Can amplifier speed and resolution be measured?

[Frank Dernie]

Take cone breakup, for example.

Always bad, how bad varies

 

[Soniclife]

Will the amplifiers in my car stereo sound faster if I drive faster? I'm so confused...

Depends if you are driving towards, or away from yourself .

 

[tomchr]

I think «speed» as perceived in room must be room-depending?

Probably... Maybe? Depends. What is "speed" in this context? Can anyone define it in a way that a majority of audiophiles would agree on?

Tom

 

[rebbiputzmaker]

Now, to @jonbon's question: Measuring the transient response is certainly a way to measure how fast the amp can respond to a changing input signal. How this correlates with the audiophile term "speed" or "fast" is anybody's guess. Mostly what I find with audiophile terms is that there's no agreement on what they mean. Some describe the same phenomenon using polar opposite terms. Take cone breakup, for example. For some, breakup is associated with precision (positive). For others, it's associated with fuzz or "fizzy highs" or harshness (negative). Who's right?

Tom

Interesting, where have you read cone breakup is a good thing?

 

[andreasmaaan]

Probably... Maybe? Depends. What is "speed" in this context? Can anyone define it in a way that a majority of audiophiles would agree on?

Tom

The only definition I can think of that could have any technical validity would be non-constant group delay.

I don’t suggest this is necessarily audible, but it’s at least measurable - and related to “speed”.

(Ofc it’s not something we tend to see to any significant degree in amplifiers.)

 

[Krunok]

The only definition I can think of that could have any technical validity would be non-constant group delay.

I don’t suggest this is necessarily audible, but it’s at least measurable - and related to “speed”.

(Ofc it’s not something we tend to see to any significant degree in amplifiers.)

Maybe rise time is another alternative?

 

[solderdude]

Risetime is only a technical description for amplifier speed (V/time) and seems to have no relation to the 'perceived speed' of amplifiers.

The problem with perceived 'speed' of amplifiers is that it does not seem to have any relation to any measurements and seems to be loosely used to describe something the 'reviewer' feels would be best described as 'speed'.

(At least that's what I think)

 

[Krunok]

Risetime is only a technical description for amplifier speed (V/time) and seems to have no relation to the 'perceived speed' of amplifiers.

The problem with perceived 'speed' of amplifiers is that it does not seem to have any relation to any measurements and seems to be loosely used to describe something the 'reviewer' feels would be best described as 'speed'.

(At least that's what I think)

I don't really think term "perceived speed" makes any sense. Maybe if it would be related to a speaker, but to amp..

 

[solderdude]

Indeed, could also be related to the recording(s) used ?

 

[Krunok]

Indeed, could also be related to the recording(s) used ?

I fully agree, that is indeed the most logical explanation.

 

[Shadrach]

I think what is mean't (so the topic remains relevant )



- is there may be a grey area where measurements contradict what is heard. The Art of Sound Forum ( Marco ) in the UK provides a
viewpoint on this grey area by saying at Post 5 https://theartofsound.net/forum/showthread.php?17-The-basics-of-Ethos

"We would gladly use science automatically as the benchmark to judge all things hi-fi, if we felt that it provided all the answers necessary. It would certainly be much easier having an 'undisputable reference' as one's basis for judgement. But it's the grey areas that bother us.

Quite clearly, science can't currently provide all the answers in audio, certainly as far as measuring how equipment and its associated ancillaries treats music signals, and ascertaining how humans process recorded musical information, via our ears and brain. Therefore grey areas exist because we are not robots, and so when listening to music, our brains aren't programmed to respond in a specific way to known audio measurement parameters... The fact is, we do not listen to music in the same way as scientific apparatus measures sound waves.

If such apparatus could measure how we as humans listen to and appreciate music, then measurements would be truly meaningful and embraced wholeheartedly by music enthusiasts and audiophiles alike. That is why audio/music enthusiasts, like those on AOS, will always trust their ears more than any scientific tests or measurements, because what can currently be measured scientifically just doesn't tell the whole story.

Until the day comes when tests and measurements unequivocally provide all the answers, we will happily continue using our discerning ears which for us are infinitely more accurate and reliable in ascertaining what really matters in hi-fi (and subsequently in our enjoyment of music), especially in those all-important grey areas... It's often the small details or 'grey areas' that make the most significant difference, and thus are ultimately of most significance!

Marco"

My viewpoint is that it is possible to strip the essence of music from a piece of equipment by using electronic circuit techniques that make audio amplification or for that matter also attenuation sterile - yet at the same time the equipment might measure very well. Perhaps there are key measurements that also detect sterility in circuitry?

I've found it's a lot easier to forget about music when talking about audio reproduction. There is no music; it's just electrical signals until it reaches the loudspeaker and then those signals get converted to pressure waves which may or may not represent music. It is hard to imagine that electronic equipment 'notices' that it is playing music rather than test tones or a recording of a jackhammer.
The subjectivist argument about equipment mucking up the music falls apart as soon as one realizes that the music doesn't actually exist.

 

[Blumlein 88]

Risetime is only a technical description for amplifier speed (V/time) and seems to have no relation to the 'perceived speed' of amplifiers.

The problem with perceived 'speed' of amplifiers is that it does not seem to have any relation to any measurements and seems to be loosely used to describe something the 'reviewer' feels would be best described as 'speed'.

(At least that's what I think)

Like an amp with ever so slightly weak low end might sound faster than one with the opposite contour.

Slew rate would be speed of amplification. It goes hand in hand with frequency response. Spectral amps were over a megahertz in bandwidth and something like 500 volts/microsecond on slew rate. They had a fast sound in the sense you didn't hear the amp. You didn't hear anything like the amp unable to respond quickly enough.

I would also say at least among other audiophiles I knew we had a consistent among ourselves concept of amplifier speed. Some amps sound dark and slow, some sound light and fast. Tube amps seem to sound anywhere from a bit slow to not slow. A Classe is an amp that seemed to have a slightly slow sound to me. But I never tried that blind so maybe it was related to mine being in the black rather than silver case.

 

[Krunok]

But I never tried that blind so maybe it was related to mine being in the black rather than silver case.

And which ones sounded "faster", black or silver?

 

[DonH56]

I gave up trying to figure out audiophile terminology years ago. I did notice the tendency to label tube amps "slow" and SS "fast" which I think is related to their damping factors/output impedance. Tubes often had "muddy" bass compared to the "tight" bass of SS amps, but then there is the whole "neutral be bad, sterile, bleh" and "warm be good, nice and fuzzy" and now "accurate" means "not an amp you should buy as it won't sound musical". Thank heaven for a Kal and a few reviewers that actually understand this stuff...

 

[Blumlein 88]

And which ones sounded "faster", black or silver?

Silver. Lighter brighter faster. Classe at the time came in both colors, but almost all I've seen were black.

 

[DonH56]

Just read (OK, started and passed by) another thread where rhodium is being blamed for bad sound so they are on a quest to get rid of rhodium anywhere in their connectors and cords. Apparently it's a pervasive evilness in most cables and connectors...

 

[Killingbeans]

Indeed, could also be related to the recording(s) used ?

Play some thrash metal, and if the amp stops and asks for a break, it qualifies as 'slow'

 

[tomchr]

I gave up trying to figure out audiophile terminology years ago. I did notice the tendency to label tube amps "slow" and SS "fast" which I think is related to their damping factors/output impedance. Tubes often had "muddy" bass compared to the "tight" abss of SS amps, but then there is the whole "neutral be bad, sterile, bleh" and "warm be good, nice and fuzzy" and now "accurate" means "not an amp you should buy as it won't sound musical".

"Musical". There's another trigger word. What does that even mean? I loved @Shadrach's description: No equipment in the recording chain or reproduction chain have knowledge of what's being produced. It's just electrical signals. Flows of electrons. Movement of air. The stereo image is an illusion created in your mind. Seriously! Think about it. There is no sound source between the speakers, but it sounds like there is. It's an auditory illusion - and a pretty good one too. The human brain never ceases to amaze me.

Slow, fast, engaging, sterile, etc. I wonder how much of that is honestly expectancy bias. "I am reviewing a tube amp, so I expect it to sound in a certain way". These unconscious biases are really hard to work around and anybody who claims to be unbiased is honestly fooling themselves.

Tom

 

[sergeauckland]

'Sterile' or 'clinical' are two words that get me going. In magazine reviews and on forums, they are almost universally thought of as a Bad Thing.

As someone who wants his audio to be clean, unsullied, blameless, I like 'sterile' and 'clinical'. The antonym of 'sterile' is septic!

S.

 

[Krunok]

Just read (OK, started and passed by) another thread where rhodium is being blamed for bad sound so they are on a quest to get rid of rhodium anywhere in their connectors and cords. Apparently it's a pervasive evilness in most cables and connectors...

Nope, it's not money, it's rhodium.