Phil Starr

@Pirellithecat if you think this is a thread derail let us know and we'll take this elsewhere. If you are interested I hope the nerdiness is interesting. @agedhorse is right and it is something @stevie and I have talked about before. The 'ideal' speaker cone is a piston moving backwards and forwards without bending pushing the air exactly tracing the waveform of the current flowing in the voice coil. Of course in life nothing is ideal. Cones are heavy fixed on the outside to a springy suspension and are mainly made of papers so they are a bit bendy. As the frequency rises the coil will do it's best to keep up but the outside of the cone lags behind a bit eventually the cone can be seen to be flexing so that some parts are going forwards at the same time as other parts are going backwards. It's often said that the centre of the cone radiates all the treble and the whole cone the bass, but the truth is that it is messier than that. The bits travelling in different directions cancel each other and the bits going in the same direction reinforce each other and the frequency response suffers. Its a distortion of the original sound. I tried to find a laser interferometry picture of this on YT but all I found was a computer simulation. Loudspeaker cone breakup (in a typical loudspeaker) 3 - YouTube At this point there are design problems/opportunities and both have been chased. One approach is to say 'I'll make a stiffer cone' it is distortion and a proper piston is what I want'. The problem then is beaming at the frequency where the wavelength corresponds to the diameter of the cone (ish, it doesn't all happen at once) Another problem is that stiffness usually raises the mass of the cone significantly and other things are lost. One significant thing is that when a stiff cone breaks up it usually sounds horrible. The other approach is to say OK I know this is distortion but I can live with a little and manage it. I'll try and control the flexing so that the middle of the cone does the treble so I reduce beaming and get a flatter response up to higher frequencies. 'Heck, if I get it right I won't need a crossover'+. In a sense the original Barefaced Compact with the 15" driver took that approach, you can have a 15 with enough top end to sound good. Peavey had a Black Widow 15 with an aluminium dome which sounded good and in years long past I used PA speakers with a whizzer cone which I got away with. There was endless experimentation with this in 70's hi-fi. At the time the goal was to make a 2-way speaker with an 8" bass unit and a 1" tweeter and with the technology of the time there was a gap between the point at which an 8 starts beaming and the point where you could reasonably ask a 1" dome to take over. That was a special problem because that point was right in the middle of our hearing range where even small distortions are noticeable. One solution of course is to have a 3way design with a mid driver but that creates further problems with the crossover. This is of very little help to someone choosing a bass cab however, cabs will differ in their radial response in very complex ways. there is plenty of physics to guide designers but no perfect solution and the real picture once you take a cab into real rooms with room reflections bouncing sound all over the place mean that a cab that works well in one room can be a nightmare in another space. Little of this information is available to anyone choosing a cab anyway, but I hope it is reassuring to anyone stuck in a venue struggling to get the on-stage sound right

Give it a go, buried in the text here is all the help you will need and @stevie will sell you the components for the crossover at more or less cost. There's a cutting list here too so you can get the panels cut to size before you start and all you need to assemble the box is glue and a screwdriver. The rest can be ordered on-line from two suppliers. If you give it a go I'll start a new thread and talk you through the process and hopefully others will see how easy it is.

we've done this before I think, there are a few considerations for panels, toughness and weight for practical reasons rather than sound. Then there are sonic properties; mass, Young's modulus (springiness) and self damping. Ply is usually used as it is light weight, tough and finishes easily. MDF is the densest material with good self damping so has low resonance, it also has the fatal flaw of swelling if it ever gets wet. Chipboard (particle board in the US) is somewhere in between but more difficult to finish but comes in a wide variety of grades, it is usually cheaper too. Sonically MDF is great for speaker cabs but only usually used for hi-fi where cabs are smaller and aren't moved around. Chipboard is good and you can get special boards where the finest particles are on the outside and that makes finishing easy. A lot of old 70's stuff is made of Chip. at one point the 'wrap' was made of ply and the baffles were chip often of greater thickness. Ply is probably the least appropriate material for speakers but really practical for portable gear. If you want to build this cab you can use any material you want.

Actually I think you should pause here. It's interesting to know a bit about dispersion but it is only one of many things when choosing cabs. Unless you are going for FRFR then surely the most important is how the cab sounds. Dispersion was a problem in the rehearsal room but might not have been with the Vanderkleys (vertically stacked of course). Are you unhappy with the sound of the Vanderkleys or just fancy a change? Nothing wrong with looking at all the options or just being bored and wanting to move on but dispersion is a thing, but just not the only thing.

Without trying all the cloths from all the suppliers I can't be certain John. I found out by accident when I warmed a piece of cloth to soften and stretch it and it contracted instead! I now have a piece just too small to fit since then I've seen a couple of YouTube video's confirming this all on fender style cloths. The Chinese suppliers list the cloths as 'American Style' and the patterns match the Allparts patterns exactly so I assume they are manufactured in China. My guitarist wanted a cab with the Marshall Salt and Pepper cloth and that is a much stiffer fabric which chars but doesn't contract when heated. Fortunately I tested an off-cut before fitting that time. The Marshall fabric is listed separately by the Chinese as 'British Style' so i'm assuming it's a different weave until I know otherwise. I'm considering ordering a roll of fabric from them as a trial once I've had a go with a few samples. It's really sad that none of the UK mills seem to be supplying any good quality fabric. In the years when I built speakers for a living back in the 70's I had a wide choice of suppliers. I can only find a wide choice in the US and China now or pay the high prices that Allparts charge

I've recently fitted this to a guitar cab Amp grill cloth - Marshall style - Bluesbreaker Re-issue - 33" wide (p – Allparts UK it's very substantial, Actually quite difficult to stretch over the frame but affords great protection. There's a Chinese supplier that is a lot cheaper and I found mine from another UK supplier a bit cheaper but they have sold out. I've also recently tried some of the 'American Style' grille cloths which are great, they shrink when heated which makes them so much easier to fit. Alternatively try Speaker Grills for metal grills

I'm not the one to comment on this really. I'm a relatively modest bassist, a latecomer to playing and a weekend warrior so I pretty much avoid questions of taste and stick to technical stuff where i have a bit more knowledge. You're probably right though, that cab was quite bright but it had a pronounced mid scoop which I didn't like but which i know a lot of bassists prefer. I tend to use a flatter or even mid forward response and roll off the bass in most venues and that seems to work OK when playing live. I've probably spent more time mixing than playing bass and I eq so that the bass keeps away from the guitars and kick drum and sits in the pocket between them. that doesn't work with all types of music though.

it's really interesting isn't it to ask how much output at 40hz is useful. I've a little 6" cab at home specifically built to test this. It's pretty nearly flat down to 80Hz, the second harmonic of bottom E, and then the frequency response falls off the bottom of a cliff. Surprisingly perhaps it still sounds like a bass guitar with almost nothing in the bottom octave where the fundamental lives. A fair number of recording engineers filter everything including bass at 50Hz and I've tried music both with and without a 50Hz filter . Most of the time even directly between them it's difficult to hear a difference, if you heard the recording on it's own I don't think many people would spot which was which. Finally at a SouthWest Bass Bash we did some blind testing of a group of 12" speakers. About 40% of people said they preferred a Mark Bass cheapy over a Fearless/Barefaced/BassChat line up because of the extra bass. The thing being that it was the speaker with the least bass below 80Hz but it had a big bloom in the 80-160Hz region and an imbalance between the bass and mids which those bass players all heard as 'bass' and preferred. They weren't wrong of course, any audience would have heard it in a similar way. I'm finding the psychology of sound perception as interesting as the well worked science of cabinet design and it is probably as relevant to practical cab designs as the science is to achieving the design goals.

More of the above really. Speakers beam depending upon how far apart the moving parts that make the sound are, it is related to wavelength and you can't escape the physics you have to work with it. There are two ways practically you can have enough bass output and still have decent dispersal, split the frequencies or have a tall narrow column of speakers. Funnily enough you don't have to worry about the bass itself because that is pretty much omnidirectional but the mids are what you need to really hear what you are playing. So anything with a horn is going to improve things, your horn is typically going to have a 1" exit point for the horn driver and the horn itself can be shaped by the designer to control dispersion. If you delve into the detail you'll see horns specified for dispersal and a typical horn might say something like 90x60 which means it 'beams' 90deg wide and 60 high. You'll only see this if you self build though. As to the 'column' speaker though the smaller the speaker the wider the dispersal of higher frequencies and the smallest bass speakers from most manufacturers are 10's and that is still quite large. The width of the speaker is the distance between the extremes of the speakers though so a 2x10 on its side is as far as radiation is concerned 20" plus the gap between the speakers and a single 15 is better than a 2x10 on it's side. You can buy 8's or even 5's and a 4x8 vertical column is probably as good as you can get to have full output bass from a cab without a crossover. The column though only works in one plane, a column creates a wide flat radiation pattern for the midrange and upper frequencies. So in a practical sense there are a few things to do. Get two speakers and stack them vertically to get the wide flat pattern. This will also raise the top speaker to head height which helps a lot, no sense in blasting the back of your knees with precious mids when your ears are fixed to your head! Alternatively look for a kickback speaker so that can be pointed at you. Better still though look for something with a horn and preferably sit that on top of another cab to get that up high too. If you really don't like a horn sound then turning the horn off in the bottom cab is an option that can give the audience the sound you like but lets you hear your own sound better. The best solution might be in-ears though, but that is another story.....

Hi Al, do you want me to comment here? It seems a nice thread and even though I think we would be back quicker if we organised properly as a country as well as having saved maybe 100000 lives I do like reading about the gigs and the gradual return to normal Maybe we should do this on another thread?.

That all sounds perfectly sensible. The only minor issue is that you will be changing the internal volume slightly and that could throw the tuning out a tiny bit, but that is all fixable if it proves to be a problem.

The big advantage of building your own is that it opens up choices, a difference yes, a significant difference? Well probably not. John's right, the reason I've used this method is that it is the easiest by a distance and probably the strongest. It's also really quick. The only tool you need to build the basic box is a screwdriver, any other method needs extensive clamping whilst the glue sets. Technically the joint is a reinforced butt joint and the main aim is to increase the glued area, all the screws do is hold the battens in place whist the glue dries. There is also a sonic advantage; the butts transfer energy across adjacent panels and help a little with panel damping. If you remove the battens you should probably look at other methods of transferring energy between panels but internal braces should do that and almost always using less material. If you are a competent woodworker though there are loads of other methods you can use. Dovetail and finger joints will also double the glued area and hold panels in place with minimal clamping needed, dowels certainly help with lining everything up and a well made simple butt jointed cab is still a fairly strong structure. My method is for those without a lot of woodworking tools and less confident of their skills. the important thing is that you are comfortable with whatever you choose.

OK, is this something you want to crack on with or do you want to wait until @fleabaghas his first 1x10 built? If you do want to start straight away I'm not likely to build mine for a while but so long as you are happy to share the process with other people I'm happy to design something for you that others could copy too. If it is just a simple 2x10 then it's not a difficult thing to design and we could customise it to your needs if you wanted. You can tell I've got no gigs can't you, too much time on my hands in the evenings

Sounds interesting, It's amazing how little real bass you can get away with sometimes.

Ha ha I shouldn't have gone to the gym, now it's got complicated, but everything people are saying is about right. mains in this country (UK) and across the EU is 230V nominally, but that varies depending upon where you are along the power line. Our house averages at 242V. So theoretically 230w is 1A but the general calculation that 250W is 1A is good enough. There's two considerations here; you don't want to trip the fuse and you don't want to set the internal wiring alight! Most household fuses are slow blow to avoid them going every time we turn something on, most stuff in a house takes less power as it warms up. Steve browning has asked the crucial question, what is my amp using when it is on 3? That's amazingly tricky to work out. If you are damping your strings properly there's a lot of time you aren't putting out any sound, all your notes start loud and then decay etc. The 300W or whatever are simply the top limit you hope to never get near. Then again the amp isn't 100% efficient. Switch mode power supplies are better than transformers, transistors better than valves. Modern electrical appliances now have to have an estimate of average power, have a look on the back of your amp if it is recent. My 500W Peavey says 160Wh electrical consumption so that's an average of 160/230 of an amp when it is run quite hard, about 1/3 of the 500W max output. The next issue is the inflated watts that are advertised, for calculating currents you need good old RMS watts (that's where the square root of two comes in, RMS=root mean square) Most single speakers only handle 300W as a rule of thumb so that 1000W Yamaha PA speaker is actually only 500W at best and needs less than 200W of electricity an hour. SO add up all the watts of all your amps/lights and so on and allow 4amps for every 1000W. If you are using solid state amps class D or otherwise and LED lighting then I really doubt most pub bands will be using more than 3000W. You don't need a lot of headroom, as in my Peavey I doubt you'll be running at more than 30% for anything longer than a few microseconds. You only need a second socket if you go over 3000W and that gives you a big safety margin. If i have to go for a second socket I look for a twin socket. In a double socket the two sockets are connected by big copper/brass strips so they are properly earthed to each other by design. I don't trust electricians I haven't met as I've worked on building sites. Most are safety conscious but people make mistakes. If I have to split then I run one circuit for the amps and a separate one for lights and make sure no-one can touch the lights. Your mics are earthed through the PA so you need that plugged into the same earth as the back line. The final thing is to make sure your mains leads are in good condition. There's no point in trusting a single socket if anything you bring in has a broken earth. That's where a circuit tester will help, and use the RCD on your single socket if you think there isn't one elsewhere, though most venues will have regular checks for insurance purposes.

I always plug everything into a single socket. I've had problems in the past with floating point earths. This is where different circuits in a building are poorly earthed or sometimes not at all. That leads to the earth connections of some of the wall sockets being at a different voltage to other sockets. Since the outer metal parts of our gear are often/usually connected to earth that touching the metal parts of your bass and another metal object like a mic can lead to quite an unpleasant shock. It's relatively common in old buildings but I've even had the problem in new buildings. If your own gear is all sound and plugged into a single socket you know everything is at the same earth potential. With modern gear you are really unlikely to be drawing 13 amps (3000W) so overheating shouldn't be a problem so long as your cable reels are unwound.

For those looking for a really tiny speaker for home practice with lots of detail and a satisfying sound without neighbour annoying deep bass I built a 6" speaker. The details are here, it was just a bit of fun but if you live in a tiny flat it might just be interesting

This is probably the outside dimensions? What you need are the internal ones, I've never seen an Elf in the flesh (!) so I've no idea what those are but my best guess was the internal volume is nearer 27l allowing for the wall thickness and the baffle being set back. I normally just take a notional figure for the intrusions into the cab so I've been working on a nominal 25l as the volume of the Elf. I don't see a lot of point in designing a 40l cab for what you want. The 10CMV is fairly tolerant of cab sizes and you might as well stick to the BC Easybuild cab which is just over 35l. You need to decide the driver you want to use and how important size is to you. When you have a better idea I'll do a more detailed design. We ought to start a new thread though.

Hi John, this is the Fane (purple) in a 25l cab against the Beyma in the same cab tuned slightly differently to get the flattest response. The Fane actually 'needs' a smaller cab to get the flattest response, around 20l. -3dB is 10hz lower and there is an extra 3dB at 50Hz so noticeable extra deep bass. There's a ripple I couldn't design out but no real peak. Which would sound best would be a matter of taste I think.

OK as a starting point here are the responses of the 10" Beyma CMV in a variety of cabs. 50l which is WinISD's first suggestion (green) the 12" Easybuild/110T cab (red) and the 25l cab you were hoping for (blue). You can see the 50l cab gives you a lot more bass and the flattest response the 35l cab gives -5dB @ 50Hz and the 25l cab significantly less bass and an audible extra warmth at 100-120Hz. If you went for this speaker in the smaller cab it is flat down to 80Hz which is important as it is the second harmonic that we mainly hear as bass. It's going to sound like a bass speaker but bass will sound light and fast if that makes sense. The Beyma also has a slight peak in the upper midrange so it should cut through quite nicely with a bit of 'old school' sound about it. The Eminence Legend would show a similar pattern of responses but it has a more significant upper mid boost which would give a genuine old school feel about the response. Essentially if you want extended bass in a small package you need a more powerful magnet system than these speakers have. hence the iron law about you can have small, cheap and loud but not all at the same time. However if you you don't mind compromising on the deep bass I think any of these cabs would 'work' especially for home practice where deep bass isn't really helpful. The SM110 was a better driver but as they don't make them....

here's the drawings of the 10.

The cab is essentially the same for both projects, there's a difference in the porting because I prefer the build simplicity of using downpipe which is so easy to get hold of. Stevie who designed the lockdown 10T prefers a bigger diameter (ooh err) to reduce port noise. The dimensions are deliberately small to restrict the bass out put for the 12 but Stevie always said the cab would suit a 10. The tuning of the 12 is also slightly higher. As to writing it all up properly, I agree but I already spend too long on bass chat and not enough time playing bass I'll get on to it but it might take a while.

Since it is you I'll have a look at the Beyma 10CMV. I was toying with the idea of designing a 2x10 as a next project and if it needs to be low cost then those Beymas look to fit the bill. It's little extra effort for me to give you a set of designs for a 1x10 and a 2x10 so you can then make your own choice as to what you want to build. The only thing you need to do is to put up plenty of pictures of the build and then to tell us what you think of the sound at the end. I know you'd do that anyway and it will be good to share another design without having to fill my house with yet more speakers and sawdust. I'll get back to you tomorrow hopefully.

Phase is a moderately complex idea, so for anyone not familiar. Speakers (anything making a noise actually) move backwards and forwards travelling fastest in the central position then slowing at the ends of travel before turning round and going back the the other extreme where they slow and return. That creates pressure waves in the air that radiate out into the room. At the back of the speaker the pressure wave is reversed and the air is pushed in the opposite direction. It is 180 degrees out and if you let it mix with the air at the front you get cancellation and no sound. Many other things can delay the sound including distance and the air can be any amount 'out of phase' or not at all so you can get anything from double the sound from an in-phase sound to complete cancellation (which is what sound cancelling headphones do) Any time delay in the sound leads to phase cancellation but the 'phase' is dependent upon the frequency of the sound. Higher frequencies go through more phase change than low frequency ones in the same time. In a ported speaker the mass of air in the port is bouncing on the air in the cab; it is resonating if it is in action and like a bass string it only does this at one frequency (sort of) The trick of the designer is to set this up so it does this just as the speaker is dropping off in its frequency response. Once the port starts vibrating it pushes back at the air inside and if you get it right the cone of the speaker stops moving and all the sound output is coming from the port. So at the tuning frequency you aren't going to get cancellation/phase issues. The speaker isn't making much sound at that frequency. Above that frequency the port output falls really rapidly so phase cancellation ceases to be an issue. Finally all this is happening at the very lowest frequencies the cab can realistically reproduce so the phase shift isn't great and frankly our ability to discriminate sound at those frequencies is really poor. Any issues would be swamped by room acoustics as the bass bounces off every hard surface (floors, ceilings and walls) and takes many differing routes to your ears, each far greater than the distance from rear port to the front of the speaker. That's why I don't think you can hear a difference and I'm completely with Bill on this one; if you want to sell a speaker put the port where people like to see it. People buy with their eyes. That's the simple picture (I'm sure the experts are wincing here at some of the generalisations but I'm trying to be clear)

I hope people building their first cabs at home aren't being put off having a go at building by this It's great to see a range of opinions though. You'll see different designers have differing opinions and the truth is many of us have 'go to' ideas we tend to repeat. The reality is that all speaker cab design is a matter of balancing differing concerns. In the case of port designs it is pretty much impossible to design a really compact high power cab with deep bass that won't have higher port velocities than you'd like. For high power, high excursion speakers you need a wider port to allow it to 'breathe'. Increasing port area for a particular tuning means the port needs to be longer and that both increases the volume of the port and takes it closer to the back of the cab. If you are aiming to have a compact cab then a port of several litres is obviously something to avoid. so you have to compromise. Equally if you have a small cab then the places to put a large port are limited, more compromise. Just look at the RCF PA cabs; generally recognised to be one of the best sounding units available at the moment. Every spare bit of space at the front is either port or speaker. This is just the port of course, there are other tweaks and compromises to be made: weight, portability, target response and so on. then there are practical considerations like the cost of production for commercial designs and the availability of parts for the home builder. If you buy a cab then you are stuck with the compromises chosen for you, if you self build you can add your own tweaks or accept the tried and tested designs so you have a bit more choice. You can see the difference in approach even in this cab. I designed the original box which had a 12" speaker and two smaller ports. That design choice was based upon having a lot of 68mm pipe to hand and the availability of a 68mm hole saw at a price home builders could afford. I check them but I'm not particularly concerned about port velocities as I rarely if ever find they are a problem with bass guitar. My design does chuff with test signals but has never made unpleasant noises with me at gigs (apart from my playing of course) even though it has a 12" driver with greater excursion and power handling. Stevie chose the most widely available and affordable ready made port and that won't exceed unacceptable port velocities under any conditions within the pass band. It's on the big side for a single 10 but it fits and it works. The tuning isn't an issue as that was done by measuring after the cab was built.