Subwoofer for 8" Designs

Discussion in 'DIY Speakers and Subwoofers' started by Hollywood, Jun 14, 2013.

  1. Hi,

    So I didn't high jack this thread,

    I thought I would start a new one, basically I'm looking for a DIY sub to go with the Minions as LCR, or if the budget starts getting hammered the Fusion 8's.

    15" seems to be the sweet spot, and as suggested by mtg90, the gets rave reviews, however after a few days reading I think I prefer the the HO's brother, the HF,

    HO= High output
    HF= High fidelity

    By all reports the
    HF seems to like a larger enclosure,and in an effort to appease the WAF, trying to get the smallest enclosure whilst still getting the best out of the driver seems to be the challenge.

    So I just asked mtg this question, Sorry, are you saying put the HF in the 3cuft box unported, or in the ported 4cuft or unported 4cuft?

    I've been doing lots of reading over the last few days, and I think the HF will be a better fit for me, re music. I could get the 4cuft box and make my own front baffle if need be.

    He also said this, The 15" RS HF would be a better choice if the port will not fit in the 3cuft, but you loose about a dB above 40hz and about 5dB at 25hz."

    I'm ok with loosing a few dB's here and there if it means a smaller enclosure.
  2. I don't know much about this, so I want to fill in some details about what it seems like you're suggesting, and check with someone who knows if they're right. I really like the idea of a 3cuft box if that's a good choice. I'm not in exactly the same boat as you, Hollywood, since I'll be looking at probably 4 for HT use (maybe 2 for starting).

    PE's woofer selection guide ( shows specs that include:
    Dayton Audio - RSS390HF-4
    part# 295-468
    RMS power 500W
    optimum sealed volume 2.88cuft
    sealed f3=37Hz
    fr resp 18-800Hz

    So with the driver displacing a little, and then some poly or something a 3cuft box get's you pretty close to the 2.88 their program recommends. Down 3db at 37 Hz and assuming second order sealed roll-off (12dB/oct) you're down 15dB or so at 18Hz, which PE lists as the bottom.

    How does this translate into real SPL? I would assume that 500W RMS program material would generate a lot of distortion, right? (like more than 10%? so is 500W a practical clean limit, or should you really drive it with less, like 300W?)

  3. HopefulFred,

    My use is a mix of music/movies with a bias towards music. The other thing which I neglected to tell mtg was that it's ok for me not to have the amp on/in the enclosure as all of my equipment will be rack mounted, in my office. So that could free up a little internal volume in the enclosure.

    From what I've been reading seems like if you match the amp power rating with the speaker RMS you should be fine, just dont go overboard, if anything a little under.

    If I can get the HF into the 4cuft enclosure either ported or sealed that would be good, I just dont have the space to go bigger, I like the ported one mtg did, but I prefer a cube shape with rounded corners, hopefully mtg will see this and offer his expertise, hint hint.
  5. Subwoofer for 8" De

    I think probably for anything remotely audible at those frequencies with that budget, its going to have to be a DIY job with LOTS of power behind it, only problem you then have is port tuning, youll have to tune it so low that the upper frequencies will then suffer. I use a Dali E-12F myself, all I listen to is DNB and it does the job.

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