Underpowered amps vs overpowered amps

mandark

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I would like to know if underpowered amps or overpowered amps are more dangerous to speakers?

Experts kindly share your knowledge and experience.
 
underpowered amps are more dangerous, the higher the power of the amp in general the better the control over the speaker. Think of it as a car which has a lot of power - your overall performance is better even though you never touch 200 kmph

cheers
 
Hi,
I think.........underpowered amp are more dangerous then the overpowered ones........but I would also like to know from the experts about this, as I'm also looking for an amp for my stereo speakers which are 6 ohms / Power (W, long/short term)100 / 140 watts / 88 db / 45 - 20,000 Hz as to how much wpc would be sufficient / safe enough.

I could find this link........

Confused about amplifier-speaker relation - Page 2 - diyAudio

Thanks ...............
 
It is not that easy to answer this question as there are a number of factors involved. One important factor is the sensitivity of the speakers. Higher sensitivity speakers are easier to drive and there much more prone to damage with a powerful amp.

Think of it this way. Instead of the amps driving the speakers, think of the speakers as a suction pump drawing water (power) from the amp. If the suction is more than what is available in the amp, the amp will start to get dry and damaged. This is called clipping.

If the tank in the speaker is full, there is more water (power) available in the amp, and the suction continues, there is going to be an overflow in the speakers. This will lead to distortion of sound, and eventual damage of speakers.

If you think of this in this manner, you will understand that the two have to be ideally matched.

Cheers
 
Hi,
I think.........underpowered amp are more dangerous then the overpowered ones........but I would also like to know from the experts about this, as I'm also looking for an amp for my stereo speakers which are 6 ohms / Power (W, long/short term)100 / 140 watts / 88 db / 45 - 20,000 Hz as to how much wpc would be sufficient / safe enough.

I could find this link........

Confused about amplifier-speaker relation - Page 2 - diyAudio

Thanks ...............
adding to what Odyssey had to say, you really cannot go wrong if your amp has more power, as long as you have a pre amp turned low enough, your ear drums will blow before the speaker :)

regarding underpowered amps, since amps have a rated capability.. somewhere above the capability the components cannot handle the higher power as they are not really designed for it, resulting in a clipped output..a clipped waveform is like a squarish wave and usually has more power than the original wave and additionally the distorted signal could also have a DC component whch can go into the speaker coils and resulting in it getting overheated/burnt.

but since speakers are Passive power devices , you need not go by the power rating..you should go by what the speaker+room needs. in most cases for an 88dB speaker in a regular room 30-60W amp is more than enough.
 
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If the tank in the speaker is full, there is more water (power) available in the amp, and the suction continues, there is going to be an overflow in the speakers. This will lead to distortion of sound, and eventual damage of speakers.

If you think of this in this manner, you will understand that the two have to be ideally matched.

Cheers

in an overpowered amp, is not the ideal matching between the speaker and the amp achieved by use of the volume control knob?
 
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To be more specific is Denon 1911 going to be an underpowered amp when it is required to drive speakers Morduant Short Aviano 2 and Avinao 6 (both being considered as fronts) with Aviano 5 as center?
 
a very obviuos question would be.. on denon 1911 we see per channel rms to be rated as 90watt / 8ohms and 125 watt/ 6 ohms and i pretty much understood that for same power source more the target impedance less the power realized. however on the aviano 2 i see that it says 10watt-120watt at 4ohm to 8ohm. so the doubt is whether the 120watts of max power handling capability is for 4ohms impedance or 8ohms. if it is at 4ohms them the same figure will be much much lesser at 8ohms. any pointers anyone?
 
hmm

im in the process of procuring a 175W/channel @8ohms Classe AMP to drive 65rms speakers

i guess i belong to "theres nothing like an overpowered amp " group!
 
hmm

im in the process of procuring a 175W/channel @8ohms Classe AMP to drive 65rms speakers

i guess i belong to "theres nothing like an overpowered amp " group!

Magma
You didnt mention the speaker sensitivity ? Then we will know whether 175w amp is suitable for all case.
 
one speaker is
Anechoic Chamber 89 dB
Typical Listening Room 91 dB

not exactly low sensitivity

the other is 86db
 
Here is my research so far after going through a lot of text elsewhere on the ether.
The 6ohms per channel power of 125Watt of Denon is the peak power that it can output per channel as per this link which explains the same for denon 3311

Denon Launching the AVR-3311, AVR-1911 and AVR-1611 AV Amplifiers - Softpedia

hence this means that in terms of certain spikes in music the denon 1911 can send out a max power per channel of 125 watts which is more of short term power output capability.

Again on the other side the Aviano 2 have power rating of 10-120 watts which means that the short term power handling capability of it is 120 watts (refer example link below that says the higher number for aviano 6 is 150 watts which matches the same specified at aviano 6 specification Mordaunt Short Aviano 6 Floorstanding Speakers)
. This short term power handling capability signifies that in terms of sudden rise in music power the speaaker can handle max power of 120 watts.

Moreover this does not signify that the speaker has to be run all the time at 120 watts of power and I am sure if done that the speaker coils are going to be heated up soon and burn out. So Aviano 2 should be a very good match with Denon 1911 and the additional 5 watts per channel over the short terms power of aviano 2 would not be an issue of concern since that will only be output by the 1911 only when it is being run at its max volume which i think will never happen in normal home use. Even during the demo we heard the denon 1911 at 40% volume and were thinking if we would be using them at all at this volume back at our homes.

For the Aviano 6 I think in a similar manner the max value of 150 watts short term power would never be reached and would be in a manner safeguard that the amp will not accidentally burn out the speaker at higher instantaneous powers.

Hence I think the only other concern be about becoming underpowered. More specifically will the avianos not run at average power of 50 to 60 watts under normal home conditions?

I looked up a couple of more reviews and found that the sesitivity of the polk tsi 300 was 90db and the same for avianos is 88db which means that although the polks are more easier to drive speakers than avianos with which we demoed denon 1911 at the profx store along with profx fusion 6 towers which also have the similar sesitivity of 89db and hence based on all these figures I do think that 1911 should not be a issue for driving avianos as it will require somewhat more power than the polks but will not fall short of power since we were hearing the polks at mere 35% to 40% of the volume and it was pretty loud and raising it marginally higher willl not harm the amp in getting the same loudness as the polks. Getting 3311 or 2311 would be an overkill for home situations.
 
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Haisaikat has put it admirably. I will add that at the end of the day you do not j=know how well your speakers and receiver are matched until you actually use them for some time( in the absence of auditioning them), your room plays a part in the experience, and so do listening volumes. In the end I guess what I'm trying to say is that each person has his own experience, but unless you stop and have a meal at a restaurant yourself, you wont really know how good the food is!
 
Here is my research so far after going through a lot of text elsewhere on the ether.

I looked up a couple of more reviews and found that the sesitivity of the polk tsi 300 was 90db and the same for avianos is 88db which means that avianos are more easier to drive speakers than polks with which we demoed denon 1911 at the profx store along with profx fusion 6 towers which also have the same sesitivity of 89db and hence based on all these figures I do thaink that 1911 should not be a issue for driving avianos and getting 3311 or 2311 would be an overkill for home situations.

Hi saikat,

I think more sensitivity means less effort needed to drive the speakers.

I have the MS Aviano -2 speakers and Marantz PM 6003 amp(rated at 45w rms/channel). The speakers are driven effortlessly by the amp. I can't sit in the room of 10x12 ft, beyond 10'o Clock position in the Volume control on good recorded Cds, and the source ie Marantz CD 5003.

N.Murali
 
Hi saikat,

I think more sensitivity means less effort needed to drive the speakers.

I have the MS Aviano -2 speakers and Marantz PM 6003 amp(rated at 45w rms/channel). The speakers are driven effortlessly by the amp. I can't sit in the room of 10x12 ft, beyond 10'o Clock position in the Volume control on good recorded Cds, and the source ie Marantz CD 5003.

N.Murali

Thanks Murali. I have corrected my post. Moreover I saw that the short term power of the marantz you have is 60watts at 4ohms and hence I think that if your marantz can drive the avianos well, the denon 1911 should not be a problem.
 
I was again going through the bottom url which explains the same thing about how clipping can cuase damage

<meta name="description" content="Klipsch audio systems provide the true audio/video lover a wide variety of high performance loudspeakers and loudspeaker systems for music and home theater entertainment centers, including iPod speakers, multimedia s

I wonder that if we use a overpowered amplifier and power delivered overtakes the speaker capability then speakers can get damaged. In this respect our best bet will be the volume control as others in this forum has suggested to control the max power that can go to the speakers.

In similar terms can we not also use the volume control for underpowered amps in such a manner so that even if there is a high surge in music the amp will still be able to deliver that at the given volume and still not go into clipping?
 
I think I have a sigh of relief now when i found the following protection feature available in Denon 1911. It appears to me that clipping of amplifier will be automatically be protected by Denon amps. Not sure if this is present in Onkyo or Yamaha

Can I use 4 ohm loudspeakers with my Denon receiver or power amplifier?

Can I use 4 ohm loudspeakers with my Denon receiver or power amplifier?
Yes you can.

To understand this a bit better, first realize that all amplifiers are designed to deliver a signal into an electrical "load" or resistance presented by the loudspeaker. We measure resistance in units called "ohms" (after the German physicist Georg Simon Ohm, 17871854).

Conventional wisdom makes an 8 ohm loudspeaker load the most acceptable because it "protects" the amplifier from delivering too much current. A 4 ohm loudspeaker can encourage a marginally designed amplifier to deliver more current than it comfortably can.

However, you should remember that a loudspeakers impedance rating is a nominal or average one: A speaker rated at 8 ohms may actually vary from 5 (sometimes even less) to 20 ohms or higher, depending on the frequency at which you measure the impedance. We call this reactance. (Dont worry about this too much -- good speaker engineers are well aware of these variations and take them into consideration when designing products.)

In general, youll find that Denon products are designed to function with a wide variety of loudspeakers and have power supplies and output circuitry more than able to meet the current demands of low impedance loads. If using 4 ohm rated speakers, common sense should always be taken as to the volume level setting, as it is easier to overdrive or "clip" an amplifier with 4 ohm speakers than with speakers with a rating of 6~16 ohms.

In the rare event that very low impedances tax the amplifier, quick acting circuitry will protect it from damage. If unusual operating conditions trigger this circuitry, the word "PROTECTION" will appear on the units front panel. If this happens, simply turn the unit off, wait a moment or two, and turn the unit back on again. The protection circuitry will automatically reset.
If it re-engages, check your system for possible malfunctions such as intermittently shorting speaker wires, damage speaker drivers or it may be as simple as turning the volume down a little as not to cause the amplifier(s) to go into protection due to overdriving them
 
I would like to know if underpowered amps or overpowered amps are more dangerous to speakers?

Experts kindly share your knowledge and experience.

1. "underpowered amps are more dangerous"

Statements like this are considered a Myth!
However, Underpowerd amps driving at full power is a different story altogether.

To be more correct, the above statement (1) is actually incomplete. it depends on the context, speaker & amp combination together. (See below)

You can have a setup with an underpowered amp and never ever ever end up killing (blowing) your drivers, by not driving at full power.
The problem occurs when, the amplifier is driven to the point that it can no longer "amplify the signal"! It is now that you could run into big trouble and blow ur speakers. At this point, the amplifier starts clipping the signal and output is like a square wave, with lots of dc current.
Note that this is no longer RMS (ac power has peaks now and then), now replaced by continuous dc power (a 'continuous peak'), which in turn generates heat continuously.
Now depending on how much dc current is generated, plus the drivers thermal capacity, together determines if they will 'blow'. Basically depends on the thermal limit of your speaker drivers.

Hence, for instance if you have a powerful amp, and an even more powerful speakers, but combination is so powerful that amp never reaches even 75% its capacity, then one need not worry. It is when you start pushing the amp harder, then it becomes an issue.
Now consider, a low powered speaker, with an even lower capacity amp. Now since the decibel output is low, the user tends to obviously increase the volume to push harder, and then if the amp starts clipping...you know what happens.

As simple as that. :cool:

To put it into better perspective, an amplifier as the name stands - amplifies the signal. Now if you input a signal that has is already amplified, the amplifier will now try to amplify the signal even more.
It will try, not necessarily succeed! If input signal was powerful, then the clipping can occur way way sooner even at 10% of the volume.
Only an complete idiot will try this. :clapping: :rolleyes:

Sometimes when you have a mike and u would have noticed a sudden screech from speakers.
This is the very reason why it happens. Imagine what happens when you take the mike near speakers. A continued process of amplification, a few seconds is all it needs now to kiss your speakers good bye!!
 
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Unlike underpowered amps (which depends on the combination of speakers & amp at hand), it is overpowering which can cause real damage.

Here's why.
Consider you have an hi powered amp and a not so hi powered speaker. Now consider your amp pushing your speakers to the limit (happens way before the amp reaches its amplification limit). But since amplification is basically amplifying ac, it means peaks occur only now and then. (hence there is a head room./ This is why people push the speakers a bit more with a more powerful amp).
However, if the ac peak is large enough, your driver/speaker is done for good.

Your speakers have a mechanical limit too like the thermal limit earlier, it is mechanical motion of driver that produce sound, moving back and forth. Basically, more they move back and forth, more the sound generated. This happens with more input power. Ask urself, how far can drivers, which are essentially made of paper, be pushed back and forth? There is a mechanical limit! So if a peak occurs, where it cross this corresponding limit, it has the potential to tear the speakers. A few peaks or even one and you are done with your speakers.
 
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