Sony ECR-500 - Overview
Sony used a pentagonally shaped monopole electret diaphragm (about 5 microns thick with roughly the same radiating area as a 50mm diameter driver) and sacrificed a bit of efficiency to space the stators far apart to give the diaphragm room to move (shades of the later Stax Pro electrostatics!); thus this headphone has more bass than even the contemporary Stax SR-X Mark 2 and 3, though it is not as flat and cannot play as loud. Minimal mechanical damping means the backwave of the '500 is unimpeded which gives the 'phones an openness that's ideal for listening to binaural recordings. An amazing headphone for the time (1976) and even for an electrostatic of the time.
General Description of the Sound
ECR-500 is a warm mid-centric sounding headphone with an excellent, detailed head-stage and natural tonal balance. Transient response is very good due to its large yet lightweight diaphragm. Unlike most electrostatic headphones from the mid-1970s, ECR-500 produces extended, deep bass that is at the same time well-defined and detailed. Detail retrieval is overall less than that of the best later non-electret electrostatics such as the SR-Lambda but is on a par with many good modern dynamic headphones.
The headphone's true strength is its ability to portray sounds that seem to originate outside the skull, in particular sounds recorded binaurally.
ECR-500's presentation is very smooth without any harshness or strain, and this, together with good comfort from the circumaural earpads, makes them very good for that relaxed late-night listing session.
Pricing & Other Data of Interest
ECR-500 was not very expensive when it was on the US market, about $150 in 1976.
Frequency characteristics: 20Hz - 20kHz
Sensitivity: 90dB SPL(adapter input 1 Vrms 300Hz)
Maximum sound pressure: 120dB SPL
Distortion: less than -50dB (adapter input 3 Vrms 1kHz)
Cord length: 2m
Weight: 350g (without cable)