wayan wrote on 11/26/07 at 01:17:22:
Bart

Cool, almost done.
One thought: Why didn't you fill the little holes in the particle board before finishing?

I would get a frame the size of the whole throat side and then use magnets to fix that stealth thingy on there  :D

Well it's probably a bit late and so on but there is a WO thread and there is a 'halve' WO i found.

http://www.mobileelectronics.com.au/forums/index.php?showtopic=77268&st=180&star...

well i thought it might fit here.

d-uh~ Velcro!

thanks Bart, that saves me a lot of skull scratching action

we have plenty velcro here that i can use.

the frame for the fabric is ready, at this point i only need to glue on the fabric, and then fix the velcro.

thanks for that
peace,

Very nice work, especially for your first build!!

I forgot, or missed it, but how large did you build it? Full size (36x36) ?

20Hz is very low for this box, but it's good that you still hear it, but I think it will be a lot lower in volume at this frequency!

Rattling window can be fixed with caulk.

Congratulations!! This worked out very well, I'm jealous!

i finally managed to take the time and read the instruction manual for the Yamaha amp, and got the Sub out working!


this is what my setup looks like atm (center and surround speakers still missing). I'm moving to a new house in 2 weeks, and there i plan to fix the L/R main speakers to the wall, close to the ceiling, so the position will be the same. then ill have to experiment with the WO position. at the moment i don't really have a choice when it comes to the position of the WO. i just placed it where it fit, ha ha.

sadly the amp that i built is really under powered   the two 10" subs are just a little power hungry, and the "build it yourself" amp parts are not powerful enough. comparing it to my Yamaha amp (both with normal stereo speakers) i think the amp that i built is a little less powerful. so considering that the Yamaha amp is like 70W RMS per channel, i guess the one i built is probably around 50~60W per channel.

i have tried tweaking the setup, so that the Sub is running at its max volume, and set the two main speakers to -20dB. but even then the WO is not really producing enough sound compared to the main speakers. only when i crank up the whole system does the WO start doing its thing.

i have the feeling that i need to upgrade the amp at this point... without buying a complete new one however, how should i go about it? when i was building it together with the electrician, he told me that the capacitators that i bought were really low quality, and that i shuold eventually consider replacing them for a big sound improvement. would that also mean that the amp would be able to increase in the output? or is it just the quality of the sound?

in the case that replacing the capacitators will get me more watts, (being a total newbee to this any advice is always appreciated) what kind should i look for?



these are the four capacitators I'm using at the moment, paid about $2 a piece.

last week while at a music shop i noticed that they had many different kinds of capacitators. some were almost the size of coke cans! is bigger better? lol

ideally would be to also have a sub equalizer I'd imagine, so that i can increase the low frequency gain, and reduce it closer to the cutoff. not sure ill be able to find the right components tho. just a more powerfull amp would be a good start i think.

If you already say it's underpowered, then upgrading the elco's won't do much, if anything.
Besides, better quality is relative for sub only. Sub's need power, so your amp will never give enough, sorry.  :(
Even if these elco's are low quality, the fact that they are doubled parallel, gives them better reaction time (meaning: half the resistivity)
More would give more punch, dynamics. But the volume won't change! Only power can change that.
If you can rotate the sub, try that too and what 60_and_up said.
Maybe the placement is just bad or your listening position.

From now on, it's experimenting time, let the fun begin!

Bart

I assume you made the classic mistake most people want to make, he he.
Different power numbers for the same amplifier can have huge differences.
http://en.wikipedia.org/wiki/Audio_power

the amp that powers the WO (the one i built) runs of the "Sub out" from the Yamaha amp that i have (which automatically cuts off at 90 Hz).

with the Yamaha amp, i can connect up to 5 speakers (for 5.1 surround sound). i cant really switch the the amp around cos then i would loose the ability to use the remote (no remote on the home made amp) and i would have a hard time with the cables too, since i have like the DVD player, cable tv, and radio on Yamaha amp, and only one input on the home made amp. anyhow, what i'm trying to say is that its not possible to change the layout without getting a really 'awkward to operate' sound system!

the only option to improve the WO at this point is to get a stronger amp, which is something i cant afford at the moment. there are no cheap second hand shops selling amp's, nor can i buy it from E-bay, cos i don't have a credit card atm, and to ship something all the way to Indonesia would probably cost more than the amp itself!

in truth the WO does get loud! (with the amp i made), but only when i turn up the whole system, which i don't really want to do, cos the neighbors would probably end up lobbing bricks at my house! lol

Peace~

yeah, i already did that, I've adjusted the 2 main speakers volume down to the max i could, -20dB

its already a noticeable difference, but not enough, lol

silly power hungry WO

I'm happy with the WO, and look forward to trying the face down position when i get it to the new house.

i even got a complaint from my girl friend when she was not able to figure out how to switch on the WO, and had to watch a movie with out it, ha ha i guess its not only me that notices the difference

Hey Wayan!

Are you OK? Just heard about the quake in indonesia.

You didn't cause it with your WO I presume?!  ;)

Bart

Good to hear you're fine.

Another important thing I found. (you know I sit at the computer night and day, doing research for you! )

"A 75dB SPL signal on the LFE channel will be 3 times, or 10dB, smaller than a 75dB SPL signal on the other channels. It will only sound correct when fed to an amplifier that amplifies LFE by 10dB more than it amplifies the other channels."

That's why you're WO sounds a bit silent I guess.

Here's the link to the article:
http://avsforum.com/avs-vb/showthread.php?t=748147

My opinion is 80Hz, so your 90Hz Yamaha would do fine, at least for me.
Higher cutoff could let you hear where the sub is located, not a good thing, only if you center the sub it could be ok.

If you double the rms-power, you get +3dB
So you need about 10 times the power to get the right result, or you have to bring down the other channels by 10dB

Bart

wayan wrote on 12/06/07 at 05:15:09:


can you split the audio signal before it gets to the yamaha? and run it straight to the sub amp?  = 2 seperate amps,

this may require  low pass filter of some kind?

unless the amp you built has 1?  (filter)

if your home made amp is kinda cr@p anyway, try 1 ohm and see what happens, it should make the amp provide much more power to the subs, might kill the amp, but at lower listening levels it might live.????????  and you can fix it if it breaks cos you built it right

wayan wrote on 12/11/07 at 02:13:02:


if you point it towards the floor or into a corner, most of the higher imformation kinda gets filterd out and all thats left is bass.

p.s. you cant wire 2 x dual 4 ohm subs too 8 ohms.  can you get a dmm (digital multimeter) and see how many ohms your drivers are showing the amp?

also you dont have to open the wo to mess with the ohm load, just rewire the wires outside of it.

You DO get 8 Ohm but what 60 says is, the WO with both drivers will get you 4 Ohm.
What you're saying is, the resistance of ONE driver, not the total box.
You drive it with a stereo amp, each driver one channel.
60 drives his with one mono amp, both drivers together.

Did this come over understandable?  :-[ Sorry for the poor vocabulary.

a multimeter costs $10,

is your subwoofer amp stereo or mono?

you should have 4 wires coming out of the wo. that means you can connect to the amp 2 different ways,

paralel or series.

you have each speaker wired for 8 ohms so,

paralell = 4 ohms final load,

series = 16 ohms.

i think

its worth trying,

my understanding is that if the amp doesnt like the load it will go into protect mode and not just blow up  

i kept the wires that go to the two drivers separate. if you look at the image i posted of my finished WO you will see that i have two connectors, one for each driver.

the amp i have is a stereo amp. the SUB out from my Yamaha amp is mono, so i put a splitter on it, and then run the "stereo" wires into the stereo amp i built, and then the amp has two output connectors, which i wire up to each driver on the WO.

so what i think i have is practically two 8 ohlms mono amps powering two 8 ohlm drivers that is fed from the same source... could splitting the mono sub output into two separate channels be a cause for the seemingly low power of my WO?



there, thats my little sketch of the day, depicting how i have wired everything together.

peace,

ps, i guess i could buy myself a multimeter, they can be useful for many other things. how would i use one to check the ohlm of a driver? O.o  

never owned one, and hardly ever used them sept to try and see if it could detect a current going through my finger if i poked myself hard enough, ha ha.

ill just leave it the way it is for now.

when i save up enough money ill get around to buying a new amp. or maybe ill be able to find a second hand one in Europe when i go next month.

not sure if ill have much time to look tho, since im going to be up in the Alps snowboarding most of the time

cheers.

woot! a fellow boarder

ill be going to Switzerland for about 2 weeks. gonna be there with my brother, father and some other friends, should be a lot of fun!



cheers,
wayan

ps, im sure the only problem is that my amp is under powered... well the imput into my amp isnt powerfull enough, so its output is low, so with a bigger amp, that should be resolved.

i just moved however, and i ended up putting the WO flat on the floor (under my chest of drawers) with the mouth facing my bed. its already better. (still cant find a conventiant spot to put the WO in a face down position )

i was thinking of something like that, just a lil amp to strengthen the signal some, ha ha, wasn't even sure if something like that existed...

i think that would just be too messy... my stereo stack is already getting too tall!! let alone adding another little box for a pre-amp

i shouldn't have told you guys that my amp wasn't powerful enough, you guys are loosing more sleep over it than me!

I'm getting my speaker stands soon, they will be fixed to the wall on the two corners of my room. should be getting it some time this week. found it at a friends house who wasn't using a pair that he made, and gave them to me. just need some slight adjustments, since those were extending of the wall too far.

ill take another pic of my new room once that is installed! the new house i moved to is great! its nice going home to a proper house

cheers!

OOO...I know the new house feeling. I just moved into my new home a couple weeks ago - gratz . Well...a simple solution, although some peeps don't think they are reliable, would be to purchase a plate amplifier such as this one:

http://www.partsexpress.com/pe/showdetl.cfm?&Partnumber=300-804

Wire the speakers in parallel and viola - 4 ohm load which will match the amps 4 ohm output specs which in this case is 240 watts. I personally doubt the drivers you have will handle 150 watts each for extended periods of time so 120 watts each should be fine. Keep in mind manufacturers of low-mid grade speakers tend to embellish the power ratings. I have had a 100W plate amp running my subwoofer (1 12" radio shack 12" car sub in a 9 cubic foot ported box tuned to 22 Hertz) in our house for 2 years and haven't had a lick of problems other than our kitties chewing on the patch cord. Good luck

initially i wanted to use a plate amp for the WO. i thought that it would be the easyest solution, to just have it built straight into the sub (dont think it would fit tho)

however i was not able to find one here in Bali. so thats why i got stuck making my own (being that i wanted to avoid spending lots of money buying an of the shelf amp.

id have to ask around to find someone with a big amp that i can borrow to actually test it out and see if it would be the right solution.

for now im just leaving the setup as it is. just need to get round to eventually buying 3 more speakers for the cinema surround sound. after that, if ive eventually saved up enough$$, i might go and get me a better amp. at the moment im just totally broke (due to paying a years rent for the new house).

have a great week end guys, take care!

actually, one of the speakers was marked wrongly, they switched the red and black markers around. i noticed the mistake when i was testing the speakers shortly after i bought them. i switched it around and checked all the other connectors, they are all the right way round. ive done the single driver test as well, they are both working. ive switched the polarity around in the end, since i loaded the drivers backwards, and it seems to sound better this way.

lately in the new house, i have had to actually turn the volume of the WO down a touch, the new room layout seems to have improved it a fair bit.

yesterday i finally had the satellite dish hooked back up to my decoder, so we can watch tv again, he he... at the same time i wired the two secondary speakers to the living room. now i just have to hit the A-B button and i can switch the speakers from bedroom to living room, rather than moving the speakers out of the bedroom, like i was doing for the 1st week since we moved.

did a little shopping yesterday, got brackets and fixed the living room speakers to the wall, and did several other little jobs around the house.

when i turn up the speakers in the living room, the WO is really noticeable in the bedroom, since its thumping away on its own, end up having to turn it down a lot, lol

whats great about spending money on any audio system is that it does not go out of date the way for example a computer does! i bought this sound system like 3 years ago now, and just adding the WO now for a relatively cheap price, i get a great improvement, and still i am able to improve the system further by getting the surround speakers for when i watch movies... its definitely money i do not regret spending  (unlike computers that are outdated in 3 months, and usually break after a year or two)!!  [smiley=ahhhhhhh.GIF]