| 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 .
:D |
|
|
| I_Forgot |
| quote: | 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. |
|
|
| oshifis |
| The Pink Floyd 1977 album Animals is another good example. |
|
|
| sam9 |
Going back to dipoles, Linkwitz claims that the relative absence of side and vertical reflections excites fewer room nodes and reduces the contribution of "room effects" and the need for room treatments. The principle placement requirement is that they be at least 24 inches from the rear wall, although I've violated that slightly with out much consequence.
Regarding holography, I've used a Carver C-9 off and on for 20 years and dipoles (Magnepans, specifically) have been the easiest to set up for good results. Box enclosure seem to be more fussy about placement to get the C-9 effects to work. I'm only speculating that the same would be true with recordings of holographic content. |
|
|
| rdf |
| quote: | Originally posted by sam9
I'm only speculating that the same would be true with recordings of holographic content. |
That's why I recommend movies, anything five years and newer. To my ear it's very obvious the standard surround formats' (ex. Dolby) side and rear channels are encoded with a Head Related Transfer Function algorithm. All my DVD players fold the surround channels into the fronts on 2 channel playback. A decent single pair of speakers carefully placed to avoid strong first reflections in my experience will allow the ear to catch and decode much of that HRTF information and recreate a good portion of the surround experience. Phantom sources appear above, well forward and outside the speaker boudaries and in some rare cases even behind the listener. A completely artificial effect of course but without those extra speakers also quite fragile. Once successfully set up that care in placement also pays dividends on minimally mic'd recordings and more recent pop stuff also using HRTF effect such as Beck's 'Guerlito' and the Flaming Lips releases. As 'holographic' an expereince as I've heard over two speakers. |
|
|
| tubewade |
Agreed that it is all about whether it is on the original recording or not and then about how the speakers interact with the room. Most of the spatial cues that result in this kind of imaging were lost in the 'mixing' of the original recording. The best sounding ones are those made with only two microphones, a left and a right. I've demonstrated this to myself many times by making recordings with only two omni mics.
My experience with dipoles, primarily electrostats, is their imaging is outstanding when set up correctly. Boxed monopole speakers can also image pretty well, though, if done correctly.
The only way I see that amplifiers could destroy a good stereo image is if the left and right channels did not have the same phase response somehow. |
|
|
| sandyK |
I_ forgot
Several of us have been able to achieve what you are saying is impossible, using entirely different speakers, in entirely different rooms, using the same equipment. The rooms, must however, sound reasonable to start with. Are you suggesting that all the people who have put out various Test recordings, including Opus "Depth of Image" are all lying?
All amplifier performance is NOT all pretty much the same !
Perhaps you should try downloading the binaural recording recently posted in a link in "Everything Else", and see for yourself?
I hate MP3 as a format, but I did download the file, and I was able to hear what the person who recorded it claimed, even on the PC headphone amplifier. If you are then unable to hear a 3 dimensional soundstage, then you should reconsider your position that all amplifiers sound pretty much the same.?
SandyK |
|
|
| SY |
| Sandy, I don't think you got what I_F said- he did not claim that depth was impossible, he just said that it's a function of source material, speakers, and room, not amplification or cables. Within reason (e.g., excluding some horrible amp with bad distortion or 6dB of separation...), my experience is that he's right. My last set of dynamic speakers are being run on a very cheap B&K amp at a friend's house and he gets every bit of depth and soundstaging that I did using some pretty fine tube equipment. |
|
|
| I_Forgot |
| quote: | Originally posted by sandyK
I_ forgot
Several of us have been able to achieve what you are saying is impossible, using entirely different speakers, in entirely different rooms, using the same equipment. The rooms, must however, sound reasonable to start with. Are you suggesting that all the people who have put out various Test recordings, including Opus "Depth of Image" are all lying? |
Different speakers in different rooms is fine. My point is that the amp makes almost no difference in regard to "image", except the financial image of the owner. You can achieve excellent performance with many speakers in different rooms but only if you pay careful attention to the position of the speakers and listener and use reasonable acoustic treatment of the room.
It would not be the first time in the history of audio that someone lied to sell a product...
| quote: | Originally posted by sandyK
All amplifier performance is NOT all pretty much the same !
Perhaps you should try downloading the binaural recording recently posted in a link in "Everything Else", and see for yourself?
I hate MP3 as a format, but I did download the file, and I was able to hear what the person who recorded it claimed, even on the PC headphone amplifier. If you are then unable to hear a 3 dimensional soundstage, then you should reconsider your position that all amplifiers sound pretty much the same.?
SandyK |
I have made my own binaural recordings and have a thorough understanding of the process and a lot of experience with the resulting recordings. It doesn't take much of an amp to reproduce their realistic soundfield through headphones. If you have an amp that doesn't do it, your amp is broken. You even discovered that a PC headphone amp works. With all the noise and garbage floating around in a PC that would presumably interfere with the realism of the recording why do you continue to think that something special is required? I stand by my contention that properly functioning amps sound pretty much the same. How could it be otherwise?
The soundfield is a function of the frequency response and the phase response of the system. Amps do not shift phase by much over the audible frequency range and they all have pretty much flat response over that range. As long as the headphones behave normally (any marginally decent headphone will do), you will experience the soundfield that was recorded.
I_F |
|
|
| sandyK |
Sy and I_Forgot
It would appaear that, on the surface at least, that neither of you have had the opportunity to audition many pieces of high end audio equipment at HI-FI shows ,or the showrooms of better specialist HI-FI dealers. I will admit , however, that even premium products like some of the Krell Amplifiers sometimes have a very poor soundstage.There have been many other posts on this subject elsewhere. The AKSA series of amplifiers by Hugh Dean,for example, have achieved almost cult status in DiyAudio Forum because they do have a much better than normal 3D soundstage.
There are very many forum members who would disagree with you on this subject This includes some highly respected designers. Just because many amplifiers based solely on the
writings of Douglas Self (without modifications) are described with regular monotony, as "Blameless and Sterile" , does not mean that all amplifiers sound like this. As for the majority of valve amplifiers , they are not wideband enough to retain the higher order harmonics that helps create a good soundstage. Most valve amplifiers also do not like it when many things are happening at once. They may however sound quite good on less demanding material, even DTV audio. I will not go into the reasons for this,as they have been explained many times elswhere. I would expect that DiyAudio Moderators,in general would have quite a good grasp of the subject.
Do you have a "Moderators Only" discussion group ? If so, perhaps you couild see what other moderators think about Soundstage requirements etc.
SandyK |
|
|
| OzMikeH |
We all agree the information (whatever that is) must be in the recording. I suggest we exclude binaural recordings because that has been discussed elsewhere many times.
Most of us agree that early reflections must be eliminated. Either by highly directional speakers or by room treatments. Apparently planars and dipoles are good, presumably from the null zone of front and rear waves overlapping. Horns are also good, presumably from their directionality. The early reflection argument carries some weight. Higher frequencies are particularly important.
Whatever MP3 does to destroy other detail in the music does not affect the effect (much).
My thoughts on amplifiers:
There are some amplifiers out there with massive distortion figures which still sound "nice". No amplifier can stop early reflections.
it is clear than MP3 doesn't kill it so any moderately competent amplifier should work.
I must say I've only auditioned one tube amp, a modular amp built by a particularly bright and experienced electronic technician. It is a single ended tube amp with output transformer, feedback pickup was about 40% of the secondary. I listened as a triode amp, a pentode amp and with varying levels of negative feedback in both modes. I think my hearing might be reasonable, I could pick the negative feedback setting to within 2dB. Pentode sounded more accurate, triode was warmer and more mellow. No negative feedback was atrocious.
The horn section effect I described earlier was still there with the tube amp in-between and with the little headphone amp in my cheap, single AAA powered MP3 player connected directly to the speakers. The speakers were 103dB/W/m so were listenable with 150mW.
Imaging from amplifiers IMHO is rubbish, However: a muddy mellow tube amp may remove distracting high frequency detail and make the effect more obvious. The reality is the most experienced and knowledgeable reviewers of these high end amplifiers can no longer detect a third of their output. We have to remember they are only describing the bottom two thirds of what these amps are doing to the signal.
I suspect we'll have to agree to disagree about the amplifiers Sandyk, We can continue to constructively examine other aspects of the holographic effect.
Fidelity is not as important as I thought it would be. Something can sound pretty terrible and still image well.
Now to get back onto the meat of the topic.
There are two areas I think should be considered in detail:
The recording process, in particular Mic sensitivity pattern and room arrangement.
The acoustic aspects of the playback situation. Speaker radiation pattens, reflections in the room, speaker positioning, Is there an optimum angle from the listener to each speaker? Is this dependent of the recording?
If anyone notes the effect on a particular song please list what it is including the elapsed time of the track. If nothing else we can compile a list of interesting tracks to listen to this effect on.
Several people describing the same recording might discover some interesting differences. |
|
|
| sandyK |
OzMikeH
Here is a track for starters, that many people will have in their collection : Kim Carnes-Bette Davis Eyes.
SandyK |
|
|
| SY |
| quote: | | It would appaear that, on the surface at least, that neither of you have had the opportunity to audition many pieces of high end audio equipment at HI-FI shows ,or the showrooms of better specialist HI-FI dealers. |
You would be incorrect.
IME, those are pretty lousy places to do serious evaluation. Unfamiliar rooms, unfamiliar systems, poor setup (at shows, especially)... and, of course, lots of subtle and not-so-subtle coaching by people who have something to sell.
BTW, just to dispel an incorrect assumption, the moderators are not chosen because of their fabulous systems, their long experience in audio, nor engineering skills. Their opinions are worth no more or no less than any other member. |
|
|
| sandyK |
SY
My apologies.
I agree that many demonstrations at HI-FI shows were in small
rooms, and they were often poorly setup,and relied mainly on their glossy brochures. The better demonstrations "DownUnder" were usually in much bigger rooms with seating,but still not ideal.
My friends and myself, often have listening sessions in each other's homes, doing comparisons, especially after modifications.We also use a compilation CD,as well as other high quality material. We often had access to some high end equipment for comparison purposes, including an AU$6,000 Krell Preamplifier, and a Mararantz SA11 SACD player (AU$4,100 currently) .
I must admit that I did think that the moderators were usually chosen for their depth of experience in a particular area, so as to inject a degree of leadership into some discussions. This often does appear to be the case in many instances,but perhaps because they have been involved for some time ? |
|
|
| BWRX |
| quote: | Originally posted by tubewade
The only way I see that amplifiers could destroy a good stereo image is if the left and right channels did not have the same phase response somehow. |
Imaging can be affected by a gain mismatch between channels of an amp. This basically has the same effect as a balance control in that it can shift the image off center. You also have to take into account channel separation over the audible frequency range. A fully dual mono amp is as good as you can get in terms of channel separation. A fully dual mono signal chain before the amp would be nice too!
The main things we can experiment with to obtain good imaging are speaker placement, listening position, and room acoustics. Of course the quality of the recording is paramount, but rarely do we ever have control over that. |
|
|
| SY |
Sandy, OT stuff first: Moderators (all volunteer) will have basic competence in electronics, enough so to follow discussions, but are mainly there to keep things on track. They are chosen from active participants. Any post showing the cop icon is an official moderator message. Any post without it is just the moderator posting as an ordinary member (which we are, first and foremost).
On topic: I've managed over the past 40 years or so that I've been building hifi equipment to listen to some pretty exotic systems in private homes and in commercial settings, including the personal systems of some pretty well-known high end designers. What that has done, sadly, is to cause me to judge things on how they sound compared to live music, not what their reputation is, what they cost, what the back story is, or what the designer or builder thinks I should be hearing.
If you think that you can perceive differences in depth or dimensionality between different amplifiers (assuming basic competence in distortion, bandwidth, separation, and noise, and a level-matched comparison within the amps' power ratings), then set up a controlled test, show a significant result, and your paper in JAES will be one of the most-cited. And you'll be in line for the Randi Foundation's million dollar prize. Please send me 10% for making the suggestion.:D |
|
|
| BWRX |
| quote: | Originally posted by OzMikeH
Whatever MP3 does to destroy other detail in the music does not affect the effect (much). |
Compression should not affect imaging unless the compression involves merging the channel information. This is one reason to never encode/compress using a joint stereo option. It merges closely correlated stereo information into a mono signal in order to obtain a higher compression ratio. |
|
|
| sandyK |
BWRX
Maximum channel separation and balance. is far more important than it is usually given credit for. A good attenuator such as the DACT2 will give you this, as well as much higher bandwidth than any dual volume control.Mono construction can be very worthwhile, as can very low impedance supply for the front ends. I don't just mean the usual voltage regulators either.Lowest possible noise in all components is also necessary to extract the ambience information, which is often at a very low level.
DTV audio is particularly hard to extract a good soundstage from, as it starts out around -25dB maximum level. But it can be done,with due attention to the switchmode PSU bridge rectifiers etc. in the STB.There is no single "magic bullet". A good soundstage is the result of attention to detail in many areas. Yes, the speakers and room acoustics are very important too.
SandyK |
|
|
| OzMikeH |
I just searched "Ambisonics" in Amazon.com looking for the albums SandyK mentioned, I got many, many pages of books.
Then I Googled it. Still reading.. Very interesting.
I see what you mean, subtle faint little echoes in the recording add to the ambience. Don't forget to switch off the air conditioner too!
|
|
|
| sandyK |
OzMikeH
Yes, or the PC over the other side of the room. As you further improve bandwidth , and lower overall system S/N the effects are less fragile. Some other good recordings (among many) are :
Neil Diamond-Hot August Night. This is excellent,despite the age of the recording."Soolaimon" is an excellent example from this album. Papa Doo Run Run-California Project: most of the Telarc album, especially "I Get Around" and even more so, "Good Vibrations" This is how the Beach Boys should have sounded !
The bonus DVD from the deluxe version of the Norah Jones album
"Not Too Late" has excellent 48KHZ LPCM audio. You are even able to compare the Music Video with the original live performance, which BTW, is markedly better, particularly in dynamics Don Dorsey's "Ascent" in my friends , and my system fills the complete listening area with sound. (Telarc? )
The Telarc album "Beethoven or Bust" from Don Dorsey is also very dimensional ("Digital and other authentic period syntesizers")Track2 "Mixed Bagatelles" has a synthesized "Car Smash" right out of the blue, at the end. It is guaranteed to frighten the
SH-T out of you if you don't know it is coming!
These are just a few of numerous examples.
As I said previously, the quality of the amplification IS important .
My equipment is Class A solid state preamplifier ,and 15W/Ch
Class A Amplifier. It is fed via a highly modified Musical Fidelity
X-DAC V3, which resamples to 24 bits 192KHZ.
SandyK |
|
|
| I_Forgot |
| quote: | Originally posted by BWRX
Compression should not affect imaging unless the compression involves merging the channel information. This is one reason to never encode/compress using a joint stereo option. It merges closely correlated stereo information into a mono signal in order to obtain a higher compression ratio. |
Wrong! Joint stereo is a mid/side encoding that takes advantage of the common stuff contained in the two channels to enable BETTER quality for a given bit rate. Instead of encoding the two channels as two mono signals which have a lot of common info, the sum (L+R) and difference (L-R) are encoded. When you subtract the two channels you eliminate the common data, mainly in-phase low frequency stuff, thus reducing data required to represent the common stuff which is already encoded in the sum channel. The original channels are reconstructed by taking the sum and difference between the two signals (L+R and L-R). (L+R) + (L-R)= 2L and (L+R) - (L-R)= 2R. Playback recovers the both channels as they were before encoding (with compression artifacts, of course, if lossy compression is used).
You can read more about it here:
http://harmsy.freeuk.com/mostync/
Joint stereo is your friend.
I_F |
|
|
| zapnspark |
I'm staying out of this debate for the moment.
I would like to mention a new CD that might interest some of you.
The Zenph "re-recording" of Glenn Gould "playing" his 1955 recording of the Goldberg Variations.
If that doesn't make sense to you, see the following link:
http://zenph.com/sept25.html
This is a SACD disc. You can listen to it in stereo, surround and
binaural (tracks 33 - 64).
I think it is a fascinating technical accomplishment.
Gould without the humming, singing, tape hiss or the squeaky chair.
If you can't tolerate Glenn Gould (or Bach), then this will just be torture for you. |
|
|
| BWRX |
| quote: | Originally posted by I_Forgot
Wrong! Joint stereo is a mid/side encoding that takes advantage of the common stuff contained in the two channels to enable BETTER quality for a given bit rate. |
I_F, thank you for clearing that up! I was clearly misinformed and will now tell my source that he was misinformed as well :o |
|
|
| sam9 |
zapnspark,
Sounds like 21st century Vorsetzer. I'm a little dubious but maybe I'll check it out. I hope they chose to leave out the vocal obligato !!!! I alway found that annoying.
If "re-recordings" or "recordings that never happened" are of interest consider "Ray Sings, Basie Swings". In real life they never performed together but here they are back from the afterlife together on a CD. |
|
|
|
