As others have said speaker claimed impedance is nominal - tge actual impedance will vary across the frequency spectrum, in some cases quite substantially. You don’t need to “match” speaker impedance to amp rating directly, you just need to know that the amp is happy to drive speakers that go however low the speaker’s impedance goes - though that information is often not readily available! It is probably safe to assume that with transistor amps no ‘8 ohm’ speaker will cause problems, but it is possible a ‘4 ohm’ speaker will trouble some amps, though decent amp manufacturers often clarify how low they are comfortable.
But whether an amp can ‘grip’ the speaker well and maximise control is something not easily gleaned from many specs, though power that doubles or nearly doubles as impedance halves, and with a low output impedance, would seem likely to be very capable …the question then, is dies it sound good?! The advantage of active speakers is that they take take all the guesswork and assessment of the amp out of the equation - you know the amp is exactly what the speaker needs, and audition is built into auditioning the speaker.)
It was!!! It was a free translation. In french we say that to a person who can do what others cant. Your calculation of all those numbers was impressive!
And for the sake of it, i do understand that speakers do not have fix 8ohms impedance. And maybe i was not clear on my saying, english is not my first language, but if companies sell speakers rated at nominal 8ohms (suggesting amps between 50 and 125watts for example) and amps are nominal 100watts with 8ohms speakers, lets just say its a safe assumption that is where one should aim. Taking the 4ohms or 2ohms amp capabilities maybe informative to some audiophiles, but for my humble needs i would stay with the safe nominal rating. I sold my 200watts/ch Azur840w (awesome amp by the way) for downsizing consideration.
The post is very interesting @anon66195540, I’m glad you created it as it helped me to clarify things.
By the way I was wondering if it’s possible to understand what the peak power is for each amplifier. For instance in the product specification of the NAP S1 it’s pretty clear that a 9kW burst is possible. But what about a Supernait 3? I don’t see it, it’s only reported this :“80W per channel into 8 ohms (4mm sockets), 130W per channel into 4 ohms”. So I can only consider the ratio @gthack reported here:
I was curious about my amplifier (Exposure 3010DS2) but I couldn’t find any useful data.
Power vs ohms are not the peak power. It is continuous delivered power depending of your speakers resistance. You can have different peak power (watts) for different resitance (ohms). For example the Nait 50 as a nominal continuous power of 25watts in 8 ohms, 40 watts in 4ohms and 60watts in 2ohms. But it has a awesome 225watts of peak power, resulting in a lot of dynamic capabilities. Another example, NAD’s D3045 stereo integrated amplifier outputs a continuous 60 watts per channel into 8 ohms and 4 ohms, but its Dynamic Power, sometimes called Peak Power, hits 80 watts into 8 ohms and 150 watts into 4 ohm.
What i found for you Exposure 3010 was 110watts continuous power and 165watts dynamic power.
We often mention that the doubling of power between 8 ohms and 4 ohms is a good indicator of a hefty power supply.
What I do not understand is that Naim is famous for producing very good power supplies, however none of their amps double their power ratings between 8 ohms to 4 ohms? Besides Naim amps (which I absolutely love) are not particularly considered to by high current amps as most of them are equipped with 4 capacitors of 10 000 μF each.
That’s where its getting complicated. There is no one magic formula. Different companies have there own way of doing amps. Voltage, Ohms, continuous, dynamics (peak) is different from one to another.
Another example would be the Benchmark AHB2 with a 100watts continuous power and a dynamic range of 132db = 120 watts. Not a lot but, but AHB2 is considered a really impressive power amp.
You’re right that bar Statement, Naim’s power amps aren’t as powerful as some produced by others (especially some of the US stuff). The 500(DR) is a regulated amp, which has an output limited due to the design philosophy employed by Naim in its making. With the new 350s, there’s been a change in design (now with parallel output transistors – which a 500 doesn’t have, as Naim have always been concerned that getting these properly balanced was a challenge).
The really teasing part of the amplifier power debate is understanding 2 things IMHO:
1- what power & current supply does your loudspeaker really need to make it perform to near/at its optimum — it’s not new news that manu’s specs for their speakers can be highly misleading e.g. for B&W’s 800 series, they cite min amp power of 50W (up to 1000W!) – but it’s not really about watts?!
2- the value which is gained from having an amp which can deliver (1) i.e. not looking at the specs and thinking the amp is ‘good enough’, as a much higher powered amp really delivers, even in to what might be considered less-demanding speakers.
I would say Naim amps punch above their weight (vanilla specs) for the reasons which have been stated above, but I wouldn’t hook up anything less than a Statement with a pair of B&W 801 D4s. A 500 will drive them, but in no way optimally.
The Stereophile reviews of amps are my go-to resource, as their technical reviews highlight what a speaker demands from an amp (and demands is the right word). There are some amps which are 8-ohm spec’ed but can dive down to ~3-ohms when the woofer & bass lines start opening out. This is why the trinity of your room (size/listening position et al), amplifier and speaker is so challenging to fathom out, and home dem’s are a must.
Speaker sensitivity and impedance, ie. ease drive, are far more imortant factors in terms of the final nature of the sound than amplifier specs.
As has already been mentioned here, amplifier wattage ratings can be very misleading indeed and tell you very little about the final nature of what you will hear.
What actually needs to be carefully considered is the combination of amplifier and speakers, rather than either in isolation. Not just the paper specs, but the actual nature of the sound of each device.
For instance, my Klipsch Forte III speakers are horn-loaded in the mid and HF and have 99dB efficiency. My amp is rated at 100W/channel at 8ohms. You might expect such a combination to be easily capable of generating very high levels - and indeed it can! Yet this really tells you little about the actual nature of the sound, and about how it will sound at more reasonable levels.
My Moon amp is very nimble and fast sounding. The speakers, being horns, have a very immediate, keen and responsive sort of sound. The end result is a sound that, even at low levels, is amzingly fast, dynamic and direct, without any sense of it receding into the boxes as can often happen at low levels. With many amp/speaker combinations one needs to play them at reasonably high levels before the music comes alive - not so this one!
What I am really trying to say in perhaps a roundabout way is that, as has been known for decades, paper specs tell you very little indeed about real world performance characteristics. I have never much bothered with them beyond getting the basics right.
Only listening is the finality of it. But sometimes its not possible. You have to go with what your hifi seller has in store, or take a guess based on reviews!
FYI, many years back, I read recommendations to pair a 500(pre DR) with Wilson’s bookshelf speakers, as these were reported as being a very good marriage. Size isn’t everything, as the saying goes!
Not that I remember – probably 88db-ish. The proposal was based more on the synergy between the kit. As has been said above, it can be a lottery. I had Dynaudio Contour 1.8mk2’s (tweeter and 2 mid/lower units in each). The blurb said ‘stable 4-ohm load’ and ‘Danes don’t lie’.!
Well, these speakers caused the fan on my 500 (pre DR) to run, when various other speakers hardly caused it to get warm. When the 500 first came out, I understand Naim’s view was that the cooling fan should come on rarely. Well, a dealer I encountered, who used theirs to power large Usher speakers, said the fan was on a lot of the time.
Impedance curve dips (often down to 2-ohms and even below) can be very nasty things.
I thought you could guess the peak power from that ratio, I do understand that power and ohms are not the peak power. However my knowledge stops there.
Where did you find the dynamic power of my amp? I couldn’t find it at all.
This surely gives you an idea of the amp behaviour, of course it’s not the whole story.
One interesting experience I had, with Bryston 4Bsst feeding PMC EB1i on bass, was that the clipping LED would illuminate briefly on peaks when playing loud (85-90dB average at listening position, peaks 115dB or so). My reading of the specs suggests that it was trying to exceed 500W - which is consistent with received wisdom that the speakers really needed Bryston’s 7B or higher.
