[anticute]

  Well I've already spent a whole day trying new concoctions including extra butyl seal, circular cork board fence, cork board as dampening, etc. only to realise that Loyva's revision 1 was still the best, and that's what I'm aiming to get back to. So as long as you have exactly his rev. 1 formula, then you may have already taken this one to it's max - unless Loyva (Packdemon) has got somethin' up his sleeve yet...?
 
The above was done to remedy some worse than expected results from his custom revision 2 & 3 for my Tru-Fi mod, and we learned to not put butyl / dynamat on the driver or seal the bass too tightly.

With the bass ports completely closed, I felt that the bass had gotten a little bit too tame for my taste. With them open it was too much compared to the rest of the signature. A good compromise for me was opening the "real" bassport and adding a bit of "transparent" foam on the inside.

 

[DecentLevi]

Lyova & I spent a few solid hours last weekend revising the HP-100 and 150 mod and let me be the first to tell you, the results were SOLID... resolutely solid... on the HP-150 that is. We tried a series of small adjustments and I lent him my analytical hearing throughout, and the final result was that his newest revision of the HP-150 mod is a sure-shot winner! The newest HP-150 seemed around 30% better than the best we could get the HP-100. It was one of those very mysterious results of audio projects - although the only difference between the HP 100 and 150 is the earcups, and the mods used were identical between the two (at one point), the HP-150 sounded markedly better to my ears: improved clarity, bass definition and dynamics.
 
Anybody on the fence, now is your chance to get the first-class version of the Tru-Fi modded HP-150 from Lyova (@Packdemon). He's got what could be the last of the supplies coming in, and everything all set up! Enjoy!!! 

 
PS-  For anybody who's already got the Tru-Fi modded HP-150, I'd venture to say Lyova would be happy to assist you in converting it to the latest revision. There is 1-2 internal differences, plus an optional resistor adapter to add 75 ohms of impedance.

 

[Packdemon]

Lyova & I spent a few solid hours last weekend revising the HP-100 and 150 mod and let me be the first to tell you, the results were SOLID... resolutely solid... on the HP-150 that is. We tried a series of small adjustments and I lent him my analytical hearing throughout, and the final result was that his newest revision of the HP-150 mod is a sure-shot winner! The newest HP-150 seemed around 30% better than the best we could get the HP-100. It was one of those very mysterious results of audio projects - although the only difference between the HP 100 and 150 is the earcups, and the mods used were identical between the two (at one point), the HP-150 sounded markedly better to my ears: improved clarity, bass definition and dynamics.

Anybody on the fence, now is your chance to get the first-class version of the Tru-Fi modded HP-150 from Lyova (@Packdemon
). He's got what could be the last of the supplies coming in, and everything all set up! Enjoy!!! 

PS-  For anybody who's already got the Tru-Fi modded HP-150, I'd venture to say Lyova would be happy to assist you in converting it to the latest revision. There is 1-2 internal differences, plus an optional resistor adapter to add 75 ohms of impedance.

DecentLevi

The revision has not changed. The reason it sounds different this time was because the HP150 sounds better with the mod than the HP100 (though both are better than stock in terms of dynamics, THD ratings, comfort, and isolation). Also the impedance adapters help lessen driver imbalances (this was measured) while possibly having lower THD and better dynamics (not measured, only based on Levi's impression). What I did find out from taking measurements at the SF Meet, was that the portion of the mod kit that cleaned up (the distortion of) the bass was actually the dampening portion, not the sealing portion. This basically means that you can pick and choose how much bass (or inversely isolation) you want based on how open (or inversely sealed) you make the headphones without having to fear that making it too open might disproportionately distort the bass making it loose. I also figured out that 2 of the bass ports (the ones from inside the earcup hinside) on each side can be sealed from the outside without effecting the appearance of the headphones. That means that you won't have to constantly open up the headphones if you want to affect the levels of bass. I'll re-record the mod kit application tutorial to show how to do this fairly soon.

What Levi said was not entirely incorrect. The pair that I took the meet this time around did have more of the bass ports open, but again that was to test the bass distortion when having louder bass. The mod kit will still continue to have the same amount of materials inside, but I've basically confirmed that you can adjust the bass level (using less of the sealing materials) without ruining it's tightness disproportionately. By not disproportionately, I mean that while you still increase the distortion when you increase the volumes of bass (just like raising the volume, you increase all sound), but it (the distortion) will still be proportionately less than if you were to do the same thing (sealing vs opened) with the headphones undampened.

Best Regards,
Lyova Margaryan of Tru-Fi Speakers

 

[norepeat]

Ordered the mod kit from Etsy last night for my hp150, and see this latest post.   Great to hear hp150 response to the mod better than hp100.  From what I read, the mod is exactly the same between hp150 and 1st revision mod of hp100, right? 
 
For the impedance adapter, is it just measuring the difference between the right and left ear phone via DMM and add the difference in resistance to make them equal?  How come it's 75 Ohms?
 
Also, is there a new frequency response graph from hp150 that you can share?  Can you please also share the name of ear pad used for the measurement?
 
Will let you know once I get the mod kit and start modding my hp150....  I am very excited, thanks Lyova and DecentLevi

 

[anticute]

Just to clarify - there have been no major changes to the mod?

 

[Packdemon]

  Ordered the mod kit from Etsy last night for my hp150, and see this latest post.   Great to hear hp150 response to the mod better than hp100.  From what I read, the mod is exactly the same between hp150 and 1st revision mod of hp100, right? 
 
For the impedance adapter, is it just measuring the difference between the right and left ear phone via DMM and add the difference in resistance to make them equal?  How come it's 75 Ohms?
 
Also, is there a new frequency response graph from hp150 that you can share?  Can you please also share the name of ear pad used for the measurement?
 
Will let you know once I get the mod kit and start modding my hp150....  I am very excited, thanks Lyova and DecentLevi

Yes, that is correct.
 
Basically, lets say that the impedance of the right channel of your headphones is 33 ohms, whereas the left is just 32 ohms. If you use a 75 ohm impedance adapter, the values now become 108 and 107 respectively. So while the difference in impedance still remains 1 ohm, the percentage difference between them is now less. That means that the volume imbalance between the two becomes less as well. This is something I have been doing with lower impedance headphones for a long time, aside from soldering resistors to (on a side side, like adding 1 ohm to the left driver) my own personal pairs. The reason that it is 75 ohms, is that was the only compatible cable/adapter I could find for you guys other than just making it myself. 75 ohm adapters are used to convert the Etymotic ER-4P IEMs to having about the same (3 ohms more actually) the resistance of the ER-4S, so that's why it's already so readily available.
 
Yes, I actually do (courtesy of THX). Though they are pretty mixed in with other measurements from other headphones, and keep in mind that the room was not perfectly quiet. The earpads that I used for the measurement were the Dekoni protein leather memory foam earpads.
 
Here's a picture of the frequency response of the modded HP150 (bass ports open) both raw and compensated (for human hearing), and with and without impedance adapters respectively. (Blue: +impedance, raw; Purple: +impedance, compensated; Red: no impedance, raw; Brown: no impedance, compensated):

Here's the same test showing the results of their THD (luckily they measured that too, I didn't think I had them):

Here's another graph showing the raw (compensated will generally have little less mids and much less treble) frequency response curve of the modded (blue) and unmodded (purple, but there is a second purple unfortunately) HP150:

Here's the same test showing the THD (the purple one with the higher distortion is the unmodded HP150, the other one is one of my other custom headphones):

 
 

  Just to clarify - there have been no major changes to the mod?

That is correct.
 
Best Regards,
Lyova Margaryan of Tru-Fi Speakers

 

[DecentLevi]

Hello folks, just to clear things up - I was under the impression that the large internal ring of butyl on the HP-150 mod was new, hence why I said the newest revision is different. What we had actually determined in the end, was that for some strange reason the butyl ring does not gel with the Hp-100 mod, only the 150; and mysteriously the same mod sounded markedly better on the HP-150 than HP-100, although the only difference between the two is the shape and material of the earcups. I have an inkling that just maybe Lyova's newly modded HP-150 I tested may have newer / better drivers than the HP-100 because the difference seemed more than just a difference earcups.
 
One thing that's new however, is the optional addition of a 75-ohm resistor that you can add to the cable, for moderately improved refinement of the bass / dynamics. These can be ordered directly, and I would recommend getting two, to see if you prefer the sound of them single or double stacked:
 
https://www.amazon.com/dp/B00A2QJL0C
http://www.ebay.com/itm/272165203681

 

[norepeat]

Hi Lyova,
 
For the 1st graph, it looks like there is no change to frequency response with 75Ohms adapter.  Is the volume carefully matched between measurement?  It seems lines are on top of each other.
 
Colors are hard to see but from what I can guess, it looks like a good improvement with mod and 75 Ohms adapter seems to improve THD in mid and low frequency.
 
Best Regards,

 

[Packdemon]

  Hi Lyova,
 
For the 1st graph, it looks like there is no change to frequency response with 75Ohms adapter.  Is the volume carefully matched between measurement?  It seems lines are on top of each other.
 
Colors are hard to see but from what I can guess, it looks like a good improvement with mod and 75 Ohms adapter seems to improve THD in mid and low frequency.
 
Best Regards,

Hello norepeat,
 
I forgot to mention, I believe I was using 3 or 4 (75 ohm) adapters all at once so that way I could get a night and day difference. Yes, from what I observed, the software was increasing the voltage supplied until it reached a certain loudness. With the adapters it was running at 4 V, while without it it was running at just 800 mV.
 
It was rather unfortunate that the graphs turned out that way, but I am glad that you were still able to read it.
 
Best Regards,
Lyova Margaryan of Tru-Fi Speakers

 

[DecentLevi]

Lyova, I saw some earpads on Massdrop that look almost the same as my favorites from the Tru-Fi mod. Do you know anything about those?

 

[DecentLevi]

Confirming these are the same ones that have been the best on the HP 100/150 mods, and they're much cheaper than the original, check it:
https://www.massdrop.com/buy/19011
choose the DT770 premium memory foam option (leather, not velour)
 

 

[Packdemon]

DecentLevi

Those are the same ones I used to mod your headphones (DT770 w/ memory foam), but it doesn't seem like Massdrop has the image for it. It actually looks like this:


Best Regards,
Lyova Margaryan of Tru-Fi Speakers

 

[anticute]

  Confirming these are the same ones that have been the best on the HP 100/150 mods, and they're much cheaper than the original, check it:
https://www.massdrop.com/buy/19011
choose the DT770 premium memory foam option (leather, not velour)
 

$21.50 shipping to Europe. Was someone drunk and made a decimal error? Or maybe @WillBright would like to explain exactly what's included in that shipping cost? Someone's coming by with them to your house to put them on your headphones too?

 

[DecentLevi]

Well in that case I'd recommend just getting the earpads along with a modded headphone order. Or you can contact Lyova and just maybe he would ship you one at a lower cost if he has an extra

 

[anticute]

  Well in that case I'd recommend just getting the earpads along with a modded headphone order. Or you can contact Lyova and just maybe he would ship you one at a lower cost if he has an extra

I already bought the kit, so I'm set for the mod. I'll pay for decent earpads, but I'm not paying that kind of shipping for a pair of earpads. What's the shipping cost to the US?