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Two Halves (Read 31512 times)
wayan
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Posts: 42
Two Halves
08/06/07 at 10:12:36
 
Hello all,

so here goes my first post~

so far the WO is my top pick for my experimental first sub woofer. after reading almost the complete WO forum i get the impression that this is a very successful design. however I'm really curious to know if anyone has ever tried making half of a wicked one...

my reason for this is because the space in my room is rather limited, and i was thinking of making two halves, and placing each under my current speakers.

however since this is only my first week that I've been hunting the net for sub designs, and never actually owned one (sept the 2.1 computer speakers Grin ) let alone built one, id say I'm quite a nubee to this.

workshop wise and wood working skills wont be an issue, since i work for a furniture company, and have the workshop at my disposal, plus the workers.  ;)

so, if anyone has tried, or has enough experience to say that building two halves of the WO is a bad idea, please let me know, and ill stick to the original design, and eventually build two of them or something.


thats the rendered image of the 36 x 24 box. I'm thinking of placing it between my TV console and the TV itself, so it just props it up a bit. however I'm a bit skeptical about how well my TV will handle the vibrations...

i might have to just put it in the corner of the room, unless someone suggests me to try out the split module idea. here is another render of what i have in mind:



any feed back will be greatly appreciated!
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« Last Edit: 08/07/07 at 04:44:26 by wayan »  
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buzz
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Re: Two Halves
Reply #1 - 08/06/07 at 13:05:15
 
You have changed the size of the horn mouth with your split design. It will not play down to the original WO lower frequencies.

Welcome to the forum! And thanks for your nice illustrations.

buzz
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« Last Edit: 08/06/07 at 13:07:48 by buzz »  
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Gexter
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Re: Two Halves
Reply #2 - 08/07/07 at 02:40:00
 
I am not as scientific as everybody else but I have done some messing around with the design.
If you have depth you could try extending the horn mouth so the mouth is the full width of the half the WO front. This could help increase the output, I have my doubts it will lower the freq but  it may a little. The port that vents the compression chamber is in a large part responsible for the Freq IMHO. I have messed with this aspect in the WO and it kills the output but seems to help lower the freq and flatten it out with less peaks but less over all range. I think Steve hit a real balance that is a ideal starting point and it has some minor flexibility. If you go to far your not going to have much luck with the balance of SQ,SPL and output that Steve has already put time into.

To be honest there has been a great deal of talk of splitting the WO but I have not heard back to see how well it has worked. I think I can recall one person that felt it worked out for him. I think if he heard a full one he may change his mind.
The whole benefit of the WO is in the shared horn/Flare, without that is not a WO at all.
Just build a ported box but a 1/2 WO would have a cool factor.

kudos as well on the illustrations

Gex
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wayan
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Re: Two Halves
Reply #3 - 08/07/07 at 04:42:35
 
Ok, so ill stick to the original design, i don't want to waste time and money building something that has not been really tested before. in the long run ill probably end up building two of these baby's.

so~ first step accomplished, chose my design.

this morning i went and bought the drivers, 2x 10" umm... probably a local made sub, but it wasn't the cheapest in the shop, so i hope that it does not disappoint me. paid Rp. 250.000 for each them (thats US$ 27 each) nothing too crazy, and if everything fails (i hope not) i haven't spent a fortune on it. here are some images of the drivers;






the box didn't have any specs, but from what I've understood, the WO works with prity much any sub driver out there.

i also tried to find an appropriate amp as well this morning. i went to about 5 different electronic/music shops here and was not able to find any panel amps eg;


which is a pity, cos that would be the easiest solution... instead i think i have to build my own amp... (good thing we have an electrician here, who will be helping me a lot i think lol)

so what I've found are some mono, or stereo amps, the best one I've seen (quality wise) seems to be a 2x 400W amp. its prity much just the circuit board, one page instruction manual, and the heat sink... from there ill need to buy or build a suitable power supply,  24v(for the amp) + 12v (for the safety circuit) @ 5amp? he he... totally new to this. anyone have any advice regarding appropriate power supplies? I'm almost tempted to just buy a car amp from the car mod shop at this point. however the price will be a lot higher i would imagine, and how to power that? just a 12V something amp converter?

then there is also another little gizmo that they had that adjusts the volume and frequency. however i was told that i don't need that since ill be running the signal from my Yamaha amp that has a SUB-Woofer out plug (mono), and it should be set to the right frequency for sub usage. ill have to read that up in my amp manual exactly what the parameters are of that sub outlet.

just ordered two panels of MDF 18 mm (we don't use inches here  ;D) but thats about equivalent to 3/4" when i get it this afternoon, or tomorrow ill start cutting them down to size, if i remember i might take some pictures.

I'm thinking of using both Lamello, and screws to fasten the main structure, and then just screw the top on so its possible to remove it on a later date. by the way, what is recommended to use as sealant when placing the top on (so its possible to remove later)? i have my doubts that it will be such a perfect fit as to be air tight...


"lamello joint"

thanks about the info Gex n Buzz, and hope to hear some more from everyone  ::)

cheers!
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« Last Edit: 08/07/07 at 05:37:11 by wayan »  
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Adrian
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Formerly known as
'Adrian D.'

Posts: 250
Re: Two Halves
Reply #4 - 08/07/07 at 06:40:58
 
Lamello looks nice, but if you're using screws, i really can't see the point. try to get your hands on some adhesive.
as far as sealing the edges, i like to use sawdust mixed with glue.
you don't need to use a plate amp. any amp will do.
as long as you know what you are doing, DIY amps are a good choice.
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Too much bass never hurts, or does it ?
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wayan
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Posts: 42
Re: Two Halves
Reply #5 - 08/07/07 at 07:22:58
 
So lamello is out then, was just thinking of extra durability/sturdiness... ill see, if we got enough biscuits lying about i might use some, otherwise just stick to screws.

i heard that wood glue doesn't stick so well too MDF, is that correct? should i maybe go all out extreme and use epoxy? he he...

i just got the price for a sheet of 3/4" MDF, 20 bucks  :( i thought everything should be cheaper here, a friend of mine told me he can get a sheet for 15$ over in the states... bah.

so now I'm waiting to find out f i can get plywood or MDF for a cheaper price than here from the neighboring island  ;)

regarding the sealant, I'm wondering what to use to seal the top on, since from what i've understood, this should not be glued and just screwed on, so its possible to open up later on for repairs/upgrades.

to keep the price down i think i will have to stick to a DIY amp, make another little box for it as well, and sit it on the floor somewhere.

if i get a Mono amp, do i just splice the output and plug em into each sub? how about a Stereo Amp? since my sub out is Mono i guess i just splice the output of my Yamaha amp, into my new amp (well "to be built amp"), then run a cable to each woofer from the amp. correct?

thanks  :D
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wayan
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Re: Two Halves
Reply #6 - 08/07/07 at 08:27:19
 
Ok, so a sheet of Particle Board costs like half the price of MDF, i've ordered two sheets which should arrive tomorrow. I've been told its a good material for speaker boxes, just easer to break if they are dropped or built badly~

is that true?

here is my HT setup (not much, but slowly growing):


Yamaha, RX-V340
specs are:
  • High power 5-channel discrete amplifier configuration (80W x 5 Max)

  • Dolby Digital Matrix 6.1 and DTS Marix 6.1 compatibility plus Dolby Pro Logic II decoding

  • Powerful 32-bit Yamaha LSI (YSS-938) for CINEMA DSP processing

  • 21 surround programs (41 variations) with SILENT CINEMA and Night Listening mode

  • 96kHz/24-bit D/A conversion

  • Speaker A/B selection

  • 5-band center graphic equalizer



not sure what the specs for these are, cant remember. however they sound quite good with the above amp.

i then plan to eventually get a center + two surround speaker after i build the WO.
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« Last Edit: 08/07/07 at 09:08:03 by wayan »  
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Bart_West-VL.
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Re: Two Halves
Reply #7 - 08/07/07 at 10:42:29
 
Hey Wayan,

MDF is very good for glueing, don't worrie about it!
You could just glue the whole box without screw, it would be a challenge to line the corners up and press everything well together, but the glue is realy strong and more then sufficient.
You do have to give it some time to dry of course.

To seal a side that has to be removable use weatherstriping, works very well.
When the lid is screwed on, it's almost invisible because it's pressed flat.
Or just put it upside down on a carpet, seems to play at its best this way
you need a flat floor, no bumpy tiles etc.

I made a few Velleman amps before, have a look at there website, nice stuff, not the cheapest though.

If you like to use a stereo amp:
Take the mono/sub out of your Yamaha.
Go to the input of the stereo amp with a splitter and feed left and right the same signal.
Then use one output side for one driver in your WO and the other channel for the other woofer.

happy building! Smiley

Bart

Particle board is weaker, maybe you should use those biscuits now, but that's more work and glue.
If you don't plan on dropping them from the stairs, it should be ok.  ;D

edit: be sure to predrill holes for screw, specialy with paricle board.
If you use a lid, you should use those metal threaded pieces instead of just screwing directly in the wood.

Velleman dealer in India:
(maybe that's the nearest, so not a good solution for you?)
VPL Infotech & Consultants
301 Savitri Sadan II 15 Comm Centre Preet Vihar
110092, DELHI
INDIA
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« Last Edit: 08/07/07 at 11:16:41 by Bart_West-VL. »  
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wayan
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Posts: 42
Re: Two Halves
Reply #8 - 08/08/07 at 02:06:04
 
so here are some more questions for you all;



with that drawing I'm hoping to clarify two things, firstly:


how should i fasten the sub? i noticed that my sub has a rubber seal on the front, side, but if i were to load it like in Eg. Red, i would have to get some sealant around the back. however i noticed most ppl seem to be loading them like the Red speaker, is there a reason for this? or can i load it like Eg. Blue?  [smiley=tunes57.gif]


then, the walls creating the chambers, do i build them in (as in the red) or out (as in the blue lines) of the guide lines?


i also noticed that the 2" x 2" reference does not match up with the X lines as they would be if i were building a 36" x 36", do i still start from 2" x 2" corner, or where the line intersects the X lines~


[smiley=waaaht.png]   so many little things that kept me awake half the night, he he...

thanks,
w.


did a bit more forum hunting, and came by 8bit-ash's construction images. to satisfy my curiosity, i took it as my sample, and constructed the outlines from it.



I'm able to see that he built the walls as per the Red line of my drawing further up., and placed the speakers as per the Red sub. what if i decide to make the support double thick, wont the the sub be moved further up, and then maybe run out of space? or do i add the second support layer towards the sealed chamber (thus making the volume there smaller).

thanks Smiley
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« Last Edit: 08/08/07 at 04:21:55 by wayan »  
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Bart_West-VL.
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Re: Two Halves
Reply #9 - 08/08/07 at 09:27:04
 
For someone who read almost all of the WO post, you seem to have a lot of questions that are already answered or are clearly explained in the plans.
B.
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wayan
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Posts: 42
Re: Two Halves
Reply #10 - 08/08/07 at 09:47:59
 
most of the threads are a jumble of images without much regarding the measurements. true that the instructions are clear, but what i asked (i checked again and cant find a note on that in the instructions) was if the walls were measured in or out of the guide lines. anyhow, i think ill follow it like 8bit-ash made his, it was also how i thought i should be done.

as the motto goes "measure twice, cut once" i just want to be sure my measurements are correct before i use them, lol

only thing i am still not sure about is how to mount the drive... yes this is the first time I'm constructing a speaker case of any sort. so i got no experience regarding what the difference in the placement of the two speakers will do. i need to make the mount double the thickness since the particle board does not seem to be overly strong when its put under pressure close to the edges.

and regarding "having read almost all the threads" hmm... id say i read three quarters of them, but some of them didn't make much sense to me (nubee here~), so i just skimmed, or skipped them. probably where i missed the previously posted answers to my questions Tongue

gonna start cutting the boards up tomorrow. didn't have time to get a start on it today, only drew up some measurements on the sheets.

cheers,
w
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Bart_West-VL.
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Re: Two Halves
Reply #11 - 08/08/07 at 10:09:49
 
Yes, I forgot this is you're first build, sorry Wayan! Embarrassed

Particle board is indeed not strong on the edge, otherwise it's a good and cheap box material.
Use lots of glue to fill in those little air pockets on the sides of the board.
Consider using polyurethane based wood glue!

The boards go inside the lines, but that depends what you think of as being 'inside' of course. Roll Eyes
If you look at those different little drawings, you can see the box itself as if it was a faint shadow, it's clear that these thick faint lines run on one side of the drawing lines.

good luck!
B.
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Blotch
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Re: Two Halves
Reply #12 - 08/14/07 at 02:06:49
 
Yes the walls go "inside" the lines as per your red lines. Glue is amazingly strong on mdf. I had a helluva time disassembling a speaker box to recycle the wood into another box after it was glued. Good ole #2 drywall screws and acrylic caulk are usually what i use. Makes it pretty cheap Smiley. Those drivers look alot like pyramid drivers. Hope they work well Tongue I still haven't had the time/money to build a full blown WO *sigh*. I DID make plans for a 1/2 WO. The dimensions came to 24x24 inches and the mouth came out very different. The sealed chamber shrunk from about 1.1 cubic feet to around .6 cubic feet (my diamond sub will work perfect in that Smiley ). I'll have to draw it out for all to ponder on. Good Luck Smiley
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wayan
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Re: Two Halves
Reply #13 - 08/16/07 at 02:49:32
 
so i went on another shopping trip to get together all (well most) of the hardware to build the amplifier. this is what i was able to get for $55.00



thats the power supply, 5A, two heat sinks (don't want noisy fans, so got em big), power cord, fuse, power switch, cable connector thingos, some electronics for the power supply (no clue what they do) and the input connector to go from my Yamaha amp to this amp.




this is the amplifier that seemed to be the best they had over there ($20 for it, out of the $55 i spent). there were some 1000 or 2000W amps, but the owner of the shop said it was just fake, probably like 2000w p.m.p.o. or something. anyhow, the components on this one looked better. i still doubt that this thing has 2x400w (800w) of output, lol... ill be happy if its able to get a bit of rumble out of the WO.

so, back to the drivers, this amp is not strong enough to power my double coil 4Ω 300w subs, so the shop owner told me to link the two connectors on each drive in series (to get 8Ω), and not parallel (to get 2Ω), since that would probably cause the amp to blow. is that correct?

i also just realized last night that i totally forgot to get a volume control for this thing, ha ha... i think its possible to adjust the volume from my Yamaha amp, however i think i am going to go and get a volume control, maybe even an equalizer (if its not too expensive) so i can even use the amp for other speakers in the future. so, for those electricians out there~ how do i hook up the equalizer/volume control? between the sub-out and this amp, or between this amp and the WO?

i still haven't finished cutting the particle board, almost done tho, just need to cut two more little pieces, and ill have all the components ready. then ill have to cut the angles.

i have decided that ill use Epoxy glue during assembly, i also want to fill in all the edges of the particle board with epoxy, since that seems to be the most likely spot to get damaged. it only needs a little bump and the edges/corners start to flake. I'm thinking of veneering the whole thing on the outside to make it look better. still need to see how much that would cost, if not ill just have it painted black with a glossy finish.

ill take some pictures of the assembly process. might have the time to get it started today.

cheers,
w
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Bart_West-VL.
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Re: Two Halves
Reply #14 - 08/16/07 at 20:43:27
 
Hey Wayan, looks like you're doing good there!
+1 on the noisy fans and big heat sinks!

I will try to answer a few of your questions.
Those big cylinder shaped things are capacitors to even out the voltage ripple after the rectifier.
The rectifier is that square block with four pins.
Series connection on the DualVoiceCoil is correct, make it 8ohm.
I would think this amp gives 400W MAX in 4ohm, so expect no more than 100W RMS in 8ohm, still good! difference between 100W and 200W is only 3dB!
Volume control or equalizer go's between you're Yamaha and this amplifier.

A tip: if you want better dynamics, double those capacitors up in parallel.
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