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Which RSS265 should I go with?

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  • Which RSS265 should I go with?

    Mainly, will any of them be OK with a 400Hz crossover to a mid? Can the specs from PE and the FRD/ZMA files be trusted to gauge useable frequency range?

    Modifying a pair of Dahlquist DQ20 speakers I picked up missing the original woofers - which were an Advent-like 10" in a 12" basket with a masonite ring. If you aren't familiar with them, they're really nice speakers utilizing a slanted, time aligned open baffle for the mid and tweeter that sits on top of the woofer enclosure. The tweeter is a Scanspeak D2008 variant and the mid is a Magnat unit.

    Decided I'm going to go bi-amp and active between the woofer and mid.

    The cabinets measure in at 1.3 ft3 and they are sealed, and I would like an f3 into the 20s. I'll make a reducer ring to downsize the woofer cutout from the original driver to whatever the RSS265 needs. I can also either vent them, or go PR(maybe).

    I know the RSS series has been used as the bottom of a 3 way before, nothing new there, but from what I can tell they all crossed over to the mid no higher than 2-300Hz. I'd like to keep the mid section crossover intact and that is at 400Hz.

    Looking at just the specs provided by PE, it becomes obvious that I'll have to vent the enclosures and the HO-4 would work best, as after driver and vent displacement I should come out somewhere close to the 1 ft3 at 28Hz f3 that PE specs - but it also has the lowest specified useable range up top at 600Hz. With that, I could(although I'd prefer not to) cut out the back of the enclosure and add an extension to gain some internal volume to potentially accommodate the HF-4.

    According to PE-
    HO-44 - 1.5 ft3, 25Hz f3, 25-600Hz
    HO-4 - 1 ft3, 28Hz f3, 24-600Hz
    HF-4 - 1.5 ft3, 27Hz f3, 22-1000Hz
    HF-8 - 1.9 ft3, 23Hz f3, 25-2000Hz
    HE-22 - 1.5 ft3, 28Hz f3, 25-900

    The photos below aren't mine, just posting them up for reference.

    Click image for larger version

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  • #2
    The RSS210HF4 can play to 850Hz or just a bit higher. The HO4 has been used to 1kHz.

    Since this is the case, I would bet the 10" could extend to 600 since the 12" has extended to 400Hz.

    The range of a 10" is not something that should play to 2kHz for the most part, unless it's a low mass high Bl pro driver type. So, the 'range' stated really might not be a well suited spec that is likely to have been driven by suggested and not technically accurate ad copy.

    However, I would use the RSS265 with the lowest Le and Mms specs to try and achieve this easier. This means the HF4 is likely the best candidate on the higher end of bandwidth. It has fewer turns of coil, as well as a thinner cone.

    If you are going active as you say, use a small boost to get your F3 lower, and no need to add volume. Just make sure your output requirements do not require more than the woofer can give mechanically by breaching xmax.

    "Wolf, you shall now be known as "King of the Zip ties." -Pete00t
    "Wolf and speakers equivalent to Picasso and 'Blue'" -dantheman
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    • #3
      Going strictly by F3, I think the HO-4 and HE-22 will go the lowest in your size box.
      I'd use nothing smaller than a 3" "Precision Port", which means port length would be around 20" (and I'd prefer a 4").
      A PR will probably be your best bet.


      • #4
        Interesting. Well, going by Wolf's suggestion of choosing the one with the lowest Le and MMS, this would rule out both the HO-4 and the HE-22. Depending on which parameter is deemed more important for my use case, it's either the-

        HO-44 - .77Mh/161g
        HF-4 - .96Mh/120g
        HF-8 - 1.57Mh/131g

        HO-4 - 1.74Mh/201g​
        HE-22 - 2.1Mh/244g

        Kinda seems as the HF-4 may be the best choice.


        • #5
          Hf- 4 is a great woofer! Used a pair for years.