4 ohm or 8 ohm. Whats better? - AVS Forum
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post #1 of 15 Old 06-10-2003, 02:38 PM - Thread Starter
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Well I am interested to know what is better 4 ohm or 8 ohm speakers. I have some speakers that are both 4 ohm and 8 ohm and it is very hard to match them unless all of them are the same ohmage. I know 4 ohm speakers are more demanding on amps and play louder but is there any advantage to them?
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post #2 of 15 Old 06-10-2003, 03:35 PM
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You pretty much have it.

Although, I would be careful about saying that 4 ohm speakers are always 'louder' you still need to take into account the drivers and the sensitivity of the speaker.

A 4 Ohm speaker presents a bigger load to an amplifier (less resistance) and therefore an amplifier that can dip down will give you more watts running a 4 Ohm speaker than an 8 Ohm. However, if your equipment isn't stable down to 4 Ohms, you could burn out the amp or cause undue distortion.
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post #3 of 15 Old 06-10-2003, 03:45 PM
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most receivers are targeted to deliver to an 8 ohm load.

4 ohms can really stress the amp.

But there isn't necessarily a correlation between ohms and loudness.... that has to do with speaker efficiency.
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post #4 of 15 Old 06-10-2003, 06:54 PM
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4 ohm drivers are also a less damped load so they pose more problems to the amplifier than just additional (twice) current demand.

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post #5 of 15 Old 06-10-2003, 09:01 PM - Thread Starter
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then why would a manufacturer even make a speaker 4 ohm as apposed to 8 ohm. Why not have a standard ohmage and everybody goes by that. UNLESS one is better than the other..................
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post #6 of 15 Old 06-10-2003, 09:19 PM
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I'm gonna try to answer (postulate) and others PLEASE comment on my findings.

When building a speaker you always have compromises. Sometimes design decisions are made on those compromises.

4 ohm speakers are no "better" than 8 ohm speakers. But many times good crossovers and drivers (read good speaker) will produce a speaker that is 4 ohms or less.

Its no that less impedance is better, more so that it is a product of design. The designer thinks "who cares what the impedance is as long as the crossover does what I want and the drivers produce the sound I want"
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post #7 of 15 Old 06-11-2003, 05:52 AM
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Question:
How does one find out if the amp/receiver they have can handle 4 ohm versus 8 ohm speakers? I have a Harman Kardon AVR 525 that I would like to use with some Whatmough M30's. The website and manual for the receiver do not mention anything about speaker impedence at all that I am aware of.
Also, although probably not optimal, would it hurt to have 8 ohm speakers in my setup temporarily (while I find the cash to replace the old 8 ohm speakers) as long as I do a fine job with level and crossover adjustments? Thanks for any help, insight, and suggestions.

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post #8 of 15 Old 06-11-2003, 06:46 AM
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Speakers are not purely resistive loads, and to have just two categories...4 ohm and 8 ohm...is too simplistic. A speaker that claims to be 4 ohms probably dips to 3 ohms or less at some frequencies, and rises to 30 ohms or more at some frequencies. Some 8 ohm speakers even drop to below 4 ohms at some point. This is plotted on the speakers impedance curve. If you're concerned, take note of "minimum impedance" and "nominal impedance" both. And try to stay away from amplifiers that can't handle a 4 ohm load. They are Nancy Boys.

In addition to impedance, there are other properties that may make a speaker easier or more difficult to drive. It's not as simple as "4 ohm" and "8 ohm."

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post #9 of 15 Old 06-11-2003, 07:23 AM
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Paul,
Thanks for the response, but, could you possibly know whether my amp (or that line of amps) can handle 4 ohm loads? I have the H/K AVR 525. I have written US technical support about it, but I don't expect a response for several days. They don't have a very good record with me. Thanks a lot for your time.

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post #10 of 15 Old 06-11-2003, 07:51 AM
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i have seen plenty of people say the hk 525 can easily handle 4 ohms. HK amps in general can all handle 4 ohms.
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post #11 of 15 Old 06-11-2003, 08:34 AM
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Dan,
I've done an in-home audition of 4-ohm speakers with my HK525 and there was no issue. During the audition, I definitely cranked 'em too! The HK fan kicked on a few times but the sound was warm and clean.

I only hooked up LR mains with 4 ohm speakers. If you had a full 7.1 setup with every speaker 4 ohms, then *maybe* you might overstress the HK. For casual listening at less than reference levels, you should be OK.

Anxious to hear what HK replies back with, though.

Hope this helps,
Guy
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post #12 of 15 Old 06-11-2003, 08:41 AM
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Thanks Guy. I was real particular when I sent a message to H/K as well, so we should get a pretty good idea. I explained that I was buying new 4ohm LR speakers and that I would be using them temporarily woth 8 ohm speakers as well, but, eventually that I would like to get a matched set. I am using the entire 7.1 setup and would like to replace all the speakers eventually so, if the receiver can't handle it, I don;t know what I should do. I'll keep you posted though.
By the way, I also asked about reference levels when trying to use the EZset function of the remote with a 4-ohm/8-ohm setup.

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post #13 of 15 Old 06-11-2003, 11:37 AM
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Dan, if you look at my initial response, you'll see that one 4 ohm speaker will present a totally different load to an amplifier than another 4 ohm speaker. The impedance varies with frequency. A speaker that's 4 ohms at 20 Hz may make an amp puke, while a speaker that's 4 ohms at 1 kHz may not be a problem. Then you have the properties of inductance, capacitance, weird phase angles, inefficiency, etc. You are looking at but one parameter. It's almost like asking "What car gets better mileage...a brown one or a white one?...or a Toyota??" ;)

h/k comment: Historically, harman/kardon receivers have been able to handle tough loads, but the current universal trend in receivers is to put out as many "watts-per-dollar" as possible into 8 ohms. Most new receivers won't tolerate speakers that dip below 4 ohms or that have a nominal 6 ohm impedance. I suspect the new h/k stuff is still better-than-average in this regard.

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post #14 of 15 Old 06-12-2003, 12:56 PM
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If the 4ohm speaker is a subwoofer your talking about you had better have a high current amp to drive it as bass frequency,s use more power than the rest of the audio range, considerably more.

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post #15 of 15 Old 06-12-2003, 01:09 PM
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Well this is the response I got back from H/K unfortunately:

"Hi Dan,

While all of our receivers are UL approved for 8 ohms only, they can also handle 4 ohm speakers without any problem. The receivers will run a bit hotter than normal, but they can certainly handle it and do have a form of thermal protect. You may want to put a fan on the receiver, if it runs very hot.

As for running both 8 and 4 ohm speakers, it is no problem and you don't have to worry about making changes for the EZ Set remote setup.


I hope this helps."


Kinda tip towing around the answer I think. Hmmmm.

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