Front 3 speakers test tones should they be identicle (H/K 520)

Discussion in 'AV Receivers' started by RickBlacker, May 11, 2003.

  1. RickBlacker

    RickBlacker Stunt Coordinator

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    I have a Harman Kardon AVR-520, I have noticed that when I do my test tones to adjust speaker levels the center speaker does not have the exact same test tone as the left and right channel. Simply, it does not sound exactly the same.

    I have the Klipsch R7 series of speakers and I expected that through the RC7. However, I always thought that the difference in test tone sound was because the center was simply a different speaker all together. However, I recently purchased my center RC7 with another front speaker the RF7 which make my front 3 speakers identical. So now, my left, center and right speakers are all RF7s.

    Once hooking up the new RF7 center, I thought I would hear 3 identical sounding test tones from the receiver across the three fronts, but that is not the case. I still hear a different sounding center channel.

    Is this by design, are all receivers like this, or do I have a defective unit? If it's bad, then it has been bad from day 1 and I have never know it.

    One thing also I would want to mention, the speaker wire for the center is NOT as long as the two fronts, and all 3 front speakers are bi-wired.

    Any help to clarify this would be most helpful! :b
     
  2. Tim Hoover

    Tim Hoover Screenwriter

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    In my experience, it's usually the slight difference in placement. I have five identical speakers all around (nOrh 4.0s) and have noticed the same thing that you're experiencing - especially across the front. My front mains are about two feet from the back wall and 1.5 feet from the side wall, slightly toed-in. The center is, due to HT layout, only about 1.5 feet from the back wall. This gives it a slightly boxier sound.
     
  3. RickBlacker

    RickBlacker Stunt Coordinator

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    If it is placement, what can I do to make is sound more like the front two? Bring it forward a bit?
     
  4. Tim Hoover

    Tim Hoover Screenwriter

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  5. Scott Simonian

    Scott Simonian Screenwriter

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    Also, the location of the speakers in the room can have differnt frequency responses. On the left and right sides may have non-flat rsponces at the listening position; while the center is. It may be the other way around.

    Maybe some variances is the RF7s fr is to blame? I dont know. I like the sound of Klipsch speakers myself but I know they usually dont have ruler-flat frequency response.

    Eh. Ill look at my 525.
     
  6. Henry_W

    Henry_W Stunt Coordinator

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    I think placement is the issue as well. the midrange stuff through the horns are probably reflecting strongly off the fronts if they are near corners, resulting in an impression of more volume (in certain frequencies) at your sitting area. I have heresy all around and found that I had to slightly toe the fronts and then level adjust the center to get it right. I assume the HK gives you the same capability as my reciever.
     
  7. RickBlacker

    RickBlacker Stunt Coordinator

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    ================================================== =========
    Scott Said

    Also, the location of the speakers in the room can have different frequency responses. On the left and right sides may have non-flat responses at the listening position; while the center is. It may be the other way around.

    Maybe some variances is the RF7s fr is to blame? I don't know. I like the sound of Klipsch speakers myself but I know they usually don't have ruler-flat frequency response.

    Eh. Ill look at my 525.
    ================================================== =========


    Scott...

    My RF7s R/L are toed in slightly. The front of the speaker is within a foot of the wall as well as the rear. I have been toying with the idea of putting a reflection absorber to the side of the fronts where the very first reflection would occur. I had a friend stand against the wall once right where the first reflection would occur, when doing that, he pulled the sound of the speaker more into the center. I wonder if that would help the dialog.

    Also, I was given advice last night to set my center speaker to small. I definitely going to try that tonight to see if it helps with dialog as well as play with positioning my center speaker.
     
  8. Bill Cowmeadow

    Bill Cowmeadow Second Unit

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    Put all three speakers together in a cluster in the center. If they sound the same, problem/perception solved. if they still sound distinctly different, then so-be-it, that's just the way your rec. handles the center channel pink noise.

    This hobby can drive a person nuts.

    Bill
     
  9. Henry_W

    Henry_W Stunt Coordinator

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    Right on Bill - thanks for getting a simple solution to test the reciever first and placement second.

    Gosh - it makes way too much sense and is so darn simple that it hardly seems worthy, considering how we like to complicate our hobby...
     
  10. JohnnyG

    JohnnyG Screenwriter

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    Don't forget about the 'boundary effect' - the interaction of the speaker and the TV screen. If the speaker is on top of the TV, move it as far forward as possible to minimize this.
     
  11. RickBlacker

    RickBlacker Stunt Coordinator

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    So I finally got around to swapping the LF and the center connections. It IS the receiver. That same sound that was in the center speaker was coming from the LF once I swapped them, and the center took on the sound that the LF had.

    BTW, there is no TV in this room. My theater is in a room with a projector. [​IMG]

    H/K must must do this for dialog clarity or something.
     
  12. Jim_P

    Jim_P Stunt Coordinator

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    Rick

    I'm not sure if my Yamaha works the same way as your KH receiver, but it's worth a mention.

    The bass/treble control on the Yammy applies only to the front mains.

    There is also a graphic equalizer in one of the Yammy menus to sonic ally adjust the center channel to help sound match the center to the front mains.

    The interaction of these adjustments can very well cause identical speakers to sound different. If you have these adjustments, you may find that with some adjustment, you can match the sound.

    By the way, given the location of your speakers, you might want to do the clap test. I'd guess you getting an echo from those sidewalls. If you do, you would need to do something to kill that echo.
     
  13. Philip Hamm

    Philip Hamm Lead Actor

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    I would recommend tryint a test tone from something like a THX Optimode disc or a Video Essentials. If that sounds different I'd bring it up with H/K. I also have identical speakers up front, and while mine do not sound identical for test tones due to placment issues, they are very close.
     
  14. RickBlacker

    RickBlacker Stunt Coordinator

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    Jim, thanks I will look to see if my receiver has that functionality. I don't recall seeing it, but then I have never looked for it either.

    As far as echo, there is some to be sure. I have done lots of construction in my room which has reduced some of it, but right now the walls are bare with only drywall and paint. I am currently waiting the arrival of my book "Master Handbook of Acoustics". I am hoping it will give some good insight on how someone figures out how to determine areas in your room that would benifit from accoustic treatments.


    Philip, I have used the AVIA disk, off the top of my head it seemed as though I had the same issue with that DVD as well. (Prior to swapping cables). I will definilty try this again using that DVD to make sure.
     

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