Phil Starr

Well the two eights are just about the same area as a 12" driver. It's possible with a single 12 to create 120dB @ 1m which is roughly as loud as a drummer so it is also possible that these two eights will produce the same level. The manufacturers claims are all about maintaining the 'sound' of bigger cabs. Again technically this is not a problem my 5" hi fi drivers have no problem reproducing the 32' pipe organ sounds on some of my records, far lower than anything a bass will do. The problem is in doing loud and deep with small speakers. It's just about possible with a single 12 or 2x8 so you'd need to check it out, they have one in Mansons in Exeter if you can get down there. Listening to the sound on the website they sound pretty good but I would say characterised by an open top end rather than deep bass, which is much as you would expect from 8" speakers. the only way to resolve this is by listening.

Water based will penetrate too, actually I think it's a mixture of water and alcohol but I don't suppose that is important.. I'm guessing at the finish you are after but it sounds as if you want something like a 'limed' effect but black not white. Lime is applied as a paste and because it is made of particles not dissolved pigment it won't penetrate but sit on the surface and in the grain. Then if you sand back it exposes the wood but leaves the white in the grain. Nowadays people use liming wax or even eggshell paint to achieve the effect. http://voices.yahoo.com/how-create-aged-effect-liming-wood-2549318.html You might be able to do this with black paint.

I'd be pretty careful about this, Spirit based wood dyes penetrate a long way into timber and Ash is quite porous, you won't be able to sand it out. Practice on some scraps of ash first. If you don't have any Yandles have big boxes full of off-cuts which they might post to you http://www.yandles.co.uk/ .

To be fair it is also a nonsense as a design. Given that the distances between the speakers radiating surfaces is in the 10-70cm range and the angles less than 30[size=4] degrees, where off axis response is only going to be a few dB down it will pretty much have all the comb filtering problems of a 4x12 over the midrange. Only very high frequencies (high for a bass anyway) are likely to be directed towards the bassists ears. [/size]

Big apology to all those following this, I've joined a new band and have new set list to learn and bass playing is what it is all about. My aim was to summarise about a weeks worth of discussion per post but I'll have to condense that a little to catch up. When I left it we were starting to look for a good driver (the actual speaker) for our cab. I won't pretend it was an unbiased search. Stevie was keen we look outside the usual suspect (Eminence) I had previously done the search and bought a couple of Beymas. Celestion and Faital were mentioned early on. Technically we had some design specs to meet. We decided it was practical to make a single 12 capable of matching a drummer which meant achieving 120dB @ 1m within its maximum power. Most 12" speakers handle around 300W so that means something like 95dB/W efficiency. We also decided a practical 1x12" needed to be pretty portable so a speaker capable of working in a box no bigger than around the 60l mark was needed. We also had a bias for something which would handle low frequencies without overloading too easily, this means looking at the excursion or Xmax and anything with an excursion below 4mm was out. Then we considered frequency response. We discussed the bass characteristics a little. The choice is really between an under damped speaker which characteristically gives a bass peak at around 100-120Hz of a few dB and rolls off quickly below that or a well damped speaker with a bigger magnet and more control which would give a smoother response and a respectable output down to 40Hz ish. We didn't consider an over damped speaker which roll off gently from above 100Hz but can give good tight bass and acceptable responses if you apply a little eq. Damping is measured in the Q of a speaker and overall Q or Qts needs to be about 0.4, anything above 0.5 is underdamped and likely to give a bass hump in a practical cab anything below 0.3 is likely to be very tight and lack bass output. We decided to go for a modern controlled bass response so we looked for speakers with a Q between 0.3 and 0.5. if we wanted to look for an 'old school' sound we would have looked for something with a Q somewhat higher 0.5-0.6. It's too easy to get a bit anal about bass response. It's the only bit you can really control as a cab designer and we are all bass players, but most of what we hear from a bass is actually mids and the higher frequencies are much more important in defining the 'sound' of a cab. We wanted a single speaker to cover the whole range for our first cab it would need to go up to at least 3500Hz and preferably higher. 12" speakers naturally cut off at about 1100Hz and response above this is down to the cone flexing so the sound comes mainly from the middle of the cone. A lot of speakers actually give a big increase in output at breakup so you get a peak in output from 1-3000Hz another contributor to the 'old school' sound. More about this later, probably. So the 'ideal' driver would specify Fs 40Hz Qts 0.3-0.5 Xmax >4mm 96dB/W frequency response 40-4000Hz +/- 6dB We modelled all of these and probably some more Beyma SM212, Celestion BL12-200x and BN300X, Faital PR300,Fane Soveriegn 12-300, Eminence Deltalite 2512, 3012HO, 3012LF, Beta12-II. more soon, I have to practice

The Monacor is designed to crossover at 5kHz so you couldn't use it with the 3012lf unless you wanted a hole in the response. I'm not a puritan about thin walled cabs by the way, I can see advantages with a rigid cab but the weight advantage isn't all it's cracked up to be. Alex Claber has stated that weight saving isn't his main reason for building cabs that way. What I'm sceptical about is that the difference between a well made lightly braced conventional cab and an equally well made thinner walled and heavily braced cab is that apparent in a gig situation. Since the weight saving is minimal and the complexity of build greatly increased I question how far it is worth it. A reasonably well braced 12mm cab might be worth thinking about too. One day I'l get round to building two cabs and do some A/B testing. Incidentally I have a 15" Deltalite in a 3/4" cab and the total weight is only 18kg, your cab will be smaller and lighter. Having modeled the 3012HO as part of our design process I think it would make a great cab on its own, though a single one in a West Country pub might well let the higher frequencies bypass you, two together would probably be OK. The sound is going to be very different from the Jacks even though you are using the same speakers, because of their design the Jacks have a 10dB difference in levels between the horn output at 300Hz and the reflex output at 100Hz and this colours the sound. the reflexes won't be as loud but the bass is going to be the same as the mids so the balance will sound deeper subjectively. One thing occurs to me, you really aren't too far away. We are looking for a 3012 to trial as part of our design, if you came up to Somerset for the day anytime it would be simple enough to clamp one of your speakers into a cab and for you to try it, if the sound is one you like the dicision is made. Ideally we'd like to run some tests at the time but this could be fairly flexible. I've got a couple of 50l cabs here.

If something looks too good to be true it usually is. Having said that the magnet is a decent size and the Chinese are banging out so many speakers for other people that it wouldn't be surprising if something half decent didn't find it's way here. there are three potential shortcomings, the first is that the speakers don't meet their specs. The power handling is probably right given modern glues and a 2.5" coil. Sensitivity is quite high for a cheapie but could be possible with a 50oz magnet. What you can't get is an average magnet high sensitivity and lots of deep bass. Have a look at the Eminence delta [url="http://www.eminence.com/pdf/Delta_12A.pdf"]http://www.eminence....f/Delta_12A.pdf[/url] with a similar magnet and coil and you'll see that the sensitivity is similar but the resonant frequency is much higher at 55Hz. To get this sensitivity at this frequency I suspect the excursion has been reduced and this speaker will overload or compress at relatively modest levels. If you are lucky it will sound OK at low levels but overload at noisy rehearsals depending upon what sort of music you play. Depends upon price really, you can get an Eminence beta12A II for about £50 which would probably be at least as good and has all the parameters available or you could pick up a used cab for under £100, but this might be a cheap way of dipping your toes into self building. It probably will beat your car sub hands down.

Hi Rich, there's a lot of questions there I'll try and deal with the woodworking ones first. If you do go for a 50-60l cab then it is quite small and you don't have much flexibility with shape. For example with a 30cm driver and a 10cm horn plus enough wood left to be strong enough to fix to you have a 50cm high cab and you want it 40cm wide. this means that for a 60l cab it will only be 30cm deep. This compromises the port as it can only really be 20cm long or it gets too close to the rear panel. If you want to tune deep then you need to restrict the port width or bend the port which introduces more problems. If you use a narrow port it doesn't need to be so long but can suffer wind noises at high levels. If you use a deeper cab you end up with a square front and an almost cubical cab where all the panels resonate at the same frequency. In practice you will come back to the 30x40x50 shape or thereabouts. Now the horn/tweeter. Firstly there are no decent piezo tweeters in reality, I've tried quite a range over the years and they do a job but with limited success. The old Motorola's which most of the currently available ones base their designs on were as good as anything the current Chinese mass produced ones are fairly poor and production in Europe and the States has ceased as far as I know. They'll colour in a bit of high end fizz and that's it really. 9mm ply really is very flimsy for making a high powered cabinet, The only way to stop it resonating and transmitting sound is to use extensive bracing. The bracing could easily end up weighing the same as the rest of the cabinet and adds a lot to the complexity of building the cab. I know it is very trendy in these pages to go for rigid, lightweight designs but it takes a lot of development to get it right, it may make sense for commercial builders with CNC routers and design budgets but don't knock the intrinsic properties of 3/4" ply. Secondly, why do you want a horn? Most of the stuff you want to hear from a bass ends at 4-5000Hz. A lot of horns don't cut in until this level, so are irrelevant to the sound, all they'll add in is string noise. If you want a real 'hi fi' accurate sound then you want something that covers the 1-5kHz range. Something like a PA horn. I sometimes use my PA speakers for bass and it does sound nice, The horns in these crossover at 1.6kHz. If I wanted a cleaner bass sound designed in I'd probably go for a 6" driver or smaller to provide the 1-5kHz range. If I was designing with a wide frequency horn or a mid range driver like this in mind I probably would go for a 'proper' LF driver but the 3012HO is a capable driver and as you have them I'd definitely try them first.

Hi, how soon do you intend building this? We are working on a design for a 50l cab which will match this driver, slightly derailed because I joined a new band and have 25 new songs to learn. This will be a free design for anyone to copy. The 3012HO is an excellent driver. http://basschat.co.uk/topic/227904-1x12-cab-design-diary/ You might find this interesting too http://basschat.co.uk/topic/200152-1x12-diy-cab-build/ If you go onto the eminence site you will see that the large cab has worse power handling than the more compact cab and they recommend using it with reduced power. This is a feature of all reflex designs not of this particular speaker. I really wouldn't go any bigger than about 70l nd we ended up going for 50l as a good compromise.

You don't need to worry about class D, just like the 'old' amps there are some that are oversold with 'car stereo watts' but there is no inherent reason why they shouldn't meet the specs or deliver every advantage they promise. Most of the weight saving is in the power supply which works the same way as the one in the computer you are reading this on, and they work. I'd always say there is no need to be louder than the drummer. if they need to mic up the drummer you can DI into the same PA the drums are going through. Money no object and I'd go for the AER Amp One, it's not stunningly light for its size but it is tiny and it delivers unbelievable sound. It looks like a practice amp but it'll more than match the beefiest percussionist. I'd say it's one you need to try if you can afford that much, if it is for you then you know you have the best solution on the market. If that style isn't for you then go for some of the options above and doubtless yet to come, Has anyone said Barefaced yet? The other option for someone who likes clean is to go for a powered stage monitor or PA speaker. The best ones can handle bass no problem and will be designed for a flat sound from the off. Just a thought.

I'm afraid that in oversimplifying some of the advice is a bit misleading. I'll summarise but you can get more detail here http://www.ultimate-guitar.com/columns/gear_maintenance/making_it_loud.html Most of the power from your amp is wasted as heat, only about 5% ends up as sound. The amount wasted varies from speaker to speaker. this is reflected in the efficiency of the speaker usually given as how loud it is for just one Watt or dB/W Some bass speakers give just 92dB/W and the best in terms of efficiency maybe 102dB. Every time you increase the power by 10 you get an extra 10dB and you need about 120dB to match a drummer. That's about 70W through the loudest speaker and 700W through the quietest. As said 300W through an average speaker will be enough. Size matters but only a bit. A big speaker will be louder than a small speaker if everything else is the same and doubling speakers up gives the same advantage in sound levels as having a big speaker, it's the cone area that counts. However lots of other things like how powerful the speaker magnet is will count too. It's possible for a 12" speaker to be loud enough on its own if it is capable of moving far enough and has a powerful magnet and many 15's will do it on their own too. If you are using a 100W+ amp in a rehearsal the usual reason for not hearing is that you are standing too close to your amp and it is pointing at your ankles not your ears. Tipping it back and pointing it at your ears will help a lot. Hope this helps

I'd like three black ones, the dipped small chamfer would be good, but any will do.

As someone who has spent a lot of time designing and listening to speakers over the years it is quite clear to me that you can detect very small differences between cabs in A/B testing even a tiny resonance at a very narrow frequency range can jump out at you in a listening test. You can easily hear differences in amps in A/B tests and even in speaker cables. Equally it is amazing how your brains can fool you into hearing something that isn't there. This is true of all our senses, I used to be a science teacher and you probably did a little experiment at school with hot, cold and warm water. Put one hand in the hot water for 60secs and the other in the cold, transfer them both to the warm and the 'hot' hand perceives it as cold and the cold hand perceives warmth. The same is true of sound put on a favourite track on your computer and turn the bass down just noticeably; obviously the song sounds bass light. Go on listening for a few minutes and turn the bass back to normal halfway through the song; it will sound bass heavy. Your brain has tone controls! My poor kids have been used more than once for blind testing of my projects because when you've spent hundreds of pounds and weeks of time developing something it is amazing how easily you believe good things of it. As bass players we all know the eq we set up in our homes often sounds terrible when playing with the band and that the sound in the rehearsal room is never like that at venues leading to much frantic knob twiddling. So, whether the minute differences we can detect are significant is a moot point. When shopping for a cab it is well worth spending time listening to speakers with your amp and your bass I would say, but don't expect the holy grail. Get something you like and then relax, the audience aren't really going to worry if you use Aguilar or Peavey unless you have a basschatter there.

Black would be ideal and stick on appeals. preferably as small as the one that started this off. The larger ones that are commonly available hang out beyond the pick guard making mounting them tricky.

If they are going to be around a couple of quid each I'll take 5.

It's good to have something with a battery, you end up with too many leads otherwise. http://www.youtube.com/watch?v=QVCJFE3bW9A this clips into your belt so you can move around whilst playing. I have one and I'd recommend it but the gain is just a touch on the low side, does the job though. My favourite is an old battery powered mixer for dubbing sound onto VHS tapes. You might find something similar if you are lucky.

I think what we are saying is that if they are up to the spec they are quoting then they would potentially be fairly good speakers depending upon how you use them of course. However they are unbelievably cheap and if something looks too good to be true it probably is.

Depends upon the price obviously but I'm happy to buy a few. I need two currently but I'd stock up if they were cheap enough. £8.50 is no problem if that is what it ends up as.

Balcro's car analogy is excellent. If you increase the weight of a car you need bigger springs. That's simple enough but if you just do this it is going to bounce around more, you need to change the shock absorbers to exactly match the increased weight and the stronger new springs to get the best out of your pimped vehicle. Mass, springiness and damping are all things which need to be calculated in speaker design and balanced out. You can't change just one thing you have to look at them together. To get deeper bass you need to tune lower and move the cone further. Just as in your bass thicker heavier strings or cones do lower the tuning, as does slackening off the tension. Just as Balcro says increasing the weight means less cone movement for the same power. Then to get the extra movement you have to have a longer voice coil. This also wastes power because most of the coil is out of the magnet at any given time and using power but not making the cone move. You can put in a bigger magnet to get the efficiency up again but this will also increase the damping and the cost so you have to get that right too. Price for price you trade bass extension for efficiency.

Thanks for this, I'd be very interested in a couple, or the file if you decide not to take this on.

[quote name='LukeFRC' timestamp='1391449422' post='2357292'] I'm going to say... can this thread be pinned please mods? [/quote] thanks. It might be better to create a new thread once the design is finalised with the design at the top, then we can drop further designs into that thread. We can link to this diary from there. Our hope is that enough people will build these and then tell us of anything we might do to improve future designs.

It probably uses some sort of Auxetophone http://www.douglas-self.com/MUSEUM/COMMS/auxetophone/auxetoph.htm#aux invented by Charles Parsons who invented the steam turbine.

Where did you get the thumb rest?

if you want to keep the character of the cab then don't replace the drivers. The character is both in the low end bloom using those speakers in that size of cab and in the various resonances in the high end. Replacing the speakers will change both though we could probably find something to match the low end. The new speakers might sound better or worse to you but will be different. The other thing is that there isn't the same choice of Neo drivers as there are ceramic ones. Because neo is an expensive material the neo drivers are designed to be high quality. Your 4x10 is designed on the basis that 4 low cost drivers can do the job as well as fewer more expensive ones. The cab itself is probably fairly heavy too so you wouldn't have a genuine lightweight cab. If you want lightweight there are plenty of cabs to audition to see if you can get the sound you want and it would probably cost no more to trade up than spending £3-400 on four neo drivers plus the value of your cab.

[quote name='ebenezer' timestamp='1390557034' post='2346686'] i too am looking forward to this!....just for info...I swapped the 12 inch driver in my aguilar gs 112 for a eminence 3012 ho kappalite expecting good results!!.... all i can say is,i was unhappy with the sound(yes i know the stock driver is 4.8 xmax and 95db......3012 6.2 xmax and 100.5 db)...i found it only a small amount louder than stock driver.....sound wise,it did not mesh well with tweeter and crossover...too aggressive in the mids and the bottom end not that good.....3012 now back in the box!....returned cab back to standard and sounds great!.....i think correct cab design plays a large part .it seems the lesser deltalite 2 might have been a better option(looking on talkbass) regards....mark [/quote] Hi Mark, the 3012HO is one we are modelling. It's a good example of what I was saying, Coincidentally the link http://www.eminence.com/pdf/Kappalite_3012HO.pdf is for that driver. If you look at the graph the sensitivity below 500Hz is only 98dB/W and when we modeled it it was slightly below this. The 100.5 they quote includes the mid peak, it's fair enough because they tell you how they test but also misleading. I wouldn't have expected much increase in sensitivity. To get the best out of it you would have had to have modified the crossover which was designed for the stock driver. Ideally we'd like to run tests on the 3012HO driver but we don't have one to hand. If yours is still back in its box then pm me.