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Active 3 way ...

Dispensing with the intro, hi everyone, my latest project is a three way using a 10" PHL mid-bass, a Volt 75mm mid dome and a Seas 1" dome tweeter. The PHL will cover from ~ 70Hz up to 500Hz. The Volt goes from 500 HZ to ~ 3,500 and the Seas does the top bit. The PHL will be boxed, though @ 20 litres the volume is so small it's not really possible to fit the rest in. Perhaps handy though, as I'm thinking it's smart to make cabinets that don't need an army of muscle-men to move around. So, the idea is for the mid and tweeter to share a common mount while the 10" has a separate box and anything below that also has its own home.

Amps ... a mixture. Class D for the 10" [will this work noiselessly with my inverter?], an audio GD SA100, 2X100W for the Volts and maybe my venerable Aksa 55N+ for the tweeters.

Undecided: form of active X-over. I had been thinking of using the ESP option but I get the impression, that by the time I've bought a set of reasonable components, it won't actually be all that cheap while requiring a partial rebuild to use for anything else, so, maybe a minidsp.

As a bit of background, I've had a solar stand-alone power supply for more than twenty years. Lately it's got a bit bigger but it does set limitations on the amount of power I can splurge. In many ways it's an ultra clean supply though it does use a high speed switching inverter to give me 240 AC from 24V DC. Thus, the sine wave output is a compound of many, many small steps rather than being absolutely pure. Does this matter? Not so far.

Given I was getting ready to fight a fire last week but now it's preparation for flooding, things are a bit busy around here so the project might have to wait for a bit, though I've got the various bits together.




  • Welcome!!

    I now have a pair of surplus AKSA 100 N+ modules and a power supply if it helps...went for a NAKSA80 upgrade recently. Is good.

  • Hi Jules, glad you could make it! Is the Audio GD the class A one you were working on a while back?

  • Jules, the main problem with an analogue crossover is that you need to be able to design and build custom filters. It's far more than just high and low pass filters. A passive crossover is more powerful than that and will sound better. DSP allows you to use EQ as well.

  • Thanks Seano, I'm hoping to get away with the 55N+s but it's a tempting offer.

    John, well no, that class A would use something like 300W per channel which is way above what I can afford to use, at night anyway. I still have to send my CAD design off for cutting and bending though all that's needed there is spending a bit of money. Maybe when I retire to the city?

    The audio-gd amp is a diamond differential circuit intended to be used with a fairly heavy class A bias. I picked up quite a few audio-gd bits and pieces early in their life when semi-kits [and cheap "burson" buffers] were available.

    Paul, yes, a passive designed by a guru would be the ultimate I guess, but while there's all sorts of basic "calculators" around to do the job, I reckon anything I could make myself would be pretty average. DSP, sure ...


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