Sokogear, there are several parameters you can look at besides frequency response, the various types of distortion, group delays, phase angles, etc. As I alluded to in my last post there are subtle changes you can measure but not hear. If you hear it it can easily be measured as modern test equipment is far more sensitive than any human ears including millercarbon's. I would also insist that if I hear a difference all of you can hear it also. The reason I know that timing is very important with subwoofers is because I can delay any of my speakers in increments of 0.1 msec. Sound travels at about 1 foot/msec (13.38 inches at sea level to be exact) Delaying a speaker 1 msec is like moving it a foot away from you. At about 2 msec you can hear bass volume and transient response start to decline worsening as you increase the delay until eventually you hear a distinct echo at about 30 msec. Delays of 15 msec create a "chorus" effect. When all the speakers are time aligned you get the best transient response and imaging. In the bass this means impact which is vital for producing the "you are there" sensation.
@chakster , in the lab? Cooking up toxic potions again? "Scully" by the way.
@lewm , you are so mean! The Fuzz Linear 700 sounded a whole lot better than the Crown 300. I owned one. It had it's benefits over the tube amps of the day. The power was intoxicating and the bass was much better. Yes, it was a bit brittle sounding up top but back then most of us did not know any better. Like most young males it was all about volume. People say they were unreliable but I beat the crap out of it for 8 years through high school, collage and into grad school and it did just fine. My next amps were the high voltage tube amps in the back of Acoustat X's, quite a leap.
The best turntables sound like nothing, nothing at a constant speed. The best turntables are the ones that isolate the cartridge from everything happening around it. The cartridge is a very sensitive vibration detection device. It could care less whether the vibration comes from the record or anything else. If the turntable has a sound it is coming from the "anything else," be it a resonance in the tonearm board or bass coming up through the plinth.
Just for fun I propose we all do an experiment. I can't do it myself as I do not currently have a turntable. Everyone can tell me what happens!
Place your stylus down on a record but do not turn the turntable on. Have your significant other hold their phone 12 inches away from the cartridge playing any song on the playlist. Turn your volume up all the way and put your ear right up to a speaker. Hear anything?