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Powering subwoofer - need some clarification.

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

  1. Steevo

    Steevo

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    I hate MDF on speakers, I use OSB for more strength. I have seen alot of boxes blown apart, and my 3/4" box with two 12" pioneer comp speakers is still going strong. Still oud enough to make your heart skip beats.
     
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  2. KH0UJ

    KH0UJ New Member

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    :laugh: ya MDF sucks man, for me Ived used 1/2 ordinary plywood (not the marine, its so stiff it cannot flex and very hard to tune to a lower frequency 33 HZ :( ) easier to tune cause of the flexibility, Ived put body filler on the edges of the inside of the enclosure and painted it heavily with wood enamel and used wood screws + epoxy on the joints, to have a stronger bond on the edges.
     
  3. selway89

    selway89

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    Ill be using 12mm ply. Nice and strong can be painted easily etc.
     
  4. Wile E

    Wile E Power User

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    Actually, the impedance doesn't effect the frequency response.

    As far as boxes, give me the flat response and low end extension of a sealed enclosure any day of the week. I hate the sound of ported and bandpass boxes. So muddy and dirty sounding.
     
  5. KH0UJ

    KH0UJ New Member

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    yes it does bro:), ive been rewinding a lot of 8 ohm speakers way back then to convert it to 4 ohm and 2 ohms speaker set-up, if you try to look at the frequency response on a DB meter it differs greatly, the most intensified of them all is the 1 ohm speaker coil, im talking about individual speaker itself, cause you can simply achieve lower resistances if you try to parallel them, like for example you want it to be 2 ohms impedance, just parallel the 2 pc. 4 ohms then you can have 2 ohms speaker configuration (ohm`s law), but if you try to compare it on a single 2 ohm speaker itself, it has really a great difference on the intensity and lower frequency production, a 2 ohm speaker can respond greatly even on a 10 HZ signal which the paralleled 2 pc. 4 ohm speaker cannot produce, i mean you cannot hear it anymore on the paralleled ones, it can only vibrate but the intensity is not there anymore;)


    Do an experimentation on 2 speakers with the same box and same volume level on the amp. but different resistances on the speakers itself, and try even the 60 HZ sine signal, try to swap the speakers (4 ohms and 8 ohms) with the same diameter, and hear which one is more intensified and can respond greatly on the lower frequencies;)
     
  6. selway89

    selway89

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    Im with Wile E hence going for the infinite baffle enclosure first. I think having something thats tuned to a super low frequency will be too boomy and ruin the already good sound from my Mission M30is, as I have mentioned before Im wanting to add the missing lower end that the small speakers cant easily produce. If its anything like my old Logitech Z4 sub then Ill be happy as that was a sealed enclosure sub.
     
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  7. KH0UJ

    KH0UJ New Member

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    no probs bro:cool: i just wanna make my post count rising:laugh: its almost 5 stars:rockout:
    ohh can i post one more topic?:rolleyes:
     
  8. KH0UJ

    KH0UJ New Member

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    There are two kinds of bass boomers as far as i know, the soft crawling bass boomers and the hard punching bass boomers,

    Soft crawling bass boomers usually likes hip-hop music, r&b, and disco, (mostly girls love this :laugh:), usually you can hear

    them already even on a quarter mile before they pass you, cause they`re set-up is calibrated on the lower frequencies which only a

    ported and a modified G-type can produce + higher wattage sub power amps.

    Hard punching bass boomers usually likes rock n roll, heavy metal, and classic rock, they`re set-up is tuned for clarity on the

    instruments and heart pounding bass drums, low frequency speakers usually required on this system set-ups are the higher resistance

    speaker systems, prefered enclosure designs are the W-box, sealed type and the G-box which can produce hard bass frequencies, a

    couple of mid range speakers and high frequency speakers (tweeters) is a must for this set-up.




    Some of my clients said that, hip-hop and rock n roll really dont mix too well :), for me i guess its true cause if you play soft

    crawling bass on a hard punching set-up, it really doesn`t sound so well, i mean i cant hear the low frequency responding so well

    LOL, same as the rock n roll music played on a soft crawling bass set-up, I cant hear the mid and high frequency so clearly :laugh:,

    I guess each set-ups are optimized for their own use, but for me, I like both to be honest :rolleyes:

    and one more thing, my post counts are increasing already, i just wanna make it 5 stars then im happy:rockout:
     
  9. KH0UJ

    KH0UJ New Member

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    ok im done here bro thanks for the post count :):toast::rockout:
     
  10. ste2425

    ste2425

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    just looking at your pic of the wireing you will only need one black or nuetral wire but two live wires for left and right. Thats the way a pair of in ear headphones work. dont no what it will sound like, never done it, but in theory it should work. (having two live wires to make mono i mean). (ive done the single neutral wire but ive always had to live as its been from a stereo device to a stereo device)
     
  11. selway89

    selway89

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    Yeh ste thats what I thought, but the load across my amp would be too low and burn it out, also dont think it is designed to be bridged on the outputs. Ill be doing that though from the headphone out on the Cyrus amp into a single mono phono connection and use one channel to power the 10" 8ohm sub.

    ps. love that sig :) capri mk2?


    edit:

    Also anyone got any ideas if I should have a front or downward firing cab? Will use floor spikes I would have thought to give it abit of clearance etc.
     
    Last edited: Aug 19, 2009
  12. ste2425

    ste2425

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    well ive never had much experience with home speaker setups but im doing reocrding degree at uni and the monitors we use there mainly point upwards. Ive found them better oposed to the usual forwards pointing cabs.

    and yes it is a mk2 capri :D
     
  13. Wile E

    Wile E Power User

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    Yeah, but that's only when the speaker design doesn't account for the different impedance. If you are rewinding a 8ohm speaker to be 4ohms, of course the tonal characteristics are going to change, as it was designed with 8ohms in mind, and tuned as such. But, if a speaker is designed with a 4ohm and 8ohm models from the beginning, the tonal characteristic are identical between both models, as they are both tuned to sound the same.

    When rewinding a speaker, yes, you are correct. When purchasing a model of speaker that comes in a range of impedance choices, you are not correct, as the different impedances are already accounted for in design, and the different impedance speakers are made to tonally match.

    Not only that, but you can't attribute all of the sonic changes to the speakers, some of that sonic difference will come from the different behavior of the amp at different impedances as well.

    And I have tested the difference between 2 different impedance models of the same subs directly on numerous occasions. I used tune custom stereos in cars, some for spl comp, and some for sq comp.
     
  14. KH0UJ

    KH0UJ New Member

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    I guess we have both extensive experiences about sound system set-ups:)
    maybe im wrong but i cannot find an 8 OHM speaker for sub to respond the 10 HZ-43 HZ last time:( no matter how i tuned the ported box, that`s why im just gonna utilize the owner`s current set-up than buying an expensive DVC 4 OHM speaker (2 ohms paralleled) and rewind it to a single 2 OHM speakers, maybe it depends on what`s our sub-woofer target frequency design:), cause im basing it on my custom active 4rth order low-pass filter circuit (custom cross over) which is 10 HZ to 43 HZ and i find the 2 OHMS speaker has a great response on my DB meter:)
     
  15. strick94u

    strick94u New Member

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    My buddy has his mixer and pevy amps with subs hooked up to his pc in and out f#$king awesome wish I had that setup 18 channles unreal sound out of an old p4 with 512 ram :laugh:
     
  16. Steevo

    Steevo

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    The last one I built was to fit two 5.25" basic speakers in it, and run off line power through a crossover. It was actualy really loud, and the box filtered out more, plus it provided clean punch. It would fit under the seat in a friends pickup, once he traded it off, i took it and hooked it up to my amp, and ran it four a week before I melted the voice coils and set the cones on fire.:eek:
     

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  17. Wile E

    Wile E Power User

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    Did you compare the 8 ohm models against the identical 4 ohm (or 2ohm, as the case may be) models? The 8ohm model is tuned to run at 8ohms, and sound the same as the 4 ohm models, when looking at the same model of sub. Although, true 8 Ohm subs are a rare bread nowadays. You usually can only find 4ohm DVC models anymore, short of going special order.

    I never got so far as to rewinding my own coils. I bet rewinding has a huge impact on sonic output. Something I would like to try at some point. I'm sure I can scrape up something for dirt cheap with smashed coils, and give it a go someday.

    I just have a good ear for SQ, and happen to understand how to set up a system, so got recruited for SPL stuff as well. I also ran live sound for bands, and have helped record, produce, mix and master albums.
     
  18. KH0UJ

    KH0UJ New Member

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    ya bro i was comparing them by their intensities on the low frequency sounds (10HZ to 43HZ), some of my clients last time entered

    sound off competitions, me as an installer on their set-ups I need to be there also in the event, the first month we lost only by

    two votes :cry:so im observing the judges the way they judge on the intensities cause i know our set-up have a lot more power than the

    winner on that event, ours have 6 pcs. 12" inch DVC (4ohm+4ohm) 6 pcs. 1000W double inverters on each amp. plus the mids and the

    high stuffs, my client entered the crawling bass category, so after the terrible loss :(i kept thinking of the situation why and how

    did we got beaten by only 4 pcs. 12" subs:shadedshu, the owner was so pissed:mad: (epeen thing:D) by the judges, for me as his installer i am

    humiliated too on that event:( cause im the one who plannned, tuned and made the whole set-up on his expense, the next day i decided to redesign everything (fueled by rage:banghead:) I converted and rewinded each and every speaker to

    a (2ohm+2ohm) load to maximize everything, installed a second 200 ampere alternator, one amp has 2 channels on one speaker DVC (2+2)

    last time its (4+4) on one amp, replaced the crappy 1 FARAD powercaps with a 100 ampere audio battery, one week of box tuning and testing, on the

    next month we entered again, damn im nervous on the results:eek: same category and same everything, thank god we finally won and dust

    off the one who beat us in the past competition:nutkick:, seems like the judges are measuring thier DB meters on the low frequency range,

    cause the moment I lowered the resistances and tune it on a lower frequencies on everything we have higher passmark score on the

    judges, and one thing i hate about that competition:mad:, the judges use thier own testing CD bro, so meaning we cannot use our edited

    music (bass enhanced) to ride on our sub set-up (clever freaks:shadedshu)

    So i finally concluded (just my opinion basing on my experience:laugh:) that the lower the impedance the better response on the lower frequencies, the higher impedance the better

    response on the higher frequencies.:)
     
    Last edited: Aug 20, 2009
  19. KH0UJ

    KH0UJ New Member

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    This is the block diagram as far as i can remember before:) I never took a chance to take pictures on my builds before cause im too poor to buy my own camera last time:( i can only visualize it on my mind but no proof that im the one building it, and besides its not mine also:eek: along with the trophy, the only thing they cant take from me is the knowledge and the planning that added greatly on my experience.



    [​IMG]
     
    Last edited: Aug 21, 2009
  20. Wile E

    Wile E Power User

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    That's a nice looking setup. What kind of vehicle did you stuff this all in?
     
  21. KH0UJ

    KH0UJ New Member

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    its a Honda civic 98 sir:) the two door edition, no more back seat:eek:, it looks like this:laugh:
    [​IMG]
    actually i just grabbed that picture on google:ohwell: and its a blue color, the most PITA to install on that one is the second alternator:banghead: i had to take out the main engine pulley and bring it to the machine shop to install the modified pulley just for the additional alternator:( a rock solid 3 day job just for adding the custom mountings and belt adjusters:(
     
  22. Taz100420

    Taz100420

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    For your question as to the Front or downfiring cab Selway, it really depends on what type of flooring u have. If you have carpet, use a front firing cab as the carpet dont let the sound reverberate anywhere. If you have wood floors, def. downward firing cab as the bass will sound good as it reverberates alot better.

    For my home sub setup, I use a JVC 10" sub in a front firing cab with a 240W Coustic amp(from my car) with a 400 Watt PSU from my old computer. It sounds real good as I have the gain all the way down as its way too loud in my house lol.
     
  23. selway89

    selway89

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    Ok peeps Iv built the sub :D sounds brilliant just what I wanted. However I only have it running from the left channel so any bass on the right isnt getting through.

    I were thinking of getting this http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=230366877344&fromMakeTrack=true#ht_500wt_1182 which will take high or line inputs with built in crossover and will power a mono sub from that fine. However im not sure how i would power it.... use old PC psu?

    pics shortly

    edit: bought that amp it were around a tenner so cant be bad if its not right. It has the option to bridge it so worth ago.
     
    Last edited: Aug 22, 2009
  24. KH0UJ

    KH0UJ New Member

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    That amp. is a nice one bro:) specially the price £4.00:eek:, use the low inputs on it, soundcard output is so weak to trigger the high input, use a stereo mini plug with a 2 RCA plugs at the end and set the soundcard volume to full volume then trim the output on the amp`s potentiometer, dang bro:eek: it even has a third stage low pass filter on it:twitch:


    and for the PSU, you can use an old 450W PC PSU make a switch on the green and black wires:) (7-10A current consumption on the 12 volts I think:eek:),


    KAC-626 Stereo / Mono Power Amplifier
    Bridgeable 2 or 1 channel output
    Max. power out-put (4Q) 2ch: 100W x 2, 1ch: 300W
    RMS power (4Q) 2ch: 50W x (20-20kHz, 0.08% THD); 1ch:
    150W x l (l kHz, 0.8% THD)
    2Q load capability (0.8% THD): 75W x 2
    Tri-Mode Operation
    Preout high/low pass filter (80Hz)
    3-way input mode selector (stereo / mono / L+R)
    DC-DC converter power supply <<<This is the split type power supply im talking about +12Volts is being stepped up to +26-gnd-26 (positive-ground-negative)so if you measure the +&- side of it it will result to +52 volts DC:eek: (stepped-up DC)

    Gold plated terminals

    Speaker level input

    this are the specs. :ohwell:

    make sure to use the 2 inputs when you bridge the output, otherwise it will not work (some amps will sound distorted, and some amps will have very low output sound):toast:
     
    Last edited: Aug 23, 2009
  25. selway89

    selway89

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    Yeah I know I'll be taking the headphone out from the Cyrus into the phono rca in, this means when I adjust volume on the cyrus and mission speakers the sub changes with it. Or I could wire the high output from the cyrus into the high level input on that.

    So ill put it into the bridge mode where the signal gets mixed and then put the sub across one of the speaker outputs.
     

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