Understanding Loudspeaker and Amplifier Impedance

This article gives information on understandingpowerful car amplifiers will work into a 2 Ohms load
loudspeaker impedance (resistance) which is(often refered to by the manufacturers as being 2
measured in ohms, and how to match loudspeakers toOhms Stable. However this application is rarely
a suitable power amplifier.encountered since it would need 4x 8 Ohm Speakers
The information is relevant to any music system,to be connected to each channel to acheive this.
including in car entertainment, Home Cinema Systems,Working out Ohms:-
Band pa rigs and Mobile DiscosMost Music, Hi-Fi, Disco & P.A loudspeakers are rated
A Channel on an Amplifier refers to the individualat 8 ohms, so connecting one 8 ohm speaker to one
module or circuit inside the amplifier which takes in achannel of the amplifier will present a load of 8 ohms
signal mono low level signal and boosts it to drive ato it.
loudspeaker(s).However most automotive loudspeakers are rated at
All Stereo amplifiers have two Channels, one channel4 ohms.
handles the left hand signal and speaker, the otherPlugging in an additional 8 ohm loudspeaker into either
obviously does the same for the right. Other thanthe existing connected speaker or the second socket
some amplifiers sharing the same power supply, theon the same channel of the amplifier (if fitted) will equal
internal Left and right channels or circuit boards are8 ohm + 8 ohm = 4 Ohms load to the amplifier.
seperate, which means in the event of a loudspeakerTo get 2 ohms you would need to connect:-
problem or component failure the opposite channel8 Ohms + 8 Ohms + 8 Ohms + 8 Ohms = a 2 Ohm
should continue to work.Load, so to get your amplifiers 2 Ohm rating you need
Some Amplifiers used in home entertainment or Hometo connect (4x) 8 ohm speakers to it.
Cinema systems have four or five output channels.Given the fact that each channel is identical and
These essentially work just like stereo (2 channel)seperate, your Amplifier has the capability of running 4
amplifiers, but use additional outputs to drive front andx 8 ohm speakers per channel! - a total of 8 speakers
rear loudspeaker pairs, and either a subwoofer or- which is why I said to ignore 2 ohm ratings when
center channel for surround sound applications.buying an Amplifier and concentrate on the 4 or 8 ohm
Okay - the load which determines how much powerwattage ratings!.
your amplifier provides to the speakers is dependant2 Ohms of load on the Amplifier can also be acheived
on the actual number of speakers connected and theirby connecting (2x) 4 Ohm loudspeaker cabs to the
individual impedance.same channel.
The load is called the impedence, and the level ofIn Hi-Fi Applications, it is also common to find 6 ohm
impedence is measured in ohms. Most hifi and lowand 4 ohm loudspeakers for sale in the marketplace. If
power PA amplifiers will only work to a minimum of 4your amplifier is rated at 4 ohms minimum load, then it
Ohms however some professional PA or Discois wise to just connect a single speaker to each
amplifiers such as Peavey, and QSC etc and somechannel to avoid overload.