alexclaber Posted February 12, 2008 Share Posted February 12, 2008 (edited) Finally bitten the bullet and ordered the parts for this cab. Basically it's an Eminence 3015LF woofer in a ~110 litre ported box tuned to 46Hz with a sealed sub-enclosure containing an Eighteen Sound 6ND410 midrange. Am still hunting down some suitable plywood - looking for high quality 9mm baltic birch with equal thickness plies throughout. Will be doing all manner of strange bracing to get sufficient stiffness from such thin ply. External dimensions will be ~ 32" high x 20" wide x 16.5" deep - a neat fit in the boot of my car along with my 4U shallow rack. Estimated weight <50lbs. Alex Edited July 28, 2008 by alexclaber Link to comment Share on other sites More sharing options...
Merton Posted February 12, 2008 Share Posted February 12, 2008 Cool, looking forward to watching this develop, you've been talking about it for a while! Link to comment Share on other sites More sharing options...
bremen Posted February 12, 2008 Share Posted February 12, 2008 [quote name='alexclaber' post='138833' date='Feb 12 2008, 01:30 PM']Finally bitten the bullet and ordered the parts for this cab. Basically it's an Eminence 3015LF woofer in a ~110 litre ported box tuned to 46Hz with a sealed sub-enclosure containing an Eighteen Sound 6ND410 midrange. Am still hunting down some suitable plywood - looking for high quality 9mm baltic birch with equal thickness plies throughout. Will be doing all manner of strange bracing to get sufficient stiffness from such thin ply. External dimensions will be ~ 32" high x 20" wide x 16.5" deep - a neat fit in the boot of my car along with my 4U shallow rack. Estimated weight <50lbs. Alex[/quote] I braced my cabinets with 'shelves' of 9mm ply full of 2" holes; one of these 'shelves' connects the back of the magnet (via blu-tak) to the rear of the cabinet. I nicked that idea from Tannoy. What else will you do? 9mm is pretty bold, but for sure a well-braced 9mm cabinet will be better than an 18mm poorly braced one. Hope it goes well! by the way, top tip for ports: Screwfix sell 100mm diameter poly pipe in 200mm (iirc) lengths, designed for tumble dryer outlets. It's a good interference fit in a hole drilled with a Screwfix 2" holesaw. Link to comment Share on other sites More sharing options...
alexclaber Posted February 12, 2008 Author Share Posted February 12, 2008 [quote name='Merton' post='138879' date='Feb 12 2008, 02:37 PM']Cool, looking forward to watching this develop, you've been talking about it for a while![/quote] Yeah, I've been through so many different designs so I wanted to make sure I didn't think of anything better before I committed to the build! [quote name='bremen' post='138884' date='Feb 12 2008, 02:39 PM']What else will you do? 9mm is pretty bold, but for sure a well-braced 9mm cabinet will be better than an 18mm poorly braced one. Hope it goes well![/quote] I'm going to divide all the panels with strips of ply set at right angles but before glueing them in I'm going to prestress the cab with 2"x2" and wedges so the panels and bracing are tensioning each other. The port is going to be a large triangular port which will brace part of the cab and the mid enclosure is going to be a wedge shape that braces another part. All the joints will be butt joints with 18x18mm wood running along the inside edges to increase the glued surface and add further strength. I'm quite new to woodwork so need to keep it relatively simple, though longwinded... Alex Link to comment Share on other sites More sharing options...
alexclaber Posted February 13, 2008 Author Share Posted February 13, 2008 A box of fun containing connectors, leads, grill cloth and the most spectacularly light 15" woofer I have ever held, has arrived! Honestly, I thought the box was empty before I saw all 15" of bass awesomeness staring back at me... Alex Link to comment Share on other sites More sharing options...
Dood Posted February 13, 2008 Share Posted February 13, 2008 Alex, I look forward to seeing this build come along. I know that you had done a fair amount of research with your box sizing and response charts. I'm sure I speak for a few of us when I see that we'd love to see your findings, as it made interesting reading before. I'm already interested in seeing how a non biamped version would work out. Another interesting find: Powersoft, (I own one of their poweramps) I see actually make 2 way biamp modules that can be added to a cabinet to make it active too! The treble and bass signals are treated actively (as opposed to just having a single amp and passive crossover.) Whats the projected costs involved Alex? Link to comment Share on other sites More sharing options...
alexclaber Posted February 13, 2008 Author Share Posted February 13, 2008 [quote name='dood' post='139595' date='Feb 13 2008, 03:55 PM']I'm already interested in seeing how a non biamped version would work out.[/quote] Me too, think it would be a very nice match with one of the higher power lightweight heads on the market. I'm actually intending to use a passive line level crossover, which will be a split lead with a small box in the middle, so if you have two amp channels you can put this between preamp and power amp and you get a 2nd order highpass and 1st order lowpass, with sufficient attentuation on the highpass to match the sensitivities. [quote name='dood' post='139595' date='Feb 13 2008, 03:55 PM']Another interesting find: Powersoft, (I own one of their poweramps) I see actually make 2 way biamp modules that can be added to a cabinet to make it active too! The treble and bass signals are treated actively (as opposed to just having a single amp and passive crossover.)[/quote] There's quite a lot of active modules on the market - unfortunately they all cost rather a lot - and I already own a very nice power amp. [quote name='dood' post='139595' date='Feb 13 2008, 03:55 PM']Whats the projected costs involved Alex?[/quote] This is where it gets challenging. Things to bear in mind with cab building: 1. Good plywood is quite expensive. 2. Crossover components are expensive. 3. Metal grills are expensive - and heavy! 4. Casters, handles and corners are expensive - and potentially heavy. 5. Finishing - paint/carpet/tolex - none is easy to do well, all cost money. So in light of all that I've decided to go for very thin birch ply - cheaper and lighter but requires much more bracing - plastic handles, no corners, no casters, paint finish, fabric grill and the aforementioned biamping with PLLXO. The 3015LF is great value, about £100. The midrange is certainly good value because it is incredibly high output and low distortion, sufficiently so to keep up with a pair of 15"s being hit by high wattage - unfortunately it is rather expensive and actually costs more than the woofer! Other components have been pretty cheap. I'm enjoying the challenge of trying to build the best possible cab for as little money as possible - much more fun than just throwing money at it. Alex Link to comment Share on other sites More sharing options...
RIM Basses Posted February 13, 2008 Share Posted February 13, 2008 Go on Alex! you are the tech head of bass feq! Link to comment Share on other sites More sharing options...
mhuk Posted February 13, 2008 Share Posted February 13, 2008 [quote]4. Casters, handles and corners are expensive - and potentially heavy.[/quote] You must be buying from a different supplier - from Blue Aran handles (medium=450g, large=575g) are about £4 and corners 50p (25g). Not sure about casters as I didn't buy any. Link to comment Share on other sites More sharing options...
alexclaber Posted February 13, 2008 Author Share Posted February 13, 2008 [quote name='mhuk' post='139777' date='Feb 13 2008, 06:45 PM']You must be buying from a different supplier - from Blue Aran handles (medium=450g, large=575g) are about £4 and corners 50p (25g).[/quote] I should have said casters and handles can be expensive and heavy - the large diameter casters and steel handles weigh a ton. But yes, I did get the lightweight cheap plastic handles from Blue Aran! Alex Link to comment Share on other sites More sharing options...
alexclaber Posted February 14, 2008 Author Share Posted February 14, 2008 Apparently the midrange speaker will be with me next week (all the way from lautsprecher shop - you can guess where that is...) Have also ordered the parts for the PLLXO from Maplins - the main cost of that was actually the XLR plugs and sockets - the capacitors and resistors cost about £3! Alex Link to comment Share on other sites More sharing options...
alexclaber Posted February 15, 2008 Author Share Posted February 15, 2008 Well that was quick! The stuff from Maplin arrived today - all correct apart from the bizarre substitution of one of the lengths of coloured bell wire by bell wire fixings... Alex Link to comment Share on other sites More sharing options...
david_l_perry Posted February 22, 2008 Share Posted February 22, 2008 (edited) Alex, just found this thread. What are you building, do you have another thread with the details ? Very interested in what you are proposing. 9mm should be spot on with adequate internal bracing Edit just spotted the dims and tuning.... Its pretty large (6x10 size !!), I assumed it was going to be a tiny little AGUILAR type cab....but then the driver does benefit from internal volume to get the external volume.... Dave Edited February 22, 2008 by david_l_perry Link to comment Share on other sites More sharing options...
alexclaber Posted February 22, 2008 Author Share Posted February 22, 2008 [quote name='david_l_perry' post='144845' date='Feb 22 2008, 09:40 AM']Its pretty large (6x10 size !!), I assumed it was going to be a tiny little AGUILAR type cab....but then the driver does benefit from internal volume to get the external volume....[/quote] It's more like 4x10" size than 6x10", so not quite as huge as say an Omni 15. But as you say, if you want decent response from a woofer you need to give it enough space, and if you do so then you can also fit in a nice big (and thus low air velocity and thus lower distortion/compression) port. Despite the height, it's quite narrow and shallow so hopefully won't be too much of a pain with doorways and staircases... Alex Link to comment Share on other sites More sharing options...
Dood Posted February 22, 2008 Share Posted February 22, 2008 Knowing that you have a good knowledge of winisd (and I dont have a copy nearby to check) are the dimensions set in stone for best response / least distortion etc? for example, would it hurt lopping off height and adding it to depth instead? not related to your build diary, whilst I have been potentially looking at getting a single 1x12 type cab, I did start wondering about the acme method of getting cabs to go low. It'd be interesting to see a 1x12 + mid + tweeter in a smaller box. I'd expect the same sensitivity as the acme 2x10's, but would be nice to find out how LOW a cab of that type could go. Link to comment Share on other sites More sharing options...
bremen Posted February 22, 2008 Share Posted February 22, 2008 [quote name='dood' post='144950' date='Feb 22 2008, 12:17 PM']Knowing that you have a good knowledge of winisd (and I dont have a copy nearby to check) are the dimensions set in stone for best response / least distortion etc? for example, would it hurt lopping off height and adding it to depth instead?[/quote] Cabinet shape (within reasonable limits) makes no difference to bass response or distortion. For high mid frequencies you do have to consider ratios so you don't end up with one big fat standing wave (eg a cube), but using bracing as Alex intends will help break these up anyway. Link to comment Share on other sites More sharing options...
alexclaber Posted February 22, 2008 Author Share Posted February 22, 2008 [quote name='bremen' post='144959' date='Feb 22 2008, 12:28 PM']Cabinet shape (within reasonable limits) makes no difference to bass response or distortion. For high mid frequencies you do have to consider ratios so you don't end up with one big fat standing wave (eg a cube), but using bracing as Alex intends will help break these up anyway.[/quote] Indeed. Two things I'm doing to minimise standing wave issues is using a triangular port which will turn the cab interior into a pentagonal prism fused with a cuboid, hence few equal distances between boundaries; and also also placing the midrange in an irregular square based pyramid further breaking up the shape of the woofer enclosure and acting like the tapered B&W nautilus enclosures from the mid's perspective. [quote name='dood' post='144950' date='Feb 22 2008, 12:17 PM']not related to your build diary, whilst I have been potentially looking at getting a single 1x12 type cab, I did start wondering about the acme method of getting cabs to go low. It'd be interesting to see a 1x12 + mid + tweeter in a smaller box. I'd expect the same sensitivity as the acme 2x10's, but would be nice to find out how LOW a cab of that type could go.[/quote] Unfortunately there are no 12" woofers on the market that can do what two Acme 10"s do in the same or less volume - I should know, I've searched pretty extensively! I gather there may be a Kappalite 3012LF in the pipeline which will hopefully have the kind of Xmax you want but is still unlikely to have a low enough Fs or Vas to do the Acme thang. If I could persuade myself to spend the money on a nice compact head, like an AI Clarus/Focus, then I'd definitely get a Low-B1 as a micro/practice rig - fantastic little cab! Alex Link to comment Share on other sites More sharing options...
alexclaber Posted February 22, 2008 Author Share Posted February 22, 2008 Have plywood (9mm brazilian 5 ply), wood, glue (PU expanding) and screws. Had the plywood cut into four, thus saving me a few cuts and allowing me to get it into the car! Alex Link to comment Share on other sites More sharing options...
alexclaber Posted February 22, 2008 Author Share Posted February 22, 2008 I now have six plywood rectangles to form the main body of the cab. That was quite painless! Alex Link to comment Share on other sites More sharing options...
alexclaber Posted February 23, 2008 Author Share Posted February 23, 2008 Have built 5 sides of the box, put it in the boot of my car and found that I can't fit the rack through the opening even though it would theoretically fit once it's in. Doh! Need to knock ~2" off the height. Also now that I have some experience in dealing with the joints I might go without the 3/4" runners along each joint and just be more precise with the screwing and more liberal with the glueing. Alex Link to comment Share on other sites More sharing options...
alexclaber Posted February 23, 2008 Author Share Posted February 23, 2008 I should add that the 9mm ply makes for a crazily light cab! (Unsurprisingly half the weight of the usual 18mm stuff). Alex Link to comment Share on other sites More sharing options...
Chopthebass Posted February 23, 2008 Share Posted February 23, 2008 [quote name='alexclaber' post='145589' date='Feb 23 2008, 01:50 PM']Have built 5 sides of the box, put it in the boot of my car and found that I can't fit the rack through the opening even though it would theoretically fit once it's in. Doh! Need to knock ~2" off the height. Also now that I have some experience in dealing with the joints I might go without the 3/4" runners along each joint and just be more precise with the screwing and more liberal with the glueing. Alex[/quote] You could use biscuit joint instead of 3/4" timber runners - this will keep things aligned when clamping and save a bit of weight and avoid the need for screws. Just a thought! Link to comment Share on other sites More sharing options...
alexclaber Posted February 23, 2008 Author Share Posted February 23, 2008 [quote name='Chopthebass' post='145595' date='Feb 23 2008, 02:03 PM']You could use biscuit joint instead of 3/4" timber runners - this will keep things aligned when clamping and save a bit of weight and avoid the need for screws.[/quote] Would I not need a biscuit jointer for that? Alex Link to comment Share on other sites More sharing options...
warwickhunt Posted February 24, 2008 Share Posted February 24, 2008 Just as well you tried the skeletal cab in the boot before you'd finished it Amazing how many times you can measure something and convince yourself something should fit only to find that there is a law of physic that only applies to bassists; this particular law comes right after 'Einstein's law regarding the Invariance of the Speed of Light in a vacuum' and before the law of 'The inability to remove an object from a room or staircase even though it went in there in the first place' as written about my Douglas Adams in 'The long Dark Tea-Time of the Soul' Looking forward to the finished item. Link to comment Share on other sites More sharing options...
alexclaber Posted February 24, 2008 Author Share Posted February 24, 2008 Been doing some more thinking about the bracing and joints. Looking forward to getting iteration 2 happening. I think I need to get a big framing square so make sure all the panels are true rectangles. Now I've seen how big this is compared to my Acmes, I'm looking to build a baby cab for monitoring myself when recording (usually in my drummer's loft). Current plan is a Deltalite II 2510 in 50 litres tuned to 50Hz. Wanted a midrange speaker but I can't find anything yet that'll do the job like the 6ND410 but I'm not paying another £100 for one of them! So looking at using the Eminence APT150 supertweeter, and then making my PLLXO switchable between 750Hz (for 15/6) and 1300/2000Hz (10/tweeter) crossover points. Alex Link to comment Share on other sites More sharing options...
.gif.9ad672bb8b84505709f76b39c8c256ec.gif)
Recommended Posts