Break in period

Atmasphere,

Shadorne, are you saying IOW that you hear changes but you attribute them to yourself rather than the gear?

Often yes. Depending on the last time I had a cold the changes can be significant. Most often it is the result of focusing on something specific or different in a familiar repeated track. I suspect we get very accustomed to sounds and have a pretty good sonic memory (for example an actor's voice is instantly recognizable on a cartoon)...so changing a component as significant as a speaker can be quite disconcerting for several weeks as memory adjusts to the new way it sounds (versus previous familiar sound).

For example, when I upgraded mains from ATC 20's to ATC 100's I actually had to make an adjustment to the reduction in harmonic distortion in the extreme LF at higher SPL levels. Initially, it was disconcerting to me that a great big box speaker seemed to have less bass (but incredible clarity & punch) compared to a modest sized bookshelf with already a lean bass sound (compared to most fare). On the face of it, I had become accustomed to more bass warmth or harmonic distortion of the little driver when it was driven hard at higher SPL. (This effect cannot have been break in as the 100's were already well used).

when I upgraded mains from ATC 20's to ATC 100's I actually had to make an adjustment to the reduction in harmonic distortion in the extreme LF at higher SPL levels.

ATC 100 have less harmonic distortion at LF at high SP levels than ATC 20? Really

Did you measure distortion levels and how do you know it is harmonic distortions?

Did you measure distortion levels and how do you know it is harmonic distortions?

I did not make measurements but harmonic distortion is quite easily recognized for its warmth, woody or resonant sound.

I doubt ATC would make a more expensive big box speaker used in studio mix and mastering with higher distortion at "loud" SPL levels as a modest ATC book shelf near-field.

I could be wrong though. Neither speaker sounded harsh ( telltale signs of excessive odd harmonics ) except at excessive SPL levels that were beyond rock concert levels.

All speakers introduce lots of distortion. Given similar quality in design/drivers, bigger speakers tend to play louder cleaner (a general rule for all speakers and not just ATC).

Pauly

Did you measure distortion levels and how do you know it is harmonic distortions

Actually there is -or used to be- some ATC measurements available s/where re, linear & nonlinear distortion on their models. Unfortunately haven't found it-sorry. I do remember seeing this though... if you're actually interested.

Gregm,

I have a very old pdf of a paper that Billy Woodman published which explains his driver construction philosophy. It includes plots of speaker distortion and discusses IMD distortion and the advatanges of active versus passive designs. Unfortunately, speaker distortion measurements are pretty sobering stuff - I doubt most audiophiles realize the relative amounts of distortion coming from speakers compared to the rest of their gear. (Certainly not those who spend $4 K on speaker cables and an amplfier and only $1 K on speakers.)