[sulcata_geo]

Quote:

Originally Posted by BigAmish /img/forum/go_quote.gif Funny, I looked at doing this last night when I took off my ear pads (inspired by the results with the K81DJ), but got scared off when I noticed that the foam disc seemed to be glued in place. Any suggestions as to clean foam disc removal? How easy were they to take off? Thanks!

Sponge rubber is glued by double-sided adhesive tape.
Carefully remove the foam,adhesion is not so hard.
Good luck!

 

[BigAmish]

Quote:

Originally Posted by sulcata_geo /img/forum/go_quote.gif Sponge rubber is glued by double-sided adhesive tape. Carefully remove the foam,adhesion is not so hard. Good luck!

Excellent. I'll try it & report my findings. Thanks!

 

[tbonner1]

Nice review Psiga. The treble smooths a bit after extensive burn in.

 

[BigAmish]

Hello everyone,

Just so you know, I posted the methods for modding the RP-21 as described by sulcata_geo in previous posts. It is an easy, reversible mod (so easy it may not have been worth the effort putting together detailed instructions) & I'd be happy to hear what the experienced Head-fiers w/RP-21s think about it. It, in my humble, subjective opinion, improves the upper-mids & highs quite nicely (similar to K81DJ & KSC75 mods). Bottom line: I like my RP-21s even more. Hope you do too. Thanks sulcata_geo!

You can find the link to the mod instructions here.

 

[Psiga]

Oh, nice. I peeked under the hood last night, saw that the foam was stuck rather securely, and just decided to leave well enough alone. I'm glad to hear that it's actually reversible! May take the plunge later -- it'd be nice to obviate this ~3dB slope on the paragraphic equalizer.

Thanks to both sulcata_geo and BigAmish.

 

[BigAmish]

Quote:

Originally Posted by Psiga /img/forum/go_quote.gif Oh, nice. I peeked under the hood last night, saw that the foam was stuck rather securely, and just decided to leave well enough alone. I'm glad to hear that it's actually reversible! May take the plunge later -- it'd be nice to obviate this ~3dB slope on the paragraphic equalizer. Thanks to both sulcata_geo and BigAmish.

Your welcome! In a worst case scenario, a few drops of Elmer's glue is all you need to reverse the mod if the highs end up being too bright for you. Also, were you surprised at how thick the foam disc was? It seems that one may be able to cut a thinner circle of open cell foam (purchased as a sheet from a craft shop) to replace the original if an 'exposed' driver is not an appealing option.

 

[Psiga]

It really is interesting. They are curiously thick. If our Equation friend is still reading the thread (hello! happy customer!), maybe he can tell us why they are so thick.

I was born in the briar patch, so to speak, with the KSC-75s... Not saying that I want to go back to that much treble emphasis, but seriously the RP-21s are problematic up there. If I can't listen to an empassioned vocal and feel tingly, then there's something wrong.

Okay, doing the mod...

Was first worried about how long the glue ring went on that foam disk, and about exposing the driver, but seeing your photos was a relief. Yeah, these are coming off pretty easily. Between the thin layer of foam that's part of the earpads, and the sturdy plastic grill over the driver, I'm not worrying about damage anymore. The foam disk came off fully intact, and the ring has enough stickiness that I'll be able to re-adhere if necessary.

So far so good.

Listening with covered left and uncovered right. Stress-testing by going right for a couple tracks from Sarah McLachlan and Sigur Ross.

20 seconds into the Sarah McLachlan track, I am 100% sold and ready to dig out the one on the left. Yes.

Left pad out, and now listening to a bunch of things. Yeah, as far as I am concerned this is a unilateral improvement. Like, wow. Those pads are not going back in. The 'dry whiteness' of the treble is reduced, vocals are more compelling. I'm not noticing if it detracts from anything. Bass seems about as good as ever, though I'm paying less attention to it now that there are upper frequencies worth getting lost in. If anything, drums sound better now that the attacks have their proper amount of treble.

This is great for me. Thanks again to both of you.

I'd really like to know why that pad is there, or at least so thick...

Bottom line: Do this if you're looking for livelier vocals and treble. You won't think that you're listening to a next-step-up headphone, but you'll think that you're hearing an RP-21 that works the way it's supposed to.

 

[BigAmish]

Quote:

Originally Posted by Psiga /img/forum/go_quote.gif This is great for me. Thanks again to both of you. I'd really like to know why that pad is there, or at least so thick... Bottom line: Do this if you're looking for livelier vocals and treble. You won't think that you're listening to a next-step-up headphone, but you'll think that you're hearing an RP-21 that works the way it's supposed to.

Very happy to be of service!

I'm quite pleased with the outcome as well (obviously). Also, you may want to put a quick link to your observations in the "Reversible RP-21 mod" thread for the benefit of anyone who missed it here. It is a nice overview of your experience with the mod & I wouldn't want anyone to miss it!

 

[Psiga]

Exactly. I was thinking that a few minutes ago. I'll do so in just a moment.

 

[jamato8]

I tried it but don't think I like it. The sound is a bit bright and the mids not as smooth. I think the frequency response is messed with, which is often why foam or something else is used to balance out a driver with some designs.

 

[Psiga]

Since BigAmish and I are kinda intimate with the KSC-75s, I suppose our tolerance for brightness is granted. I can appreciate how it might distract others. Either way, the padding seems thicker than it ought to be.

As I tinker with filters to bring out the best of the new development, I am starting to hear what you mean about the mids. Didn't notice it at first, but they went from being very neutral to me to now a bit overly-present. I'll wildly theorize that it's reflection and possible resonance from the plastic chamber.

Ah well.

For me personally: Pads staying off.

 

[bindibadgi]

jamato8, was it all bad?

Perhaps this is a good test of whether you are a "treble head" or not.

It's a shame that the mids get changed like that. Maybe some thinner foam would help. I've got some RP-21s on their way to me so when I get them I might experiment with this.

 

[jamato8]

Well you may get more detail but in my opinion the sound becomes etched, which is the antithesis of what I enjoy in good sound reproduction. I find that the detail is more natural and the mids more correct with the foam in place. I do like the Beyerdynamic leather ear pads I have been using. The bass is more responsive and I like the general frequency response a little better but the stock pads really are fine.

 

[Psiga]

Hmm. I've been spending more hours playing with them post-mod. There will be a certain divergeance of reproduction on eachothers' ends, since we're probably listening to different sorts of music through different DACs with different amping.

On my end, I can confirm varying degrees of what you've heard with the mids and sharpening: The mids went from being basically transparent, to suddenly a little bit obnoxious. In trade, the upper-mids and highs become brighter and more articulate. As for the etching, on my end it sounds sharper and more engaging, yet I wouldn't go so far as to say etched.

What I will say, though, is that bringing the upper-mids and highs forward has changed the balance that made me remark over their studio appropriateness. The modded RP-21 sounds, to me, less technical than before, now more fun. They're suddenly more forgiving of pop music and YouTube -- which I honestly wouldn't have thought would be dictated by a couple pieces of foam, but that's what I'm hearing. I am being less critical of the musical environments that I'm listening to, now just flowing through lots of songs and letting them groove around in my head.

Honestly, that's what I'm here for. But it's personal, so...! If anything, I guess it's sweet that the RP-21s are capable of going from technical'ish to fun'ish with a reversible mod.

 

[BigAmish]

Quote:

Originally Posted by Psiga /img/forum/go_quote.gif Since BigAmish and I are kinda intimate with the KSC-75s, I suppose our tolerance for brightness is granted. I can appreciate how it might distract others.

I definitely second this sentiment. I am a Grado/Alessandro/KSC75 sound junkie & I noticed that this mod pushes the treble/sharpness characteristics closer to what I prefer. This being said, that type of sound is not for everyone, especially since a number of head-fiers seemed quite content with the stock sound. This suggests the following as a possible compromise...

Quote:

Originally Posted by bindibadgi /img/forum/go_quote.gif Maybe some thinner foam would help. I've got some RP-21s on their way to me so when I get them I might experiment with this.

Although I don't have many sets of cans, I have some sets of cheap old foam earpads lying around made of thinner, more porous material. If I have time today I'll cut out discs of identical size to that of those that came with the RP-21s & install them. With luck they may enhance treble/sharpness over the stock config, but keep it more 'refined' for those who prefer that level of sonic balance.

Also, as a point of information, I have tested my RP-21s on my portable rig & home rig (see signature below), neither of which use any sort of headphone-specific amplication. That may, or may not, matter all things considered.

This is starting to remind me of the pad switching fun I had when I first started listening to my MS-1s!