Page 2 of 13 FirstFirst 123412 ... LastLast
Results 16 to 30 of 195

Thread: SR pros on this forum

  1. #16
    Senior Moment Member Oldmics's Avatar
    Join Date
    Apr 2003
    Location
    Between Venus and Mars
    Posts
    872
    Can you run pink noise thru a channel on the console.Make sure that the channel supplying the pink noise has the E.Q. in bypass mode.


    Bypass all equalisers for the mains (foh eq,dbx driverack,etc) and then take a reading with your RTA and post a picture of it here.

    I"m thinking the horns are not functioning correctly.

    Oldmics

  2. #17
    Senior Member chad's Avatar
    Join Date
    Oct 2005
    Location
    Spokane WA
    Posts
    111
    I'd have to second the notion that something is phased back asswards. Personaly, I'd probably put a guy in the air and a guy at the console and:

    1) play recorded music through each enclosure individually to ensure that each driver in each cabinet is functioning

    2) do the 9v battery trick to ensure that each cab is phased properly

    Good luck and keep us posted on your findings....

  3. #18
    pelly3s
    Guest
    galaxy audio sells a phase checker which isnt too expensive. most problems tend to be phase issues. in theory the low end drivers should be seperated no more than 1/5 the wavelength of the frequency the box is tuned for, but most of the time that is impossible so ignore i said that. check phase on everything and see how that works for you first.

  4. #19
    Senior Member JuniorJBL's Avatar
    Join Date
    Feb 2004
    Location
    Utah
    Posts
    1,723

    OK!

    Phase has been checked!
    HF was out of phase at the amp. (amps are in mono running both center speakers 2amps per cluster. LF amps are Crown CTs 1200's and HF's are CTs 600's.) so that means that both HF's from the center were out of phase from the rest of the system.
    1 LF is out of phase but I reversed it at the connection outside the box.
    Everything is in phase now.

    BTW I was wrong about what speaker it was. They are Venue 3115's.
    http://www.jblpro.com/pub/obsolete/venue/vs3115.pdf

    Phase problem is still evedent as you move around. Not as bad as before but still bad. Some areas sound fine and others sound very bad.
    The side speakers sound way better then the centers. Sorry I did not get a pic.

    The 3115's must use some kind of crossover for the LF. This is the design. They are running in the bi-amp mode.

    From the looks of things, it looks as though I am going to have to move them.
    I did run the boxes w/o the driverack and no difference.

    JBL recomended crossover points
    http://www.jblpro.com/tunings/venue.pdf

    BTW all drivers are working!

    Thanks again for all your help.
    SHane

  5. #20
    Senior Member JuniorJBL's Avatar
    Join Date
    Feb 2004
    Location
    Utah
    Posts
    1,723

    This is what we did!

    Quote Originally Posted by chad
    I'd have to second the notion that something is phased back asswards. Personaly, I'd probably put a guy in the air and a guy at the console and:

    1) play recorded music through each enclosure individually to ensure that each driver in each cabinet is functioning

    2) do the 9v battery trick to ensure that each cab is phased properly

    Good luck and keep us posted on your findings....
    We did just that! Thanks Chad

  6. #21
    RIP 2011 Zilch's Avatar
    Join Date
    Jun 2004
    Location
    Berkeley, CA
    Posts
    9,963
    http://www.jblproservice.com/pdf/Ven.../VS3115-WH.pdf

    Shows the network.

    No filter on the LF in any mode.

    Mid filter is bypassed in the tri-amp mode.

    Mid/high driver combo is rotatable for the ones that are horizontal....

  7. #22
    Senior Seņor boputnam's Avatar
    Join Date
    Apr 2003
    Location
    northern california
    Posts
    6,142
    Quote Originally Posted by JuniorJBL
    Phase problem is still evident as you move around. Not as bad as before but still bad. Some areas sound fine and others sound very bad.
    The side speakers sound way better then the centers.
    Wow, Shane - cool.

    I always revert to checking the signal path and wiring before I blame the components - but to do that, one must get back to first principals. Well done. Nice job. BTW, where did you find the cross-wiring to be?

    I wonder if what you are now describing is actually "lobing" and not a phase problem, per se. Different solutions...

    Do you need the centers, really? Maybe with the corrected wiring, you've got plenty of SPL and good enough "spray" with just the sides? Dunno... I'm not understanding why they would sound any different than the sides. You checked all the wiring up in the loft, too? Maybe standing the Centers on their heads, might help? Maybe the sides are getting a beneficial MF/HF reflection off the proscenium walls - the centers would not be getting that, and are not spraying as effectively to the floor. Again, dunno...

    And, as Zilch notes, the passive xover is between the MF and HF, at 1.6kHz. I don't know that you need to go tri-amped, but the dbx could handle it (but you need more amps...).
    bo

    "Indeed, not!!"

  8. #23
    Senior Member JuniorJBL's Avatar
    Join Date
    Feb 2004
    Location
    Utah
    Posts
    1,723

    Crossover points

    I have set the crossover points and slopes as per the JBL manual.
    I am sure that standing the speakers vertical would help but if I am going to do that I may as well move them out to the edges 5' and get the "stereo" effect.
    Not that my signal would be stereo (but it can be) and yes the only thing about Tri-amping is 2 more amps. So I thing bi-amp is our better approach.
    I am not sure when we will do the switch but it should be soon. I will remember my camera next time and get lots of pics.

    Any other suggestions are welcome.

    Shane

  9. #24
    Senior Member JuniorJBL's Avatar
    Join Date
    Feb 2004
    Location
    Utah
    Posts
    1,723

    Thanks Zilch!!

    Quote Originally Posted by Zilch
    http://www.jblproservice.com/pdf/Ven.../VS3115-WH.pdf

    Shows the network.

    No filter on the LF in any mode.

    Mid filter is bypassed in the tri-amp mode.

    Mid/high driver combo is rotatable for the ones that are horizontal....
    I was looking for that info

  10. #25
    Senior Member chad's Avatar
    Join Date
    Oct 2005
    Location
    Spokane WA
    Posts
    111
    Quote Originally Posted by JuniorJBL
    ....I may as well move them out to the edges 5' and get the "stereo" effect.....I will remember my camera next time and get lots of pics.

    Any other suggestions are welcome.

    Shane
    Moving the center cluster out to the sides was going to be my next suggestion.

    Oh, and yes we'd like to see pics of the rig.

  11. #26
    Senior Member edgewound's Avatar
    Join Date
    Jun 2005
    Location
    Southern California
    Posts
    2,776
    Hi Shane....your patience is admirable...nice detective work.

    Is it really necessary for two speakers in the center? I'd flip the speakers so the horn is on the bottom to minimize reflections off the ceiling that can cause phase and lobing problems. One center speaker will simplify your solution so two close units don't fight with each other. If you must keep the two centers, I'd splay them so the horns' coverages don't overlap and cause lobing problems, still keeping all speakers in the array oriented with the horns on the bottom.
    Edgewound...JBL Pro Authorized...since 1988
    Upland Loudspeaker Service, Upland, CA

  12. #27
    Senior Member JuniorJBL's Avatar
    Join Date
    Feb 2004
    Location
    Utah
    Posts
    1,723

    Placement

    Quote Originally Posted by edgewound
    Hi Shane....your patience is admirable...nice detective work.

    Is it really necessary for two speakers in the center? I'd flip the speakers so the horn is on the bottom to minimize reflections off the ceiling that can cause phase and lobing problems. One center speaker will simplify your solution so two close units don't fight with each other. If you must keep the two centers, I'd splay them so the horns' coverages don't overlap and cause lobing problems, still keeping all speakers in the array oriented with the horns on the bottom.
    I am now going for placement of left and right with the way the room is designed this should be a semi-standard FOH setup. But you are right I am not aiming to keep it center. When they are moved I will end up with a left side and a left front same with the right.

    So kinda like they do for large format concerts.
    Example: Vertec's will create a curve when you fly them. It will be sorta like that on a MUCH MUCH smaller scale.

  13. #28
    Senior Member edgewound's Avatar
    Join Date
    Jun 2005
    Location
    Southern California
    Posts
    2,776
    Quote Originally Posted by JuniorJBL
    I am now going for placement of left and right with the way the room is designed this should be a semi-standard FOH setup. But you are right I am not aiming to keep it center. When they are moved I will end up with a left side and a left front same with the right.

    So kinda like they do for large format concerts.
    Example: Vertec's will create a curve when you fly them. It will be sorta like that on a MUCH MUCH smaller scale.
    Sounds like you've got the scenario under control. Your church is fortunate to have a guy like you putting in so much effort and care to improve the system. Lots of people just don't understand and under-appreciate the undertaking of arranging a good sound system.
    Edgewound...JBL Pro Authorized...since 1988
    Upland Loudspeaker Service, Upland, CA

  14. #29
    Tom Loizeaux
    Guest
    It's great to know that all your drivers and cabinets are in phase...however, sometimes switching phase on a peticular driver can "improve" the over-all sound. Crossovers rotate phase, depending on the slope, and, of course, distance from the listener can "create" phase problems...which sometimes can be reduced by switching or rotating phase or using some time delay on certain units.
    It can get complicated!

    Tom

  15. #30
    RIP 2011 Zilch's Avatar
    Join Date
    Jun 2004
    Location
    Berkeley, CA
    Posts
    9,963
    If the two center ones are playing mono and both aimed forward, they'll majorly interfere with each other.

    Consider the directivity spec. Horizontal coverage (-6dB) is 70 degrees.

    I'd keep the centers horizontal, woofers at center, rotate the mid/high horns into the normal vertical position, angle them out at 67.5° with respect to each other (total included angle), and then tilt them down 25° to 30°. The vertical coverage (-6dB) is 50°. There seems little point in bouncing half of that (500 Hz to 16 kHz) off the ceiling other than to compound the problem with spurious reflections....

    Alternatively, if you want the center narrower, keep the mid/high in the horizontal orientation, angle them out at 45° with respect to each other (included angle), and tilt down 35° to 40°.

    I'm not an SR pro, and I haven't studied the Sound Reinforcement manual (in the JBL Pro website tech library) , but I do know those specs mean quite a bit with respect to placement and intelligibility.

Thread Information

Users Browsing this Thread

There are currently 2 users browsing this thread. (0 members and 2 guests)

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •