ClioSport.net
Register a free account today to become a member!
Once signed in, you'll be able to participate on this site by adding your own topics and posts, as well as connect with other members through your own private inbox!
-
When you purchase through links on our site, we may earn an affiliate commission. Read more here.
RMS?
- Thread starter T_11!
- Start date
A few pointers that hopefully will allow you to decide for yourself...
1, You can't under power a speaker, lower power equals lower volume....
2, A speakers input rms is the amount of power the speaker can handle whilst playing a 0dB tone continuously for a given period of time before it reaches its mechanical or thermal limits....
3, An amplifiers output rms is what the amplifier will deliver continuously at a given power supply voltage, (usually 14.4V), playing a 0dB tone without 'clipping'....
4, You can't record music at anywhere near 0dB, in most cases you can expect upto a 50% drop in output power, so an amplifier that produces 50w rms per channel on paper will probably deliver around 25w rms per channel whilst playing music, due to the logarythmic scale used to measure sound this isn't half volume though....
5, Enclosure type & size will affect a speakers power handling & efficency, smaller sealed enclosures will increase power handling & decrease efficiency, larger ported enclosures will decrease power handling but increase efficiency....
Most importantly you should make sure your amplifier input sensitivity or gain control is set to match your head units pre-out voltage, this will guarantee there is no chance of any 'clipping'....
Clipping kills coils rather quickly....
An amplifier has two voltage rails, one is +ve voltage, the other -ve voltage....
+ve voltage pushes the cone outwards
-ve voltage pulls the cone inwards
Too little gain = lost output
Too much gain = Clipping, Extended period of time at full power, cone motionless and rapid heat build up, heard as distortion... Unhappy amp & Unhappy hot coils
Correctly set gain = Happy amp, Happy coils, full output
Hope this helps a little....
1, You can't under power a speaker, lower power equals lower volume....
2, A speakers input rms is the amount of power the speaker can handle whilst playing a 0dB tone continuously for a given period of time before it reaches its mechanical or thermal limits....
3, An amplifiers output rms is what the amplifier will deliver continuously at a given power supply voltage, (usually 14.4V), playing a 0dB tone without 'clipping'....
4, You can't record music at anywhere near 0dB, in most cases you can expect upto a 50% drop in output power, so an amplifier that produces 50w rms per channel on paper will probably deliver around 25w rms per channel whilst playing music, due to the logarythmic scale used to measure sound this isn't half volume though....
5, Enclosure type & size will affect a speakers power handling & efficency, smaller sealed enclosures will increase power handling & decrease efficiency, larger ported enclosures will decrease power handling but increase efficiency....
Most importantly you should make sure your amplifier input sensitivity or gain control is set to match your head units pre-out voltage, this will guarantee there is no chance of any 'clipping'....
Clipping kills coils rather quickly....
An amplifier has two voltage rails, one is +ve voltage, the other -ve voltage....
+ve voltage pushes the cone outwards
-ve voltage pulls the cone inwards
Too little gain = lost output
Too much gain = Clipping, Extended period of time at full power, cone motionless and rapid heat build up, heard as distortion... Unhappy amp & Unhappy hot coils
Correctly set gain = Happy amp, Happy coils, full output
Hope this helps a little....
Clio MK 4
so its better to have higher rms on the speaker than the amp?
Ph1 172 + Combo van
Aslong as your speakers are good they will take a lot more then their rated power. If you use poor quality speakers then it will not sound very good. My amp says 90w rms per channel, my speakers are only rated at 40w rms but they sound great.
I did have a pair of £30 alpine components amped with 90w rms going to them and after about an hour of playing i started to get a nasty popping sound from them:clown:
A few more answers....
When you take into account a few variables, the quoted figures become less impressive, for example;
1, Power supply resistance; You may have 14.4v at the battery terminals, but whats the reading at the amplifier terminals??? The higher the draw, (volume level), the greater the resistance, which induces further voltage drop within the amplifier....
2, Impedance rise; This is affected by a few variables such as, speaker cable resistance/length, speaker enclosure type/size, speaker voice coil temperature, (heat increases impedance)....
3, Source recording level; Already covered I believe....
I've just thought, maybe your all not like me, (I need answers supported by reasoning and full explanation), maybe you just require a simple answer, (would save all these overlong posts)....
60w rms speakers will be fine off an amplifier rated at 20w rms to 120w rms per channel as long as gains are set correctly....
With regards^^this^^....No they won't, power kills coils, power promotes over excursion, as previously stated there are variables to consider, but the above statement is fundamentally incorrect.....Power ratings vary from manufacturer to manufacturer, some speakers won't run at rated power for extended periods, (Audiobahn, In-Phase & Vibe for example), but others, (JBL, Fi, & DD for example), will....
With regards^^this^^....Correct to a certain degree, if you use good quality speakers installed badly the poor quality units will often out shine the quality ones, but again there are many variables which govern the difference between 'quality' & 'tat'....I would say it's 80% installation, 20% kit, so cheap units installed correctly will often out perform quality units simply screwed in....
With regards^^this^^....Your amp may state 90w rms per channel, but to achieve that figure it needs to be playing a source recorded at 0dB, be receiving a 14.4v power supply and be seeing the correct impedance....Unfortunately this rarely happens....
When you take into account a few variables, the quoted figures become less impressive, for example;
1, Power supply resistance; You may have 14.4v at the battery terminals, but whats the reading at the amplifier terminals??? The higher the draw, (volume level), the greater the resistance, which induces further voltage drop within the amplifier....
2, Impedance rise; This is affected by a few variables such as, speaker cable resistance/length, speaker enclosure type/size, speaker voice coil temperature, (heat increases impedance)....
3, Source recording level; Already covered I believe....
I've just thought, maybe your all not like me, (I need answers supported by reasoning and full explanation), maybe you just require a simple answer, (would save all these overlong posts)....
No, to gain full benefit from your speakers, select an amplifier that has around 50% to 100% 'headroom', it's always possible to run lower 'gain' settings to compensate if necasary....
60w rms speakers will be fine off an amplifier rated at 20w rms to 120w rms per channel as long as gains are set correctly....
I believe this poster is referring to people using low power amps, who then increase the gain settings to compensate for low output only to push the amps into 'clip', which quickly kills speakers & in some cases amps too....
Doesn't matter, as long as gain settings are correct....But, if you want higher volume then opt for a bigger amplifier.....
clio II
Its brilliant the way you give reason to all the madness, makes for interesting reading 
Ph1 172 + Combo van
+1 There is nothing i can contest about what wallop just wrote, I prefer not to go into such detail in my posts unless i have toIts brilliant the way you give reason to all the madness, makes for interesting reading
. When i say 90wrms i dont mean that as a true figure, i just mean thats what jbl rate it at. What would be the best way for getting a true figure of waht rms a speaker is getting? im intrigued.OK, once upon a time......lol, this would be a monster post...
Have a read here .....
You can't really use any formula for working it out whilst playing because a speakers impedance changes in accordance with heat generated, frequency being played etc etc.....
So even testing with dummy loads won't give an indication of true output power whilst actually driving a speaker playing music....
Have a read here .....
You can't really use any formula for working it out whilst playing because a speakers impedance changes in accordance with heat generated, frequency being played etc etc.....
So even testing with dummy loads won't give an indication of true output power whilst actually driving a speaker playing music....
