Amplifier's Power and Effect on Speakers

[Witterings]

Whatever I've read in the past I've been lead to believe that the more powerful an amp is the greater control it has over the speakers therefore more power = better sound.

I was talking to someone just now and mentioned I do a lot of very low volume listening and he said a lower powered amp can be better in that situation. His reasoning, in essence an amp has a range where it performs best and near minimum volmue isn't close to that range where the amp "comes to life". The closer you get to it though the better it performs and having a lesser powered amp you're having to turn it up more for the same volume which will give greater drive to the speakers.

This conversation came up as I'm contemplating swapping my 130 watt amp and a few people have suggested a Lyngdorf 1120 which is 60 watts into 8 ohms.

My room is a reasonable size 16 ft wide x 26 long but the main listening position is closest to the speakers and would be 3 meters away so the amp should be more than enough especially if the furthest part of the room isn't critical listening.

Interested to hear what others thoughts are on this.

 

[staticV3]

Every Amp has peak SNR at max output. But that's all there is to it.
If you can't hear hiss, then you're not losing anything by reducing the volume.

In my experience, headroom does not increase sound quality.
If set to the same SPL, and with all else being equal, the weak Amp running at 90% will sound identical to the overkill Amp running at 20%.

 

[Koeitje]

Just calculate what kind of SPL level you want at your listening position and do the math (or throw it in a SPL calculator). Then go a tad bit higher than that to compensate for inaccuracies in manufacturer statements about power (amplifier) and sensitivity (speakers). Done.

 

[fpitas]

Use the calculator:

Crown Audio - Professional Power Amplifiers | English (US)

www.crownaudio.com

How Much | Crown Audio - Professional Power Amplifiers | English

www.crownaudio.com

 

[RayDunzl]

My impression of speakers (not amplifiers) "coming to life" occurs when they receive more clean power, not at some ratio of output level:max output level.

It would make a somewhat expensive experiment...

Have your friend bring one over.

My disclaimer would be I prefer overpower to underpower, but I get loud on Beer Saturdays if Audio Buddy comes by, and he expects it..

 

[Waxx]

A lot depends on what kind of amps and drivers you are using. For most modern amps (class AB or D) the crown calculator is what you need to know the needed power for the most undistorted sound. So in the philosophy of this site and most of it's members, you need a lot of power for the lowest distortion. And that crown calculator mentioned above gives you the right info to get the right power for that.

WIth tube amps, the distortion is a part of the sound and harmonic, and there often much less power is needed for the typical sound you want. Class A depends, but mostly is like tube amps. Distortion is not bad with those, it's the colouration wherefor you bought the amp normally (or otherwise you're fooled). With those and high sensitive speakers, you can get the good sound with a tube amp of a few watt also (if you like tube colouration). S(ingle) E(nded) T(riode) amps like those with the 2A3 or 300B tube work on that principle. They only give a few watt, but their (high and harmonic) distortion sounds good to many ears and that is why people, even knowledgable people, buy and use those. It's not technically the best sound and not true to the source, but it's something a lot of the listeners want, and a lot of others (like here on this site) hate. But the same power on the same speakers with class D and most class AB transistor (or IC) amps will sound like shit due to the high distortion that is not harmonic.

You also got to look how loud you want to play. It's not because your speaker are rated 250w and get a sensivity of 95dB that you need 250w for close listening only. You will probally not even use a watt at normal listening levels (60-85dB) at 1m or less. So you can get away with much less watt, even with class D amps and the chase for absolute clean neutral sound in mind...

Keep also in mind that quiet a few (mostly pro-audio) speaker drivers are not build to play on low volume. Especially the big woofers may need a few watt before the cone starts moving like it should. This is due to a heavy (damped) cone and not enough force from the magnet to drive them on low power. (MMS & QMS vs BL in T/S terms). So not enough (milli)wattt from the amp may cause that the speaker does not sound good on low volume like it does on higher volume.

 

[djtetei]

Personally, I study the technical specifications of the speakers and the amplifier, take note of the continous power rating of the speakers and amplifier at the nominal impedance, consult with the equipment manufacturers and, finally choose the amplifier able to provide the +3 dB to +6 dB of headroom over the speakers continuous power rating.
Additionally, I always use a good quality mixer with accurate level meters in front of the amplifiers, to be able to control the signal level of multiple sound sources.
Know the nominal level and the maximum output level of the mixer, which may be +18 dBU, +20 dBU or +24 dBU.
The clip level of the mixing console is, usually, marked at 6 dB over the last yellow/amber leds on the level meters.
If the mixer has a nominal level of +4 dBU (0 dB mark on the level meters) and a maximum output level of +20 dBU (+16 dB red led on the level meters), I have 16 dB of additional dynamic range above the nominal level.
I intend to use the maximum dynamic range of the mixer and to ensure the best signal to noise ratio in the system, before the signal is sent to the amplifier. Therefore, I set the channel input gain to hit the 0 dB mark on the meters, then I raise the channel fader or the master output fader fully up (+10 dB), to hit the last yellow/amber leds on the meters (+10 dB), just below the clip LEDs. This offers me 6 dB of headroom before clipping the mixer output.
On the amplifier side, set the input sensitivity switch to 1.4 V RMS to match the mixer's nominal level and adjust the sensitivity controls to -10 dB attenuation for rated continous power output. At this point, the continous power output of the amplifier is about 1 dB below its maximum power output.
The above procedure it is based on the assumption that the loudspeakers continous power rating are matched with the amplifier continous power rating.
If a compressor/limiter is used between the mixer and the amplifier, the mixer output level can be increased to its maximum level (+20 dBU) and the limiter threshold should be set at the point where it begins to catch the signal peaks, with an additional 3 dB of attenuation, for safety.
If the speakers continous power rating is lower than the amplifier continous power rating, lower the amplifier input sensitivity controls or the mixer master output level according to the power you need for the loudspeakers and allow for about 1 dB of headroom also for the speakers.