Hello

Steazo

Member
Joined
Jan 12, 2007
I am a newbie here and a newbie DJ. I've waited until I have turned 41yrs old to decided that DJing is for me. Having said that I would appreciate any help I can get. Which brings me to a question: If you have a set of speakers that are rated at 500w RMS @ 8ohms but the amp is rated at 350w ohms RMS @ 8ohms but at 4 ohms the RMS rating is 600w can I run speakers rated for 8ohms at 4ohms for more power?
 

soundlight

Well-Known Member
Joined
Oct 27, 2005
Location
NJ & NYC
Welcome! I'm sure that you'll find lots of info here.

Well, the deal with the speakers is that a standard 2 or 3-way speaker is an 8-ohm impedance. Two speakers wired in series (connect power amp to first one, and power out from the first one to the second) is a 4 ohm load. So no, you can't get 4 ohm power on 8 ohm speakers. I'm not a crazy speaker theory person, but I can tell you this: a speaker can only be driven at its specified impedance, because it will not be able to provide the lower impedance for the amp.

I'd really recommend that you pick up a copy of "Audio Made Easy (Or how to be a Sound Engineer without really trying)" by Ira White from Amazon.com. It's quite possibly the easiest read for beginner audio folks, and is a textbook for many beginner sound courses at college that I've visited. It'll explain a lot of stuff.

But you are always welcome to ask questions here.

EDIT: Gah...Twice in a row...it's PARALLEL, not SERIES for those impedances.
 
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CHScrew

Active Member
Joined
Aug 16, 2005
Location
north of Pittsburgh, PA
Welcom to CB. I think soundlight pretty much sumed it up. Also, I've read "Audio Made Easy" and it is really good.
 

Chris15

CBMod
CB Mods
Premium Member
Departed Member
Joined
Jul 15, 2005
Location
Sydney, Australia
Welcome to Controlbooth.

Just to be picky, you are in fact running the speakers in parallel...

And about running an 8 ohm speaker at 4 ohms. To put it simply, you can't. Let us for a moment ignore the fact that we are talking about an AC impedance and say that the speaker had 8 ohms DC resistance. Now that resistance is basically a factor of the amount of copper in the coils of that speaker. So it is very hard if not impossible to change the resistance of a speaker. Now for these purposes we will say that AC impedance works the same way as DC resistance. (It is more complicated but essentially it works the same.) So you can't take an 8 ohm speaker and magically make it into a 4 ohm speaker. However if you paralleled another 8 ohm speaker, then you would end up with a total resistance of 4 ohms by the fact that 1/ total resistance = 1/R1 + 1/R2 + ... if that makes any sense. Hope that helps...
 

dvlasak

Active Member
Joined
Nov 3, 2006
Location
Wisconsin
ADd we to the Control Booth "Welcome Wagon". 41 or 14, what does age matter? Except that at 14 it was much easier on the body to do certain tasks that we have to do in our jobs!

Dennis