Asheville’s Home Theater and Audio specialists present Cane Creek AV and Paul McGowan – PS Audio, Intl.

How much is too much?
There is a fairly common misconception I run into when speaking with customers, particularly at shows.
“Is my amp going to draw too much power from the wall or a Power Plant?” It’s a good question and it’s easy to get confused about it.
Let’s imagine you have a 500 watt per channel power amp. Well, naturally you’d figure it might take up to 1000 watts from the wall. Right? And if you someday upgraded your power amp to one that has a whopping 800 watts per channel, that figure could go up to 1600 watts! That’s a lot of power.
So how much are you actually using, and what’s the limiting factor? It all depends on your speakers. A 100 watt power amplifier will output the same wattage as an 800 watt amplifier when powering the same speakers and playing the same music. So you could connect a zillion watt amp up to your speakers and still, they’d just hum along taking whatever they needed and nothing more.
So the first thing I ask people when they question me on a Power Plant’s ability to handle a big amplifier’s load is “what’s the efficiency of your loudspeakers?” A low efficiency number, somewhere down in the 85 to to 88dB range, is going to take a lot more power from an amplifier than a 90dB or even a higher 92dB efficient speaker. The efficiency rating on your loudspeakers, and the type of music you listen to, will determine how much power your amplifier outputs.
So why do we bother with bigger amps? Because the worst thing you can do is under power your speakers or, more realistically, get the amplifier’s output close to its maximum rating. Amps should work at a comfortable level to them. a 100 watt amp straining to put out close to its maximum won’t sound as good as the exact same wattage output from a much larger amplifier.
It’s called headroom, a term I am sure you’re familiar with. More is better, but it doesn’t take more juice out of the wall of the Power Plant to have it.

Asheville’s Home Theater and Audio specialists present Cane Creek AV and Paul McGowan – PS Audio, Intl.

Generating depth
One of the test tracks I am using to test all the DirectStreams shipping out today has a lot of depth. It’s important that I check this sound quality area because it’s one easy way to tell if everything’s working correctly.
But I can’t help wondering how the recording engineer achieved such depth.
Depth is typically achieved by moving the performer away from the microphone. The greater the distance from the microphone, the more depth we would hear. Depth comes from behind the loudspeaker pair, moving away from the listener and the speakers. To help visualize this, think of your loudspeakers as a pair of microphones set up on a stage, spread apart the same distance as we will eventually have our loudspeakers setup to reproduce left and right. The microphones are pointing towards the musicians on that stage to record their performance. You are in the audience, which puts our imaginary microphones approximately in the middle of our room, halfway between you and the musicians, pointing towards the musicians.
When it comes time to playback the recording, we remove the microphones and replace them with loudspeakers. Only this time, the loudspeakers are pointing away from the musicians and facing you, in the audience. If we did a good job, the loudspeakers should vanish and the sound should come from behind them as if the musicians were still on stage playing. Again, this is why proper imaging of your system should always come from behind the loudspeaker pair and that loudspeaker pair should be away from the rear wall and provide enough room for the soundstage to exist.
But what happens if there is an electronic pickup that is not a microphone? For example, an electric guitar, piano or synthesizer. How does the recording engineer provide a sense of depth when there’s no proximity to a microphone? The most obvious way is level; the lower the level, the farther back the sound will probably appear. I would also imagine adding reverb would help as well, as this would simulate the increased room reflections the microphones would pickup in the first example.
It’s an interesting question and one I ponder.