and sander. All I can say is that cheap wood and planing and sanding do not mix at all, and I have become quite an expert in wood filler as a result

[chyc]

If you notice I changed the model of horn. That was for the simple reason that the one in the design was out of stock when it came to ordering. I understand that this changes phase and dispersion so with my mk3 that may be the reason the highs are a little muted. I picked the horn that explicitly listed compatibility with the Celestion CDX1-1415. It was never my intention to make it look like a Monaco, and as it so happened I took so long the horn came back in stock again. Doh!

 

Now, the planer. Firstly I have to admit this was my first time in this so there was some pilot error, but definitely the wood didn't help. Both the planer and the sander seemed to latch onto loose ply and use that to rip up the fascias on some of the panels. There was none of that with the nice Baltic birch. Again, wood filler has saved me.

[JohnDaBass]

Nice work, great job, thanks for sharing. 

[BlueMoon]

3 hours ago, chyc said:

I picked the horn that explicitly listed compatibility with the Celestion CDX1-1415.

I have the same issue with the P Audio horn being out of stock, seemingly everywhere. @chyc which horn did you eventually use?

 

Nice work overall and thanks for sharing your experiences.

[Phil Starr]

22 hours ago, chyc said:

 

Initial thoughts: like the BC110T I think its highs are a little veiled.  Do I need to wait for the speakers to loosen up? I would have thought that waiting would give me more bass rather than more treble, but I'm no expert. In terms of as a bass cabinet, I can totally hear stuff through this cabinet that doesn't come out the BC110T. There's an authoritative thud (not boomy I hasten to add) for kickdrum and low bass. That may be your jam, but I'm not working in those genres and I have to admit that the BC110T with its smaller size, and particularly its lower weight, is a better fit for me personally. I will say that the BC112mk3 seems to have better dispersion in the sense that I can sit on it and can hear what I'm playing. This may prove incredibly useful as the cabinet is the perfect height to sit on while playing a double bass.

 

By no means am I disappointed with this cabinet: it sounds great with a bass and maybe I can grow to love it as a general purpose noise maker. I'll report back in a month or two once it's bedded in, but as things stand, I think the 10" speaker is better for double bass.

 

I will have to post later about my experiences with a planer and sander. All I can say is that cheap wood and planing and sanding do not mix at all, and I have become quite an expert in wood filler as a result

I wouldn't have thought that you'd be hearing more treble after breaking in the speakers.

 

The BC 112 mk 3 is essentially a proper FRFR bass speaker. The bass driver and wooden cab will handle bass better than almost any PA speaker and the frequency response has no nasty peaks or troughs. That makes it very different in it's sound from most bass speakers which will have a peak in the upper mids which is in the top end of a bass. You would need to re-eq for this speaker in all probability. I suspected the 110T would be good for DB, the extra volume and extra low frequencies are going to lead you potential feedback resonance problems but the gentle early roll off of the 110 would help with that. Try rolling back the bass on your amp with the Mk3 and see how that sounds.

 

We've all got very used to the coloured sound of our normal bass speakers and when you first listen to the clean sound of your bass through a flat response speaker it is somewhat underwhelming at first. You will really miss the artificial colour of a traditional bass speaker. Then  when you hear the extra details you'll start thinking 'OK yeah I get that' but you will still miss what you have lost. For me it was only when i realised i was in charge and started resetting the tone controls that I gained confidence and started enjoying the flexibility. I'll be interested what you think in a months time. you probably need to gig and rehearse with it a little

 

On the other hand the 110T is a little gem, I've not fallen out of love with mine and it is such a practical solution for my needs so long s ultimate volume is not the issue. I still use it a lot.