So i've just received my new speakers from the US and amplifier (which is freaking huge!).

One thing i've noticed though, the speakers are 3-ohm, the amplifer mentions it can do 8~2 ohm stable, and gives power outputs for 8,4 and 2 ohm loads. Does this mean it will happily do 3ohm? Is it just a range for impediance? I'm assuming if this is the case, the power rating at 3 ohm will be approximately halfway between the 2 and 4 ohm rating?

Any help on this would be awesome.

Should work fine. Impedence on the speaker is a joke, any way, its DC measured while the actual input is a complex mix of high frequency AC waveforms called music. lol Power rating likewise is a very fuzzy number. If the speakers sound good, then its set up right, simple as that.

Yep no problem running 3 ohms. The amp says it can run between 2 and 8 ohm speaker loads, so as 3 is inbetween 2 & 8, it's all good.

And yep, power will be somwhere between 2 & 4 Ohm ratings (might not be right in the middle of the 2, but close enough)

Like I said, power ratings are so fuzzy that you can best ignore them. As long as its loud and clear without distortion you are good to go.

Yea :) all good - I been running 3 OHM speakers on a 4ohm stable amp for a while now - (RF-60C splits with Clarion 180WRMS x 2 4OHM amp)

refering to Madmax's comment that "impedance is a joke" - in the nicest way possible that comment is a joke. If your speaker impedance is too low for your amp - your amp will over work and you could end up frying it pretty early - its VERY important that you choose the RIGHT impedance amplifier rating with speaker impedance rating - it is even more important than wattage rating (only RMS watts really matter - P.M.P.O and other ridiculous ratings are a true joke) but you can compromise power - i.e. amp 500Wrms speakers are 650wrms - you can still power them fine - you just will stress out your amp if you put it up all the way; otherwise you'll only be able to hear max 500wrms of music power - so under driving abit is ok, over driving obviously isnt. But with Impedance - regardless of wattage unless ur gona sit there and do the caculations; you could significantly overdrive your amp without even knowing it, so :) stick in the right zones.

:) as Oggy said your amp is fine :)

Ok Cheers guys, now i'm abit worried my amp is too powerful lol, amp is 4x 190wrms @ 2ohm, 4x 120wrms @ 4 ohm, so roughly 150wrms @ 3ohm, rear speakers are 130wrms, but fronts are only 90wrms. Will have to detune the amp a fair abit I think, at least it gives me plenty of head room on the amp like you said.

:) yep that amp is fine :) its good coz ur amp wuld be relaxed :) just be sure to turn the bass down if anything :) thats usualy wat ends up kiling the speakers :)

:) yep that amp is fine :) its good coz ur amp wuld be relaxed :) just be sure to turn the bass down if anything :) thats usualy wat ends up kiling the speakers :)

Yeah well these will be running HPF anyway, I have my jaycar response driving my subs :).

Thanks for the help guys, nearly had a heart attack thinking my speakers weren't compatible lol.

you can use a 1000w high quality amp to run a 500w sub but you turn your gains down and it increases the 'headroom" so your music sounds richer and you have less distortion.
if you look on www.fhrxstudios.com.au he actually explains why you more likely to fry speakers with small amps than big ones......

you can use a 1000w high quality amp to run a 500w sub but you turn your gains down and it increases the 'headroom" so your music sounds richer and you have less distortion.
if you look on www.fhrxstudios.com.au he actually explains why you more likely to fry speakers with small amps than big ones......

Yea i was just meant that if u used a bigger amp and put it up u culd damage the speakers - but yea corse having a very powerful amp wil keep it relaxed wen u turn the gains down and it wil stil be puting out heaps of power :) so its crystal :)

Well i've got the fronts in, rears wont fit until i move my amp mounting board, so they'll have to wait until the weekend. The speakers sound awesome and crystal clear, i'm just worried I don't know whether i'm giving them too much power or not. They're not distorting so i'm guessing thats a good sign so far.

Ok Cheers guys, now i'm abit worried my amp is too powerful lol, amp is 4x 190wrms @ 2ohm, 4x 120wrms @ 4 ohm, so roughly 150wrms @ 3ohm, rear speakers are 130wrms, but fronts are only 90wrms. Will have to detune the amp a fair abit I think, at least it gives me plenty of head room on the amp like you said.


100 amps at 12v ? You must be running a seperate alternator?...lol

480W RMS at 4OHM isnt 100AMp its about 40amp. - a efficent amplifier makes 500WRMS at 4OHM using 40amps :) :)

BUT if you go into the 1000W RMS region all up - you wil prb need a Capacitor or Capcell - I upgraded the wire from the alternator to a 220AMP one - i know that it only produced 108AMP but they standard wire used only takes about that - so when you are using it at its full capacity it heats up alot and that increases resistance in the cable and you end up actualy geting around 90amps :) so might wana give that a try - upgrading alternator costs a fair bit. Mine has gone 2 times, i had a 2Farad capacitor back then, now i have the 6 farad one, no prbs :)

480W RMS at 4OHM isnt 100AMp its about 40amp. - a efficent amplifier makes 500WRMS at 4OHM using 40amps :) :)

BUT if you go into the 1000W RMS region all up - you wil prb need a Capacitor or Capcell - I upgraded the wire from the alternator to a 220AMP one - i know that it only produced 108AMP but they standard wire used only takes about that - so when you are using it at its full capacity it heats up alot and that increases resistance in the cable and you end up actualy geting around 90amps :) so might wana give that a try - upgrading alternator costs a fair bit. Mine has gone 2 times, i had a 2Farad capacitor back then, now i have the 6 farad one, no prbs :)


I assumed 4x190w plus 4x120w coming to 1240 watts RMS...lol

oh no no he was sayn the ratings at 4ohm and 2ohm :)

lol yeah, although I will be running subs as well at about 300wrms each, so in total could be close to 1000wrms, do I need to upgrade any of the electrical system to handle? My cabling should be fine from the battery to the amps themselves, moreso thinking about the battery terminals/alternator.

Then again I doubt i'll be running the whole system at 1000wrms at any given time, that would be stupid loud.

lol yeah, although I will be running subs as well at about 300wrms each, so in total could be close to 1000wrms, do I need to upgrade any of the electrical system to handle? My cabling should be fine from the battery to the amps themselves, moreso thinking about the battery terminals/alternator.

Then again I doubt i'll be running the whole system at 1000wrms at any given time, that would be stupid loud.


The first time you have the volume up full throttle and turn the ignition switch will be the last time your eardrums ever hear anything ever again....lol

Just to comment on one thing on this thread - the most common cause of damaged speakers is not from a powerful amplifier sending in more watts than can be handled, but more often from a lower power amplifier being turned up too high, clipping the signal and spiking thousands of watts of noise into the speaker. The speaker overheats from this and melts a voice coil or similar.
This is most easily done by turning the equaliser (bass/treble) up on the headunit too high which introduces noise and then turning the gains up on the amp which amplifies the noise and then turning the volume knob up and all the noise gets clipped by the amp.

OK, running thousands of Watts into a little speaker will melt things too, but 150W RMS into a 90W RMS speaker will probably handle full volume reasonably well. (But I'm not guaranteeing this!).

Like others have said, I wouldn't worry about the amp being more powerful than the speakers Leigh, thats how you want it to be.

To save concern of damage, turn the volume right up on your head unit with the gains on their minimum setting, playback a fairly demanding song of your genre and slowly increase the gains until the speakers begin to distort, and roll it back a notch. Obviously this is only a guide and you still need to pay attention to distortion at high volumes when listening (to avoid it), but its the easiest way to make sure your speakers are safe.

Also when you adjust the gains, it shouldn't be set higher than the Pre-Out voltage of your head unit, if it is something isn't right. (Eg. Head unit pre-out = 5v, Amp range 8v - 0.2v, gain should be sitting somewhere between 8v and 5v.)

Adjusting to the head units max volume on a high output recording isnt really desirable.

1. Some head units will produce a clipped signal at maximum level
2. As soon as you get a soft recording, you will be quite irritated when you cant turn it up to a reasonable level

Stock power system will cope fine with a 1kW sound system, especially given that a large portion of that is going to your speakers and will never see its rated power at a continuous rate. Grounds and power cable thickness are another matter but 4 gauge will accommodate it fine, and if you do experience any irritating dimming or anything, then you can look into the upgraded grounds and whatnot.

If you don't have much experience in level setting, I would suggest giving it a go yourself, then going to a car audio store with an oscolliscope and getting them to scope set the amps to the chosen volume level of your head unit. This will give you a good idea of how far off you were with your tuning and a bit of understanding.

You're not wrong woob, I chucked in a cd today and even at max volume, it wasn't loud at all, I dare say the gains could be upped a little bit as I am getting clean sound on max with a good song anyway, and just need to be mindful about turning it up too loud.

One big thing i've noticed though, you can tell the difference between a 128kbps mp3 and an original cd, the sound quality difference is very noticable.

Agree on audio quality. I had a friend who would delete any MP3 if it was coded less than 320kbps.
Personally, I'm happy to listen to 128, but 196 is noticeably better and I'd use that as a personal minimum recording bit rate.
I wonder what the standard bit rate is from CD? At a guess, I think it's about 1200kbps, but is uncompressed. (guess is based on CD of 1x speed = 150kBytes/s, so multiply by 8 = 1200kbits/s)

Bit rate from a CD would be similar to a WAV file, i.e. around 1.4mbps

I have to agree about what you guys have just been saying about the comparison between a CD and poorer quality files, it is very convenient for me to stream music from my phone via BlueTooth but if I have a copy of the album on CD then I prefer to play that, resorting to using the phone for convenience purposes or for things like mixtapes.