On avait parlé des differentes couleurs de bottlenecks et de leurs sonorites...j'ai pas retrouvé le post. Par contre, sur Diamond bottlenecks, y'a ca:
"I've read that different glass colors affect guitar tones - is this true? - Paul Oakey, United Kingdom.
It certainly is! The most noticeable difference is between the 'base' colors of clear (uncolored) bottle glass; green bottle glass; and cobalt blue bottle glass (these are the three most common glass colors used for authentic bottlenecks) - and this is particularly obvious on acoustic/resonator instruments. Clear bottle glass gives a warm, smooth tone - albeit with less volume than the other available color choices.
Green bottle glass is colored using iron-oxides, giving an excellent 'all-round' tone with more of a tonal 'bite' and warmer sustain than clear bottle glass, and with a noticeably slight rise in volume level due to the harder properties in the molecular structure of the glass.
Cobalt blue bottle glass is the hardest of all commercially available bottle glass, using cobalt oxide to provide the blue hue. Cobalt blue bottle glass gives the loudest volume of the three 'base' colors - and the tone is best described as 'spiky', seeming less warm & smooth in pure tone to the player.
The subtle shading differences of each bottle glass color can alter your tone very slightly - but not so noticeably as between the three different 'base' colors listed above, and occasionally brown. Brown bottle glass is more commonly used in beer bottling over here in Europe, and beer bottles have quite thin walls which are fine for 'high-octane' electric slide duties - but not so hot on acoustic/resonator instruments."