Do all the modern ETD's basically work the same way? In other words, is the end result going to be similar for every machine, all parameters being equal?

I understand you can tweak the settings to achieve the desired results, but what I am curious about is the differences in each ETD towards the end result, which is a beautiful sounding tuning. Of course, it's somewhat subjective as to what is a 'beautiful sounding tuning;.

The only 'test' I have ever done was between the Stopper's OnlyPure program and the RCT. The Stopper program cannot be tweaked.

I have however tried my Ipad2/Verituner with Bill's EBVT III 88 note presets for my piano, along with the RCT and Tunelab. For some reason, the Verituner achieved a better sounding tuning than the other two. My pro-tuner also had the same result when he came to tune my piano with Bill's presets. He has the original Verituner box.

Greetings,
The ETD's I am familiar with all produce broadcast quality results. I like the SAT, but the Veri-folks can do some serious analysis as they tune, as well. There are others, but they are all just tools.
Equality, beyond the ears' ability to detect, can be achieved by almost any of the modern machines. The appropriate stretch for the piano's intended use can be determined by ear, measured, and stored. Or, the stretch can be preset in the original sample notes, and the piano's natural curve bent to obey a theoretical result. They all can sound good, but cultured ears, when pressed, can sense a difference. Perhaps the aggressive stretch most suited for concerto work would do some injury to Mozart's chamber music, or the sharpened bass of the recording studios might cause Beethoven's more stentorian passages some weakness. A certain jazz artist I know likes so much stretch I asked him if he had played an octave lately...

The beauty of the machines is that they can measure and store all this information. They can allow the comparison of different amounts of stretch,(and temperament), with solid data on exactly what we are listening to. Or, when we find something we like, the machines can document it for future replication, consideration, or refinement.
They just cannot be trusted to tune a unison.
Regards,

Hi Ed,

Thanks for your great insights.

There is one ETD that actually can tune the unisons really well...that is Bernard Stopper's Tunic OnlyPure system. I have tested it many times, and it is always spot on. However, there is no way to store tunings and change the stretch etc,

Yes! I have Tunic also and when I get stuck on a unison I'll tune each string individually and it's right on or at least sounds as good as it's going to get. It's amazing.

I think they all aim at similar results. The differences are ease of use and the machines ability to measure accurately. I can remember an early SAT that, when in stretch mode, would accurately measure an octave, but would give wild readings when measuring a sharp or flat pitch.