Phil Starr

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.

It'll be a slot port as requested on the bottom of the cab. I don't like narrow slots so the barefaced vertical port is not ideal IMO, even if it looks aesthetic. That makes this a tall cab and with the 19" top it more or less designs itself. I only need to find an hour or so to fiddle with volumes and tunings and the design work is essentially done.

That's great, it means your cab is almost designed. the original Basschat Mk1 1x12 was designed for a 19" amp so basically you'll be getting two of those. If I remember it weighed about 11kg with ceramic speaker magnets. Yours should come in well under 20kg with the bigger cab but lighter drivers.

Last graph for a while This one shows the Faital 320 in three different sized boxes. The pink is the 50l box, red is 85l and green is 35l. This time the boxes are tweaked to get the 'best' out of each box. What you see happening will be true of any speaker put in different box sizes in general terms. The larger box allows the best bass response in that it is flatter and goes down lower. 85l is about perfect for this speaker in that respect. -3db is well below 50 Hz and -10db which is what most manufacturers quote is pretty close to the fundamental of bottom B on a fiver. Putting any speaker in a smaller cab introduces the bass hump and the smaller the cab the higher the frequency at which it happens. It doesn't show well in this graph but the peak gets higher too. The thing is that for a bass cab more bass isn't really a universally good thing. Our ears don't pick up sub100Hz very well but mics do so the vocal mics will amplify this bass even though we can't really hear it and the PA will quickly start to struggle. (use the 80Hz filters guys) If you are stuck in the corner those bass frequencies will be boosted and you might well start to excite room resonances. In listening tests we carried out with bass players most bassists thought the pink response was 'bassiest' not the red one. Only about one in three recognised the extra deep lows of the red response. That is bass players, most of humanity gets bass information from the second harmonic in the signal 80-160Hz. So now the question. How big do you want the cab to be? Given the trade off. I can give you the Pink response in a 100litre 2x12 using this lightweight value for money driver. I can get an extended response in a smaller box by using a speaker with a bigger magnet. Or I can get the box size right down with the pink response with the right driver if I can find one. A 100l 2x12 isn't huge but it is substantial, a few years back it was around the norm but with cheap drivers and for me a bit too much of a warm sounding hump. If you leave me to it I'll design around the Faital 12PR320 and try and optimise size and response but I think physics will push me to an 80-100l cab. If you want something smaller I'll look for another driver, though the perfect driver can be hard to find.

Outed

OK I've managed to grab a few minutes and I'm looking at the Faital 320 as the speaker to beat. So I'm looking at tuning first I can shape the response by tuning the port to differing frequencies, in this case gold is tuned to 45Hz and the purple to 55Hz. Tuning higher gives the raised hump at 90Hz and the lower tuning gives an almost flat response. For me a 3dB hump is just too warm and woolly 1db is just noticeable so 2dB is kind of where I'd like it to sit. But, it isn't just the response that is affected. The software is adding the output from the port and the speaker itself and when th port is active it is damping the movement of the speaker. That in turn affects power handling. So this graph shows the power handling. You can see the power handling is restored to the full 300W of the thermal limit where the ports are tuned at 45 and 55Hz in the different tunings. The dip above this is because the speaker excursion is beyond the limits the speaker can handle. What's going on here is the coil is moving outside the safety of the magnetic field. So at 70Hz the power handling is reduces to 120W at the lower tuning. I'm going to be looking at every aspect of the speakers behaviour even though I'm going to be talking about bass response most of the time. I might come up with a recommendation that looks sub optimal but in the background I'll be trading off gains in one are against a cost somewhere else. Speaker design is a bit like squeezing a balloon. Solve one problem and another one pops up elsewhere

It was always our hope that these designs would last for many years so it is great that you are building this we hope that it will stimulate others to do the same.

When the time comes we have other cab designs on BC and if you want to build a custom there are plenty of people to help if you need it. Got to be easier than the EBB5

all ported in 50litres and I think tuned to either 60 or 50Hz, my computer crashed and i didn't save the files. I do a lot of this when selecting drivers. In the olden days I'd have standard cabs and just swap speakers now I usually start with a 50l cab for 12's and a 30l cab for 10's and computer modelling which lets you cover a lot of ground. you can tell pretty much from the T/S parameters what you expect but it's really easy to see the graphics. Once I've got a driver selected I'll tweak the cab volume and tuning but you can only move the envelope so far.

Yes it is compatible and will be a lot louder than your current speaker. I used one of the MK111's with a Peavey 2x15 and it sounded great. The big question is whether you want to lug such a big speaker around, only you can answer that. I don't think using the force will help you get it up a flight of stairs Not many people are prepared to carry such a monster nowadays so you should be able to get it at a good price.

The Red plot is the Kappalite John it gives a flatter plot in a smaller cabinet but I used the 50l cab as it was one they all worked in. Since we know @JPJlikes a warm old school sound I'll go back and look to see what's available that might be better than the Faital. Actually since you've been using the Faital how about telling us what you make of the bass response. Though I suspect @stevie will have tuned it lower in a 2-way cab.

OK that's good, I'd have gone for the Kappalite's myself. So we've eliminated them. Although I could force a hump into the response by reducing the size of the cab. If you want full on bass and not too much else you could go for the Beyma's if you are quick as there are still a few available but the Faital 320's are great speakers and have that upper midrange lift of an old school speaker, well within your budget and lightweight too. I'm not sure if @RichardH has the same speaker I have at the moment but mine has the the Faital and one on its own gives you a real punch in the stomach. I'll have a better look at that and see what I come up with.

This is where it gets interesting. This shows the maximum output the speakers can make. All of them have a dip centred around 80Hz. This is normal and is due to excursion limits. The speaker has to move further for low frequencies and below 50Hz none of them can manage the excursion. At 60Hz the port is making most of the sound and the speaker movement is damped by the port so they can all do their thing. At low levels over-excursion just manifests itself as distortion, at high levels it can destroy the speaker or lead to the coil overheating and reduced output or power compression. Over excursion reduces the power handling of the speaker. The Kappa comes out best with only a tiny dip which would be inaudible, The Deltalites have a significant dip of over 6db and the power handling before distortion drops to 60W. The dips in the other two aren't anything I would worry about but the Kappa is definitely going to give the tightest sound in this box. The Beyma is the strange one as it is 6db louder at 40Hz than the others in this box. I don't think a 40Hz output is musically useful in a bass speaker. our hearing down there isn't very good but it can excite room resonances and muffle the bass. In a band setting I prefer those frequencies to be left to the drums with the bass filling the gap between kick and the other instruments. If I'm mixing and the desk allows it I'll filter the bass at 50hz and my ideal sound is flat between 80-160Hz. If I'm designing a small speaker I do design in that extra warmth a mid-bass hump gives to compensate for the lack of bottom end. In listening tests most bassists however seem to like the warm bloom in their sound. It's a bit marmite though, you love it or hate it. At this point then it's a matter of taste. For me at this budget point I'd go for the Kappa, The UK prices for Eminence speakers has recently improved so they are competitive again. I like a tight articulate bass sound and would roll off the bass at the lowest frequencies anyway. However it is a matter of taste not right or wrong. The other thing is that of these speakers all but the SM212 have a midrange peak that livens up the sound of a single driver, effectively the Delta and the Faital have a mid-scoop, the result of that low hump in the bass and the mid peak. They sound like a bass speaker. The SM212 has a flat but extended mid/top and sounds more neutral. I gigged with it for years and you just have to eq differently but I've moved on to cabs with horns and I'm happier with that. So you have lots of options but the first choice is nice warm old school or tight and articulate bass.

Mixing speakers is a bit of a lottery. No speaker is truly flat and the character or timbre is a result of all the lumps and bumps in the response. With two speakers the peaks won't line up and the combination will create a completely different set of highs and lows. You'll lose the character of both speakers. On top of that you'd have to match sensitivity and speakers have to be matched to the box so you'd need two boxes.

OK this is the frequency plot for 4 speakers. The Kappalite used by Barefaced (red) Beyma Sm212 (blue) Deltalite (purple) and the Faital 320 (green) all in the same cabinet 50litres. You know what the Deltalite's sound like so that gives you a starting point. They have a peak around 120Hz of about 2db which is colouring the bass and the bass rolls off slowly from there. The Beyma has a similar peak slightly les high than the Delta's but has the highest output at 40Hz of all the speakers. The FAital has the highest peak of all, around 3db and the highest output between 50-100Hz. the interesting one is the Kappalite with the most powerful magnet it has the flattest response down to 70Hz and then rolls off more quickly that the other speakers. Remember this is just the bass response up to 200Hz so not the whole picture. Remember these are all in the same box, they can all be put in different boxes, the beyma would love a larger box and the Kappa would be better in a smaller box, or i can tune the boxes differently and shape the curves a little. Despite this I think it is fair to say the Beyma is going to have the deepest bass and the Kappa is going to be the most honest speaker with all the rest tending towards warm sounding.