How much POWER do you have?

[Eric L]

The reason to have more power is to keep everything clean at higher levels (not just constant levels but dynamic).

Tenson, I agree with what you say here, but I'm not sure how asking about user's amplifier power is much help to you as a speaker designer.

What I'd think you need to know from the user (and it's admittedly hard information to get since most people can't measure it) is:

A. what is your typical listening level?, and;
B. at what distance do you listen?

You also want to know crest factor of the music, but this is reasonably constant (I would say 20 dB minimum; acoustic instruments show up to about a 23 dB crest factor).

As Martin said early in this thread, exponential increases in amplifier power produce only relatively small increases in volume. I would add to that that small increases in distance from the speakers can produce exponential decreases in volume (inverse square law).

So small changes in either A or B will quickly result in large changes in required amplifier power. Enough so that the range of amplifier power that people are going to report is not very significant, in comparison.

Speaker efficiency is the big variable you have control over; if you stay away from inefficient speaker designs, then that will most likely let you reach your objective, as a designer.

 

[Markus S]

"If the first Watt's crap what's the point in 'avin any more?"

Anthony Matthews, Tube Distinctions.

I believe this particular thought originates with Dick Olsher, an American reviewer and constructor.

Keith Howard wrote an excellent article exploring the concept in the Dec 2005 edition of hiFi News - not available online as far as I know - and came to the conclusion that the first watt is not substantially different to the last one.

Personally, in this day and age I have little time for the concept of Class A. I recently had a pair of Class A monoblocks in my system. While they sounded really rather good, the concept of wasting so much energy is anathema to me.

 

[PsB]

Markus,
I respect your thoughts on Class A, but I live in Northern Europe, where the home has to be heated most of the time. Whether it is heated by radiators (equipped with suitable thermostats of course) or by a class A amp is pretty irrelevant, both to me and in the broader scheme of things. I am outside most of the time during the (short) summer so the system gets used pretty rarely from June to Sept.

(I think people promoting energy saving (neon) bulbs in N. Europe are barking up the wrong tree for the same reason. I just took another load of those rubbish bulbs to the recycling centre yesterday. I hope the mercury, electronics and other rubbish in them will be re-cycled into something useful, but the cost is high for a questionable benefit. We was conned. But I digress.)

 

[Steven Toy]

I knew you would say that ST and that is one of the reasons I posted (it). The other is that I firmly disbelieve all of the crap you come out with including the idea that leaving something on is worthwhile. JMO of course and I (try to) respect yours.

Disbelief is another form of belief.

I accept that for some sound quality is lower down the list of priorities. The same will no doubt consider getting the best from their equipment to be overrated or even pointless.

Well they would, wouldn't they?

 

[Elephantears]

I've just experimented with the Croft Series 7 amps and the regulated version, the 7R, seems much more powerful; meaning it has a much greater ability to handle dynamic transients. And also the sound is even richer and weightier. Both are 50W.

So is regulation as important as sheer wattage in a power amp?

 

[Steven Toy]

Markus,
I respect your thoughts on Class A, but I live in Northern Europe, where the home has to be heated most of the time. Whether it is heated by radiators (equipped with suitable thermostats of course) or by a class A amp is pretty irrelevant, both to me and in the broader scheme of things. I am outside most of the time during the (short) summer so the system gets used pretty rarely from June to Sept.

(I think people promoting energy saving (neon) bulbs in N. Europe are barking up the wrong tree for the same reason. I just took another load of those rubbish bulbs to the recycling centre yesterday. I hope the mercury, electronics and other rubbish in them will be re-cycled into something useful, but the cost is high for a questionable benefit. We was conned. But I digress.)

I hate the bloody things. They don't last anywhere near as long as the manufacturers claim, the light they give off is shit and they give off RFI as an added bonus.

NOS tungsten bulbs will go the same way as NOS valves.

 

[LOTUS HIFI]

650 per channel

 

[Tony L]

To those of you who say 'my system goes really loud so I don't need more power', that's not really the point. The reason to have more power is to keep everything clean at higher levels (not just constant levels but dynamic).

Agreed, but those of us who say that kind of thing tend to have the sort of speakers that can actually output say a 104db peak, and do so when fed only a small handful of watts. In fairness most speakers can't do that cleanly no matter how much you fling at them! To use my system as an example: I have 95db 15" Tannoys, a studio monitor capable of dangerously high levels without strain or stress, yet, based on my iPhone sound meter, my listening requirements average at around 75-80db with peaks into the early 90s, i.e. I'm not even flinging a watt at them! Therefore the 10 watts I have represents more available headroom than the typical audiophile with say a 100 watt amp and 85db speakers has to hand.

 

[Darth Vader]

As I understand it each doubling of amp power gives a theoretical 3db of level, e.g. I'd get 95db out of the Tannoys for 1 watt, 98db for 2 watts, 101db for 4 watts and 104 db for 8 watts. Given I'd not even want to be around 95 db peaks for long that equates to plenty of headroom. The thing I don't quite understand is why the Leak's 10 watts actually sound bigger and more powerful than the Quad's 45! Current delivery?

Well yeas and no Tone. Here are my sums based on assumptions:-

Sensitivity of speaker 95dB@1W@3ft

Therefore with two we get 95+3dB = 98dB@3ft

Room gain adds 4dB so that gives 98+4=102dB@3ft

Assuming you sit 6ft from speakers than you'll get 102-6dB = 96dB at the listening position for 1 watt. Not bad eh?

Now to cater for rock music you'll need to reach 120dB unclipped peaks -only short duration mind so thats an extra 24dB over 1 watt = 251watts!

Cheers,

DV

 

[Tony L]

Now to cater for rock music you'll need to reach 120dB unclipped peaks -only short duration mind so thats an extra 24dB over 1 watt = 251watts!

Not to cater for it the way I listen to it! There is no way I'd want to be in a room with a 120db peak! As I say my average is 75-80db, I consciously keep things safe as I want to preserve what's left of my ears as best I can.

 

[muzzer]

30+30 Class A into Audionote J

 

[Darth Vader]

Not to cater for it the way I listen to it! There is no way I'd want to be in a room with a 120db peak! As I say my average is 75-80db, I consciously keep things safe as I want to preserve what's left of my ears as best I can.

It really depends on what you want from a HiFi system.

Some people don't listen to loud music. They like background levels, and with average speakers, background levels demand 1 watt or less of amplifier power. Or like you they may have very efficient speakers (Klipsch, Cerwin-Vega, Tannoy, and the like) that will play extremely loud using modest amplifiers, the trade-off being a very large degradation in tonal accuracy, a definite harshness, and a complete loss of off-axis performance that accompanies horn-loaded designs.

All I can say is that with unclipped peaks (transients) my music is very clear and dynamic. With Naim 135s the sound was in comparison 'thick', 'heavy' undynamic and lost the timbre of unamplied instruments/voices.

BTW the same calculation for my 88dB sensitve speakers yields an ear splitting 5000watts!. Gawd I only have 1600watts per channel!

Cheers,

DV

 

[Barrymagrec]

It really depends on what you want from a HiFi system.

Some people don't listen to loud music. They like background levels, and with average speakers, background levels demand 1 watt or less of amplifier power. Or like you they may have very efficient speakers (Klipsch, Cerwin-Vega, Tannoy, and the like) that will play extremely loud using modest amplifiers, the trade-off being a very large degradation in tonal accuracy, a definite harshness, and a complete loss of off-axis performance that accompanies horn-loaded designs.

All I can say is that with unclipped peaks (transients) my music is very clear and dynamic. With Naim 135s the sound was in comparison 'thick', 'heavy' undynamic and lost the timbre of unamplied instruments/voices.

BTW the same calculation for my 88dB sensitve speakers yields an ear splitting 5000watts!. Gawd I only have 1600watts per channel!
Cheers,

DV

And neighbours some distance away, presumably...

 

[CB4]

80 per channel (monoblocs).

 

[Darth Vader]

And neighbours some distance away, presumably...

I think you have missed the point. Transients are very short lived but are what makes an instrument sound like an instrument. I use an SPL meter and my average/peak SPL is lower with these big amps than with the modded 135s but sound louder. BTW the SPL meters are unable to track fast and short lived transients and I lack the lab equipment to actually measure these figures. However the change in realism on going to more powerful amps really has to be heard.

Cheers,

DV

 

[Uzinusa]

NCC200s. 90W per side.

 

[bottleneck]

Quality has nothing to do with topology.. and everything to do with design IME.


Power is different.


...there are very real world reasons why valve amps don't have hundreds of watts.

 

[Tenson]

I really don't think many people listen at 120dB @ 6ft peak. Most speakers top out around 114dB @ 1m anyway.

Anyone who listens at 120dB is an idiot.

 

[mudlark]

god knows. NAP 140 to tweeters 45(?) and 80-90 to bass drivers, active.

 

[Barrymagrec]

I think you have missed the point. Transients are very short lived but are what makes an instrument sound like an instrument. I use an SPL meter and my average/peak SPL is lower with these big amps than with the modded 135s but sound louder. BTW the SPL meters are unable to track fast and short lived transients and I lack the lab equipment to actually measure these figures. However the change in realism on going to more powerful amps really has to be heard.

Cheers,

DV

I well understand the difference between a transient peak and average level. I have 90 watts per channel into 89dB speakers and have never approached maximum level, I prefer to listen to the music rather than vibrate ornaments off the mantlepiece but whatever is right for you is right for you.