The MemX DIY procrastination thread - 4 SI18s in 11 cubic feet?

Discussion in 'DIY Speaker & Subwoofer Building' started by MemX, Aug 4, 2013.

  1. MemX

    MemX
    Well-known Member

    Joined:
    Feb 15, 2013
    Messages:
    3,724
    Products Owned:
    1
    Products Wanted:
    0
    Trophy Points:
    133
    Ratings:
    +1,206
    Hey all!

    As I'm sure most of you are already aware, I am terrible for procrastination and take fooooreevveerrrr to actually make a decision on what I could do for a DIY sub. :blush: :rolleyes: :laugh:

    I do love my SVS PB12-Plus/2 but I'm aware it's not got that mid-range punch of others, does not dig that deep below tuning (16Hz with two ports plugged, although it is pretty floor shaking at times!) and does not have as much output as I would like at the low end.

    Inspired by everyone else's excellent builds I have been thinking about replacing the SVS with something a bit bonkers - do it once, do it right, and all that jazz :)


    I have therefore been playing with WinISD now I have (finally!!) got it to work on this knackered old laptop at home, and think I've worked out a box that might be ok?

    So, I would welcome your feedback on the following attachments!! :)

    I'm thinking 4xSI18s, a CV5000, 11 cu ft sealed...

    It 'feels' like it might be a bit small, with each driver only seeing 2.75 cu ft rather than the 6 cu ft needed for Qtc of 0.707, but the power would be there from the CV5000 and the graphs appear to show that XMax of c.22.5mm would only be reached at just about 4Hz, with XMech of 35mm / 43mm (Databass estimated measurements / SI ratings) reached at between 1.5 and 2Hz, which shouldn't be a problem because the amp starts roll off at 5Hz, I believe, and room gain should provide a half-decent boost (6-10dB on a good day??).

    I think the 8033 can boost down to 5Hz as well, so that could be an option? (I can't work out how to apply a boost in WinISD :facepalm:)


    Anyway, any thoughts are much appreciated! :)
     
    Last edited: Aug 5, 2013
  2. mojogoes

    mojogoes
    Remembered (1961-2016)

    Joined:
    Oct 12, 2007
    Messages:
    10,469
    Products Owned:
    1
    Products Wanted:
    0
    Trophy Points:
    166
    Location:
    Faraneverland
    Ratings:
    +1,984
    Are you thinking of putting 4 drivers into one enclosure sealed!.
     
  3. MemX

    MemX
    Well-known Member

    Joined:
    Feb 15, 2013
    Messages:
    3,724
    Products Owned:
    1
    Products Wanted:
    0
    Trophy Points:
    133
    Ratings:
    +1,206
    Either in one enclosure in a 2 FF, 2 DF, Push-pull set up, or split it into two boxes, each a push-pull like a KK.

    The latter would at least mean I could move it if I needed to... :laugh:
     
  4. mojogoes

    mojogoes
    Remembered (1961-2016)

    Joined:
    Oct 12, 2007
    Messages:
    10,469
    Products Owned:
    1
    Products Wanted:
    0
    Trophy Points:
    166
    Location:
    Faraneverland
    Ratings:
    +1,984
    I would keep it a little more simpler than that and just go with x2 fi sp418's or q18's in there own enclosures either using x1 cv5000's or x2 cv5000's if you go with the sp418's.............I think you'll be well happy with there output and what they will be able to do.
     
  5. MemX

    MemX
    Well-known Member

    Joined:
    Feb 15, 2013
    Messages:
    3,724
    Products Owned:
    1
    Products Wanted:
    0
    Trophy Points:
    133
    Ratings:
    +1,206
    I had been thinking about the Q and SP4 options but I think I can't afford them :(

    Also, I think I get a larger displacement with 4 SIs than 2 Qs or SP4s, but I will need to check my workings tomorrow at work.

    I have the space for a larger box as well so if the SIs work out cheaper (I think they do) then I might as well use the space and save a bit of money! lol


    I've just cross-posted this on AVS as well, so I will be interested to see what the multi-driver crazy americans will think of my suggestion :D :laugh:
     
  6. W124coupe

    W124coupe
    Active Member

    Joined:
    Dec 27, 2006
    Messages:
    614
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    28
    Ratings:
    +58
    Have you had a proper shipping quote on the SIs and factored in duty, VAT and courier brokerage fee?
     
  7. Jameskatie

    Jameskatie
    Distinguished Member

    Joined:
    Jan 2, 2013
    Messages:
    4,134
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    166
    Ratings:
    +2,102
    Irene Scene - Door Flex
    look at that guys channel you won't be disappointed with SI18 and will get cleaner sound than the fi
     
    • Thanks Thanks x 1
    • Funny Funny x 1
    • List
  8. mojogoes

    mojogoes
    Remembered (1961-2016)

    Joined:
    Oct 12, 2007
    Messages:
    10,469
    Products Owned:
    1
    Products Wanted:
    0
    Trophy Points:
    166
    Location:
    Faraneverland
    Ratings:
    +1,984
    WOW.................get a room:rotfl:
     
  9. MemX

    MemX
    Well-known Member

    Joined:
    Feb 15, 2013
    Messages:
    3,724
    Products Owned:
    1
    Products Wanted:
    0
    Trophy Points:
    133
    Ratings:
    +1,206
    I'm waiting to hear back from SI with a definite figure but I've had indicative costings from a kind person who's already done it and let me know the total costs after shipping and import charges etc were added :)


    Ah, popalock's build... I am aware of him from AVS! Crazy build, I didn't realise he was using SIs!
     
  10. MemX

    MemX
    Well-known Member

    Joined:
    Feb 15, 2013
    Messages:
    3,724
    Products Owned:
    1
    Products Wanted:
    0
    Trophy Points:
    133
    Ratings:
    +1,206
    Right, have remodelled into 15 cu ft with XMax at around 7Hz, and think I will work around that :)


    Electronics roll off through the chain would (hopefully!) ensure I didn't really go much over XMax below that, if at all, and the larger size would release a little more output :) And hopefully room gain (+12dB per octave as you decrease in Hz?) would bump the bottom end up again!


    Annoyingly there is a CV5000 up on ebay for £550 that is apparently pretty much brand new, but it's the other end of the country and collection only :facepalm: lol
     
  11. ewizzy

    ewizzy
    Well-known Member

    Joined:
    Feb 24, 2012
    Messages:
    1,440
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    86
    Location:
    St Ives
    Ratings:
    +391
    Where abouts in the country? Maybe a member slightly closer could help you out?
     
  12. MemX

    MemX
    Well-known Member

    Joined:
    Feb 15, 2013
    Messages:
    3,724
    Products Owned:
    1
    Products Wanted:
    0
    Trophy Points:
    133
    Ratings:
    +1,206
    The amp is in Hull!

    That's a major trek down to the south of the country, and I'm not sure I'd trust Parcelfarce or similar to deliver it in one piece if I could arrange collection and forwarding by some nice person... especially when I won't be able to test it before it arrived!


    I will have to hang on and see what else comes up, I think :)
     
  13. Jameskatie

    Jameskatie
    Distinguished Member

    Joined:
    Jan 2, 2013
    Messages:
    4,134
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    166
    Ratings:
    +2,102
    im in hull
     
  14. Jameskatie

    Jameskatie
    Distinguished Member

    Joined:
    Jan 2, 2013
    Messages:
    4,134
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    166
    Ratings:
    +2,102
    my uncle is a private courior and travels all over, where abouts are you?
     
  15. ewizzy

    ewizzy
    Well-known Member

    Joined:
    Feb 24, 2012
    Messages:
    1,440
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    86
    Location:
    St Ives
    Ratings:
    +391
    See, there you go :thumbsup:
     
  16. mojogoes

    mojogoes
    Remembered (1961-2016)

    Joined:
    Oct 12, 2007
    Messages:
    10,469
    Products Owned:
    1
    Products Wanted:
    0
    Trophy Points:
    166
    Location:
    Faraneverland
    Ratings:
    +1,984
    I reckon they would take £400 for that as I thought you could buy them for £550 new.
     
  17. MemX

    MemX
    Well-known Member

    Joined:
    Feb 15, 2013
    Messages:
    3,724
    Products Owned:
    1
    Products Wanted:
    0
    Trophy Points:
    133
    Ratings:
    +1,206
    I'm not sure - I haven't seen them for less than £600, and that was B-Stock...



    Cool! :)

    PM sent ;)
     
  18. mojogoes

    mojogoes
    Remembered (1961-2016)

    Joined:
    Oct 12, 2007
    Messages:
    10,469
    Products Owned:
    1
    Products Wanted:
    0
    Trophy Points:
    166
    Location:
    Faraneverland
    Ratings:
    +1,984
    Was it you that bought the cv5000 on ebay for £485......................if so a good buy:)
     
    Last edited: Aug 7, 2013
  19. scottthehat

    scottthehat
    Distinguished Member

    Joined:
    Jan 6, 2012
    Messages:
    11,160
    Products Owned:
    2
    Products Wanted:
    0
    Trophy Points:
    167
    Location:
    honiton
    Ratings:
    +2,801
    it should be a mental amp for sure, I have the cv2800 and its awesome and runs my 2x 15 ae subs with no probs, but it weighs a bit 22kgs and the cv weighs even more, they are made like tanks.
    if you get it im sure you will be more than happy.
     
  20. batfink007

    batfink007
    Active Member

    Joined:
    Jan 18, 2009
    Messages:
    151
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    31
    Ratings:
    +33
    Get those SI18s ordered so I have another build thread to read when I'm back from holiday!!!
    :)
     
  21. MemX

    MemX
    Well-known Member

    Joined:
    Feb 15, 2013
    Messages:
    3,724
    Products Owned:
    1
    Products Wanted:
    0
    Trophy Points:
    133
    Ratings:
    +1,206
    Am awaiting a quote from SI re: shipping - I think they've been moving this past week or so and the guy needs to ring fedex to get quotes for all the international orders! I'm hoping they come in at around what you got yours for :)



    I wish! :(

    I have got my eye on some B-Stock locally for around £600 but they are out of stock...


    I think the CV5000 is 37.5kg or so :eek:

    It's also a Class H amp so I fear for the heat it will produce and also my electric bill... :rolleyes: It is +/- 0.5dB 5Hz-25kHz, and +/- 3dB 5Hz-34.5kHz, so I'm hopeful that it won't have too much roll off below 5Hz so I can get that ULF output the best I can :)


    Going from what I've found on other sites, it looks to be basically identical (if perhaps specced slightly lower :eek:) than an American Audio V-6001. These seem to be going for much the same price new, so if I have to buy New then it would appear there are options... :)

    The LG 'clone' amp is another option that appears to be monstrous (4400w per channel @ 4Ohms, 7000w per channel at 2Ohms :eek:) but I don't trust the reliability...
     
  22. scottthehat

    scottthehat
    Distinguished Member

    Joined:
    Jan 6, 2012
    Messages:
    11,160
    Products Owned:
    2
    Products Wanted:
    0
    Trophy Points:
    167
    Location:
    honiton
    Ratings:
    +2,801
    I did see a guy who had tried a few and then got a cv and he said there was no comparsion, I had my doubts after running an nu3000 bridged(2200w rms) the nu3000 wouldn't run both my subs of its own channel but the cv will with ease, and runs each sub the nu3000 did bridged, well worth the money in my eyes.
    yeah my cv2800 does get hot but I don't worry about it now its on all day and no problems and if it costs me to enjoy it so be it, its worth it.
     
  23. MemX

    MemX
    Well-known Member

    Joined:
    Feb 15, 2013
    Messages:
    3,724
    Products Owned:
    1
    Products Wanted:
    0
    Trophy Points:
    133
    Ratings:
    +1,206
    Sounds good! :) My electric bill seems to rise regardless of what I do so I might as well enjoy what I do use :p lol


    Have uploaded below the revised WinISD graphs of the 15 cubic feet box instead of the 11 cu ft - hopefully it is accurate and system roll off will counteract the rise in excursion below 8Hz!
     
  24. MemX

    MemX
    Well-known Member

    Joined:
    Feb 15, 2013
    Messages:
    3,724
    Products Owned:
    1
    Products Wanted:
    0
    Trophy Points:
    133
    Ratings:
    +1,206
    Oh, and to aid visualisation of the alcove where any subs will have to go, either side by side, stacked on top of each other, or just as one big box, please see a badly drawn, not to scale, missing most things but includes the important things and their rough positions, drawing! :p
     

    Attached Files:

  25. MemX

    MemX
    Well-known Member

    Joined:
    Feb 15, 2013
    Messages:
    3,724
    Products Owned:
    1
    Products Wanted:
    0
    Trophy Points:
    133
    Ratings:
    +1,206
    Scott, have you had to swap fans on the CV2800? I'm wondering how noisy CV5000 fans might be, given it will surely get quite hot... lol
     
  26. scottthehat

    scottthehat
    Distinguished Member

    Joined:
    Jan 6, 2012
    Messages:
    11,160
    Products Owned:
    2
    Products Wanted:
    0
    Trophy Points:
    167
    Location:
    honiton
    Ratings:
    +2,801
    Yes I have they where noisy as. But there 24v so I used 12v and my own supply.
    You can get a step down transformer which you can solder in place if you wish.
    If you look in my build thread you will see last page.
     
  27. MemX

    MemX
    Well-known Member

    Joined:
    Feb 15, 2013
    Messages:
    3,724
    Products Owned:
    1
    Products Wanted:
    0
    Trophy Points:
    133
    Ratings:
    +1,206
    Thanks for the confirmation :)

    I worry about warranties so may see if I can tuck it away or put some noise-absorbing material on surrounding services near the back of it!
     
  28. scottthehat

    scottthehat
    Distinguished Member

    Joined:
    Jan 6, 2012
    Messages:
    11,160
    Products Owned:
    2
    Products Wanted:
    0
    Trophy Points:
    167
    Location:
    honiton
    Ratings:
    +2,801
    its easy mate, all you do is buy one of the converters which are a couple or quid,
    desolder the wires of the fan so you can put them back on if you want to put original fans back in, then solder that to the stepdown trany then solder your 12v fans of that, it really is simple, you only need one transformer and solder both 12v fans to that, so you only need to desolder one fans wires and just disconnect the other fan.

    you can even but quiet 24v fans but there like £20 a pop.

    I fit 12v fans where the 24v ones where and a 12v 60mm fan at the front on one side as that side gets warmer.
    [​IMG]
     
  29. MemX

    MemX
    Well-known Member

    Joined:
    Feb 15, 2013
    Messages:
    3,724
    Products Owned:
    1
    Products Wanted:
    0
    Trophy Points:
    133
    Ratings:
    +1,206
    That sounds complicated for someone with zero proper DIY skills :p lol
     
  30. scottthehat

    scottthehat
    Distinguished Member

    Joined:
    Jan 6, 2012
    Messages:
    11,160
    Products Owned:
    2
    Products Wanted:
    0
    Trophy Points:
    167
    Location:
    honiton
    Ratings:
    +2,801
    mate it aint and I know you can do it, do you know anyone that's good with a solder its a 5 min job.
     

Share This Page

Loading...