DIY Stereo Subwoofer Project

Early B.
Early B. Posts: 7,900
edited January 2009 in DIY, Mods & Tweaks
Now that my center channel is completed, I'm thinking of building a pair of passive stereo subwoofer towers to straddle my TV. I had a set of DIY stereo subs about a year ago, but when we re-arranged the room, the subs were put away in the basement.

I have two 10" Ascendant Audio drivers available. I can also power them from two unused channels on my HT amp like I did before, and I have the crossover, as well. All I really need to do is build a couple of cabinets.

I believe these are the specs for the driver:

• DUAL 4 OHM COILS
• R 3.35 Ohms per coil (6.7 Ohms measured in series)
• Fs 33.8 Hz
• Qms 4.68
• Qes .43
• Qts .39
• Mms 123 g
• Sd 310 cm^2
• Vas 24.24 l
• SPL 85.2 1W/1m
• BL 20.2
• Xmax 18mm
• RMS 500W


The width of the box needs to be less than 12" in order for them to fit. The boxes can be 36" tall and 16" deep or whatever makes sense given the specs. The subs are for music, so they don't need to hit 20Hz flat. However, I would like for them to flat into the high 20's, if possible. I'm confident the drivers can do the job, especially since they're gonna be housed in bigger boxes than before.

What do you guys think?
HT/2-channel Rig: Sony 50” LCD TV; Toshiba HD-A2 DVD player; Emotiva LMC-1 pre/pro; Rogue Audio M-120 monoblocks (modded); Placette RVC; Emotiva LPA-1 amp; Bada HD-22 tube CDP (modded); VMPS Tower II SE (fronts); DIY Clearwave Dynamic 4CC (center); Wharfedale Opus Tri-Surrounds (rear); and VMPS 215 sub

"God grooves with tubes."
Post edited by Early B. on
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Comments

  • Face
    Face Posts: 14,340
    edited January 2009
    With a Fs of 33.8 Hz, you can't tune them in the 20's.

    Using WinISD, it recommends a box of .764 ft3(cubic feet) with a tune of 34.55hz.

    With a box 12" wide, you can build them 15" tall and 10" deep, 12.7 tall and 12.7 deep, 10" tall and 16" deep, etc... If you want to go narrower, 11.5 x 12.5 x 13.5 would work too.

    http://www.linearteam.dk/default.aspx?pageid=winisd
    "He who fights with monsters should look to it that he himself does not become a monster. And when you gaze long into an abyss the abyss also gazes into you." Friedrich Nietzsche
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  • Early B.
    Early B. Posts: 7,900
    edited January 2009
    Face wrote: »
    With a Fs of 33.8 Hz, you can't tune them in the 20's.

    How much should I tack on for room gain? A few hz, right? Both subs will be surrounded on three sides, so it may help out a lot.
    HT/2-channel Rig: Sony 50” LCD TV; Toshiba HD-A2 DVD player; Emotiva LMC-1 pre/pro; Rogue Audio M-120 monoblocks (modded); Placette RVC; Emotiva LPA-1 amp; Bada HD-22 tube CDP (modded); VMPS Tower II SE (fronts); DIY Clearwave Dynamic 4CC (center); Wharfedale Opus Tri-Surrounds (rear); and VMPS 215 sub

    "God grooves with tubes."
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  • Early B.
    Early B. Posts: 7,900
    edited January 2009
    Got another question -- is it possible to run these subs for both HT and 2-channel?

    I'm thinking of running a pair of y-adapters from the input of the crossover: one set of ICs will go to the stereo outs on the HT preamp and the other set of ICs will go to the second set of outputs on the CDP. (NOTE: I only have one set of inputs on my 2-channel pre. I have run a sub direct from the CDP in the past with good results.)

    Of course, the HT and 2-channel systems will never be "on" at the same time.

    Thanks.
    HT/2-channel Rig: Sony 50” LCD TV; Toshiba HD-A2 DVD player; Emotiva LMC-1 pre/pro; Rogue Audio M-120 monoblocks (modded); Placette RVC; Emotiva LPA-1 amp; Bada HD-22 tube CDP (modded); VMPS Tower II SE (fronts); DIY Clearwave Dynamic 4CC (center); Wharfedale Opus Tri-Surrounds (rear); and VMPS 215 sub

    "God grooves with tubes."
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  • Face
    Face Posts: 14,340
    edited January 2009
    IMO, that doesn't sound like a good idea.

    Doesn't your HT and 2 channel setup share the same mains? There must be another way to hook things up. Does your 2 channel pre have a HT bypass?
    "He who fights with monsters should look to it that he himself does not become a monster. And when you gaze long into an abyss the abyss also gazes into you." Friedrich Nietzsche
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  • Early B.
    Early B. Posts: 7,900
    edited January 2009
    Face wrote: »
    IMO, that doesn't sound like a good idea.

    Doesn't your HT and 2 channel setup share the same mains? There must be another way to hook things up. Does your 2 channel pre have a HT bypass?


    My 2-channel pre has one set of inputs and one set of outputs. That's it.
    HT/2-channel Rig: Sony 50” LCD TV; Toshiba HD-A2 DVD player; Emotiva LMC-1 pre/pro; Rogue Audio M-120 monoblocks (modded); Placette RVC; Emotiva LPA-1 amp; Bada HD-22 tube CDP (modded); VMPS Tower II SE (fronts); DIY Clearwave Dynamic 4CC (center); Wharfedale Opus Tri-Surrounds (rear); and VMPS 215 sub

    "God grooves with tubes."
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  • Face
    Face Posts: 14,340
    edited January 2009
    Do both rigs share the same set of mains?

    Do you have a thread or diagram on how your rig is set up?
    "He who fights with monsters should look to it that he himself does not become a monster. And when you gaze long into an abyss the abyss also gazes into you." Friedrich Nietzsche
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  • Early B.
    Early B. Posts: 7,900
    edited January 2009
    Face wrote: »
    Do both rigs share the same set of mains?

    Do you have a thread or diagram on how your rig is set up?

    Yeah, both rigs share the same mains. I got speaker cables running from my HT amp and 2-chanel amps, so I manually connect the respective speaker cables to the speakers. That's it. I keeps it simple.
    HT/2-channel Rig: Sony 50” LCD TV; Toshiba HD-A2 DVD player; Emotiva LMC-1 pre/pro; Rogue Audio M-120 monoblocks (modded); Placette RVC; Emotiva LPA-1 amp; Bada HD-22 tube CDP (modded); VMPS Tower II SE (fronts); DIY Clearwave Dynamic 4CC (center); Wharfedale Opus Tri-Surrounds (rear); and VMPS 215 sub

    "God grooves with tubes."
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  • Systems
    Systems Posts: 14,873
    edited January 2009
    Early B. wrote: »
    How much should I tack on for room gain? A few hz, right? Both subs will be surrounded on three sides, so it may help out a lot.
    Each boundry will add approx 3 db of boost so you can factor in about 9db.Also room gain inreases with decreasing frequency so yes you can tack on a few extra hz of usable output below the predicted -3 point of the sub.
    Early B. wrote: »
    HT preamp and the other set of ICs will go to the second set of outputs on the CDP. (NOTE: I only have one set of inputs on my 2-channel pre. I have run a sub direct from the CDP in the past with good results.)
    By running the sub directly off of the output of the CDP you will not have any way to adjust its level.It would getting the full output from the CDP all the time.



    Aswell you will need to connect both the coils (on each driver) in series unless your amp can comfortably drive 2 ohms.
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  • Early B.
    Early B. Posts: 7,900
    edited January 2009
    GV#27 wrote: »
    By running the sub directly off of the output of the CDP you will not have any way to adjust its level.It would getting the full output from the CDP all the time.

    My crossover has volume control. It will sit between the CDP and subs. Will that work?
    HT/2-channel Rig: Sony 50” LCD TV; Toshiba HD-A2 DVD player; Emotiva LMC-1 pre/pro; Rogue Audio M-120 monoblocks (modded); Placette RVC; Emotiva LPA-1 amp; Bada HD-22 tube CDP (modded); VMPS Tower II SE (fronts); DIY Clearwave Dynamic 4CC (center); Wharfedale Opus Tri-Surrounds (rear); and VMPS 215 sub

    "God grooves with tubes."
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  • Early B.
    Early B. Posts: 7,900
    edited January 2009
    GV#27 wrote: »
    Aswell you will need to connect both the coils (on each driver) in series unless your amp can comfortably drive 2 ohms.

    No need to. Each sub will be powered by a separate channel on the HT amp.
    HT/2-channel Rig: Sony 50” LCD TV; Toshiba HD-A2 DVD player; Emotiva LMC-1 pre/pro; Rogue Audio M-120 monoblocks (modded); Placette RVC; Emotiva LPA-1 amp; Bada HD-22 tube CDP (modded); VMPS Tower II SE (fronts); DIY Clearwave Dynamic 4CC (center); Wharfedale Opus Tri-Surrounds (rear); and VMPS 215 sub

    "God grooves with tubes."
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  • Systems
    Systems Posts: 14,873
    edited January 2009
    Early B. wrote: »
    My crossover has volume control. It will sit between the CDP and subs. Will that work?
    But then you will always have adjust it when you change the main volume control,that would be a pain.


    Are you still using a passive pre?
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  • Systems
    Systems Posts: 14,873
    edited January 2009
    Early B. wrote: »
    No need to. Each sub will be powered by a separate channel on the HT amp.
    Yes but each driver has 2 voice coils.Both coils should be connected,so you will end up with either 2 ohms paralell or 8 ohms series for each one.
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  • Early B.
    Early B. Posts: 7,900
    edited January 2009
    GV#27 wrote: »
    Are you still using a passive pre?

    Yep.
    HT/2-channel Rig: Sony 50” LCD TV; Toshiba HD-A2 DVD player; Emotiva LMC-1 pre/pro; Rogue Audio M-120 monoblocks (modded); Placette RVC; Emotiva LPA-1 amp; Bada HD-22 tube CDP (modded); VMPS Tower II SE (fronts); DIY Clearwave Dynamic 4CC (center); Wharfedale Opus Tri-Surrounds (rear); and VMPS 215 sub

    "God grooves with tubes."
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