Phil Starr

There's one other difference between the cabs that you don't mention. Bill's is a commercial design and so you get detailed instructions and a level of support you don't get from our 'amateur designs. We can help you out on details if you get stuck but there isn't anyone full time able to do everything. 15mm was specified as the right balance between weight saving and rigidity. 18mm and 12mm are what the big sheds provide as standard. 12mm is lighter but you might get some panel resonances and need a bit more bracing. 18mm a little stiffer and you could possibly use a different bracing but we haven't tried and tested anything other than 15mm. It's not a huge risk building in either; both will work in the sense of giving you a decent sounding cab but you might need to do some fettling after you have tested it to get the absolute best out of the ply that you try. Stevie specified poplar ply for his cabs and bought high grade ply for the final iteration. Good quality 12mm hardwood ply might not be too far short in terms of performance, we just haven't tested it. The advantage of a self build is that you can choose the back panel of your choice, with an 8ohm speaker I'd always use a double socket so that I could daisy chain a second speaker but that is a choice for you. Our problem is that if we specify every component then designs become outdated as soon as one of those becomes unavailable. You can get carried away with wire. Almost anything you use will have better current carrying ability than the very fine wires used in the speaker coil and they aren't long enough to have a huge resistance. I've more or less settled on standard 42 strand copper cable but it's not unknown for me to strip out the conductors from 13A mains cable and use those if I've nothing else to hand. As to glue again don't get too hung up about it, almost any glue will be stronger than the wood. PU glue is horrible to work with and if you have gaps to fill you can always go back to them with mastic and seal them. If you use PU to bridge gaps then it loses strength. This isn't really about the right or wrong of a particular adhesive just about practical solutions. If you possibly can ring around and try and find someone to cut the six pieces that make up the cab plus the two large pieces that make the main braces. I've built many cabs using the tools you have but unless your table saw has a sliding table it's unlikely you will cut 100% accurately on your first attempt. Even that isn't the end of the world as you can fix most thigs with a lot of sanding and maybe an extra trim but that bit isn't a lot of fun, working with accurately square cut panels is fun

Sadly that is how most bands see bass. It has a function in the band of holding down the rhythm and defining the chord changes. To be fair that is what most songs call for in most genres. If someone else is soloing they really just want to know where the bass is going to be so the soloist or singer can concentrate on what they are doing and know if they get lost someone in the band is there to help them get back to where they need to be. Even if you play Jazz or Funk mostly you'll be playing a groove over a simple chord progression and with a new band you'll need to demonstrate that more than trying to duet with someone you've never met before. Good luck with the next try out you get

Hey Steve, still after more volume It’s hard to tell just from the specs how good these will be and how well they will integrate with your RCFs. They are remarkably cheap for something with what looks like a decent crossover, a power amp and 15” speaker. It’s hard to see how they could have spent much on the speaker and it is likely that it will have restricted excursion or an undersized motor system. However it is remarkable just how much some of the cheaper gear is giving you nowadays for your money. On the plus side they will allow you to get more out of your tops and our ears aren’t very sensitive to bass so it is always surprising just how much modest subs will add to your sound. If you are lucky they will have DSP protected the speakers from over excursion so you shouldn’t have to worry about pushing them. These look so like my Wharfedale subs I checked to see who owned HH, it’s actually Laney. That’s probably good news as Laney are making a lot of solid old school kit. We pulled apart a Laney PA speaker recently and it had quite a decent class A/B amp in it. For the price it sounded great. If you are lucky you might have bought an unremarkable but well priced and specced speaker. Really interested in how you get on with this in practice. Gigging up near the Somerset borders soon?

It's actually a very good question. Yes in theory, but that little chamfer wouldn't probably be enough to be significant. There are plenty of successful designs that have compromised ports but which still work well without obvious problems. It's just one of many aspects of design where there is room for disagreement. @Stevie and I disagree slightly about this and works hard to avoid any chuffing in the ports. I'm more relaxed because it has never been an issue for me at a gig and I haven't noticed it when other people are playing. The reality is that there is very little fundamental coming out of the pickups in a bass guitar so designing for really high levels of those frequencies is like designing houses for a once in a hundred year flood. It might never happen but there are ways around it, you have to consider the odds and what the consequences would be if it happens. In this case it is a bit of distortion on the loudest deepest notes if the amp is right up and you are applying lots of bass boost. WinISD calculates the port air velocity and I did look at it, it's not perfect but I tried a range of port sizes for you and this is the biggest port that easily fits in your cab. Any bigger would reduce the chance of wind noise but would mean constructing a port longer than the cab is deep. That means either a folded port with other problems or changing the shape of the cab so your 19" amp would overhang. When we were discussing this Stevie was able to demonstrate chuffing at very low power in one of my older designs. This was with a test signal at 50hz and I think around 20W. That's alarming but I never heard any chuffing in use from that cab before or after that cab. That's the day we found that one big port is less prone to chuffing than four little ones. My ports still tend to be smaller than Stevie's but I'm now much more likely to use a single port and as big as possible. So there isn't an absolutely right answer to this, all designs are compromised and different designers worry about different issues. I'm not anticipating that this will be a problem for you.

Looks like @stevie and @Chienmortbbhave answered your questions. If you look at the crossover it has two parts. The one to the horn which matches it's output to a single bass driver, it wouldn't match the increased output from two bass units. The bass section doesn't match two units because the combined impedance would be 4ohms not the 8ohms it was designed for. You could do a version that John alluded to. A 112 and a 112T with the problems that he mentions that the 112 operating without a crossover would have midrange output that would 'interfere' with the carefully controlled midrange of the 112T. That's not to say that it might not sound nice, just that the sound would be unpredictable. If I wanted to go that route I'd build two cabs, one with the horn and one without. You'd effectively have the FRFR/hi fi sound of the 112TMk3 with the old school sound of the 112 with the possibility of increased output and a third sound when the cabs are combined. We never tested this but I'm like John/Chienmortbb on this, it might sound quite nice. As to the port, well you could simply shift this to the central position but retaining all the dimensions of the cab I gave you. It would certainly help brace the cab. Personally I don't like the symmetry of that arrangement, with both speakers the same distance from the port any resonances would be likely to sum. Like so many decisions in cab design there are wins and losses to be made. You asked for a slot port but actually a round port of the same area would be better. Turbulence in the port causes chuffing at high volumes. You get turbulence at the edge of the port because the surface causes friction in the air movement. A round port has the minimum outside edge for a given cross section so reduces turbulence. That's why I don't like the narrow vertical ports some designs use and put the port on the bottom. It's also easy to construct that way.

Good advice, it may also be something trivial like a broken wire or an internal connector come loose. A bit like replacing a car because the fuel line is blocked. Find out what is wrong first, then decide.

I've tried both the Behringer 205 and the TC VoiceSolo, they both work after a fashion. They are built to work on a mic stand but that is a bit of a nonsense as they make the stand too top heavy for anything but the most tame of gigs. They both are loud enough to cause feedback so extra volume isn't useful. The Behringer sounds like a very loud portable radio the TC is much cleaner sounding but as a practical proposition for vocals only the behringer works better as the mids are what you need and you will get early high frequency feedback from the TC IME. I sold my Behringer to my drummer so he could hear the vocalist and he liked it, with no vocal mic he could position it close and no feedback. For monitoring my backing vocals they are only OK if your drummer is loud. The gain you need to hear yourself over the drums is enough for anything that close to the mic to cause feedback issues. It's just good enough to pitch but that's it once you've cut it to stop it howling. (some say my bv's are howling) I lost them when I started using an RCF ART310 as a floor monitor. The much flatter response and the floor positioning allow all the gain you need. I'm losing my hearing, too much exposure to high levels of sound. Too late I'm turning to IEM's they don't just give you the sound they cut the sound level at your ears to levels that don't cause damage. Using earplugs is a matter of fit, I struggled with poor bass, falling out and tight uncomfortable plugs. All of these are cured by well fitting in-ears. I thought I'd feel cut off from the audience, you'll be amazed just how much audience sound comes through the vocal mics. On a good day I get hi-fi/studio sound through my in-ears and my playing has improved because I can hear everything. I wish I'd done this when I started gigging and if I could pay £20,000 to get my hearing bck to where it was 15 years ago I'd take your arm off. Do yourself a favour and try some nice comfortable over-ears in rehearsal where no-one cares what you look like. Once you get that set up how you like it you will want that at a gig. Even those little Behringers are going to damage your hearing.

Bad luck, it is horrible when that happens. Before you rush off and start spending it is worth spending an hour or two checking what actually went wrong. It could be something simple you'll spot if you work through logically and without all the pressure. I don't think you checked your speaker lead for example and I'm not clear if you tried just going straight from bass to amp. Speakons often have screw terminals that work loose over time so there are a lot of very simple things it could be. If it is indeed the amp then it could be repairable. I can't say I stay rational and organised in these situations even though I know a cool head can fix most things You'll want to take a backup at least until you are confident about your amp. I have a Warwick Gnome which sits in my bass case and I also carry a DI box to gigs. Sansamp, Zoom B1four, there are loads of options.

God is there more than one or does he commute round the country

You've heard me play then 🤣

The Jack is an unusual design and has been optimised to work with specific speakers. To be honest I'd expect Bill's advice to be the best advice you can get if you want to build one of his designs.

I've not used either of your suggestions but by all accounts the PJB has a great all round sound. It may well have a flatter response in the bottom octave than an 8 but at the expense of efficiency and ultimately volume. I'm using a different system for this purpose. A Warwick Gnome (TC BAM or an Elf would work as well) with a 6" speaker. It's tuned to give a very respectable volume and a flat response down to 80Hz (there is very little actual bass 40-80Hz coming out of a bass pickup) It has a very satisfying sound, light agile and detailed, which is great for practice as the detail is what you need to hear nd the lack of subsonics reduces the noise carried through floors and walls. If you are handy with wood all you need to know is here House Jam Micro Cab - Amps and Cabs - Basschat https://www.basschat.co.uk/topic/455858-house-jam-micro-cab/

@Happy Jack has pretty much nailed it. I used to run a jam session. You should understand that most Jam Sessions aren't really a free for all. there is usually a core of people who form a house band with vaguely rotating members. The organiser is usually being paid a few quid by the pub and so they have to make sure the music keeps on going and are at least not driving the other customers out of the pub. I had a couple of singers who would usually give me advance warning of what they wanted to sing and I'd have chord sheets available for some of the songs. Most popular songs have three or four chords and simple structures and anyone who has played in covers bands will have a few songs in common. Any 'jamming' is usually a guitar solo played over a single chord or either a verse or chorus repeated for far longer than is sensible I had a lot of bands come along and play half a dozen songs if they are 'between' gigs and a couple of acoustic acts who would just do their thing but borrow bass and drums. As for playing bass at these things, I'm the worlds worst improvisor and played some shocking mistakes. No-one seemed to notice, too busy dreaming up their own mistakes I guess. I prepared as best I could, made a note of songs I hadn't heard before and looked up the chord sequences. Keep the playing simple, root note only or root fifth. The most I would do would be simple 3 note arpeggios but the root is your friend. Oh and don't forget you can use dead notes when you haven't a clue what the guitars are doing. I loved it when the guitars were playing full chords for a song. If you recognise the chord you know what the root is, barred chords are easy to follow.

My bass practice has stalled and my tea has gone cold as I've disappeared down another rabbit hole I'm a biologist by training and chemistry was my second subject at university, I started to fact check and bamboo is way more interesting than I imagined, and my chemistry way more rusty than I realised. So to summarise bamboo has a very different structure to wood. It is made of similar cells arranged in a different way. The conducting tissues are surrounded by bundles of fibre cells which give the stems their stiffness. These cells are longer than most similar cells in woody tissue. There are lots of these fibre/conducting bundles in the stems and they are surrounded by parenchyma cells, these are softer cells and they strengthen the structure by absorbing and spreading forces on the fibres. Mechanically this is very like fibreglass. It goes beyond this. The fibre cells have walls which are made of strands called fibrils, as are all woody tissues, but bamboo has evolved a few extra tricks. The ratio of lignin to hemicellulose in the fibrils shows higher levels of hemicelluloses which are less strong than lignin but the mixture is stronger than lignin alone as the hemicelluloses create strong hydrogen bonds with the lignin. The hemicelluloses also have microfibrils which increase the strength of the fibres. Article in Nature Bamboo is a grass, not wood and it has lots of exciting possibilities. It grows quickly, maturity in 4-5 years and not decades like wood. The plant survives harvesting. The 'waste' can be chemically treated (breaking those hydrogen bonds) to produce long soft fibres softer and stronger than cotton. The technology is young and developing so the price may drop as it is scaled up. Whether monocultures of bamboo prove to be better than monocultures of cotton and spruce/fir is a potential issue but bamboo is more productive and may be able to address the shortage of timber in the construction industry. Certainly growing a fibreglass like material as strong as steel sounds promising. For bass cabs the Youngs modulus/stiffness thing could mean thinner cab walls and lighter cabs. I don't know how easy it will be to cut/drill/glue/shape. The density isn't an issue, it's lighter than some hardwood ply not as light as poplar. I think at this time it's wait and see. Will availability improve and the price come down? It's great we have one entrant into the bamboo cab market. If it is successful we'll see more.

This sounds right to me too. Early on Tommy was experimenting with a range of drivers and sold off a few of his trialled drivers here. I tried to buy some of them. I got the impression at the time he had settled on eminence.

It will. The Kappalite has a more powerful magnet system and this damps the movement of the speaker more than the less powerful motor system in the Deltalite. This means it works better in a smaller cabinet. The kappalite is the speaker to beat for a tweeterless 115 for me and something I was considering for a Basschat design, and my own use. It's the basis for the original barefaced cab and a great choice used by a lot of other people. Not only does it have an excellent bass response but a wide flat upper mid peak that will sound quite musical. If you are serious about a build then why not start another thread and we can maybe do something there. Hopefully you can put up some pics of the build and encourage others to have a go at a self build Best to tag me on that thread as I've got a new band and don't come on quite as often as when I'm with an established band or between bands.

We seem to have wandered off a bit from Al's first post but it is great to have a place to discuss PA Just something to think about really when discussing putting the PA at the back behind the players. It just isn't a great idea really. I'm a pragmatic person so I'm not saying it can never work, I will say it is never the best solution in terms of how your band will sound. Two reasons for this. The PA is louder than the human voice. If it isn't why would you use it, just sing. If you have anything other than an acoustic band the band is likely to be louder than the vocals and even though the mic is much closer to the singer than the rest of the band it will pick up everything in it's line of fire. I have meters on all channels and those vocal mics are busy all the time even when the singer isn't there. A hit on the snare registers at the same volume as the singers voice. You need to get a clean sound from each musician to get a good mix so moving anything away from the vocal mics is good. Don't put the PA at the back, keep it in front where as little sound as possible leaks into the vocal mics. Point everything back line away from the mics if possible. I've mixed for bands that are so loud on stage that there is no point in the set where the singers voice matches the instruments in the vocal mic. Secondly there's a thing called 'gain before feedback' link. It's basically very simple, how loud can you turn things up before feedback. There's loads of components to this from the acoustics of the room, pickup pattern of the mic, how flat the frequency response of your system is, how loud the rest of the sound is and so on. It's quite possible that with a singer with a loud voice you can turn down the gain and they can go into the audience. Or turn down the gain and just be quieter. Or just be in a perfect room with no little acoustic problems but eventually if you turn up loud enough your PA starts screaming. A column may well have a flatter response than a poorly designed horn and a more predictable dispersion but that's as much about the quality of the system. A good horn system will beat a poorly executed column. Putting the speaker at the back was a bit of advertising from Bose written by the marketing people. Putting anything behind the vocal mics just decreases the gain before feedback over placing them in front. Something you can possibly get away with but never a good idea.

I've a 115 design at home with an Eminence Deltalite as the driver, I think I can do better with the choice of driver but if you are happy with building a one off at any stage I'm happy to share what is work in progress. i've a 1x15 design

Yes I used WinISD for the calculations/modelling. The results are around what I expected but the program makes a number of assumptions about the design which can put the tuning out a little. When we do this as a 'proper' BassChat design we also check the T/S parameters by directly measuring them. So far the Faitals have proven to be pretty much on spec but that isn't always true of every speaker.

OK we have a design, c100litres with a slot port at the base of the cab. Using two Faital 320's 83cm H, 51cm W and 36cm D. The port is 6cm high and 19cm long. i've tuned it to reduce the bass hump to just 1db and managed to extend the bass so -10db is 41hz. Coincidentally that is bottom E. Internally the dimensions are 80x48x30cm. Sensitivity is 98db/w and it should achieve a slightly scary 126db in real money.

It's so hard to be certain of the lifetime environmental cost of any timber products. US and European standards are pretty good and reasonably well controlled, though conservatives both sides of the Atlantic have cut back funding for inspection and enforcement agencies. Italian Poplar is to be trusted I think but for us over here it is more complex. Most of our 'Baltic' birch is Russian and only the outer plies are birch. A lot of 'Poplar' is made in China and is cored with either Populus yunnanensis or Eucalyptus deglupta and faced with Eucalyptus grandis or other hardwoods that may be sourced from elsewhere in South Asia. If you are a manufacturer buying in bulk it's reasonably easy to track back your timber but it's harder if you are buying a single sheet from the local hardware store. Bamboo looks to be a fantastic resource as it grows to maturity in 4 years or so and can be continuously harvested as the roots remain, a bit like the old coppicing system with hazel and chestnut, or more accurately like mowing very long grass. It will be interesting to see what they do with the waste (about 70%) what inputs are needed to maintain the growth and what problems large monocultures bring. I'm not cynical about this and almost any product made by photosynthesis has to be better than mining or manufacturing. I'm with you in recognising that FSC certified timber is already a 'green' material. I'm sceptical that some of the green hype over bamboo might be a little overdone. The devil is in the detail.

It's an interesting proposition. £100 a cab is expensive but for something high quality not completely prohibitive. Poplar worries me because it is soft and not too rigid so a harder material would be attractive. What I don't know about is workability and how it takes glue and finishes. You would still need some bracing and that tends to have a small glued surface so that might be an issue. If I do it there are people selling smaller panels on Ebay and I'd want to work with that first. I've also picked up a bamboo chopping board from Lidl. I'm going to make a cutlery drawer out of so it will be interesting to see how easy it is to work with

Interesting, so there are quite a range of differing bamboo laminates available. I haven't been able to discover the actual resin they use to bond the material but it is described as D3 which makes it shower proof but not fully waterproof and suggests it might be a PVA. In any case there is no problem with the release of formaldehydes when the boards are cut and shaped. The density is 0.7 (where water is 1) that compares with many plywoods but is heavier than poplar ply. It is very rigid though so you should be able to get away with thinner boards. It is also much harder than most woods so should handle knocks much better. the downside is that it is much more expensive than most plies, An 8'x4' sheet of 12mm board is around £200, enough for two decent sized cabs.

I need to get on and do some research. The fibres are used in some speaker cones but I’ve no idea how the bamboo is formed into sheets, they are really stable though even when wet..

It's potentially a great material, rigid and light. I've been eying up some of the bamboo laminates for a while as a potential cab material. Just need to find it as a sheet material, making a cab from Lidl's chopping boards has even been under consideration as a proof of concept.