Outlaw 950 - Audibility of speaker distance settings

Discussion in 'Archived Threads 2001-2004' started by Dzung Pham, Feb 18, 2002.

  1. Dzung Pham

    Dzung Pham Second Unit

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    Might I offer a suggestion to people who are concerened about the lack of speaker distance settings? If you have that capability on your current pre/pro or receiver, try changing them to what you would get with the Outlaw and see if you notice a difference. Set the subwoofer distance equal to the fronts (I assume this is what Outlaw would assume), and set the surrounds to their average distance value. I don't have this capability but would be interested in seeing if people that do have it notice much difference. It would be even better if you could grab a friend and do a blind test (double blind would be overkill) to see if you can tell which setting is which.
    If you do this, please report both your actual distances and tested distances. I would imagine that differences would be more noticable when the speakers are more irregularly spaced.
     
  2. John Tompkins

    John Tompkins Supporting Actor

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    Dzung, I have the denon 4802 and my front speakers are 11 feet left and 13 feet right from sweet spot.

    I accidentally set my front speakers to the same distance not knowing I had did it. As time went by{a couple of days} I KNEW there was something out of whack..specifically my music sounstage was off..

    I went threw all my calibration settings and discovered that the right speaker was set for 13 feet.

    People can say what they will, that is doesn't matter. I know in my system with my ears that it in fact DOES matter.
     
  3. Sankar

    Sankar Second Unit

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    I plan to do some testing over the next couple of days to find out what this means in my setting.

    btw John, I presume that even when you had improper distance settings, you had adjusted the volume levels correctly using a sound meter?
     
  4. John Tompkins

    John Tompkins Supporting Actor

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    Sankar, Yes I always had my volumes db by rat shack meter. My speakers never actually moved just my settings.

    I would suggest people try throwing there front soundstage out of time delay by two feet on either l/r speaker. Then throw on a couples of cds and a movie. I will bet you that you WILL hear a difference..
     
  5. Michael Mohrmann

    Michael Mohrmann Screenwriter

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    "btw John, I presume that even when you had improper distance settings, you had adjusted the volume levels correctly using a sound meter?"

    I believe that the volume levels (using test tones) are independent of setting the speaker distances/delays, at least as far as my Lexicon MC-1 was concerned. On the Lexicon processors, you set the speaker volume levels first, then the speaker distances/delays. Modifying the speaker distances/delays at a later time does not require the recalibration of the speaker volume levels.

    Michael
     
  6. Dzung Pham

    Dzung Pham Second Unit

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    John, I don't think most people are saying that it doesn't matter, I think they are saying that the effect is small. I could definitely see how the delay would have an effect on music and soundtracks with the front speakers. I am interested to see if the effect is as noticeable on the surrounds. I would guess that the effect is not as noticeable with movies but with real or simulated multichannel music, it might be a problem.
     
  7. Todd Hochard

    Todd Hochard Cinematographer

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    I don't think the effect is small at all.

    I can tell when the distance to the speaker is off by a few inches. How?

    It's very easy, actually. On AVIA, there is a test tone that plays an in-phase and out-of-phase tone rapidly between the left and center speakers. When it's in-phase, the sound should be located directly between the speaker. When it's out of phase, the sound should be "lost in the room." If the speaker positions, relative to each other, are off by more than two inches or so, the results are reversed.

    I was quite surprised by this, actually, and by using these tones to precisely locate my speakers, I've been able to greatly improve the precision of the soundstage. It's remarkable, actually. Try it yourself.

    On films, if set wrong, it sounds like hard jumps from one speaker to the next, instead of a smooth pan.

    Guy Kuo could probably give a much better explanation than I. I've heard the dramatic difference on my system, so I know look for the adjustments. It has given me pause on purchasing the 950.

    Todd
     
  8. Sankar

    Sankar Second Unit

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    Some very preliminary tests .. (more to be done):
    My "correct" settings:
    FL, FR and Center are at 12ft. (lucky me!)
    SR at 7 feet
    SL at 8 feet
    SBL and SBR at 14 feet each (yes, they are some distance behind me!)
    Sub : 7 feet (along the side wall at the 1/3 point a little behind me to the left)
    The sub signal goes thru a BFD which has been set to yield a pretty flat response from 20Hz to 80 Hz. I find that once I did this and set the level to match the left front, it automatically matched the other channels (AVIA tests) and also that it sounds fine for music and movies. (but I do reduce it for music by about 2db when the volume is raised)
    I used the Star Wars TPM disc .. the pod racing scene. Tried the following alternate settings:
    a) SR,SL,SBL and SBR set at 10 feet
    Changing the surround delays did not seem to matter much with this material. I will test it with T2 also (DTS-ES) later and see what it feels like .. any suggested scenes?
    and then
    b) Sub set at 12 feet
    However, changing the sub delay DID matter. The feel of the jets as they swooshed by you was more realistic with the correct distance setting .. with the improper settings, it all felt a little disjointed/disoriented. I am unable to put my finger on it .. but there was something definitely missing. I played the same scene a couple of times through each setting to be sure.
    Now this is not scientific whatsoever, and you will need to try it in your own setting, but in my case (and to my ears), the sub delay does appear to matter (but not so the surrounds). Unfortunately, the sub is one item that cannot be moved around so easily in the room! If you use the "fifths" or "sixths" rule and also take into consideration "cosmetic" and practical effects, you are often left with just one or two potential places for the sub -- which may or may not be at the same distance as the mains.
    I did not try playing with the delays on the FR and FL since I have the good fortune of having them at the same distance in my system. However, I will run this test, since I will be relocating soon (this summer) and there is no guarantee that the next house will have the optimum settings!
     
  9. Sankar

    Sankar Second Unit

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    Just a question to follow up on my earlier message ..

    Since the surround delay does not appear that critical but the same cannot be said for the sub, is there any product that we can use to induce a delay into the sub channel? If so, then this could be something we could just add on (and one channel is enough!) between the pre-pro and the sub (or in my case, between the BFD and the sub).

    This could eliminate at least this one issue completely.
     
  10. John Tompkins

    John Tompkins Supporting Actor

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    Sankar, thanks for the test, I hope you will also do your front L/R test. I beleive you will be amazed at the differences there. Not trying to beat a dead horse, but lets just say I will be following this thread very closely.
    Also as far as demo scenes for the rears, I would think something like Gladiator{where he's swinging that ball/chain around the room. Air force one{jets circle around }. Dragonheart{draco flying} etc. would do nicely.
    My wife says size dont matter, but time alignment does[​IMG]
     
  11. John Tompkins

    John Tompkins Supporting Actor

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    {quote}

    Guy Kuo could probably give a much better explanation than I. I've heard the dramatic difference on my system, so I know look for the adjustments. "

    I also remember reading a very interesting post by Guy on time alignment issues but I am unable to find it. Maybe Guy will drop by and post or somebody else has read it and knows where it is at ??
     
  12. Sankar

    Sankar Second Unit

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    John,
    I will definitely do a test with the fronts as well, since this could become an issue once I move out of my current house.
    Unfortunately I do not have either the Gladiator, Air Force One or Dragonheart [​IMG] .. I do have TPM, Shrek, T2 and all the Star Trek movies .. any scenes in these movies?
     
  13. John Tompkins

    John Tompkins Supporting Actor

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    {quote} Unfortunately I do not have either the Gladiator, Air Force One or Dragonheart .. I do have TPM, Shrek, T2 and all the Star Trek movies .. any scenes in these movies?
    Sankar, the first thing you need to do is go on down to best buy and pickup these 3 movies[​IMG] Just kidding, but they are great sounding movies..
    Shrek would be my last choice as theres hardly any surround effects at all to speak of..TPM is probably your best choice,pick a scene where the surrounds play in a sequence instead of all at once...
     
  14. Dzung Pham

    Dzung Pham Second Unit

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    Sankar, thanks for your testing. I've changed my mind a bit about this issue and now think it's pretty important (although fortunately, my system is fairly symmetric so most of the issues don't apply). Can you test out DPL2 with music and see if you notice a difference on the surrounds?
    John, was this the thread about time alignment you were looking for? Pretty interesting reading.
     
  15. Sankar

    Sankar Second Unit

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    John:
    Maybe this is the excuse I can use to pick up all those movies!!
    If I cannot find a suitable scene, maybe I'll just pop over to Blockbuster and rent a copy of Gladiator. Does anyone recall how far in the movie this particular scene is (where he's swinging the ball and chain around the room)?
    Dzung:
    Unfortunately I have a Denon 3801 which does not have DPL2 [​IMG] I could try DTS Neo, if you wish. I was planning to try Eagles:Hell Freezes Over (DTS) for the music test. I'll also do some 2 channel tests for the sub delay.
    My room is about 18 ft by 26ft, so the difference between the sub and main spkrs are significant. I suppose that in smaller rooms (e.g 10x15), these differences in delays etc are far less important.
     
  16. Lewis Besze

    Lewis Besze Producer

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    Denon users should use the "meter" setting over "feet",as it's increments is finer.0.1 m[10cm]as oppose to 1 feet[@30cm].

    And yes my experience is that the sound field is more coherent,and tighter.

    Also monopole surrounds benefitting of this a little better then dipoles IMO.For subs o yeah it's a must!
     
  17. Sankar

    Sankar Second Unit

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    Excellent point Lewis! I will need to go back and set everything using "meters". However, for this current test (till I have measured it all precisely in meters), I shall continue with my measurements in feet (just for consistency with the earlier post).
    I did a test to see what the delays did to pure 2 channel music.
    • The dvd was the DTS Demonstration DVD #4.
    • The track I chose was Sheryl Crow's "Am I Getting Through".
    • I used the PCM Stereo signal from the dvd, and played the piece using the "Direct" mode on my 3801. Its my understanding that this bypasses all processing.
    • My setup is a Denon 3801 used as a pre (none of the amps in the unit are being used). An AT1504 amp powers my Infinity Overture 3 towers in bridged mode. I also have an Infinity HPS1000 sub .. a BFD is in the signal path of the sub to flatten out room induced peaks. An AT1505 powers my Infinity CC3 center and 4 Infinity QPS1 surrounds. An AudioControl Rialto is also employed on the center and surrounds to ensure that they are tonally balanced with the mains (which I did using pink noise and SpectraPlus).
    Rather than go through the song in its entirety, I focussed on the initial minute or so. There is a fair amount of subtle detail in the passage and there are sounds that move across the stage sideways and front to back. I concentrated on these details and also on how the bass felt (the bass guitar comes in and is the highlight in the beginning).
    Instead of physically moving the speakers (and not changing the delay), I chose to leave the speakers where they were but to change the delay settings instead. This way I did not need to recalibrate the volume levels of the speakers at every stage. I think that the qualitative results of physically moving the speakers (with no change in delay, but compensate the volume levels) will be the same as changing the delay (and leaving the speakers where they were). An added benefit of just adjusting the delay is that the volume at which one hears the different passages is unaltered through the entire experiment.
    I first played the passage using the correct delay for the speakers (FR and FL at 12 feet) to get a sense of what it all feels like.
    I then changed the distance specs of the FL to 5 feet to get a sense of one extreme (i.e. about 7ms delay). The effects were dramatic! The soundstage shifted towards the right speaker -- not quite what I'd expected at first, but it makes sense once you think about it. (Basically the FL was being delayed relative to the FR, but since the distances were the same, the sound from the FR reaches the ear first). It was as though the stage was concentrated on the right half (between my center speaker, which was of course silent, and the FR). There were sounds coming from near the left end of the stage, but the predominance of effects were on the right half. When sounds panned across the stage, it felt as though they moved from the right end to the center somewhat smoothly (i.e. across the compacted soundstage) and then very quickly moved from the center towards the left speaker. All details at the mid and high end of the spectrum were still in the music (so to someone listening to it for the first time, it would sound "ok"), but the compacted soundstage was clearly apparent. The bass field was also significantly altered. Bass lacked a "fullness" to it .. sounded somewhat clipped and not as smooth. Interestingly, the shift to the right was more pronounced for lower frequencies than for the higher ones. Finally, the stage lacked 3 dimensionality (i.e. "depth"). When properly calibrated, I could easily pick out the instruments near the front of the stage and those near the rear. With the improper delays, it became harder to differentiate between these.
    Anyone who doubts these effects should try it on their own system .. its an easy test and illustrates the effect of delays on the soundstage.
    To confirm symmetry in these effects, I then changed the distance setting of the FL to 19 feet. Exactly as predicted, the soundstage shifted to the left and stayed in the left half of the full stage. In addition, as before, bass lacked fullness. Every effect was a mirror image of the first one.
    Third, I tried changing the distance setting of FL to 9 feet (basically a 3ms delay since the FR was at 12 feet). The "hole" that was created in left half of the soundstage was not as pronounced, but now that I knew what to look for, it was definitely there. Finally, I set everything back to normal and verified that the stage was as it should be.
    This little experiment has convinced me that delays do indeed matter in determining the size and quality of the soundstage in my setup. Admittedly its not a blind test and I knew which setting was which. However the results were sufficiently dramatic that I'm confident that I could've identified these variations blindfolded! Please feel free to flame me here [​IMG], but I strongly suggest that you try this if you have never done so before. It was rather illuminating to me. It could well be the case that with a better quality pre-pro these effects will go away and that I noticed these since I do not have a high level pre .. though I very much doubt it since I'm unable to conjure up any scientific basis for that conclusion.
    I have not experimented with the rear surrounds vs side surround issue (partly because I do not have a good source dvd to check this yet). I will try it soon, but in the meantime, I must admit that my priors have been altered. If there was such a difference in the front soundstage, why should there not be a similar impact in the side/rear? It may not be noticeable most of the time with "usual" material ... but what about the occasional soundtrack where it does?
     
  18. BruceD

    BruceD Screenwriter

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    Sanker,

    Since stereo receivers generally have balance controls, it would seem interesting to simulate balance controls by changing the volume between Left and Right front channels and see if it produced the same effect as the different time delays.
     
  19. Sankar

    Sankar Second Unit

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    BruceD,
    I guess that the net effects of the time delay and balance, in terms of what they do to the sound stage, are similar (though not identical, since the delay affects different frequencies differently while the balance affects all frequencies identically).
    However, it would be difficult to compensate for the improper time delay using the balance. Basically each channel's volume level was independently set using a sound level meter to ensure that the output was identical. Hence even with the delays, the volume put out by the 2 speakers were probably similar. To compensate for the improper delay, one would have to adjust the balance using some music -- and I'm not even sure that the amount of compensation will be universally true for all passages. I somehow suspect that this will be an exercise akin to stuffing toothpaste back into the tube [​IMG] !
    Finally, the desirability of such a correction would be somewhat questionable. Basically in order to correct for an improper delay setting we would be introducing an improper volume level setting.
     
  20. John Tompkins

    John Tompkins Supporting Actor

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    Sankar, The review of your findings was very well defined and most useful imformation!

    I'm so glad somebody else actually got off the forum and went to his system to try this test..Thanks again for posting your findings.

    DZUNG, I just noticed the thread link you provided about time alignment, YES that is the thread!!, VERY INTERESTING
     

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