[facelvega]

excellent news, Vaughn. By the way, if you want to get back some of that bass response, try covering all the vents out the back and sides of the earpiece with felt, and maybe use some blue tak to seal the driver to the baffle. These are the key places for tuning bass: you have to kill the bass-canceling backwave. Other than this, a slightly less-dense felt up against the driver will also help, but at the cost of a little of that resolution you just achieved.

edit: wow, we've reached page 100.

 

[wualta]

What ericj and facelvega said.

As shown in Yamaha's own graph for their SOTA model, the YH-1000, the top end slopes down from about 1kHz up:

Note that the YH-1000 driver is unique among Orthodynamics-- it was factory damped (albeit lightly). So the other Orthos may not have the same curve. My point was to show that even at its very best, Yamaha couldn't deliver flat response in the top octaves.

That's what the 3/4" sticker applied directly to the back of the driver is designed to correct. But this assumes that you've achieved more or less flat response from the bass through the midrange with Stage One. If you're hearing less bass than before modding, you may have overdamped. Slight overdamping gives marvelous transient response, but it's no fun to have lite bass. So you can use a cheaper more porous felt, yank out the paper discs, whatever it takes to get a response that sounds balanced from bass through the midrange. Either that or resign yourself to using EQ from your preamp/DAP. Overdamped bass restored to flat response by good EQ can be mindblowing. Bass is suddenly fun and dangerous again.

But not everyone has good EQ or the current-delivering ability to make it happen in the bass. So the middle path would be to adjust your damping until the bass is still tight but is, if anything, louder than before-- louder because tighter, better-controlled.

Keep in mind that the HP/YH-1 is not a bass monster headphone. It can be very satisfying, but if you need really deep bass, you need something like the now-rare YH-100 or the even rarer HP/YH-3, both of which contains a driver tuned roughly an octave lower than the HP/YH-1. The humble Realistic Pro 30 has a good solid low end as well, and it's easy to work on.

Another hint: shine a bright flashlight into the vents and make sure they're completely covered by the little strips of black felt and haven't been accidentally pushed aside.

Let us know how it turns out, maybe take a few pictures.

.

 

[Vaughn]

thank you all for your suggestions!

I think I will try the sticker mod next and see where that takes me.

I am using a 5.5g Ipod as a source and a MH Max as an amp. The equalizer
in Itunes is pathetic but I understand I can switch to Rockbox, which is supposed to be much better. Perhaps I can tune the bass response with this
and not give up any of the razor sharp transient response I have achieved.

I will try to post some pictures of my progress.

So now that I am fully infected with the orthodynamic bug, what is the holy grail? The YH-100?

 

[ericj]

The Holy Grail is the original 1978 version of the Fostex T50. Like most holy grails, they are exceedingly rare. They show up on ebay about 1.3 times a year.

Fostex currently markets a headphone that they call a T50, but it's really T20v3 with slightly different venting and gold plating on the metal parts. Everyone says that although it was obviously designed for some particular studio task that it's probably good at, for musical enjoyment it's a horrible disappointment.

Our White Whale is the YH-1000. They show up on ebay every 3-5 months and always mysteriously disappear within a day or so of appearing. Nobody we know owns one. Or wait, did wualta say he knows a genuine Ahab?

The YH-100 has oodles of potential for sure. Certainly one to look for.

You'll also like what we refer to as v2 of the Fostex T20. Really great bass potential.

Fostex identification can be tricky. The v2 of the T20 is black with off-white printing, and no red printing anywhere on it. v3 has a red stripe on the earcup - you don't want it.

v1 of the T20 is fun too, but not as bassy. You'll recognize it by the silver trim ring.

 

[wualta]

Quote:

Originally Posted by Vaughn Perhaps I can tune the bass response with this and not give up any of the razor sharp transient response I have achieved.

I like your idea of keeping them as an "EQ phone"-- keep the sharp transients and prop the bass up with EQ. Since the bass will also be razor sharp, boosting it will give you smacktile bass, assuming your amp can supply enough instantaneous current to feed the beast. These 'phones are 30 years old and use magnets that weren't state of the art even back then. Efficiency is their weak point. So don't even think of judging the bass capability of an Ortho unless you're plugged into something that can put out ~10 real watts from 20Hz -- 20kHz, if only momentarily.

Some of the non-Yamaha planars (Fostex, Realistic Pro 30, Audio-Technica ATH-2) and the later YHD-series Yamahas have much higher efficiency but are still power hungry by today's standards.

The original 1978 Fostex T50 is a great 'phone, but with mods the YH-100 can approach and in some respects (eg, bass) surpass it. Trouble is, both are or have become so rare that you can't be confident of putting your hands on one in the next 6 months to a year. Put them on your list, but also watch for:

The Fostex T20 version 2 (T20v2) is relatively plentiful on the online auction market, well-built and takes modding very well.

The Realistic Pro 30 is less plentiful and not as outrageously cheap as it was (currently ~$15 and up) but capable of wonderful results, and we have a few brave folks who've taken it all the way to Stage Two (flat response well into electrostat territory, with semi-open backs for max soundstage). Ericj just won himself an NIB example and I'll bet he's got plans for it.

Oh-- known (to me) YH-1000 owners: Tomek W. in Poland. Brewdog52 also has one and helped us do a transient response test. Steve T. (swt61) used to have one.

.

 

[spritzer]

I want to chime in and sing the Fostex T50 Mk1 praise. It really is a wonderful headphone, well balanced and neutral though I guess I'm in the minority since I like no damping at all.

 

[ericj]

Quote:

Originally Posted by spritzer /img/forum/go_quote.gif It really is a wonderful headphone, well balanced and neutral though I guess I'm in the minority since I like no damping at all.

Well, no damping is fine when the diaphragm is big enough and just loose enough but no looser.

 

[spritzer]

Quote:

Originally Posted by ericj /img/forum/go_quote.gif Well, no damping is fine when the diaphragm is big enough and just loose enough but no looser.

True. I really need to build a nice tube amp for them though even if they are my only headphone that doesn't need HV to function.

 

[facelvega]

Quote:

Originally Posted by ericj /img/forum/go_quote.gif Well, no damping is fine when the diaphragm is big enough and just loose enough but no looser.

Yeah, all our damping efforts are to make up for the fact that other orthos are not the T50. But yes, spritzer, you really ought to head in the tube amp direction with the Fostex. I've really been enjoying the synergy of my YH-100 with my little tube amp-- the smoothness of tubes goes well with ortho crispness.

 

[Vaughn]

I have found that my DV 336i does mate well with the HP-1's.

It seems that the enclosure on the HP-1 is really the achilles heel.

I wonder how many of you have made different enclosures rather than
trying to fix the existing one.

The stock enclosure appears to basically be like an aperiodic speaker cabinet.

I am thinking that the back wave could be absorbed/diffused into something like small anechoic chamber, which is allowed to leak (like the aperiodic cabinet) in a controlled fashion.
I realize this what is essentially being done with the mod, but it seems that
there could be a more effective way.

 

[wualta]

Quote:

Originally Posted by Vaughn It seems that the enclosure on the HP-1 is really the achilles heel.

It could be worse, but yeah.

Quote:

Originally Posted by Vaughn I wonder how many of you have made different enclosures rather than trying to fix the existing one.

Several have, notably member swt61's Chocolate Donuts (with an HP-1 driver) and the Strawberry Donuts (YH-100 driver).

Quote:

Originally Posted by Vaughn The stock enclosure appears to basically be like an aperiodic speaker cabinet.

This is one of those yes-buts. Yes, back pressure is similarly relieved, but in the headphone the backwave is mostly thrown away, whereas the output of a resistive vent adds to the forward radiation of an aperiodic loudspeaker.

Quote:

Originally Posted by Vaughn I am thinking that the back wave could be absorbed/diffused into something like a small anechoic chamber, which is allowed to leak (like the aperiodic cabinet) in a controlled fashion.

You're starting to think along the same lines AKG did when they invented the K240 Sextett. I should point out that to be able to absorb an appreciable amount of bass (ie, make the enclosure anechoic at low frequencies), you'd need a very large earcup indeed-- or how about this: you could have flexible ducts leading to a backpack full of fiberglass-- but it's easier to simply delay it and release it. The midrange and treble backwave won't harm anything and can contribute to widened headstage, so if anything we'd like to keep them. In fact the reflex dot uses the treble backwave to reinforce the characteristic drooping treble.

Quote:

Originally Posted by Vaughn I realize this what is essentially being done with the mod, but it seems that there could be a more effective way.

Sure, though only you can judge whether the effort involved would be proportionate to the benefits. A "tight" diaphragm, one that's tuned high (or highish) like the HP-1's and the T50's, can be put into an open-back enclosure with light damping or even no damping, but bass will be audibly limited compared to a low-tuned diaphragm whose necessary damping will give bass but take away headstage. It's a tradeoff. If you like razorblade transients, you'll need some mechanical damping no matter how the diaphragm is tuned, and that means you won't have to bother with an open-back enclosure, but ideally the driver cup volume should be absorptive and not reflect backwave into the driver.

.

 

[JadeEast]

Looking at one of the AKG patents for ortho headphones.
Closed earphone construction - Google Patents

Looks like an interesting idea using air mass to dampen the driver leave it to AKG to come up with a complicated way to damp a back wave. Looks like they had plans for an Ortho, they have a few patents taken out for designs around Ortho designs. I wonder what happend?

 

[wualta]

Thanks for finding that. I'll be studying it.

 

[Vaughn]

Ok, I reworked the mods on the HP-1's.

I had previously used a very heavy piece of watercolor paper in the stack
EricJ suggested. I found that the sound had actually become too sharp and sibilant with this in place.

I removed the paper disc from the stack replaced it with a canvas disc.
I cut out the center in each of the discs to reveal the metal cup which is
part of the pivoting assembly.
I then coupled the driver to the baffle with blu-tak. On the back of the driver I placed the 3/4" sticker. In the cup I placed a small marble size piece of blu-tak and pressed the baffle with driver into position. This (I hope) mechanically dampens the whole assembly.
The result is I have regained some of the bass but lost a small amount of the transient sharpness. I find the headphones, overall, to be much more
balanced.

I know this would all be much better with pictures, but until I learn how to attach them it will have to wait!

 

[wualta]

Posting photos is simple. Join one of the free online photo hosting sites like Image Shack or PhotoBucket. Upload your image files, then once they're stored on the host site, just copy and paste the resulting IMG files into your post.

I'd really like to see where you've cut holes in all the discs to reveal the pivot.


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