I recently inherited a pair of 58X. First heard the headphone a couple years ago, friend had the 58X, 6XX, and 600 and I spent some time listening to them together. Came away with a strong preference for the 600, which I’ve since bought and loved. Between 6XX and 58X, as I recall, I had a hard time discerning much difference in frequency response, but found the 58X a bit warmer, and even moreso found the 58X a bit woolier slightly muddy.
Now I’ve got the 58X (via the same friend), which was useful reference in comparing with the new 560S. I like the 560S quite a bit better, largely because 560S has none of the midbassy bloom that clouds up the 58X. I figured I’d use the 58X as a reference, but not likely use for enjoyment. So when I found out about the mods described by DIY Audio Heaven, I was pretty interested.
I don’t have any felt on hand. I probably do have some furniture pads, but that FR change didn’t seem as appealing (based on DIY’s measurements). So taking some principles from the DIY experiments — more blockage = less bass — I experimented with what I do have on hand.
Started with some 3M micropore tape. The effect on reducing the bass is immediately obvious. Seemed to significantly clean up the mud. Listened a bit longer... OK, it removed all the bass
I am not one to complain about a lack of bass (#nobassgang), but the effect with micropore is too strong. It brings some space to the sound and cleaner definition between instruments — actual imaging! — but it feels a bit lifeless without the bass support.
So I tried another material I have: Aeropress coffee filters. Cut small circles 2 cm in diameter and affixed with small dabs of Blu Tack. There we go! Mid bass is reduced, but not eliminated. More importantly, the 58X’s sub-bass is retained. Midrange is allowed to breathe vs the stock sound. Treble gains some prominence. I haven’t spent a ton of time with it, but to my ear it sounds strictly better than the stock 58X. I miss nothing from the un-modded sound.
Is it an HD 600 now? Nah. 600 treble is still smoother, midrange richer and better textured. The Aeropress 58X sub-bass is better extended. For a $150 can, not a bad compromise.