Closed Thread
Page 1 of 2 1 2 LastLast
Results 1 to 15 of 19

Reload Thread: 9887 time correction confusion...

  1. #1
    groggy23's Avatar
    groggy23 is offline Senior VIP Member



    Join Date
    Jan 2007
    Location
    north VA
    Posts
    258
    Post Thanks / Like
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quoted
    0 Post(s)

    9887 time correction confusion...

    So I was reading the manual for the CDA-9887 specifically about time correction. I understand the concept but having trouble figuring out what exactly to calculate. I understand that you can adjust each individual channel. I have a current 3-way setup, front stage, no rears. Following Example 1 in the manual for front left seat. You take the distance between the listener and the closest/farthest speaker. Take farthest - closest = difference and calculate that into the time correction formula. Take that value and input that as the front left channel. Here is where my questions come in. Do I need to input a time correction value for each channel including subwoofer? If so, how do I do the calculate for each channel? For example for the front right that is my farthest already, so I would come up with a negative value to input for the time correction calculation? *scratches head*



    2004 Nissan Altima - Kenwood x-889 - DLS UR36i - eD 11Ov.2 - Arc Audio 4050xxk - iPod video
    Refs: hc3_cuz, dumple, LS-Coupe, bikinpunk, Bloodstalker999(x2), mschief02 on ebay




  2. #2
    bikinpunk's Avatar
    bikinpunk is offline G-g-g-g-g-unity!



    Join Date
    May 2006
    Location
    Alabama
    Posts
    3,224
    Post Thanks / Like
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quoted
    2 Post(s)

    Re: 9887 time correction confusion...

    #1. measure distance of all speakers.

    #2. Pick the furthest speaker. This will be your reference point.

    #3. Take the difference of each speaker from the furthest speaker.


    The furthest speaker (usually subwoofer) will be 0.00ms on the t/a, so basically you do no time correction for the furthest speaker. The closest speaker to you should have the most t/a since that's the largest difference.



    This is based on temperature since speed of sound is based on temperature, fyi. But, just assume some temperature for the sake of measurements.

    For example, the subwoofer is 66 inches and is the furthest speaker. The following is from an excel sheet I made. 2nd number is distance in inches, and 3rd number is time correction in milliseconds (ms).
    Subwoofer: 66 0
    Drivers Tweeter: 35 2.295628013
    Passengers Tweeter: 49 1.258892782
    Drivers Midrange: 37.5 2.110496722
    Passengers Midrange: 51 1.110787748
    Drivers Midbass: 41.25 1.832799785
    Passenger's Midbass: 55 0.814577682


    So, you see that the driver's side tweeter (which is the closest speaker to you) has the most t/a @ 2.29ms. The subwoofer has 0 t/a.


    One thing to keep in mind is reflection. If you have a speaker firing at the windshield you'll want to add some extra distance to account for that the best you can. Also, the excel sheet I use is just to give you an idea of where to start. You should play with the t/a a bit and listen to what you think sounds the best.

    Also, I actually added about 8ms to every t/a value I calculated so that the sub has plenty of time to get "up front" and doesn't sound like it's coming from behind as much.







    If you want a copy of the excel file I'll be happy to e-mail you one.
    Last edited by bikinpunk; 01-03-2008 at 11:49 PM.



    2006 Civic LX Sedan
    Pioneer P9. Audison BitOne. JL Audio HD. Scanspeak. Acoustic Elegance.

    DIYma Refs:
    http://www.diymobileaudio.com/forum/itrader.php?u=1891

    Caraudio.com refs:
    Groggy23, Radridd, bdubs767, 6spdcoupe, Cahm Rohn, Soydeedo, Lil_KB

    E-bay Feedback: bikinpunk

  3. #3
    groggy23's Avatar
    groggy23 is offline Senior VIP Member

    Threadstarter


    Join Date
    Jan 2007
    Location
    north VA
    Posts
    258
    Post Thanks / Like
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quoted
    0 Post(s)

    Re: 9887 time correction confusion...

    Thanks a bunch bikinipunk, that really cleared things up. So on step #3 wouldn't the farthest speaker always be the subwoofer?



    2004 Nissan Altima - Kenwood x-889 - DLS UR36i - eD 11Ov.2 - Arc Audio 4050xxk - iPod video
    Refs: hc3_cuz, dumple, LS-Coupe, bikinpunk, Bloodstalker999(x2), mschief02 on ebay

  4. #4
    bikinpunk's Avatar
    bikinpunk is offline G-g-g-g-g-unity!



    Join Date
    May 2006
    Location
    Alabama
    Posts
    3,224
    Post Thanks / Like
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quoted
    2 Post(s)

    Re: 9887 time correction confusion...

    Quote Originally Posted by groggy23 View Post
    Thanks a bunch bikinipunk, that really cleared things up. So on step #3 wouldn't the farthest speaker always be the subwoofer?
    More than likely, but not necessarily.

    I suppose you could say that if you have the sub under you or in your center console as I've seen, then it's closer than anything on the passenger's side.



    2006 Civic LX Sedan
    Pioneer P9. Audison BitOne. JL Audio HD. Scanspeak. Acoustic Elegance.

    DIYma Refs:
    http://www.diymobileaudio.com/forum/itrader.php?u=1891

    Caraudio.com refs:
    Groggy23, Radridd, bdubs767, 6spdcoupe, Cahm Rohn, Soydeedo, Lil_KB

    E-bay Feedback: bikinpunk

  5. #5
    whitemax's Avatar
    whitemax is offline CarAudio.com Elite



    Join Date
    Dec 2006
    Location
    San Diego
    Posts
    700
    Post Thanks / Like
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quoted
    55 Post(s)

    Re: 9887 time correction confusion...

    Each click of the dial (increment) is the same as a 1ms....




    2010 Nissan Maxima SV Premium with OEM DVD/Navigation HU
    AudioControl: DQ-61, 6XS
    Scan-Speak: Illuminator R3004/6020-00
    Audison: Voce AV 3.0
    Scan-Speak: Revelator 18W/4531G-00
    Audiomobile: MASS 2012 S24
    Boston Acoustics: GT-475, GT-2200

  6. #6
    groggy23's Avatar
    groggy23 is offline Senior VIP Member

    Threadstarter


    Join Date
    Jan 2007
    Location
    north VA
    Posts
    258
    Post Thanks / Like
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quoted
    0 Post(s)

    Re: 9887 time correction confusion...

    Thanks guys, got things cleared up



    2004 Nissan Altima - Kenwood x-889 - DLS UR36i - eD 11Ov.2 - Arc Audio 4050xxk - iPod video
    Refs: hc3_cuz, dumple, LS-Coupe, bikinpunk, Bloodstalker999(x2), mschief02 on ebay

  7. #7
    grampi's Avatar
    grampi is offline CarAudio.com Elite



    Join Date
    Aug 2002
    Location
    Cheyenne
    Posts
    723
    Post Thanks / Like
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quoted
    0 Post(s)

    Re: 9887 time correction confusion...

    I found the easiest way to do it is to use the difference between the two front speakers and dial that time correction into your front left side, then just dial in the time correction for the sub while you're listening to it until it sounds like it's coming from the front.




  8. #8
    groggy23's Avatar
    groggy23 is offline Senior VIP Member

    Threadstarter


    Join Date
    Jan 2007
    Location
    north VA
    Posts
    258
    Post Thanks / Like
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quoted
    0 Post(s)

    Re: 9887 time correction confusion...

    Thanks for the tip grampi.



    2004 Nissan Altima - Kenwood x-889 - DLS UR36i - eD 11Ov.2 - Arc Audio 4050xxk - iPod video
    Refs: hc3_cuz, dumple, LS-Coupe, bikinpunk, Bloodstalker999(x2), mschief02 on ebay

  9. #9
    groggy23's Avatar
    groggy23 is offline Senior VIP Member

    Threadstarter


    Join Date
    Jan 2007
    Location
    north VA
    Posts
    258
    Post Thanks / Like
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quoted
    0 Post(s)

    Re: 9887 time correction confusion...

    nevermind.
    Last edited by groggy23; 01-06-2008 at 01:01 AM.



    2004 Nissan Altima - Kenwood x-889 - DLS UR36i - eD 11Ov.2 - Arc Audio 4050xxk - iPod video
    Refs: hc3_cuz, dumple, LS-Coupe, bikinpunk, Bloodstalker999(x2), mschief02 on ebay

  10. #10
    groggy23's Avatar
    groggy23 is offline Senior VIP Member

    Threadstarter


    Join Date
    Jan 2007
    Location
    north VA
    Posts
    258
    Post Thanks / Like
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quoted
    0 Post(s)

    Re: 9887 time correction confusion...

    Ok, getting a little confused now. On the 9887 unit, I see you can input #'s in distance cm or inches for each channel. So I'll just take the distance for each speaker to my head and input that?



    2004 Nissan Altima - Kenwood x-889 - DLS UR36i - eD 11Ov.2 - Arc Audio 4050xxk - iPod video
    Refs: hc3_cuz, dumple, LS-Coupe, bikinpunk, Bloodstalker999(x2), mschief02 on ebay

  11. #11
    bikinpunk's Avatar
    bikinpunk is offline G-g-g-g-g-unity!



    Join Date
    May 2006
    Location
    Alabama
    Posts
    3,224
    Post Thanks / Like
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quoted
    2 Post(s)

    Re: 9887 time correction confusion...

    Yea. I was looking over the 9887 one day after I posted my response. A friend wanted it and I was doing the research for him and I noticed that they don't do t/a in ms like the other h/u's do, and rather you just input the distance. That makes things much simpler.



    2006 Civic LX Sedan
    Pioneer P9. Audison BitOne. JL Audio HD. Scanspeak. Acoustic Elegance.

    DIYma Refs:
    http://www.diymobileaudio.com/forum/itrader.php?u=1891

    Caraudio.com refs:
    Groggy23, Radridd, bdubs767, 6spdcoupe, Cahm Rohn, Soydeedo, Lil_KB

    E-bay Feedback: bikinpunk

  12. #12
    groggy23's Avatar
    groggy23 is offline Senior VIP Member

    Threadstarter


    Join Date
    Jan 2007
    Location
    north VA
    Posts
    258
    Post Thanks / Like
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quoted
    0 Post(s)

    Re: 9887 time correction confusion...

    Alright, that's what I figured. But here's the kicker. I think it wants you to input "L" which is the following equation, not the actual distance from listener to each speaker.
    L = (distance of farthest speaker) - (distance of speaker you want to adjust)
    Then you input L into the channels you want to adjust.

    From how I understand is you adjust only the ones close to you and by playing around that's what sounded right to me. So I ended up adjusting my drivers tweet/mid/midbass, and leaving the rest at 0.

    Because I tried inputing the numbers just by the distances alone and everything sounded way out of alignment. I got around 20cm for my tweet/mid and



    2004 Nissan Altima - Kenwood x-889 - DLS UR36i - eD 11Ov.2 - Arc Audio 4050xxk - iPod video
    Refs: hc3_cuz, dumple, LS-Coupe, bikinpunk, Bloodstalker999(x2), mschief02 on ebay

  13. #13
    bikinpunk's Avatar
    bikinpunk is offline G-g-g-g-g-unity!



    Join Date
    May 2006
    Location
    Alabama
    Posts
    3,224
    Post Thanks / Like
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quoted
    2 Post(s)

    Re: 9887 time correction confusion...

    You will adjust EVERYTHING except the furthermost speaker.

    Like I explained above, you will have a delta x (difference of distance) for every point based on the furthest driver as the reference driver.



    2006 Civic LX Sedan
    Pioneer P9. Audison BitOne. JL Audio HD. Scanspeak. Acoustic Elegance.

    DIYma Refs:
    http://www.diymobileaudio.com/forum/itrader.php?u=1891

    Caraudio.com refs:
    Groggy23, Radridd, bdubs767, 6spdcoupe, Cahm Rohn, Soydeedo, Lil_KB

    E-bay Feedback: bikinpunk

  14. #14
    groggy23's Avatar
    groggy23 is offline Senior VIP Member

    Threadstarter


    Join Date
    Jan 2007
    Location
    north VA
    Posts
    258
    Post Thanks / Like
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quoted
    0 Post(s)

    Re: 9887 time correction confusion...

    Ah I see, so I assume the only one I won't adjust is the subwoofer. Also, The distance I input for each driver is the distance from me to that speaker?



    2004 Nissan Altima - Kenwood x-889 - DLS UR36i - eD 11Ov.2 - Arc Audio 4050xxk - iPod video
    Refs: hc3_cuz, dumple, LS-Coupe, bikinpunk, Bloodstalker999(x2), mschief02 on ebay

  15. #15
    bikinpunk's Avatar
    bikinpunk is offline G-g-g-g-g-unity!



    Join Date
    May 2006
    Location
    Alabama
    Posts
    3,224
    Post Thanks / Like
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quoted
    2 Post(s)

    Re: 9887 time correction confusion...

    Quote Originally Posted by groggy23 View Post
    Also, The distance I input for each driver is the distance from me to that speaker?
    Unless the manual states otherwise, I would assume this is true.



    2006 Civic LX Sedan
    Pioneer P9. Audison BitOne. JL Audio HD. Scanspeak. Acoustic Elegance.

    DIYma Refs:
    http://www.diymobileaudio.com/forum/itrader.php?u=1891

    Caraudio.com refs:
    Groggy23, Radridd, bdubs767, 6spdcoupe, Cahm Rohn, Soydeedo, Lil_KB

    E-bay Feedback: bikinpunk

Closed Thread
Page 1 of 2 1 2 LastLast

User Tag List

Posting Permissions

  • You may not post new threads
  • You may post replies
  • You may post attachments
  • You may edit your posts
1e2 Forum