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2 pronged question...2inch peerless and ideas on how to finish 3d print.

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  • #16
    Originally posted by neildavis View Post
    If you are referring to the JAB-3+ board, you could program it's ADAU1701 to provide several bass enhancement functions, any of which could help overcome the limitations of the small volume. The Linkwitz Transform or conventional bass boost will provide more low frequency output, but they don't help much if you are constrained by the cone excursion limits. However, the ADI Superbass algorithm generates harmonics that give the impression of deeper bass without requiring more cone excursion. Superbass can sound "fake" and distorted if turned up too far, but at moderate levels it can be fairly effective without sounding fake.

    Programming the ADAU1701 would require either putting the DSP code into the JAB-3+ EEPROM with a SigmaStudio programmer, or else you could add a CPU board to control the DSP. If you use the CPU board, you could control all of the parameters (such as the intensity or frequency of the Superbass) from a cell phone app. The CPU board is that white area in the picture with the OLED display--it doesn't take up much space at all, and it has built-in Bluetooth to receive commands from the cell phone app. There are only 5 wires to connect: power, ground, SDA, SCL and WP, and they are all on J5 of the JAB-3+. I've got some of these boards and I'll get the software finished once I can get back to doing fun stuff. The phone app software can control the bass enhancement functions on a "generic" ADAU1701 board, but the JAB-3+ has some special issues that I haven't addressed yet.
    I grabbed this random one with adjustable pots on it to tweak the DSP, but haven't done any research into it, just know it's adjustable. About a year ago I looked into the LT circuit trying to get something small that helped me get that Bose SoundLink mini bass and performance, but truth be told i found it quite intimidating and didn't pursue it any further due to lack of knowledge and the introduction of those small amp modules
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    • #17
      That amp would be great for an active two-way speaker with programmable crossover, BSC, EQ, and bass enhancement. You would need to program the EEPROM that is on that board with the SigmaStudio code. Or, you can add that microprocessor board and it will program the ADAU1701 and the EEPROM for you, and provide a high-level Bluetooth interface for real-time DSP control. As I said, I've got working code for the ADAU1701, but the Wondom board has a unique challenge, in that it is designed for battery-operation and it powers down the DSP when there is no audio activity. I haven't written the code to deal with that issue yet, but it isn't difficult.

      Yep, there is still the intimidating issue of programming the microprocessor board, but if there is enough interest we might get someone to sell pre-programmed boards that would convert these nice amps into great active 2-way amps. That would give the DIY community a really nice building block for active speakers with enough DSP power to compensate for small cabinets. I know someone who interested in providing that type of product, but I can't help make that happen until the work on my house is complete. We are trying to sell this place, and I've still got lot of refurbishment to do...
      Free Passive Speaker Designer Lite (PSD-Lite) --