From: jcg2@ns1.cc.lehigh.edu (JASON GIRARD)
Newsgroups: rec.audio.car
Subject: Re: Stereo Info.
Date: 28 Sep 92 16:54:28 GMT
Organization: Lehigh University

In article <1992Sep28.040129.19233@scott.skidmore.edu>, jreiser@scott.skidmore.e
du (jason reiser) writes:

>Are those 4 ohm or 8 ohm subs?  If they are 4 ohm you've got a
>problem.  The GM-H100 amp will provide 100 watts mono into 8 ohms, or
>160 watts into 4 ohms (per manufacturer's spec.).  Running the amp
>mono into 2 ohms is not is a really bad idea with this amp.
    The amp WAS going into 2 ohms, and for the first couple weeks, everything
    was alright.  But then one day I really cranked it, and there was no
    signal going through to the subs.  The power indicator light was on, just
    no sound.  My friend said that the cause of this was my EQ had a higher
    voltage output than the amp could handle and that the IC's blew
    (admittedly, I know very little about electronics).  Do you think he is
    right, or did whatever happened result from the 2-ohm load?
>The dimming lights are a direct cause of the amps requiring extra
>power when producing bass notes.  If you use 2 batteries, they will be
>isolated with either relays, or a battery isolator.  (Check with a
>reputible dealer).  Basically, this allows the system to run off of
>one battery and the car from the other.  However, such a set-up is
>often more of a band-aid than a real solution to the problem.  If you
>are drawing more current than the alternator can produce, the battery
>will be in a constant state of discharge (perhaps only partially).  If
>you drive your car and listen to the radio at all times, and usually
>at high volume, the audio system's battery will not have a chance to
>charge as the power is all being used for music.  But if you often
>drive without the radio, or with it at more reasonable level, this
>might be a solution to the low current problem.
>
>>     Lastly, I had my sub enclosure resting on the backseat.  I noticed that
>>     the bass inside the car was intense, but outside it wasn't very
>>     impressive.  Could this be due to the fact that the enclosure wasn't
>>     secured to a solid place?
>
>I highly doubt that the securing of the sub box will make any
>considerable difference.  The box would have to move back by some
>relevant distance (as compared with the wavelength of the note) to
>make a difference in the sound... (and I believe it would have to do
>that on every not... not possible).  At 55hz the wave is about 20 feet
>long.  As far as the music being impressive only inside the vehicle, I
>applaud you.  Do you really want to play music for the neighborhood?
>Ask them if they want you to... and if they do, get them to chip in on
>the new system.  To make the vehicle play loud enough for the
>neighbors to complain takes power and a box that is optimized to play
>higher bass notes.  If you built your box to spec, you might as well
>just throw it away right now.  ;-)  Come on, you paid for it for
>yourself, not for your buddies to flip quarters on the roof.  (The
>same thing for people whose friends complain that the system sounds
>bad when sitting in the back seat.  I would gladly design a system
>that sounded good in the front and back, if my passengers would just
>chip in the difference.)
>
>Jason, I am not really sure what you want to know.  Pounding systems
>can be accomplished in a number of ways.  What kind of car do you have
>and specifically, what is the problem with the system you have?  Let
>us know, OK?
>
    I have an '86 Olds cutlass ciera (it's my mom's).  My main question is
    about the subs.  I need all the seating area, so I want to put the sub box
    in the trunk.  I did this with my old box and the seat wouldn't let the
    bass through.  How much padding should I remove from the seatback?
    (there's a rubbery material, then about 4 inches of foam).  i want to get
    better subs and a better amp to drive them.  The trunk is about 16 inches
    high, so I think I could fit a sub box for two 12's right behind the seat.
    What I need advice on is what subs would you recommend that aren't
    overoriced?  And what would be a decent amp to power them? (I'm looking to
    send about 200 watts to each sub, maximum.
    Also, you mentioned building a box that is tuned to higher bass
    frequencies.  Could you give me any suggestions as to how to go about
    building a box of this type?
    A friend of mine bought a pair of G&S pro 8's and the shop told him he'd
    get a +6 dB boost if he didn't use a divider in the ported box.  Should I
    or shouldn't I use a divider?
        -sorry if I aeemed too general before. Thanx for your help.
                                                        -Jason (G.)