Phil Starr

Hi Al, coincidentally last weekend we put the QSC 12's my band use to the test with some frequency response charts. They are sometimes criticised for their 'harsh' treble and we did measure some problems there. They are still fine speakers but if your RCF 310A's are loud enough for you then with subs they make an excellent system. I use a pair for our duo and as monitors for our band and for an open mic/jam session I used to run. They are really well behaved high quality speakers. There just aren't any sonic nasties there so they can be pushed to really high levels without causing feedback. I've just spent a long weekend this weekend using them for everything for the duo; bass, guitar and two vocals with no backline and they have sounded so good. I'm not a strong singer, plenty loud enough but my pitching isn't secure without decent monitors and these offer the best vocal sound I've ever got from the PA including top quality hired in systems with pro floor monitors. I've never had a better bass sound than I get from these up on poles and the acoustic guitar sounded, well like an acoustic guitar. A pair of these with subs would be a great system but put them in front of the stage if you can and if you have two subs they are better acoustically together as Bill Fitz Maurice has said over and over again. Although I tend to let the practical consideration of stopping drunk punters knocking into stands sometimes override the sound considerations As to crossover why not ask RCF? As a general principle I'd crossover higher rather than lower and as BFM has said a bit of experimentation should guide you. However as a general principle any frequency irregularities related to a compact cab are going to be centred around the 100-140Hz area and excursion limited power handling issues below 100Hz so a 120-150Hz handover of duties looks good to me. The higher the frequency the less power gong to the tops might also be a consideration. But these are general principles/rules of thumb I have no knowledge of the particular characteristics of the subs you are using.

Good news, I had a second look at the Faital last night. the frequency response looks great and the speaker has a longer coil than the Fane with the same magnet gap. I haven't modelled it yet but it looks from Vas and Qts figures to be an OK match for this cab. Maybe even a slightly smaller one. Can you use WinISD or would you like me to have a look

Thanks Steve, that's really helpful. Articulate is a good description and that is exactly what I've found, it's a perfect practice speaker because it brings out your playing but doesn't distract. One reason for this is that you only need a hint of the sub-harmonic bass in most people's living rooms but there are a couple of other things too. A small driver has better dispersion than a large one so in smaller rooms where you are closer and can't always sit straight in line with your amp you'll hear more of what the speaker is doing. More importantly you have a more or less flat response all the way up to 7,000Hz which covers the whole output from the pickups on your bass. No irregularities from a crossover and no need for a tweeter. I initially designed this as practice speaker with a 10-20W amp in mind and something that would boost the sound to the point where I could jam along to a jumbo acoustic guitar. I only tried it with my main amp because, well you have to try your bass with every speaker. It was only then I realised I had something special. I hope you enjoy it with a bigger amp, just remember it's only a 100W speaker

Hi John, you have to look carefully Faital are looking at the coil overhang+ 1/3 of the gap depth as Xmax, I've seen other people use Overhang +1/2 gap depth and some just using the overhang. I think the Fane does this. Also used is the excursion before a specified level of distortion. It's all valid as the magnetic field does extend beyond the gap but for the unwary it can end up comparing apples with pears. Fane and Beyma used to use the less favourable overhang only measurement but with the comparison charts are starting to change to overhang+ Celestion are using overhang only so far. I think Fane used overhang for the Sovereign 6 from memory. Have a look at the top end response also, it's pretty good for the fane. The Faital though gives extra power handling and lighter weight at a price. It's a nice driver though and I'd love to hear how you get on with it if you go ahead

Brilliant, I am pleased you like it, any feedback good or bad would be welcome. I've used the cab again in public this week and it's still doing what it says on the tin for me,

John you've got me thinking, I'm checking out alternative drivers already Shelagh will be pleased! I've been using the House Jam speaker at open mics for the last few days, too loud and a bit bassy at the last gig apparently. Well if they will rush you on with 30secs notice.......

It's not just a had but you might want to look at this https://www.basschat.co.uk/topic/442331-a-house-jam-combo/ coincidentally I revisited it last night, wondering whether to try it at an open mic. The problem is the guitar eq, if you were prepared to tweak that it would be plenty loud enough. If you wanted to start from scratch there are plenty of TDA2020 boards out there and you could run off batteries if you wanted.

Well done, it's great to get to this stage and now you can take an empirical approach of trying things and using that to improve your cab. I like the idea of doubling up the baffle if you are happy with the extra weight. I'm a little worried about that baffle TBH. You have a lot of speaker in a small cab and most of the baffle is cut away leaving it inherently less stiff. Have you just used the bolts to secure the baffle? The foam strip you mention will ensure the cab is airtight but just fixing at the corners isn't enough. At higher power levels the panel will want to resonate and flex. I like a removable baffle but I use screws with a minimum 10cm spacing. That should crush the foam seal and give you a bit more depth for the grille cloth. I'm particularly loving the printed port termination, it looks really good and those small radius cut outs for the port are really hard to do tidily. I'd always go for some wadding on the rear panel and usually do the top bottom and sides as well. Now you have a cab you can add and remove it at will and do listening tests. Keep it away from blocking the port though. You might also want to add some top to bottom and side to side bracing. Again you can do this by testing your nearly finished cab. Well Done

The perfect London cab. You can take it on the tube and at home it won't annoy the neighbours.... well not as much as some others might

You're going to have to do something with that top cab, it's letting the side down

That first try is great isn't it. There's a leap of faith every time you start a project so when you have a working cab it just feels great. Well done. I wouldn't expect it to be boomy, you have a really good motor in that speaker and that will control the cone movement well in that cab. The panels are well braced and it looks like you've built it with care. You've more or less ended up with a Gen1 Barefaced for not a huge amount of money. Why wouldn't it sound good?

Doesn't look far from making it's first sounds

Certainly not! The original Mk1 prototype was a slot ported design. I shelved that (see what I did there ) because I needed a lot of clamps to make it and I wanted something that could be built with the sort of tools people might have at home. The whole point of publishing these designs and running the incredibly long threads is that you are home building and you can either copy the recipe and get the same result of a built and tested design or you can follow the ideas and make something that suits you. We are happy to discuss the likely implications of any changes you propose and that will help de-mystify the whole process. Essentially if the port has the same cross sectional area and length then it will be tuned to the same frequency. We did find in developing the Mk3 that port shape influences how early port noises start to happen. A single large circular port being the ideal as far as port noises are concerned. Turbulence occurs initially at the edges of the port. A slot port however will stiffen the box so you gain and lose something. Turbulence is something easy to get with test signals in the workshop but not something I've experiences noticeably at a gig. If you are building a 2 way design with a horn then I would keep the overall volume of the cab the same.

Good to see you making progress. I have planned projects two years in the gestation, lot's of them! I always liked the philosophy of the Gen1 Compact; take the best driver you can find and put it in a nice lightweight box with a bit of thought gone into stiffening. I like the midrange peak in the Kappalite 3015 and at the time it had few rivals, it is still a nice driver. That's pretty much what you are building and it is going to sound great.

I'm still using the prototype for rehearsals, it does the job really well and it is a nice easy carry. Gig s are few and far between but i've used the 110T twice on it's own. Great for the small awkward pubs but two would be great. It's not like any other single 10 in that respect. My personal preference is for running at monitor levels and going through the PA for the audience and one of these is ideal for that sort of use.

I've always used either the back or the baffle as my removable panels, usually the baffle because I've a tendency to re-use cabs for other projects and often re-cut new baffles. Mind you there's not much you cant do through a 15" hole. I use draughtproofing strip to work as a gasket and get a seal. Good to see it coming together, you aren't far off making your first sounds.

I'm loving the 'leather' covering. I've a little bit of polyester wadding on the rear panel only, there's not a lot of space. I can't wait to see what you think of it once you get the chance to put the bass though it.

It would be good to try them to see what the gain is in terms of port noise reduction and we would share the results here of course. It's a generous offer, thanks.

That's looking really nice, if you fancied sending me a couple I'd love to get to see if it makes a measurable difference, I'd reluctantly return them to you afterwards. I'm sure @stevie would like to see them. He and I have slightly different positions on port noises where he is the perfectionist. Don't let him know but I think he's probably right. A couple of these would help advance an interesting debate. I'd just use the measurement from the outside edges as your length and the inside of the pipe as diameter. The computer software has a set of assumptions for making end corrections for port calculations but it makes a number of other assumptions too for things like leakage from the box. Consequently the calculated tuning is approximate at best (and varies with temperature and air pressure too) so we usually start off with the calculated length and then measure and re-tune. I doubt the manufacturers given parameters for the Scorpions are accurate for a 20 odd year old speaker too. The advantage of your end pieces is that you can cut the tube at will and always have a neat finish. Out of interest what is the approximate cost of making these this way. I have no idea what 3D printing costs.

Hi Adrian I don't know if Chard is too far deep into Somerset for you but we have been wondering if our 110T might be useful to upright players, and I might have other solutions for you too. I've been looking for someone to try our cabs with DB so if you fancied driving across you'd be welcome to try the BC cab, I could probably get one of our BC 12's up here too. You'd be helping me too, amplifying DB poses a number of technical and musical challenges so talking through things with a proper bassist would be a great way to spend an hour or two

The difference won't be in volume it will be in bass response, the bigger cab will give you more deep bass but from 150hz upwards the response and sound will be the same. The smaller cab compensates a little by having an audible response hump around 100Hz which gives a decent bass thump but is perhaps a little less honest. Gigging two of these is extraordinary, as part of the development of the 50l cab I gigged a pair for about 20 gigs. I had a grumpy drummer at the time and he asked me to crank up the bass as he 'couldn't hear it' (it was well balanced out in the audience area/FOH) for one gig I did crank it and at the end of the first half he had a different complaint 'I couldn't hear my effing snare drum'. Well he never complained again As to adding a tweeter, well that has two advantages, ours is designed to flatten out the response so what you get is the sound of the bass and any fx/tone shaping you choose to apply. The second advantage is in the radiation pattern, big speakers 'beam' the midrange and upper frequencies so that what you hear and what the audience hear are different and with a single 12 you'll be missing out on a lot of the mids and tops unless you angle the cab to point at your ears. of course if you stack two then the top cab will be nearer ear level so this is less of a problem. In contrast the single speaker gives a character of it's own. The 12CMV2 has a rising upper mid peak like most 12" speakers and with the bass peak at 100Hz it has an inbuilt 'smiley face response' which is pretty much what a lot of us dial in or get naturally in a lot of commercial cab designs. One solution of course is to build one with a horn one without. You then have three options; a full range cab flat response cab, an old school sounding 1x12 and a stack with both honesty and a really authoritative sound. Another option is to start with a simple 12 but leave space to add the horn later and do that as a separate project. I designed the 30l cab for smaller venues. You do lose some bottom end and frankly in small pubs that's really useful, in big/ open air venues not so much, in the end I used it for nearly everything though. Why carry something big when a small cab will do everything you want? Every one of these speakers is going to be loud enough to keep up with a drummer with a 300W into 8ohm amp and because the drivers have been chosen for good excursion they will handle that power comfortably. Two of the 50l cabs will overwhelm the rest of the band if you want, but why would you do that? Hope this helps

Curious about the Stagepas so I've just had a look, it's a bit of an outlier with 1.5" drivers in the column compared with most others which are using 3" or even 4" drivers. The problem is a lack of output 119db is claimed compared with 124db and 129db for the Stagepas 400 and 600. Your Mackies probably have a similar output to the 600's depending upon which ones you use so the Stagepas 1k is a lot quieter than your current PA. I don't think this is a potential band PA if you are going out with a drummer. There are loads of other systems out there which are more capable volume wise, no criticism of Yamaha. I'm a long time user and these probably sound fab but not as a band PA. I have to say I'm a big fan of the column systems though, I've heard the RCF Evox sounding great and had a chance to have a good listen to the MarkAudio Ergo at the South/west bass bash a couple of years ago and that sounded great too. I've played in a band with the LD Maui 28 and that was good too. The Bose though isn't really loud enough to be usable for a band IME

Hope the gig goes well tonight, (though given the time difference I should say I hope it went well. You are probably just finishing ) Looking forward to hearing how the cab sounded. It looks great.

I love the way you've made this cab your own, and if I had that amp then that is the way I would have gone. It's a shame other bass amps don't offer bi-amping in this way. That's a lot of punch in a lightweight very portable cab. I hope it gives you years of pleasure.

John @Chienmortbband I have been looking at drill batteries too. You can get higher voltages than a car battery and they are a lot lighter. I was looking for a 18-0-18 supply for a Chinese amp module and I have a couple of De Walt 18V, I never got round to trying them though. The car amps looked a simpler route.