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post #106 of 395

Holophonics seems to be a brand of a system to create binaural recordings.

post #107 of 395
Holophonics is a trade name for a specific binaural recording process by Zuccarelli (http://www.acousticintegrity.com/acousticintegrity/Holophonics.html) that includes certain features that the company feels are significant refinements to the basic binaural process. I heard a demo quite some years ago. The realism of sounds to the side, above and behind was impressive, but the forward image was much more vague, which is not atypical of most binaural systems. They did the haircut demo, and one particularly starling one was having a piece of newspaper thrown over your head. I don't recall any music demos. The recording hardware was never shown, but it was rumored that the guys from Zuccarelli carried it around in cases chained to their wrists. Probably rumor, but amusing.

There are samples on their web site.
post #108 of 395
Holophonics is a trade name for a specific binaural recording process by Zuccarelli (http://www.acousticintegrity.com/acousticintegrity/Holophonics.html) that includes certain features that the company feels are significant refinements to the basic binaural process. I heard a demo quite some years ago. The realism of sounds to the side, above and behind was impressive, but the forward image was much more vague, which is not atypical of most binaural systems. They did the haircut demo, and one particularly starling one was having a piece of newspaper thrown over your head. I don't recall any music demos. The recording hardware was never shown, but it was rumored that the guys from Zuccarelli carried it around in cases chained to their wrists. Probably rumor, but amusing.

There are samples on their web site.
post #109 of 395
Quote:
Originally Posted by jaddie View Post

Holophonics is a trade name for a specific binaural recording process by Zuccarelli (http://www.acousticintegrity.com/acousticintegrity/Holophonics.html) that includes certain features that the company feels are significant refinements to the basic binaural process. I heard a demo quite some years ago. The realism of sounds to the side, above and behind was impressive, but the forward image was much more vague, which is not atypical of most binaural systems. They did the haircut demo, and one particularly starling one was having a piece of newspaper thrown over your head. I don't recall any music demos. The recording hardware was never shown, but it was rumored that the guys from Zuccarelli carried it around in cases chained to their wrists. Probably rumor, but amusing.

There are samples on their web site.

How come it's not used in mainstream recordings? Imagine hearing a Mahler symphony from the perspective of a conductor. Mouthwatering prospect....

post #110 of 395
Quote:
Originally Posted by uchihaitachi View Post

How come it's not used in mainstream recordings? Imagine hearing a Mahler symphony from the perspective of a conductor. Mouthwatering prospect....
One reason not unique to Holophonics, but common to all binaural methods is the recordings sound poorly on conventional speaker, which may still be in the majority over headphones, though I have no stats. As to Holophonics not being more used than other binaural systems, it may be several reasons. The proprietary nature of the system, and possible licensing issues being just a few.
post #111 of 395

Profit incentive wise it makes no sense that recordings are not made in binaural forms more widely. Earphone or headphone users will be all over it!

post #112 of 395
Quote:
Originally Posted by uchihaitachi View Post

Profit incentive wise it makes no sense that recordings are not made in binaural forms more widely. Earphone or headphone users will be all over it!

It's a question of maintaining a "double inventory" of a single release, one for normal stereo, one for binaural.  This has been done several times, but it's sort of a mess because consumers in general don't know the difference.  And, stereo is more or less compatible to both markets, whereas binaural isn't.  They are partially dissimilar production paths, requiring separate masters and mastering chains, not that that is a huge expense, but it may not be viewed as necessary. 

 

I guess we have the opportunity to be vocal and express our desire for "headphone-only" releases to record companies.  Not sure how well received that would be, as labels that are forward-thinking (read:not mainstream) are already dealing with double, triple and quadruple inventory with CD, compressed, high bit rate, and vinyl releases.  The problem is, those could all share most of the production path, but binaural wouldn't.  

 

Somebody start a petition web page, we can all "sign" it.  

 

To be honest, I have purchase a couple of binaural releases of recordings I also have in conventional stereo.  The binaural versions haven't been compelling, even on headphones.  

 

Sort of a parallel test case is that of multi-channel music.  There is a huge installed base of 5.1+ channel systems now capable of multi-channel music playback, yet that version still is in the vast minority, seems to be confined to small releases, or re-mixes of vintage recordings.  You mustn't miss the 5.1 version of Dark Side of the Moon, for example.  Yet fresh new material is almost non-existent.  This, in the face of the fact that adding more channels is something anyone can hear, where upping the bit rate is mostly a psychological influence not clearly audible. 

 

If anyone want's to play with binarual recording, you can do it yourself pretty easily. There's even a thread about building your own binaural mics here: http://www.head-fi.org/t/232621/diy-binaural-mics

 

Good binaural mics in your own ears produce recordings that are pretty darn good when played with good supra-aural headphones back to your own ears.

post #113 of 395

What causes hiss in IEMs? Does impedance mismatch have anything to do with it?

post #114 of 395

Electronics produces noise. IEMs are usually very sensitive so they potentially convert this noise into a high enough SPL to be audible.

post #115 of 395

I heard about a rule of thumb between source and output impedance thant the source should be an eight of the output impedance.

 

But in the forums I read that big source impedance say 75 ohms with a 30 ohm earphone can 'improve the sound' and this guy posted a graph where the frequency bandwidth in fact increased and there was less treble roll off. What should I believe?

post #116 of 395

A very simple view at this is to look at the impedance curve of the headphone. The higher the amp's output impedance the more the headphones' frequency response will change according to its impedance curve.

 

As an example, take a headphone that has a completely flat frequency response. Impedance shows a peak at 100 Hz. High output impedance will cause a peak in the FR at 100 Hz.

Similarly, rising impedance towards upper treble will cause a treble "boost" with high output impedance.

post #117 of 395

BUt can a bandwidth really increase?

post #118 of 395

Sure, if the roll-off isn't abrupt but smooth then a smooth boost can increase the bandwidth (specified as X to Y Hz +/- Z dB). Of course there are limits to this. On the low end for example you need seal to contain the pressure and if there is no seal you have to boost a lot to get a little more lows. The result is just a disproportional increase in distortion. Similarly, if the driver "cannot" produce treble above frequency Y then boosting there won't help much.

 

I've seen some IEMs where a high output impedance causes some equalization that counteracts the deficiencies in the frequency response when measured from a low output impedance source. With most other headphones I'd say that high Z out makes them sound worse. And there's always the option to use a proper EQ to shape the sound to your liking. wink.gif


Edited by xnor - 4/16/13 at 6:46am
post #119 of 395

But in short, anything that you can do to changes in frequency response of earphones or headphones that occur due to high impedance sources relative to the earphone/headphone impedance can be done by EQing. Is this correct?

post #120 of 395

Using the impedance curve and output impedance is a pretty poor way to equalize since all you can somewhat control is the output impedance (usually just increase it by adding resistors). For some special cases this might work but even with a basic graphic EQ (fixed bands) you can do a lot more.

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