List : Components with high dynamics

To these ears, good dynamics don't translate into high sound pressure levels. I primarily listen to classical music and excellent dynamics were a major quest for my particular system. Dynamics come in all stripes, the proper presentation of which is a major factor on the enjoyment of music. I've been to pop concerts that was ear-bleeding loud but had no or very little contrasts dynamically. Drum whacks were the same loudness as screaming guitar. I have listened to many amps, but I never thought that Krell - although high powered, did very much in the dynamics department. I discovered that a change in power cord greatly increased my amp to deliver wide and subtle dynamic swings.

In order to understand what is happening with dynamics in audio, it is useful to understand some of the rules of human hearing, in this case, the ear's use of odd ordered harmonic content as loudness cues and the masking principle.

Dynamic contrasts are thus artificially manipulated by amplifier and preamplifiers that employ loop negative feedback, but also those without. Amplifiers that have no loop feedback nor any method of reducing distortion (especially at higher power) will actually **appear** to demonstrate a lot more dynamic qualities than the amplifier would otherwise seem capable of. A good example of this is a 300b SET, that appears to be very dynamic for the amount of power it makes.

The issue here is that the ear uses odd-ordered harmonics as loudness cues.

In the case of the 300b amp above, the power and consequently the distortion is much higher on the transient peaks than the in-between areas. Most of the distortion is even-ordered as it exists in higher quantities than the odd-orders, but the odd-orders are there too, masked by the presence of the even orders. Despite the ear's masking aspect, the odd orders still trigger the loudness cue response, so the result is that the loudness cues are tied directly to the dynamic peaks in the music. The result is the **appearance** of a dynamic amplifier. But what is really happening is that in this case, the word 'dynamics' can be safely replaced by the word 'distortion' without changing the description of the amp's sound.

This phenomena is far too common in high end audio and IMO/IME is not by any means limited to SETs, although SETs do exploit this phenomena more than others. Oddly enough, amps with loop negative feedback will display a similar quality, but unlike SETs will lack the lush quality offered by the even-ordered harmonic content.

Consequently, I am always suspicious when audiophiles talk about 'dynamics'; I find that nine times out of ten they really mean 'distortion'.

One way to ascertain whether or not this is an issue is your system is to turn up the volume until you have to yell at someone sitting right beside you in order to be heard. The question then is: did it surprise you that the system was playing that loud? or was it unpleasant to play it that loud? Latter=distortion (plenty of loudness cues) Former=lack of distortion (very few added loudness cues)

Once this issue is settled then it is possible to delve into the issues of real dynamics; to avoid confusion I use the word 'impact'.

Jeff Rowland Design Group

Atmas said:

"One way to ascertain whether or not this is an issue is your system is to turn up the volume until you have to yell at someone sitting right beside you in order to be heard. The question then is: did it surprise you that the system was playing that loud? or was it unpleasant to play it that loud? Latter=distortion (plenty of loudness cues) Former=lack of distortion (very few added loudness cues)"

I think this is a very good test!

There's macro dynamics (big booms) and micro dynamics (the pluck on a guitar string). I get good dynamics (of both kinds) with my McCormack amp and relatively efficient speakers (@90db efficient).

But I have never heard dynamics (of both types) done better than with highly efficient speakers e.g. Klipshorns (105db efficiency). These are driven with 2 watt SET amps, which nobody would consider dynamic on anything less than Klipshorns. Of course they have other drawbacks that are not particularly suited to my tastes, but you can't fault them in the dynamics department.

So, my gut says that dynamcis are more of a function of the speaker efficiency than anything else, as long as there is an amp with sufficient headroom to drive them. However I don't think you would get the same result with a 1000 watt amp and 87db efficient speakers.

Enjoy,
Bob