4 and 8 ohms speakers

vnt69

Any ideas why manufacturers design 2,4,6,8 ohm speakers? Beside the fact that the lower the ohm (less resistant) the more current needed to drive it, thus bigger amp.
Take 4 and 8 ohm speakers. Is it true that high end speakers are 4 ohm and mainstream are 8? Is 4 sounds a bit better or harder to make or many other reasons? Just curious.

Frank Z

The resistance value of a speaker really doesn't indicate the quality of the speaker. The deciding factor is the end result that strikes your ear. Don't get to hung up on spec's, even effeciency doesn't have anything to do with sound quality.

chenj16

if 4ohm and 8ohms doesn't matter, so why bother making lower ohms speakers that needs extra current to drive them, no any reason?

Willow

Originally posted by Frank Z
The resistance value of a speaker really doesn't indicate the quality of the speaker. The deciding factor is the end result that strikes your ear. Don't get to hung up on spec's, even effeciency doesn't have anything to do with sound quality.

Frank is right I have some crappy yamaha speakers (wich are going up to the cottage) that are 6 and there is now way in hell they are better than my polks

VR3

I know of a few 90,000 dollar 8 ohm speakers

vnt69

I am not talking about spec or comparing any number. Only about the technical advantages, disadvantages and reasons why they make them 2 - 8.

Frank Z

There's no concrete answer. The speaker design requirements will dictate the appropriate drivers.

jcaut

I'm not a driver designer, but I do know that if you're comparing individual drivers, there's really no such thing as an 8 Ohm driver's "4 Ohm twin". Often a manufacturer will produce drivers of the same general construction in 4 and 8 Ohm versions, but changing the impedance of the coil results in significant changes in many other driver parameters, such that the two drivers really end up being quite different.

Now as for why they would design a driver with a 4 Ohm coil vs. and 8 Ohm coil: I can't answer that. I can only imagine that it somehow figures into the overall design-goal scheme. Perhaps they opt for a lower impedance VC in order to acheive lower inductance, higher voltage sensitivity, different electrical damping characteristics, etc..

The impedance of a speaker system depends on the impedance of the individual drivers and how they interact with each other through the crossover design. Different crossover designs often produce drastic changes in the impedance curve of the system, but the impedance is usually a secondary consideration, with the overall frequency response taking priority.

One other thing that should be considered is that often the 4 Ohm or 8 Ohm "rating" of a speaker system is not an accurate representation of the speaker system's actual impedance. I posted a comparison of the 4 Ohm LSi7's impedance curve and that of the "compatible with 8 Ohm outputs" RT3, in a thread a while back. Here's a link. If you take a look at that, you'll see that the RT3 could be just as easily called a 4 Ohm speaker. It's actually lower, overall, than the LSi7. This is just one example, and it's not just Polk that does it. Nominal impedance of a speaker system is not so much a "spec" as it is a general comment on how difficult a speaker is to drive. I think it's sometimes mis-stated a bit, maybe for marketing reasons. Bottom line is I'd use it (the impedance) as a guide when pairing a set of speakers with an amp, because that's really how the speaker manufacturer intended for it to work.

Jason

organ

Originally posted by chenj16
if 4ohm and 8ohms doesn't matter, so why bother making lower ohms speakers that needs extra current to drive them, no any reason?

Depends on the drivers, cabinet, design, etc. A designer may come up with something that sounds great but because of the drivers, design, etc chosen, the speaker may be 4 Ohms nominal. On the other hand, another designer may have something that sounds just as good at 8 Ohms nominal because his design and parts are different.

Maurice

gregure

As stated above, it is not the design of the speaker over all, but the design of the drivers that dictate the Ohm load. For instance, a lot of softer dome tweeters, or even ring radiators such as the LSi's, have 4 Ohm impedance ratings, because of the amount of power it takes to drive them adequately. As you might have noticed, these types of tweets tend to have a softer, more musical quality than a titanium tweeter, which is almost always brighter and more dominant. Not to say titanium tweets don't sound good, it's just that they have a different sound.

When it comes to speakers, they all operate at different impedance levels depending on the source-sound reproduction ocurrs at many different impedance levels, but some speakers operate at a lower impedance on a more consistent basis.

All in all, though, a 4 Ohm impedance really means that you shouldn't even think about running such a speaker with a run-of-the-mill amp, or a $500 Onkyo receiver, as they just aren't meant to drive speakers of that quality.

Whether you have a 4, 6 or 8 Ohm speaker, however, they all sound better with a great amp. The more juice you feed them, the better they'll sound. Once you go high end, you won't go back.

2+2

Jason, thanks for your insight...your link was very interesting....