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The front soundstage -- enveloping you? Not quite getting it.

Discussion in 'Archived Threads 2001-2004' started by Michael R Price, Apr 17, 2002.

  1. Michael R Price

    Michael R Price Screenwriter

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    I have heard from many places that a properly set up 2 channel system can deliver sounds that you hear from a full 180 degree range (out to your sides).

    In short, I can't get this to happen. I'm trying to think what is going on that enables us to hear sound from 'outside' the speakers, or even between them. What's happening is our brain is correlating the difference in tone and phase between the same sound coming to two different ears, and then using that to determine where the sound came from. I can understand that. But how do we recreate a sound outside the pair of speakers? Is the signal in one speaker ridiculously out of phase with another?

    I have Kit281 speakers, which have excellent imaging. When I had the tweeters facing to between the speakers (they are asymmetrical, the tweeter is on one side and each speaker is opposite of the other) I occasionally heard certain parts of music coming from just outside the speaker (nothing major though). After reading a comprehensive review with measurements, I decided to switch the left and right speakers. Something else about the sound improved, but now there is no "extra-speaker" sound. (Note: the soundstage still has excellent depth and there's some sensation of 'height' which I don't exactly understand but it's really quite realistic somehow.)

    I find myself now moving my chair closer up and sitting 4-5 feet away with a 90-100 degree spread (instead of 7 feet and 60 degrees.) Still no wraparound effect but I think I like the 'size' better. You know, when you close your eyes and relax and you're almost in the band. I've also played with the toe in angle of the speakers and can't tell what I want. Pointing them away from me makes the sound a bit duller but it's easier on the ears at high volumes. And it does nothing to the soundstage.

    Does this have to do with the recording? The phase response of the speaker? My other equipment? What could be going on here?

    I apologize for the long post. This is a very interesting topic for me. Thanks for the help.
     
  2. Steve_Ma

    Steve_Ma Second Unit

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    Michael,

    I'm very interested in what others have to say. My gut tells me that the omnidirectinal effect will ultimately have to do with a number of factors. I believe that the proper blending of the bass and the volume has something to do with this. The bass line of most my preferred music really "draws me in" and since a great deal of this bass is omnidirectional, I have to think this contributes. When listening to music (2.1 ch), with my sub dialed in and the volume around 75db +/-....this is when I am most suceptible to....not being sure if I accidentally switched to 5.1 ch mode. I sometimes will walk up to my center or surrounds to be sure I didn't switch DSP modes by accident. A lower volumes, I do not seem to exp this.

    My system is calibrated with all channels at the same levels and I am forced to do all near-field listening (about 7-8 ft from the mains) due to room constraints.

    That's my $.02

    --Steve
     
  3. Michael R Price

    Michael R Price Screenwriter

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    Thanks for the reply Steve. Well I don't have either center or surround speakers. Center imaging, anything at or inbetween the speakers, is great. In fact there's even depth in it when the sound is all the way to the left or right (its like the sound is coming through the back of the speaker). But what I'm concerned about is sound to the sides. It's just not there and I do think I have a reasonable system.

    Don't have a sub, but the 281s do have a very good bass response (strong to 20Hz using sine sweep but the standing wave modes are terrible, 15db dip at 60Hz and a few other big anomalies... it's a bit better when I move closer in.) Of course, medium volumes and up the bass does seem to 'surround' me and vibrate me from all directions, but I'm talking more about the precise reproductions of instruments and things. Or am I misunderstanding something, why would the bass have anything to do with the soundstage?
     
  4. Steve_Ma

    Steve_Ma Second Unit

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    NP, I wish I could be more help. I assumed you were talking about 2 channel listening. I mentioned my surrounds/center as an example. Someone else jump in here, I'm drowning!
    I'm not SURE the bass does add to this. I was thinking/typing out loud. There was certainly more than alittle supposition in my last post [​IMG]
    I guess my point is that if my sub is not dialed in right or if one of my mains has been moved and is in need of recalibration , the music just seems alittle TOO directional for me. The change in the soundfield I've grown accustomed to becomes apparent. It becomes too easy to pick out what sounds are coming from which speaker, rather than blending to form a uniform presentation.
    --Steve
     
  5. ling_w

    ling_w Second Unit

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    The way a beyond speaker sound is recorded and reproduced usually entails either the modification of the sound source by our ear/head. Or it involves playing around with the phase relationships between what is produced by the left and right speaker. In a crossed figure 8 mic setup, extreme left sound source would cause the right mic to pick up the info out of phase, so the right speaker would play it back out of phase.

    If your speakers are not phase linear in the in the freq below 2khz, it might alter the phase of the sound source enough for that illusion to disappear. It might also be because of strong side wall reflections.

    That is also one of the reason that multi-channel music is bogus (pretty much all the multi-miked music also.) They do not take into account of the interaural time difference (in addition to interaural level difference) when hearing live music or any other sound source. Only Ambisonic recordings reproduces the ILD and ITD that exists in the original performance. It has many other advantages also like storing music information in directional and intensity vectors instead of 2.0, 5.1, 7.1 or 10.3. Decoupling of number of recording and playback channels (playback could be 2,3,4,5,6,7...32 channels.) Periphonic recording/playback (3-D) utilizing only 4 carrier channels....
     
  6. Manuel Delaflor

    Manuel Delaflor Supporting Actor

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    Have you listened to some records that use DSP technologies? For example, Madonna have one recorded with "Q Sound", you can find more info and other recordings in their site. DSP technologies can do what you want; proyect sound beyond the speakers "boundaries", and the effect can be quite impressive.
    Another way to achieve similar results is to buy a DSP processor, like the little Wow Thing (which I own) from SRS Labs:
    http://www.srs-store.com/store/mall/spc_wt.asp
    There are another products, like this ones:
    http://www.progressive-concepts.com/33.html
    In fact, I will buy one of them, I definitely love DSP technology.
     
  7. Hanwook_K

    Hanwook_K Stunt Coordinator

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    Have you played with distance between the speakers. The more you pull them apart the more spacious it sounds, but at somepoint you loose all imaging. The other thing is room acoustics. Do you have a lot of stuff in your room - carpet, curtains, couch, bookshelves etec can have an effect of the "liveliness" of the recording.

    Also what kind of speaker stands are you using? (I'm not familiar with the model) Are they solid? Make sure they don't reasonate at loud volumes.

    Just some thoughts ...
     
  8. matthew_rm

    matthew_rm Second Unit

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    Isn't nuance Q-sound? BLAH!
     
  9. Saurav

    Saurav Cinematographer

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  10. Bob_L

    Bob_L Supporting Actor

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    Bob Lindstrom
    In my experience, two-channel stereo CAN recreate a remarkable simulation of 180-270 degree soundfields. Particularly if you're listening from the "sweet spot."

    However, it is also the case that a lot of popular music recordings consist of many, many "mono" tracks that are overdubbed and panned to create a soundfield. (I'm simplifying and overstating the case to make a point, I admit.) Mixing in a little digital processing or reverb isn't enough to add those little 3D audio clues that make the ear hear those full, wide and enveloping soundfields.

    So, no wonder that so many new recordings are locked into the speakers and rarely create a big stereo ambience.

    Even so, if you can find a recording engineered to create an acoustical ambience, or a high quality live recording (where it's harder to avoid creating a real world acoustic), a good stereo playback can make you run over to the surround speakers to make sure they AREN'T turned on.

    PS -- Your sound system can also compromise imagery quite a bit by "swallowing" those little 3D "clues" in the recording. I recently replaced my front speakers amp -- a Carver 705x, which wasn't chopped liver -- with an Aragon 8008x3. The Carver gave a great, wide soundfield and I was very pleased with it.

    But the Aragon creates even a WIDER soundfield that reaches right into the room and with even greater detail. In fact, sometimes a solo vocal will seem to be positioned in the middle of the room IN FRONT of the NHT 2.5's. The effect is pretty startling and very convincing.

    I wouldn't have thought that there was that much improvement to be had in stereo playback in my room and my system. But, boy, was I wrong.
     
  11. Harold_C

    Harold_C Stunt Coordinator

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  12. Kerry Hackney

    Kerry Hackney Stunt Coordinator

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    A lot has to do with speaker placement and a second large issue is source material. I also have the 281s in a vented allignment. I also have the luxury of some room to experiment with speaker placement. I currently have them setup with the tweeters to the outside of center, they are pulled out about 35" to the front baffle from the rear wall, 12' apart and angled in just slightly. I like them better if they are not pointed at the sweet-spot. My trade-off is that I have a large entertainment center in between them. The fronts of the speakers are in front of the face of the cabinet. At the extreme with source material with Q-Sound / Madonna's Music and Immaculate Collection the surround effect with 2 channel is amazing. The sound will absolutely travel in a 360 degree arc around the listening position on one track from IC. Yes, it will actually sound like it is BEHIND you.

    For NON Q Sound recordings, I find vocal albums like James Taylor, Jane Monheit to be pretty revealing. The vocals will be dead center, and with JT you can hear that the guitar he is holding is lower in space than the vocal. I will search my CDs and give you some specifics for sounds that eminate from farther to the sides than the speakers. I do have several that produce this effect. Conversely, I have some CDs that just don't have any imaging to speak of. The drums, guitars whatever just sound like they are coming from the speakers. Very "boxy" sounding. But, I know this is due to mastering. I have spent much of the last 3 months experimenting with placement and trying to become a better listener. I have resorted to making written notes about given tracks because I don't trust my memory when trying to compare the same song maybe a week apart.

    In general, I think the 281s like to have some space around them, don't be afraid to set them far apart and above all, experiment. Placement is time consuming, but it is free. You owe it to yourself to get the most out of these speakers, they really can be very, very good.
     
  13. Manuel Delaflor

    Manuel Delaflor Supporting Actor

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    "The subtle "ambience" cues are the first thing that goes in this process as the digital compression schemes interpret such sounds as "inaudible" and chuck them"

    This depends on the method they use. Actually most digital processors are based on Psychoacoustics research, and the ambience cues are included to make our brain feel space between and around the instruments.
     
  14. Manuel Delaflor

    Manuel Delaflor Supporting Actor

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    Kerry,

    I agree with you. I have done the same, I passed several weeks experimenting with location, thankfully, this is a room my wife "don't care about", so I can do whatever I want to make my system sound better!

    Anyway, after lot of changes, sometimes just an inch or two in the toe in, sometimes a bit higher or lower, etc. I have reach a location that creates almost holographic imaging with some recordings.

    It is trully amazing to open your eyes and note how they contradict what your ears are telling you...

    By the way, Im experimenting with an SRS Labs device, it is a litle piece of hardware called "Wow Thing", and it draws an effect similar to the Q-Sound. All I can say is that (again, with some recordings) it improves further my already impressive imaging and soundstage.
     
  15. Michael R Price

    Michael R Price Screenwriter

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    Thanks for the replies, I've been away a little while.
    I think my experiences match up with yours. I just listened to the recent CD by Incubus (rock music, a bit 'heavier' than most of what I like). At the start of the first track 'Nice to Know You' there's this 'ambiance' sound 'hoooo... hooo' (sorry, hard to describe). At first it just seemed like the sound was panning from left to right and back. Then I closed my eyes and realized the sound was really floating around in space behind me. No joke. So I'm thinking the problem isn't really my speakers or anything, but that many of my CDs just aren't recorded that way. Can't win can I? [​IMG]
    Kerry, I have noticed the 'guitar below vocal' effect. And also that bass stuff (amps, drums whatever) tend to be lower down (on floor?), vocals are medium height and other sutff is... everywhere. Plus you can hear the singer's voice 'layered' over another singer or instrument directly behind them. Pretty neat huh?
    Due to my room (furniture reflections and especially bad bass response) I find myself listening more 'near field' with myself and the speakers all in the middle of the room (maybe 5 feet from them, they're 6 feet apart). And it sounds awesome. There's usually much more going on in the center 80 degrees of the soundstage anyway.
     

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