Hi... upgrading my system,

I have an older Alpine amp that's rated 4x25w at 4-ohms. I also have a
two-year-old Alpine head unit that's rated 4x40w (no ohm spec given but
probably 4 also).

Can I assume that the Alpine amp is rated "continuous" power and will be
considerably louder than the head unit's output?

I'm trying to figure out if it's worth it to install this older amp in my
truck, or buy a new 5-channel design that can power a single 10" sub?
(future purchase)

Thanks,
Jon

So far...
Alpine CDM 7857 head unit from a previous vehicle
4 Polk DX7 6x8s installed with Dynamat

I have an older Alpine amp that's rated 4x25w at 4-ohms. I also have a
two-year-old Alpine head unit that's rated 4x40w (no ohm spec given but
probably 4 also).

The amp will sound better than the onboard power.

Head units almost always give you peak or max power rating. Usually w/ amps
the rule of thumb is that peak power is double the continues or RMS power. For
some reason, on head units, the push the envelope with the specs, so that 20
watts becomes 45 watts, 22 watts becomes 50 watts etc.

Regarding your amp, the power you will get will be governed by the amp design.
Many of the Alpine amps only give you your rated power at 14.4 volts. At 12
volts the actual power falls off precipitously.

Still, the amp will give you better sound than the onboard amp.

Now - I hand you over to our next guest author who will tell you why twice as
much power doesn't make an amp twice as loud:









..
www.MAINSTREET-AUDIO.com
~ ~ ~ Where SERVICE never goes out of style ~ ~ ~

V I S I T O U R F O R U M
http://63.74.14.174/forum/phpBB2/index.php

Now - I hand you over to our next guest author who will tell you why twice
as
much power doesn't make an amp twice as loud:

And that would be because we perceive "twice as loud" to be a 10 dB
increase, whereas a doubling of power produces a 3 dB increase.

-Bill

As for the Alpine statement .... pfffftt.... liar.... they give you a birth
certificate with 12v RMS rating... plus the box and manual have bridged, 4
ohm, 1 ohm, 12v and 14.4v ratings.... and Alpine.... well... let's just say
the V12's rated at 50wRMS @ 12v into 4 ohm generally produce 70+wRMS with
those exact same settings.

I know this is a little off-topic, but hey.... I just had to!

Murray


"Quigmeister Quigolator Quiganology" wrote in
message ...
I have an older Alpine amp that's rated 4x25w at 4-ohms. I also have a
two-year-old Alpine head unit that's rated 4x40w (no ohm spec given but
probably 4 also).

The amp will sound better than the onboard power.

Head units almost always give you peak or max power rating. Usually w/
amps
the rule of thumb is that peak power is double the continues or RMS power.
For
some reason, on head units, the push the envelope with the specs, so that
20
watts becomes 45 watts, 22 watts becomes 50 watts etc.

Regarding your amp, the power you will get will be governed by the amp
design.
Many of the Alpine amps only give you your rated power at 14.4 volts. At
12
volts the actual power falls off precipitously.

Still, the amp will give you better sound than the onboard amp.

Now - I hand you over to our next guest author who will tell you why twice
as
much power doesn't make an amp twice as loud:









.
www.MAINSTREET-AUDIO.com
~ ~ ~ Where SERVICE never goes out of style ~ ~ ~

V I S I T O U R F O R U M
http://63.74.14.174/forum/phpBB2/index.php

Actually, a 3db increase is generally perceived as "twice as loud." Perhaps
you are referring to the generally accepted idea that a sound twice as loud
has had its intensity increased 10 times? Remember, the db (ok ,dB) scale
is logarithmic, not linear.

"Bill Pallies" wrote in message
om...
Now - I hand you over to our next guest author who will tell you why
twice
as
much power doesn't make an amp twice as loud:

And that would be because we perceive "twice as loud" to be a 10 dB
increase, whereas a doubling of power produces a 3 dB increase.

-Bill

Actually, a 3db increase is generally perceived as "twice as loud."


No, a 10dB increase is perceived as twice as loud. A 3dB increase is
perceived as a minor change in volume.


Perhaps
you are referring to the generally accepted idea that a sound twice as
loud
has had its intensity increased 10 times? Remember, the db (ok ,dB) scale
is logarithmic, not linear.


Ok, a doubling of power is a 3dB increase, or twice as loud. Because human
hearing is not linear we need to hear about a 10dB increase before we think
it's twice as loud.



Paul Vina

you have it wrong...
a 3db Increase is not percieved as double the volume level, it is in fact
just slightly noticable...

james w wrote:

Actually, a 3db increase is generally perceived as "twice as loud." Perhaps
you are referring to the generally accepted idea that a sound twice as loud
has had its intensity increased 10 times? Remember, the db (ok ,dB) scale
is logarithmic, not linear.

"Bill Pallies" wrote in message
om...
Now - I hand you over to our next guest author who will tell you why
twice
as
much power doesn't make an amp twice as loud:

And that would be because we perceive "twice as loud" to be a 10 dB
increase, whereas a doubling of power produces a 3 dB increase.

-Bill