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Powering subwoofer - need some clarification.

Discussion in 'General Hardware' started by selway89, Aug 17, 2009.

  1. KH0UJ

    KH0UJ New Member

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    No offense bro but the additional capacitor in series with the 2.6 Kilo ohms resistor will not sound the sub the way it should be, i think you can only hear 1% of the high frequency sound on it even if you full the volume of a 1000 watt rms amp. no bass, no mid, 2.6K is so high that it limits the current of the output which is needed on the low frequency response of a typical sub.
     
  2. selway89

    selway89

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    Thanks for all the info! Greatly appreciated. Building my own box is very appealing.

    I think one of these drivers http://cgi.ebay.co.uk/ws/eBayISAPI....159524&ssPageName=STRK:MEWAX:IT#ht_5014wt_939 which is from a Mission M6AS subwoofer http://www.hifix.co.uk/sku2.lasso?item=8e033768313ac87ade763a625a8743c2 in a simple infinite baffle 30L cab might do the job.
    The speaker it's self is 8ohm so fine for my amp on a single channel, should just be a case of converting the stereo signal to mono before the amp, possibly the need for a simple crossover circuit to tune the cutoff range.

    edit. the reason why I chose the mission driver is mainly due to the fact my main speakers are mission and may provide to be a better match, also not overly keen on car based speakers.
     
  3. KH0UJ

    KH0UJ New Member

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    what is really your target frequency on your sound system bro?:)

    cause what i understand on sub woofer frequency is from 10 hz to 60 hz and it can only be heard or be precisely produced if you`re using a low impedance speaker (1 ohm-4 ohms) 8 ohms speakers can also produce that frequencies but the intensity of the 30 Hz sound output on a 4 ohms speaker is louder than 8 ohms.
     
    Last edited: Aug 18, 2009
  4. selway89

    selway89

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    The M30i speakers have response of 68-20000Hz so just want to get the lower end of the scale. Just to enhance movies films and games, if it works like the bose did when I had that working then that will be fantastic.
    Overall volume isn't a huge concern as it will be working with the Cyrus amp around 25W per channel.
     
  5. KH0UJ

    KH0UJ New Member

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    how about a double voice coil speaker which is 8 ohms + 8 ohms 10 inches in diameter 60 watts, if you can make the box by yourself i can give you dimensions and ways on how to tune it using only your amp and a 33 Hz mp3 reference signal and play it on your computer in loop while tuning the tuning ports to achieve optimum intensity.
     
    selway89 says thanks.
  6. selway89

    selway89

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    Fantastic, sounds good. Open to ideas. :)
     
  7. KH0UJ

    KH0UJ New Member

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    so its not a sub frequency, it`s a mid bass:) which is really easy to calibrate;) a tip also on the speaker selection, dont buy a speaker which is way too much wattage capacity, its just a waste of $, your amp is only 25 Watts, a 30 watts speaker capacity can do the job and is more cheaper than the higher watt capacity speakers, same like a PSU on a PC, if your PC only consumes 250W, a 300w or 450w can do the job for a cheaper than buying 700 Watts.
     
  8. selway89

    selway89

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    True, only reason why I selected that Mission model is that it's easy to get hold of, should be easily driven from my amp, and the subwoofer produced by mission has a given spec of 30L infinite baffle cab which will be easy to make.

    Found this too on my searches http://diyaudioprojects.com/Speakers/MAW-10/MAW-10.htm how relevant that cab is to the mission speaker I'm unsure but overall product looks great :D

    Have my 5th star too now :D
     
  9. KH0UJ

    KH0UJ New Member

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    alright then:) let me draw first all the dimensions, procedures, and everything:laugh: maybe ill post it tomorrow, this is one of my ways to make my stars go up:laugh: right now its only 4 stars:banghead:

    Moderators: can i post a PC sound system construction procedure here on TPU? i mean its still computer related topic cause its for PC:eek:
     
  10. KH0UJ

    KH0UJ New Member

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  11. selway89

    selway89

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    Yes it is, idea is to build an infinite baffle 30L cab with that mission speaker. Rather than having it powered internally I should be able to use my Teac amp with the speaker rated at 8ohm which effectively is the same.
     
  12. KH0UJ

    KH0UJ New Member

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    so you mean to say you wanna buy the M6AS subwoofer system and condemn the active amp. and use your teac amp?:confused: im totally confused bro, kindly elaborate:)
     
  13. selway89

    selway89

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  14. KH0UJ

    KH0UJ New Member

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  15. selway89

    selway89

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    That size is for the M6AS as a whole. Just need a 30L (1.05ft3) cab so for a infinite baffle something like 12"x12"x12" should be plenty I think. Or I could use the dimensions from this http://diyaudioprojects.com/Speakers/MAW-10/MAW-10.htm and make it a ported cab.
     
  16. dr emulator (madmax)

    dr emulator (madmax)

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    yes but he was buying a powered sub so ohmage is not to much of a concern:rolleyes: hm yes capacitors well it was 1:30 am did you expect a rembrandt :laugh::roll::laugh::D oh and that circuit was out of a 20watt system minus caps:p : dam if it'd been a few months earlier he could have had my sony subwoofer for free as it was to big (was given away to a charity shop i think) [​IMG]
     
  17. KH0UJ

    KH0UJ New Member

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    12"X12"X12" can accomodate a nice response on a mid bass frequency, but if you prefer a slightly intensed bass production, go for a ported type on the MAW-10 dimensions, just replace the square tuning pipes with a PVC 3" in that way its easy for you to tune it, but i think you only need 8"inch long by 3"inch in diameter to begin with on both sides cause its 68 HZ you are tuning. slowly cut it by 1"inch each and every tune you made, set the volume on your amp. to half while calibrating the maximum intensity of the bass, the only problem is you need a signal generator software on PC to produce 68 HZ, i have it the last time, it`s a trial version but it works just for tuning though:rolleyes:
     
  18. selway89

    selway89

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    I were thinking that the MAW-10 looked like a good template for the mission driver. The good thing with the reflex port is I could tune it slightly as you say and the distance from a wall could also adjust how it sounds.

    That design takes into account the driver size (wont be exactly same) and the plate amp, but I could make it an inch or two shorter, but then again I'v read cabs slightly bigger than required help with the lower end.

    Off to the garage to see what wood there is laying around. :p

    Id like to thank all for their help.
     
  19. KH0UJ

    KH0UJ New Member

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    Ived just found the signal generator freeware, http://www.brothersoft.com/mini-signal-generator-160327.html , just run it and type 68 HZ on the frequency sinewave then press save to and set it to 5 minutes so that its longer .wav file enough for you to tune and cut, may the modding force be with you and good luck on your construction:rockout:
     
  20. KH0UJ

    KH0UJ New Member

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    ohh i almost forgot, about the Db meter, just do it the conventional way, set the volume to halfway, play the 68 HZ sinewave .wav file, position the box and listen to it 30 feet away, i know its not accurate but its a quick calibration, but if you prefer the high tech way, you need a laptop with mic and download this http://www.softpedia.com/progDownload/Zelscope-Download-89785.html , (Zelscope 1.00) its a PC oscilloscope using the mic as a sensor, in that way you are sure about the intensity you are measuring, its a trial version though but mine`s fullware hehehe, put it 10 feet apart from the soundbox you are tuning, and put it steady and also the volume of the amp while seeing the different intensities of each cut.
     
    Last edited: Aug 18, 2009
  21. pantherx12

    pantherx12 New Member

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    Didn't know there was so many people into speakers on here :D

    I had to do it all on my lonesome : [

    Your speakers are going to be grand.

    Makes me want to buy 8 speakers ( 2 subs 2 tweeters and 4 mids) and build two cabinets he he he
     
  22. selway89

    selway89

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    Haha. I think a audio sub forum should be somewhere, there are a couple of threads dedicated to audio but nowhere really for them.

    For my first attempt I'll be putting that mahoosive mission 10" sub in a 12"x12"x12" infinite reflex cab to see how it sounds, and then maybe attempt a reflex ported cab.

    Hopefully go well with my Mission m30s :D
     
  23. KH0UJ

    KH0UJ New Member

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    I have one tip also in building enclosure for subs:) the idea is to fool human`s hearing ability with a massive harmonic frequency generated by the enclosure, that`s why you wonder why some sound boxes sound so powerful than the others, the 12"X12"X12" is just fine, but if you wanna design it to have a massive harmonic frequency for me 12"X12"X40" and make a ported tube pipe at the back of the enclosure, mine is 10"X10"X20"

    here`s the pic of my modified sub:laugh: right now im living on a company barracks, my room`s ugly bro:eek:

    [​IMG]
     
  24. selway89

    selway89

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    Looks rather beefy! I'll stick to the 12x12x12 for now as a test, and see how it goes, plus space will be abit tight when I go back to uni in sept. But I'll make it an on-going project (like most things) :p
     
  25. KH0UJ

    KH0UJ New Member

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    I have an experience before on small enclosure subs and im not satified with the amount of intensity to think its a 15"inch Kicker 800W capacity:eek: after I made an enclosure by myself (18"X18"X35") ported 3" pipe at the back 33 HZ, the enclosure belongs to my co-worker and he`s shocked with the intensity:eek: after I installed back to his car:laugh: it is space consuming but he`s satisfied with the audio bass intensity, it`s my part time before way back on my college days bro and i made some money out of it to support my college course:laugh: well:ohwell: those were the days:laugh: here`s the picture of his junked enclosure, sorry for the mess but it did its purpose:laugh:

    [​IMG]

    here is the link on ebay

    http://cgi.ebay.com/NEW-KICKER-07VCVR122-SINGLE-15"-800W-WOOFER_W0QQitemZ280361501516QQcmdZViewItem
     

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