General question- why are most speakers 8 ohm instead of 4? - AVS Forum
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post #1 of 9 Old 02-14-2013, 06:25 PM - Thread Starter
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Maybe there's a super simple answer to this one. But why with alot of amps being stable into 2 ohms these days are they still using 8 ohm speakers? Why not make them 4 ohm so that we can pull more power out of the amp. I do realize that many receivers might hate that, but who's plugging a nice pair of diy speakers into a receiver anyway. It seems like everyone is using pro amps, or at least a lot of guys are. Anyhow, just curious.
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post #2 of 9 Old 02-14-2013, 08:24 PM
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"who's plugging a nice pair of diy speakers into a receiver anyway."

i would guess that most folks who diy a set of speakers still plug them into a receiver.

you have a good point though, why give up 3db all other things equal.

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post #3 of 9 Old 02-14-2013, 09:25 PM
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Briefly and Basically - With Increased current flow comes increased heat. Heat shortens component life.

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post #4 of 9 Old 02-14-2013, 09:48 PM
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What about increased distortion? Its not always about max output.
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post #5 of 9 Old 02-14-2013, 10:02 PM
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Honestly, a lot of reason for me using 8 ohm and even 16 ohm AND high effeciency speakers is to be green. I know I know. It's pretty insignificant. But it keeps my amp running cool. I can run them off my AVR. I never worry about upsetting the amp. And it keeps my electricity bill just a little lower.

Even my subs will likely be wired 8ohm load when I finally upgrade. They're wired 8 ohm right now, but more because the amp isn't 2ohm stable.
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post #6 of 9 Old 02-15-2013, 12:43 AM - Thread Starter
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all points noted. But serioulsly, if using a fan cooled amp that doesn't break a sweat into 2 ohms and produces great sound quality into 4 ohms, why not? so then you don't have the issue of heat. If you're using pro amps, they still produce great power into the lower ohm load with low distortion... just thinking out loud over here.
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post #7 of 9 Old 02-15-2013, 12:44 AM
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I think it comes from the Pro Audio world and most amps being 8 ohm stable back in the day.
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post #8 of 9 Old 02-15-2013, 05:06 AM
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Unless one has spent some time building/repairing amplifiers: It may be hard to understanding the implications of low impedance loads. When the impedance is dropped the current flow goes up. All conduction paths, wire, semiconductor junction have set current capacity ( ampacity ) . These don't get physically larger to accommodate the increased amperage when the amp load is reduced.
It's easy to look at short term stability and forget long term impact.
As mentioned performance suffers at low impedance.
Pro Sound amps are built for fault tolerance as the working conditions vary as does the expertise of operators that may made mistakes on the road ( through accident or ignorance ).
Because sound is logarithmic - it is easy to forget that the extra power ( from low impedance ) does not translate to a large increase in SPL but a rather a small increase in headroom in the region of the top of performance envelope where distortion is highest.

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post #9 of 9 Old 02-15-2013, 07:25 AM
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Quote:
Originally Posted by rr14 View Post

Maybe there's a super simple answer to this one. But why... are they still using 8 ohm speakers?
So you can use more than one.
Quote:
Why not make them 4 ohm so that we can pull more power out of the amp.
Because most speakers aren't power limited, they're displacement limited, often to half the thermal rating. And watts are cheap. In short, you don't need to pull more power out of the amp.

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