stevie

Hi B.Flat. No, it doesn't really change anything. That's what I expected.

One of the keys to getting an active crossover to work properly is making sure that the drivers are flat an octave either side of the crossover frequency. At the moment, your 2x10 cab is rolling off just below 200Hz. This will produce a phase shift which in all likelihood will result in an unwelcome suckout in the very important 100 to 200Hz region when you pair it with your 15. This will happen whether or not you use an active crossover (unless you use asymmetrical slopes, but let's not get into that). The OP can get a good idea of what this sounds like simply by running both cabs together as they stand. I think the original suggestion was best. Although it's true that these drivers need a larger cabinet, if the OP ports the 2x10s as originally planned, he'll extend their frequency response down another octave or so, which will allow the crossover to work (more or less) as intended. It will also give him the opportunity to run both cabs together without a crossover. I am assuming you have a stereo power amp. (You shouldn't have any chuffing problems with two 4" ports). Using a crossover on your 2x10 means that you are potentially reducing system power handling by half because the tens are not handling any bass. Carrying a 70-litre midrange cabinet around with you is just silly. Plus, you would have the added flexibility of using the 2x10s on their own and taking the 15" cab along for the occasions when you need the extra oomph.

I wouldn't count your chickens, Peter; I don't see a queue forming yet. As far as an amp if concerned, I do know that Chienmort uses a lightweight 100W into 8-ohms amp (Gallien Krueger?) with his cab and it is very loud.

By the way, I've just realised that this cab design can be assembled without any screws or clamps. Details in the next set of photos.

Good man! If we get a bit more interest, I'll put some feelers out.

Now that the final circular brace has dried, I've glued in some small bracing pieces which really make the back panel solid. I've just placed the baffle on top, but you should be able to see that all you need to do now is clamp or screw the other external panels in place around the "skeleton", and the cab is finished. Apart from all the hole cutting, this is a really easy build. This is how a Kappalite driver fits. The final job for today is to drill the holes in the baffle for the t-nuts, and then I'm taking a break. More next week......

Here is the piece cut, drilled and glued into place. I eventually removed the clamps as they did more harm than good. Simply putting the bracing pieces firmly in place, lining them up properly with a right-angle guide, and using plenty of glue, works best. As the glue sets it shrinks slightly and pulls the pieces together.

Now we come to the final circular brace. I've used an offcut, but it would help if the wood supplier would also cut this piece to the right size. I'll see if John can alter the cutting list to include it. I've marked the piece up ready for cutting and sawing. [PLEASE NOTE: I LATER FOUND THAT THIS BRACE IS OVERKILL AND NOT REALLY NECESSARY. HOWEVER, THE FRONT PANEL DOES NEED A VERTICAL BRACE BETWEEN THE OPENING FOR THE HORN AND THE PORT (AS SHOWN IN CHIENMORTBB'S PHOTO - 50MM DEEP IS PLENTY). AND THE TOP PANEL SHOULD HAVE A SIDE-TO-SIDE BRACE AS SHOWN IN THE DRAWING.

Glad it's of interest, fftc. Gottastop, I'm building this cab for myself. So I'm going neo. The original drivers were selected with performance and price as the priorities, with weight a secondary consideration. This time round, I'm just interested in performance. The neo drivers I have are actually heavier than the Beyma/Celestion combination of ceramic drivers, but their performance is in a different league. I have a Ciare 500W 12" neo driver with a 4" coil and a DAS 1" neo compression driver with a titanium diaphragm. Both were eBay purchases and would have cost about £350 otherwise. I've also changed the horn to an asymmetric type, which is perfect for bass guitar use. There aren't any similar-sized commercial cabinet on the market with comparable perfomance - as far as I know anyway. I've gigged this design with the prototype cab and found the weight a bit offputting. The poplar ply cab I'm building now will be much lighter - so we'll see how it goes. If the weight is still a problem, I also have an Eminence Deltalite OEM variant from an American bass cab (can't remember the brand at the moment) which is pretty good and will save about 2.5kg overall. This is obviously of no interest to anyone wanting to build their own, as none of these neo drivers is readily available. However, Faital Pro are about to bring out a new 12" which ticks all the boxes for a killer bass cab. I've been talking to them about it and will receive a sample as soon as it is released. I've also negotiated a special price which I can pass on Basschatters if we get enough people interested - say about ten. I would then publish the design on here for everyone to use - using this cabinet. I'll provide more details if there's any interest. By the same token, if there is enough interest in building this final version of the cab, I'd be happy to negotiate with some CNC builders on everyone's behalf. We'd probably be looking at a minimum order of ten flatpack cabs to justify the CAD setup costs. As I am putting this cab together, I'm finding that the most time-consuming jobs are drilling and cutting the holes in the panels. I've just drilled the holes in the baffle for the main driver, and it took me half an hour - and I've not even inserted the t-nuts yet. A CNC'd cab could be assembled in a couple of hours over, say, three evenings and would require no woodworking expertise at all.

Second circumferential brace glued in place. One more brace to go. It's starting to take shape now. That's my right-angle guide in the bottom left-hand corner.

By the way, all of these panels were cut by the wood supplier according to the cutting list on page 1. Now to glue our second brace into place. This was tricky, because the clamps pulled the brace in different directions. After a lot of fiddling, I managed to get it into position using four clamps. I was missing the obvious, however. I should have learned my lesson when I glued the first brace into place: you do not need clamps for the braces. You will need some kind of right-angle guide when you're gluing the braces in, because keeping everything at right angles is crucial.

The figure 8 brace connects the cabinet side walls together with the front and back, and is the most important brace in terms of overall rigidity. Now on to the second brace. This one can't be a figure 8 because it goes directly behind the driver. The idea is tomake it as close to a figure 8 as possible by cutting out a space into which the driver will comfortably fit. Then cut holes for air flow without weakening the structure. I'm using hole cutters because they're easy, but a jigsaw works well too. Mark it up first. Then cut. I have rounded all the edges using a powerfile and sandpaper to improve airflow somewhat, but I expect it's not really necessary.

Just listened through a Creative 0202 USB soundcard with Sennheiser 650s. There's quite a marked difference IMO. The Streamliner is much fuller.

[quote name='gjones' timestamp='1504959019' post='3368562'] Just before the second set I had another look at the amp and realised that I was plugged into channel 1 and I had been adjusting my sound with the EQ of channel 2. I could have sworn I was hearing the sound change when I was adding more bass and reducing the treble but in reality, it was all a figment of my imagination. [/quote] Been there, done that. It's a really important lesson.

Now that I’ve gigged the prototype, I’m ready to assemble a finished cabinet in our cabinet material of choice, 15mm poplar ply. Although I am now using different drivers to the ones we started out with, this doesn’t affect the construction of the cabinet. The bracing is slightly different, due to the fact that we want to get two cabs out of a single piece of plywood. However, the lessons learned in building the prototype will be applied here. First, cut the figure-8 brace and glue in place on the back panel. I used a couple of screws to clamp it down, but my plan is to assemble the whole box without any (external) screws. Filling and sanding these can be a real pain. To assemble without screws will require some longish clamps, which I ordered from eBay. If you don’t want to invest in the clamps, there’s nothing wrong with using screws, but you’ll have to fill and sand the holes later. The first problem I hit was that, despite my best efforts to drill the holes at right angles, the screws pulled the brace slightly off target. When I wiped the excess glue away, I noticed that there was a slight gap at one side. I quickly grabbed a couple of clamps to straighten it up. Phew!

Bought a very nice Behringer preamp from Chris. All good.

Way to go Geoff and Richard! Have you now modified your Ashdown cab?

Don't you hate it when that happens? I've had to dump several Canon printers over the past few years with simple faults that can't be repaired. Great when they're working, but not so great for the environment.

Splitting the crossover in two has a number of benefits. It makes the layout easier to design; it's simpler to assemble; it puts distance between the LF and HF coils, and gives you more flexibility when deciding where to locate them inside the cabinet. As far as weight saving is concerned, the crossover for the version Richard is making is about half a kg lighter than the more complex compression driver version (because of the size and number of LF inductors). You could also save nearly a kg by using the neo version of the tweeter or the neo version of the compression driver, although that would likely require some modification to the crossover. You could save about 2kg by using a neo driver like the Faital Pro PR300 used in the Bergantino CN112 and Vanderkley 112EXT, or an Eminence Deltalight, although neither of those will go as loud as the Beyma and they would add another £50 or so to the cost. By going neo, I reckon a version with a tweeter could come in at under 12kg.

It's not as difficult as winding your own pickups, and certainly feasible for the adept DIY'er, but you'd have to invest in the wire and an inductance bridge at the very least. So it's probably not worth it if you're only making a few.

Using cardboard as a template is a great idea. The standoff strips are another good idea, allowing for some free space below the board for the wiring and tie wraps.

I'm looking forward to seeing how it works out.

That's a bit of a long wait, Richard.