SDA-1A vs. SDA-2 specifications

machone
machone Posts: 1,510
in Vintage Speakers
With very similar schematics why do the specifications for the SDA-1A show crossover frequencies at 50, 125 and 2500 and the SDA-2 only at 50 and 2500?
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Best Answer

  • Schurkey
    Schurkey Posts: 2,101
    Answer ✓
    Looking at the schematics on this site for the 1A and the SDA 2, the only difference I see is that the 1A has two "bass drivers" and a smaller inductor, while the SDA 2 has a single "bass driver" and a larger inductor.

    Assuming that the inductor value is chosen to match the different number of "bass drivers", I'd expect the crossover points to be identical. Since the crossover points in hz are not listed on the schematics, I'm guessing that the crossover points you've found are more a result of the advertising department than the engineering department, and the "ad men" made a mistake.

    My take on the crossover points:
    50 hz is the onset of the PR taking over from the "bass driver(s)"
    125 hz is where the bass driver(s) cross to the single mid-woofer
    2500 hz is where the single mid-woofer crosses to the tweeter.

    I suppose the SDA side uses the same 2500 hz cross from SDA mid-woofer to SDA tweeter.
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