2. amps-preamps
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the 4 ohm rating

im a little confused as to why buyers choose 4 ohm products.

now here's what got me thinking about all of this 4 ohm stuff.

i took a pair of mids into my rebuilders shop the other day to get new surrounds installed & we started talikng audio & he told me that about 75% of the blown driver's he takes in for rebuilding are 4 ohms & the other 25% was split between 8 & 16 ohms.

correct me if im wrong but when you run a amp in 4 ohms as opposed to 8 ohms isnt the amp working much harder to produce the inflated wattage at the lower ohms? & isnt a amp thats getting worked hard a bad thing?

the same goes for 4 ohm speakers,the 4 ohm rating only makes the speakers to appear to be more efficient & also creates the need for thicker cabeling for the lower ohm's.

i hope the answers can remain civil as i didnt start this thread to be a smart ass but i am wondering what(if any)advantages there are to having 4 ohm gear over 8 ohm gear.

take me to school here & learn me somthing because all im seeing is drawback's to owning 4 ohm gear.

mike.
128x128bigjoe

Showing 3 responses by eldartford

eldartford
4,262 posts
 
Six of one and half a dozen the other. The greater proportion of 4 ohm drivers reflects the fact that most drivers (these days) are 4 ohms.
eldartford
4,262 posts
 
A speaker voice coil has inductance as well as resistance. An 8 ohm coil, in order to produce the same force from less current must have more turns...twice as many. This means twice the inductance. Not good.

Magneplanar speakers don't have voice coils. The wires that move the diaphram are glued on flat, so there is little inductance, and that makes Maggies an easy load for the amp to drive, although they do benefit from lots of power.

Some drivers are made with a split voice coil ...essentially two coils at say 8 ohms each. You can hook them up in parallel or in series, and have a 4 ohm or a 16 ohm driver. It has almost no effect on the way the driver works. The choice is made based on how the driver is used with others in a system.
eldartford
4,262 posts
 
Phasecorrect...One of my sons did in fact drive a 4 ohm low efficiency speaker (KLH 5) with a clock radio. I told him it wouldn't work, but it did! Not a great deal of volume, but what there was sounded loads better than the clock radio speaker.
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