Phil Starr

You'd need to find the centre of gravity, I haven't got the cab here but I suspect it would be forward of the mid line. Then depending upon the tilt wanted you might need the support at the front. Guitar combos tend to be top heavy.

OK jumping to conclusions again, There's a Falkirk in North Carolina (I think) and the Kodiak Bear is Alaskan. @stevie uses 15mm ply in preference and for bigger cabs 12mm ply needs substantial bracing. I think it'll be fine for this tiny cab though. We used 18mm for the prototype because I had more offcuts of that than 12mm. It's only a matter of balancing toughness, finish, weight and rigidity. I disown all ownership of the early versions of the MK2 and 3 cabs Spruce Ply? Good Grief.

OK not Falkirk in Scotland then I used to work in the building trade for a while, marine as the top grade and exterior with one good face is what I was used to but we have a lot of different materials coming in now with a lot more of it coming from China. Builders are as bad as medics for changing the terms they use for things. Sounds like what you are using would be ideal, just keep the inside dimensions the same. I nearly suggested you send me an off cut Sounds like you know what you are doing. The important factor is to tune the cab. It's tuned the way you tune a bottle when you blow across it where the crucial factors are the volume of air and the dimensions of the mouth. It forms something called a Helmholtz resonator and is tuned to (roughly) the resonant frequency of the speaker. So long as you keep the internal volume the same and the port dimensions identical the tuning will stay the same. Can you get hold of the Fane Sovereign 8-225? if you can't and use another driver I'm happy to see what might work and suggest a new tuning if you need it

Exterior ply in the UK just means the resin/glue is waterproof, ideally you'd want ply that is free of voids and will finish well. To finish well you need a high quality outer veneer but high build paints like Tuff Coat cover a multitude of sins. The ultimate grading of plywood is complex and getting more so over time. I'm quite nerdy about most things and I struggle to keep up. The increase in the use of plywood boards for timber framed houses and other construction uses has confused things a little. If your exterior timber is for construction in that way It's likely to be a bit rough on the outside and likely to splinter when you cut it and may have voids and or repairs to the core plies, so not great. Some of Wickes exterior ply is decent hardwood ply that I use a lot with BB grade exterior veneers. In the end if you build an airtight, solidly made box it will work as a cab though and some people here made their prototypes with exterior softwood shuttering ply and it worked. You can buy a decent piece of ply from B&Q and have it cut to size for less than £20 though so it's your choice. If it's something you use at work why not ask one of the chippies what they think?

Hi Matt, I've been thinking about your problem of achieving an easy to build kickback. I used to have a Hartke kickback the shape you describe. The biggest problem is that you need to cut really accurate 45 degree angles along the long edges of three panels, easy if you have access to a table saw but not something most people can do at home. I also found the Hartke a bit unstable, it tended to roll around in the car and fall back down or onto it's back at gigs. Ok, I'm a clumsy fool and it wasn't entirely the Hartke's fault Anyway I think the problem could be solved with a foldaway flap/strut fixed to the bottom of the cab which would tuck away under some rubber feet when you were carrying the cab or didn't want the tilt back option.

nice job

yes go for the cheaper one

to be fair it might be subjective, I don't use it at home and in any situation where there is the usual audience hubbub the fan just can't be heard. We all perceive things differently. I would also imagine that no two fans sound exactly the same . To produce amps at these prices there are bound to be small discrepancies. I suppose the crucial bit is that I dont really think that the other models will be much different. In these days of internet shopping it could be difficult to compare.

OK we are going for 12mm, the lightweights have it. I'll put up the dimensions for the 18mm panels too so you can build the one you prefer. We should have full plans next week and a cutting list to go with it. I'm going to rake through some of my old pics and put up a 'How To' guide, it won't be for this cab as you'll have to wait too long but it will show all the steps.

Can I ask if we can keep this thread for people who are thinking of building this exact cab or a direct variation of it. I know these threads get used many years after the initial post and there is a lot of patience involved in sorting out essential details when you get to 20+ pages. Many thanks

That's one way of looking at it, I don't want to get into a long debate about bracing but my belief is that it is much more complex than even a good rule of thumb would suggest. It would become a bit of a thread de-rail. There's a difference between opinion and experience. I've built and tried all the cabs I've designed and recommended on BC. I built the prototype for this out of 18mm and panel resonance is not a problem. I doubt that there would be a problem with 12mm ply but I haven't tried that yet. Thinner panels are lighter and bend more easily but these are still small panels, they are also braced all around the edges so I don't think that would be a problem, I've been designing and building cabs for 50 years so that is a bit more than a guess but the proof is 'in the eating'. I'm most concerned about the baffle (front panel) as with two cut-outs the panel is weakened there is no central point to fix to as the speaker is in the way. An 18mm baffle and 12mm might be better for a manufacturer but adds problems in sourcing panels for most people who might build this.

Hi Smanth, can we expect to see this at the next bass bash

I like this a lot. People should feel free to adapt to their own needs. If you have any problems/questions then if anyone wants to ask here I'll do my best to help.

Sorry about the brevity of my answer. I was in the middle of re-jigging the cabinet shape to fit on a smaller sheet of ply to make a cheaper build and as @Downunderwonder said missed the bit about the baffle in between. So, yet that would work but probably isn't the best way to do it. Miss out the baffle and just double the volume and calculate a new port is better. A lot of this design is about the practical problems of packing everything in to a small cab. I'd prefer a bigger port but easily available plastic pipe of the right diameter isn't available. Creating a wooden port would make the build more complex and put people off, I wanted this to be the simplest build possible. If you double up you can use a bigger port and you have to re-tune anyway. If you decide a 2x8 is what you want then you could fit a 110mm soil pipe as a port. 11cm will give the same tuning. the bigger pipe will reduce the chance of turbulence and port chuffing to just about zero. That would give you a 4 ohm, 450W cab capable of 122db continuously capable of matching up with any drummer. You could probably keep the weight down to around 11kg depending upon whatever material you decided to build in. It would be a serious cab

I've been doing a bit more planning for people who want to build this. The original as I've said was built to match the form of an Ashdown combo. There's no need to do that and by tweaking the shape a little I can get the panels cut out of a 1220x610 sheet of ply, the sort that are sold by the big sheds. B&Q in particular offer a cutting service at most of their stores. I can pretty much keep the same shape if I change to 12mm ply, a cute cube that will save a few pounds and a few grammes but the cab may need stiffening with some braces making it a slightly harder build. If I stick with 18mm ply I don't think it will need bracing and 18mm is what we've tried. It will however have to be 54mm taller. My instinct is to go for 18mm in the recommended design and let those who want to save weight work out the bracing for themselves. I think this should be the simplest design possible but with plenty of notes so you can modify if you wish. The good news is that the 18mm ply is £19.97, the batten is £7.37 the speaker £44.22 and the connector £12.50 if you go for the most expensive ready wired version so that is £84.06 for a basic box plus speaker. B&Q will make 5 cuts for free. I've found that if you are nice they don't really count the cuts if they are simple. Does anyone have strong feelings about 18mm v's 12 mm ply

I wonder if there is some manufacturing spread? I would describe my Gnome as whisper quiet and certainly quieter than any other amp I've owned, you should hear my Peavey taking off. At last years SW Bass Bash we looked at all three of the micro amps, we were looking at frequency responses and tone controls so not specifically the fans but I didn't notice any differences at the time.

So just for interest this is a comparison of the frequency response of the 8" cab (in green) with a much bigger cab. It's the 15" driver used in the original Barefaced Super Compact in a 50l cab (Blue). The 8" speaker is bassier than the 15 if you are looking at the fundamental frequencies at the bottom end of a four string bass. Mind you the 15 is a whole 5db louder for the same power

No

This may help you decide which is best for you. It's the bass response of both speakers as calculated by winISD @ 100W. Surprisingly both are equally loud but the 8" cab will handle another 100W at this point, adding an extra 3db, and whilst the 6 handles all of the second harmonic upwards equally well there is a lot of extra fundamental with the 8. In a small room at home the 6 sounds way better than you'd expect, light agile and crystal clear and not as bass light as you'd think. Perfect for not annoying neighbours and satisfying to play. The 8 has a more authoritative sound though and is comparable with a much bigger speaker..

Would it help if you made this your main practice speaker and could store everything else out of sight? If even this is too big there is a smaller alternative https://www.basschat.co.uk/topic/455858-house-jam-micro-cab/

Have you tried driving the amp off the headphone out? I've still got the B1ON and I reckon that would provide 0.775V. FWIW we play back our recorded drumtracks from an iPad headphone out via an active DI. That has improved the sound and we are using balanced line at the earliest point in the chain.

It could be built with 12mm ply or 18mm MDF if you didn't mind the weight. I used 18mm ply because I was matching the Ashdown combo for @Chienmortbb I'd have made it a slightly more orthodox shape and out of 12mm ply if it had been for me. Bracing is always good but the simplest method is to pass lots of bass through the cab and feel for vibration and brace it where it is worst. 18mm and small panels meant this cab didn't need any more than the corner braces that are part of it's construction. I also had a stock of 18mm ply to hand and the original was built during lockdown. John provided the grille so I don't know where it came from. Yes it is plastic drainpipe. I always try to use something easy to obtain for these designs though I have stocks of cardboard tube for some of my own builds. The speaker is front mounted The advantage of building yourself is that you can adapt these designs. Keep the internal volume the same and the port and you should be fine.

I've swapped the pictures on the first post for something that shows the size a bit better, looks like the amp was made for it

Go for it, Some people have also gone for using a car amp module running off a 12V battery. You'd get about 110db which would be plenty for very loud home practice or playing along with acoustic instruments

The thing about a self build is that you can modify it as you wish. You are only limited by your carpentry skills and your imagination. Keep the internal volume and port the same and it's very unlikely you will go wrong. If you decide to go ahead I'll help all I can.