He may have meant that he found the Pro 30 incredibly bad! Some have. It's easy to overdamp it.
And that brings me to point out the modder's dead end that's all too quickly reached with simple mods on old chassis compared to the escape the Neo Orthos hold out to us, albeit for a hefty price: Eventually it happens to all of us-- you reach a point in the mod where if you go for tighter bass (and once you discover that bass can be both deep and tight, it's a marvelous, addictive thing) by damping just a smidge more. If you do, you start to push that flattened-but-still-present resonant hump up into the low treble, where it will dog your heels and make your audio life hellish. This is the existential pain of modding the old orthos, and if you've followed my advice and refused to pay crazy money for them, you won't notice it so much until you hear a 'phone that was designed properly from the beginning (and for a much higher market niche). This could be one of the modern 'stats or, walletdrainingly (because the used market has yet to develop), one of the Neo Orthos-- as long as we're restricting the discussion to planars, anyway. At that point you make the decision to accept the compromise you have, or throw money at the problem and escape to a compromise with lots more elbow room.
An unpretentious little fellow like the Pro 30 is hard to hate, but you can make it sound bad. The diy escape is to open the back, using stiff wire screen (such as used on microphone windscreens) to hold in the damping material.
(dammit waiting them is hard lol). My fingers are crossed.
I hope so too, we shall see.