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Avatar SB126 mod question

Discussion in 'Amps and Cabs [BG]' started by A-train, Apr 11, 2021.

  1. A-train


    Nov 22, 2005
    San Antonio,Tx
    I know many of you have either owned an Avatar SB126 or modded a SB112 so I have a couple of questions for you guys. My SB126 is the Alpha 6/ Delta12lf setup but I recall Avatar used to offer a 1.6K crossover frequency as an option. I happen to have an old Eminence PBX 1.6K crossover from back when Eminence used to sell them cabinet ready. I've thought about swapping out the Avatar crossover for this but wonder if this mod be worth doing? I plan on putting in an Eminence 3012lf down the road and I know that speaker starts to fall off frequency wise much sooner than the Delta. I did a search for this but didn't see much except for one other guy doing this. The other thing I was wondering about is if I do put in a 3012lf should I consider blocking a port to lower the tuning?
  2. 808State


    Dec 30, 2020
    Delta 12LF has a Fs of 51 Hz
    so i would only guess he is high tuned to 55 to 60 Hz

    So yes with a Fs of 37 Hz for the 3012LF
    You would want to lower the tuning.

    Plugging one port is a option. You would have to calculate to know.
    Problem is that the air velocity of one port might be too high.

    Other option would be to buy new ports that fit the current cut outs and use a longer port

    PBX 1.6K crossover is 18dB slope I believe
    im not sure if you need such a high crossover and slope.
    Doesn't hurt to listen.

    You could cross over at 1.6k or experiment with very simple 6 dB slopes
    if you want such a high crossover point.
    Simple as one capacitor
  3. I have the SB126, and several 1.6k Eminence crossovers in stock.

    Mine is the same driver configuration as yours... for a specific reason.
    Dave (Avatar) tells me that Jerry McNutt (Eminence) does the design work for Avatar.
    This means the cabs are properly sized and tuned for the drivers being used.

    Changing woofers that are different than the design woofer will change the response.
    Guessing at plugging port tubes is asking for more changes in response.

    I bought the COTS 12LF because it is a standard item that can be replaced easily.
    It is not one of the proprietary Neo drivers that MUST be bought from Avatar should you need one.
    The sealed back 6-inch is also commercial off the shelf, and easily replaced.

    The 12LF is a sturdy driver that does what it is intended to do.
    I use them in bass horns which place FAR more stress on the driver than a vented box does.
    IMO, please resist the urge to tinker... just play the box as-is, or sell it for something else.
    jeff7bass likes this.
  4. jeff7bass


    Apr 9, 2009
    I agree. Not a fan of modding cabs, especially when they are already good like the SB126. Better off selling it and buying another cab if you want more power handling or different frequency response.
  5. A-train


    Nov 22, 2005
    San Antonio,Tx
    I can see the logic in that but the things I'm asking are things that Avatar used to offer as options already so I dont know if it would be considered tinkering. Avatar used to offer the 3012lf and 1.6K crossover as options for this very box. The crossover point is what I'm more interested in than the woofer. My cab has the standard crossover that Avatar uses for all of it's 2 way bass cabs which I believe crosses over at 3k or so and so I wanted to hear from others who have the 1.6k crossover if it makes a difference in the mid presence of the cab since the mid driver would take over at a lower frequency
    jeff7bass and Passinwind like this.
  6. IIRC, the SB126 uses the COTS Alpha 6cmbr sealed back 6-inch drive.
    Its' data sheet shows response from 400 Hz to 5 KHz, +/- 2.5 dB.
    This lends itself very well to the Eminence 1.6k crossover.

    I am interested in this because the 12LF is quite directional above 1350 Hz.
    Crossing the 12LF over at 1.6k creates less of an off-axis response loss.
    The 12LF is mostly flat to this frequency, with a sharp spike above, then rapid falloff.

    3012LF response rises above flat from 600 to 1800 Hz, then falls like a rock.
    This driver is also designed for a much smaller box volume than 12LF.
  7. A-train


    Nov 22, 2005
    San Antonio,Tx
    This cab actually started as an SB112 because I had two of them. Dave from Avatar is the one who sent me the 6 inch mid and instructed me on how to jump one resistor like they currently do for the 126 so if I get the cab builders assistance to mod a cab I would say its ok. He mentioned that they don't offer the 3012lf or 1.6K crossover anymore because they've streamlined their offerings so since I already have an Eminence 1.6K crossover I wanted to hear from someone who purchased one when Avatar offered those options to see how they like it compared to the options now.
    Passinwind and jeff7bass like this.
  8. A-train


    Nov 22, 2005
    San Antonio,Tx
    Thanks bgavin! That's some great info there. So I will leave the Delta12lf as is since the box is designed around that driver but it sounds like think going to the 1.6k crossover could be beneficial if the Delta12 starts to beam around 1.3k.
  9. A-train


    Nov 22, 2005
    San Antonio,Tx
    By the way gents, this is just going to be used simply as a stage monitor for myself and not expected to carry the room. That would be a lot to ask of a single 12. I play in mid to large rooms with a loud a metal band and set this up as a side shot for myself and the drummer. The PA takes care of the room and I haven't been able to get the band to embrace in-ears yet so I've been scaling down my own rig and trying to find something just loud enough. I'm using a SansAmp VTRM into a crown XLS 1500.
  10. Beaming calculations start with the piston diameter.
    The actual directional characteristics are additionally affected by the cone shape, the dome type, etc.
    12LF is fully omni directional up to 339 Hz.
    It is calculated to be fully "beaming" by 1356 Hz.

    If this is a monitor, make sure it is elevated or aimed so you both are on-axis.
    It is pointless to aim a monitor at your knees.
    HaphAsSard likes this.
  11. A-train


    Nov 22, 2005
    San Antonio,Tx
    I actually set it up as a side shot angled back towards me and the drummer and not behind me. I also live in the low mid to mid range tone wise and not scooped or super deep. I find this cuts better and doesn't compete with the bass drum or guitars for those frequencies.
    HaphAsSard likes this.
  12. A-train


    Nov 22, 2005
    San Antonio,Tx
    So after taking all the advice given by you guys I left the Delta12LF driver in my SB126 but I did switch the crossover to the Eminence 1.6 from the stock Avatar crossover. I find that I like the sound of the cab much more like this than with it crossing over at 3k like the old one used to. Previously it seemed like there was a hint of harshness in the driver around 2/2.5k that I didn't like that seems to have gone away now that the 6 inch mid takes over before that. The cab seems to now have a much more flat response to it.
    Doufuss likes this.
  13. Nice!
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