Using WinISD to model an Avatar 1x15

Discussion in 'Amps and Cabs [BG]' started by Soulfinger, Apr 19, 2005.

  1. Soulfinger


    Sep 20, 2004
    Houston, TX
    I want to get a 1x15 cab to add low-end heft to my rig. I'll probably get an Avatar, because they're built solidly, and I don't really care about the crossover and tweeter.

    I'm debating what speaker to put in it. I have an old 500 watt Carvin PS15C that's basically unused and has been collecting dust for years. I've been trying to use WinISD to try to determine if it would work well.

    Problems I'm having:

    I don't know the exact inner dimensions of the box--can anyone help me out?

    When I put in a square port of about the dimensions I think the Avatar box is (~23" x 1"), it says "too short" under port length. Am I doing something wrong?

    Does anybody have any general advice about this? Is this speaker worth it, or should I get an Eminence?

    Any input on this would be appreciated.
  2. Plain Old Me

    Plain Old Me

    Dec 14, 2004
    Maybe you should just get an Avatar 115 loaded with the Neo? I'm pretty sure they design their cabs digitally, but I may be wrong...
  3. I calculated the B115 to have about 4 cubic feet internally. I also calculate the shelf port as 2 ports because of the center bracing that splits it in half. Each half measures 2 x 11 x 7.
  4. Petebass


    Dec 22, 2002
    QLD Australia
    I have a link which shows the T/S parameters of the PS15c speaker.

    Notice the 4 and 8 ohm versions have slightly different T/S specs so make sure you plug the right ones into WinISD. It should be pretty easy from here if you use Muzikman's calculated internal volume and port info.
  5. Soulfinger


    Sep 20, 2004
    Houston, TX
    Thanks for the help on this. Win ISD shows that the cab is tuned at ~ 50 hz, and the Carvin speaker should work fine in that box, with a fairly flat response and -3 dB at ~53 Hz.

    The Kappa LF does it bit better, with -3dB at ~47 Hz.

    The Deltalite currently standard from Avatar actually looks pretty poor. It's -3 dB at 56 Hz, with a fairly uneven response, resulting in a big spike in the mid-bass between about 85 and 120 Hz.

    Of course, this is all on paper, and may or may not "sound good" in the real world.

    Can anyone recommend any 15" drivers with particularly deep response?
  6. Avatar uses a one-size-fits-all, and this cabinet appears to be:

    22.625 x 22.625 x 12.625" internal = 3.74 cubic feet
    slot port = 22.625 x 8.625 x 2.0"

    [ edit ]
    These measurements were provided by a TB'er who owns the 2x12 Avatar. I plugged them into my design sheet and got 3.44 net cubic feet after subtracting driver displacement. Tuning is 48.4 Hz on paper, right close to the claimed 50 Hz tuning of this box.
    [ /edit ]

    Subtract the displacement of the driver from 3.74 to get the net internal volume. This is typically 0.15 cubic feet for a 15" driver. This gives an internal volume of about 3.6 cubic feet. It is a simple matter to use my spread sheet to find a driver with a Vb of this volume.

    The Kappa 15LF is a perfect match and the Legend CB15 is very close.

    Link to B115-03 with Kappa 15LF Plans
  7. Soulfinger


    Sep 20, 2004
    Houston, TX
    Thanks for your input. I had previously downloaded your spreadsheet. It is a valuable resource.

    Also, thanks for your numbers on the Avatar box. I had previously been modeling assuming a 4 ft^3 volume with a 7" deep port.
  8. My b115 and b212 cabs do indeed have different sized ports. The b115 is 7 inches and the b212 is 9 inches. The box size calculations you provided do not include the fact that there is space behind the port. I did round off my numbers and don't remember them offhand. I also didn't calculate for driver displacement.
  9. The screen shot I gave for the link to my design spread sheet calculates port volume, cleat displacement, bracing, etc, etc, etc. The exact volume particulars are in the link.

    I was very thorough when I wrote it.
  10. Petebass


    Dec 22, 2002
    QLD Australia
    Bruce the link isn't working.