Holographic sound ?

[ashok]

Sometimes the sound produced by equipment , either electronic or acoustic , is supposed to produce 'holographic' sound.

Does this hold for all recordings or recordings that have 'holographic sounding content ' ? Which recordings have such content ?

I've noticed that my planar dipole has a different image compared to my boxed speakers . I attribute this to the very complex reflected sounds that come from the speakers with both front and out of phase rear radiation. It sounds attractive at times but certainly is an artifact of the speakers and not something 'in' the recording.

Would like to know others opinions on this .
Cheers.

[sam9]

If you want to know more about how dipoles work tale a look at linkwitzlab.com. One could charaterise dipoles asless complex in many respects rather more complex due to the "orthagonal null field". That a fancy name for a simple notion

[ashok]

Hi Sam,
Would you really think that dipoles have a less complex signal ?

We would now be dealing with additional reflected sounds caused by the rear radiation as well as the reflections from the signals from the front. This is in addition to the direct frontal sound. Without any reflective surface near the speaker , the radiation will be much simpler as you have indicated.
Rooms have a large number of reflective surfaces and often they are not simple in form. The multiple reflected signals should be quite complex. Differing delays too.

Not all that is covered in the well visited Linkwitz site. It's a great web site !
Cheers.

[rdf]

Dipoles trade the strong side reflections of typical forward-firing speakers in typical domestic environments for stronger, but more delayed rear reflections typically with less high frequency energy. Again, depends on the installation and speakers but I don't consider superiority of one over the other is clear cut.
BTW, for holographic sound try movies.

[ashok]

"...............but I don't consider superiority of one over the other is clear cut....."

I think I agree with that . Every installation is unique in itself .

"....for holographic sound try movies......"

Sure. They sound great .
However I was refering to regular stereo recordings.

By the way in my listenig room there is a very long large window on one side wall and the wall on the other side is about 25 feet away .

[OzMikeH]

Using the same recording if several people hear the same effect on different systems you have a clear example of Holographic sound.

I would define Holographic sound as sound sources appearing to come from somewhere other than along a line between your speakers. (I'm disregarding the false head type recordings here)

One example I heard was from Us and them, symphonic pink floyd, the track: comfortably numb.
I was at a friend's house, he has a high quality pair of single driver fullrange speakers. AER Mk1. I think the single driver bit might be important.

I played my MP3 player through them, a 128 kilobit file so we're talking a very poor quality signal source.

The horn section of the orchestra is very clearly behind and slightly above the speakers about 3/4 of the way across. But ONLY when sitting in the Sweet spot.

I don't hear this effect with headphones from the MP3 player or from the original CD. Only with speakers.

How the sound appears away from the imaginary line? I have no idea. It was interesting that the effect was still there when the music has been compressed with MP3, that might provide some clues.

[sandyK]

There are countless recordings that give the illusion of a 3D soundstage. Unfortunately the majority of stereo amplifiers are lucky to give a soundstage that even extends past the width
of the speakers. Very few amplifiers are even able to give the illusion of sound behind the line of the speakers, or much in front of the speakers. There are numerous test discs that give a spoken narrative describing what you should be hearing from the various musical examples included. A good headfphone amplifier with quality headphones, is also capable of a 3D soundstage, however the front and rear depth obtained can never be as good as with speakers. The "Papa Doo Run Run" version of the hits of the Beachboys, is just one example of what can be achieved.Nimbus "Ambisonics" recordings are other examples. Unfortunately, most popular music is churned out using "panned mono" techniques, which results in the sound being spread in a straight line between the speakers. BTW, even "Beyonce-Naughty Girl" has an excellent 3D soundstage, as do some of the "making of" DVDs sometimes included with deluxe CD releases. e.g. Norah Jones-Not Too late" Deluxe version.

SandyK

[ashok]

This is great. Now we are getting a list of possible albums to use for checking out 'holographic' sound. Or should I be saying 3D sound ?
Thanks for the replies. Hope there will be more suggestions eventually.

In my case my dipole planar speakers give a far better 3D image than boxed speakers. But then that might just be a poor boxed speaker .

[I_Forgot]

Originally posted by sandyK
There are countless recordings that give the illusion of a 3D soundstage. Unfortunately the majority of stereo amplifiers are lucky to give a soundstage that even extends past the width
of the speakers. Very few amplifiers are even able to give the illusion of sound behind the line of the speakers, or much in front of the speakers.
SandyK

You are mistaken. The amplifier is not the problem. Speaker placement and room acoustics are the problem. You must place the speakers to eliminate early reflections. In some rooms this is nearly impossible without acoustic treatment.

Amplifier performance is all pretty much the same, maybe with minor differences. Speakers and the room they are in are ALL different and require some effort to find optimal placement.

All the money in the world thrown at amps and cables won't add up to the effect of moving your speakers about 6".

I_F

[el`Ol]

I find the most obvious difference between dipoles an boxes can be heard with recordings done with omnidirectional microphones (rare). With boxes I find these recordings are superior than those done with cardioid microphones. With dipole speakers I find them too diffuse.