Phil Starr

Hi John, I need to get off and do some work so I'll revisit this later, there's a lot of information here. It looks like your SM212 is still working, so that is good. If that is the case then Blue Aran are right, it isn't worth cutting it open. I'd thought it had stopped working. All the guff about winISD is disappointing. I've seen the same nonsense when Skidder blew his Eminence 3015 Kappalite a few years back. Win ISD just uses Small's equations to describe the cone movements, they can't seriously be arguing that the science is all wrong. The stuff about not being suitable for bass but for PA is also nonsense. What do they think goes through a PA? Clearly they are denying the possibility of using a bass through PA or the existence of bass in recorded music! They are also wrong about the SM212, it is a general purpose driver, Beyma also make the SM112 which is the dedicated PA bass driver. In their English language material they do not talk much about applications and neither critically do Blue Aran. In any case the physics don't lie. They do have a case however about using a bass without a HPF. It's something we have mentioned and true of most commercial units too, in fact it's an issue with all ported cabs and not much discussed. At 40Hz and 300W your cab will not exceed 13.5 mm excursion. At 30Hz and 300/w it will, the speaker isn't indestructible. In any case you shouldn't use the speaker beyond xmax for extended periods and the 13.5mm figure really is an absolute limit. The 25% figure comes from TKS I think and is a good rule of thumb, it doesn't mean you personally use your bass in exactly that way. I'm concerned about Blue Aran's attitude, which may be down to one over zealous employee of course. I think they are trying to browbeat you, and not engaging helpfully, and this is the second time I have seen this. You may well have been using the speaker outside of the parameters of safe operation, we may never know exactly. They may have good grounds for saying that it isn't their responsibility but some of their assertions are untrue and their tone is certainly aggressive and unhelpful. Last time they came on here and did engage a little. It would be useful to know if they are a company with the highest standards we can recommend. I need to go back and look at all of your details. I feel a little responsible for this and if necessary I might need to tweak the design or add some more advice to stop it happening to anyone else.

It's hard to say without more information. It squeals when turned up. Does it do this when there is no signal which would indicate damage to the amp inside, or when you are playing music(not bass) through it. Does it play music when you have it turned down but distorts when you turn up? That would indicate the amp is probably working OK but something mechanical has gone wrong with the speaker.

I share your position at the bottom of a big scary mountain that needs climbing, this is a thread I'm going to follow. Just a little personal insight which is going to make the mountain twice as high, it isn't all about notes, have a look at this and see what you think. I'll never look down my nose at Britney and Pitbull again https://www.youtube.com/watch?v=CtZ74JdxCt0

I was aware of that as I was writing. Then I thought that actually reading is the ultimate skill that makes it possible to unlock a lot of 'theory'. I don't think you can really separate a good grasp of theory from reading I gather little bits of theory when I can, it all comes in useful but I still feel like a blind man. For example I've only recently started looking at the theory behind rhythm. As a bass player the little dotted squiggles, the timing of the notes and the bar lines should have been what I looked at, not being so dazzled by the notes alone. I've been looking at the letters not the words. How the hell do I get better without a proper grasp of what note length really is, and how do I do that efficiently without being able to read and write? As a drummer you must be smiling now.

[size=4][color=#545454][font=arial, sans-serif]"Any technology, no matter how primitive, is [/font][/color][color=#6A6A6A][font=arial, sans-serif][b]magic[/b][/font][/color][color=#545454][font=arial, sans-serif] to those who [/font][/color][color=#6A6A6A][font=arial, sans-serif][b]don't understand[/b][/font][/color][color=#545454][font=arial, sans-serif] it" Arthur C Clarke[/font][/color] [color=#545454][font=arial, sans-serif]Our old keyboard player, classically trained, could listen to any song pretty much that we were learning just once and could then play it both hands, so effectively bassline, melody and chords all learned in real time. That seemed magic to me, and if I'm honest still does. I kind of know what she was doing, most pop songs use four chords and the melody will come from the scale tones etc but I can't do that. She has music theory and I don't.[/font][/color] [color=#545454][font=arial, sans-serif]Without music theory we are like a story teller who cannot read. Reading means we can talk to each other across space and time, we can talk to everyone who has ever written anything in a language we understand. Writing means we can swap ideas with other people and share ideas. Why would anyone think that exposure to the whole of English Literature would stifle their creativity?[/font][/color] [color=#545454][font=arial, sans-serif]I still painfully learn every song by rote. I don't reject theory I hunger for it, like the OP I wish I knew where to start. Personally I'm ashamed of not being able to read music. I know even a little more knowledge would unlock the musical place I'm confined to. I feel as those poor kids who struggle to learn to read must feel daily every time I get stuck with anything unusual in a new song.[/font][/color][/size]

Critical question really, would you ever build yourself a cab from scratch? If you would then the 3012HO is still one of the best drivers out there and, were it not for the cost, the driver I might have gone for in the Basschat 12" design. Build one of our cabs and swap the 3012 into that if you don't like what it does in your GK and you'll have a lovely cab.

Hi Stevie, depends what you see as 'no bottom end'. It's Q=0.8 which is almost maximally flat from this driver. The response rolls off from 200Hz but is only a couple of db down at 100Hz and -10dB at 70Hz.. Porting the same volume you'll get a couple more dB output from 100Hz down and roll off from 150Hz. The main difference is that the excursion below 40Hz is pretty much uncontrolled with a ported cab, making any bass boost a bit problematic. Giving modest bass boost (say 3dB) to the sealed cab would be an option which wouldn't threaten damage to the speaker but would restore bass to the sorts of levels a ported cab would give. The OP has an 18l cab or thereabouts. You aren't going to get a huge bass output from a cab that size with a 12" speaker His original driver probably gave him the usual bass hump above 100Hz with little deep bass anyway. I think the 3012 would give him a clean sounding bass, although definitely a bit bass light. My advice was to return it to original though. It's a lot of money if you find out you don't like that sort of a tone, and a bit of a waste of a good driver to put it into such a restricted cab. I took the question to be 'would it work?'. The only reason I looked at the 3012 was because a tiny box requires a decent sized magnet to achieve good levels of damping it was the just the first speaker I thought of that I know I have stored parameters for. There you are Owen, we disagree slightly, Stevie is right to challenge me probably. I've only had a quick look so don't rush out and spend £200 yet.

[quote name='DrBike' timestamp='1480667862' post='3186182'] That made me guffaw! Kiat - It's probably not on your list but I would definitely not look at Weston-uper-mare or it's surroundings. I moved here just over a year ago and there's practically nothing going on at all. You could try around Reading/Maidenhead/Windsor as there's quite a lot of live stuff going om (certainly compared to here). [/quote] Made me smile too. How do you find stuff in and around Reading though? I moved down to the West Country from Reading 20 years ago. I go back fairly regularly to visit friends and usually look out for live music or open mics and can't find anything like as much as down here. Berks seems to be cursed with dozens of websites that aren't kept up to date. Down here a quick search on Lemonrock turns up dozens of gigs every week without fail.

Depends upon what you mean by music scene, are you talking as a performer, as audience or just where there are plenty of people up for a jam. Are you talking covers or live original music? I'd say lot's of original live music might be tricky outside of the big cities as that's where the younger populations tend to be. You didn't mention Bristol which is pretty good for it's music scene but is a city of course. Exeter and Torbay has a fairly lively scene of covers bands and there's a fair community of musicians to tap into, there's also a lot of open mic stuff going on and an opening for the solo performer and duo's in some of the country pubs and smaller coastal venues. It's not so easy for originals bands or young musicians though. It's all relative though, Bridport has a good artistic community all round for its size for example, but it is a small place and you''ll soon have located every musician in town.

Hmmm, well I couldn't do it.

I do know J and Lizzie, they live just down the road next door to one of our best friends and the singer in my first band, lovely people, small world. Do you live down this way? The 3012HO models well in that it has a flat response in your cab down to the cut off frequency and then the slow roll off sealed cabs usually exhibit, ideal for a bit of tweaking on the tone controls. Your cab could have been built for it in fact. The 3012 won't exceed it's excursion limits until you put out 250W at any frequency, so no farting out I would think at all. It also has quite a nice top end and sounds good with bass. [url="http://www.bluearan.co.uk/index.php?id=EMIKLIT3012HO&browsemode=manufacturer"]http://www.bluearan....de=manufacturer[/url]

I've had a quick look at how the Eminence Beta and the 3012HO model in that cab. As said it is very small for a 12" cab, so small that I doubt the decision to make it that size was based solely on sound. The Beta has a big hump in frequency response at 120Hz and rolls off after that. I suspect what you had does the same. there wouldn't be deep bass but plenty of the bass you do have with the Beta. The 3012 models really well, do you want to spend £200 on hot-rodding? I'd go for the original at that price.

[quote name='JapanAxe' timestamp='1480540048' post='3185301'] Rehearse your stage moves. Seriously. If you practise playing while staying still, that's what you'll do on stage. Try your moves at home in front of a mirror, and do them at rehearsal. [/quote] [quote name='FuNkShUi' timestamp='1480579155' post='3185489'] Just do what feels natural. If you have to think or plan what you're going to do, it's going to look like you've had to do just that. That's rarely ever a good luck. Don't think too much about it, move with the music as much or as little as is natural to you. [/quote] Both of the above. It's worth thinking it through and certainly moving whist doing bass practice is a good idea, you'll develop moves which come naturally and look OK if you do it in front of a mirror. Having a few moves or poses of your own, or borrowed from your favourite performers, helps limit the embarrassment factor when you first go up on stage. However unless you and your band are going for a full choreography of the set then I think it has to come naturally or it can look a little odd and uncomfortable. FWIW I read of a study, in New Scientist, of dancing as a display, apparently small movements of the legs when independent of the movements of the upper body are deemed most attractive. Since your hands are going to be involved in playing bass that must mean don't overdo the dancing. I don't think dancing is always the answer though. The audience want something to watch as well as listen to, and to see you enjoying what you do. If you aren't a natural mover then it's amazing what a bit of smiling and looking at the audience does. I think the audience also like it when there is plenty of interaction within the band.

https://youtu.be/o6rBK0BqL2w Nice tune as well.

I've no information about any of the gear you are using, so you'll have to look it up for chapter and verse. This is a kind of primer/rule of thumb about pre amps. I hope it's enough to help you get things sorted. It's all about gain. A bass gives out around 1/1000 of a volt. A lot of pre amp circuitry operates at around 1/10th of a volt (a gain of 100 in other words) most power amp stages take about a volt so there will be another gain stage of about 10 somewhere. Obviously these are approximate figures and different manufacturers have used other options. Obviously you don't want to go into distortion and the Vpp (volts peak to peak) is just an expression of how high that stage can go before distorting, it doesn't say anything about gain. Some fx are designed to go into the guitar input and give out a few mV, most go into the fx loop at around 100mV, 1/10th of a volt. Others might be capable of driving a power amp direct. So, my guess is that you need something that gives you a little extra gain of about x10. For experimentation purposes a PA mixer will give you all the gain you need, beg, steal or borrow one of those, once you have the sound you wnat you can then look for a cheap pre=amp stage that will give you the little bit of extra gain you need. There will be fx capable of driving a power amp directly though, but you need clean gain not something that is designed to distort at higher levels.

Well sometimes it's good to try to help, that site with the circuit diagrams on is great, thanks. Unfortunately there's not much I can offer. The volume and tone is all handled electronically so you'd need to break in to the circuit after the master volume. On the plus side the noise is unlikely to be coming from the pots as they aren't directly handling the signal. My guess for the noise is that it is coming from the DSP as it is only happening when you play. Is it affected by which amp sims you use or the opto comp?

You are going back to a time when 25W was a high power speaker and 50W was pretty exotic. Speaker coils were wound onto paper and stuck down with very simple adhesives. At any higher power the paper singes and the glue melted letting the coil distort and rub against the magnet. A 100W amp cost several weeks wages. I remember Goodmans bringing out what was the first affordable 50W 15" speaker in this country. If you wanted a 100W speaker until then a 4xsomething was the only way. It also raised efficiency to the level where 100W was enough to fill a large auditorium. You are also going back to a time when speaker theory was pretty much unknown. Thiele re-published the theory we all use in 1971 and it took a while after that to be widely adopted by music speaker designers. Partly that's why there are so many bonkers designs from back then, no real theory. Basically the reason we don't use 4x15's is better glue

Yes, we should probably have started another thread though I am sure interested other people are looking in. I'd always recommend measuring the inside diameter of a pipe anyway. Then winISD will recalculate the length for you. You could look at three 75mm pipes as well they'd have a similar area to four of our smaller pipes. the other source of ports is the cardboard tubes that come inside rolls of carpet, carpet warehouses will let you have them for free as they are just waste for them. You could also try re-tuning the cab to 40Hz to see how that affects the excursion. Don't forget to check the maximum power chart too as you will lose out there at frequencies a little above the tuning frequency. I don't like octavers on the bottom notes, in most of the rooms I play they either can't be heard or excite room resonances and make the band sound bad. One way round this is to use a HPF filter like a Thumpinator that will take out the lowest frequencies but leave the octaver to thicken up the notes when you are playing higher up the neck.

The air velocity isn't the problem so much as the excursion which is causing it! Air velocity will lead to some noises from your ports but the excursion will destroy your speaker. The reality is that your speaker won't go down to 30Hz at high power and neither will most commercial speakers. If you check out most of the designs on the Eminence website you'll see they usually recommend using a high pass filter to stop subsonics getting to pretty much any compact design using a ported cab. In normal use there isn't usually too much signal coming out of the pups at these frequencies even with a 5'er but when cabs fail it is often down to someone pushing these frequencies through in an attempt to get 'more bass' 63mm tubing is ordinary gutter downpipe http://www.screwfix.com/p/floplast-downpipe-68mm-x-2-5m-black/25256 Their 68 is the outside diameter.

Change the cable or at least the plug. The vibrations may be moving the plug around but it is the steady force of gravity that is pulling everything in one direction, so supporting the weight by tying the cable onto something is a good temporary fix. The jack socket may be damaged but there is a fair bit of spring on most sockets so there's a good chance it will be undamaged, but stop using the over sized jack. If you continue to have problems then you have to get a tech to change the socket for you. You can't really gig if you know your kit is unreliable. It shouldn't be much more than the cost of opening the amp up.

I don't see why a combo is difficult to comprehend, even though it isn't my normal choice the idea of plug and play with light weight and the sound of your choice is appealing, why not? I can't see Alex doing this soon though. I used to manufacture custom speakers back in the 70's. One of the retailers I supplied persuaded me to produce amps. The multiplication of both suppliers and processes killed what had been a growing business. I was completely under capitalized and that along with the increased workload finished me off. If you are small it makes much more sense to stick with what you are good at. Maybe if you are big too.

The reason it pounds better is the extra speaker, for all sorts of reasons. Cone area, speaker placement and sound reflections off the room. It almost certainly isn't anything to do with the amp as you now know.

[quote name='hrnn1234' timestamp='1480069131' post='3181403'] Well, evidently there's a difference between monkeys like me clicking buttons and people who knows their stuff! The bump you predicted is quite visible (colors are the same as in the previous graphic I posted). Still it seems the speaker could perform quite OK. I was thinking in getting the Beyma from Poland, as it would be a bit cheaper but, I could maybe attempt this build. Even if it fails horribly it would be a cheap lesson. And goes without saying, thanks all of you for sharing so much knowledge! [/quote] Ha ha, when I started it was all algebra and slide rules, every calculation took so long you tried not to make mistakes and were very conservative in what you did. Chienmortbb just recently described speaker design as being like squeezing a balloon, every time you tweak the design somewhere something pops out elsewhere. I think given the time involved and the expense of the cab I'd pay the extra for the Beyma, you can see what it gives you on your graphs, it is also better finished than the Thomann so you'd hope it my be a little longer lasting. [quote name='Gottastopbuyinggear' timestamp='1480080755' post='3181510'] Just a quick addition to say I'm still happy with the version I built from the information/specs in this thread, and using the new version of the Beyma driver. In fact I'm twice as happy now as I was last time I posted, as I've finally finished the second cab, and used it at a practice the other day. I was taken aback by the difference the second cab makes. I wasn't really sure what to expect, and was anticipating perhaps a bit more volume. What I actually got was oodles more bass than I expected - I usually run my Ampeg PF500 with all the EQ at 12:00, but by the end of the evening I'd backed the bass off to about 09:00. I can safely say that there is absolutely nothing lacking in bottom end for a four string player, and I think I understand some of the comments from others who've played your prototypes, Phil, that the flat response might sound odd to people who are used to a bit of a mid hump from many commercial cabinets. [/quote] Yes I had the same experience, Two of them create a lovely creamy bass but I ended up rolling it back the same way so as not to excite room resonances and swamp the rest of the band. I glad you were happy enough to build a second cab.

That's as predicted 80l is a big box for a single 12, put it into a 50l box and you should see the hump appear. I'm assuming you put Le into WinISD which is why you get the roll off at higher frequencies. The software doesn't 'know' the frequency response of the speakers so it is just calculating a theoretical frequency response for the whole system. It's only really very accurate at the bottom end.

No, it looks good value, the W variant has a bigger magnet and a roll surround and it's resonant frequency is consequently lower. I wouldn't use it without a horn and crossover though, it cuts off early and has some nasty breakup resonances. I couldn't find any t/s parameters though. The A would be better for bass, the frequency response looks good and Xmax is excellent for a cheap speaker. The drawback is the smaller magnet which means damping (Qts) is quite high. I suspect in a practically sized cab it would have a significant hump in bass output around 100Hz. as many cheaper commercial bass speakers do. If you struggle to model the cab yourself let me know and I'll have a look for you