Need Help - Speaker Power Handling

by jsng Wed Oct 21, 2009 3:02 pm

Hi all ...
A quick question .. might be a dump question .. Need Help - Speaker Power Handling Icon_razz

hope u all dun mind ...

If my speaker is stating that the max power handling is 100w, Nominal impedance = 8ohm, can i use an amplifier that is having 125W per channel to drive this? Since the power delivered by the amp is higher than the power the speaker can handle, will it damage the speaker?

Thanks and hope to hear from you all ...

Regards,
JS

by **WongKN** Wed Oct 21, 2009 4:38 pm

Yes you can.

Note : as long as the question is asked honestly and genuinely, there is never a dumb question ! Need Help - Speaker Power Handling Icon_biggrin

Despite how 'good' we currently are, -all- of us will have asked that 'dumb' question before.

by jsng Wed Oct 21, 2009 4:42 pm

Thanks KN :-)

So is that saying that the statement below that i have picked from some articles are true?

"In general, the amplifier power needs to be larger than the speaker's rated
power. This is because an amplifier only delivers its rated output power with
sinewave signal, and delivers much less with a real signal with dynamics. As
ageneral guideline, it is
recommended to use an amplifier delivering 50% more power than the speaker's
average ("RMS") power. For example, for a speaker with 450W average
power, an amplifier with an output of 700W may be used. If a small amplifier is
used, sufficient level will not be reached, nor the perception that it is
attained, so the signal will tend to be clipped to compensate, thus endangering
the integrity of the speaker."

But i am still a bit confused, if the speaker can only handle up to 100w, what happen to the extra 25w that has been delivered? will it cause any damage to the speaker like generating extra heat? or ??

by **WongKN** Wed Oct 21, 2009 7:00 pm

From my angle, I see two considerations to this amp power vs speaker power matching. First is that a speaker impedance rating for e.g. is given as a single figure. But in reality it is seldom consistently that figure over the entire frequency spectrum. So a speaker is rated for 100w at 8ohms. But from (say) 30Hz to 20,000Hz, the actual impedance will and often do change drastically. So 8ohm is usually listed as 'nominal' or perhaps 'average' or 'expected'. And the actual impedance can go down to say 6ohms or up to say 10ohms (just figures to illustrate the scenario). When a speaker impedance change, so too its ability to draw power. One of the most famous speaker in history, the Apogee Scintilla had this characteristic. Apogee may rate it at some sane impedance but at certain frequencies, its impedance will go down to 0.5 ohms (or lower). This caused many amps to short-circuit and blow up (first hand witness of it happening at a dealer's place).

The 2nd issue is that the rating of an amp is in terms of RMS or root mean square. Again take it as something like an average. So 200Watts RMS. But during loud passages, how much does the speaker require and how much can the amp deliver. This is the basis for that statement that the amp should outpower the speaker.

Usually good speaker manufacturers will give you a suggested minimum power for the amp to match their speaker. E.g. Apogee Centaur Major is rated by Apogee to require an amp of 80watts.

My personal experience is that the more powerful the amp, the better the speaker dynamics and ability to reproduce life-like sound, esp music like classical symphony, or rock, or even many pop and jazz.

by ryder Wed Oct 21, 2009 8:20 pm

jsng wrote:
But i am still a bit confused, if the speaker can only handle up to 100w, what happen to the extra 25w that has been delivered? will it cause any damage to the speaker like generating extra heat? or ??

In normal listening at sensible volume levels the amplifier won't be delivering near its maximum output to the speakers. It all depends on how loud you are listening and the SPLs you are getting at a given distance from the speaker. If you are listening in nearfield at an average 75dB SPL a 100W rated amp would probably just deliver 10W of power or less to the speakers. It depends on the volume control that you are holding in your hand as the amount of power drawn from the amp to the speakers is governed by how loud you listen to the music. You won't damage the speakers if they are not overdriven. Speakers often get damaged when folks blast the music at high volume levels where the amp struggles to keep with the SPLs which in turn cause the amp to clip. That's when the maximum power required in the SPLs exceed the max power output of the amp that kills the speakers and/or the amp. When the amp is working near its maximum power output ie. at high SPLs one would be able to tell when the music starts to show signs of strain or distortion.

by mugenfoo Wed Oct 21, 2009 9:08 pm

An amp clipping by itself is not the reason why speakers get blown.

While amps are only rated to a certain "brochure" wattage. Amps by their very nature is very capable of delivering much much more power than the typical figures in the spec sheet. A NAD 3020i (for example) can easily deliver 100+Watts into the speakers .... of course the sound would have been heavily distorted due to all the clipped frequencies .. but IT CAN deliver such powers for a brief period of time. And it's this power overload that burns the woofer coils, or the Amp's output transistors (whichever goes first).

There are also plenty instances (especially among high-end folks with deep pockets and heavyweight amps) who cook and tear their speakers apart but their amps are still happily working without smoking. This is another case of speakers being over-driven physically.. and whilst the sound is just crazy loud (but doesnt sound "broken" because the signal is not clipping) and will go much louder until the very last moment before the speaker's physical failure. Usually, some audible KNOCKS of the woofers hitting the stoppers might be heard (or might not be, since its being played as extremely high levels already).

Besides, speaker manufacturers aren't also very forthright with their ratings. They almost never say that if the speaker can handle 100Watts, does it mean it can handle 100Watts RMS, across the entire audio spectrum 20Hz to 20KHz?

Often times, bookshelf speakers cannot even handle pure 50Watts of 20Hz (or they actually have a choking capacitor in the X-over circuit to kill off the low notes & subsonics) as the woofer cone would not be able to handle the physical exursions anyway without tearing apart its flexi surround.

by ryder Wed Oct 21, 2009 9:43 pm

Mugenfoo,

You mentioned amps in their nature are capable of delivering *MUCH* more power than their rated figures shown in the specifications. How much is much, and on what basis have you derived this statement apart from knowing that the NAD has output a power that is higher than its maximum output published in the specs? I guess you are referring to the peaks in the SPLs but this would relate back to the power output of amplifiers as published on paper.

Figures by manufacturers can sometimes be little inaccurate. The published power handling are recommended and often nominal figures. As for how much power a speaker cable handle, some manufacturers have quoted this in the maximum SPLs while some do not. The figures can be slightly off as well. One wouldn't know if the numbers are accurate unless the speakers are tested to their limits that may eventually cause the woofers to blow up.

by mugenfoo Wed Oct 21, 2009 10:01 pm

Well, you're right .. we NEVER know what is the maxx power @ the point of failure . Until it happens.

But no, am not referring to peaks. RMS all the way just for references' sake.

Most amps can go way beyond rated power specs. For example, a Naim Nait XS can nicely deliver 60Wrms into a 8ohm load @ say around 0.01%thd . It could also deliver 70Wrms at maybe 3%thd ? .... 100W at 15% thd (15% would sound pretty awful , clipping and all .... ).

But if the speakers are not even rated for 50Wrms, (woofer coil rating) .. then even the Naim XS playing at the ceiling of its "normal" capability" is enough to blow the speakers already. And this is before any clipping sound is audible.

Same goes for lower power amps ... if the user clips the amp .. and still continues cranking up the happy-knob, then even a 150W rated loudspeaker will be smoked becoz the amp really is outputting more than 150W of nasty sounding distorted power into the voice coils.

by mugenfoo Wed Oct 21, 2009 10:04 pm

... or if the voice coil doesn't blow .. then the amp's output stage will, most commonly due to thermal failure aka smoking tea-pot.

by ryder Wed Oct 21, 2009 10:06 pm

So you are referring to increasing power at varying speaker impedances. That clears the confusion.

by mugenfoo Wed Oct 21, 2009 10:06 pm

... or if u happen to own a Krell MRA amp, it will just trip the house's circuit breaker (or in the case of this one incident in Hong Kong, an entire apartment block's electrical supply).

That is if the speakers have not been reduced to a pile of ashes already.

by mugenfoo Wed Oct 21, 2009 10:06 pm

ryder wrote:So you are referring to increasing power at varying speaker impedances. That clears the confusion.

Nope ... lets keep speaker impedances as "constant" for the sake of this example.

by jsng Thu Oct 22, 2009 6:24 pm

So looks like the most scary thingy is when the amp is not able to deliver sufficient power to the speaker Need Help - Speaker Power Handling Icon_tongue

As compared to slightly over powered ...

But looking at so many uncertainties as the data provided by the manufacturer are not "that" detailed ... it seems hard to get a general guideline in pairing up speakers and amp, right? Need Help - Speaker Power Handling Icon_question

by mugenfoo Thu Oct 22, 2009 7:24 pm

jsng wrote:So looks like the most scary thingy is when the amp is not able to deliver sufficient power to the speaker As compared to slightly over powered ...

But
looking at so many uncertainties as the data provided by the
manufacturer are not "that" detailed ... it seems hard to get a general
guideline in pairing up speakers and amp, right?

No, the most scary thing is what the amp delivers too much power to the
speakers. It doesnt matter if the amp delivers high quality power (as
in the example of the Nait XS with 50W speakers), or if the amp
delivers highly distorted power (clipping and shit) to the speakers.

If a puny amp (like the internal amps used in Edifier-type speakers) is
used to drive a 100W rated loudspeaker, it is highly unlikely any
damage can be done to the speaker becoz the puny amp just cannot output
anything more than a couple of watts of power.

Also, the best pairing up of speakers and amp would be your own ears.
And generally, it is always better to have a more generous amp power
than what is demanded by the speakers. With the trained ear, the
symptom of insufficient power from the amp to the speakers is extremely
audible even before signals start to clip. The sound is as @WongKN
described when ample power is delivered to the speakers. You get a more life-like, more open, sound. If Not enuff power, the sound is very flat, bland, poor muddled bass, smeared highs, etc etc. Basically a big pile of shitty sound.

by **WongKN** Thu Oct 22, 2009 7:28 pm

I think there is an english proverb that says something like 'you never know until you have tried it'. This applies to hifi system matching. I have heard a system comprising the best components sound worse than another comprised of much lower priced components and my opinion was that it was all due to matching and set-up and also suitability of the system to the music being heard. There is a tendency in modern society towards a 'plug-and-play' mentality. This is often exemplified by over-reliance on reviews. If an amp is well reviewed it must be good. So too for the speaker. Therefore, the logic of PnP in HiFi goes, if I match a Stereophile Class A amp with a Stereophile Class A speaker, then the resulting pairt must surely be Stereophile class A+ ! Simple maths. Many a time it does not work out that way. Reviews are very useful when used the right way - to get an idea of the characteristic, strength and weakness of the componet, not the deciding factor for the buying decision. The only sure way is to listen to the combination of amp + speaker with the music you like and then as the song goes "listen to your heart". If you are moved by the music, then it surely can't be wrong. But if you struggle to like the music and must pretend to be bouncing along with the music just because others around you are, then something must be wrong somewhere.

by car o scope Mon Oct 26, 2009 3:18 pm

I have a chat with my friend at a kopitiam that day.
While talking about speakers, one question came to my mind. Need Help - Speaker Power Handling Icon_question

Why speakers require more wattage to drive when the impedance drops (8ohms --> 4ohms --> 2ohms --> 1ohm --〉0.5ohm)?

We assume the impedance is like resistance.
Normally, the drop of resistance means less hassle and less power to drive. However, it was the opposite, which requires more power.

I have read the water hose analogy article and get some idea.
Still, I cannot confirm whether the decrease in the impedance at certain spectrum of the frequency is actually the reduction of the limitation which allow the speakers to use more wattage. Need Help - Speaker Power Handling Icon_study

Is it that way? Anyone can provide better info? Need Help - Speaker Power Handling Icon_question

very very the confused....

by mugenfoo Mon Oct 26, 2009 4:55 pm

confusion is good. Ignorance is bliss.

Enjoy the music.

Spoiler:

by cmboy Mon Oct 26, 2009 6:27 pm

mugenfoo wrote:confusion is good. Ignorance is bliss.
Enjoy the music.

Let me add this since you like to quote quotes.
Good judgment comes from experience. Experience comes from bad judgment.

by mugenfoo Mon Oct 26, 2009 9:27 pm

cmboy wrote:
Let me add this since you like to quote quotes.
Good judgment comes from experience. Experience comes from bad judgment.

so, its ok to make bad judgements in order to gain experience... then the experience would (hopefully & eventually) help u to make good judgements ... right ?

Whatabout for those people who just "never seem to learn" no matter how many times? Razz

At the end of the day ... whatever makes u happy dude ... Even if this includes making "bad judgements" for your own amusement ... sure, why not? Need Help - Speaker Power Handling Icon_razz

Now, back to .. err, what was the topic again?

by mugenfoo Mon Oct 26, 2009 10:49 pm

cmboy wrote:
mugenfoo wrote:confusion is good. Ignorance is bliss.
Enjoy the music.
Let me add this since you like to quote quotes.
Good judgment comes from experience. Experience comes from bad judgment.

BTW, didn't borrow that line from anywhere. Just blurted it out randomly. Need Help - Speaker Power Handling Icon_king

by uncle_vic Thu Oct 29, 2009 3:14 pm

That could be the way to become a real 'hifi guru'!!!!! Need Help - Speaker Power Handling Icon_lol

unfortunately many won't share 'their mistakes' made over the years!!!
got to save some face ma!!! Need Help - Speaker Power Handling Icon_lol

by mugenfoo Thu Oct 29, 2009 5:20 pm

uncle_vic wrote:That could be the way to become a real 'hifi guru'!!!!!

unfortunately many won't share 'their mistakes' made over the years!!!
got to save some face ma!!!

OK uncle Guru .... if u care to share yours .... sure some of the regulars here are very keen to read and "learn". Can ?

Lesson no.1 : .......

by uncle_vic Fri Oct 30, 2009 9:59 am

I also want to save face ma! Need Help - Speaker Power Handling Icon_lol

like the chinese saying goes.....teach the pupil everything then the sifu will die of starvation ma!!!! Kekekeeee!!!! Need Help - Speaker Power Handling Icon_lol

Read and learn is one thing.........hands on is yet another bro!!! Need Help - Speaker Power Handling Icon_lol

Build your own speakers......
build your own everything u want in hifi if possible.....then
go and buy the stuffs u need, chance u may look for the right stuff
in the shortest time possible......mind u the requirements fit only 1 persons only......yet another person may like different stuffs.....its all comes down to preferences la......

the most interesting thing that i come across which affects everyone is the fact that different persons listen to a same setup will have very different perceptions of the setup, at times even contradictory too.......the worst case scenario will be 1 learned listener could swear that the setup sounded very very bad.....and yet another learned listener do not think it's that bad....in fact very good!!!!!! now wat gives?!!! Need Help - Speaker Power Handling Icon_lol

solve this mystery and u will be a hifi guru in the making!!! No kidding!!! Need Help - Speaker Power Handling Icon_lol

by mugenfoo Fri Oct 30, 2009 11:31 am

uncle_vic wrote:I also want to save face ma! like the chinese saying goes.....teach the pupil everything then the sifu will die of starvation ma!!!! Kekekeeee!!!!

Ok dude, it's all you guys' "face" to save .... this "face" thing is irrelevant to me & i'm not in the hi-fi industry anyways ....

What people may or may not learn or get enlightened or pissed off from my postings is entirely up to them.

You guys can go and inflate your egos here ..... more "entertainment" here.

by uncle_vic Fri Oct 30, 2009 11:59 am

oledi told u guys ma! if u guys know why different persons listen differently, perceive differently, make variously different inferences, then u are already half way there! Need Help - Speaker Power Handling Icon_lol

by hoyhoysum Fri Oct 30, 2009 2:24 pm

Strange I wrote a lenghty in this post but what happen to it? I find a number of times i posted went missing.....I am upset because it wasted my time typing such a lenghty post and now gone. Anybody vouch that he or she see my post earlier coz i am worried to much hifi is getting to my head...

by mugenfoo Sun Nov 01, 2009 6:47 pm

hoyhoysum wrote:Strange I wrote a lenghty in this post but what happen to it? I find a number of times i posted went missing.....I am upset because it wasted my time typing such a lenghty post and now gone. Anybody vouch that he or she see my post earlier coz i am worried to much hifi is getting to my head...

curious question.... what system r u playing ?

by jsng Tue Nov 03, 2009 2:12 pm

Hi guys

I am back .... finally i have gotten myself the followings:
- Onkyo TX-SR706
- B&W DM602 S1 (get from a nice forumer here Need Help - Speaker Power Handling Icon_smile

)
- QED Classic 79

Initially i am pairing this DM602 with my older Marantz SR4400 before passing it to by younger brother, and i can feels that there are some details that cannot be heard of and the bass is not that solid ... however when pairing it with another monitor audio (older generation that i have forgotten about the model) and the wharfedale diamond 9.1, those details are there. With the advise of my fren, it seems that my Marantz is not able to push the speaker well.

And after having such a longer discussion with you all and with so many valuable output, i have decided to go for the Onkyo which is offering higher power, and the result is positive. When i first pair this DM602 S1 with the Onkyo 706, (without bi-amping), the result is pretty impressive, can hear more details, both bass and treble response seems better, but the sound seems way too "bright" to me, and i wonder whether this is the characteristics of the speaker or the amp as power is no longer an issue.

However i have also discovered that i am using a "customized" jumper for the DM602, where i had used a short pair of QED Silver to play the jumper role due to the original jumper is missing. So i decided to give it a try by bi-amping it and guess what? after pairing it with another pair of the entry-level QED Classic 79, the sound has improved much more ... at least its up to my taste now Need Help - Speaker Power Handling Icon_biggrin

when listening to those audiophile CDs in pure audio mode, its not as "warm" as what my current NAD302 + Wharfedale Diamond 9.1 is offering, but its pretty neutral to me now. Off course when i comes to movie, its very enjoyable and exciting, and its a new experience to me.

Anyway, really appreciate your help in clearing my doubts on power output so that i didnt miss this lovely Onkyo 706 Need Help - Speaker Power Handling Icon_biggrin

[quote="mugenfoo"]

jsng wrote:So looks like the most scary thingy is when the amp is not able to deliver sufficient power to the speaker As compared to slightly over powered ...

...
Also, the best pairing up of speakers and amp would be your own ears.
And generally, it is always better to have a more generous amp power
than what is demanded by the speakers. With the trained ear, the
symptom of insufficient power from the amp to the speakers is extremely
audible even before signals start to clip. The sound is as @WongKN
described when ample power is delivered to the speakers. You get a more life-like, more open, sound. If Not enuff power, the sound is very flat, bland, poor muddled bass, smeared highs, etc etc. Basically a big pile of shitty sound.

Thanks Mugenfoo .. u r right, my new setup is now much more open and dynamic, where it can present my details, from pure audio to movie. I think i might have gotten my self a good amp that is able to drive my speaker nicely.

by mugenfoo Tue Nov 03, 2009 6:19 pm

Glad u found better sound from more power. There are some who say that more power would only make the sound worse. Obviously they have not heard how well loudspeakers can perform when a good amp upgrade is added into the hifi chain.

This validates the importance of power in all aspects of the hifi chain. Even right from the source. Rock solid PSUs for all equipment, superbly designed circuits (without getting into the technical details) with top-notch components deliver + overall great design engineering elevates the sonic qualities.

by car o scope Tue Nov 03, 2009 10:31 pm

I have been to a shop which told me power is important but not everything.
But, to me, if the amp has good power, there is no harm of having more.
Maybe I am greedy.. hahahahahaha... Need Help - Speaker Power Handling Icon_razz

by mugenfoo Tue Nov 03, 2009 11:52 pm

One cannot have "too much" (amp)power...

Just "good" power is never enough.

by car o scope Wed Nov 04, 2009 8:04 am

.....and also control, right?

by mugenfoo Wed Nov 04, 2009 9:39 am

more power => better control. Better damping factor. therefore can control the speaker better.

by ryder Wed Nov 04, 2009 10:09 am

The B&W DM602 is an efficient speaker. I reckon it is not so much of a power issue but the quality and characteristics of the Onkyo unit compared to the Marantz amp.

by uncle_vic Wed Nov 04, 2009 11:58 am

It's about power and how it is delivered when required! Not too much and not too little. Everyone reading hifi magazines will need some kind of proof of this hypothesis. Difficult to proof or show. so most of the time is academic discussions.

by jsng Wed Nov 04, 2009 12:13 pm

BTW ... i am just curious about the volume level ... with this new Onkyo, i tends to turn the volume till -14 to -20 most of the time, where if i were to compared to my old Marantz, i hardly turn below -20 and usually maintain at -22 till -24.

Anyway, i am still confused on this volume level, what does that mean actually? when it says -20db? shouldnt the standard volumne be 0db?

by ryder Wed Nov 04, 2009 12:30 pm

The volume level on amps don't prove anything. It is more accurate to measure what SPLs(in dB) you are getting from your listening chair. Your speakers sensitivity rating should give a good indication of the SPLs you are getting with 1W of power at a listening distance of 1m away. Usually the average listening level is around 75-85dB. Some folks who like to listen loud may crank it up to 90dB or above. There won't be any sound from the speakers if it's 0dB.

Some folks use low-powered tube amps on efficient speakers with high sensitivities with good results. On the other hand, huge power hungry speakers would require massive power to come alive. It depends on the speaker design when choosing a matching amp. A good quality amp is more important than a high-powered amp. Also, power ratings of most mass-market AV amps don't quite reflect how powerful those amps are. Some well-designed integrated amps with lesser wattage can sound more powerful than AV amps with higher power ratings on paper.

by mugenfoo Wed Nov 04, 2009 4:52 pm

uncle_vic wrote:It's about power and how it is delivered when required! Not too much and not too little. Everyone reading hifi magazines will need some kind of proof of this hypothesis. Difficult to proof or show. so most of the time is academic discussions.

Too much power is only detrimental when it overloads the speakers and fries the coils / panels / etc etc.

of course, if the massive power is being amplified to the point of audible distortion. This is also bad.

by tycham Wed Nov 04, 2009 5:47 pm

jsng wrote:BTW ... i am just curious about the volume level ... with this new Onkyo, i tends to turn the volume till -14 to -20 most of the time, where if i were to compared to my old Marantz, i hardly turn below -20 and usually maintain at -22 till -24.

Anyway, i am still confused on this volume level, what does that mean actually? when it says -20db? shouldnt the standard volumne be 0db?

Maybe this would help you to understand.

http://forum.ecoustics.com/bbs/messages/34579/498440.html

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