Watts! How many do we need?

My Speakers are Harbeth C7ES-XD at 86db sensitivity. They are rated at up to 150 watts. Their impedance is 6 ohms with the lowest at 5.8 ohms. So an easy drive. But I've been told they like power. The Accuphase P4600 is rated at 150 watts per channel at 8 ohms and 300 watts at 4 ohms and the amp is probably capable of delivering 225 watts per channel at 6 ohms. I have them positioned in a well furnished carpeted room about 7 feet apart and 30" out from the front wall very slightly toed in. I sit about 8-9 ft from them. I have the meters set to freeze at the highest output and they have never exceeded 1 watt so far. Now I don't listen at some of the levels some of you do. My sound pressure meter never exceeds 75 db and is mostly between 60 and 70 db. If the meters are accurate I'm in Class A all the time and the amp is not breaking a sweat.

atmasphere wrote:

If you need over 100 Watts to make your speaker really sing, you have a problem-the speaker might be criminally inefficient unless you are in a very large room.

I would agree, but practically speaking it’s hardly as much low efficiency as it is a difficult load caused by the passive crossover. A lot of amp power can be wasted here, sometimes forcing even several hundred watt and PSU-sturdy amps to their knees. Making matters worse though we mostly see the combination of low efficiency and difficult load, whereas conversely the combo of high efficiency and easy load - not least via active configuration and higher impedance - will make a given amp sound substantially better for a given SPL.

Low eff. in addition to difficult load is a sonic bottleneck that to some can’t be ignored, while to others it’s the only thing they know. To my ears it’s not unlike listening to speakers covered by a blanket - the music just never really frees.

The more power you need, quite often the harder it is for the amplifier to sound like real music. Most higher powered amps I’ve seen simply don’t, although they are pretty good at sounding like electronics.

That’s a popular notion, and I assume not without merit, but as you implicitly indicate there are exceptions. Both due to the specific amplifier design and because my actively configured high efficiency speakers - i.e.: high eff. in the entire frequency range, incl. the subs - present such an easy load to the 3 similar amps, each of them frequency limited to their respective driver segments and independent of the others’ load, the amps are given ideal working conditions and seeing their potential more or less maxed out.

To explain: a 625W amp (8 ohms) given only a ~620Hz on up signal driving a 111dB horn/compression driver combo coupled directly to its terminals with a close to pure ohm load will be cruising along with very low distortion - even at deafening levels. If it’s already a good design, and it is, it will see its performance envelope fulfilled in a way no passive, low efficiency speaker iteration with a single amp covering the entire frequency range can equal.

As others have said, meters, even digital ones, are s-l-o-w. Even on digital recorders, the meters are too slow to see "transient peaks", which is one reason manufactures recommend recording with the "peaks you do see" topping out at -12dB. This allows enough headroom for those transients such that no clipping or compression takes place.

So yes, having more watts can be a good thing - as long as the slew rate of the amp is capable of keeping up with the music and offering those louder transients that might last less than 1/100th of a second, such that the music sounds as "real" as possible.

So, when you are looking at meters, you are more or less looking at what the continuous output power is, averaged over a significant fraction of a second, therefore yes, you will see that most of the time the amp is putting out 1W to 10W at even "loud" volumes. 

Most of the time, I'm using 1-2w listing to the radio. If I want to rock out, or make the house vibrate I use around 50-60w this is out of a 200w amp. At 100db (system can do well over 100db without clipping) at 60w, there will be 100+w peaks.

Since it takes double the power to produce 3db gain, it's good to have all the power, and use it when you want it. Generally a 200w amp will sound better at 50w, then a 50w amp at 50w. Plus staying that far under the amp's peak power produces much cleaner power to the speakers. 

Most of the time, we will all be happy with a 20w amp, but I would never buy anything under 100w

Anyone that listen at 113-115db are either def or stupid, or if doing it routinely maybe both?

If you are not def, is it then something you aspirer to be ?

Why would a music lover try to intentionally destroy one’s hearing?

As older we get our hearing for most people deteriorate and unfortunately for many it hinders their ability to function 100% in social gatherings and for some people they choose to redraw a bit from social life.

Also as it is now, there is nothing you can do if getting tinnitus which even is a much bigger problem.

i worry about the younger generation that blast music into their ear canal’s with in-ear headphones, I am guessing that most of them will have big hearing/tinnitus problems before they are 50!

Don’t get out much, do ya? Lots of folk go to a monthly concert. And they are played in the 113-115 range. Many times, much more than that. You think all those thousands of listeners at the live performances are going deaf? It better hurry up if it’s going to affect me. I’m almost 70 and have been around loud race cars my entire life.... (And a dash of music). You sound boring! But enjoy life however you want it, I know I have enjoyed the heck out of mine.

https://youtu.be/q_-Z0ZVXWZg

https://youtu.be/6O9r_1gnpg0