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Discussion Starter · #1 · (Edited)
I just picked up this amp for a great price, but dont know much about audio and would like to know if it will be enough to power my front and rears, NO subs at the moment.

Amp I bought is:
Alpine Electronics of America, Inc. - MRP-F250

ALPINE MRP-F250
RMS Power (at 14.4V THD+N, 20Hz-20kHz)
Per channel into 4 ohms: 40W x 4 (0.08% THD)
Per channel into 2 ohms: 50W x 4
Brigded 4 ohms: 100W x 2

Speakers are:

Front:
Phoenix gold RSD 6.5 components
6.5" COMPONENT SET RSd65cs
SPECIFICATIONS
Power Handling (Minimum RMS/Peak): 5W/120W
Impedance: 4 Ω
Frequency Response: 45Hz - 20kHz
Sensitivity: 91dB @ 2.83V/1M

Rear:
Phoenix gold Ryvel 6x9
POWE R handling (RMS /PE AK): 50W/200W
frequ ency response:
50Hz-20kHz ( V690 )
70Hz-20kHz ( V570 )
120Hz-20kHz ( V460 )
sensiti vit y 2.83V/1m:
89dB ( V690 )

Also the Deck I am using now is the Eclipse AVN2210 (the one with the tomtom in it):

Power output 50W by 4 (MAX)
RMS power output 29W by 4
Output level/Line-out impedance 5V / 55ohrm
Power supply 13.2V DC (11—16V)
Dimensions (W by H by D) 7inchby 4inch by 6-1/2inch (180 by 100 by 165mm)
Weight 5.5lbs (2.5kg)
Dimensions (PND only) (W by H by D) 4inchby 3inch by 1inch (101 by 76.1 by 23.3mm)
Weight (PND only) 0.4lbs (0.2kg)
Operating temperature range –4°F to 149°F (–20°C — 65°C)
Operating temperature range (PND only) 14°F to 131°F (–10°C — 55°C)
Suitable load impedance 4ohrm
 

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I know from others experiences that those Phoenix Gold RSD's will take a ton of power and love it. That amp will power them fine but something larger would, no doubt, be better.

Did you get the amp already or were you thinking about it? I couldn't tell from your post.
Also, how much are you getting it for?
 

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Discussion Starter · #3 ·
I know from others experiences that those Phoenix Gold RSD's will take a ton of power and love it. That amp will power them fine but something larger would, no doubt, be better.

Did you get the amp already or were you thinking about it? I couldn't tell from your post.
Also, how much are you getting it for?
Thanks for the quick reply italyn, I just picked up the alpine amp today for $84. I think its a good price but now I dont know if I need more power for the PG RSD's. The alpine amp i just got is 40 watts per channel (i think), if that is not enough how much watts do I need for those PG RSD's? 50/chennel? 75/chennel?

I am looking for clean sound and good bass.
 

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I'd ditch the rear speakers and bridge the amp to your RSDs.

Those 6x9s are just gonna shit all over your perfectly good front stage.
 

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Your new amp is not much better than your HU. Power requirement grows exponentially. Twice the power only gets you a bit louder.
 

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In theory, it is described by a logrithmn relation. You have to double the power to gain 3 db. 4X the power for 6db. Exponential. In reality, it is not exactly perfect, but you get the idea. Look it up. You'll see. It works both way thought. You need a lot of power to gain a bit of sound pressure level. You also don't lose that much decible with less power.
 

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Double the power, you'll get a 3dB increase in perceived volume.

Double the voltage, you'll get a 6dB increase in perceived volume.

I forgot the rest... fuck... I really should know this... haha...

But one thing I know from experience... when something goes up in volume by 3dB, it's twice as loud as it was before. If it goes up by 6dB... it's freaking ten times as loud.
 

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Discussion Starter · #10 ·
Double the power, you'll get a 3dB increase in perceived volume.

Double the voltage, you'll get a 6dB increase in perceived volume.

I forgot the rest... fuck... I really should know this... haha...

But one thing I know from experience... when something goes up in volume by 3dB, it's twice as loud as it was before. If it goes up by 6dB... it's freaking ten times as loud.

So with just the amp I am doubling the power of my headunit (headunit puts out about 18watts and amp 40 watts) so I should get a 3dB increase therefore it will be twice as loud as it was before? If so, that would be good enough for now.
 

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hmm, you're right. I never realised 3 db was precieved as twice as loud until now.

The human perception of, for example, sound or light, is, roughly speaking, such that a doubling of actual intensity causes perceived intensity to always increase by the same amount, irrespective of the original level. The decibel's logarithmic scale, in which a doubling of power or intensity always causes an increase of approximately 3 dB, corresponds to this perception.


Didn't think 3 db was that much from playing around with decible meter. Same with lights thought. 1 f stop = twice the light and a bit brighter.
 

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Some people will tell you that the +3dB is teice as loud thing is subjective...

But I've fucked with enough EQs at enough live venues to understand how drastic an increase 3dB is.
 

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Yes. I am not sold on twice as loud, but definitely noticibly louder. Perception is a weird thing.
 
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