DVC Subwoofers

Discussion in 'The Projects Forum' started by jeka616, Jan 21, 2010.

  1. jeka616

    Thread Starter Active Member

    Jan 14, 2009
    121
    1
    Hi

    Planning to purchase Dual Voice Coil Subwoofer, Pioneer. I want to hook it up to 70+70 watt stereo TDA7294 chip self made car amp. My amp runs ok with lots of subs.

    Just curious, will it be still ok to hook up DVC subwoofer, and get it working ok?


    THanks
     
  2. Audioguru

    New Member

    Dec 20, 2007
    9,411
    896
    A TDA7294 IC produces 70W into 8 ohms when its supply is plus and minus 35V.
    It produces 70W into 4 ohms when its supply is plus and minus 27V and then it gets very hot.

    If each voice coil of the sub is 4 ohms then your amp ICs will get very hot.
     
  3. BMorse

    Senior Member

    Sep 26, 2009
    2,675
    234

    If the op wires the dual voice coils together, the resistance will be down to 2 ohms..... could possibly burn up the TDA ic :eek:......
     
  4. Audioguru

    New Member

    Dec 20, 2007
    9,411
    896
    Each voice coil has its own amplifier channel from the stereo amplifier.
    We don't know if each voice coil is 8 ohms or 4 ohms.
     
  5. BMorse

    Senior Member

    Sep 26, 2009
    2,675
    234
    In my experience, car audio speakers/ woofers are normally 4 or 2 ohms.... house speakers are normally 8 ohms, PA speakers can be 8 or 16 ohms... etc....

    In most Automobile Audio setups, you wire the DVC's in parallel so 4 ohms will be 2 ohms, and then each woofer will be connected to 1 channel on the amp, since most "better" amps usually only have 1 or 2 (bridgeable) channels.

    Here is my truck subs, 1600 watts, 4 ohm DVC's wired in parallel down to 2 ohms, driven by a 2 channel 2600 watt amplifier.... (BTW, I do custom audio and mobile computer systems also.....)

    [​IMG]
     
  6. Audioguru

    New Member

    Dec 20, 2007
    9,411
    896
    He is going to use the dual voice coil sub-woofer with his stereo TDA7294 IC amplifiers.
    The amplfiers will melt if they try to drive 2 ohms and I don't think he will parallel them.
     
  7. jeka616

    Thread Starter Active Member

    Jan 14, 2009
    121
    1
    Audiguru,
    You are right, I'm planning to use each voice coil on each channel of TDA7294.

    I've been running this amp on 4 ohms, 2 subs per channel , with +/- 35v, and usually get ~95W @ ~5-7% distortion. Yes, the heatsinks get hot, but I have a mini coolers, so TDA chips run ok. I've been running this amp on my previous cars for 3+ years now.

    The reason I asked is here:

    I think I saw on market DVC Pioneer with 4ohms each. So, in theory, I should be able to drive with same amp. The question is, what will be the effect? Will there be an interferance with each channels bass production, or it will act in series per channel, producing clear bass from each channel?

    If this is not going to work, I'll just buy 2 subs, and make large box...all I want to do is save space in the back of my SUV, but still have good bass sound..

    Thanks
     
  8. Audioguru

    New Member

    Dec 20, 2007
    9,411
    896
    Deep bass is usually mono, not stereo so each voice coil will be driven the same at the same time.
    Will the Pioneer sub-woofer survive 190W?
     
  9. jeka616

    Thread Starter Active Member

    Jan 14, 2009
    121
    1
    It states 1400W peak (which is bull s.) and 400W continious power (which is still a bit bull s.). I've got kenwood subs at home, for self made home theatre PA, i'm driving them with stk4048 hybrid chip, ~200w per channel. it states on kenwood 175W, and these have been working at home for 2+ years now. Comparing the magnet size and gauge wire of pioneer and kenwood, pioneer should be ok for 1/2 rated power.


    It will be interesting to see the results, as I've never hooked up DVC subs this way. We'll see


    Thanks all for contributions.
     
  10. Audioguru

    New Member

    Dec 20, 2007
    9,411
    896
    A 60 Watts car speaker is advertised as 600W. 600W is 600 Whats.
     
  11. jeka616

    Thread Starter Active Member

    Jan 14, 2009
    121
    1
    So, here are the results)

    I got Pioneer DVC sub, 4ohms each coil. Hooked up to stereo amp. It is functioning ok, there is no interferance with bass production. Couple of issues are below:

    1: car stereo does not have an output directly for subwoofer output, so I had to "steal" 2 wires from my back door speakers. not ideal situation..

    2. Need to wire the amp directly from battery.. I just hooked up to auxilary power socket in the back, which is 120W only. so a bit power is sacrificed.

    I'm looking for a good car stereo system, Touch Screen monitor probably is better, with auxilary subw. output etc. Any suggestions?

    p.s. here are couple pictures )) finished 10pm yesterday, there is still a bit work to be completed.
     
  12. Audioguru

    New Member

    Dec 20, 2007
    9,411
    896
    The enclosure looks too small for the driver. Does it produce deep bass?
     
  13. jeka616

    Thread Starter Active Member

    Jan 14, 2009
    121
    1
    It does look small, indeed. However, my idea was to make it taper shape ( to reduce space usage, it perfectly fits with inclined back seat), and the volume is ~49liters (~1.7cu ft), as per recommended by the manufacturer. The size is : 38 (base of taper) x 10 (top of taper) x 50 (lenght) x 40 (height of taper). The production is deep enough.

    The amp is too weak for the sub, obviously. I'm waiting to get a proper amp, so can drive the sub. But, it does what it should do, and I'm asking myself, do I really need something louder? The effect is there anyways with this amp....If I do go beyond, I think I'm getting to the stage, where will buy market made ones, rather than building.

    Enough fun with messing around and building myself)
     
  14. Audioguru

    New Member

    Dec 20, 2007
    9,411
    896
    Your enclosure does not look like its volume is as much as 49 liters.
    I made a sound system for my son's car and it was powerful and had very deep bass.
    Then I bought myself a new car that came with a factory installed Pioneer sound system. Its 10" sub-woofer is in a plastic ported enclosure that fits in one rear fender so it is difficult to see its depth but it plays very deep strong bass.
     
  15. jeka616

    Thread Starter Active Member

    Jan 14, 2009
    121
    1
    Well, here are calculations. Japanise cars look so small from outside, but inside there is hell of a room))
     
  16. jeka616

    Thread Starter Active Member

    Jan 14, 2009
    121
    1
    Gents,

    as promised, here are the results of my work)

    after 2 month of work (well, actually 2-3 days if you add up all manhours I spent on it :) ), here are the results.

    I took apart the audio system of my car, inserted a pre-amp chip with all little nuts& bolts. Result: I now have auxilary output, all shielded, clear of any noise.

    I took apart my old amp (see previous pics) and re-built it into the case from burnt amplifier. I is now much nicer and cooling is great. No noise at all)

    Sound is great...you can feel the power. I've wired up the DVC sub as one channel per 4 ohm. So I have two 4 Ohm coils driving one cone.

    will add more pics of amp itself shortly.
     
  17. Audioguru

    New Member

    Dec 20, 2007
    9,411
    896
    My car came with a Pioneer upgraded sound system. Its power is a total of 288W, some speakers are 2 ohms, there are component dome tweeters at the front corners and the Pioneer 10" subwoofer in a rear fender can be felt.
    I have never played it loud enough for the amplifiers to clip or break the glass.
     
  18. BMorse

    Senior Member

    Sep 26, 2009
    2,675
    234

    288W, break glass?? I have 2 1600W DVC subwoofers (driven by a 2600w 2 channel amp), 2 300w 4x6" in rear cab doors, and 2 5-1/4" round 250 watts each in front doors, and 2 300w 1" neodymium tweeters in dash, rattles the heck out of my truck and flexes the body panels, but never broke glass :D... (Unless you count the time it shook my rear view mirror off and caused it to break....;))

    B. Morse
     
  19. Audioguru

    New Member

    Dec 20, 2007
    9,411
    896
    A puny little 4x6" will break into flames with an input of only 30W continuously.

    Puny little 5-1/4" speakers will smoke with 40W continuously.

    Tweeters are delicate. 1" dome tweeters are rated at only 5W continuously or only 40W for only a moment for each tsss sound occasionally.

    I think you are quoting advertised Whats, not Watts.
     
    Last edited: Apr 1, 2010
  20. BMorse

    Senior Member

    Sep 26, 2009
    2,675
    234