[Stevemitchell]

Over the years, I've heard erudite and passionate descriptions of "imaging" on this forum as attributed to speakers, headphones, and earbuds.

Imaging......

Imaging?

Just what the hell is "imaging" anyway?  As compared to what?

As an Audio Engineer I've been working with recording (in this case - Orchestra) music for years.

When I go see the DSO or the Fort Worth Symphony in concert, I always hear everything that is "right" with the world - 23% direct, 67% reflected sound, or thereabouts .

For years, I've tried to "link" what I hear in the Myerson, or Bass Hall to the recordings that I produce.  I'm not always successful.

As to why - let's go way back to my "Genisis" in starting with audio.

As with most kids in the 60's and 70's, my exposure to recorded orchestral music was mostly (regardless of recording label) recordings of multi-channel MONO spread across what we've now come to know as the "Stereo Field" - that aural phenomenon playing to our ears, posing as a multitude of sounds, starting from left-to-right, to simulate what we'd hear in a concert hall of sorts.  

Not always aurally accurate, but dang it sure did sound purty.

I used the term "multi-channel mono" above - All that means is that some well-educated recording engineer, using 32 or so Telefunken-Neumann microphones, captured every detail of a performance available, and ground those sounds into the vinyl record that I purchased at the local record store in Tulsa as a youth.  The engineer dutifully used his best experience to "pan left to right" the sounds of all these microphones to their appropriate place in the sacrosanct "left-to-right" sound field.

What we as consumers had at this point was the basic 2-channel stereo mix, interspersed with multi-tudenous channels of instrument-solo highlights spread throughout from left to right.

However listening with headphones as I was very early into my music hobby, I was always aware that the solo instruments I listened to had absolutely no "air" around then - the sound for them was DIRECT, with no ambience 'around' their sound whatsoever - those sounds that naturally started at the instrument "center" and decayed out, left and right to infinity.

As a kid who simply loved the music, I didn't really care or realize that what I was listening to was SOOO unlike real life.

Fast-forward 15 years.  

Now, post-education that included the study of acoustics and psycho-acoustics, sound propegation, and a recording engineering degree obtained in Dallas, I realized that what I heard on my beloved music recordings didn't nearly match what I was hearing later on in life - that is many, many attendances to symphony concerts as described above.

I realized that I now truly knew what was meant when someone described "imaging" - how well the sound of the recording, as relayed by whatever sound device was transferring that sound to my ears -

Could I close my eyes and effectively visualize what I might see if the performance in my mind, based on sound queues from the strictly audio-based recording?

=============

I've read MANY reviews here on Head-Fi of hardware, reproducing recordings here in which writers describe in detail what their opinion of a sound-devices "imaging" capabilities are - but (as far as I can tell) without the knowledge of how the recording they're using in their review was actually recorded.

I don't want to disrespect or discredit ANYONE - I just want to know how evaluations on "imaging" are made in detail, and whether MY interpretation of what 'imaging' may be is accurate.

Thanks for reading,

Stevemitchell
 

 

[wuwhere]

The placement of the mikes is also important, sideways and front to back. When recording, if the signal strength of all those mikes are the same then mixed together in a recording, would a listener of the recording be able to distinguish the placement of the instruments without being present during the recording?

 

[shamu144]

Inherently, I would think that headphones have limitations and aren't really capable of providing a trully natural sound field without some crossfeed enhancer, or eventually with proper binaural recording techniques. I also would think that the recording techniques and mikes used will influence heavily the final results.
 
Stevemitchell, may I ask you which equalization method you believe as a profesional is more accurate at providing a credible imaging in headphones for a wide range of recordings: diffuse field equalization or free field equalization. I understand there is lot's of discussion around this question, and it is far from beeing all black or white.
 
Yet for me, proper imaging would appear to my ears as coherent sounds (respect the distances and perspective between instruments in all dimensions but especially width and depth), stable (not floating around but precisely located), in a sound field that would provide enough spatial cues to be able to simulate a credible musical event with respect to the original recording location (a concert hall should offer a very different sound field from a studio).

 

[skipgap]

  Being able to perceive the 3rd dimension would be ideal. Like pinging in a concert hall. For it to be stable and focused, Hp's are probably limited but i can get a good an unbelievable experince from Koss ksc75's listening to Virtual Barber shop. Is there not the Chesky album from the spring for the headphone cult out there. That was supposedly the one where he got every pro he could think of to pull this off and it's supposed  a gift from these guys to a certain extent. Holophonic and Binaural are what I think you would look for. Isn't it all relative and best left up to the imagination though.

 

[edstrelow]

Quote:

Inherently, I would think that headphones have limitations and aren't really capable of providing a trully natural sound field without some crossfeed enhancer, or eventually with proper binaural recording techniques. I also would think that the recording techniques and mikes used will influence heavily the final results.
 
 

Binaural recording (i.e. recording with mcrophones in dummy heads, or even real heads) is the gold standard of "imaging" with headphones although still not perfect in producing a sense of sound being in front of one.  Of course it doesn't work with speakers.
 
As regards the initial question of what is imaging, it is simply localizing sound sources in space.  Generally we are good at left-right discrimination, and poor at up-down and  front back.  Localization results from the brain interpreting differences in signals at the two ears, principally amplitude and timing differences.  Since most recording techniques, except binaural, mess up time and phase differences such that they don't resemble what one would hear with ones own ear, in effect only amplitude differences are functionally important.  That's why there are volume sliders in a mixing consol.  .
 
A second issue however is probably best called "soundfield," which includes how wide the field appears to be.  For example if you blend left and right channels you can narrow the stereo image or eliminate it completely giving you a monaural signal.  However I think most of us are also think about how good the image sounds in regard to things like ambience and naturalness.  Bianural recordings solve the problem if all you want is playback through conventional headphones.  Otherwise there are many ways to get a good soundfield.  I have heard many good recordings such as Telarc using minimalist miking techniques (i.e. down to 2 mics) and others using arrays of mikes. It seems to be as much a matter of art as science and highly subjective.
 
 
Re:crossfeed.  This is really not the answer.  If you feel that images are too widely spaced then certainly blend the two channels.  I have personally never found this a problem and when I did have a blend control, I tried it a few times and then never used it again.
 
That beilef that somehow headphones suffer in imaging compared to speakers is  incorrect and I am always amazed to see this claim in a headphone site where I would think the members would have a better grasp of what headphones and speakers actually do.
 
Speakers in fact mess up stereo imaging because they take 2 signals, i.e. left and right channel,  and convert them into 4 signals in which for example the left channel goes to the left ear and now to the right ear with a small time delay - and similarly for the right ear.  Remember the ears only deal with 2 signals, so mixing in extra so-called "phantom" channels is a recipe for screwing up localization. I still have Polk's SDA speaker system which does  a cancellation of the phantom signals.  And guess what - imaging is improved radically.  Sound sources are almost tangible.  You can switch the cancellation in and out and the effect is very striking.   But all that Polk and its imitators are doing is making speakers sound like headphones getting back to 2 unadulterated signals.
 
The main advantage I see with speakers is that they get away from the in-the-head sound of headphones, because they are so far away from the head.  And you don't have to wear anything on your head.
 
 

 

[Stevemitchell]

Excellent post Ed.  I've been listening to Robert Woods-produced, Jack Renner-engineered recordings on Telarc since that first "Bass drum heard 'round the world" in 1978.  I have about 80 or so recordings from Telarc, and I always check out new ones.  However, since being sold to Concord Music, the recent recordings don't appeal to me much.
 
Jack pioneered the minimalist technique 40 years ago, L+R and a (little) Center, and taught all of his protégés in the technique as well.  I'll admit that the 'stereo-field' is too wide on those recordings too, but virtually all instruments have 'air' around them, except when they insist on mic'ing a soloist, mainly vocal or sometimes even harmonica.  However, big solo instruments like piano, or big sound like horn mostly never get their own mics. 
 
Great Discussion!!

 

[googleli]

As much as I like my SR009 and LCD3 and my custom IEMs,  I don't think there is any imaging to speak of in headphones and IEMs. One would probably need a Smyth Realizer to have proper imaging in headphones or IEMs.

 

[NamelessPFG]

My understanding of the matter is that while soundstage describes how separated sounds can seem (almost as if they were outside of the head in some cases), imaging describes how easily those sounds can be located-from which direction, and how far away.
 
As already mentioned, binaural is as good as it gets when it comes to headphone imaging. I found it so good that I stopped caring about surround speakers. However, I have found that while I can get a good sense of direction, I still don't have a very good sense of distance, meaning that it still doesn't really sound in front/behind/above/below/wherever of me more than a foot at most. Perhaps it's because most of the surround-to-binaural technologies found in external DSPs, sound cards, and so forth use generic HRTFs, and as you know, everyone has a unique HRTF, even if most of them fall within some sort of average.
 
However, I'm looking at imaging from a different perspective. Everyone else thinks of it in a music context. I'm thinking of it in a gaming context-a situational awareness and immersion advantage, if you will. Precise imaging is like having an aural wallhack. (Of course, there's that whole issue with game developers throwing out proper 3D sound fields in favor of 7.1 (2D, no height) at most and stereo (1D, left/right panning only) at worst thanks to the prevalence of software audio engines with no binaural options that downmix the sound before it even hits the sound device driver...)

 

[shamu144]

You very well might be right. Binaural is hardly a gold standard, because we need individual binaural recording matched to our very own HRTF to be fully effective. At least, these are the conclusions drawn from David Griesinger here.
 
I am afraid proper imaging with headphone is nothing but a compromise (and a very good one in some cases). 
 
Quote:

As already mentioned, binaural is as good as it gets when it comes to headphone imaging. I found it so good that I stopped caring about surround speakers. However, I have found that while I can get a good sense of direction, I still don't have a very good sense of distance, meaning that it still doesn't really sound in front/behind/above/below/wherever of me more than a foot at most. Perhaps it's because most of the surround-to-binaural technologies found in external DSPs, sound cards, and so forth use generic HRTFs, and as you know, everyone has a unique HRTF, even if most of them fall within some sort of average.

 

 

[Edoardo]

Quote:

I've read MANY reviews here on Head-Fi of hardware, reproducing recordings here in which writers describe in detail what their opinion of a sound-devices "imaging" capabilities are - but (as far as I can tell) without the knowledge of how the recording they're using in their review was actually recorded.
 
Thanks for reading,
 
Stevemitchell
 

great point here. thanks for the contribution
 

 

[skipgap]

Dolby Headphone Wrapper also
 

 

[skipgap]

Has anybody heard Silent Speakers II or Ascend Sierra-1 nrt's for imaging.