Date: Tue, 2 Jul 2002 11:41:54 -0500
Reply-To: Max Wellhouse <maxjoyce@IPA.NET>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Max Wellhouse <maxjoyce@IPA.NET>
Subject: Re: Stereo speaker bass upgrade
In-Reply-To: <3.0.32.20020701190000.03b2297c@bee.net>
Content-Type: text/plain; charset="us-ascii"; format=flowed
Komander: An easier way to make the point might be to say at 1 watt(RMS)
would give you 94 db at a specified distance from the speaker. The sound
pressure level(in db) would increase 3 db(barely perceptible to the human
ear) for each doubling of power to the speaker ie if 94 db is achieved
with 1 watt RMS power 1' away from the speaker,then it will take 2 watts to
get 97, 4 watts to get 100, 8 watts to get 103,16 for 106, 32 for 109, 64
for 112........ Likewise, if you move 2' away from the speaker, the sound
pressure level with 1 watt RMS will be reduced from 94 to 91 and at 4 feet
away, the spl would drop to 88db, 8 feet way 85db etc. etc.
I'm pretty sure my Rockford Fosgate 600 a4 amp has just such a voltage
booster. They advertise it at 4 channels of 75 watts RMS per channel from
roughly20hz to 20k hz and a fairly flat frequency response. That amp when
new sold for about $600 so comparing it to the Pep Boys special with
speakers included is sort of an apples & oranges thing. I don't doubt that
for the money it makes a nice contribution to the upgrade of a car sound
system. Clean source material run through clean electronics driving clean
speakers makes the band sound like they're performing in the van with you.
If Kicker claims to have set an new world record with an spl of 174 db
recently, then someone do the math on that. mean while, I'm getting back
to making the van quieter so the signal to noise ratio improves thereby
more music and less road noise.
Even with a Klipsch La Scala in the back of the van(have to raise the pop
top to get two of them in there I think) that generates on the order of 104
db @1 watt 3' from the speaker, It would take some serious heat to get to
174. I'm glad they have intruments to measure such stuff, because
listening to music at that level is kinda painful.
headed for Wisconsin in a few days.
Dimwitted Mose and Flying Squirrel
>Hello folks!
>
>Was in Pep Boys or something like that today and saw that Audiovox has
>re-released its BA-100 / BA-200 series bass speakers. This is a powered 8"
>sub in a tube. Makes a HUGE difference in sound quality. You splice this in
>to two speaker outs (preferably rear). Fits nicely behind passenger seat.
>Does a awesome job of clarifying sound. OK, for all you audio bozos it's a
>100 or 200 watt amp - for the rest of us rooted in reality is does a good
>job with 10 watts.
>OK, folks, audio reality time. These 50, 100, 200 watt amps are all bogus
>numbers - amp power means little. What matters is speaker efficiency. An 88
>db efficient speaker powered by a 10 watt amp is half as loud as a 94 db
>speaker powered by a 5 watt amp. NO WAY your stupid car stereo puts out 300
>watts. Basic OHMS law. I = V/R 12 volts, 4 ohm speaker. 12 divided by 4 is
>three. VI=watts. 3 x 12 = 36 - maximum watts EVER in to a 4 ohm speaker
>assuming a 100% efficiency. VERY FEW amps have voltage booster. So,
>assuming 20% waste in thermal heat a 25 watt amp in to 4 ohms is the max.
>Good luck getting that - a 10 watt amp is great. Speaker efficiency means
>everything. Going up 3 db in efficiency is equal to doubling your power. My
>home speakers (Altec Valencia and Altec Model 14) are powered by a 3 watt
>single ended and 12 watt triode amp respectively) will get stupidly loud on
>little to no power. My Dynaco IIIs (60 watts) through my Valencias or Model
>14s would have me arrested and evicted.
>
>So, back to the topic - an awesome upgrade in sound can be had by mounting
>one of these Audiovox powered speakers behind the pasenger seat. The four
>4" stock speakers will sound better with this bass upgrade than any
>aftermarket 4" speaker with any amp. Plus, it is easily removable if you
>need the space. A whopping $79.00 for the one I saw. Nothing comes even
>close for upgrading your sound for the $$$.
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