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Spectrum Analyzer - SPL meters - Subs - Recvr -Signal Sources

Discussion in 'Archived Threads 2001-2004' started by tim_t, Jul 16, 2001.

  1. tim_t

    tim_t Auditioning

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    I am puzzler over how to tune for everything starting from the least tunable to the most tunable.
    What I'm working with:
    15" Definitive Sub
    Klipsch Forte mains and Klipsch surrounds
    Yamaha DSP-A1
    Technic A-10 DVD-Audio
    Sony ES CD-Player
    Yamaha 850 tunner
    RCA Laser disk Player
    ---------
    Portable computer with full duplex sound board w/mic running Dazyweb Labs signal generator and sprectrum analyzer software
    Radio Shack SPL meter
    This all started when I decided that my sub didn't have enough punch during explosions while watching movies. Trying several simple things such as retunning with Video Essential resulted in frustrations and my research began. Thirteen hours into this I think I've settled on a plan of action and wanted to run it by you all to see if it makes sense.
    First, I turned off all effect processing,measurred and reset the cross-over between the sub woofer and the mains using the sprectrum analyzer. During this I noticed that if I turned the sub 90 degrees out of phase I had a straighter cross-over as far as the SPL was concerned, but there was still a bit of dip [ I have sprectragrams saved as pictures if anyone wants to see them]. In addition I am going to set the volumn level on the sub so it is as horizontal as possible across all the frequience, using my main's response as the base from which to work from. I am setting this first since music reproduction was just a smidge more important to me than movie Booms.
    Second, I will go into the Yamaha DSP-A1 and where you can set the LFE dbs for Dolby Surround change those setting to match what Video Essentials tells me they should be and if that doesn't work..!!! I'm not sure where to go.
    Third, I will go into the Yamaha DSP-A1 and where you can set the LFE dbs for DTS, I am going to change those to... probably what ever my ear tells me. Don't really know yet.
    Fourth, the DVD-Audio/DVD player also its owns LFE setting that I'll try and set with Video Essentials, although I'm not quite sure if thei chnage will effect both DD and DTS.
    So what do you all think? Any suggestions.
    ------------------
     
  2. JerryHatchett

    JerryHatchett Stunt Coordinator

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    I don't have any suggestions but I do plan to follow your quest with interest. [​IMG]
    I'd love to hear more about the SA software that runs on your notebook. Got links?
    Thx and good luck...
    Jerry
     
  3. Timmy

    Timmy Stunt Coordinator

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    With all that nice test gear, remember that you are "tuning" for the specific area where the mic is sitting. 18inches forward or back from that spot may yield different results (especially in the 20 to 100hz region).
     
  4. tim_t

    tim_t Auditioning

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    I tried 10 or 12 various softwares packages looking for a spectrum analyzer that was decient, easy to use, and priced for the hobbiest or aoccassional user. I found some nice high priced stuff and mid priced stuff, but best deal all around seems to be the DazyWeb Labs software. The software was easy to use and failry easy to understand and Freeware. Apparently the developers hobby is writing software like this. Cool. My choice to use it is not becasue it is Freeware; I use it beacuse it actually is pretty good, and better than most. Dazyweb Labs website is:http://www.geocities.com/vrbalthezr/...oft/page3.html
    He has a link to another audio test equiptment site too that may be of some interest.
    ___________________
    You're right on the 20 to 100 Hz sounding different depending on where you are in the room. I've tried to get as close to my normal listening position as possible for all of the testing. Keeping everything exactly the same except for what I currently tweaking, like sub volumn on the sub.
     
  5. JerryHatchett

    JerryHatchett Stunt Coordinator

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    Thx for the link...
     
  6. Chris PC

    Chris PC Producer

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    Cool. Also thanks for the link.
    What about sub placement?
     
  7. BruceD

    BruceD Screenwriter

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    I can't give you specific advice on the Yamaha settings, but I can point everyone to some software I've been using for about 4 months called ETF5.
    It uses a more accurate MLS impulse response analysis system (no test disks needed).
    The website also has some really great training aids through the use of a demo room example. They go through all kinds of issues such as; sub crossovers, room modes, distance to each speaker, first reflections, etc. You should visit the site just for a better understanding of what all the graphs mean.
    www.etfacoustic.com
    I think cost is about $149, and you can use your RS SPL meter's RCA output jack as the line-in to the PC soundcard.
    [Edited last by BruceD on July 16, 2001 at 09:36 PM]
     
  8. tim_t

    tim_t Auditioning

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    I thought about sub placement. Decided to leave it for now between the two mains at the front of the room, it sounds good with music,looks good, the wifes happy with it, and the kids stay off of it for the most part. The sub gets down to 5 Hz and less but the SPL is low at those ranges. At 19 Hz its at it's peak SPL which it carries to around 63 Hz where it dips for some reason and climbs back up to continue on into where the mains pick up. The SPL at 21 through 23 Hz for example is seriously rattling ALL the springs in the double-hung cassment windows in our 2,300 sqr ft 3 story house. There are floor boards squeaking and nails coming up, through, and out of things they shouldn't be and house is only 9 years old, all of which could be caused by other things, but I suspect the sub is somewhat to blame as the neightbors with similar aged house don't seem to have these "features." All that said, there is/was still no immediate punch when something blew up. Definely nothing like the bass-head thread on DVDs with lots of bass described last September.
    Placement is a very good thought. Thanks. -tim
     
  9. tim_t

    tim_t Auditioning

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    Bruce,
    Thanks for thewww.etfacoustic.com web site. I've read about half of it or so and it has filled in some gaps and explained a few things and given me more possibilities to consider. It think I'll spend the next day or so digesting it before I make any more changes. Thanks -tim
     
  10. Stephen Dodds

    Stephen Dodds Second Unit

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    You're probably best off moving your sub into a corner for maximum excitation of room modes. Then use a parametric equalizer to flatten the response. The Behringer Feedback Destoryer is cheap and easyish to use. There is an FAQ at www.hometheatertalk.com.
    You can use your SA program to get the readings to adjust on the sub, or the RS meter.
    Then I would adjust your main speakers for best imaging, and cross them over via your receiver. Presumably it will do this at 80Hz.
    Then adjust for levels.
    This should give you the smoothest and deepest bass.
    The LFE crossovers in your DVD-A player only apply if you are using the analog outputs, which is probably not the easiest way to do things.
    Steve
    ------------------
    Steve's Toys
    [Edited last by Stephen Dodds on July 17, 2001 at 01:10 AM]
     
  11. tim_t

    tim_t Auditioning

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    Thanks Steve.
    I'm going through the Home Theature Talk section now. I found 138 hits so it may take awhile.
    -tim
     

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