Focal Sibs vs Polk RTiA3

Discussion in 'Speakers' started by chupacabra, Oct 7, 2012.

  1. schan1269

    schan1269 HTF Expert
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    Subwoofers are the easiest place to start.
    IF you screw the sub together and use glue you can separate with heat, you can rebuild the sub if it isn't quite right.
    The "basic guideline" is the size of the box is "square" based on the size of the driver...
    15" driver needs an 18" square INNER DIMENSION box. Internal bracing is dependent on "how much air can this sub move"...
    IF you buy a sub with an enormous VC and magnet, and pump 1000 watts into it, you need to brace the box to keep the sub from "sucking it in"...
    Robert J just helped a guy build a box(the thread is here somewhere, if I find it before you do, I'll link the thread) based on Q and everything else. If you buy existing subs(like these CV D8) where finding out its "properties" is near impossible...you start with a square box. If you need to, you make numerous sides with different size holes for different lengths/thickness of PVC for the port. If you keep it Acoustic Suspension, you need a "slightly bigger" box, than you need with porting.
     
  2. schan1269

    schan1269 HTF Expert
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    Found the thread. Lots of fluff in certain areas, but there are mentions of other places to look for calculations for to build the right size box...
    And again about bracing, there is no such thing as too much...
    http://www.hometheaterforum.com/t/322897/anyone-in-sav-ga-area-to-help-with-sub-box
     
  3. Robert_J

    Robert_J Lead Actor

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    I like to go a step above Sam's basic guidelines. It will work about 90% of the time but I like to be a little more accurate with my plans and predicting the outcome.
    On the other hand, there are a lot of different subs that will go into existing enclosure plans. For example, the Subduction driver hasn't been on the market for years but the TC Sounds Epic above will work in both of these boxes - http://creativesound.ca/pdf/SubDuction-plans-290307.pdf . Same thing with the plans from Dan Marx. The TC Sounds Axis (same as the TC 3000) is available and will drop right into this - http://www.danmarx.org/audioinnovation/tc3000.html . If that's too much to spend, then the 15" Dayton driver will work with this - http://www.danmarx.org/audioinnovation/tcsounds.html even though the original design was for a TC Sounds 15".
    As you can see, TC Sounds and Dayton were both mentioned above. Parts Express has a lot of different drivers available at many price points but there are many others that work. The Alpine Type R (old or new model) work great also. In fact, I picked up some blown Type R's and plan on rebuilding them using this kit - http://www.springfieldspeakerstore.com/shop/article_1TR12RC-D2-3-2/Alpine-12%22-SWR-1221D-Subwoofer-Recone-Kit.html?sessid=CuRiWcMztPKUlSn26wkp6gjcW4NXlktnt9Eoe3O7emMkhHVviB9Amc5rHOU7GxiT&shop_param=cid%3D114%26aid%3D1TR12RC-D2-3-2%26 .
     
  4. schan1269

    schan1269 HTF Expert
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    Last time I built my own sub...the sacrificial lamb was an old EV box...
    Then I just had to make the front. It was simple since I wanted Acoustic Suspension anyway. The only thing I did "different" was a "dual" set-up.
    I chose two 8" drivers and the actual outer was a 10" radiator.
    Polk did that design many times, and was the idea behind what I did.
     
  5. chupacabra

    chupacabra Extra

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    How about a used sub from flea bay? Any good suggestions on what may be a really nice sub that cost more when new and I could now pick up used in the $500-$750 range?
     
  6. schan1269

    schan1269 HTF Expert
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    Craigslist is where I'd start. Shipping a sub eats most of the "savings"...
     
  7. chupacabra

    chupacabra Extra

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    Hi Robert,
    Other than the TC sounds axis mentioned above, is there another less expensive driver that would drop into this box? http://www.danmarx.org/audioinnovation/tc3000.html That looks like something I would be comfortable building as my first attempt. Also, what amp would you recommend to go with the driver?
    Thanks again for all the help!
    Cliff
     
  8. chupacabra

    chupacabra Extra

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    I was wondering if anyone had any opinions on wether or not this would be a good material for bass traps.
    http://www.ebay.com/itm/4-x-27-x-82-Foam-Rubber-Sheet-Cushion-Replacement-/310491197429?pt=LH_DefaultDomain_0&hash=item484ab7aff5
    Even if this may not the absolute perfect material, if the edges were cut to 45 degree angles, so as to be stood up in a corner and appear to be flat at a 45 degree angle to the walls forming a corner, could one expect to have a significant bass trapping effect?
    [​IMG]
    How about these?
    Any advice/opinions greatly appreciate!
    Thank you in advance
    Sent from my SAMSUNG-SGH-I777 using Tapatalk 2
     
  9. Robert_J

    Robert_J Lead Actor

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    I have never built a bass trap. I have read where some guys use rolls of insulation with no backing. I've never seen that material mentioned but I haven't read much about traps either.
     
  10. Robert_J

    Robert_J Lead Actor

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    The Dayton DVC has been around for years and I've used the 12" version in a couple of subs for family members - http://www.parts-express.com/pe/showdetl.cfm?partnumber=295-190 Just read the reviews on it.
    Pair it up with a 250 to 300w plate amp and you will have more sub than 90% of the other home theater enthusiasts.
     
  11. Dave Upton

    Dave Upton Owner
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    I wouldn't use that for bass trapping without some serious research. Bass traps work because of the density of the material (it's unique absorptive capabilities) and sheer volume - meaning it has to be several inches thick before you see a noticeable "bass trapping" effect. I strongly recommend this excellent article at GIK Acoustics about how bass traps work so you can better understand your goals for building your own. http://www.gikacoustics.com/news_081610.html

    Finally, if DIY is your style, then I highly recommend the SuperChunk style bass trap, described here and shown below: http://www.ayoung.ca/basstraps.html

    http://www.google.com/url?source=imglanding&ct=img&q=http://cdn.avsforum.com/1/10/106847da_vbattach223724.jpeg&sa=X&ei=-96OUNnKNsbVqgHr_ICABQ&ved=0CAkQ8wc&usg=AFQjCNExF0Qi8JGuI7eOyVWELxFIzSuz9Q


    Or, you can build a conventional 4" panel trap: http://www.radford.edu/~shelm/acoustics/bass-traps.html
     

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