Low minimum impedance? Any upsides or only bad?

[sergeauckland]

I don't follow here. I think you're also confusing efficiency with sensitivity.

Indeed, my apologies...and as a pedant, I'm kicking myself for the error. Edited the above.

S

 

[jEDGEc0m]

Let's be more careful with terms here. The lower impedance speaker may be more sensitive, not necessarily more efficient. Sensitivity is relative to a given voltage input. Efficiency is relative to a given power input. The 4 Ohm version in your example is 3.5dB more sensitive, not 3.5dB more efficient. And to get that 3.5dB higher sensitivity, the 4 Ohm version sucks twice the current from an amp than the 8 Ohm version does. So efficiency is pretty similar between the two. But one requires more current, less voltage, while the other requires more voltage but less current.



For a given voltage input, not a given power input.

Thanks for feedback and improvement of understanding and better terminology. i have edited my post - hopefully it thus is a relatively relevant and useful post.

 

[SHDK]

View attachment 522459

From my antediluvian perspective -- that region from 100 - 200 Hz with ca. 3 ohm impedance at 120 Hz or so is adding needless stress to the amplifier... but I hold old fashioned notions (e.g., loudspeakers shouldn't torture amplifiers).
100 watts into 3 ohms requires 5.77 amperes of current from the amplifier (P =I^2*Z)

EDIT: Fortunately, the phase curve in that region seems pretty benign.
EDIT^2: Practically speaking - play music you like at a level you like for a couple of hours, and see how warm the amplifier feels. Heat is the enemy.

Thanks for taking your time to explain

Is 5,77 amperes a lot for an amp?

Forgive my lack of knowledge, but can you explain how why the face curves is a good thing with these speakers?

I have played music for hours at high but not screaming sound levels. Imagine the volume one would choose for a Saturday while cleaning the house

It never gets more then Luke warm.

 

[antcollinet]

Lets not forget about EPDR value!

You can find more about it here: https://www.audiosciencereview.com/...ereophile-has-started-calculating-epdr.15497/

Some of the KEF speakers get a very low EPDR value, around 2 ohms, which most amplifiers A/B and B amplifiers are not happy to drive.

But lets also point out that EPDR is irrelevant for class D amps. They only care about actual impedance.

I see you've edited to indicate it is Class A/B and Class A amps that suffer (Though actually I don't think it is relevant for class A amps either) - but I'll leave this post up for further clarity.



Sort of related - I also particularly dislike EPDR as a concept. The way it is framed as a lower impedance is particularly misleading IMO. It is not. EPDR lower than the actual impedance doesn't require higher current from an amp.

And it is almost useless in understanding how any particular amp will respond to any given speaker load. In fact if you read the AES paper - it is more framed as a guide for designers to better understand how to dimension the output stage power loss requirements.

IMO it doesn't help consumers at all, at least as far as amp selection is concerned for any given speaker. It might help in selecting speakers that are easy to drive. But then only if you are planning to drive them with a Class AB amp.

 

[Jazigo]

But lets also point out that EPDR is irrelevant for class D amps. They only care about actual impedance.

I see you've edited to indicate it is Class A/B and Class A amps that suffer (Though actually I don't think it is relevant for class A amps either) - but I'll leave this post up for further clarity.



Sort of related - I also particularly dislike EPDR as a concept. The way it is framed as a lower impedance is particularly misleading IMO. It is not. EPDR lower than the actual impedance doesn't require higher current from an amp.

And it is almost useless in understanding how any particular amp will respond to any given speaker load. In fact if you read the AES paper - it is more framed as a guide for designers to better understand how to dimension the output stage power loss requirements.

IMO it doesn't help consumers at all, at least as far as amp selection is concerned for any given speaker. It might help in selecting speakers that are easy to drive. But then only if you are planning to drive them with a Class AB amp.

I concur, a flawed concepts, but it is a indicator for how challenging the reactive load from the speaker will be to a AB amplifier.

 

[wwenze]

Just give it pink noise, measure the current through the speaker, slap a nominal impedance rating and go for lunch

 

[Jazigo]

Just give it pink noise, measure the current through the speaker, slap a nominal impedance rating and go for lunch

Is that you Klipsch Support?