fryer Posted May 28, 2018 Author Share Posted May 28, 2018 But I have drawn the plans. First one is how it should look, with my ATS cab on top. Second is the detail, and third is the cutting list. cab design - 1.pdf cab design - 2.pdf cab design - 3.pdf Quote Link to comment Share on other sites More sharing options...
fryer Posted May 28, 2018 Author Share Posted May 28, 2018 Why haven't these pdf's appeared as pictures ? Quote Link to comment Share on other sites More sharing options...
RichardH Posted May 28, 2018 Share Posted May 28, 2018 ...because you can't display PDFs inline. You would need to put them up as JPGs. Quote Link to comment Share on other sites More sharing options...
RichardH Posted May 28, 2018 Share Posted May 28, 2018 14 hours ago, Phil Starr said: Couldn't resist it I've modelled your cab tuned to 55Hz and compared to my 30l cab It will give you just over 2dB more bass from 100hz down to 40hz (fundamental of bottom E). That extra box volume will give you noticeably more bass in other words, at the cost of a little power handling but power handling is still good, there's a dip to 300W at 90Hz and it handles 180w at bottom E which is pretty good, way better than the Eminence you started looking at. In practice you don't get a lot of fundamental from the pickups so unless you start using stupid power and an octaver you won't have problems at all in any normal use. There's still a bit of extra 'punch' at 120Hz but it's not a bad frequency response at all. Use one port of 110mm (plastic waste pipe) 15.5cm long or two 64mm (guttering downpipe) vents at 11.2 cm long. (or 3 at 19.2cm) You'll get a little wind noise at full power but you probably won't notice it in practice. Phil, out of interest I tried firing up WinISD to see the graph you get with these numbers (46l box, 55Hz tuning). To get the same port length I needed to take the box volume down to just over 40l - so I assume the 6l difference is you taking account of the driver and port volume? 1 Quote Link to comment Share on other sites More sharing options...
fryer Posted May 28, 2018 Author Share Posted May 28, 2018 ok, thanks. I'll convert them at work tomorrow. But for now I have taken a photo of them. Quote Link to comment Share on other sites More sharing options...
Phil Starr Posted May 28, 2018 Share Posted May 28, 2018 1 hour ago, RichardH said: Phil, out of interest I tried firing up WinISD to see the graph you get with these numbers (46l box, 55Hz tuning). To get the same port length I needed to take the box volume down to just over 40l - so I assume the 6l difference is you taking account of the driver and port volume? Yes that's right I assumed 40l, speaker ports and any bracing Quote Link to comment Share on other sites More sharing options...
fryer Posted May 28, 2018 Author Share Posted May 28, 2018 Insulation. The board I'm using is leftover from a friend's flooring, and has around 6 mm of pretty solid sound insulation glued to one side of it. Will this help, or should I remove it ? Quote Link to comment Share on other sites More sharing options...
fryer Posted May 28, 2018 Author Share Posted May 28, 2018 board marked and ready to saw. Maybe not as accurate as Christine Quote Link to comment Share on other sites More sharing options...
stevie Posted May 28, 2018 Share Posted May 28, 2018 It shouldn't take long with that! Quote Link to comment Share on other sites More sharing options...
stevie Posted May 28, 2018 Share Posted May 28, 2018 If there is room to fit the 110mm port, it will handle quite a lot more power than two of the smaller ones - although it looks a bit tight from here and you don't want the port right in the corner. Quote Link to comment Share on other sites More sharing options...
Phil Starr Posted May 28, 2018 Share Posted May 28, 2018 (edited) You could mount the port in the rear of the cab, that way you could fit the bigger port in. . Edited May 28, 2018 by Phil Starr Quote Link to comment Share on other sites More sharing options...
fryer Posted May 28, 2018 Author Share Posted May 28, 2018 The area of 1 x 110 ( 9.5 cm2 ) is 1 1/2 times that of 2 x 64 pipes ( 6.5 cm2 ) Is this how it handles more power ? A 110 will fit, if I move the speaker down a few mm, but it will be close to the edge - around 12 mm. Or I could put the port in the back ? Or I could use four 50 mm pipes which will fit in the front ? Quote Link to comment Share on other sites More sharing options...
stevie Posted May 28, 2018 Share Posted May 28, 2018 It's the extra area and the reduced friction from the port sides (odd though that may sound). I'd put it at the front if you can - I'm not a great fan of rear porting for bass guitar cabs. 12mm spacing from the edge should be fine. Quote Link to comment Share on other sites More sharing options...
fryer Posted May 29, 2018 Author Share Posted May 29, 2018 I've revised the plans, and now as Jpegs. Quote Link to comment Share on other sites More sharing options...
fryer Posted May 30, 2018 Author Share Posted May 30, 2018 Just a thought, but would an Eminence Kappalite 3012 LF work in this ? Quote Link to comment Share on other sites More sharing options...
fryer Posted May 31, 2018 Author Share Posted May 31, 2018 having read the '1x12 cab to replace 410' thread, I assume not. I will stick to the Beyma. Quote Link to comment Share on other sites More sharing options...
JohnDaBass Posted May 31, 2018 Share Posted May 31, 2018 +1 stick with the Beyma, you will be really pleased with it's performance. I'm a real Basschat 1X12 Mk1 Fanboy having built two slightly different designs they deliver a performance that is a match for many big brand cabs. Phil & Stevie really know their stuff and have expanded the knowledge of many who follow Basschat. Quote Link to comment Share on other sites More sharing options...
fryer Posted May 31, 2018 Author Share Posted May 31, 2018 thanks John. Quote Link to comment Share on other sites More sharing options...
fryer Posted June 1, 2018 Author Share Posted June 1, 2018 Just realised that I need to add battens in the front, to fix the grille to. I will need to squeeze the driver and the port away from the edge. Quote Link to comment Share on other sites More sharing options...
stevie Posted June 1, 2018 Share Posted June 1, 2018 If you're struggling for space, you could always put the port at the back as Phil suggested. If you decide to stick with a front port, try to get it as far from the corner as you can. Quote Link to comment Share on other sites More sharing options...
Phil Starr Posted June 2, 2018 Share Posted June 2, 2018 (edited) Yep there are arguments for and against putting the port on the back. The main argument for is that ports produce noises at mid frequencies due to all sorts of resonances, putting them round the back means the noises can't really be heard. Against is the thought that you can't ram the cab hard against a wall and potentially block the port, but even a few cm away it won't be a problem. With compact cabs it's always a bit of a problem fitting everything on the baffle without weakening the panel. The other solution might be a slot port, you'd have to form it in timber so there is extra woodwork but it's a nice tidy way of creating a port, another more complex method is that used by some manufacturers of building triangular corner ports like Mesa Edited June 2, 2018 by Phil Starr Quote Link to comment Share on other sites More sharing options...
Phil Starr Posted August 21, 2018 Share Posted August 21, 2018 any progress on this? Quote Link to comment Share on other sites More sharing options...
fleabag Posted August 21, 2018 Share Posted August 21, 2018 Maybe cut his foot off with that chainsaw ? 1 Quote Link to comment Share on other sites More sharing options...
Mottlefeeder Posted August 21, 2018 Share Posted August 21, 2018 On 02/06/2018 at 15:37, Phil Starr said: ... The other solution might be a slot port, you'd have to form it in timber so there is extra woodwork but it's a nice tidy way of creating a port, another more complex method is that used by some manufacturers of building triangular corner ports like Mesa I've seen triangular ports in some designs, but never seen any guidance about how to calculate them. Are they calculated as square ports and built in two halves, or is there some correction factor needed to compensate for the extra resistance of the additional wall, and the effect of the cab walls close by? David Quote Link to comment Share on other sites More sharing options...
Phil Starr Posted August 21, 2018 Share Posted August 21, 2018 Essentially you just need to know the cross sectional area.Add the ports together and then calculate the length. pretty much all the programs let you calculate assuming a circular port so you can just work out what diameter port would have the same area as your four triangular ports. WinISD lets you use rectangular ports which makes it even easier. Yes in theory you ought to allow for a different end correction but the change is tuning will be small. the manufacturers figures for speaker specs are rarely spot on so that's all academic. In practice you'll usually find what you have is close enough. I tend to build, check after and then if the tuning is too far out adjust the cab If it is too far out. It rarely is in practice often you are talking less than a cm of port length and a few Hz in tuning Quote Link to comment Share on other sites More sharing options...
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