The AKG K500 was the more expensive bigger brother of the K400 with more luxurious looks and headband as well as a different colour scheme.
It has the familiar AKG look and is simple and elegant. The pads are cloth instead and very comfortable for longer listening sessions.NOTE: the spikes that are measured here MAY have been caused by the fact that it was tested at 95dB SPL, which may have been a bit too much for it.
This headphone does start to distort at higher listening levels much sooner than most other headphones.
While it did have an edge to it at normal listening levels (around 80dBA) it certainly did not sound as bad as the measurements would suggest.
The CSD shows a shorter lived ringing around 8kHz but also has a substantial ringing around 2.5kHz. The K500 also has a bright ‘edge’ resulting in a slight feeling of ‘extra detail’.
Deepfunk also had K601 pads which can easily replace the original pads. The K601 pads are velours type and feel a bit stiffer to the touch but still very comfortable. The picture below shows what a K601 padded K500 looks like. Together with the grey leather headband looks as if it could be an original combination.
AKG K500 with K601 pads sounds somewhat better in the bass area. It still lacks bass extension though and while slightly improving the treble quality (which isn’t bad but below that of better headphones) it still has a slightly artificial treble. Tonal balance is ‘accurate’ and very realistic.
The CSD of another of deepfunks K501's, however, shows a quite different behaviour. No resonances around 1kHz and no resonances around 2.5kHz and a much shorter lived 7kHz resonance. The 13khz resonance is still the same.
Because this K500 didn’t show the 2.5kHz resonance I figured the K601 pads would be responsible for this improvement in the 2.5kHz area.
Fitting new K601 pads on the other K500 showed it was a difference between drivers and not caused by the pads.
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The positives are a very neutral sound, no muddy-ness with good comfort. Sounds good with Jazz and classical.
Negatives are the lack of body (bass extension) and the slightly ‘artificial’ treble.
The K601 pads bring some improvements which are most noticeable in having slightly more body.
See this in a subtle light, as it remains a headphone that still lacks bass extension.