Phil Starr

That's brilliant, I still love a build. It would be worth measuring the inside diameter of the drain pipe, It's probably the same as here but we don't want to do a NASA. I still work in mixed units as does most of the building trade. Our sheet materials are 8'x4' and I still have to ask for 4.2metres of 8x2" at my local timber merchant. The tuning is a function of both the cross sectional area and the length, a narrower pipe will be shorter for the same tuning and we can trade off the length with a narrow pipe if we need to. the cost then is the increased risk of turbulence and therefore wind noise in the pipe. 4" should be fine with a single 15 so that is a good starting point. The other material I use for ports are the cardboard tubes that carpets are wrapped around. The warehouses usually are happy to give them away but drain pipe is good and comes in black. I'm getting 7.3cm as the length for the port. Port velocities are high for full power though, That speaker shifts a lot of air. I'll examine tuning and port velocities tonight. I set those tunings to bracket the sensible range it may be that tweaking it a few Hz gives us a little extra. 55Hz looks good but I may as well double check before you start cutting.

It's really interesting to have the US perspective. We've shot ourselves in the foot by choosing to chase off much of our immigrant labour in the middle of a pandemic. I'm sure every country has special circumstances of course but Brexit really isn't helping our problems. Trying to get a feel for how much of this is worldwide and then breaking that down into pre existing structural problems and COVID related ones is difficult enough. Thomann is a German company and ships from there. Clearly Brexit's not the biggest issue if the problem is worldwide but it'd be good to get a sense of what is happening to us.

A quick check of the first 50 bass amps listed by Thomann shows only 23 in stock. 9 out of 23 2x10's in stock, just under half the active PA speakers and so on. It's definitely a thing.

Just in case i forget anything

notes

Drawings Many thanks to @RichardHfor turning my terrible sketches into something good. BC106 (2).pdf

Hi everyone, so as promised this is the result of my lockdown project to make a tiny but usable combo for practising with an acoustic guitar and two unamplified (but loud) vocals. I was also looking to avoid irritating the neighbours and maybe have something handbag sized to take to open mic nights. Hence the title. Here it is, the wine bottle was just used to give you the size So this is a 1x6 speaker in a cab the size of a fuel can with a limited bass response but with good output from then on up. It has good top end, plenty of rich mids and lots of clarity, but with a still satisfying sound. It is a lot louder than it has any right to be. The advantage of using a small driver is that there is no crossover, the speaker is substantially flat until 7,000Hz and there is no need for a cheap and tizzy horn as the smaller driver covers pretty much the whole upper frequency range produced by the bass pickup The technical trick was to accept that the fundamental would be more or less absent but to make sure that all the harmonics from then up were really present. My target was a cab which was as loud as possible and flat down to 80 Hz. Minus 3db is actually 77Hz. Technical spec is Power handling 100W thermal (AES) Frequency response 65-7000Hz -10db (77-6000Hz -3db) Sensitivity 93db @ 1m Maximum output 113db (midrange) Size(cm) 33W, 28H, 19D Weight 4.9kg This is the modelled response the driver used is the Fane Sovereign 6-100 currently £37 from Blue Aran. Materials for the box will be around £20 and a handle, corners and speakon connectors and mounting plate maybe another £15. A couple of independent basschatters have tried the cab and their comments are “That splendid little 6"er if yours I played with deserves a mention. Quite extraordinary, packed a punch for such a small package.” “Vis a Vis the 6" pocket rocket. I had sauntered into the side room out of nosiness and was handed a bass a very solid, Fender P with a few extra bells and whistles, very nice instrument. I was focused on getting a sound I liked rather than on the amp/cab I was going through. There was a line of small cabs dwarfing the even smaller 6" and I assumed it was one or other of them. Genuinely astonished when I discovered which it was. I honestly think gigging with a couple of them would be a serious proposition. Never easy to tell with no kit in an empty room but there was all the good stuff coming out of that tiny cab.” “Yes! What a ludicrous little cab (in a really good way)”. I'll go on to put up proper drawings when I have them and a brief description of the build ply a few more photos

Well my Gnome has just arrived. Ordered from Thomann 6 days ago and no hassle at all, unlike my recent experience of DV24/7, You have been warned. Anyway you have to try it as soon as it arrives (and as I'm typing this the fan has just come on, really quiet) First impressions are that it is a little mid forward and bass light with everything set flat but otherwise very clean sounding. Easily sorted with an eq tweak and I'm only talking about 1 o'clock and 11 o'clock. Actually bass boost on my active P which operates a little lower than the on board sounds better but that might just be my taste. I tried it with my 1x12 which is FRFR and has a huge horn driver crossed over quite low. Sensitivity is 97db/octave so it's efficient without being exceptionally loud. With that it sounds quite sweet as eq'd and rewarding to play, slightly less warm than my Peavey MiniMax but still sweet and punchy. I've turned it up as loud as my ears will take and it sounds great with no sound of overload anywhere on the neck. In the past I've taken this level to rehearsals and had to turn down to match the band, our drummer is a pretty heavy hitter so I'm thinking this would easily handle duties in the rehearsal room and as an on-stage monitor. Haven't tried the DI out but all reports say it does work well so I'd probably never need more than this so long as i had PA support. Small venues would be no problem either. I also switched to my 1x6" practice speaker which is its intended long term partner. I needed to turn it up a little to get the volume from this little fella which is 93db/W and the speaker is naturally bass light, but very revealing, slightly less sweet and obviously needed a touch more bass boost but it is going to blow away people as a combination, they re going to be scouring the stage looking for my amp/speaker and won't believe me when I tell them. the Gnome will drive this speaker to roughness at really high volumes with the bass boosted but only from B downwards on the E string. this is at volumes where i'd be drowning out the acoustic guitar and our vocals though so I'm happy with that a 50Hz filter would be useful though. However that's all about the speaker, the Gnome is providing plenty of power. Both speakers are 8ohms. The Gnome feels really nicely made, a bit more solid and heavier than I expected though others have reported the same. I prefer the look of the TC BAM but the aluminium shell of the Gnome is a utilitarian thing, it's going to help keep the little fella cool and it's doing it's job too, the top plate is warm to the touch but not alarmingly so. The fan seems to have picked up but is still quieter than any of my other amps. So initial feelings are that I'm very satisfied. It will absolutely do for open mic/acoustic sets and as a backup for my main amp. With a couple of 12's giving 4-5db extra i'd have no worries about gigging with it long term and it sounds absolutely fine.

Hi All, I've had a long look at all the various threads I've linked to above and realised that a simple cut and paste isn't going to be as easy as I thought. Some of the parts we used aren't made any more and because the threads were written by different people there isn't a consistent format. Having said that we've only used a limited range of construction techniques and most of the parts can be substituted simply. For example the 'easy build' technique has been used on several cabs and the techniques of fitting grilles, sockets, handles, rounding edges and so on are all just repetition. Would it work well to just have a couple of detailed build threads and building tips here and then separately a good set of drawings and pictures, a parts list, and a few essential details for each design?

OK two more graphs with the same figures,the first just shows the cone excursion at 200W, literally how far the cone moves. The horizontal line is Xmax where the cone starts to leave the magnetic field. The second one shows the effect this all has on the actual volume you can achieve. My rule of thumb is that 120db will let you play with a very loud drummer, (and cause permanent hearing loss in a few minutes.) 100db is going to be very loud in your home and will probably drown out your hi fi. I'm happy to go on helping but at this stage I think it's probably better if you ask questions and I'll do my best to answer. Building the cab in 12mm ply is going to save you a lot of weight. if you are happy with the 55l and 55ish Hz tuning then I'm happy to suggest port dimensions and so on. If you make the port out of a standard 110mm plastic pipe then you can cut three lengths and try all the tunings, and any others if you want something in between but over to you

Ok I suppose I'm trying to feel out what you want from your build and to give you a chance to comment (if you want) on a design. I think you want it small but you don't want it to sound OK and not to sacrifice too much bass sacrifice too much bass, so somewhere about 55 litres is your sweet spot?? So making that assumption, and that you want to use this speaker and want a fairly mellow old school sound the only other real decision is tuning the cab. If you go up 4 posts you can see what 40/55/70 Hz tunings do to the response. None of those tunings are ridiculous but you'd hear a difference. If you tune it higher than 70hz you'd get an even bigger peak and even less bass, personally I wouldn't go that far but you can also go for a frequency between these figures. you can't change tunings though without affecting other things. The latest graph with the dips shows the 'cost' of higher tunings. As you move away from the natural resonance of the speaker in a 55l cab the cab loses control of the speaker and excursion gets too high at high powers. The cone moves so far that the coil exits the magnet and it distorts and can eventually damage the speaker at high power. The dips show where this happens. So the red line shows that the over excursion at 100hz is fairly limited but below 57Hz it if over excursion all the way. At 50hz power handling is only 65W and at bottom E (41hz) it is only 25W. Look at the other extreme, the green line; the over excursion is wide and deep and at 75hz power handling is reduced by half to 100W but from 50hz to 30Hz the 40Hz tuning port takes control of the speaker and power handling is restored to 200W as the port not the speaker does most of the bass making job. So to unpick all this all I'm saying is that you can't have everything. If you chose the best bass response green line you'd tune low, and that looks good for eq too, but you'd lose power handling at 80Hz. If you choose the best power handling at critical frequencies between 80-160hz with the red line tuning then your power handling low down is shot and you'd need to think about an HPF at 50hz if you wanted to crank up the power. if you are only ever going to use this at home though the 25W of bass power where you want it might be perfectly OK. Or you might want to avoid neighbour annoying rumble going through the floor. Only you can decide that. The point is that at this stage speaker design is like squeezing a balloon: every time you squeeze a bit more performance somewhere you have to look to see where the balloon has popped up elsewhere. Once you have the figures in WinISD (other software is available) you can squeeze away if you want and home in what would be the best compromise for you. For me I'd look at this and think the purple line looks tempting, You sacrifice a little bass, but only below 70hz and only a couple of db at 40Hz. You lose a little power handling at 90hz but it'll still handle 140W. You'll never use it at home at that level anyway. In fact I think we are at the point where I'd say a 55l cab tuned to somewhere around 55hz would be about as good as you could get as a compact cab with this driver.

you'll find that the little bit of extra volume makes quite a big difference. look forward to hearing what you think.

Will do, how quickly do you want to do it? I built mine to deliberately match a Kustom Guitar combo which I'd adapted for bass practice. It's slightly unusual construction as a result but I can just give you dimensions to copy right away. If you want to order parts i can give you a parts list too. If you are happy to wait I can get you some drawings done and eventually I will build the combo with the Gnome and have some photos of the build. you can see some of this here https://www.basschat.co.uk/topic/442331-a-house-jam-combo/ the cab starts on P2, there are also a couple of 'reviews' of the cab from the SouthWest Bass Bash here Bass Bash Starts at the bottom of P30

I've got quite a lot of toilet rolls too

Sounds like you have problems your side of the pond then? There's theories over here that by p******g off our closest trading partners we are getting it worse but for me it's the narrowing of supply chains/covid. I used to be able to get output transformers wound locally and there were dozens of people making tubes back in the day but people can't really fabricate chips in a backstreet workshop and we've let most of our manufacturing and expertise move overseas.

Hi John, you'll start people panic buying amps now, people will be stocking up cupboards full of Ashdowns and TC Elves. In fact I panic bought a Gnome a couple of days ago. It's interesting isn't it, lots of people have been speculating about the similarities between the Gnome, Elf and BAM's There are theories that Behringer/Cort and so on might be manufacturing them and badging them. The reality I suspect is that they all use the same chips/electronics and so end up with the same architecture. The same thing that drives the prevalence of the class D 300W/500W amps that everyone is producing now. I don't think people realise how narrow the first link in the chain is. So yes I wanted the TC BAM but it isn't available anywhere at the moment other than at high prices, everyone seems to be looking at a delivery sometime in November with stock due 1 Nov to 1 Dec. I'm also waiting to build some speakers and almost nothing I want is in stock. There are rumours about some TC stuff disappearing and some dramatic price hikes, I doubt they are more than speculation but supplies are tight. I think there are real problems with supply lines but crucially also with production of critical components. I'd also bet that manufacturers have quietly hoovered up critical components as 'just in time' deliveries have become a fragile way to operate. It would make sense to be stocking a months worth of critical components if you have orders to fulfill and factories to keep open with wages to pay. That would reduce the stocks available to people like us.

What do you mean? Only 100W Actually that's my thought in terms of bass on my back and one handed carry. As to my 1x6, well that's yet to be tried, I won't be surprised either way. It's pretty loud but of course lacks deep bass, that's the trade off. Whether that deep bass is essential to accompany an acoustic guitar is the test i suppose. It'll be fun finding out. In fact playing any music live is looking like fun at the moment.

Not crazy at all, unless I'm crazy too (this may not be reassuring) Anyway did you keep the recordings and are you willing to share? That would be a real public service. FWIW last string change I went to change my go-to strings and was ordering four sets of Blue Steels, my hand slipped and I ordered a light set and a heavy set. Just for comparison. I'm very boring with just a P and a J. The J is very bass heavy on the E string and with the P I tend to push the bass just a little so the j got the lighweight strings and the P got the heavy's. Much better than the usual strings in both cases. The J came alive and the P just has a little more 'gravity' in it's voicing. Surprisingly (because I'm quite weedy and also have delicate hands) I really love playing the heavier strings, who knew? I like the Elixirs too but find just a little more life in the Blue Steels. Just taste though, and they do sound similar. I also ran them for two years to track the deterioration both of them ran a year without any dramatic deterioration and i ended up changing the Elixirs first, though the new strings pointed up that the BS's had deteriorated significantly but just sounded nice as old strings. Anyway this is really interesting and i'd love to see more details and hear the recordings. Pretty please

I ordered a Gnome today, I preferred the TC BAM on looks but none were available when I checked, everyone seems to be quoting December 1st so I guess they are all hoping their ship comes in. Given delivery I decided to go with Thomann who say they have Gnomes in stock. I want this for a specific reason, I've built a 1x6 cab for open mic and working with acoustic acts and I want to turn it into a teeny-tiny combo. The 1x6 handles 100W so this will be ideal. I had intended building an amp from scratch (OK from ready built modules) but factoring in the costs of a case and connectors this works out at a similar cost. I'll put up the design for people to copy when it's done. I will of course try the gnome out with all my assorted speakers and will gig with it when I get the chance. November's gigs have all been cancelled.

Here we go. It's pretty clear that the higher tuning improves power handling at all but the lowest frequencies. At 80hz the power handling of the 40hz tuning is reduced to 100W, but at 50Hz only the 70Hz tuning is incapable of handling the full 200W thermal rating.

Another coffee break, so looking at the graph above a 1db difference is only just going to be noticeable but there is a 2db peak with the highest tuned cab which is really going to warm up the bass, pschoacoustically we hear this area as bass and this is the sort of response a lot of the old 60's cabs often displayed. Quite a few modern cabs too, if you like MarkBass with the tweeter disconnected this might be for you. the problem might be with EQ. If you have a traditional bass controlthen boosting it to get a few extra db at 50hz might well give you problems at pushing that 120Hz peak even higher. At the other extreme the lowest tuning has a slow roll off which starts quite high and that will probably sound quite good with some gentle bass boost. The middle option looks interesting, just over a db more at 80Hz up to 120Hz and the same output at 50hz. there is a hump but at less than 1dB it isn't going to be significant. Of course this is only frequency response, if you want to use this cab at gigs we need to look at how tuning affects power handling.

Here we go, I'm doing this at coffee breaks which gives an idea of how quick WinISD (and other modelling programs) allow you to work. For this I've done my usual routine of making a basic assumption and running through the options I know are most likely to work. For this I've assumed you want it as small as practicable and to me that says 55litres. This graph looks at tuning and I've tried 40Hz,55Hz and 70Hz (green,purple,red) That doesn't tell you how it will sound, but i'm specifically looking at two things here. How quickly the deep bass rolls off (below 80Hz) but more specifically how the cab shapes the response above 80Hz. I find it most useful to look at the area of the graph rather than any specific point on the graphs but then ask myself a few specific questions. As you can see the higher the tuning the more bass you get in the 80-160hz octave, that's counter intuitive but you can see you lose out at 50Hz so you are trading rich harmonics for weaker fundamental. I can see other people are reading this thread so if you feel I'm being over pedantic, well I can't forget I used to be a science teacher

Peavey Scorpion 15.wdr I really liked the cab you showed with contrasting timbers forming the corners. My 15"cabs are only 350mm deep and using something 25mm or so all round each panel in a contrasting timber could look quite good. That would enable you to have a really big radius on the edges too if you wanted. It looks like that is how they made the cab you have shown. I know it means extra work but if you have a biscuit jointer it shouldn't be too hard to form. I don't know where you live but round here you can buy bigger timbers and even get them to make up larger jointed boards at a price. Alternatively I've used veneered panels with timber edges to make up cupboards and they can look quite good. All this looks expensive though, unless you have a supply of well priced timber or have a lot of off-cuts in stock. Are you sure this is the best place to start? If I was going to invest maybe £100 on timber and quite a few hours work on the perfect cab I'd want the perfect speaker and I'm not sure the Scorpion in a 50l cab is that.