Plastic ducting

m4ccam

Active Member
Hello
I have been reading this part of the forum with great interest.
For the last couple of weeks I have been thinking of building a sub of my own. I was working on a job today and I happened to notice lots of different size tubes outside the factory opposite, to cut a long story short the forman gave me a length of tube that measures 2 metres long by 440mm the plastic is 5mm thick. Would this make a decent sub.
If it will I will no doubt have lots more questions.

Andy
 

Member 639844

Former Advertiser
Its free, what have you got to lose by trying?

It will work as a sub cabinet just fine, but the acoustic properties of plastic have never been considered excellent. By the same token, I dont know of anyone that has ever tried, and it could work very well.

Best way forward, try it and see. Worst case scenario is that you have the components for a sub, but the enclosure doesnt work, and you have to by some MDF or source a tube from different material.
 

m4ccam

Active Member
Ok! So the next step.
I have downloaded winisd and don't have a clue where to start and don't really know what drivers to look for. Will a 15" fit, I ask this in case the plastic is no good and I have to make a cab for it. I would like it to be around 1200mm high plus a bit for the base would be ok I will be using it for movies 95% of the time. I would be using a Behringer amp as I would like to add a transducer at some point.
I have an MJ reference 1 mkIII at moment. I see they get mixed reviews, I think it sounds pretty good but I want more spl.
If I put say 500 quid into a project would that be enough to get a decent quality sub.
 

swiftpete

Distinguished Member
Sonosub - Free Speaker Design Software

Use this to model your cylinder sub, it's very easy to use. FYI, the cylinder sub I'm about to start building is similar in dimensions to yours, check out my thread for more info.
15 inch won't fit according to sonosub, but you'll get a 12 in there. 287 litre cabinet, 12.5cm diameter port 52cm long gives you a tune of 14.5hz.
 
Last edited:

Nimby

Distinguished Member
Plastic is quite an acoustically dead material so it may be better than other materials for a cylinder sub. It also has a nice surface finish. 5mm is quite a good thickness without it becoming too heavy to handle. Keep it out of the sun as it may degrade under UV bombardment. Don't treat it like steel because it will crack if you stretch its flexible properties too far. Pretending it is a rigid material is safest.

You will need to cut some accurate ring baffles in MDF or plywood to reinforce it. Best tool for this is a router with a radius bar to ensure smooth, accurately round circles to the correct dimensions. Don't force the rings into the PVC tube or it may crack. Have fun. :)
 

Member 639844

Former Advertiser
i wouldnt right off a 15inch driver just yet, for example, a single sealed av15 driver only needs 90 to 120 litres. With the best part of 250 to work with, its not of the cards should a large driver attract you.
 

swiftpete

Distinguished Member
Well it's just the physical space needed to fit it in. There is very little clearance either side with 440mm diameter tubing.
 
Just build a 500mm by 500mm by 200mm MDF box (for the driver) to mount to the bottom of the tube and you could build one for the top too if needed, then you could call it the "tower of bass":laugh:.

You could cut the tube in half and do dual subs with a volume of around 5-6 cubic feet per sub (including the box mount and stuffing).:smashin:
 

m4ccam

Active Member
This is all sounding quite good. Swiftpete It was your project that intrigued me.
When I told the guy what I wanted it for he said draw a picture of what I wanted and they would cut it to size and if it needed a top and feet they would make it all out of plastic and weld it all together FOC.
The 15" driver was just in case it's no good and I need to build a box.
Homeboy. I do like the sound of that but I think two would be pushing it a bit, I told the wife about Swiftpete's and her reply was "and he's still married" then she walked out into the garden and looked at my tube.
I have all the tools that I should need so there is no probs there.

Thanks for the thoughts so far.
 

m4ccam

Active Member
I like the sound of the Tower of Bass. I can aquire an 18mm sheet of ply from the job I am on. Is ply any good if I double the thickness and glue and screw it together. or am I better buying a sheet of 25mm mdf?
Swiftpete thanks for the link. I think I will be able to get my head around that but if I build a TOB, as Homeboy mentioned I think I will need lots of help from all the experienced sub builders if you all don't mind.
 
18mm ply is fine, lots of people use it for their builds in the US, it is much lighter then MDF, but is said to be stiffer, depending on the grade. A double baffle for the driver would be good and the rest 18mm, with a few braces would do the trick.

Have you definitely decided on building just the one sub then?
 
The shiva X2 12" and the tempest X2 15" are a couple of subs worth looking into, they cost €255 and €275 each, and are available from What's New Here.

The shiva is perfect for 5 cubic feet ported, and the tempest looks good sealed or ported at that volume.
 

m4ccam

Active Member
I think I would be pushing a little too far building two. When err indoors saw the 2m tube in the garden she was none too happy. I have told her I will sell the reference 1 when I have built one.
If the first one turns out looking good and not too inposing I may be able to sweet talk her into having two.
The fella I spoke to said they had all sorts of sizes and I was welcome to more if I wanted FoC.
I Think the best way forward is to assume just having one.
 

swiftpete

Distinguished Member
For some reason women are never too impressed when it comes to enormous subwoofers. My OH tuts whenever I buy any new av stuff and moaned when I blacked out the room for projector etc. But she now has film nights where her mates come over with popcorn and they love it.
I'm getting a right load of grief over the new sub as it's going to be big and as she keeps telling me over and over again 'you don't need it'. I then tell her that I know I don't need it, but I'm upgrading what we currently have. 'But you don't need it'.
I've tried telling her that for roughly what I'll sell my current sub for (maybe I've tinkered with the figures slightly here) I'll be able to make something that outperforms what we currently have and hopefully outperforms far more expensive subs.
'But you don't need it'.
I'm going to just have to build it anyway.
 

m4ccam

Active Member
For some reason women are never too impressed when it comes to enormous subwoofers. My OH tuts whenever I buy any new av stuff and moaned when I blacked out the room for projector etc. But she now has film nights where her mates come over with popcorn and they love it.
I'm getting a right load of grief over the new sub as it's going to be big and as she keeps telling me over and over again 'you don't need it'. I then tell her that I know I don't need it, but I'm upgrading what we currently have. 'But you don't need it'.
I've tried telling her that for roughly what I'll sell my current sub for (maybe I've tinkered with the figures slightly here) I'll be able to make something that outperforms what we currently have and hopefully outperforms far more expensive subs.
'But you don't need it'.
I'm going to just have to build it anyway.

That all sounds very familiar.
I got into powerkiting about three or so years ago and ended up with a set of racekites that were a pig to fly, then I upgraded the buggy to a full blown race buggy that I "didn't really need" but now being in my mid forties and getting lifted god knows how high and flipping the thing a couple of times at 40 odd mph I don't bounce so well anymore so I sold up a few months back and bought a 50" g20 (as the old crt was on it's way out. cough) and a blu ray player.
I have now got the av bug again so last week I bought a projector which the wife would not entertain but when she saw the picture she even commented on how good it was.
Then when I found this thread I saw your post and found it very interesting. I have been waiting for your updates on it.
I should have the plywood tomorrow so all being well I can start making the box at the weekend.
 

swiftpete

Distinguished Member
I also got into powerkiting a couple of years ago. Still fly, but never got into buggying, just jumping. I've got a 4.9 blade at the moment, thinking at some point of getting something bigger.

I will be updating, just got to wait for all the different bits and bobs to arrive from different sellers before I can get stuck in. Main thing being the router, as I can't even get started without that really. I'm hoping, if everything arrives, to start this weekend.
 

m4ccam

Active Member
Carefull with that blade.
A few years ago I bought a triton 2000 saw table and router table from a joiner I was working with, I had all the good intentions of building a garden bench and other stuff, it never happened.
I bought a router, circular saw, jig saw, and quite a lot of other stuff thats in a big steel box in the shed where it has been for the last couple of years.

Good luck with the build.
 

m4ccam

Active Member
I am now having a rethink about building this sub with a 15" driver.
I have had the MJ for a few years and never really felt it was big enough, however after reading these forums I decided to have a mess about with it. I moved it in to where the front speaker was and the speaker to where the sub was, I also had a mess around with the phase and set it to 20 instead of zero as I was told to. This has made a huge difference, I actually hear and feel it now. I started to increase the volume and ended up with the light fittings rattling amongst other things.
I want to build a cylinder sub as I like the look of them but I'm a bit concerned about using a large driver.
Could someone give me some thoughts as to what to do.

Cheers Andy
 

The latest video from AVForums

Podcast: Reported HDMI 2.1 bugs, Audiolab Amp & LG LED Projector reviews + Best of the Month
Top Bottom