"Fast amps" - really fast or a bogus marketing claim?

[Mike Lavigne]

Sorry, musical terminology for playing slightly ahead of the beat. It can be a mistake, or a technique. Keith Richards is rather famous for it. Sounds like it might have a similar meaning to the effect you're talking about.

So you're saying an amp that's too fast can actually cause a part of the music/signal to play a bit too soon, accentuating the leading edge of the note? But the entire signal is not played too soon, (which would make it all arrive together, and early or late we wouldn't know the difference), just specific notes? And this phenomenon effects the rest of the note? So the note that arrives too early decays too soon too, ie: the whole note is not present? I've also got to assume, then, that the early arrival and early decay are not equal, because if they were, that would just balance out.

Interesting, and a new one to me. Is there a name for this kind of distortion?

Tim

'expectation speed'...or...'bow wave' distortion.

if that phenomina is actually observed, i'll bet it's simply distortion in the initial musical note that smears the leading edge, and not any sort of actual 'ahead of time' thing. like a sort of 'stumble'.

 

[Johnny Vinyl]

Sorry, musical terminology for playing slightly ahead of the beat. It can be a mistake, or a technique. Keith Richards is rather famous for it. Sounds like it might have a similar meaning to the effect you're talking about.


Tim

Well, we all know Keith was slightly ahead of his time!

 

[LL21]

Sorry, musical terminology for playing slightly ahead of the beat. It can be a mistake, or a technique. Keith Richards is rather famous for it. Sounds like it might have a similar meaning to the effect you're talking about.

So you're saying an amp that's too fast can actually cause a part of the music/signal to play a bit too soon, accentuating the leading edge of the note? But the entire signal is not played too soon, (which would make it all arrive together, and early or late we wouldn't know the difference), just specific notes? And this phenomenon effects the rest of the note? So the note that arrives too early decays too soon too, ie: the whole note is not present? I've also got to assume, then, that the early arrival and early decay are not equal, because if they were, that would just balance out.

Interesting, and a new one to me. Is there a name for this kind of distortion?

Tim

Hi Tim,

I am not sure whether what i write below is what Keith is referring to...but here is my own thinking about where he (might) be coming from, based on my own experiences:

My observation of amps that are 'too fast'...is in fact not really about going faster than the signal...but about amps that try to give the impression of speed by accentuating leading edge...but in the end give you the feeling that the entire playback is too shallow...like there is no meat on the bones of the notes.

The audio system playback equivalent of when someone rushes through a piece on the piano...your fingers fly so fast, you have no ability to really press down into the keyboard and strike a convincing, solid, sonorous note...instead, your fingers fly across the top of the keyboard, you get each key pressed halfway down and you're onto the next note.

Now, i aint no techie...but that is sometimes how i feel about certain amps that 'seem fast' but in reality feel thin, hollow...a 'truly fast amp' in my book should be able to deliver the note transparently and fully, treble or bass, by controlling the amp (tweeter or woofer)...and getting the signal, the entire signal thru in balanced fashion. Some amps give the ability to really hear each note in the mids on simple pieces...but put on complex orchestral...and the lack of control means it all blends into mush or just feels bogged down from lack of control. it feels plodding, like the amp is struggling to keep up with controlling the speaker well enough to deliver the complex orchestral with individual instruments, synchopated rhythms, etc.

my observations.

 

[KeithR]

Lloyd- that is exactly what I think.

In general, since I bought 101db efficient, crossoverless speakers---my ideas on amplification have changed. I have had probably 15 amps in for demo of all types of topologies, so quite a bit of experience in this area. Amp matching has never been so difficult.

 

[Phelonious Ponk]

My observation of amps that are 'too fast'...is in fact not really about going faster than the signal...but about amps that try to give the impression of speed by accentuating leading edge...but in the end give you the feeling that the entire playback is too shallow...like there is no meat on the bones of the notes.

I've heard this in a lot of (usually) inexpensive studio monitors. There is an emphasis on the upper mids that hits hard at the transient attacks, especially in active systems, which have a very substantive kind of "fast." The whole note is there, though I can understand how over-emphasizing the attack could seem to diminish what follows. This can even sound good at first, but, like any contrived effect, it quickly becomes tiring.

Remove the crossover from between the amplifier and the driver and you get much more direct, much better driver control. It makes sense that this would reveal weaknesses in the amplification or mismatches between the amps and the speakers.

Tim

 

[LL21]

Remove the crossover from between the amplifier and the driver and you get much more direct, much better driver control. It makes sense that this would reveal weaknesses in the amplification or mismatches between the amps and the speakers.

Tim

Hi Tim,

when you say remove the crossover btwn amp and driver...do you mean essentially active speakers? Some speaker manufacturers 'calibrate' the cable between amp and speaker based on impedance...is this really possible given that a speaker (particularly with more than one driver) is multiple impedances across various levels across the frequency spectrum? or is it just marketing? (In truth, i love Transparent Audio cables...and just traded in the last bit of old equipment i had for an, in effect, 'free upgrade' to XLMM2 speaker cables which were calibrated for my amp and speakers. They are truly stunning, having just passed the 200 hour mark as recommended by TA.)

 

[Phelonious Ponk]

Hi Tim,

when you say remove the crossover btwn amp and driver...do you mean essentially active speakers? Some speaker manufacturers 'calibrate' the cable between amp and speaker based on impedance...is this really possible given that a speaker (particularly with more than one driver) is multiple impedances across various levels across the frequency spectrum? or is it just marketing? (In truth, i love Transparent Audio cables...and just traded in the last bit of old equipment i had for an, in effect, 'free upgrade' to XLMM2 speaker cables which were calibrated for my amp and speakers. They are truly stunning, having just passed the 200 hour mark as recommended by TA.)

Lloyd, I mean actives, or speaker designed with "full range" drivers, which, within their limitations, can be pretty impressive.

I can't imagine how "calibrated cables" really work, so I can't really comment.

Tim

 

[Gregadd]

Removing the crossover solves some problems but creates others. You don't want each driver running full range?

 

[DonH50]

Active crossover before the amps... Allows much better driver control, and DSP systems (or even analog units) allow tailoring crossover frequencies and slopes to optimize the response. Assuming you can do better than the speaker designer, of course... In some cases, passive crossovers require compromises that can be mitigated with an active design.

HTH - Don