RMS or PMPO and how much is reasonable?

[waynne]

PMPO peak music power output is a really meaningless measure of a speakers output RMS Root Means Square is far more accurate and meaningfull. You need to remember that a car moving on a motorway makes a lot of noise and a basic 25W RMS system is going to need to be cranked right up in order to hear it so do not measure a cars sound system while stationary - build in some extra power for when you really need it.

The question though is how much is best. Some head units kick out 50W RMS and this seems to be a good starting point. You need to remember to fit speakers that are rated higher than this otherwise they will likely distort when up to their maximum 50W. Other people go for 500W woofers and fill the boot with crossovers amps and bass boxes.

[cheryl_88]

mine is filled!! it all depends on your taste of music wayne! u want the hard bass stuf, more the beta, if not standard 6'9 will prob do the trick. and as u said, depends how u use ur car, if alot of motorway use, more of a system!

[HDi fun]

All the numbers are meaningless. True RMS is more representative than PMPO when it comes to amplification. A loudspeaker's power handling is also hard to quantify. It's far far more subjective. Most loudspeakers peak handling is basked upon the ability to not catch fire or at least overheat and thus render the voice coils open circuit.

It's also possible to find 70 watt-per-channel RMS amps that go far far louder and sweeter than other amps rated at 200 RMS WPC. There are reasons for this, it's down to circuit design, rail voltage, power supply design and a million other factors.

Your ears are the key to this - decide what pleases you and take your time. After all, it's about music, not numbers.

In general the low end stuff is demanding on output power. So you're looking for a clean frequency response over the whole power bandwidth. Unless, of course, you like the bang thud experience of a bass unit hitting the excursion limits of a poorly made and supplied power amplifier.

I quite like to hear the start and end of EVERY note, whether it's Robert Schumann, JS Bach; Eminem; Scissor Sisters; Billy Joel or Ella Fitzgerald.

I have a Clarion head in the car with 2 Harman-Kardon power amps and twelve HK speakers. Passive crossovers work fine with decent cabling. And, it's lovely. Muscular like a Shermann tank when required, refined like a silk doll. Even offers both qualities simultaneously. Cost - factory fit Peugeot option!!!

[waynne]

Sounds like a nice setup HDIfun

[p4paco]

Especially when talking bassboxes
it also depends on what type of car you have, whether its a hatchback or a saloon.

i've got 1000w RMS comming through one sealed 12" sub in my saloon, but inside the cabin its not even half a loud, because the boot is a completely sealed from the cabin in my e46 beemer.

i had a 250w RMS in a fiesta boot, and it used to make the roof flex.

When talking about a simple system without a SUB, its imprtant to note where your original speakers are and what size they are.
small speakers really struggle to produce the midbass, (the beat)
where as a 6.5" coaxial speaker supplied with 30wRMS could easily outperform a 5 and half inch, even if it had 35-40wRMS.

and also where the speakers are mounted,... the further from your head, the more power you may need.


ALSO, not many people know this, but you should upgrade the the power wire to your aftermarket headunit, to a thicker gauge item all the way to the fusebox/battery, or they will propably never reach teir stated RMS potential. when they rate the amplifier's power, they normally have the system hooked up to a power bench providing over 13.5volts constantly.
After market systems use more power then the manufacturers one.
Thinner wires drop more volts, and lower voltage means a lower volume before the amp starts to distort.
EG, You might notice a lower maximium volume without distortion when your engine is off after 10mins of high volume.
AND i know the whole world has noticed that the lights on the aftermarket system get dimmer on the beat, thisis because the beat[bass] demands more power, coz it makes the speaker cone move more.
AND that is when you reach the limitations of what the original power wire can supply [ampage].

oops, i think i may have gone off on a tangent [off topic]

Tell us what car you have, what music you listen to,and whether you jus want to hear the bass, or if you'd like to FEEL it too. then we can help you.

[waynne]

Good post p4paco and welcome to Torquecars - you seem to know your ICE

[p4paco]

cheers wayne, pleasure to be here.
i should be poppin in AT LEAST once a week.

We all move faster if we pull in the same direction.

[waynne]

Well you managed 2 days since your last post! Are you excercising self control then?

Whats your background, Where you from, What do you do n all that?

[p4paco]

Originally Posted by waynne

Well you managed 2 days since your last post! Are you excercising self control then?

Whats your background, Where you from, What do you do n all that?

Thanks for asking:

i'm 25, West-Londoner,
I studied computer networking at uni & 2learn that i hated it.
LOL i wonder how many people have done that.
Typings a lot faster now though.

i work with the Family business, (currently 3 Resturants,)
But I'm a petrol head, through and through. But i like diesel too, Cos i like the Cost efficient performace; it means i can afford more power day to day!
i've done a bit of DIY building/decorating & rennovating with the old man(Ex-British rail engineer/safety inspector),
we've covered gas/water/electric/tiling/roofing, From scratch to showroom condition.

I've also done DIY engine rebuilds & servicing with my dad and his trusty Haynes manual. So i know how an engine works. My uncle a BMW technitian/senior mechanic for over 25yrs, and he deals with fast beemers etc, he used to take m to Brands Hatch/Silverstone to watch Touring car when i was young. thats what got me hooked on things with engines that move. Not to mention my dad getting me and my brother a motorcross bike when i was 5yrs old, [which i learned to ride long before my feet reached the floor.]
Since passing my Driving test i've been to 7 Car shows, comprisng of "Edition 38"for VAG (vw audi group), & "Maxpower Live" in Birmingham, and i used to go to Car crusies a bit when i had time to doss about; "Ace Cafe",is not far from me.

After learning how to build an excellent sound system to decent budget in my fiesta, i became a bit of an audiophile, B'coz its all abot the sweet spot.

Currently,
I drive a Black 1999 e46 BMW 320D,18"bmw wheels, schnitszer suspension, Xenons, Red leather electric memory seats, etc etc, with
162,000miles on the clock. Its a high milage hero, still runnng cleanly.
my ICE [in car entertainmet] is running from a Pioneer Sat/Nat mp3/DVD toucscreen unit with G-force meters!
that leads to a vibe Mono-block CLASS D amplifier which is over 1000wRMS @1ohms resistance, leading to a budget brand "SPL" Competition level SUB with dual 2ohm voice-coils which are bridged into 1ohms to ensure my amp is able to work at its peak.

i've got a power cap and second amp fitted but i haven't got around to connecting up the wires, because i had to install them while lying upside down to fix them to the roof of the boot (solid fixed parcelshelf in saloons).

So i'm a bit of a Jack of all trades. i know something about everything.

Oh yea this part usually interests pple:
i got hit HEAD ON by a drunk driver when i was on a motorbike in Y2K,
So I Dont Codone it!
& i expect ALL of you not to condone it
He was doing 35mph and i was doing 30mh at point of impact
30+35 =65mph impact
yes it hurt, and yes bones broke, but bones do heal, so i am still walking/driving. Now that i RE-LEARNED them.

Vehicle progression>
ford seirra estate, Old Mini, Aprilla 125sr(bike), volvo850 2.5litre Auto(after bike accident,LoL), ford fiesta mk3, Golf mk4 TDPDI, Bmw e46 320D = vehicle progression

and thats pretty much all about me.
lol, just rembered U mentioned self control, Sorry, but U know how2scroll.

[waynne]

Thanks for the intro - my scroll wheel has just broken I think we have all done a course and decided it was not for us.

I did 14 years as an insurance broker before I decided it was not for me then I went freelance web designer - so I get involved in a bit of networking and I can see why you dind't get on with it too well RX,TX Rwin and all that! Its more satisfying tuning a car than a network server!