8ohms vs. 4ohms

phish phunk · Not So Newbie Joined: 13 Aug 2003 Posts: 5

when something says it can handle a certain amount of watts at 4ohms and another amount of watts at 8ohms, what does this mean and why does it matter?

Also, whats the difference between paper cone drivers and aluminum cone drivers?

Neil Gray · Posted: Wed Nov 05, 2003 5:09 pm Post subject:

I'm shrugging my shoulders with you. Confused

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2slick4u · Big Hamster Joined: 07 Sep 2003 Posts: 97

ohms are the impedance on the speakers. (the amount of power that they can handle)

a 4 ohm cab is alot more powerful than an 8 ohm cab because it is allowing more power to go thru, but it is closer to 0hms (the breaking point, when your speaker cracks) so basically the more ohms u got the less chance there is of it cracking, but you'll get a smaller amount of power out of them. 4 ohm will be louder and more powerful but you got a much better chance of cracking a speaker.
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phish phunk · Not So Newbie Joined: 13 Aug 2003 Posts: 5

hey 2slick thanks for the info, but do you also by any chance know about my other question, what advantages you get from paper cone drivers and aluminum cone drivers, and what the difference is?

PorkChops · Kitten Joined: 01 Oct 2003 Posts: 137

First off, let's clear up a few misconceptions. The impedance of a speaker is merely a rating of its resistance to electrical flow, it has no bearing on the speaker's power handling capability or how loud the speaker will be. A 400 watt 8ohm speaker is just as loud as a 400 watt 4ohm speaker of the same model. Where speaker impedance comes into play is when it relates to amplifier output. Solid state amps can handle any level of speaker impedance as long as the impedance isn't lower than the manufacturer's limit. Let's take a GK 400RB for example. The 400RB delivers its max power of 200 watts into a 4ohm impedance. GK says don't use a speaker load of less than 4ohms because the amp will fry. And indeed it will because as you drop the speaker impedance on a solid state amp, the amp just keeps putting out more power. If you were to put a 2ohm load on a 400RB it would put out more than its rated 200 watts and fry the output transistors in the bargain.

Does that mean you have to use a 4ohm load? No, you can use higher impedance values if you like, but as the speaker impedance rises amplifier output drops. A 400RB while delivering 200 watts into a 4ohm load only delivers 130 watts into an 8ohm load.

Having said that, none of this is true about tube amplifiers. Tube amps have output transformers that matches the amp to the speaker load. Very often a tube amp will have speaker outputs on the back allowing for a range of impedance levels, 4ohm, 8ohm, 16ohm...ect. These jacks are actually different taps off the output transformer. Tube amps differ from solid state amp in another respect as well, running lower impedance cabs on a tube amp does not yield more power output. It's also important to match the speaker impedance to one of the taps on the tube amp or you risk cooking the output transformer.

gibson_thunder · Posted: Thu Nov 06, 2003 5:55 pm Post subject:

very well put, porkchops!
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CaptainSaveAHo · Bear Cub Joined: 10 Jan 2003 Posts: 647

Paper vs, aluminum? Aluminun/titanium drivers have very stiff cones. Paper is still fairly stiff, maybe throw kevlar in here too, and plastic is the worst. In general, a stiffer cone puts out sharp bass, no flexing of the cone. Nothing worse than muddy bass. Unless of course that's your bag ^_^.

gibson_thunder · Posted: Thu Nov 06, 2003 6:13 pm Post subject:

I revel in the thunder-mud, my friend... I am a BassPig!!! Laughing

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CaptainSaveAHo · Bear Cub Joined: 10 Jan 2003 Posts: 647

Ah! I see, one of *THOSE* players Razz

PorkChops · Kitten Joined: 01 Oct 2003 Posts: 137

Metal coned speakers are also subject to something that isn't much of a factor for paper coned speakers...metal fatigue. Hartke cabs are famous for blowing drivers. Some guys love the sound and are willing to put up with the expense and inconvenience. If you decide to go with aluminum drivers, carry a spare. Smile

gibson_thunder · Posted: Thu Nov 06, 2003 6:28 pm Post subject:

yes, I am one of the mighty defenders of the Thunder-Mud, one of the slayers of the twang-bass, one of the keepers of the sacred Gibson! RAAAWWWRRR!!! Twisted Evil

ok, I drank too much mountain dew tonight... Very Happy

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Mkuk0 · Posted: Sat Nov 08, 2003 12:07 pm Post subject:

Keep it up Gibby I need to laugh right about now.

Mkuk0
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scorpionldr · Posted: Sun Nov 09, 2003 10:08 am Post subject:

lol, maybe if you had a fiver you'd be a bass pig or maybe if you detuned a fiver all the way to F# like Ryan Martinie of mudvayne used to do. lol, until then, drop d is like nothing.

gibson_thunder · Posted: Sun Nov 09, 2003 2:51 pm Post subject:

no drop-d here...straight 4 string, EADG-tuned Gibson Thunder-mud whoop-*Horse's Patoot*... Razz

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CaptainSaveAHo · Bear Cub Joined: 10 Jan 2003 Posts: 647

I used to downtune to CGCF and drop D, but I'm sticking to EADG anymore too. My amp starts farting down there anyhow.