Released in the mid-80s, the HD540 (Reference 1, here a 600 Ohm model) was Sennheiser’s flagship and top of their open line. A lot of variants existed ; different variants of Reference 1 (300 Ohm, 600 Ohm, different headbands, pads), the HD540 Gold (basically a limited run HD540 with better matched drivers, gold housing and nice wooden box), and the HD540 Reference II.
The HD560 Ovation later came, followed by the HD580 Precision in 1993.
The HD540 is extremely comfortable and light (only 207g, and they’re not small), but feels as cheap as some $5 toys. The 600 Ohm model requires quite more voltage than an HD600. I would say it’s slighty harder to drive than an AKG K701, and similar to a 600 Ohm Beyer DT880.
○ Release : 1986
○ Current status : Discontinued
○ Type : Over-ear / Open-back
○ Measured weight : 207g
○ Impedance : 600 Ohms
○ Sensitivity : 94 dB/mW
○ Average used price : $80-100
As the HD540 I purchased came with stock fabric pads in average condition (but still not too worn), I did some pad rolling. With original fabric pads, they sound too thin to me – quite bright, lacking low-end and with hot mid-treble. They sound extremely open with a surprising stage (the HD600 is very narrow next to the HD540).
With simple pleather pads (from Ebay), they have more body and sound surprisingly good. Even great, for the price they go used. I really recommend doing some pad swapping if the stock fabric pads lost their rigidity. I like the Chinese pleather pads on them, as well as regular Brainwavz Round Pleather pads. The head-fi thread is very rich and lot of pad options have been covered.
They come close to an HD600, with 1-2dB less bass, but bigger soundstage and almost the same midrange tone – something really hard to achieve. The timbre with these pads beats 95% of the headphones I’ve tried. Treble is smooth, not too rolled off though lacking some top-end air past 10khz. The HD600 has a slight edge for microdynamics and overall resolution.
Cheap build, but solid durability like expected with these old Sennheiser drivers. Super light, extremely comfortable, open sound, a bit bass-light but excellent midrange and treble timbre. I would still recommend the HD580 over the HD540 since it’s a bit more resolving, better built and does not need any pad rolling + pads still available from Sennheiser.
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