***8 OHM DRIVERS (great info)***

[Slammed 5,000+ posts]

Great thread on 8ohm drivers and their efficiency....

http://www.diymobileaudio.com/forum/showthread.php?t=31

Click to read more...

 

[Worlddre 5,000+ posts]

good read!

 

[AcidicDreams 10+ year member]

yay... the IDW's are just bought are 8ohm.... of course that means I need to run them both //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif (where am i going to find 400w @ ohm) ohh darn...

 

[thadman 10+ year member]

are they DVC or SVC?

You could run them at 2ohms if theyre DVC

If theyre SVC you could run them at 4ohms bridged off a 2 channel amplifier

 

[Lakota 5,000+ posts]

Look at sig.//content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

 

[CBFryman2 5,000+ posts]

i learned exactly nothing from that.

and his logic is off.

Running an amp that could possibly produceing 1000W @ 1ohm (especially when trying to get loud) @ 8ohm to only yeild 125w is like having lance armstrong pedal a single speed tall geared bike up a hill. Not like not using all your money in bank accound. The power potential is there but you dont have the torque to acheive it.

Also, rating 4ohm driver rated at 2.83v with a 90dB efficency compared to an 8ohm driver with the same efficency at 2.83v is mroe like the 4ohm driver having a 87dB efficency since the true SPL rating is sapposed to be 1w/1m not 2.83v/1m

also, the drive wont get twice as loud, it will be 3dB louder with the same given power input which you just slashed in half because you are running your amp at a higher impeadance so sonic output will essentially be the same. all othe things equal.

all in all just get 8 8ohm drivers and call it a day //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

 

[thch 10+ year member]

cone = mass

move mass. need force.

force = BLi

if L doubles, i halves.

simplified. debate.

 

[jujumantb 10+ year member]

Running an amp that could possibly produceing 1000W @ 1ohm (especially when trying to get loud) @ 8ohm to only yeild 125w is like having lance armstrong pedal a single speed tall geared bike up a hill. Not like not using all your money in bank accound. The power potential is there but you dont have the torque to acheive it.

To a point, but he is more gearing his info to a 4 vs 8 ohm debate, he does mention 2ohm aswell.

Also, rating 4ohm driver rated at 2.83v with a 90dB efficency compared to an 8ohm driver with the same efficency at 2.83v is mroe like the 4ohm driver having a 87dB efficency since the true SPL rating is sapposed to be 1w/1m not 2.83v/1m

There is no "true" rating, they are often rated using different units. Point is, by the very nature of an 8ohm coil, they have the capability to be more efficient, and they usually are.

also, the drive wont get twice as loud, it will be 3dB louder with the same given power input which you just slashed in half because you are running your amp at a higher impeadance so sonic output will essentially be the same. all othe things equal.

He never said anything about getting twice as loud, they would, theoretically, be about the same loudness, but with using much less power with an 8ohm sub . And the power wouldnt be "slashed in half" Power compression would raise the impedance high enough on the lower compression driver so that a 4 vs 8 ohm nominal impedance subs would actually be much closer than that.

PS your spelling is terrible! //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

 

[jujumantb 10+ year member]

also, the drive wont get twice as loud, it will be 3dB louder with the same given power input which you just slashed in half because you are running your amp at a higher impeadance so sonic output will essentially be the same. all othe things equal.

Forgot to add this:

Doubling power will NOT double your acoustical energy (or your "sonic output" //content.invisioncic.com/y282845/emoticons/tongue.gif.6130eb82179565f6db8d26d6001dcd24.gif ). It takes 4x the power to do that, well, actually MORE than that due to compression and the like.

 

[squeak9798 5,000+ posts]

There is no "true" rating, they are often rated using different units.

Yes, there is.

SPL = 112+10*log(9.64*10^(-10)*Fs^3*Vas/Qes)

 

[thylantyr 10+ year member]

The article talks about drivers and people automatically assume subwoofers.

The driver sensitivity issue is more interesting if you look at tweeters and pure

midrange drivers.. for subwoofers it's a different can of worms to analyze because there is more going on.

I have some planar tweeters that are 13 ohm, 103dB sensitivity, mids are 8 ohm

100dB sensitivity, compression drivers with horn lense with even higher ratings.

None of these are typically used in car audio, many people don't even use it

in home audio, but the stuff exists. Point is, you can get loud with few watts with

high sensitivity drivers.

 

[squeak9798 5,000+ posts]

Horns = teh shizzle

I miss mine //content.invisioncic.com/y282845/emoticons/frown.gif.a3531fa0534503350665a1e957861287.gif

 

[CBFryman2 5,000+ posts]

Yes, there is.
SPL = 112+10*log(9.64*10^(-10)*Fs^3*Vas/Qes)

which, in theory, is a 1w/1m ratig. //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

His logic was off, which was my point.

 

[jujumantb 10+ year member]

Yes, there is.
SPL = 112+10*log(9.64*10^(-10)*Fs^3*Vas/Qes)

And in what units does this formula come out in?

 

[iagrdshaka 5,000+ posts]

Good reading, but I dont believe some of what he said