Two AV12's or One AV15?

Discussion in 'Home Theater Projects' started by Troy R, Aug 11, 2003.

  1. Troy R

    Troy R Stunt Coordinator

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    I've been messing around with WIN ISD and WIN ISD Pro, and have been throwing around the idea of making my own sub. I want a sub that can do both HT and music with music being the MOST important. I want the extension of a vented sub so I am probably going vented. I want the least amount of distortion possible so I was thinking multiple drivers... something simlar to the SVS PB2+ tuned a little lower. so I originally came up with two AV12's in a 250 liter box tuned to 18hz. Then I ran the same box and tune with a single AV15 and it appears to be very similar...

    My question is would I see any benefits from using two AV12 drivers instead of one AV15? My ultimate goal is low distortion, with great extension and "musical" bass...

    Also, would this design compete with the SVS PB2+? (which I got to hear over the weekend and was VERY impressed!) I'd probably get a Samson S1000 or S700 to power the sub.

    Any insight would be great! Thanks!
     
  2. Bryan Michael

    Bryan Michael Supporting Actor

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    dual av15 on the samson do i av15 now and one later.
     
  3. ThomasW

    ThomasW Cinematographer

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    A pair of AV12's will give you a Sd of ~1000 sq cm and have a list price of $350. A single AV15 has an Sd of 802 sq cm and has a list price of $205.

    So if you have the bucks a pair of AV12's will outplay a single AV15.

    But for the $60 bucks difference I'd vote for a pair of AV15's
     
  4. Joel X

    Joel X Stunt Coordinator

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    I would say go with dual for one reason, it is possible to mount the speakers in one enclosure opposing each other, canceling out vibration. And perhaps if you subscribe to the theory that the driver motor is not perfect then you will also have one of them mounted basket side out to allow for the motor of each speaker to drive opposite directions and cancel distortion.
     
  5. Troy R

    Troy R Stunt Coordinator

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    Thanks guys!

    I figured everyone would probably tell me to get two AV15's instead! [​IMG]

    I'm in an apartment for at least another 8 months or so depending on how the job hunt goes for my future wife. So dual AV 15's would be WAY too large, and probably get me kicked out pretty quick, heck one AV15 could probably get me kicked out.

    We'll see what I can come up with in the coming months! But when I move into a house, LOOK OUT!

    Thanks again!
     
  6. Troy R

    Troy R Stunt Coordinator

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    Oh, another question for you experts...

    The volume of my sub design comes out to 250 liters (about 8.829 cu ft). According to this Polyfill Chart if I stuff the box with about 9 pounds of polyfill can I reduce the size of the box to about 190 liters?

    Thanks!
    Troy
     
  7. ThomasW

    ThomasW Cinematographer

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    Personally I don't use damping to 'fudge' volumes. I build the box to the size calculated by the software, then use the damping to fine tune the overall performance characteristics.

    I certainly wouldn't recommend trying to 'create' 60L of volume with poly (regardless of what it shows on Nousaine's website). If you want to decrease the volume 5-10% that should work.
     
  8. Troy R

    Troy R Stunt Coordinator

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    Thanks Thomas! that does make more sense than hoping the polyfill makes up for the lost volume.
     
  9. Frank Carter

    Frank Carter Screenwriter

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    If you get a single driver and a Samson amp, make sure to only run it off a single channel or find an amp that is 2 ohm stable. Samson recommends not to bridge the amps or you can damage them, I found this out the hard way[​IMG].

    Here's one more thing to consider, two AV12's will need a slightly smaller enclosure than a single AV15.
     
  10. Shawn Solar

    Shawn Solar Supporting Actor

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    The enclosure size is a big deal for me. I just bought(and recieved today[​IMG] ) my two av12's. I'm planning a cube each with a LT and 400watts each. I currently have a bp1503 in a 5ft^3 sonotube and it is a bit of an eye sore. Plus the av12's are shiny, my favourite colour[​IMG] if you have the room I'd go for the dual 15's.

    This is getting out of hand. I got 5 subs sitting on the floor and a centre channel to build along with bass traps in the works. Troy, once you build your first you'll be planning a second[​IMG]

    A plate amp would work well for a single sub. for more than one I would use a two channel pro amp or a bridged pro-amp with a 4 ohm load.
     
  11. Troy R

    Troy R Stunt Coordinator

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    Thanks for the help guys! I REALLY want to build my own sub but I'm more of a two channel guy and I keep running into problems on deciding how to hook up a DIY sub. For speaker level connections Plate amps usually don't have enough juice to power the subs. If I go the pro amp route then I have to find a way to crossover. And I'm trying to decide if I want an integrated amp (have to use speaker level connection to sub) or seperates. What a pain this hobby is!
     
  12. Shawn Solar

    Shawn Solar Supporting Actor

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    Troy,

    there are plate amps that range from 100-1000+watts. Usaully just more expensive than a equivelent pro-amp. Although pro-amps lack the crossovers and such. Kiega, bash and rythmic to name a few. adire has a few as well.
     
  13. Allen Ross

    Allen Ross Supporting Actor

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    your receiver might have a OX point for the sub out
     
  14. Troy R

    Troy R Stunt Coordinator

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  15. Shawn Solar

    Shawn Solar Supporting Actor

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    For a two channel setup I'd prefer the sub crossed a little lower than for HT. I think 50-60hz for the sub would be great. A paradigm x30 would be fine for a pro-amp. I have a similar setup. I run a QSC amp in conjuntion with a energy eac crossover. The energy crossover has high level and line level inputs/outputs and has a variable crossover for both high and low pass and phase and such. They are discontinued but a good find.

    Bash amps are also at acoustic visions.
     
  16. Troy R

    Troy R Stunt Coordinator

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    Thanks Shawn. I'm still not finding Bash amps on acoustic visions, maybe I'm blind or not looking hard enough...

    There's a paradigm X30 on audiogon right now for $85. too bad I am in the middle of a deal for a pre amp...
     
  17. Shawn Solar

    Shawn Solar Supporting Actor

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    Sorry Troy,

    I didn't see them either at acoustic visions. Maybe he dropped them for kiega or something. I also need another crossover as my av12's will be used with my mains and therefore my mains need a high pass and my subs a lowpass.
     
  18. Brett DiMichele

    Brett DiMichele Producer

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    "For speaker level connections Plate amps usually don't have enough juice to power the subs"


    *scratches head* This statement has me confused????

    An amplifiers job is to do nothing other than "Amplify" the
    signal it's fed..

    Speaker Level (High Level) Inputs would actually have a
    higher voltage going in than RCA (Low Level) and if anything
    the amp would probably need the gain turned down more using
    Speaker Level due to the higher nature of the signal. That
    is assuming there is no filtering added on the input side
    of the High Level input.

    A good plate amp will do it's job the same on high or low
    level inputs, the only major benefit of low level is much
    reduced room for 60hz hum because the speaker wires can be
    far more suseptable to absorbing emi from nearby equipment
    power wires than a low level sheilded rca would.
     
  19. Troy R

    Troy R Stunt Coordinator

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    oops, sorry. What I meant is I didn't know there were so many plate amps out there that had enough juice to power an stryke woofer to it's maximum capabilities.

    I was thinking of getting an integrated amp. If I got an integrated I would have to use a plate amp for the speaker level connections (if I wanted to crossover my mains). Now that I know there are plate amps out there with a lot of power most of my concerns are taken care of.
     
  20. George W

    George W Stunt Coordinator

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