[wualta]

Quote:

Originally Posted by facelvega ps, the HP-50a are also very different from my other orthos in that they have far more bass than either of the others, which seems interesting in regard to the damping problem..

[earflaps fly upward, indicating interest]Did you say.. bass? The reason I find that interesting is that it's the difference in out-of-the-box sound between the Yama HP-1 and the YH-100, and it was the lousy-sounding YH-100 that turned out to have more potential. It needed a severe amount of damping, but the sound was so much improved that it's one of my favorite 'phones.

Am I correct in saying that the HP-50A sounds bassy (whompy-bassy, not tight-bassy), dull, hollow, nearly unlistenable? If so, they managed the extra bass by changing the compliance (and thus the natural resonant frequency) of the diaphragm-- thinner Mylar, shallower pleats, who knows. So put the HP-50A aside for futzing with later. Maybe we'll come back to it after you plumb the depths of AKG's mid-'70s obsession with 2-way everything.

 

[m8o]

Quote:

Originally Posted by Duggeh The Ergo 2 is a very different sounding headphone. Ive only had mine for a day or two now, but I will provide some extensive impressions on them here soon. I will say this now though. They are much better than the HF-1 and as my memory serves me, better than the HD-650.

Yes, my bad in not reading the product page thoroughly. I eagerly await your impressions on them still (if you can drag yourself away from the AMT that is...

)

 

[facelvega]

First let me report to Duggeh that I was a bit hard on the HP-50's above. They really do respond well to generous amplification. I just think there are better orthos out there. They only get beat by the Koss when I try to drive them portably. Nevertheless, I'm sure you'll ditch them pretty quickish. But don't give up on the orthos!

Quote:

Originally Posted by wualta [earflaps fly upward, indicating interest]Am I correct in saying that the HP-50A sounds bassy (whompy-bassy, not tight-bassy), dull, hollow, nearly unlistenable? If so, they managed the extra bass by changing the compliance (and thus the natural resonant frequency) of the diaphragm-- thinner Mylar, shallower pleats, who knows. So put the HP-50A aside for futzing with later.

I don't think I could describe the bass this way-- it's actually reasonably well-balanced with a leaning towards bass, and perfectly listenable as is IMO. Even with the smaller drivers, they can hit individual low notes that my PMB's can't manage (though it might be a backwave issue in the latter case), and even hit them as clearly as my K340's do. My problem with them is that I get a kind of enclosed feeling, and it's not just lack of soundstage, but I imagine simply the limitation of the drivers. Maybe I'll send them off to the international orthodynamic research foundation to see what they make of them.

 

[Duggeh]

Best bass I've ever heard from a headphone this small IMHO. However, yes they have a collapsed soundstage and have great difficulty in rendering instrument separation in complex music, or indeed, even in semi-complex music. They handled Eiffel 65 and Basshunter admirably, but disappointed with a treble that lacks the sparkle that I like.

I'm running them from the Ergo Amp 1 and have the AMT disconnected and the volume dial at 12 o'clock, so yes, they like a lot of juice. They also smell of old headphone, which im sure a rub with some Fabreeze will fix.

I shall not be letting them go as quickly as I insinuated, but probably wont keep them either, simply because they rest on my ears, and I much prefer circumnaural.

 

[wualta]

Unless Yama did something to these that they didn't do to the US-market Orthos, I'll go out on a limb and say that if you like the HP-50a bass now, you ain't heard nuffin yet.

One of the happiest bits of serendipity I've ever come across in audio is that damping an ortho/iso not only increases/tightens the bass but brings up the treble as well. Even so, they don't quite achieve the sparkle of good 'stats (assuming the source recording is putting out sparkles), although in the case of the T50 they're damn close, and the Yams are not far behind. So yeah, I'd like to give these li'l hummers a go. When you two have time, take 'em apart and let's peek inside. You don't have to remove the earpads to get at the five screws, just peel back the outer edge of the pad to expose the screwheads.

http://home.hccnet.nl/joop.nijenhuis...1/RHP1P039.jpg

 

[Duggeh]

Before.

Pad removal was impossible while preserving stickiness, you can also see here that there are no screws holding the frame together.

Spring clips (3 of) hold the plastic down inside the earcup. A bit of a twist with a knife and it popped right out.

The driver. 300ohms, 93dB/mW/ch, 2watts

The voice coil clearly visible through the holes.

Rear foam removal.

Continuing to listen to these, there is a complete inability to handle anythgin that soars, or any reverb or echo, Kate Bush on King Of The Mountain just sounds dead at some points where I know here shoudl be some echo. Sound is just a bit sucked out. Plucked strings die on the note instead of fading as gently as they should. These drivers are so small though. I recon I could easily hack them into some clip ons.

But that would just be wrong I tried them from my iPod, it takes 90-95% volume to get them driving and they sound thin, lacking all of the bass they have from a desktop amp.

 

[facelvega]

Wow, no felt, just foam. How the devil are these coughing up so much bass? Wualta, really, I've just tried mine again against a few other headphones, and the bass is remarkable and actually, pretty good. I completely concur with all of Duggeh's remarks about the sound. (edit-- I thought I did! Turns out he was actually hearing quite a different problem, see below) Could it be the backwave that's killing the highs? Damp, Duggeh, damp! Stick some felt or cotton in there to see if it helps the highs.

 

[Duggeh]

I dont have any felt or cotton wool, and how would sticking it in behind the driver help? Even if it helped the highs, I don't expect that it would help with the complete lack of timbre. These are fine headphones for a bit of pop music, especially given how bass light my main headphones are. Wouldn't having them opened up help more than closing in anyway?

 

[facelvega]

You need to talk to Wualta about this one. Evidently there's a basic problem with orthodynamics arising from the planar shape-- essentially they radiate a sound wave off the back which is identical to the front wave but precisely opposite in terms of vibrations, as it's coming from the reverse side of the same driver. When this wave bounces back from the inside of the casing, it cancels out the sound you're trying to produce. I don't know how this applies to other planars like electrostats. According to Wualta, damping dissipates this canceling wave, keeping it from interfering with the one that comes back to you. If he's right, then some of the limitations we hear in the highs might be the result of this backwave. But then why isn't it killing the bass too, as it tends to do with my other orthos? We need to hear from the man. But if you find some felt or cotton around the house in the meantime, you can test this while we're waiting to hear from him.

 

[Duggeh]

Haha!

I've been trying to get to the bottom of this damn suckout with certain songs and why theres this flatness to all the sound.

The headphones are terminated with a MONO plug

Time to break out the soldering iron I think!

sadly its not as simple as a jack replacement, the entire cord is 2 core. Itll need a whole recabling.

 

[m8o]

Quote:

Originally Posted by Duggeh Continuing to listen to these, there is a complete inability to handle anythgin that soars, or any reverb or echo, .... Sound is just a bit sucked out. Plucked strings die on the note instead of fading as gently as they should. ... I tried them from my iPod, it takes 90-95% volume to get them driving and they sound thin, lacking all of the bass they have from a desktop amp.

the downside of providing such candid and helpfull commintary is what head-fi'er is going to buy them from you now?

edit: I stand corrected. All that's because you were being fed a mono signal I see now?

 

[facelvega]

Quote:

Originally Posted by Duggeh Haha! I've been trying to get to the bottom of this damn suckout with certain songs and why theres this flatness to all the sound. The headphones are terminated with a MONO plug Time to break out the soldering iron I think!

That was the last thing I was expecting you to say. Wow. A later refit, I assume? OH, wait, I should tell you, my pair had some shorting problems inside the plug that caused some funky issues early on. I simply unscrewed the plastic cover and inserted tiny pieces of paper between the solder points to repair this. If it's the original plug and has the usual three-zone stereo format but is just acting like a mono, give this a try before warming up the soldering iron.

 

[Duggeh]

No its an actual mono jack, with 1 ring. It also doesnt unscrew, I had to cut it off. So until I do this recable, these headphones are out of action.

 

[wualta]

Wow, quite a Yamaha adventure! Facel, yours is stereo but Mr. Duggeh's is mono? I gotta go siddown.

It's worth pointing out the similarity in construction of the Yamaha's isodynamic driver and the Ergo's AMT: they're both "printed" aluminum voice coils stuck to polymer film, driven magnetically in what are hoped to be uniformly distributed magnetic fields, as opposed to the focused, concentrated field of a dynamic driver.

Oh, and great photos, Mr. Duggeh [now moved to the Orthodynamic Roundup thread]. Interesting construction on the HP-50A, too-- no screws! it snaps together! Nice and simple and cheap to assemble.

 

[wualta]

Quote:

Originally Posted by facelvega ...essentially they radiate a sound wave off the back which is identical to the front wave but precisely opposite in terms of vibrations.

Right. Just like Mr. Duggeh's AMT or Heil driver, iso drivers are inherently dipoles. Same thing out the front and the back but opposite polarity. If you could combine them, you'd hear nothing at all. You have to keep the bass component of the backwave from finding a shortcut into the earcup, and all the Yamaha Orthodynamics except the wacky YHD series did this just fine. Dynamic drivers generate backwaves too; they're usually not as strong as with a classic dipole, but manufacturers know they have to control them. If they don't, you get crazy variations in bass in production, as with the AKG K501. With the AMT you need all the bass you can get.

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