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Discussion Starter · #1 ·
Just thought I'd share with you lot some images of my finished DIY subwoofer and my overall system.


I bought the basic hexagonal box and driver from eBay and spent a couple of weekends getting rid of the imperfections in the woodwork, sealing every last gap in the wood, and painting it.

The driver is a 12" car driver and is in excellent overall condition. This whole thing cost me about £30.


About a week later I decided to add a port, so went and bought some drainpipe, calculated the port length and drilled the hole. I could immediately notice much less distortion, far deeper bass and less excursion to reach deeper levels.


I'm extremely happy with this. Instead of spending loads of hard earned money on a manufactured sub, I spent around £30 and have one that sounds very close! It integrates with the rest of my system superbly and generally sounds fantastic. Those terribly overblown light-sabre sound effects in SW Episode 2 give it a good work out! :eek:


So there you have it. Questions or comments? Don't hesitate to ask/mention.



Pics of the sub:

Here
And here


Pics of my system:

Here
 

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Howard-Canning,


Nice looking sub and system. I have been considering building a sub for future HT and have been digging aroung lately. Yours is the first hexagon design I have seen, and I like it. I was considering a sonotube but now I wonder...


What made you decide to go with a hex design? Are there performance advantages with a hex over boxes and tubes? Or is it just personal preference? (I know all "sound" is subjective) But in terms of pure design considerations, where does the hex fit in?


Once again nice sub, nothing like satisfaction from a job well done.


Jerry
 

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Discussion Starter · #3 ·
TBH I have no idea why it's a hexagon - I bought it pre-built from eBay and unfinished, I didn't build the basic box. Some say it reduces standing waves by diffusing them or something. But I think it just looks better than a standard box.


I'd say go for a hexagonal design if you're going to build one - too many people have standard cube/cuboids and SonoTubes ;)



Anyway I had to put some more of the 2Metres of drainpipe I bought for the port to use, so I made some feet out of 3Inch long tubes of pipe, and now the sub sounds even better in downfiring mode.


So I am currently waiting for the spraypaint to dry after painting the "feet" silver (gotta add some element of style!)



I also need to paint the now top of the sub (the bottom we didn't bother painting black originally cos you couldn't see it) so that'll be done next weekend.


Pics so far:

http://homepage.ntlworld.com/tony.canning/subfeet1.jpg

http://homepage.ntlworld.com/tony.canning/subfeet2.jpg

http://homepage.ntlworld.com/tony.canning/subfeet3.jpg
 

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A quick search for hexagon subwoofers did not turn up much. A high end JBl sub, some German sites (can't read German), and a hexagon shaped subwoofer, interesting. It would be nice to build something different, what did you use to calculate the port size/length? Is it tuned to a specific freq? The legs add something to be sure.


Jerry
 

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Discussion Starter · #5 ·
The legs aren't ports.

I used WinISD I think, with the advice of someone on some forums, based on the width of the drainpipe.
 

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"The legs aren't ports"


I didn't think say or think they were....
 

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Discussion Starter · #7 ·
Sorry I thought when you said "The legs add something for sure" you meant sound-wise :blush:
 

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No problem :) when i try to think and write without a good edit I can be confusing.....


does it sound different down firing as opposed to front firing?


any experts out there care to comment on hexagon subs?


I am intrigued by the design


jerry
 

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Discussion Starter · #9 ·
Yeah it sounds a lot different, and better.

Enhances the real low end more, and you can feel it a lot more too :D
 

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Discussion Starter · #11 ·
A Yamaha NSC120
 

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supposedly it will stop standing waves but if you have good internal bracing half way down and an angle on one of the faces it will also do the same thing. port lengths are calculated by finding the q of the speaker and trying to match that sweet spot freq or one can tweak the freq they would like. some even put in two different lengths to try to balance a speaker. its been so long since i actually built a box for car audio i bought a book fro ratshack called speaker builders handbook. will teach you the difference between the different types of box from first order to 9th order..
 

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Howard, when you bought the driver and enclosure, did you get any of the T/S parameters for the driver? What is the resonant frequency, the Q of the driver? I am wondering how you came up with port length for the driver if you don't have any of this info. If all that came with the driver, then great. The only thing I would be worried about is that your subwoofer is only acting as a woofer since it is not reaching the "sub" levels. The reason I say this is because most car audio subs are not meant to go as low, since they take advantage of the "cabin gain" that you get from putting the driver in a small room, otherwise known as a car.


There is a lot that goes into building a sub and taking a sealed box and just cutting a hole in it and shoving some drain pipe in for a port is not the way most people do it. I don't want to sound crass, and I don't mean to belittle you or anything like that, so please don't take this as a personal slam, I just want others to know how it should normally be done. There are books on the subject, such as Vance Dickason's book "The loudspeaker design cookbook" that goes into much detail on figuring all this out. It can be bought through Amazon or AudioXpress.
 

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Quote:
Originally posted by Spydrman
What made you decide to go with a hex design? Are there performance advantages with a hex over boxes and tubes? Or is it just personal preference? (I know all "sound" is subjective) But in terms of pure design considerations, where does the hex fit in?
A hexagon makes perfect sense. It's a "maximum beveled cube or rectangle box".


"What is the best shape for the box? Internal reflections in the box combined with the vibration of the box itself can cause spikes in the frequency response of the system. Different box shapes have a different effect, with perfect cubes being the worst and spherical or egg shaped boxes being the best. Although spheres have advantages, it is very difficult to create a spherical speaker box that is as strong as a typical rectangular box." Quoted from this site - http://lalena.com/audio/faq/speaker/


Shape Variation

Cube +-5.0 db

Rectangle +-3.0 db

Cylinder +-2.0 db

Beveled Cube +-1.5 db

Beveled Rectangle +-1.5 db

Sphere +-0.5 db


I hear box dimension ratios are not important for a sub - http://www.diysubwoofers.org/faq.htm Then again I'm scratching my head as Bigus at this thread - http://www.avsforum.com/avs-vb/showt...5&pagenumber=6 - says a cube or sphere are the worst shapes for standing waves in the sub (but the sphere would be great for higher frequencies like mid or hi range...).


Norh says it also doesn't matter "Parallel surfaces is not an issue for subwoofers" - http://www.norh.com/about/tech/ Note there are also Prism shapes which would be possibly an even better "beveled" shape (from a cube or rectangle). Interesting stuff about the "ultimate" speaker shapes...
 

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Discussion Starter · #15 ·
Quote:
Originally posted by SVonhof
Howard, when you bought the driver and enclosure, did you get any of the T/S parameters for the driver? What is the resonant frequency, the Q of the driver? I am wondering how you came up with port length for the driver if you don't have any of this info. If all that came with the driver, then great. The only thing I would be worried about is that your subwoofer is only acting as a woofer since it is not reaching the "sub" levels. The reason I say this is because most car audio subs are not meant to go as low, since they take advantage of the "cabin gain" that you get from putting the driver in a small room, otherwise known as a car.


There is a lot that goes into building a sub and taking a sealed box and just cutting a hole in it and shoving some drain pipe in for a port is not the way most people do it. I don't want to sound crass, and I don't mean to belittle you or anything like that, so please don't take this as a personal slam, I just want others to know how it should normally be done. There are books on the subject, such as Vance Dickason's book "The loudspeaker design cookbook" that goes into much detail on figuring all this out. It can be bought through Amazon or AudioXpress.
This is all very well for people who are willing to spend hundreds of pounds/dollars on it, but I am unable to spend that sort of money on, or building a subwoofer.


And if you read my initial post you'll see that I didn't make the box, choose the driver or anything. I bought it fairly pre-made from eBay.


Sure, it won't sound as good as the DIY efforts people invest hundreds in, but IMHO it sounds really good for what it is.

I used the help of some people on another forum and various aspects of the box, tuning frequency (I did it a bit higher seeing as it's a car driver, abougt 30Hz), etc to calculate the port length. So it's not all just a "bodged" job.


I'm not being rude, but if you had read the initial post there might not have been any need for some of the above post.

And yes I did feel belittled.




Howard
 

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I am sorry for any bad feelings you got from my post. The only thing I was trying to do was explain to others (who may be willing to spend more on their design) what to take into consideration when building a sub. All told, the calculations are pretty easy, the building is harder and if you do a ported sub and want to tweak it for the best possible performance, is the most time consuming. Vance Dickason even goes as far as to reccomend building a dummy box for the driver you are using so that you can play with all the dimensions to tune everything. The other thing is that for those that have more time than money available and have the skills and tools for making their boxes, if they are willing to do some extensive research on the web and reading books, they can choose some in-expensive drivers that do a great job. MDF doesn't cost much and you can make lost of trial boxes if you have the time. None of them have to look as nice as your cabinet either.


I did read the first post, so I did understand why you bought it all from the beginning. I am glad you are happy with what you have, that is part of life. To defend you, I have seen some very in-expensive cabinets paired with in-expensive drivers that sounded very good.


I will shut up now, unless somebody specifically asks me to reply to something.
 

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Quote:
Originally posted by SVonhof
I am sorry for any bad feelings you got from my post. The only thing I was trying to do was explain to others (who may be willing to spend more on their design) what to take into consideration when building a sub. All told, the calculations are pretty easy, the building is harder and if you do a ported sub and want to tweak it for the best possible performance, is the most time consuming. Vance Dickason even goes as far as to reccomend building a dummy box for the driver you are using so that you can play with all the dimensions to tune everything. The other thing is that for those that have more time than money available and have the skills and tools for making their boxes, if they are willing to do some extensive research on the web and reading books, they can choose some in-expensive drivers that do a great job. MDF doesn't cost much and you can make lost of trial boxes if you have the time. None of them have to look as nice as your cabinet either.


I did read the first post, so I did understand why you bought it all from the beginning. I am glad you are happy with what you have, that is part of life. To defend you, I have seen some very in-expensive cabinets paired with in-expensive drivers that sounded very good.


I will shut up now, unless somebody specifically asks me to reply to something.


I'm not really sure why he took offense to your post either. You were just trying to be educational and informative to others that would obviously be reading this thread. On that note, yes, one can build a really decent sub for next to nothing using Vance's excellent cookbook series, or winisd (I still use that program - it's excellent) to plot out box options for various drivers. I've designed countless boxes for people using drivers that cost next to nothing that have performed waaayyyyyy beyond the owners' expectations for pennies on the $$. Probably my cheapest high performer was a tiny 4th order, isobarik bandpass box using four 8 inch, 16ohm drivers that cost $3.65 ea, on clearance from MCM. 2 friends of mine needed subs - one for car, the other for home, and they both got a set of these drivers. The car one was the example above, while the home version was an isobarik vented design for a deeper rolloff and more efficiency. The car sub (with cabin gain) easily dipped into the high 20's, while the home version rolled off at about 24Hz. Bass quality was smooth, fast and tight. Each box, including materials was a whopping $30, before finish. The guy who did the car sub spent more on the carpet to go over the wood than he did on the whole box! As you can see, truly awsome values can be achieved with "knowledge". I think your post deserved notice... ;)
 

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I followed your links to see your sub. Nice job! I built my first home sub a couple of months ago also using a JL Audio driver. I used the 12W6 and a parts express 250W plate amp. I experimented a little with a ported 2.25 cu.ft. enclosure, but ended up going with a 1.5 cu.ft. sealed enclosure.


I didn't use any design software, but rather enclosure designs from JL Audio. They had 3 sealed, 3 ported, and 1 bandpass design all using the 12W6. This info. was on their website, but I haven't been able to find it lately. (good thing I printed all of the designs a year or so ago)


I will take some pics of my sub when I finish it. (It's currently unfinished MDF)


Could you recommend some speaker design software (preferably freeware) that a novice could understand. I am hoping to DIY some main and center speakers in a couple of months.
 

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Unibox is about the best freeware and highly recommended - http://www.danbbs.dk/~ko/ubtxt.htm There's also WinISD.


Other great loudspeaker design software:


True Audio WinSpeakerz $129.00

True Audio TrueRTA Level 4 $99.95

True Audio 'Introduction to Loudspeaker Design" by John L Murphy $24.95

SoundEasy V8.0, EasyLab, BoxCad $225.00

LspCAD, justMLS $129.00

LspCAD PRO, justMLS $495.00

PureBits Sample Champion Light $113.56

PureBits Sample Champion Pro $342.99

PureBits Sample Champion - Impedance and Thiele Small Plugin $33.27

PureBits Sample Champion Pro + all Plugins Bundle

SpectraPLUS 3.32

SpectraPRO 3.32

SpectraLAB 4.32

HobbyBox V.5

CLIOWin Lite with PCI card, signal Conditioner, and Mitey Mike II $749.00

LoudSpeaker LAB 2 with measurement box $310.00

LoudSpeaker LAB 2 with measurement box including a calibrated microphone $400.00

Liberty Instruments - Praxis, AudPod measurements, Girardin mic

LinearX Systems LMS - Loudspeaker Measurement System $1,395.00

LinearX Systems Leap5 enclosure and crossover design modules $1,490.00


Personally, I like SoundEasy, which also includes EasyLab and BoxCad. It covers just about EVERYTHING you can dream of... :D
 

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Thanks METANIUM, but remember that I miscalculated and had to make due with improper dims and calcs. I should actually re-do the cabinet, since I don't have the same space requirements that I used to. I can now handle a larger box and can get the proper size for the driver. It doesn't sound bad, but it helps that it is in a corner and the corner is also in an alcove. It enhances the bass. I just know that if my wife sees me making a new cabinet for it, she will wonder why. I will explain and she won't understand, since it sounds fine the way it is. I guess it looks better than it sounds, even though it suits us fine for the sound too.
 
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