Amplifier rating Vs Speaker rating

[CaAT]

Hi all,

First up wish you all a very happy Diwali.

I have a query regarding Amplifier wattage and speaker wattage.

My question is, is there any thumb rule in the selecting amplifier wattage w.r.t. speaker wattage?

For eg, if I use a 75 Watts amplifier, will it sound good on a 70/75 watts speaker or a higher wattage speaker (say 120 watts), assuming other things unchanged?

The reason why I am asking this is that the Blaupunkt dealer in Pune has told me that the speaker ratings should be preferrably 20% higher than the amplifier rating. I am not sure about this.

Your thoughts?

Mods, sorry if this has been discussed before. I could not find any post on this subject.

TIA

[rocksterraghu]

All I know is that it is enough to keep them close - unless you want to pump the hell out of them. A little higher rated amplifier over speaker is fine, but I don't know about this 20% funda.

[low_bass_makker]

I would consider the reverse a 80 watts speaker connected to a 100 watts amp as the amp if rated at 100 watts will play clean at 80 watts and without any clipping.

[panky12345]

idea is to feed the driver atleast 70-75% of its RMS wattage to make it run OK, but overpowering it to certain extent in controlled way would give more headroom.

[Autophile]

Originally Posted by panky12345

idea is to feed the driver atleast 70-75% of its RMS wattage to make it run OK, but overpowering it to certain extent in controlled way would give more headroom.

Headroom is a term associated with the amplifiers not the speakers.

How can you overpower a speaker in a controlled manner?

[gunbir]

Originally Posted by CaAT

My question is, is there any thumb rule in the selecting amplifier wattage w.r.t. speaker wattage?

For eg, if I use a 75 Watts amplifier, will it sound good on a 70/75 watts speaker or a higher wattage speaker (say 120 watts), assuming other things unchanged?

The reason why I am asking this is that the Blaupunkt dealer in Pune has told me that the speaker ratings should be preferrably 20% higher than the amplifier rating. I am not sure about this.

CaAT, Happy Diwali to you too!

There is no simple answer to this. Some manufacturers underrate their speakers, some overrate. Some amps are underrated, most overrated. Then some speakers are more power hungry than others, while others need less power to get just as loud.

Also, keep in mind that music is dynamic, not static like a tone. It has dips and peaks and the demand on the amp is variating. Your speakers also get power in bursts, depends on the kind of music you listen to. A quality speaker that is rated for 100w RMS can take more power on music. Its nice to have a more powerful amp as there are times when a passage in your music may demand more power for a few seconds to deliver the dynamics the music demands.

End of the day, the simple answer is that if you set your gains right and theres no clipping, you can get away with even more than twice the rated power of the speaker. But you have to know your equipment and treat it with respect. So 20-25% more power is usually not an issue if the speaker is rated properly.

[panky12345]

Originally Posted by Autophile

Headroom is a term associated with the amplifiers not the speakers.

How can you overpower a speaker in a controlled manner?

arre JB bhai, what i exactly meant was speaker would play cleaner with less effort - (hence the "headroom") if the gains, BB and other settings are set properly on the amp considering the speaker in question. (hence the controlled way).

[low_bass_makker]

Originally Posted by Autophile

Headroom is a term associated with the amplifiers not the speakers.

I dont agree.

Headroom - Wikipedia, the free encyclopedia

[panky12345]

Thanks LBM..............

[jerish666]

I have question.I have Alpine R series compos 4 pairs front and rear driving the a 4 channel blaupunkt 440watts amp.But when i increase the volume speakers are jarring .Alpine R series compos is 70watt.Why it is like that?Can anyone help me?

[Autophile]

LBM,

Headroom is provided by the amplifier not by the speaker. So called speaker headroom is heaviliy dependent on the amplifier it is partnered with and bandwidth.

Without getting into bookish arguement let me tell you that a speaker will stay clean till the time it is not reached to its motor limits. A crappy 50 Watts amplifier can drive a speaker to its mechanical limits where as same speaker will play clean on a well designed 100Watts amplifier.

Same way as advanced transmission and differential is useless without a powerful engine.

Panky, you forgot the most important controlling factor - crossovers.

Also any set of drivers will play much cleaner on a powerful amplifier in an active setup than passive because of the limitation of passive network components. Power handling is also highly dependent on the crossover slopes.

[Torqy]

Originally Posted by CaAT

The reason why I am asking this is that the Blaupunkt dealer in Pune has told me that the speaker ratings should be preferrably 20% higher than the amplifier rating.
TIA

20% is just a safe margin. It's like marking the REDLINE at a LESSER rpm than the ACTUAL LIMIT.


Basically, it's to make sure that the speaker is able to handle whatever the amp throws at it. Hence a rating greater than the maximum rating for the amplifier.

-- Torqy

[jerish666]

I have question.I have Alpine R series compos 4 pairs front and rear driving the a 4 channel blaupunkt 440watts amp.But when i increase the volume speakers are jarring .Alpine R series compos is 70watt.Why it is like that?Can anyone help me?

[Autophile]

What is the model no. of your Blaupunkt amplifier. Using appropriate HPF on HU / amplifier should help. If the jarring comes from the door panels then deaden them using damping material.

[montyguru]

Originally Posted by low_bass_makker

I would consider the reverse a 80 watts speaker connected to a 100 watts amp as the amp if rated at 100 watts will play clean at 80 watts and without any clipping.

that's right.


however, in most cases installers consider the fact that young guys wanting to show off their system would crank up the volume to the full... and if you do that, without knowing where to stop, God save the speakers. therefore a safer way is to have a higher rating speaker and a 20% lower rated amp, just like the dealer suggested. you may lose speaker potential by some margin... but then, atleast you won't go back to the dealer with a sub gone "kaput". in reality, unless you test... you wouldn't know, cause speakers react differently to different amps. it's all a mix n match and try n test funda. and ratings themselves have no parameters. ID subs, for example do not follow a sinewave, they follow a squarewave... and Polk doesn't have RMS, they have a thermal rating. hee hee hee hee.