Ohms

[Scott]

<font color='#000000'>Can someone give me &quot;non-techie&quot; explanation of speaker ohms (8,6,4) and their performance relationship to amplifier power....?</font>

<font color='#000000'>As I understand it . . .

An ohm is the unit of opposition to current flow. &nbsp;It is a unit of resistance. &nbsp;RESIST. &nbsp;RESIST. &nbsp;The lower the number, the greater the resistance (4 ohms is twice as resistant as 8). &nbsp;The greater the resistance, the more your amp is asked to work. &nbsp;Believe it or not, a speaker works by resisting current.

Most receivers are content to do enough work to &quot;push&quot; current through an 8 ohm load. &nbsp;When a speaker with more resistance (6/4/2 ohms) is connected, the receiver's amp has to work much harder to push that current into the speaker's innards. &nbsp;When the amp isn't up to the task, it goes into thermal overload (overheats), sends a distorted signal, even blows a speaker.

Why 8 ohms as the accepted mass standard? &nbsp;Dunno. &nbsp;Possibly because 8 ohms is mathmatically enough resistance to make drivers reproduce sound from 20Hz-20kHz. &nbsp;

Basically, if the speaker is too resistant, the amp can't get the signal through; if it's too &quot;loose&quot; (16/32/64 ohms) then the drivers may not work hard enough to produce acceptable sound.

For your sake, and mine, I invite any technophiles to correct or improve upon my offering.</font>

[RDL]

<font color='#000000'>Speaker impedance directly affects an amplifier. * A lower impedance results in the amplifier having to supply more current. *This is because the relationship between power and current is:

* * * * * * * * * * * * * * * I^2( R ) = P
I = current
R = impedance
P = power

With this in mind, a speakers impedance only limits your amplifiers maximum volume level. *The lower the impedance, the lower the over all SPL level your amplifier will be able to produce before it clips. *You should also know that a speakers impedance rating is usually rated in &quot;nominial&quot;, which means when the speaker is standing still. *All speaker impedances change throughout thier frequence response.

An example:
Say a speaker is rated at 6 ohms nominial, *it is possible that it could drop to 4 ohms or even 3 ohms at lower frequences like 90Hz.*

Not really a big deal, *but if your amp can't handle such a low impedance then odds are the amp will clip. If you buy speakers with a low impedance, make sure you buy an amplifier that can handle them. *This well result in the best performance from your system.

I hope this helps.</font>

<font color='#000000'>Puzzled about the Orvis statement... &quot;The lower the number, the greater the resistance (4 ohms is twice as resistant as 8)&quot;. That ain't the way the truth. The higher the number, the higher the resistance. A pure short (0 ohm), has no resistance. Actually a speaker is rated by impedance. Impedance is the restriction of AC current flow. Resistance is usually the restiction of electrons in DC. Music is AC.</font>