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Long post - RSS265HO vented or something else?

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  • Long post - RSS265HO vented or something else?

    Hello all, I live a vicarious speaker-building life through this forum and have lurked here for many years. We moved to a larger house a couple of years ago and the 15-year old Logitech z-5500 system (I know!) I set up in our old, very small living room ended up in a ~4,500 cu ft room. The power supply in the amp module finally gave up last week. I'm not so sad, as the SQ was perfectly acceptable for the age/price, but marginal at best in the large room. I've since purchased a b-stock Denon AVR-920W and have it rigged up with a grab bag of speakers from my basement (Cambridge Soundworks Ensemble II satellites & Cambridge Audio SX-70 center, plus two of the old satellites from the z-5500 for rear surrounds). A Dayton Sub-1000 is doing temp duty on the low end. Considering my small investment and all the "rules" I'm breaking, it sounds pretty good post-Audessey correction. We don't typically watch movies at high volume, which helps.

    I'd like to build a reasonably capable (f3 ~25 hz), relatively small (~ 1.5 cu ft) sub. Target budget is $200 to $250 minus finishing and amp. I have a Yung 300w (no boost) amp from an aborted project for my brother that I can use, so I was looking for design options. This one will eventually go to my 13 year old son, but will be in the large room for a couple of years.It looks like the RSS265HO is relatively flexible on box size in a vented alignment, but I'm looking for opinions and any experience the folks here might have with that driver. The HF looks like it needs a huge box unless run sealed. I have basic woodworking skills and tools (minus a router), but would be happy if I could use one of PE's knock down cabinet options. I know the room wants multiple subs or a much larger single, but that's not in the cards in the short-term. We won't be pushing it too hard (until my son gets his hand on it).

    The preliminary WINISD modeling I did with the current T/S parameters suggest a long port (~36 inches) for alignments in the neighborhood of 1.3 to 1.5 cu ft. Am I off track in thinking the RSS265HO is a good option? Are there better options I'm missing?

    Thanks for any input and my apologies for the looong post!


  • #2
    Your model SEEMs accurate. With: Qts=0.35, Fs=27, and Vas=1.04cf, I see a 4"id x 36"long port yielding an F3 in the mid 20s in 1.3 net cu.ft. using YOUR Y300 w/an 80Hz LP point.

    While a 4"id port is usually my choice for a 10" or 12" sub, you COULD probably get by using a 3" "Precision Port" (20" is about right) if your SPL requirements aren't that intense.

    The 265HF-4 could work in the 2cf sub box w/a 3" PPort that's 14" long for an F3 in the mid 20s. Straight, it might just (almost) fit in that box.

    Another way to shoehorn too large of a sub in too small of a (vented) box is to use a slot port (more complicated), or a passive radiator (ka-ching$).


    • #3
      Thanks for the response, Chris. That's close to what I'm seeing. A 36" port would require 3-4 elbows and take up quite a bit of the interior volume. I looked at the 3" option, but assumed the chuffing would be audible.

      I'll play around in sketch up to evaluate the slot port options. Much appreciated.