BG Neo3 / Betsy / Eminence Alpha 15 A MK III

The MK II version was lacking in the treble region. I have added a tweeter and fidled with the crossover.

The tweeter is a BG Neo-3, the midrange is a Wildburro Audio Betsy and the 2 woofers are Eminence Alpha 15A.

The system is tri-amplified fully active using a Behringer DCX 2496 crossover, a Behringer iNuke 3000 DSP (modified) for the bass, a DIY chipamp for midrange and a DIY Tubelab SSE for the tweeters, a passive DIY volume control / source selector and a line driver from Abacus.

The crossover points are:

  • Low pass 200 Hz, 18dB Butterworth
  • Band pass 200 Hz – 2000 Hz 18 dB Butterworth
  • High pass 2000 Hz 24 dB Butterworth
  • No EQ is used

The overall frequency response is very good. Needless to say, that the sound is very lovely indeed. This one is a keeper!


Response 70cm in front Crossover response ca 70cm in front Response 70 cm from the back crossover response from back FrontandBack

10 thoughts on “BG Neo3 / Betsy / Eminence Alpha 15 A MK III”

  1. Hi, nice build. Wish I had a room that size to go with my alpha15a open baffles. I understand you simulated the slot. Could you please say what the sim suggested?

  2. Hi Mickael,
    Did I miss something on your posts about the special design of the front of your O.B ? Why did you set this two boards on the woofers ? I guess there an incidence on the basses ?
    Thank you very much,
    Kind regards,

    1. Hi Nicolas,

      The slot loading adds a bit of air mass to the cone of the woofer. It lowers the FS a bit and also acts as a low pass filter. Nelson Pass did slot loading for one of his projects as well. I copied my design from Hifiakademie Dipol speaker.

      Kind regards


      1. Wanted to try this way of slot loading on 8 inch woofers in an array of 4 each side. Is there a way to understand how much low pass I can expect at what frequency?

  3. I see you move your project from 1 Eminence Alpha 15inch to 2 drivers per side. Can you tell me what is the biggest difference when you have 2 vs 1 of 15inch drivers? I have 1 Eminence Alpha 15 inch per side and I find the bass is not good enough. It is quite loud, but not good. I am thinking of buying 1 more pair. But then I have to redo the baffle again.
    And do you do any EQ in your miniDSP for the system?

    1. 2 bass drivers won’t make it better, just louder. You get about 3db more SPL in the bass. What made it better vs. my earlier approach was the slot loading. These days I also employ a small boost at 40 Hz to give it a bit more bottom end. Ultimately, a better driver is most likely the ones made by Acoustic Elegance. They are, however, at a completely different price point.

  4. Hello!! can you give specifics about the baffle? I have 4 Alphas and would like to make your project if you do not mind…

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