First measurment, 10hz Extension!

Discussion in 'Archived Threads 2001-2004' started by Chris Tsutsui, Oct 11, 2002.

  1. Chris Tsutsui

    Chris Tsutsui Screenwriter

    Joined:
    Feb 1, 2002
    Messages:
    1,865
    Likes Received:
    0
    I'm blown away after my first measurement of my room I took today. I recorded a response that has 10hz still well in the graph's response. (Dual 214L tempests tuned to 15.4hz)
    Link to graph
    If that link doesn't work, go to my site and click on the thumbnail at the top. You can also DL the worksheet I used to graph the results and see a couple room pics at the bottom.
    The acoustic panels are finally up but no bass traps (as you'll see from the response graph). [​IMG]
    At least the response makes senses to "physics" and theory since I calculated the room modes (using the excel file) and the dips/peaks are as predicted.
    My room is 11-13.5' in length (due to closet), 8' high, and 10' wide. Not exactly ideal but I have plans for it [​IMG]
    The first dip near 63hz sounds related to the height resonance. The volume gets a severe drop towards the middle of the room and as the mic approaches the ceiling or floor the volume increases no matter where in the room.
    First peak near 83hz is the 2nd order 13.5' length resonance.
    100hz dip could be due to the 2nd order 11' length and width mode combined.
    The 140 and 160hz artifacts are likely due to 3rd order room modes.
    Keep in mind this is my first response recording with the 2 subs in a left/right corner fashion. The subwoofer crossovers are set to 40hz and the mains are set to small, phase is 180 deg on both subs to maximize SPL which could be a cause of the 40hz hump.
    I'll be doing more tweaking and when I add the bass traps I'll be sure to post if they made a difference, and how much each trap changed the response. If I put the subs in both one corner, I'll likely get to hear the odd order width resonances again that "could" help out the response, I'll have to try.
    As of now, the acoustic panels have eliminated "slap" echo and have reduced the ambient noise in my room a bit. A benefit of my room is I can easily adjust a 50hz and below response because there's no standing waves in that region. The worst part is the standing waves are in the "deep" vocal and upper bass region and have been noticeable during movies. (At least upper bass frequencies are easier to control than deep bass frequencies)
    Tomorrow I'll do the same sweep except at 100 decibels and see if I can get an easier to read response. I bed the roll off will change as well)
     
  2. Chris Tsutsui

    Chris Tsutsui Screenwriter

    Joined:
    Feb 1, 2002
    Messages:
    1,865
    Likes Received:
    0
    Ok today I did the same measurements at over 100 decibels (Loud! had to wear ear muffs)
    And the results are posted at my site in the 2nd thumbnail graph. Still a good extension down to 16hz I'm very proud of my cute tempests.
    Lets see if the picture hosting works with angelfire:
    [​IMG]
    All I can say is there was no distortion except for the window's bowing in and out at 20hz. The graph also doesn't look as intimidating as before and has a single dip precisely at the 1st order room modes of my room. Next week my tube traps should be finished and I'll see if I can even things out a bit.
     

Share This Page