m17xr2b's Initial HD650 Mod - Quick Impressions and Measurements

Discussion in 'Headphone Measurements' started by Hands, Jan 28, 2020.

  1. Hands

    Hands Overzealous Auto Flusher - Measurbator

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    This is the HD650 mod by @m17xr2b, though it does not incorporate their latest experiments where they replaced the spider with a custom part. You can read more about that here. If ever that mod, supposedly the final one, comes through my door for listening and measurements, I'll make sure to properly update this thread.

    Nonetheless, I thought there may be benefit in getting a quick look at my thoughts and measurements, both for @m17xr2b's development purposes and for another reference point from those that may have already heard this pair or one like it.

    You can see @ChaChaRealSmooth's impressions for the same pair here.

    I won't beat around the bush on this one.

    I found them much, much too bright overall. And while the usual upper-bass through midrange color of the HD650 had been toned down, they sounded too lean overall. This exacerbated the upper end emphasis.

    Extension was poorer than a stock HD650, though this is to be expected with the more permeable baffle material around the driver.

    I think it's a bit too easy to mistake additional treble and/or less bass for a faster, clearer, or more detailed headphone. It may make bass sound tighter and more defined.

    Though perhaps there was some additional speed and low-end control over a stock HD650, it came at a severe price to tone. And I say that not in regards to just the HD650's best feature, it's mid-through-treble tone, but from a holistic scope that looks at it compared to headphones in general.

    Then again, I can't really say if there were any true performance gains. The brightness is extreme enough to overpower the senses in such a way that you can't really judge anything else properly, especially not in the context of how it compares to what it used to be.

    Unfortunately, not even high output impedances from amps and warm DACs could do much to help. The only way I found these mild-to-moderately listenable was at incredibly low volumes.

    So, here's to hoping the final mod turns out better.


    Mod (blue) vs stock HD6XX (red).

    HD650 m17xr2b Mod vs HD650 Frequency Response.png


    CSDs are fairly clean, especially for the amount of treble. And I didn't hear any ringing of note.

    HD650 m17xr2b Mod CSD.png

    HD650 m17xr2b Mod CSD 45dB Floor.png


    Distortion results left out because I was having consistency issues with accurate volume and may have saturated the mic at points. Not enough to cause any crazy results, but D2 was a bit higher overall in the midrange and treble than stock. Bass may have been a bit lower in distortion, but it's also being driven at a relatively lower level when targeting 1K @ 90dB compared to a stock HD650. Differences there, even still, were within margins of error.

    Either way, I'd like to err on the side of caution and not put out something that could be in error.
     

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