Shure 545L
A Unidyne III built to be worn, not just held — and the only member of the 545 family that gives up dual impedance to get there.
Overview
The 545L is the odd one out in Shure's 545 Series, and that's exactly what makes it interesting. Where the rest of the line runs dual impedance and hands you a detachable cable, the 545L is low impedance only, with a permanently attached 6.1-meter (20-foot) two-conductor shielded cable — a small-diameter run chosen so the mic can disappear into a lapel rather than sit on a stand. Shure's own catalog is blunt about the trade: the 545L is the sole model in the series that doesn't offer dual impedance, and the only one with an attached rather than detachable cable. Buyers who wanted the flexibility of the 545D or 545SD were told, in effect, to buy a 545D or 545SD.
What it keeps is the part that matters. The 545L carries the same Unidyne III acoustic design as its siblings, with response extending from 50 to 15,000 Hz and shaped for voice and instruments. The cartridge is shock-mounted, which Shure describes as minimizing handling and stand-borne noise — and in the lavalier role that's not marketing, it's the whole ballgame. A clip-on mic that transmits every rustle of a shirt collar is useless. The cardioid pattern does the other half of the work, rejecting side and rear pickup so a lectern or a noisy room doesn't swamp the voice.
That $70 figure held for years. Tape Recording (January 1969, p.107) still showed the 545L at $70.00, sitting alongside the standard 545 at $80.00 and the 546 at $135.00 — a useful reminder that the lavalier variant was the cheapest way into the 545 family, not a premium trim. The 545SD-CN with its on/off switch and detachable cable ran $127 in a later 1984 listing. Inflation and connector hardware account for some of that spread; the relative position — 545L as the value entry — did not change.
Shure's catalog copy is worth reading closely for what it reveals about intended use. The 545L is grouped with the gooseneck-mountable models (515SBG, 515SB-G18, 561, 562, 572G) and with the lavalier line, and the catalog notes it can be hand-held, mounted on desk and floor stands, or fitted to a flexible gooseneck. The lavalier assembly is a separate accessory, the A54L in plastic, and the mic ships with that assembly, a belt clip, and the attached cable. So the 545L is really a general-purpose dynamic that happens to be optimized for wearing — a distinction that matters for anyone buying one today expecting a dedicated lavalier.
The small-diameter cable that makes the 545L wearable is also the part most likely to be abused over decades of use. The cartridge itself is robust — the 545 Series was built to keep working under punishing conditions, per Shure — so the cable and accessories, not the element, are usually the deciding factor in whether a used 545L is a bargain or a project.
Where does it sit against its siblings? The 545D-LC and 545SD-LC give you dual impedance and a detachable cable in a 255-gram handheld body; the 545SH-LC adds a swivel mount at 425 grams. The 545L is heavier than the handheld variants at 354 grams net, and its value is entirely in the wearable configuration. Anyone who wants a 545 to put on a stand should buy one of the others. Anyone who wants a period-correct Unidyne III to clip to a collar — for stage, pulpit, or broadcast — is looking at the right mic, provided the cable has survived.
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