The Headcase Stax thread

[wink]

[HeadphoneAddict]

...I may get a set since I'm eternally curious about this stuff...the Leica system just killed any curiosity [in my friend] to try anything different. I do wonder why this hasn't happened to me yet with not one headphone ever coming close to besting my old SR-007 over the last 10 years.

You answered it yourself - eternal curiosity.

[Tachikoma]

Spritzer, how would you rate that transformer box with Lundahls that you recently sold here? Was it a decent option for driving O2s?

[wink]

Is that the one for sale over at H-F?

[Tachikoma]

Yeah, was for sale anyway.

[spritzer]

I made two of these boxes on the behest of Victor, one for him and one for me to try out ultra high end transformer solutions. Both look identical except one uses small stuck on feet and the other the rubber cones from Justin. Both used Lundahl LL1627 transformers which were a good choice in some ways but not in others. Too many windings and all the issues one has with that but the only real improvement over these would be a McIntosh style bifilar wound transformer. Sound wise these are the best transformers I've ever heard and shockingly transparent but not perfect. Transformers really aren't my thing and this project was to settle that once and for all. Same reason I'll take an SS amp over badly made tubes...

[wink]

http://www.pawel-acoustics.ch/pdf/hp-1_german.pdf

Anyone know about this?

[johnwmclean]

^ translation

The Headphone Processor by Pawel Acoustics is designed for use with high-quality high-end headphones designed. The electronic amplifier circuits are extremely wide bandwidth with low distortion and exceptionally designed, neutral sound. The selection and tuning of the sound components was carried out with love and devotion to music. For the following headphone models currently matched HP-1 devices are available: AKG K1000 Sennheiser HD800 (in preparation) STAX SR-202 / SR 303 / SR-404 / SR 007 and SR-4070 The Headphone Processor is simply looped into the signal path from the headphone amplifier. The function switch on the HP-1 allows the choice between the diffuse-field equalization, a neutral position and the bypass Binaural - mode. A function-level monitoring and display signals the operation and displays the correct modulation. The adaptation to different high signal levels is possible by means of 2-stage switch HI-LO on the back of the processor. The diffuse-field equalization leads to a fundamental improvement in sound. Their use is mainly a reproduction of dummy head stereophonic. The Binaural - mode, the diffuse field equalization expanded with the binaural transfer function. (Binaural head-related transfer function = both ears, with a natural listening experience both ears at the same time) The result is comparable with the usual loudspeaker reproduction. Also for the discerning ears in this setting should establish a permanent setting. When listening through headphones, creates the so-called in-head localization. Here we see the HP-1 binaural mode, the key improvements: The music playback through headphones is shifting from the back of the head forward and the proportions of the various noise sources appear in the right perspective. In particular, the realistic representation of space and convinces former figure distortions are a thing of the past.

[Clarkmc2]

If this will get the people at Head-Fi to shut up about the Smyth Realiser, I'm all for it. Personally, the normal presentation of headphones only bothers me when a lead instrument is on only one channel. If you don't think about soundstage, your brain fills in the gaps anyway.

All that said, would I like one of these? Hell yes, if I could afford it. The Smyth, never. If I want the exact presentation of my speakers, I'll listen to them. I LIKE the way my Stax OIIs sound.

Edited May 4, 2012 by Clarkmc2

[wink]

Yay... Good point.

[n3rdling]

What if you want the presentation of other speakers as well?

[TruBrew]

If this will get the people at Head-Fi to shut up about the Smyth Realiser, I'm all for it. Personally, the normal presentation of headphones only bothers me when a lead instrument is on only one channel. If you don't think about soundstage, your brain fills in the gaps anyway.

All that said, would I like one of these? Hell yes, if I could afford it. The Smyth, never. If I want the exact presentation of my speakers, I'll listen to them. I LIKE the way my Stax OIIs sound.

I am going to have to disagree with you a bit. This would in no way replace the Realiser. My assumption is that this device intends to give your headphones Sigma like presentation. That would be very cool, but is no like the Realiser. As you could guess I do own one. I use it 99% of the time for movies and TV. It does a fantastic job of recreating surround sound. Sure it works for stereo too, but like you I also like the sound of my Omega2. If I use the Realiser, I lose that. This device would be cool because it should retain the headphones natural sound signature. I wouldn't buy one. Sure I would like to try it out, but it's use is too limiting.

I am not an expert on audio, so I apologize if any of the information I provided is incorrect. As for your statement about the Realiser and HF, sillysally imidiatly come to mind. I would block him, but then I would miss all of the crazy that comes from his mouth.

Edited May 4, 2012 by TruBrew

[wink]

sillysally can be a trip at times.

[arnaud]

If this will get the people at Head-Fi to shut up about the Smyth Realiser, I'm all for it. Personally, the normal presentation of headphones only bothers me when a lead instrument is on only one channel. If you don't think about soundstage, your brain fills in the gaps anyway.

All that said, would I like one of these? Hell yes, if I could afford it. The Smyth, never. If I want the exact presentation of my speakers, I'll listen to them. I LIKE the way my Stax OIIs sound.

You're missing the point about the realiser. I agree that adding a speaker coloration to your headphone isn't a fantastic idea to start with (and I would have allowed to simply try to obtain actual HRTFs rather than raw data lumping the whole reproduction chain). However, acquiring personalized binaural response goes a long way toward making the out of head experience all the more believable. As long as you're calibrating it with a well setup system (both room treatment and speaker performance), it is a reasonable compromise toward getting binaural experience with all your stereo recordings using headphones.

The swiss product mentioned here appears to be a more traditional active crossfeed filter, albeit based on an actual dummy head HRTF + headphone specific compensation for the same head. Ignoring the fact you don't listen like the dummy head (still better than nothing for those recordings that have really unnatural L/R separation), another major challenge is to approximate such measured HRTF with an analog filter (there's a reason why people use DSPs for this and simply use measured data / convolve in real time).

[wink]

The person who buys these phones will be in for a surprise when they try them on their normal bias socket.

http://www.ebay.com.au/itm/STAX-SR-007-OMEGA2-HEADPHONE-SET-/200751032787?pt=UK_AudioVisualElectronics_HomeAudioHiFi_Headphones&hash=item2ebdb1a9d3

[spritzer]

Going on what few internal pics of the Pawel stuff there are it does look like a clone of the Stax circuit adjusted for the newer sets. They also had some amps but who knows what's inside...

[complin]

I am going to have to disagree with you a bit. This would in no way replace the Realiser. ................................ Sure it works for stereo too, but like you I also like the sound of my Omega2. If I use the Realiser, I lose that. This device would be cool because it should retain the headphones natural sound signature. I wouldn't buy one. Sure I would like to try it out, but it's use is too limiting.

Not quite clear what you are saying how the realiser impacts on the sound? I thought they were designed to use with the Stax 202's? So how do they impact the Omega 2?

They are supposed to simulate the sound of your speakers in your specific room setup so thats bound to impact on both presentation and frequency response. They also come with a ready saved simulation which is probably somewhat different. Never heard the realiser but intrigued how it differs from crossfeed. Any comments from realiser owners appreciated

[arnaud]

Never heard the realiser but intrigued how it differs from crossfeed. Any comments from realiser owners appreciated

I will let the owners add to this, but the answer to your question is pretty straightforward:

- A crossfeed is typically just that: bleeding some of the left channel into the right ear and vice-versa to simulate how each speaker is heard by both ears vs. your headphone experience. You can go to some more complexity by including some delay line (to simulate inter-aural delay for a specific speaker heading) as well as some frequency alteration (to account for the shadowing effect of sound diffracting around the head). But essentially, any implementation using analog active filters is a crude approximation of the real mechanism, not-withstanding the fact that the peculiar geometry of everyone's head and ear (outer & inner) makes it difficult to come up with the right equalization for all.

- The realiser will simply record your head-specific relationship between a given loudspeaker heading (say +/-30 degrees in front of you for a stereo setup) and both left / right ears response at the entrance at the ear canal. It is simply recording that "Head Related Transfer Function" by feeding some kind of white noise or sine sweep and recording the response. You end up with an impulse response that will later on be convolved with the music in real time to convert the speakers L/R signal into a "binaural" signal that corresponds to you hearing it for the given loudspeakers position.

- You might recall that when playing this "binaural" signal back, you're using headphones, hence the sound is sort of being filtered twice by your outer ear shape. So, you typically need to filter out that effect and equalize out the response of a specific headphone to the exact same microphones position at the entrance of the ear canal. This pawel product discussed above is doing it for some stax headphones and it's using binaural recordings from a dummy head which is supposed to mimic how the average person hears (the issue is with the deviation across the population not the average though...).

- Another specific of the realizer is that it's geared toward multi-channel music and movie mixing engineers so, actually, it's not quite recording HRTFs (which are characterizing how a given head hears independently of the loudspeaker characteristics, amps, rooms, microphones) but lumping the dynamics of everything in the chain: e.g. realiser D/A > preamp > amp > loudspeaker > room > your head > microphones > realiser A/D. This is the reason why they refer to PRIR (Personalize Room Impulse Response) rather than HRTFs.

By now, you might be just going tldr but I'll have tried as best as I could...

Edited May 5, 2012 by arnaud

[Beefy]

- A crossfeed is typically just that: bleeding some of the left channel into the right ear and vice-versa to simulate how each speaker is heard by both ears vs. your headphone experience.

Can we just build an amp with bad stereo crosstalk numbers and pretend it is crossfeed?

[arnaud]

Can we just build an amp with bad stereo crosstalk numbers and pretend it is crossfeed?

Yeah, it quickly gets silly when you think about all the hard work to eliminate cross-talk in the amp ^ ^

[Clarkmc2]

My old Marantz gear had a stereo/mono control for headphones. Mono would cut the separation to 10dB. It wasn't adjustable but it dealt with those bad old 100% separation mixes OK.

[spritzer]

Can we just build an amp with bad stereo crosstalk numbers and pretend it is crossfeed?

I have an even better way, just swap one phase from left to right at the Stax plug. Instant crossfeed!!!

[johnwmclean]

Speaking of crossfeed a dabble with TB isone is well worth it, especially considering it’s free 15 day trial period.

All of my classical and well recorded acoustic music has benefited greatly.

I’ve not gone nuts with the settings, I just use the default and adjust the speakers distance for 2 metres and left it.

It’s one the best upgrades I’ve experienced with headphones.

[Clarkmc2]

What if you want the presentation of other speakers as well?

I haven't heard any that I like better than what I have already.

[arnaud]

Speaking of crossfeed a dabble with TB isone is well worth it, especially considering it’s free 15 day trial period.

All of my classical and well recorded acoustic music has benefited greatly.

I’ve not gone nuts with the settings, I just use the default and adjust the speakers distance for 2 metres and left it.

It’s one the best upgrades I’ve experienced with headphones.

Thanks for this, I want to try it. Haven't found a way yet to integrate (the vst filters) with iTunes or another free player for OS X, any idea?