Amps - how much power do i need?

[TG 1985]

i just got myself some kenwood 3way 7x10's dirt cheap, they say 280w peak power, and are 4 ohm. now, i'd just like to know how much power i should plug through them, myself im thinking about 100w to 200w, because i also run 4 2way 6 incers, max power on em is 140w, there's one in each door, and they run off a a pioneer mosfet 50wx4 deck, and sound fine. but some ppl told me to run 300w through each speaker, the 7x10s that is, and that an amp to run them will set me back $300-$500.

is this true, cos i remember an 800w audioline amps going for a bit under $200. i know they are shit, but i'm not after show quality sound. if any1 has an amp for sale, or can give me any suggestions on how much power i should plug through em, hit reply, and type away.

oh, and i am in melbourne.

thanx again. chris.

[TG 1985]

oh, and some info on em, if any1 is curious.

7" x 10" 3-Way Speaker
Pearl Mica Injection-molded P.P. Cone Woofer (Blue)
3-Way 3-Speaker
Peak Power 280W
Rated Power 70W
70 mm PI Film Cone Midrange
25 mm PPTA Film Balanced Dome Tweeter
Magnet Weight 510g (18 oz)
Integrated Multiple Component Crossover Network for Clear and Natural Sound
Specifications:
Sensitivity: 93dB/Wm
Frequency Response: 25 Hz - 30 kHz
Mounting Depth: 82mm
Size (WxHxD): 270 x 199 x 121mm
Weight: 2,220g

yea, 2.2kgs, theyre heavy motherfuckers.

[Kizza]

mate your speakers are rated at 70watt rms(which is a more truer rating to work with) each so if they are running from a 50w max head unit they are probly getting about 25-35watt rms from the head unit, the amp i would recomend is a small pioneer, or alpine 50wrms 2channel, they will give you the right power you need with out having to worry about blowing your speackers. last tie i checked they were on sale for $56 so there probly aroun $80not on sale, from memory they have a low pass setting which will give you more bass, which is good if u are not running a sub, your front speackers will give you enough midrange and top end to make it sound sweet
cheers
kizza

[TG 1985]

i'm running my 6 incers off the deck, and wanna plug the 7x10s in2 an amp, i haven't tried the 7x10s off the deck. i think i confused u b4. anyway, i neva knew they were so cehap, i was told anywhere from 300 to 500 to power the 2.

???

[Kizza]

well i got a 500watt max power schnieder 2channel mosfet high/lowpass bridgeable amp for 189 on special so u just gotta wait for specials, u have 2 run the deck to the amp then the amp to the 7x10s so there fore u will have amp power plus deck power,

[QldRobbo]

Do you have at least two round RCA plugs on the back of your head unit? These are called pre-amplification outputs (pre-outs). Basically, because a head unit is so small the amplifier chip within the unit isn't very good quality simply because of space limitations. These pre-outs, as the name suggests, outputs the same before it gets run through the internal amp. Therefore you want to run an external amplifier from the pre-outs to get better sound quality at higher decibels.

Amps (that I know of, some of the dodgey cheap ones might be different, I haven't looked at cheap ones personally) accept RCA input from the head unit. Not normal speaker cable. If you don't have any pre-out plugs on the back of your head unit then you *can* get a device to convert the normal speaker cables into RCA. The downside of this is that the not-so-good-quality internal amp in the head unit is being used, and then amplified again by the external amp. Basically, not as good quality.

As Kizza said, you want to work with the Watt RMS (WRMS) and not Peak or Max power/watt. You also want to match this with the amp, ie get an amp that has say 50WRMS, not 50W Max, as Kizza pretty much said himself. You just have to look out when you are buying an amp and find out its actual RMS wattage.

BTW, The difference between Max and RMS. (Correct me if I'm wrong anyone, this is just what I assume). Max power means the maximum watts that the circuitry can carry within the speaker, from the positive terminal across the voice coil and to the negative terminal. If you did happen to run this much power over it however, you would have long before reaching that blown your speaker, ripped the cone etc. RMS I'm pretty sure stands for Recommended Maximum Setting? Basically, its the watts you can run through it without damaging the speaker, and with a clean signal within the response range, without distorting.

Hehe, this is becoming a long post hey... hope this is all helping. I hope I didn't confuse you too much either.

I can't think of anything else, but if you have ANY questions at all, don't hesistate to either post here, or email me Robbo@Skins.nu

Robbo

[TG 1985]

i c now, i was being confused with the max power rating on the amp, and the rms. basically, i just need a amp, with 50w rms, or maybe a bit over. i know the rca pre-out n all that, how 2 plug it up, etc, just didn't know how much 'rms' to run through em.

chris.

[fromfy]

I have a set of 7x10's exactly what you described. I run a 300 watt per channel (75 watt rms p/c) and it does the job. But, if you do not plan on adding subs to these, then I suggest getting an amp with around 100 watts rms per channel to push em, as it will drive the speakers harder.

With the 75 watt rms per channel amp I use em through, they sound very nice, pump some nice bass for being speakers and not subs...very impressive speakers for such a low price.

Andrew.

[redgem]

ok, u can run more rms through ur speakers like andrew said, it's just up to you not to blow ur speakers up, i would go with 75w rms to exact specs, so then if u do want to turn ur head unit right up there isn't as much risk blowing ur speakers up!, but....if u want alright sound quality go with a 2x100w rms amp and run the 2 off that, more rms power running the 75wrms speakers means that the amp has more control over the movement of the cone and the sound that is produced, it will be way more accurate, but u can't put the volume all the way... u have to use ur judgement and listen for the cones over excursion, (pushing out to far) and make sure u never turn it up that much again!
amps aren't that expensive if u look around, i found a brand new blaupunkt amp for 259 which is 150w rms x2 and i'm running both channels through my pro audio Peavey sub (worth about $500) and can handle a whopping 500w RMS in pro audio application, 8 ohms and in car audio it's 4 ohms so u double that, so if i could ever afford a 1000wRMS amp i would buy it!!!
anyone got one they wanna sell me for 500? instead of 5000!

[QldRobbo]

G'day,
I don't see how running a 100WRMS amp, versus a 75WRMS amp would make any difference to you blowing up your speakers... both amp's will run higher than their RMS value if you turn the volume knob far enough, it just means past when you turn it up past 75W (or 100W) in order to copy with the extra watts it chops a bit of the signal off the top and bottom of the frequency, and distorts the signal more. Either way, you are still sending more watts to the speaker, and therefore potentially stuffing it.



Robbo