speakers / hollow sound in van

Discussion in 'Video Streaming Boxes & Services' started by carpetpaul, Apr 26, 2005.

  1. carpetpaul

    carpetpaul
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    Hi, I've got an Astravan which although was fine with just my front speakers in, ended up sounding very hollow and strange when I put some 6x9's behind the rear seats.
    I did have about 1ft square sound deadening pads fixed to each of the window blanks on the side and also along the roof, but it still sounds bad.
    I'm on with the process of removing all of the sound deadening pads. I've remade the flimsy plastic side trim out of nice thick mdf and will re-fit the speakers into those.
    Being a carpet fitter by trade I'm going to carpet the window blanks, most of the roof, the wheel arches and anything else I can get away with if it looks good
    I'm assuming that since there's such an expance of blank tinny metal that it's best giving up with the sound deadening pads since they're real expensive in any quantity and they weigh an absolute tonne in the sort of amount I'd need to do the lot.
    Carpet is really cheap, and I would immagine would make a huge difference

    Can you tell me, do you think it's worth putting some carpet on the inner part of the outside skin of bodywork, ie right behind the speaker, inside the enclosure, and also carpet the back side of the panel that contains the speaker itself, thus cutting the amount of echo behind the speaker itself. I know that this is usually done inside sub boxes, and I assume can't do any harm

    If there are any points you could raise, if you have any experience of similar problems, please post (or infact still post if you reckon my thinking is right)

    Thanks for reading this !

    Paul
     
  2. Not The Messiah

    Not The Messiah
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    Slightly different rules,but I have used Dynamat Extreme (thinner and lighter but with the same results! oh and more expensive) (It was done properly seats, carpet, dash, the lot came out) throughout the entire floorpan, and some of the walls of my RX7 (G3), this gave an overall drop of 9db (admittedly at 130mph). This however is a gain to the hifi of 9db as well drop in resonance and vibration.

    Total cost was less than 300 quid, you may not want to spend that on an astra van but spend less on the head unit and you will see the results. Get rid of 6*9s and fit components,

    I should point out that I don't plan on getting rid of my RX until I find a better car (£200K plus club excluded!)

    Buy the stuff in serious bulk (everything at once) from the right place and the price becomes quite palateable.

    Dynamay extreme
    Foam spray
    heat gun
    wallpaper roller
    spray on adhesive (when the adheshive backing just isn't enough.

    Also consider using proper acoustic foam in the gaps in the bodywork. I have never used it (or seen it) but I am lead to believe brown bread (not the edible variety) is very good!
     
  3. carpetpaul

    carpetpaul
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    I can see your point perfectly, but at the end of the day, don't forget that this is a van, it aint no flash car, I can't take it off the road cause I've got to use it every day for work, and since my £400 Kenwood head unit broke, I replaced it with a £130 Sony. I've only one amp now, and it's a £200 Caliber CA-100. I'm running just four speakers (if I put the 6 x 9's in). My front speakers ended up bieng a three way pioneer 6" set, as I couldn't tell the difference beween those and the £200 set of 5.25" Infinity components that I bought. I even disconnected the Infinity tweeters that I'd spend ages moulding into the pods that are the inner trim of the wing mirrors because they sounded so bright they hurt your ears. I tried a boxed Kenwood sub that sounded awful too. So I've cut back and am looking for a simple system that sound ok and has decent bass.
    In a sence, I totally agree that there's a correct and reccomended method for hi-fi installation, I kind of tried and it cost me loads, and I wasn't happy with the results (or maybe didn't see the results because this is a van)
    I'm gonna have a crack with the carpet, and see if it cuts the echo

    I keep wondering if I should put those 5.25" infinity woofers in the rear tailgate, do you think that 4 speakers gives a more rounded sound (when you consider it's empty in the back) or would you give it a try ? (I'd have to run them off the head unit amp)

    cheers - Paul
     
  4. Boy Lex

    Boy Lex
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    Try reversing the phase of the rear speakers - that is switch positive to negative on both of them. Vehicles are not your average acoustic environment, and it's altogether possible that you are getting a phase cancellation because of the speaker orientations. It may sound even more weird, but it may sound the dogs. I'm sure you know, but just in case: you cannot damage the speakers by doing this!
     
  5. carpetpaul

    carpetpaul
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    I'm a bit thick with this hi-fi stuff, and I did have someone else wire it in, but can you tell me, on my Kenwood units there's a slim small terminal and a larger fat one, I don't think either are marked, which is pos and which is neg ?

    Ta - Paul
     
  6. Boy Lex

    Boy Lex
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    Well typically the positive is red and the negative is black. It doesn't really matter which is which as long as you can swap them. If the wires are attached to some sort of terminal, it may be more difficult to test the theory. If it's easier, you could reverse the polarity at the amp end, just look for where the rear speaker wires are connected and swap + for -.
     

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