Richard Clark $10,000 Amplifier Challenge - Why Couldn't Anyone Pass this Test??

@geoffkait  wrote: " Is A Stradivarius Violin Easier To Hear? Science Says Nope"

Maybe not to the average listener, but to a trained, professional violinist? Yes, absolutely! 

Many years ago I worked at the Banff Centre, which is where professional artists, musicians, & conductors go to hone their skills. Over the years, the Banff Centre has built up a sizeable collection of Steinway grand pianos (mainly through bequeathments). At last count (~2016), they had approx. 115 Steinways. Every Steinway had a name.

Musicians and conductors would be in residency at the Centre for anywhere from 3 weeks to 4 months. Some would specifically request their favourite Steinway by name.  

In 2004 I asked one of the piano techs (who have a contract with the Smithsonian in Washington to repair their Steinways) if someone could actually hear the difference between the pianos.

The tech told me that he did a blind sound test with Oscar Peterson in 1974. Oscar, who was the director of the new Jazz Program that summer, was being very picking in selecting a piano for the summer, so the tech arranged to have 20 pianos brought together onstage for Oscar to test. The tech blindfolded Oscar and then played each piano for him.

Oscar was able to correctly identify all 20 pianos by name, blind-folded. 

You obviously didn't read the article. They WERE trained musicians. That's the whole point. He-loo!

In fact I would love it if I could make the output impedance of our amps lower. The problem I have with solid state is that many semiconductors have a non-linear aspect about them that causes them to have higher ordered harmonics (at low levels, but as I pointed out earlier, the ear is very sensitive to that sort of thing) and hard clipping. The only devices that I have found that don’t are the static induction transistors made by Sony. IMO They had a chance to really set the audio world forward, but in true Sony fashion (which is to come up with an innovation and then shoot themselves in the foot) failed to make a full complement of driver and voltage amplifier devices to go with their rather amazing output devices.

Then when you add in high levels of feedback (there are various forms of feedback and I’m speaking in general terms), you end up with micro changes in transient values of the harmonic structure, all smeared out of time and out of level, shape, expression, and so on.

This is sometimes...the new detail found in some recordings. People mistake this false data as real and write the given amplifier up as being revealing.

Yet one good listen to the given amp by an aware person who has heard differently (and possibly understands what is going on), will drive said person from the given room with hands clamped on ears.

The brain and aural learning, generally moves forward. It is the cognitive speed and lack of aural projection (parallel aural paths in forms of known neural discernment and learning)..which makes the difference in this question and answer pairing (in it’s evolution). Ie, the brain has a masking and pre-load issue that it uses to keep aural experiences from taking too long to discern -it pastes in learned data on new and current aural experiences. Learning to defeat that mechanism takes time and awareness.

Or, for the intrepid audio explorer -"what has been heard, cannot be unheard".

Complex crossovers with low impedance considerations..exacerbate said issues, and make the given high feedback amplifier even more illiterate with fine transient function - and increase false harmonic structure. Which drives those who hear it, even faster.... from the given room. This falseness is, more importantly -- covering up real detail and real harmonics.

Using feedback in audio is tricky, at best.

This is cognitive function like learning and intelligence. It takes time to learn to discern these things, aurally. Some people ’get it’ sooner, some people ----never do.

Good thread. I appreciate this type of discussion because it provokes good technical insight as to speaker reaction due to various impedance variables and damping factors.
I have ZU Definition IV speakers driven by Macintosh MC60 amps. The impedance curve on the Defs are lowest at 50Hz to around 225Hz, being around 6 Ohms at the lowest, with a prolonged rise through the mids and treble.
Damping factor of the Macs is said to be 12.
What, if any, difference in frequency response of my speakers should I hear due to the varying impedance curve?
And just to throw something else out there, I recently purchased a quad of NOS TungSol 6550s that completely changed the bass characteristics of the speakers. The bass is softer but eminently more tuneful, with considerably more detail and nuance.

The complexity of the scenario is go great, that all you can do is try it and see if it works for you.

It's not quite random, but it is so complex that these scenarios really are individual in nature. The paring can be measured and listened to but fully fleshed out ahead of time and then take that and compare it to how your personal discernment and learned aural function relates? Not so much.

Generalizations like horseshoes and hand grenades (close is enough to get some sort of job done), is just about all that is predictable.