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.