Anyone Familiar With the Avia 6 Channel Pan?

Discussion in 'Archived Threads 2001-2004' started by Jason Wolters, Jan 3, 2002.

  1. Jason Wolters

    Jason Wolters Stunt Coordinator

    Joined:
    Dec 18, 2001
    Messages:
    227
    Likes Received:
    0
    Trophy Points:
    0
    During the 6 channel span test on the Avia DVD, I have a pretty significant drop when it goes to the LFE. I don't have LFE adjustment with my Kenwood VR 507 receiver. What can I do to help this?
     
  2. BruceD

    BruceD Screenwriter

    Joined:
    Apr 12, 1999
    Messages:
    1,220
    Likes Received:
    0
    Trophy Points:
    0
    What speakers do you have hooked up to the Kenwood and how are they defined?

    I don't have the AVIA disk, so what does it tell you to expect?

    I would generally expect you need to turn up the sub's volume control to match the SPL of the other speakers in the pan.

    BruceD
     
  3. Jason Wolters

    Jason Wolters Stunt Coordinator

    Joined:
    Dec 18, 2001
    Messages:
    227
    Likes Received:
    0
    Trophy Points:
    0
    Bruce,

    You can match the sub to the other channels during the sub matching tests. I can do this with no problem. This, however does not contain LFE. During the 6 channel pan test it does have LFE as one of the channels. It says to make sure they sound roughly the same. It doesn't say to use the SPL meter for this test, just your ears. My ears detect a significant drop when it switches to the LFE. I have all Pioneer Speakers. Mains are floor speakers with 12" woofers. All speakers are set to small. I have a Paradigm PDR 10 sub.
     
  4. ChrisSk

    ChrisSk Extra

    Joined:
    Dec 19, 2001
    Messages:
    17
    Likes Received:
    0
    Trophy Points:
    0
    Check again using your SPL meter, the ear is less sensitive to lower frequencies and bass will sound quieter than it really is.
     
  5. BruceD

    BruceD Screenwriter

    Joined:
    Apr 12, 1999
    Messages:
    1,220
    Likes Received:
    0
    Trophy Points:
    0
    Jason,

    What is the Kenwood's crossover frequency?

    I assume you have the sub's own crossover turned off or set to it's highest position (120Hz?).

    You said there are frequency differences for the speaker pan vs. the LFE pan? Do the actual AVIA tests themselves produce different frequency ranges? Like the speaker pan is just pinknoise and the LFE pan is low frequency only?

    1) You may be experiencing a room-mode null, a valley or decline in SPL at a specific bass frequency because of sub position and room size (listening position matters also).

    You might try moving the sub (or listening position) for a better response from the LFE pan.

    BruceD
     
  6. Jason Wolters

    Jason Wolters Stunt Coordinator

    Joined:
    Dec 18, 2001
    Messages:
    227
    Likes Received:
    0
    Trophy Points:
    0
     
  7. BruceD

    BruceD Screenwriter

    Joined:
    Apr 12, 1999
    Messages:
    1,220
    Likes Received:
    0
    Trophy Points:
    0
    Jason,
    Well, I can't seem to help you and really don't understand why you're matching your sub SPL to the center channel.
    Anyway, since I can't seem to understand what you are trying to do with AVIA, I suggest you do an author search of these threads for all of the posts by Guy Kuo who actually produced the AVIA test disk.
    I remember him giving very detailed instructions about how to use it to calibrate your speaker systems and specifically your sub.
    Just as an aside, not all DVDs have LFE content, and since you have all your speakers to small all re-directed bass plus LFE is sent to your sub. Your particular sub may not be able to drive enough air in your large size room for all that bass (redirected + LFE) at high SPLs for all those low frequencies.
    BruceD
     
  8. Jason Wolters

    Jason Wolters Stunt Coordinator

    Joined:
    Dec 18, 2001
    Messages:
    227
    Likes Received:
    0
    Trophy Points:
    0
     
  9. Jimmy P

    Jimmy P Stunt Coordinator

    Joined:
    Jul 1, 2001
    Messages:
    82
    Likes Received:
    0
    Trophy Points:
    0
    Jason,

    What is the sub level in relation to the mains? do one of the mains match the sub level? and on the other main the sub level is low? I know you said the sub is set in relation to the center channel,but if the other channels give the readings ive described,that would mean the sub is out of phase with the mains and that is what is partially to blame for the low lfe pan.
     
  10. Jason Wolters

    Jason Wolters Stunt Coordinator

    Joined:
    Dec 18, 2001
    Messages:
    227
    Likes Received:
    0
    Trophy Points:
    0
     
  11. Scott-C

    Scott-C Supporting Actor

    Joined:
    Jul 23, 2001
    Messages:
    863
    Likes Received:
    0
    Trophy Points:
    0
    For what it's worth, I've had a similar experience to Jason. I have a Yamaha DSP-A3090 integrated amp, calibrated using its internal test tones. Tonight I ran the Avia 6-channel sweep and also noticed that my LFE SPL was off significantly from the other channels - about 6 to 8 Db lower! Prior to running the sweep, I calibrated the sub to the left front speaker and while I didn't expect LFE to be exactly matched during the sweep, I was surprised it dropped off so much. Confusing...
     
  12. BruceD

    BruceD Screenwriter

    Joined:
    Apr 12, 1999
    Messages:
    1,220
    Likes Received:
    0
    Trophy Points:
    0
    Jason and Scott,

    You might have some sub vs. main phase problems when getting a lower reading for the LFE test.

    Here is what Guy said about getting the phase right, the speaker delay (distance) right, and the best crossover frequency, note the mention of peaky bass in some rooms.

    Have you both attempted this? If your sub has no phase switch at all, you could switch the speaker leads on the other 5 speakers to alter the phase between them and the sub.

    quote from a post by Guy on another board:

    --------------------------------------------------------

    "The low frequency phase tests in AVIA have acoustic energy throughout the usual bandpass region. If the subwoofer is out of phase with the speaker channel being tested, partial cancellation of some frequencies will occur and the sound will tend to deemphasize some frequencies in the test tone. Set phase of the subwoofer to make the sound have the widest audible range of frequencies. It is impossible to do this alone. An assistant is required to flip the phase control while you listen for this to work correctly. It simply takes too long to walk up to your sub, flip the phase, and return to your seat. Instant A/B comparison is needed.

    Lacking an assistant, you can use your SPL meter by positioning it at your normal head position. Note the SPL reading as the test tone is played in each phase. Select the phase with the higher reading as that is the one with the least overall cancellation of sound between the two speakers (main and subwoofer). If your sub has a variable phase control rather than a 180 degree switch, slowly adjust the phase to maximize the SPL reading. At that point the sub and main speaker are at best phase coherence.

    If you note little or no change as phase is adjusted, make sure that the delay or distance settiings for all your speakers are correct. If they are grossly wrong, the system may be delaying one signal so far that it will never come into phase.

    The choice of crossover frequency is often fixed at 80 Hz. Some pre/pro's or subs have an adjustable crossover. The warble test tones in AVIA help you find a good crossover point. The tests waver up and down in frequency but not in amplitude. They sweep through the crossover range and well below. The warble effect allows the signal to act as its own comparison level. Bass response is often spikey in a room with small changes in frequency making a large change in response. The warble lets you detect unevenness more easily. If you hear a big appearance/disappearance of the test tone, then the warble is sweeping through a frequency range with a large inequality in response. Play the warble tone and adjust the crossover freq to make overall response as flat as possible during the first (higher freq) portion of the test. That should be the portion which is affected by the crossover.

    It may be necessary to redo phase after adjusting crossover frequency. The two controls will interact. Once crossover freq and phase are adjusted, go back and redo the subwoofer level adjustments. They will also be affected."

    -----------------------------------------------------------

    BruceD
     
  13. Jason Wolters

    Jason Wolters Stunt Coordinator

    Joined:
    Dec 18, 2001
    Messages:
    227
    Likes Received:
    0
    Trophy Points:
    0
    I think there is something else going on here. I hooked up my old sub that did have a phase switch. I tried it both ways and got the same results. On the 6 channel pan the LFE drops regardless.

    Is there anyone out there, that has performed the 6 channel pan and NOT heard a drop on the LFE?
     
  14. Scott-C

    Scott-C Supporting Actor

    Joined:
    Jul 23, 2001
    Messages:
    863
    Likes Received:
    0
    Trophy Points:
    0
    BruceD,

    Thanks for this info. I'm going to adjust the phase of my sub tomorrow and see if this corrects some/all of the problem. I'll report my findings on this thread. My sub has an adjustable phase dial, so I'll try all the settings.
     
  15. Jon D

    Jon D Stunt Coordinator

    Joined:
    Sep 29, 2000
    Messages:
    166
    Likes Received:
    0
    Trophy Points:
    0
    I'm chiming in with the same situation. I suppose you could calibrate your sub output so the LFE in the 6 channel pan reads the same SPL as the mains using the level sets in the 'main speaker setup' section. The problem is then the bass from the mains/center/surrounds will be 6 Db too loud then. Is it possible that the levels on the Avia disc might be off?
     
  16. Jason Wolters

    Jason Wolters Stunt Coordinator

    Joined:
    Dec 18, 2001
    Messages:
    227
    Likes Received:
    0
    Trophy Points:
    0
    That is my opinion. I can't see what else it could be, since I have eliminated phase as a possible cause. I have also tried changing placement. I wish others would do this test so I could find out if it is just a few of us or everyone.???
     
  17. BruceD

    BruceD Screenwriter

    Joined:
    Apr 12, 1999
    Messages:
    1,220
    Likes Received:
    0
    Trophy Points:
    0
    Jason,
    I remember asking you to do a search for this info:
    You didn't, so here is your answer from Guy's previous post on this forum on Sep 6, 2001, as you can see the level on the LFE pan is -10dB down:
    quote:
    ----------------------------------------------------------
    No. The only compensation is for the discrete LFE in the 6 channel pan. That is 10 dB down electrically.
    It would have been undesirable to alter the tones to specfically compensate for a single model of SPL meter. It would have made a mess for any other equipment because that poor sould would have to undo the compensation built into a signal for the RS meter and then applying the correction for the meter being used. Far better to keep it standard and only expose the users to a single layer of compensations.
    The signals are kept at electrical equal energy and you should compensate for your particular SPL meter. That means on the RS meter making the SPL reading equal 85 dB to match the 85 dB on the main tests yields a sub which is actually a few dB louder than neutral. Since so many of us HT fans like a lot of LF effects and don't listen at full reference volume, this yields an often more pleasing effect than a fully flat system.
    ------------------
    Guy Kuo
    www.ovationsw.com
    Ovation Software, the Home of AVIA DVD
    ----------------------------------------------------------
    BruceD
     
  18. Jason Wolters

    Jason Wolters Stunt Coordinator

    Joined:
    Dec 18, 2001
    Messages:
    227
    Likes Received:
    0
    Trophy Points:
    0
    Bruce,
    With all do respect, I did do what you told me to do. Assuming that I hadn't followed your advice based on the fact that I still don't have an answer is wrong.
    First, let me say that I am a newbie. I apologize if I am not picking this up at a rate which is satisfactory to you. [​IMG]
    I have read countless posts by Guy Kuo regarding bass management. I had read all of the threads you gave me countless times before you even gave them to me.
    So in the interest of solving the problem and not concentrating on how slow I am at figuring out the solution, perhaps you would like to put it into newbie terms that I can understand.
    Here is the problem again....(just lay the answer out for me as cleary as you can[​IMG] )
    [​IMG] On the Avia DVD, during the 6 channel pan mode, the menu tells you to listen to the tone as it circultates through all channels, including LFE. It says that if you HEAR (not measure) a difference between LFE and the other channels, you should try and adjust the LFE level on your receiver. And as I said before, I STILL don't have this feature. I have tried adjusting phase with no difference. I have tried placement changes with no difference. I have checked and rechecked speaker distances. I am sure you have laid the answer out there for me, but I still don't see it. Please tell me in simple terms, why the LFE SOUNDS lower on the 6 channel pan? Why does the menu tell me it should sound the same?
    [​IMG]
     
  19. BruceD

    BruceD Screenwriter

    Joined:
    Apr 12, 1999
    Messages:
    1,220
    Likes Received:
    0
    Trophy Points:
    0
    Does this answer your question?

    quote:

    ----------------------------------------------------------

    No. The only compensation is for the discrete LFE in the 6 channel pan. That is 10 dB down electrically.

    . . . . . . . . . .

    ----------------------------------------------------------

    A signal that is intentionaly 10dB lower electrically will produce a lower SPL output on your SPL meter.

    BruceD
     
  20. Jason Wolters

    Jason Wolters Stunt Coordinator

    Joined:
    Dec 18, 2001
    Messages:
    227
    Likes Received:
    0
    Trophy Points:
    0
     

Share This Page