Underpowered speakers

[jdub15]

What is the harm of underpowered speakers? For instance, would it be bad to have only 130 watts going to a speaker rated for 50-500? What would the speaker performance be related to a lower speaker rated for 20-250 getting the same power? Looking at the Polk RTi A9 versus the RTi A7.

 

[lsiberian]

What is the harm of underpowered speakers? For instance, would it be bad to have only 130 watts going to a speaker rated for 50-500? What would the speaker performance be related to a lower speaker rated for 20-250 getting the same power? Looking at the Polk RTi A9 versus the RTi A7.

For every time you double the wattage you increase the db by 3. Which is the first time you notice it in non-critical listening.

500 watts is probably the point at which the driver excursion reaches it Wmax. However many drivers distort badly at about 1/3rd of wmax. This varies but 130 would be plenty of power for a Polk RTi IMO. I don't suggest ever feeding it 500 or 250 watts respectively. You will probably not like the sound.

If your concerned about power the RTi 9s then I suggest you pick up a Behringer Ep2500 do the fan mod and use that to drive the speakers.

you will need some kind of pre-amp, but you would have plenty of good clean power.

 

[skers_54]

Just for clairification, the property is xmax, not wmax .

Think of an amp as a car engine. Cruising around town doesn't require much power. But accelerating to reach highway speed will require much more, as well as show if your car is underpowered.

The issue with underpowering speakers is that they can be damaged when an amp is driven into clipping. This will occur when trying to achieve higher and higher sound levels. At moderate levels, speakers will essentially sound the same if the amps are operating within thier limits. If you have a large room or inefficient speakers, more power will be required to reach the same spl. This increases the demands on the amp and makes clipping more likely.

Most of the time, only a couple watts will be used (continuously). In your case, there probably won't be a noticible difference between 130 watts and 500 watts as you will not be using the reserve power (except on dynamic peaks). Many speaker power ratings are also misleading, as a speaker can fail in several different ways.

Basically, it will be fine to use a lower power amp as long as you're responsible with the volume control. Just turn it down if you hear distortion. More power will give you better dynamics and more reserve, which are both good things.

 

[jdub15]

This is what I am kicking around in my head....Denon AVR-3808CI with the Polk RTi A9 or A7, CSi A6, FXi A6, and a sub. Is this a good system? Any recommendations? Looking to stay around $5K. Totally new to the audio world.

 

[mtrycrafts]

Just for clairification, the property is xmax, not wmax .

....

Right wmax is one of our fine contributors here

 

[speakerman39]

Right wmax is one of our fine contributors here

Fine contributors? I would say a term like genius would be more fitting.

 

[no. 5]

What is the harm of underpowered speakers?

There is none. Speakers are only damaged by too much power, ether by exceeding the mechanical or thermal limits of the speaker.

500 watts is probably the point at which the driver excursion reaches it Wmax.

500 watts would put a lot of consumer loudspeakers past both the maximum linear excursion (Xmax) and the mechanical excursion limit (Xlim), I could be wrong, but I think Polk is being optimistic in saying that that speaker can handle 500 watts.

 

[mulester7]

What is the harm of underpowered speakers?

.....example....a pair of speakers are rated 150 watts-rms continuous....they are being pushed by a receiver rated 2 X 50 watts-rms-continuous, and the amp-sections clip at 67 watts asked....clipping the amp-sections in such a manner sends maximum-distortion to the voice-coils, many times frying them....I see Mtry is still alive and well .....

.....Samurai my butt.....

 

[annunaki]

.....example....a pair of speakers are rated 150 watts-rms continuous....they are being pushed by a receiver rated 2 X 50 watts-rms-continuous, and the amp-sections clip at 67 watts asked....clipping the amp-sections in such a manner sends maximum-distortion to the voice-coils, many times frying them....I see Mtry is still alive and well .....

.....Samurai my butt.....

Welcome back fine sir.

Distortion is not what causes driver failure in and of itself. It is the increased power level and lack of linearity caused by distortion which can result in thermal or mechanical failure.

Full on amplifier clipping is typically double the output of the .1% thd output rating of the amplifier.

Example: If an amplifier will do 70 watts rms at .1% thd it will do around 140 watts when fully clipped. This easily exceeds the thermal limit and mechanical limit for most 100 watt rms rated speakers.

Let's say that this amplifier partially clips and is still doing 120 watts regularly. Thermal failure will set in albeit not as quickly. Mechanical failure is still a high probability.

Thermal failure is too much heat built up over time.

 

[mulester7]

Welcome back fine sir.

.....thanks, Moderator Annunaki....the soup kitchen shut down .....

 

[lsiberian]

Just for clairification, the property is xmax, not wmax .

Think of an amp as a car engine. Cruising around town doesn't require much power. But accelerating to reach highway speed will require much more, as well as show if your car is underpowered.

The issue with underpowering speakers is that they can be damaged when an amp is driven into clipping. This will occur when trying to achieve higher and higher sound levels. At moderate levels, speakers will essentially sound the same if the amps are operating within thier limits. If you have a large room or inefficient speakers, more power will be required to reach the same spl. This increases the demands on the amp and makes clipping more likely.

Most of the time, only a couple watts will be used (continuously). In your case, there probably won't be a noticible difference between 130 watts and 500 watts as you will not be using the reserve power (except on dynamic peaks). Many speaker power ratings are also misleading, as a speaker can fail in several different ways.

Basically, it will be fine to use a lower power amp as long as you're responsible with the volume control. Just turn it down if you hear distortion. More power will give you better dynamics and more reserve, which are both good things.

Heheh but I thought since he's such a great contributor that we could rename the parameter. What it's named is really a matter of semantics

 

[skers_54]

Heheh but I thought since he's such a great contributor that we could rename the parameter. What it's named is really a matter of semantics

Agreed. Maybe we could rename cabinet resonance or invent a parameter to measure subwoofer integration after him. Since he knows more about those two areas that pretty much everyone.

 

[mtrycrafts]

Fine contributors? I would say a term like genius would be more fitting.

I didn't want him to perish due to a swollen head

 

[mtrycrafts]

.....thanks, Moderator Annunaki....the soup kitchen shut down .....

Still here, yes I guess if the kitchen shut down, no more hungry folks out there

 

[speakerman39]

I didn't want him to perish due to a swollen head

LOL, too funny. But, you do have a point.

Cheers,

Phil

 

[mulester7]

Still here, yes I guess if the kitchen shut down, no more hungry folks out there

.....hey, MtryCrafts, you are doing fine, I see....Guys, Mtry told me a couple of years ago subs hum when they don't know the words....yes, others will verify this....just kidding, I actually accused him of saying it....MtryCrafts is sharp for sure.....

 

[Perry the sound guy]

What is the harm of underpowered speakers? For instance, would it be bad to have only 130 watts going to a speaker rated for 50-500? What would the speaker performance be related to a lower speaker rated for 20-250 getting the same power? Looking at the Polk RTi A9 versus the RTi A7.

Q. Is it possible to underpower a speaker?
A. No! That is just as dumb as it sounds.
I have been in this business over 40 years, and believe me, speakers are damaged by too MUCH power, not too LITTLE!
If you are blowing speakers, switching to a larger amp will not stop it. You wil just blow them faster.
To prevent blowing speakers - Turn It Down!
If you are the kind of person that pushes things until something gives, it will probably result in blown speakers. (And speeding tickets.)
As far as distortion; the speaker does not know if the signal is distorted or is supposed to sound that way. It just moves to reproduce whatever signal it is given. And the point is moot because most modern day power amps have clip limiting so they don't distort anyway.
Shockingly, I have seen suggestions that you should use a power amp with 2 or 3 times the power of the speaker. That will be great if you like blown speakers, but really is a bad idea. A 200 watt speaker needs a 200 watt power amp. That is what the ratings are for!!!!!

 

[AcuDefTechGuy]

Q. Is it possible to underpower a speaker?
A. No! That is just as dumb as it sounds.
I have been in this business over 40 years, and believe me, speakers are damaged by too MUCH power, not too LITTLE!
If you are blowing speakers, switching to a larger amp will not stop it. You wil just blow them faster.
To prevent blowing speakers - Turn It Down!
If you are the kind of person that pushes things until something gives, it will probably result in blown speakers. (And speeding tickets.)
As far as distortion; the speaker does not know if the signal is distorted or is supposed to sound that way. It just moves to reproduce whatever signal it is given. And the point is moot because most modern day power amps have clip limiting so they don't distort anyway.
Shockingly, I have seen suggestions that you should use a power amp with 2 or 3 times the power of the speaker. That will be great if you like blown speakers, but really is a bad idea. A 200 watt speaker needs a 200 watt power amp. That is what the ratings are for!!!!!

I also believe in the power rating.

This thread is 9YR old, so I can't remember much about it.

But did anyone here on Audioholics recommend buying a amp that is 3 times the max rated power for speakers? Gotta be someone from AVS or some other forums, right?

 

[everettT]

Like when speakers can handle 1000w continuously? Most consumers dont need a ton of power regardless of the speakers, most.

 

[Paul DS]

What is the harm of underpowered speakers? For instance, would it be bad to have only 130 watts going to a speaker rated for 50-500? What would the speaker performance be related to a lower speaker rated for 20-250 getting the same power? Looking at the Polk RTi A9 versus the RTi A7.

Most speaker companies state a minimum and maximum amount of watts their speakers are designed to handle. If your receiver/amplifier falls into their suggested power, you should be just fine. A good rule of thumb is: If it sounds distorted, TURN IT DOWN!