4 Ohm Speakers V s 6 and 8 Ohm

[bleeding ears]

Hello all, hopefully you can fill me in on this topic.

I am aware that an amplifier will produce more wattage when having to power 4 Ohm speakers compared to a 6 or 8 Ohm speakers.

However is there a trade off of some form?

eg If everyone could get their amplifier (or a/v receiver) to produce say 130 watts with a 4 Ohm speaker, instead of only say only 100 watts ,with an 8 Ohm speaker, why wouldn't you go for the 4 Ohm speaker?

The above question assumes that a) Your amp is of sufficient capability to handle 4 Ohm speakers and b) That the sound from the 4 Ohm speaker of your choice is to your liking.

So to sum up my question. Are there any negatives with 4 Ohm speakers compare to 6 or 8 Ohm speakers soundwise or otherwise, there only seems to be positives as far as I can tell.

Any thoughts or info on this topic is welcomed. Dealers can be a bit vague when explaining this topic. So I am seeking info from the knowledgeable Forum patrons out there.

Thanks Pete

[Andrew Pratt]

There's lots of factors at play here as efficinecy can determine how much power you need in the first place. For example compare an 8 ohm Klipsch speaker to a 4 ohm Magnepan and things are very different even though at first glance the 4 ohm speaker might seem to have an edge.

Really there's excellent speakers with all sorts of resistance ratings so its not a good way to judge them...that said if you like two speakers equally the one with lower ohm's or higher effiency might be a smart buy depending on the gear you have.

[Kevin P]

All else being equal, a 4 ohm speaker places a heavier load on the amp. The advantage being, you get more power, the drawback, the amp runs hotter, and it needs to have enough reserve and current capacity to handle a 4 ohm load without clipping or overheating.

Some high-end audiophile speakers are designed with a 4 ohm impedance to make it possible to push more power through them, to compensate for their low efficiency. An 8 ohm speaker requires twice the voltage to get the same amount of current through the coil as a 4 ohm speaker. While this isn't really an issue with home equipment, which can provide a higher voltage, the reason most car speakers are 4 ohm is so that you can get higher power levels out of amps driven by a 12 volt electrical system, without having to use an inverter to boost the voltage.

Also, some high-end speakers have wildly varying impedance at different frequencies. This is probably part by design and part side effects of the design. For example, a particular speaker design might be a tad weak in the bass frequencies, so they compensate by reducing the speaker's impedance at these frequencies to increase the current draw, thus creating a faux EQ to boost the power at these frequencies.

Many subwoofers have 4 ohm voice coils. Some of them may have dual 8 ohm coils connected in parallel, or they may be designed for both home and car use, where 4 ohm is the most common impedance.

[Bent]

I believe the coils in a crossover for 4 ohm speakers can typically be lighter too (half the copper required, so half as expensive to manufacture)

[bleeding ears]

4 Ohm speakers Vs 6 and 8 Ohm

[QUOTE=Kevin P]All else being equal, a 4 ohm speaker places a heavier load on the amp. The advantage being, you get more power, the drawback, the amp runs hotter, and it needs to have enough reserve and current capacity to handle a 4 ohm load without clipping or overheating.


Ok Kevin, so it seems the higher the wattage/current you have on tap the better, I guess I already sort of knew that, but every amp has its own limits right!

Using my 100 watt amp as an example, If a 4 Ohm speaker allows the amp to produce say 50% more wattage than an 8 Ohm speaker, the amp is therefore working harder with the 4 Ohm speaker right!
Consequently, because the amp has to work harder with the 4 Ohm speaker, is the trade off, that the amp reaches its limits (straining) at lower volume levels with the 4 Ohm speaker and sounds harsher earlier than with an 8 Ohm speaker? Remember it is working harder.

Or does the 4 Ohm speaker allow the amp to produce more wattage than an 8 Ohm speaker and therefore allow it to play louder whilst staying just as composed (not harsh).

In summary what I am saying or asking is , a 4 Ohm speaker will go louder than an 8 Ohm speaker (assuming both speakers are of the same efficiency and using the same amp) but is the increased volume at the expense of the amp reaching it's limits (straining) earlier and the sound quality suffering at the same or possibly lower volume levels. (ie clipping or harsh sounding)

A difficult and possibly confusing question and I guess the answer is buy an amp with a million watts, but that isn't within most peoples budgets and they have to get the best out of what equipment they have. For the time being anyway.

So to get the best from my amp which speaker Ohm/efficiency is best 4 or 6 or 8?

Thanks guys!

[Andrew Pratt]

Depends Really its not some thing you typically get to pick in the speakers you like so its sort of a theoretical question. Anyway given the option to design a speaker I'd take a high efficiency model regardless of the ohm rating since that will have more impact on the power required then the nominal ohm rating. Remember that even though a speaker is rated at 4,6 or 8 ohm thats just an average...it'll flucuate a lot over the entire audio spectrum

[blackstar]

What Andrew said

When I first got into Home Theater, I used to fuss about ohm ratings. Go with what sounds best - and if you must quantify it with a number, your better off looking @ efficiency/sensitivity ratings. The higher the efficiency/sensitivity, the less the speaker has to work to get output. Take a look @ something from Klipsch - insanely efficient speakers - efficiency/sensitivity ratings over 93db!

The RF -25's have ratings of 97db - WOW!

[Bruce]

Part of the key is the speaker's Ohms rating combined with the sensitivity rating, not just the Ohms rating itself.

i.e. a speaker with a rating of 4 Ohms/86dB sensitivity will require more power (higher current capability from the amp, e.g. like 45 amps peak/channel) to produce sound at the same volume level as a speaker with 4 Ohms/90dB sensitivity.

Speakers that are less than 8 Ohms benefit from amps that can handle higher currents before clipping. Many of the cheaper amps (especially in receivers) deliver the voltage, but can't deliver the current (amps) to drive 4 Ohm speakers without clipping.

[mcwilson]

Clipping

I agree with the comment about clipping. To give you an example, I have a decent receiver - the Yamaha RX-V2400. I used it to drive 4 ohm center speakers (the JAMO D870s and D8CEN). The receiver did fine for almost all scenarios except battle or action movie scenes that draw a lot of current. The receiver clipped (shut down) several times one weekend not long after I set it up.

Because of my movie tastes, I opted to move the receiver into another room w/ some 8 ohm speakers and purchased separates for my HT.

Not all receivers will have this problem, but it pays to check the impedance ratings of speakers and pre-pro/receivers before settling on a purchase...

Mark

[bleeding ears]

Ok, so the 4 Ohm speaker advantage over 8 Ohm that I thought existed (more wattage from amp) may not be an advantage after all. Thankyou all for your input.

So now , how about those Klipsch speakers, I've heard a pair (not sure of model) and they sounded pretty good with rotel gear.

Do all the Klipsch speakers come with horn style tweeters? and are the horn tweeters ever too much? They sounded ok to me, very clear , but the bass seemed not as tight as similar priced speakers. eg Dali Suite which I am pretty sure are 4 Ohm.

Any comments?

[Andrew Pratt]

Klipsche has a loyal following and they do make some excellent sounding speakers...but they aren't for everyone with their horn tweeters so give them a good listen before buying any.

[Chris D]

My entire system is Klipsch. Yes, all Klipsch speakers are horn-based. I like the sound, others don't as much. They're VERY efficient.