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How much power?

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  • How much power?

    Is there a formula or guideline for how much amp power is good for a certain size vehicle.

    I've seen formulas to figure out everything...except how much power you should have.

    I have a pickup.

    so for example, are 2 12's too much bass...100watts or 1000watts per sub...
    15 watts or 100 per speaker, etc.

    without experimenting, is there anyway to guess what size amps, speakers subs etc to buy?

    I can't translate a 400 watt amp driving a 12" sub into how loud it would sound in a car.

    I wan't to be able to feel the bass, but not shattering windows as I drive by. Maybe pickup owners can give some suggestions.


  • #2
    i have a single cab dodge dakota with one 10" RF Punch HE2 being pushed by half of a Lanzar 800watt amp, so 400 watts to the sub and it thumps hard. i don't have a formula on figuring out what would sound good in your truck, but if you have a small or mid sized truck, i can tell you that the right 10" can do you just fine.
    "I'm going back to Cali(Iraq), Cali(Iraq), Cali(Iraq), I'm going back to Cali(Iraq), Cali(Iraq), Cali(Iraq), I know so!!!!" Now I'm here!!

    By "ToneRiddle"


    • #3

      thanks, I wasn't really looking for a "formula" per say. What you gave me was perfect.

      what about power to your speakers vs the 400 watts to the sub? There are formulas for that, but a real world answer is better than any formula.


      • #4
        I had the ability to cause significant discomfort in my 4wd (Izuzu Rodeo) using only an amp stickered as 4x50W RMS. Having said that though, it was an unregulated Soundstream Reference amp, and I think they tell fibs sometimes.

        I reserve all rights in connection to each post I author, without exception.


        • #5
          what kind of music do you listen to?
          Signature: [==||========] 20% complete


          • #6
            I listen to everything, but the majority will be hip hop, or movies on dvd


            • #7
              Lets start with the basics. If your not a crazy teen from like ny, then you don't need anything over 2000watts which will rattle every signle house you pass by.

              So, realistically, for your entire system, you really don't need more then 1000watts for everything.

              If you had to guess on a decent system. You need to go with Tweeters, Midrange, and subs. Aka, sound spectrum.

              the general rule of thumb is that the power for your highs/mids should be 1/3 the power of your subs. I don't necessarily agree with this, but use that as a guide.

              So if one of your higher tone speakers is 100 watts rms, then your sub should be around 300 watts rms.

              Now, for the other pt. Powering speakers you need to juice them otherwise they will sound like junk. Aka 100watts rms speaker, and 200 peak. thats means a 100Rms Amp will do the job, but ideally to get the most out of this speakers, you should juice it somewhere around 150Rms and even as much as 175Watts RmS for the amp. just keep in mind, you are running at the point of burning voice coils at that point.

              Well, I hope that answers some of your questions.



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              • #8
                I'm gonna have to disagree with most of these people In My eyes it's a matter of efficincy. some speakers can put out 95 db from 1 watt of power that's not some crazy 800 amp thats the full power of a walkman... Other speakers on the contrary can produce less than half that form the same amount of power. There is no formula that can work for all systems / cars because efficiency differs and acoustic's (space to fill with sound) differ. thigs you should know is.. + or - 3db is the smallest change in volume that the human ear can differinciate and that takes about twice the power to raise the volume 3db..

                as far as speaker choice think about acoutics when you chose speakers. 12" subs make deeper bass than 10" sealed boxes are crisper and quieter than ported ones etc...

                There are many tricks to effect this but physics dont change, so ask what kind of bass you want to listen to tight , loud , deep, etc and then make your choices based on that. when you pick out speakers look at their efficiency and take it down for sealed boxes and up for ported ones.. and remember that Deafness happens @ 137db or so it's really useless after that.


                • #9
                  The real deal...

                  I've been into car audio for 12 years, and built and owned many systems. I also Installed professionally for 3 years, and compete in competitions occasionaly. I'll try to lay this out for you as simply as possible, and try to dispel any myths you may of heard. First though, I need some more information about you, your musical tastes, and the particular type of pickup truck. First:
                  1- How loud to you want to be able to play the system?, not that you would actually listen to it at that wolume, but maybe occasionally. Also, the more amplifier power that is "on tap" will allow you to play it cleaner, allow you more musical headroom during transients. Just because you own a ferrari doesn't mean you drive at 200MPH all the time. I have a 1200 watt RMS system in my car with 4 amps. 700 Watts of that is devoted to mids/highs, and I usually listen to it at a reasonable level. But, it is very clean at that level, and does have the capability to rip your head off.

                  2- What kind of music do you listen to mostly?, and are you interested in a sound-quality system, or dou you just want something that just an improvement from the stock stereo? The reason I need to know this, is because certain types of music demand certain type of setups. People that listen to mostly classical, or Jazz, would probably benefit from a system with a single 8" or 10" subwoofer in a sealed enclosure for tight, detailed bass, where someone who listens to bass music, rap, or hip-hop would probably benefit from a larger subwoofer setup (multiple 12"s, pair of 15"s) in a ported enclosure for strong low-end bass extension.

                  3- What kind of truck do you have? This is asked purely to find out how much room you have for equipment, subwoofers, etc. If you wanted a system set-up for really loud bass, but had only a standard cab pickup, you are only going to have room for a pair of 10"s at the most, and definately no room for the pair of 15"s that you might want. (without serious modifications to the vehicle of course.)

                  3- How much money will you budget for the entire system? Do you have any equipment that you already own, and want to use? Do you have any reservations about buying used equipment? If you look at my system, all my amplifiers were bought used through Ebay, and one of them I already owned. If you buy used equipment, get good name-brand stuff. Do you want all new equipment?

                  Originally posted by daman10958
                  12" subs make deeper bass than 10"
                  This is not really true, but I understand what you are getting at. Any speaker, from a 1" headphone speaker, to a 18" subwoofer can produce the same tones from 100Hz down (Bass tones) because their diaphrams can move at the same frequencies. The phenomenon you are describing is just pure loudness. The reason a 18" speaker "makes deeper bass" than a 1" headphone speaker, or an 8" or 10" is because it's cone moves more air, and so gives more of a "punch in the chest" sensation. A system with 24 10" woofers will "hit harder" than a system with 4 18"s, purely because the system with 10" is able to move more air.

                  Finally, I really suggest you visit a local car audio shop, and have them demo some equipment for you using some CD's that you know. Have them demo vehicles for you, not a wall display, because the acoustics of a room are radically diffrent than that of a car.

                  Asus P5N73-AN Mobo/Celeron E1400 2Ghz Dual Core CPU/2Gb GEIL PC3200/120GB HDD/DSATX PS/8" Phylon TS


                  • #10
                    The clue is area

                    Nice guessing, but unfortunately you are wrong. If you do the maths you will see that the 4 x 18" in your example results in a much larger total area than your 24 x 10" and as a result the big woofers will be able to move more air than the small ones. (A=Pi*r^2)
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                    • #11
                      ... but I still LOVE the looks of your car!
                      EPIA CL-6000E mobo powered by 12V 55W PSU
                      Creative Audigy 2 NX
                      Samsung 152V 15" LCD panel (VGA, 1024x768)


                      • #12
                        Originally posted by bsc
                        Nice guessing, but unfortunately you are wrong. If you do the maths you will see that the 4 x 18" in your example results in a much larger total area than your 24 x 10" and as a result the big woofers will be able to move more air than the small ones. (A=Pi*r^2)
                        Okay, Okay.. I just threw the 24 number out there, but the point I was trying to make was that a larger woofer doesn't play any lower than a smaller one. a 10" woofer can play 20hz just as an 18" can, the loudness is derived from the amount of air displaced by the cone(s).

                        Asus P5N73-AN Mobo/Celeron E1400 2Ghz Dual Core CPU/2Gb GEIL PC3200/120GB HDD/DSATX PS/8" Phylon TS


                        • #13

                          1. Louder than a factory stereo, so you can really feel it, but not too loud where you can't hear someone shouting at you from the passanger seat.

                          2. I listen to everything, depending on who's in the car with me, but 98% of the time, it will be hip hop/rap or dvd movies.

                          3. El camino, but technically it is a pick-up.

                          4. Give or take $1000-1200, on the audio components. Carputer is seperate. Don't mind buying used, but new would be better. I don't own any gear yet.



                          • #14
                            Since you listen to Hip-Hop, I would definetly look into at least a pair of 10"s or maybe 12"s. You have the room back behind the seats for them and then some. To power them, I would suggest an amplifier capable of delivering 500 watts RMS to the pair of subs at the minimum. Find a mono subwoofer amp capable of driving a 2 Ohm load, then paralell both subs into it. my personal choices on subs:
                            Elemental Designs 11Kv.2 12" subwoofers:

                            ED makes some really awesome subs. They are just rolling out a new design, and these bad boys can be had for a pre-order price of $80 each. I have the older version of this subwoofer that has the flat cone, and it's taking 500WRMS without a problem.
                            subwoofer Amp:
                            Rockford fosgate Punch P6001bd

                            Or, the Kicker KX600.1

                            Either can be had for around $500.

                            Next, a 125 watt per channel amp, 2-channel amp for your mids/highs:

                            Rockford Fosgate Punch P5002 ($300)

                            or, the Kicker KX450.2 ($400)

                            Also, a good set of 6.5” component speakers:

                            CDT Audio CL-61 ($250)

                            A decent head unit:

                            Kenwood KDC-MP822 CD/MP3 Receiver ($275)

                            And wiring:

                            KnuKonceptz 4 Gauge 4 Channel Amplifier Installation Kit ($30.00)

                            And Miscellaneous installation materials: ($100)

                            TOTAL: $1500.00

                            The RMS power you should feed the subs is around 600 Watts RMS, For 6.5” component set, feed 100-150 watts to each door. That’s a total of 800 watts RMS. A nice system that is definitely not stock, can get loud when needed, and has enough power to sound clean without distortion. I hope I gave you the info you were looking for. Good luck.

                            Asus P5N73-AN Mobo/Celeron E1400 2Ghz Dual Core CPU/2Gb GEIL PC3200/120GB HDD/DSATX PS/8" Phylon TS


                            • #15
                              OH MY GOD!!

                              I just expected a simple explanation of wattage per channel or something like that. I did not expect the thorough well thought out itemized description you gave me.

                              Thank you for all of that. this post will probably be used from now on as a shopping list for the hundreds of newbies that pass through here.

                              thanks again