HD581 (prototype)

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published: Sept-15-2016

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NO SMOOTHING is applied to the shown plots. Most measurement sites have some smoothing applied which ‘irons flat’ sharp peaks and ‘wiggles’. I do not use smoothing because some info about sound quality is lost when plots are smoothed.

Aside from a small correction of the microphone itself also some correction in the lowest frequencies is applied to the plots to compensate for the perceived loss of bass when using headphones. This is described HERE in more detail.
A ‘horizontal‘ frequency response curve on the shown frequency response plots on this website thus indicates a perceived ‘flat’ tonal signature.

ALL measurements are made with a good SEAL on a flatbed measurement rig.
shape of your head, bone structure, pad size, pad ‘softness,  (compliance), hair or no hair and or wearing glasses may (drastically) change the frequency response of some headphones, so… your personal experience may differ substantially from these plots.

Frequency response (tonal balance) is the most sound-determining aspect of headphones. A horizontal line shows audible neutral response in the plots on this website. Deviations in different severities at different frequency bands have an effect on the sound character.
The bigger the deviation the stronger the effect.

Below an aid to help determining the sound character of headphones with relation to the frequency response.

sound descriptions mine

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Superlux HD581 (proto)


This is the latest model from Superlux (written in Sept 2016). The actual tested headphone is a pre-production model so the final version may differ from this one.
More extensive measurements and evaluation can be downloaded HERE

It has a full, yet clear sound signature. There is a slightly (but tasteful) elevated bass that doesn’t bleed into the mids. The mids have a good clarity.
The treble is not well extended so the headphone lacks the nice shimmer and small ‘details’ heard on hi-fi headphones. On some recordings it has a small ‘edge’ in the treble. Not sharp or sibilant sounding though.
It is clearly targeted to the portable market.

Below the frequency response of the HD581, left, right channel.


The plot shows the bass boost. As there is a small dip around 200Hz the bass does not ‘bleed’ into the mids. No warm and ‘fuzzy’ bass here but deep and clear sounding. I would say the best feature on this headphone.
There are clear mids that do not sound ‘warm’ nor ‘thin’ … just … accurate. The small dip between 2kHz and 6kHz takes away the ‘sharp’ edge in some recordings but also removes some clarity in certain instruments. Not a deal breaker in this case.
The treble has a small peak around 8kHz which can be audible as a ‘sharpish edge’ on some recordings. Fake and somewhat over pronounced ‘sparkle’.
The steep drop-off in output above 13kHz makes the treble less ‘Hi-Fi’ and is audible as being limited in the treble extension. Cymbals, strings etc. lack detail and ‘air’ when listening to it from a Hi-Fi perspective.
It is completely pointless to listen to hi-res recordings on this headphone. Having a frequency extension on the source above 15kHz is pointless. Anything better than 128kb/s MP3 won’t give more treble extension.
Those that like sparkly and extended treble (like I do) probably won’t be happy with it. Young people streaming crappy quality musing on their mobile phones may well be chuffed because of the bass.
That is IF they can get a good seal. This last part is where this headphone design is flawed.
More on this issue in THIS ARTICLE.

Below the distortion plot of the right channel.dist-hd581l

Bass distortion is elevated but not as bad as some other headphones. The peak at 4kHz is more worrying.

Below the CSD of the HD581. Left and Right superimposed.


What isn’t shown here is that the right channel doesn’t ring as much as the left channel at around 2kHz. The 4kHz distortion peak also is visible in the CSD. Aside from these resonances it doesn’t seem to have other problematic areas.

The Spectrum plot below shows resonances at 750Hz, 1.5kHz, 3kHz, 4kHz, 6kHz and 8kHz.


The squarewave response plots below (440Hz) shows that some of the resonances can be reduced by applying 1mm thick felt in front of the driver.
More on this in this article.

On the left side the square-wave and pulse response plots of the stock HD581, on the right the same driver but with 1mm thick felt in front of it.


These HD581 are NOT ‘Hi-Fi’ phones but do not sound poorly, they clearly lack refinement in the sound. The tonal balance is pleasant: Good tight bass levels, decent mids with good clarity but sometimes has an ‘etchy’ sound to it.
The treble is where it lacks. There is enough lower treble. It isn’t sibilant or ‘shouty’. Alas it also isn’t smooth, extended nor highly detailed. A bit boring in the treble.
They do sound better than the HD562 and HD572-SP. The first 2 are on-ear headphones where these will be (half) on ear to some and barely fitting over-ears to others.

These are intended for ‘urban’ usage on i-thingies and other phones/tablets while feeding poorer quality recordings.

NOT recommended for Hi-Fi usage. Well suited for listening to youtube quality streams and 128kb/s MP3.
Pointless to use with CD quality recordings and hi-res.

The negatives are:
Pads are on the small size of things so won’t fit everyone.
Adjustment in height and width is insufficient.
Getting a seal (essential for good sound) is difficult, simply because the cups are mounted very rigidly on the height adjustment sliders where they should be able to swivel at that point.

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