• 05-04-2009, 08:22 AM
    manlystanley
    So What is "3 Dimensional Imaging"?
    I was listening to my system today and I was astonished that I could hear the cello being played lower, while I heard the flute playing as if the player was standing (e.g. much higher). In other words, my B&W 684 speakers imaging gave both a sence of lateral position and horizontal as well.

    I've read that some speakers are better then others at 3 Dimensional Imaging, but I'm not quite sure what it is.

    -- Is it being able to perceive players standing or sitting?
    -- Of it is being able to tell that the drums are further back?
    -- Or is it something else?



    Thanks for the help,
    Stan
  • 05-04-2009, 08:34 AM
    mlsstl
    "3 dimensional" is simply that - the ability to place objects in all three dimensions in space: 1) left to right, 2) top to bottom and 3) front to back.

    This is heavily dependent on the quality of the recording. Unfortunately, many recordings these days are primarily artificial contrivances done on a mixing console. However, in the hands of a good engineer, quite convincing illusions are possible.

    The other thing you need is a very stable balance between the left and right speaker. Both should be as close to each other in frequency response and other characteristics as possible. That's why many of the better speakers are sold only in factory matched pairs.

    A good room setup is also important. Room reflections that are inconsistent from side to side can screw up a good stereo image.

    A good recording on a well setup stereo can be quite eerie.
  • 05-04-2009, 10:46 AM
    RoadRunner6
    Quote:

    Originally Posted by mlsstl
    "3 dimensional" is simply that - the ability to place objects in all three dimensions in space: 1) left to right, 2) top to bottom and 3) front to back.

    This is heavily dependent on the quality of the recording.

    Excellent point about the recording. Lots of credit is given sometimes to amps, source components, cables, speaker wire, etc but perhaps the speakers and their relationship to the room are the most important factor other than the actual quality of the sound source like Mlsstl states.

    When listening for precise comparisons of the imaging/soundstage on different speakers it is important to be sure they are in the same room/location/equipment and playing the exact same (hopefully high quality) source.

    RR6
  • 05-04-2009, 12:13 PM
    Auricauricle
    Interesting point about the "matched pairs" issue re speakers, misstl. Does this mean that some speakers are made as a duet, instead of in mass-production assembly lines, etc.? Does this mean, one craftsman or one team of craftsmen work in concert on a pair, keeping all things QC related and otherwise uniform?

    Velly intellestink!
  • 05-04-2009, 01:19 PM
    mlsstl
    Quote:

    Does this mean that some speakers are made as a duet...
    It doesn't really mean they are made as a pair, but that they are tested after a production run. Let's say a quality control parameter allows a +/- 1 dB deviation from the manufacturer's design goal. Take two speakers with one up 1 dB at 1 KHz and another down 1 dB at 1 KHz. Both meet the manufacturer's standards, but they would not be a good pair to match up together since the relative deviation between them is now 2 dB, not 1.

    If a consumer had that pair, he might find the stereo image less precise or perhaps wanders about more than if the speakers were a closer match.

    By making the best match between pairs of speakers after a production run the end user gets better performance without dramatically raising production costs.
  • 05-04-2009, 01:31 PM
    Auricauricle
    The things one learns...!
  • 05-04-2009, 04:16 PM
    Kevio
    3-dimensional imaging on a stereo setup is the illusion that you're hearing things in three dimensions. With only two channels the only direct information you have is side-to side location. A fine listening room and equipment gets out of your way and allows you to imagine three dimensions.
  • 05-04-2009, 05:26 PM
    E-Stat
    What he said!
    Quote:

    Originally Posted by mlsstl
    "3 dimensional" is simply that - the ability to place objects in all three dimensions in space: 1) left to right, 2) top to bottom and 3) front to back.

    Well stated. An exceptional recording on an exceptional system is able to make the walls disappear and fool you into thinking you are in a far greater space. Just like looking through a GAF viewer.

    rw
  • 05-05-2009, 04:07 AM
    manlystanley
    Quote:

    Originally Posted by mlsstl
    It doesn't really mean they are made as a pair, but that they are tested after a production run. Let's say a quality control parameter allows a +/- 1 dB deviation from the manufacturer's design goal. Take two speakers with one up 1 dB at 1 KHz and another down 1 dB at 1 KHz. Both meet the manufacturer's standards, but they would not be a good pair to match up together since the relative deviation between them is now 2 dB, not 1.

    If a consumer had that pair, he might find the stereo image less precise or perhaps wanders about more than if the speakers were a closer match.

    By making the best match between pairs of speakers after a production run the end user gets better performance without dramatically raising production costs.


    Well, mIsstI, You answered both my question about 3 dimensional imaging *AND* why I need to set my left speaker for 1db additional gain. Thanks so much!
  • 05-05-2009, 05:44 AM
    Auricauricle
    So how would one compare 3-dimentional Imaging to Holographic Imaging (Carver, e.g.)?
  • 05-05-2009, 08:50 AM
    mlsstl
    Given the bent of this topic, I thought the following might be interesting to all concerned.

    Stereo perception in hearing is a complex subject for no other reason than the human brain is a complex organ. However, there are some fundamental cues that we use to hear stereoscopically. (The word "stereo" is from the Greek "stereos" which means "solid" as in a three dimensional image.)

    We hear in stereo and it is the difference in sound between the left and right ears that allows our brain to determine a sound's position in space relative to us and the distance from us.

    Our ears are sensitive to:

    1) relative loudness between left and right. This is also affected by frequency response. A sound may be equal in volume at lower frequencies, but above roughly 1500 Hz, the high frequencies will be "in the shadow" for the ear furtherest from a left or right position.

    2) relative phase. The brain is sensitive to phase differences in the range of 100 Hz to 1500 Hz (which includes the fundamental frequencies of the human voice) so we perceive the phase difference in the sound wave between the left and right ears.

    3) arrival time differences. The maximum time difference between a sound source that is directly in front of us and 90 degrees to one side is about six ten-thousandths of a second. The brain locks on to the initial arrival transient to determine location.

    4) tonal balance shifts. The ear canal does not convey a "flat" frequency response to our ear drum. Our ear drum receives more high frequency info when the sound is above our head than below due to the shape of the ear lobe. This can give height indications and is also used for in-front of us vs behind-us detection.

    5) the mix of direct to reflected sound. When we are closer to a live sound source, we receive more direct sound than reflected. As we move further away, the percent of reflected sound increases and the high frequencies also drop off. Also, reverb and echos can add a sense of distance and give a sense of a room's space and size.

    All of these paramenters can be manipulated or generated artificially in a recording studio. In the hands of a good engineer, the illusions can be quite realistic and convincing.
  • 05-05-2009, 11:39 AM
    mlsstl
    Quote:

    So how would one compare 3-dimentional Imaging to Holographic Imaging (Carver, e.g.)?
    As I understand the old Carver literature, their Holographic circuits were a way to reduce "interaural crosstalk" in a way that ostensibly cleaned up the secondary sonic "arrivals" coming from the opposite speaker in your stereo.The goal was to more accurately portray the recording, not to add pleasant "enhancements."

    I only heard the thing once, well over 20 years ago and wasn't overly impressed though I didn't think it was bad. I fell into the camp that believed it introduced more artifacts than it fixed. For whatever reason, it never took off with the public. It still has a small group of followers to this day, however.
  • 05-05-2009, 04:29 PM
    JoeE SP9
    Try this recording
    Jacintha Here's To Ben Groove Note GRV1001-2

    A properly set up system will throw a 3D sound stage when playing this recording. When I play it the walls around my speakers disappear. The impression of a large room "over there" with Jacintha standing centered and in front of musicians playing live in that large room is what it sounds like to me on my system. I have heard it played on other systems that have varying degrees of the 3D effect. The better the system the better the disappearing act of walls and speakers.

    It's an analog recording that may still be available as a new LP. It was recorded live to two track tape running at 30IPS. The CD is labeled as 24 bit and the recording (CD&LP) was mastered by Bernie Grundman.
  • 05-05-2009, 05:09 PM
    Auricauricle
    Years ago, I bought a Carver Hologram Generator for a couple of Klipsch Heresies that were hooked to a Yamaha C2a and M2. No difference with it on or off....It went back the next morning. Later, a friend told me that horn loaded speakers were less apt to be affected. Nodding towards his Tannoy SRM's, he indicated that coaxial speakers would benefit and why the heck did I return the thing?

    Well?
  • 05-07-2009, 08:38 AM
    manlystanley
    Hello mlsstl,
    This is fascinating. It now makes sense how speakers can be engineered to provide 3 dimensional imaging. They provide little nuances that our brains pick up to determine location. It sounds like a real art.


    Thanks for the information!

    Best Regards,
    Stan



    Quote:

    Originally Posted by mlsstl
    Given the bent of this topic, I thought the following might be interesting to all concerned.

    Stereo perception in hearing is a complex subject for no other reason than the human brain is a complex organ. However, there are some fundamental cues that we use to hear stereoscopically. (The word "stereo" is from the Greek "stereos" which means "solid" as in a three dimensional image.)

    We hear in stereo and it is the difference in sound between the left and right ears that allows our brain to determine a sound's position in space relative to us and the distance from us.

    Our ears are sensitive to:

    1) relative loudness between left and right. This is also affected by frequency response. A sound may be equal in volume at lower frequencies, but above roughly 1500 Hz, the high frequencies will be "in the shadow" for the ear furtherest from a left or right position.

    2) relative phase. The brain is sensitive to phase differences in the range of 100 Hz to 1500 Hz (which includes the fundamental frequencies of the human voice) so we perceive the phase difference in the sound wave between the left and right ears.

    3) arrival time differences. The maximum time difference between a sound source that is directly in front of us and 90 degrees to one side is about six ten-thousandths of a second. The brain locks on to the initial arrival transient to determine location.

    4) tonal balance shifts. The ear canal does not convey a "flat" frequency response to our ear drum. Our ear drum receives more high frequency info when the sound is above our head than below due to the shape of the ear lobe. This can give height indications and is also used for in-front of us vs behind-us detection.

    5) the mix of direct to reflected sound. When we are closer to a live sound source, we receive more direct sound than reflected. As we move further away, the percent of reflected sound increases and the high frequencies also drop off. Also, reverb and echos can add a sense of distance and give a sense of a room's space and size.

    All of these paramenters can be manipulated or generated artificially in a recording studio. In the hands of a good engineer, the illusions can be quite realistic and convincing.

  • 05-11-2009, 08:03 PM
    JoeE SP9
    mlsstl: I've never heard any multitrack studio recording that sounds as realistic as any Direct-to-Disc recording or the Jacintha I recommended. Although there is always a nice left right spread there is almost no depth information. If you are aware of any "studio" recording that has some real depth, please let me know. I'll buy it and give it a listen.

    Studio being your standard multitracked, overdubbed, EQ'd and processed CD.
  • 05-12-2009, 05:04 AM
    Kevio
    Try Kiko by Los Lobos. Lots of fun with ambiance effects and hard-cranked pan controls. Close your eyes and enjoy.
  • 05-12-2009, 05:42 AM
    Feanor
    Subtle clues
    Quote:

    Originally Posted by mlsstl
    Given the bent of this topic, I thought the following might be interesting to all concerned.

    Stereo perception in hearing is a complex subject for no other reason than the human brain is a complex organ. However, there are some fundamental cues that we use to hear stereoscopically. (The word "stereo" is from the Greek "stereos" which means "solid" as in a three dimensional image.)

    We hear in stereo and it is the difference in sound between the left and right ears that allows our brain to determine a sound's position in space relative to us and the distance from us.

    Our ears are sensitive to:

    1) relative loudness between left and right. This is also affected by frequency response. A sound may be equal in volume at lower frequencies, but above roughly 1500 Hz, the high frequencies will be "in the shadow" for the ear furtherest from a left or right position.

    2) relative phase. The brain is sensitive to phase differences in the range of 100 Hz to 1500 Hz (which includes the fundamental frequencies of the human voice) so we perceive the phase difference in the sound wave between the left and right ears.

    3) arrival time differences. The maximum time difference between a sound source that is directly in front of us and 90 degrees to one side is about six ten-thousandths of a second. The brain locks on to the initial arrival transient to determine location.

    4) tonal balance shifts. The ear canal does not convey a "flat" frequency response to our ear drum. Our ear drum receives more high frequency info when the sound is above our head than below due to the shape of the ear lobe. This can give height indications and is also used for in-front of us vs behind-us detection.

    5) the mix of direct to reflected sound. When we are closer to a live sound source, we receive more direct sound than reflected. As we move further away, the percent of reflected sound increases and the high frequencies also drop off. Also, reverb and echos can add a sense of distance and give a sense of a room's space and size.

    All of these paramenters can be manipulated or generated artificially in a recording studio. In the hands of a good engineer, the illusions can be quite realistic and convincing.

    In speaker reproduction items (3) and -- hopefully -- (2) don't apply. Item (5) is highly dependant on you own listening room environment. In that regard, imaging will always improve if room relections are reduced, especially "early relections", those that come from the first "bounce" of the sound off walls, floor, or ceiling.

    A sense depth, I'd guess, depends on items (4) and (5) which depend almost entirely on the recording. That is, the record sound spectrum and recorded arrival times & reflections should be varied slightly in a way that mimics the these differences in a real concert hall. You rarely get this if the recording engineer has used close-micophoning techiques.

    I speculate the the sense of height is also related to items (4) and (5). That is, instruments or voices will sound higher that also sound farther way -- this is trick of the brain since all the actual sound from the speaker is on the same plain.