Phosphor Bronze Strings

Phosphor bronze is an 92/8-ish copper-tin bronze (traces of phosphorus stabilize the alloy during winding) wound around a steel core, used for the wound bass and mid strings on an acoustic set; the top one or two strings ship as plain steel, same as an electric set. The alloy is chosen for acoustic tone, not magnetic pickup response — an acoustic string is sensed by the top’s vibration through the bridge and saddle, not a coil.

What it suits

Steel-string acoustic guitar. "80/20 bronze" is the other common acoustic alloy (brighter, more brittle-sounding as it ages); phosphor bronze trades a touch of that initial brightness for a warmer tone that holds longer before going dull.

How it ages

Bronze oxidizes visibly (a played string discolors and eventually goes dark) faster than nickel does, and that oxidation is audible as tone loss well before the string is at real risk of breaking. Coated phosphor-bronze sets exist specifically to slow this.

The same gauge, computed

At a 0.024" gauge, D3 on a 25.5" scale — every input held equal except the winding material — this site's tension table computes:

• Nickel-Wound: 15.76 lbs (7.15 kg)
• Phosphor Bronze: 16.95 lbs (7.69 kg) — this material

Computed from string-tension-data.js's unit-weight table — the same module the set solver and the hub's own tension calculator both read. No second formula.