Harness the Power: How to Create a Reliable Dual 12V DC Power Supply
Powering Amplifiers and Speakers: How Not to Risk Damage (2020)
Many of you ask us about the power match between amplifiers and speakers. Commonly, we are asked if it is imperative that the power delivered by the amplifier and that admissible by the speakers are identical, or if an amplifier that is too powerful can damage a pair of speakers unable to accept the power delivered. Here are some answers and solutions to prevent any problem, especially in home cinema.
Understand the power of an amplifier
The power of a Hi-Fi or home cinema amplifier is expressed in Watts. Contrary to what is sometimes understood, the power indicated is not that delivered permanently – as is the case with a light bulb for example – but the maximum power that the amplifier can deliver. Indeed, depending on the intensity of the incoming audio signal and the gain applied to it (position of the volume potentiometer), the power delivered is variable. A stereo Hi-Fi amplifier given for 2×50 W can therefore deliver from a few milliwatts to 2×50 W.
What is the speaker power handling?
In practice, this is the amount of current that the speaker's woofer coil can take, given that it is the most heavily loaded driver. Indeed, it is assumed that the bass speaker receives about 7 times more power than a tweeter for example. This is related to the lack of sensitivity of the human ear with respect to low frequencies. The mechanical properties of the coil determine its power handling: material used (copper, aluminum or silver), wire diameter and length. If this allowable power is exceeded, the coil may melt or burn.
Electrical and acoustic power
Some manufacturers indicate an admissible power which is not the electrical power admissible by the coil. Indeed, if the woofer coil can absorb 100 W, such a power will cause an excursion of the loudspeaker membrane that is infinitely too high, which will potentially expose it to mechanical damage (tearing) and generate a high distortion, or even dangerously expose the amplifier which will be opposed to an abnormal resistance (impedance).
Is a 50 W amplifier dangerous for 100 W speakers?
Potentially, yes, if it is used to its full potential and the loudspeakers are difficult to drive (large drivers, large load volume, low nominal impedance). Because the enemy of speakers is not so much power as the distortion generated by insufficient power. A poorly powered 50 W amplifier can generate, under extreme conditions, square signals or supply direct current to loudspeakers accepting 100 W, whose coils can then deteriorate and melt. The loudspeaker is then "destroyed" while its admissible power is on paper higher.
Is a 100W amplifier dangerous for 50W speakers
Yes, if it is used to the maximum of its possibilities. On the other hand, if it is used at about half its power, it will calmly power the speakers and offer a coherent sound, in short a better musical experience.
Are manufacturers cheating with the power of their amps?
No, but as far as home cinema is concerned, the powers expressed are often expressed at 1 kHz and not from bass to treble (20 Hz to 20 kHz), what is more with high distortion (1% to 10% Sometimes). For what ? It's a little complicated. The ideal would be to know the power delivered simultaneously to all channels, from 20 Hz to 20 kHz, with low distortion (0.08% for example), as for Hi-Fi amplifiers. The problem is that if in HiFi the 2 channels are used permanently, this is rarely the case in home cinema, especially since the surround channels are not at all intended to reproduce very bass frequencies. Also the manufacturers do not communicate on this simultaneous multi-channel power, which would worry – wrongly – their customers, given the low values. Take for example the Yamaha RX-V4A home cinema receiver, a mid-range model that is quite excellent in its category. Yamaha announces 115 W for 1 powered channel, at 1 kHz and 0.9% distortion. But 80 W for 2 channels driven from 20 Hz to 20 kHz with 0.06% distortion. In other words, the amplifier power supply can deliver 160 W from 20 Hz to 20 kHz and 0.09% distortion. Which, divided by 5 channels, gives 32W per channel, all in action. Admit that 5×32 W is not very selling. However, it is more than enough in absolute terms and as we explained before, no film will require the same power ofall channels at the same time.
5×32 W, is it really enough?
In most cases yes. This statement will be all the more accurate if an amplified subwoofer will be used to reproduce low frequencies instead of the home cinema amplifier. In this case, the 32 W will be developed in the midrange and treble registers, which with medium sensitivity speakers (89 dB for 1 W injected) is equivalent to a sound level of 104 dB at 1 m from each speaker: this is colossal. If no subwoofer is used, then these 32 W will be developed for the low frequencies and about 7 times less power will be devoted to the midrange and high frequencies, i.e. about 4 W, in other words a sound level in these frequencies of 95 dB at 1 m from the speakers: again, it's very high and you have to have very tolerant neighbors...
Home cinema more exposed than Hi-Fi
Listening to a movie is often much more demanding on amplifiers and speakers. Indeed, the dynamic differences are much more marked with the audio track of a film than with most music. Moreover, the level of low frequencies can be massive whereas this register is often "deflated" on CD-Audio. On the other hand, we gladly listen to a film with a high volume, even very high.
Set up your home cinema amplifier properly
Although most home cinema amplifiers are delivered with a microphone and incorporate a quality self-calibration system, the measurements taken and the corrections decreed by the on-board software must be checked, particularly with regard to the cutoff frequency. and eventual equalization. This is essential if there is no subwoofer, as the low frequencies of the surround, center and LFE (.1) channels will be mixed to the main speakers.
It is therefore necessary to check that the low cut-off frequency of the speakers is not lower than that communicated by the manufacturer. For example, a speaker reproducing frequencies from 80 Hz to 20 kHz must under no circumstances receive frequencies below 80 Hz. Because the coil of the bass speaker can heat up and melt. This is especially true for compact or satellite loudspeakers equipped with small drivers (8 or 10 cm) and very small coils.
If the amplifier after self-calibration has fixed the cut-off frequency at 60 Hz, it will have to be corrected manually. Also pay attention to the possible equalization of low frequencies by the home cinema amplifier. Plus 2dB at 50Hz equals a doubling of power output.
The many advantages of the subwoofer
In addition to having a matching loudspeaker and amplifier, developed for the reproduction of low frequencies (large coil, high power of the amplifier), the subwoofer allows – with a home cinema amplifier – to protect the other speakers from any excessive influx of current from the home cinema receiver. The condition is therefore to declare the speakers as SMALL or SMALL in the menu of the home cinema receiver. Therefore the risk of "grilling" the speakers is minimal.
Harness the Power: How to Create a Reliable Dual 12V DC Power Supply
Powering Amplifiers and Speakers: How Not to Risk Damage (2020)
Many of you ask us about the power match between amplifiers and speakers. Commonly, we are asked if it is imperative that the power delivered by the amplifier and that admissible by the speakers are identical, or if an amplifier that is too powerful can damage a pair of speakers unable to accept the power delivered. Here are some answers and solutions to prevent any problem, especially in home cinema.
Understand the power of an amplifier
The power of a Hi-Fi or home cinema amplifier is expressed in Watts. Contrary to what is sometimes understood, the power indicated is not that delivered permanently – as is the case with a light bulb for example – but the maximum power that the amplifier can deliver. Indeed, depending on the intensity of the incoming audio signal and the gain applied to it (position of the volume potentiometer), the power delivered is variable. A stereo Hi-Fi amplifier given for 2×50 W can therefore deliver from a few milliwatts to 2×50 W.
What is the speaker power handling?
In practice, this is the amount of current that the speaker's woofer coil can take, given that it is the most heavily loaded driver. Indeed, it is assumed that the bass speaker receives about 7 times more power than a tweeter for example. This is related to the lack of sensitivity of the human ear with respect to low frequencies. The mechanical properties of the coil determine its power handling: material used (copper, aluminum or silver), wire diameter and length. If this allowable power is exceeded, the coil may melt or burn.
Electrical and acoustic power
Some manufacturers indicate an admissible power which is not the electrical power admissible by the coil. Indeed, if the woofer coil can absorb 100 W, such a power will cause an excursion of the loudspeaker membrane that is infinitely too high, which will potentially expose it to mechanical damage (tearing) and generate a high distortion, or even dangerously expose the amplifier which will be opposed to an abnormal resistance (impedance).
Is a 50 W amplifier dangerous for 100 W speakers?
Potentially, yes, if it is used to its full potential and the loudspeakers are difficult to drive (large drivers, large load volume, low nominal impedance). Because the enemy of speakers is not so much power as the distortion generated by insufficient power. A poorly powered 50 W amplifier can generate, under extreme conditions, square signals or supply direct current to loudspeakers accepting 100 W, whose coils can then deteriorate and melt. The loudspeaker is then "destroyed" while its admissible power is on paper higher.
Is a 100W amplifier dangerous for 50W speakers
Yes, if it is used to the maximum of its possibilities. On the other hand, if it is used at about half its power, it will calmly power the speakers and offer a coherent sound, in short a better musical experience.
Are manufacturers cheating with the power of their amps?
No, but as far as home cinema is concerned, the powers expressed are often expressed at 1 kHz and not from bass to treble (20 Hz to 20 kHz), what is more with high distortion (1% to 10% Sometimes). For what ? It's a little complicated. The ideal would be to know the power delivered simultaneously to all channels, from 20 Hz to 20 kHz, with low distortion (0.08% for example), as for Hi-Fi amplifiers. The problem is that if in HiFi the 2 channels are used permanently, this is rarely the case in home cinema, especially since the surround channels are not at all intended to reproduce very bass frequencies. Also the manufacturers do not communicate on this simultaneous multi-channel power, which would worry – wrongly – their customers, given the low values. Take for example the Yamaha RX-V4A home cinema receiver, a mid-range model that is quite excellent in its category. Yamaha announces 115 W for 1 powered channel, at 1 kHz and 0.9% distortion. But 80 W for 2 channels driven from 20 Hz to 20 kHz with 0.06% distortion. In other words, the amplifier power supply can deliver 160 W from 20 Hz to 20 kHz and 0.09% distortion. Which, divided by 5 channels, gives 32W per channel, all in action. Admit that 5×32 W is not very selling. However, it is more than enough in absolute terms and as we explained before, no film will require the same power ofall channels at the same time.
5×32 W, is it really enough?
In most cases yes. This statement will be all the more accurate if an amplified subwoofer will be used to reproduce low frequencies instead of the home cinema amplifier. In this case, the 32 W will be developed in the midrange and treble registers, which with medium sensitivity speakers (89 dB for 1 W injected) is equivalent to a sound level of 104 dB at 1 m from each speaker: this is colossal. If no subwoofer is used, then these 32 W will be developed for the low frequencies and about 7 times less power will be devoted to the midrange and high frequencies, i.e. about 4 W, in other words a sound level in these frequencies of 95 dB at 1 m from the speakers: again, it's very high and you have to have very tolerant neighbors...
Home cinema more exposed than Hi-Fi
Listening to a movie is often much more demanding on amplifiers and speakers. Indeed, the dynamic differences are much more marked with the audio track of a film than with most music. Moreover, the level of low frequencies can be massive whereas this register is often "deflated" on CD-Audio. On the other hand, we gladly listen to a film with a high volume, even very high.
Set up your home cinema amplifier properly
Although most home cinema amplifiers are delivered with a microphone and incorporate a quality self-calibration system, the measurements taken and the corrections decreed by the on-board software must be checked, particularly with regard to the cutoff frequency. and eventual equalization. This is essential if there is no subwoofer, as the low frequencies of the surround, center and LFE (.1) channels will be mixed to the main speakers.
It is therefore necessary to check that the low cut-off frequency of the speakers is not lower than that communicated by the manufacturer. For example, a speaker reproducing frequencies from 80 Hz to 20 kHz must under no circumstances receive frequencies below 80 Hz. Because the coil of the bass speaker can heat up and melt. This is especially true for compact or satellite loudspeakers equipped with small drivers (8 or 10 cm) and very small coils.
If the amplifier after self-calibration has fixed the cut-off frequency at 60 Hz, it will have to be corrected manually. Also pay attention to the possible equalization of low frequencies by the home cinema amplifier. Plus 2dB at 50Hz equals a doubling of power output.
The many advantages of the subwoofer
In addition to having a matching loudspeaker and amplifier, developed for the reproduction of low frequencies (large coil, high power of the amplifier), the subwoofer allows – with a home cinema amplifier – to protect the other speakers from any excessive influx of current from the home cinema receiver. The condition is therefore to declare the speakers as SMALL or SMALL in the menu of the home cinema receiver. Therefore the risk of "grilling" the speakers is minimal.
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