| mikee55 |
Here is the place to post Tips Tricks and a vast array of knowledge about Subwoofer construction.
Please add if you see anything missing.
Mikee55 :) |
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| oshifis |
| 20 x 20 x 20 inch cube, 2 inch wall (2 layers MDF), 6th order Bandpass with passive radiator. |
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| MJL21193 |
Nice idea Mike. I have been reading this forum for a few years now and I have to giggle sometimes at some of the construction advise offered.
I am a licensed journeyman carpenter by trade, so it's fair to say that I am a reliable source.
Tools: I am spoiled, I have everything.:) With that said, you don't need much to get excellent results. If you lack tools and the skill to use them, keep your project simple.Plan your project carefully. Prepare a cut list - this will be the size of all of the sides, top and bottom of your box. Take the list to your lumberyard (Homedepot, etc.) have them cut the parts. Measure the parts before you leave to make sure they are the right size. The worst is over!
You should have some basic hand tools such as hammer, saw , drill + common size bits, screwdrivers and clamps - big ones, as in big enough to clamp acroos the box. A jigsaw in a must( maybe you could borrow one) and if you want to get fancy, a router. Routers and router bits are expensive though and strictly speaking, you can make it without it.
Screws: Save yourself some grief - don't use drywall screws. They are brittle and the head can break off while driving them. Buy the best screws you can find, usually the ones for screwing down floors are very strong. Use #8 or #10 2 inches long if you are going through 3/4 inch stock into a solid wood corner brace. Don't use too many as they may split or weaken the material you are driving them into. Do not overtighten as they may break, and always drill a pilot hole.
Glue: Glue comes in a bottle, sealant comes in a tube. Modern glue makes a joint that is actually stronger than the surrounding wood. When it comes to wood, and wood products(MDF, plywood, particle board) there are only two types of glue I will use: Yellow carpenter's glue (PVA) for all interior work, and polyurethane glue for exterior or wet applications. Both of these will form the strongest, permanent bold possible. Both of these glues work best when applied liberally to the tight fitting joint and clamped till dry. The excess will squeeze out. If you find that your joints are not tight and you lack the ability to fix it, use of the polyurethane glue will actually bridge the gap, as it foams during the drying time. It can easily fill an eight inch gap( 2 MM).
Just the basics.
Have fun
John |
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| Dr.EM |
This seems a suitable thread to ask in and should be very useful overall :) . When veneering, would you wrap the veneer around edges or must it never be folded? I'm talking about the iron on veneers such as these:
https://secure.wilmslow-audio.co.uk...4c096ad0a661887
My B&W speakers seem to have it wrapped around but it doesn't look like real wood anyhow. |
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| FastEddy |
Oh Joy! ... sub box makin' ... Got any pics?
(That glue tip from MJL21193 is a great help. The screws, too) |
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| MJL21193 |
| Dr.EM: You should veneer one face at a time. Cut your pieces slightly larger, iron on and then CAREFULLY trim off the excess. Save the face of the box for last. Patience is key. |
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| RobWells |
Dr.Em,
My old 602's were wrapped with black ash effect vinyl. Thats probably why it goes round the corners nicely - it's not veneer!
Rob. |
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| MJL21193 |
| FastEddy: Here's one. In the heat of battle, I soiled my drivers:devilr: |
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| FastEddy |
soiled my drivers ... is that like spottened your briches ?? :D
Carefully, with the shop vac set to lowest, right?
What did you end up stuffing that box with?? Or did it need any?
" ... and were very liberal with internal bracing! ..."
That's the hot tip from GR-Research.com as well = lots of bracing, corners, across the "flat lands" = the broad surface area between the corners. Check out his plans (pdf files on line). |
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| BWRX |
| I wish I had some pictures of the insides of some cabinets I saw while working at a pro audio company. They only used baltic birch plywood and were very liberal with internal bracing! I've seen some of the cabs with 2 15s take a 10 foot drop onto a stage and the damage was mainly cosmetic. |
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| MJL21193 |
| FastEddy: No stuffing. It"s lined with commercial rubber-back carpet tiles. A fairly robust enclosure weighing in at 210 pounds. |
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| FastEddy |
| Nice job ... carpet works. How thick are the walls? |
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| MJL21193 |
| FastEddy: Thanks. It's two layers of 3/4"MDF on all sides plus an outside layer of 1/2" maple veneer ply. Top and bottom have an extra layer MDF. All braces are solid maple. |
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| FastEddy |
" ... two layers of 3/4"MDF ... plus an outside layer of 1/2" maple veneer ply ..."
!! no wonder it weights 200 plus pounds !! I would bet the amp and speakers are only about 1/4 of the total.
The result is quite handsome ... keep up the good work. Canadian wood, naturally ;) |
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| MJL21193 |
No amp inside. Seperate 500++ watt amp chillin' on the rack.
The drivers have 8 pound magnets on each so that's 16 of the 210. It stays put. |
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| BWRX |
| quote: | Originally posted by MJL21193
A fairly robust enclosure weighing in at 210 pounds. |
I'll say! Are the panels laminated or screwed together (or both)? Remember to lift with your legs... or a handtruck ;) |
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| MJL21193 |
| BWRX: Both glued and screwed. |
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| BWRX |
| Very nice. Looks great by the way! |
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| MJL21193 |
More tips:
Don't use solid wood unless you are an experienced builder who knows all of the challenges involved with solid wood.
Solid wood (every, all) is not very stable, as in it expands and contracts with varying moisture content. Raw wood will absorb moisture directly from the air unless fully sealed on all sides. Most wood will be at it's most stable at 4% to 6% moisture. The only reliable way to measure this is with a moisture meter.
Using sold wood means applying a coat of sealer to the inside of the box as well as the outside. Solid wood is more stable along it's grain than across it, therefore joining two panels with the grain perpendicular (as in the top joined to the back etc.) will cause BIG problems.
The dangers of solid: You build your beautiful pine speakers, with two coats of your favourite stain and 3 coats of high quality polyurethane, mount your new 7" midwoofer and tweeter inset flush with the surface. AWESOME! Two weeks later you notice a crack above and below the woofer. It gets bigger, and bigger as the weeks pass and other cracks open up, especially at the corners... all you effort gone to waste.
This is due to the wood loosing moisture as it was not dry enough to use when you used it.
As well as the box cracking, there is the real possibility of damaging the drivers, literally by crushing them.
Some people find knots appealing, giveing a rustic charm. Knots are the MOST unstable areas of any board. They will warp and distort the board. They can loosen and fall out. They can endlessly leach sap. They are not your friend!
For best results in all your speaker building endeavers, stick with a stable material such as MDF, particle board or plywood. For the most part, veneer will look just as good if not better than solid, if applied properly.
Have fun. |
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| darien87 |
| This is just the kind of info I was looking for. Does anyone know of a thread or site that has a step-by-step breakdown of building a sub box? I'm about to embark on building my first one. |
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| darien87 |
Thanks Mike. Searching is how I found this thread. Unfortunately, I'm at work right now, so I don't really have time to read through lots of stuff. But I promise I'll make time to search more thoroughly this weekend.
Rest assured I'll share my results with everyone. This is my first try, so it might take me a little while. Plus I have almost NO free time during the week, between work, the gym and Kenjutsu, I'm always busy.
My plan is to make the box look like a little end table with a dark brown veneer to match my furniture. I was thinking of even putting a false drawer on it to match the table it will be sitting next to. |
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| mikee55 |
Glad to help, although others here will help you more. I'm still learning myself. Lots to be learnt, I just built a Sealed box and its a Linkwitz Transform jobby. This makes for a small sub, and the Linkwitz Transform is an e.q. that allows the driver some serious bass for a small box, I'm using a cheap 12"car driver from SPLX and its tuned for 20hz. I had a lot of help from richie00boy on here, (Readresearch), he helped me measure the drivers T/S parameters and then I sized my box and tuned everything up. I haven't got an amplifier capable of some power, so I'm using a car amplifier and powering it off a PC powersupply.
Cheers Mike
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| MJL21193 |
| mikee55: Looks good. Is that a computer power supply for the car amp? That have enough "umph" for the job? |
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| mikee55 |
Before I get shot down, this is by no means woodwork. Its a bloody mess, at the end of the day I needed a sealed box of volume. Besides I didn't make it, I was given it. Its the correct size and its airtight. I'm still learning with it.
Cheers Mike |
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| mikee55 |
...230watts, gives 7 amps if I remember right. The protection light comes on and I get a squeak come from the woofer, apparently its underpowered. If you sit in the same room, (5m x 4m x 2m) it booms round the room, travel round the house and you can get a sense that its reaching low. I've had a pair of Goodmans Magnum K2 which have 12" woofers and they didn't do much physical, yes they had a good bass, but not like this. Go upstairs above the room and the floorboards are going for it.
Its mad, can't wait to get myself a serious amp:D |
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| MJL21193 |
| A little further back in this thread you'll see some pics of my version of a Linkwitz transform sub. Used two 18 inch, sealed box - 60 litres. I have a homemade 500+ watt amp, based on Rod Elliot's P68, driving it. Best bass ever. |
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| darien87 |
| quote: | Originally posted by MJL21193
A little further back in this thread you'll see some pics of my version of a Linkwitz transform sub. Used two 18 inch, sealed box - 60 litres. I have a homemade 500+ watt amp, based on Rod Elliot's P68, driving it. Best bass ever. |
Two 18's?!?!? Holy Shiznit! I'll bet that thing can restyle your hair for you. |
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| MJL21193 |
| quote: | Originally posted by darien87
Two 18's?!?!? Holy Shiznit! I'll bet that thing can restyle your hair for you. |
It,s clean SOLID bass. No boom. The box size and the fact that it's sealed make for excellent transients. Moving a lot of air at low frequency is where it's at. |
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| mikee55 |
| ....when I grow up, I want to be |
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| larksp |
arrr
it is nice to know im not the only one to be using car subs.
right now im using a direct x sub
300rms i made a slot port as well like a car tuned to 30 hurts
18mm mdf.... only thing i think i should have done is brace (never done) new to diy) as on lower end films like the heart beat on Pirates of the C 2 the box tends to vibrate alot . music and most film it does sound really good
i use a BK 500rms plate amp.. had been down the line of psu and car amp but it far cheaper for me and more power to just get the plate amp :) as UK car amps are probable more money
i also have 2 JL 10w6v1 what silly really as i like ported and found out there not the best for that hehe
was thinking about tuning and making box for that as well but unless i go slot port using a forums site where it gives u details of each bit wood u need and how goes together.
also will proble just go down the line of the bk monolith sub and then get help for the box
i just enjoy trying to design and all that bits even though i still have lots to learn |
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| mikee55 |
got any pics
Mike:) |
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| larksp |
| yes i have some pics ill add one now |
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| larksp |
and here the one of the inside of the port
any idea's or what u think would be better are welcome
this is used for home audio sub and powered by the 500rms plate amp
thanks |
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| mikee55 |
.....how did you calculate your box and more so, how did you figure the port length?
Would I be hijacking my own thread?:D
Cheers Mike |
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| planet10 |
| quote: | Originally posted by BWRX
I've seen some of the cabs with 2 15s take a 10 foot drop onto a stage and the damage was mainly cosmetic. |
I've done that -- unfortunately the drivers we were using suffered from the concussion and the magnets broke off ... now i always brace the magnet too.
dave |
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| larksp |
i used a car forums site that just made slot port only
it is very simple to use.
just choose the size of the speaker (10inch) and fill in its details
then choose what hz u want e.g 30 and then u can adjust the width
and height.
then other bits u can play around with like the size u want
it shows you what it looks like and gives all the details of sizes or wood and how it would look
shame it does not do the same for pipe vent ..
Net Volume: 1.3 cubic feet
Tuning Frequency: 30 Hz
Port Width: 1.5 inches
Port Area: 18 Square Inches
Port Length: 38 inches
what i went with.
another time would need to brace i think and dunno for home audio if round pipe type ports are better |
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| planet10 |
The single best tip i have on building a subwoofer is to always use a pair of woofers in push-push. The active vibration cancellation goes a long way towards reducing the energy put nto the box. Then all you need to worry about is that the box walls do not pump because of the changes of pressure in the box.
Panel resonances can easily be pushed way out of band where they will not be excited. In this sense a very heavy box is actually counter to the goals (and if you use push-push you no longer need the box mass to stop the woofer from walking)
Here are some general guidlines for increasing panel resonance frequency
> decreasing length and width raise the frequency
> decreasing mass raises the frequency
> increasing thickness raises the frequency
> increasing MOE raises the frequency
> increasing internal (airspace) damping will slightly lower the frequency
There is a dynamic thread that has evolved into talking about box construction philosophies which has some relevant information for this thread)
http://www.diyaudio.com/forums/show...&threadid=98834
dave |
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| planet10 |
Some pictures...
under the sats are the stereo pair of push-push, near aperiodic Extremis woofers
dave |
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| planet10 |
| and the ApexJr suoer8 woofer -- built from recycled scraps, i need to take it out of the system long enuff to put the new feet on it and a couple coats of paint. |
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| planet10 |
| An early push-push aperiodic sub (for 2 Philips 12") -- from before we abandoned using the free MDF and started buying Baltic Birch ply... |
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| planet10 |
| And a development of the above woofer, but with 12" Foster woofers |
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| mikee55 |
Me too, heres a bit of wardrobe in my car.:D
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| mikee55 |
Sorry, that was big, anways, I Had to make a square port, and roughed the hole with my jigsaw. Never again, couldn't cut free hand, a straight line. I should have used a Fence, but I didn't expect it to be any good. I made it for my son, the driver, (10") was a freebie, and it was supposed to go on his PC. I tried it in the car and was so impressed with the noise it made, its stayed there.
To fill the dodgy hole cut, I used PVA and sawdust. Just needs a sand, and paint.
Cheers Mike :D |
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| mikee55 |
Larksp, what forum? Give me a link please.?
Cheers Mike:D |
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| larksp |
yes sure the guy runs it will give help as well if u post ask is this okay or what ever :)
only bad thing they US so there wood mdf is 19mm just so u remember
http://www.subwoofertools.com/forum/ported-box.asp
perfect for car building subs on slot anyway
shame there aint types of programs like this for loud speaker making and sub round port
just nice and simple easy to get what you want and know how it all goes together |
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| djQUAN |
| quote: | Originally posted by larksp
yes sure the guy runs it will give help as well if u post ask is this okay or what ever :)
only bad thing they US so there wood mdf is 19mm just so u remember
http://www.subwoofertools.com/forum/ported-box.asp
perfect for car building subs on slot anyway
shame there aint types of programs like this for loud speaker making and sub round port
just nice and simple easy to get what you want and know how it all goes together |
yep, I used it in my massive sub and it is accurate. although the port area is derived from cone area and excursion, it still makes port noise. |
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| larksp |
yer im sure it does but for the starter is is a really easy guide to getting a nice box
my port noise is ok just the bracing i should have added
cos some of the sides vibrate :) |
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| djQUAN |
| quote: | Originally posted by larksp
yer im sure it does but for the starter is is a really easy guide to getting a nice box
my port noise is ok just the bracing i should have added
cos some of the sides vibrate :) |
in mine, the whole box jumps at very low freq's. |
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| larksp |
if you know of a speaker box program from 2 and 3 way
like this in the sense of tells you all the wood you know and how it goes together by the picture would be great
some of the programs i look at told me like the few details like
11cf
1 driver
vent size
so i worried at don't i tune a tweeter in or just add one in..
and not much more... because im beginner i would like something that tells me all the wood sizes where the port.
my self would like a port of the front.
i know kind of goes into loud speaker than subwoofer but under same topic as building.
looked at some of the kits that give designs but looks liek there all over the place and
and for me dont use some of the drivers i would like to try my self |
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| mikee55 |
I've tried to ask if there is a rule to the size of a box. Asfar as I know, the box is for the woofer alone. Once thats designed, the mid, and or tweeter is added after. When the rest of the drivers are factored in, is all about maths and crossovers. Aparrently it gets better if you go active.
http://sound.westhost.com/articles.htm
http://sound.westhost.com/biamp-vs-passive.htm
http://www.linearteam.dk/default.aspx?pageid=winisd
You may need to cross over to the Loudspeakers section on this site to look at the other Forums.
I tried the calculator on that site, but it asksfor xmax driver displacement and Net box volume, which I don't have.
This is the T/S parameters that I measured for the Longmill
Re = 3.6 ohms
Zmax =50.3 ohms
Fs = 27Hz
Qms = 4.3690
Qes = 0.3368
Qts = 0.3127
fc= 77.5hz
Vas = 99.94 L
E.B.P. = 80.1662
Cheers Mike:D |
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| larksp |
yer i tried winisd
but it dont give u like a box design just that port is so big and then u see the curv
i need designs to make a box
im not good enough to do the rest yet
im thinking about making the BK monolith sub "English one"
more tuned to 20hz for the home system
on the site i gave you with the site to make slot port there is in the forums a part to do driver displacement. but i think then u have to know the measurements of the sub and then it can work it out.
what if you have the driver could just measure it your self
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| mikee55 |
What driver will you use? When I wanted to do things, I just guesstimated everything. If it looked good, it would be good. I saw Thor on Linkwitz's site and fancied ago.I went to Motabitz and bought the SplX for about £40. I bought it purely on the fact it had a fat surround and figured good Xmax. These cheapy speakers never have Thiele Small's printed on the box and besides a Peerless is over £100. I went to B&Q for some mdf, screws and glue. I hit Maplins for the circuit parts and etched a PCB drawn by hand. Obviously I couldn't measure the drivers, so the components for the Transform were the same for the Thor, even the box was the same.
I ran this lot in my car, with an Alpine amp 2ohm stable bridged 4 ohms and 120w, wow did it sound good. Then I turned the engine on and you couldn't hear it outside the car, (Diesel)!
I decided enough was enough, and bought the thing indoors. I hit ebay for a AC millivoltmeter for £15 incl p&p and a kind person on this site (richie00boy) helped with the driver measuring.
My SPLX is now tuned properly. I'm totaly useless at Math and all that but asking on the Forum and pushing myself to try to understand and learn and with the outcome, the buzz and satisfaction far outweighed anything I threw together before.
http://www.readresearch.co.uk/
Cheers Mike:D |
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| larksp |
http://www.bkelec.com/HiFi/drive_un...monolith_du.htm
is the one i want but its for home :) talking to some one thats made one of these with that unit on a different thread and they do sell it in its own box on the site but i have plate amp and that so not spending full out if i can help it.
car subs i would go with the slot port my self and now brace them hehe :)
i do tend to go on looks or what i hear
car subs i have is dont use in a box atm
3 x jl10w6v1 2 like brand new 1 is bit **** now think voice coil might gone might sell one of the working ones if it would go for the right price
and the one im using for home
is a compx directed sub
all are 300rms |
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| richie00boy |
Ah I wondered how the Longmill sub was coming along. Glad to see you are happy with it and obviously getting more confident and learning more. Thanks for the link to my site.
I do actually have a program I wrote that you put your box volume in and it tells you the panel sizes to get cut, but there is a slight problem with it at the moment or I would put it on my website. |
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| larksp |
OOooooo that sounds nice. cos thats my main problem
use a program it tells me either just 11cf and port lenth
i would have to work out the maths for all of it thickness of wood then brace or what ever. and im lost cos i worry about if its right and so on
i then would buy the wood online cut to size mdf only £15 shipping plus the wood all i goto do the holes glue and Finnish :)
and no worries of only 5 cuts at b&q cos of got a tv unit on wait to order wood small shelfs as well so would like to be able to add a box in there 2 for practice then order it all :)
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not saying i could help but one of my family does programming think he mainly done vb and c++ so if it something small or what ever he might be able to help unsure tho
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| richie00boy |
Well if you can tell me some facts I will do you one design. I'll list the info I need from you later when I can access my program.
Thanks for the offer on the programming help. |
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| mikee55 |
....hello sir. I did email you via your profile. I've had to wipe my harddrive buy a new cpu and motherboard. Yes, the Longmill was impressive, because I had to buy a new PC( near enough), I couldn't buy any wood, so I used an old wardrobe. How the amp, is it ready?
Cheers Mike.:) :) :) |
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| larksp |
ok cool there is a link in thred with the driver off the site
http://www.bkelec.com/HiFi/drive_un...monolith_du.htm
this link to the site pain to get it right or it goes to another part of the site lol
anyway this is the driver hopefully i got it right i will have a look
some called marsh on this forums used this for it
Sub is finished, 75l ported, tuned to 20Hz and it's just flippin awesome, better than I could have imagined.
and
95.4 ltr enclosure tuned around 21hz which provides a -3db of 18hz!
http://www.diyaudio.com/forums/show...559#post1184559
there is a picture one one of the guys boxes on there.
next think i want to do is 2 book shelf speakers 2 way but be nice to be able to make my own boxes with a program so i can make more in the future |
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| richie00boy |
Have you bought the drive unit yet? Ideally I need to know the size of the baffle cutout and how deep the basket and magnet is. I can guess the volume the driver will take up but I like to be accurate where possible.
Then I need to know the external diameter of the vent (again you will probably need to buy the drain pipe to get this info) and how long it is. I also need the actual box volume you want.
Finally you must tell me either the width and depth you want so I can work out the height, or the width and height you want so I can work out the depth.
mikee55 - I replied to your message but maybe you didn't get it? |
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| larksp |
yer right now i dont have the driver it was something i would brought a bit later more knowing if i could get a box done first. no rush on it yet in maybe in a few weeks i will probably buy it.
i think because it used in a home system they tend to go for about liek the ones they had made :)
thanks i will get back to you when im fully ready might be able to ask the 2 others that brought one for the info like sub size 12inch :) |
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| darien87 |
Hey folks,
I started putting together my Rythmik Audio 12" sealed box yesterday. I'm about 75% done. It's a lot of work. My back is killing me today.:D
Here's a link to the box specs:
http://www.rythmikaudio.com/downloa...s_DIY_plans.pdf
I test fitted most of the panels, and everything seemed to fit together very well. Well, while screwing and gluing brace #2, I noticed that at the bottom, the edges of the brace do not touch the walls of the box. It touches at the top and in the middle, but down near the bottom, there is a gap of about 1/32". I tried squeezing some wood glue in there to hopefully fill in the gap.
Is this going to be an issue?
Also, I've gotten a few small cracks in some of the edges where I ran screws. Will this be a problem? |
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| richie00boy |
| Did you drill pilot holes for the screws? Did you cut the wood yourself or was it a kit? |
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| darien87 |
| quote: | Originally posted by richie00boy
Did you drill pilot holes for the screws? Did you cut the wood yourself or was it a kit? |
Thanks for the response Richie. Yes, I drilled pilot holes, and yes, I cut the wood myself. |
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