My 1st Sub Project

Discussion in 'Archived Threads 2001-2004' started by John_JLtZD, Dec 4, 2002.

  1. John_JLtZD

    John_JLtZD Extra

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    Hello,
    My name is John, I'll be attempting to construct my 1st speaker soon and I can definitely use advice.
    I'm starting with a subwoofer because that is what I most need. I used to use an old pair of pioneer tower speakers with 10" drivers as my mains and they worked well with subwoofer set to off on my JVC rx-884v receiver. I got a great deal on a pair of Infinity 2000.4's and used them as surrounds with a Cerwin Vega cc-240 as my center channel (tonal balance be damned [​IMG]. My original intent was to replace the Pioneer towers with a big pair of Infinities but that got axed soon after I upgraded my girlfriend to wife status.
    After we bought our 1st house the old school pioneers got exiled to the basement from where I fear they will never return. Which leaves the small infinities pulling front speaker duties and very little bass in my system. It took hooking the old pioneers up as temporary subs and playing a few DVD's to convince everyone involved that a dedicated subwoofer is desperately needed.
    I've been reading every DIY page I can find and I think I'm self-educated enough now to ask for advice and get started.
    I've decided to build a ported sonotube with a 12" driver based off of my room dimensions and my current system setup. I use my system 80/20, HT/Music.
    **The Room**
    http://www.digitalfarm.com/sonotube/room.jpg
    Placement of a large sub in my living room might prove tricky. The blue circles mark the two spots I can think of; 1 - a tall, top ported tube placed behind my entertainment center (which is a solid cabinet with doors) 2 - a shorter, wider, bottom ported tube used as an end table between my couch and an overstuffed chair. Both are in corners, 2 has more space around it but is positioned behind/beside the listeners, 1 is centered between my front speakers but crammed behind the cabinet.
    Any thoughts on which placement would work best would be greatly appreciated. I've even thought of taking the 10's out of the old pioneers and building a sealed box to put behind the entertainment center with the sonotube in position #2. I have an old stereo amp and equalizer I could use to drive them but really can't afford to put anymore money into a second sub aside from MDF and glue and I have no clue if that setup would sound right.
    **The Driver**
    I spent some time with WinISD and PartsExpress to find a 12" driver in my budget range. I've got around $200USD to spend on the Driver and the amp combined. I would have a little more but I need to buy a router/accessories and well, it's the holidays so I'm broke.
    The PartsExpress amp is $119 so that leaves about $80 to spend on the driver.
    I'm not sure that I'm using WinISD properly but here is what I came up with.
    http://www.digitalfarm.com/sonotube/gain_plot.jpg
    http://www.digitalfarm.com/sonotube/spl_plot.jpg
    http://www.digitalfarm.com/sonotube/box.jpg
    http://www.digitalfarm.com/sonotube/vents.jpg
    A) Is that a good gain plot?
    B) Is that an accurate gain plot for this driver in this box?
    C) What exactly is QI and what should I do with it in WinISD?
    D) Should I be tuning it to a lower frequency?
    E) Is there a better way?
    **The Tube**
    The diameter and length will be dictated by which of the two placements in the room makes the most sense. The plan is to use two layers of 3/4 mdf for the ends with a 1/4 sheet of plywood on the inside so that the T-nuts will have something to bite in to. Tons of liquid nails, silicon caulk, 'rope' caulk around the speaker, flared ports from partsexpress, a lot of wood glue, drywall screws, and a heavyduty terminal plate.
    I'm going keep the amp external in it's own box. The speaker is rated @ 220w rms, 8ohm, the amp specs state that it puts out 180w at 8ohm - should that be enough?
    **General**
    Should I spray the interior down with rubber? It sounds like a good idea and I read that the 'decron' will stick to it while it's still wet.
    When I calculate the internal volume do I want it to end up a bit shy of the desired mark due to the stuffing that will be lining the walls? I'm concerned that if I account for every internal element exactly that the stuffing will make the driver see it as being too big. If the stuffing can increase the effective size of the box by 40% is it safer to build it a little small?
    If I'm going to use stuffing should I build in a net to keep the stuffing off of the rear of the driver?
    Should I put in any 'poles' between the endcaps to help hold them on?
    If I use pannel connectors instead of T-nuts can I skip the layer of plywood?
    I've had some impressive systems at work so I _should_ be able to tell if it comes out right but the building is all new territory. Any help no matter how basic it may seem will be greatly appreciated. After this I'll need to upgrade that center channel [​IMG]
    Thanks in advance,
    John
    I would like to mention all of the people who have passively helped me along so far but it would be easier to just say that if you are cool enough to have posted step-by-step instructions I have probably read them and learned from you, so thanks
     
  2. Sreeni

    Sreeni Extra

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    John,
    I know this is not the advice you were expecting,[​IMG] but a couple of things..
    1. Please include dimensions of the room. It might provide some assistance to the experts here.
    2. If you can borrow a router/accessories, you might have more money for the driver/amp. There is no thing as "too much bass" [​IMG] [​IMG] [​IMG] [​IMG]
    Take care and good luck !
    Sreeni
     
  3. Ryan Schnacke

    Ryan Schnacke Supporting Actor

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    "I have an old stereo amp and equalizer I could use to drive them"

    "The PartsExpress amp is $119 so that leaves about $80 to spend on the driver."

    Am I missing something? Why wouldn't you use that amp with a PE driver? Then you could spend up to $200 on the driver - A DVC or Titanic Mk2 or even the new Stryke AV12 would fit that budget. You could always get a more powerful amp later.

    10 cu ft seems like a whole lot for a 12 inch driver. Shoot, the Tempest in the Adire alignment uses less than 8 cu ft. If the Peerless really needs that much volume I'd look for something else. If you really have that much room to work with I'd consider using your existing amp and building the Adire alignment Tempest. It wouldn't take a whole lot of power to get lots of SPL. And with stereo amp and dual voice coils you could run one amp channel to each coil.
     
  4. Jeremy Stockwell

    Jeremy Stockwell Supporting Actor

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    John, I think Ryan's right on track here. I'm building a Tempest sonotube now that I plan to power with an old Pro Logic receiver, at least temporarily. If you've got the room for the large enclosure and an old stereo amp to drive the Tempest, you're in good shape. You can get the Tempest for $150 shipped from Acoustic Visions. If you're set on a 12" driver, the Shiva is Tempest's little brother for $125 shipped.
    As far as room placement, it looks like either of the placement suggestions you mention would work. Determining which is best is something you'll have to figure out by experimenting in the room once you're done.
    JKS
     
  5. John_JLtZD

    John_JLtZD Extra

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    Thanks for the advice so far. I'll take some measurements of the room tonight, including the adjoining rooms since there is basically no wall dividing them.

    On the question of the amp, I'll have to check the model number when I get home but last time I checked I couldn't get any specs on how much power it puts out per channel. It's a pioneer receiver (**-510) from the 80's with the dual cassette decks/equilizer/tuner/amp all in one.

    It can handle an 8ohm load, but if I wire a big speaker per coil won't that be 4ohm?

    Aside from not knowing much about it (and not wanting to get in a situation where it isn't enough and I have to buy a new amp anyway), there is the issue of it's footprint (it's as big as many subs). If I put the sub in position #2 then I can leave the amp in position #1 but if position #1 makes more sense for the sub then there will be little room for the amp.

    Does anyone know of a site that has info on old receivers?

    If you can take a shot at answering some of my other basic questions I'd really appreciate it.

    thanks,

    John
     
  6. Ryan Schnacke

    Ryan Schnacke Supporting Actor

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    The tempest is 8 ohms per coil. Just connect one coil to each channel.

    If you decide you need a new amp and can only afford $80 for a driver, check out my thread regarding "$18 subwoofer drivers". You could put 2 of these in a 6 cu ft enclosure tuned to 26Hz.
     
  7. John_JLtZD

    John_JLtZD Extra

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    Ok,here are the room measurements to go with my pixel art:

    these should make sense if you look at the room.jpg and think of it like a 2D box.

    Height is 13' 4"

    width is 14' 4"

    Archway is 6' 2"

    the entranceway into the dining room is 9' 2" wide

    the dining room height is 11'

    the width of the room to the left is 6' 2"

    The distance from the back of the entertainment cabinet to the corner is 2' 8"


    Now back to the land of 3D:

    the ceiling is 8'

    ***

    I've been looking at the tempest and the 'Adire Alignment' ported box. This could fit well into position #2 with my old pioneer receiver (model RX-510) as the amp in position #1.

    Does anyone have the experience to compare a box built to the adire specs vs. a sonosub using the same driver?

    I'm still leary that a sub in position #2 won't sound right. I realize that low base is not directional but I'll want this guy to fill in the big gap left by the infinity mains. If I build it to spec it will only fit in position #2 so auditioning it around the room is not an option.

    I'm leaning towards this big driver with the old amp but I need to find out more about my reciever before I'm comfortable using it this way....I continue my quest for the manual.

    John
     
  8. Jon Torres

    Jon Torres Second Unit

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    I'm not sure if your receiver would be listed, but you could check out http://www.classicaudio.com. I'm currently powering my sealed dvc 15 w/ my dad's old pioneer qx-949a from the 70s and I don't like it very much. I think the pots have to be cleaned or something giving me uneven power. Today I ordered the PE 250 amp.
    I'd suggest picking up the PE 250 amp while it's on sale at $120 and free shipping. It ends Dec 31st. I thought about getting it from ebay, but I'd probably have to pay for shipping and it'd cost more. Then, I'd pick up the DVC 12 from ebay. I believe the reserve is around $80-85, so you could get it significantly cheaper than the website. So just stretch that budget out slightly.
     
  9. John_JLtZD

    John_JLtZD Extra

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    Thanks Jon,

    They don't have any listings post-1980 but there was some good info and a link to a site where people trade mauals that might really help.

    I noticed on the site that your amp is a quad with 4x40 or 2x60 (at least the qx-949 is). Do you know which way you have yours hooked up? When I finally track down some stats on the rx-510 I'll keep in mind your results.

    The PE 250 has a rumble filter (?) and auto-on (I actually know what that is and it's a nice feature to have) so I am definately tempted. It may mean a few more of my relatives go without gifts this year......sacrifices, sacrifices.

    JL

    - can anyone who has built the adire alignment and a sonosub with a tempest tell me the differences they've noticed?
     
  10. Jon Torres

    Jon Torres Second Unit

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    I believe I have it hooked up 2x60 giving me 120 watts. When the bass hits, sometimes one side is stronger than the other according to the receiver. I'm assuming I just need to clean the pots, but forget it... plate amp for me.
     
  11. John_JLtZD

    John_JLtZD Extra

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    Okay, perhaps I just needed a little push....

    I upped my budget some and ordered the Tempest driver and the PE 250w amp.

    After carefully considering the room placement I've decided the ported adire alignment will fit best.

    Sears was having a craftsman sale so I picked up the tablerouter combo pack and some carbide tipped bits. I've got a nice table saw and a 4" whole adapter for my drill so I'm just about ready to go.

    There have been many posts on building this sub so I'll try to keep my questions to the ones I can't solve by searching the board.

    For instance:

    Does anyone have any experience with giving their speakers that 'old skool routed panel' look? I would like for my sub to match my entertainment center and an old antique desk. Would there be any problems with routing out some panels and glueing them to the side of the speaker? Anything I should look out for?

    Thanks again,

    JL
     
  12. Owen Bartley

    Owen Bartley Second Unit

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    John, as far as the outer appearance of your sub, you can pretty much do anything you like as long as the construction is sturdy. Thats what I like about box subs vs. sonosub types. If you want, check out a few of the designs I've been playing with for my future Tempest at my site http://www.geocities.com/needfiles1/ (go to the sub page... duh! [​IMG] ) Then if you build furniture-style, you could pop it into the corner and 90% of people would just assume its a regular end table.
    Just a quick question, where is your crossover set from your mains to the sub? I'm not sure if it would make a huge difference or not in practice, but in theory, the sub would be less noticable in the far corner (position 2) if it were crossed over lower, say 80Hz vs. 100hz or so. Just an idea.
     

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