Watt’s the Deal?

Here at Rewind, we’re faced with the question of “are watts important?” on a near daily basis. The short answer is, “sort of.” Seeing as I’m sure that doesn’t help one bit, I’d like to offer a more detailed response. We need to first define what a watt is. So here goes:

One watt is the rate at which work is done when an object’s velocity is held constant at one meter per second against constant opposing force of one newton.

     

Get it? Got it? Me either… In other words (and for those us who don’t have the watt named after us) a watt is a measure of work. In the case of stereo and home theater systems, the work being done is moving the drivers (tweeters, midrange, and/or woofers) back and forth inside your speakers. The power to do this work is supplied by an amplifier. This amplifier is either inside your receiver, or in its own cabinet.

If you’ve been into a stereo or home theater (HT) store, you’ve probably heard that watts matter. The higher in price you go, so go the watts. The best pieces are sometimes three or even four times more powerful – in terms of watts – than the least expensive gear. So how many watts do you need? Not as many as most of today’s equipment manufacturers would have you believe, unfortunately.

It’s no conspiracy theory, just business. Many of today’s manufacturers are owned by private corporations or private equity funds: dispassionate, financially-minded managers with a beady eye on the bottom-line. They study customers’ willingness to pay for certain packages of features, combine those results with the imperatives of their long-term technology and new-product release schedules, and design products based on these results, and the vagaries of current prices of different metals. Finally, they add in whatever cost-cutting measures they think the market will tolerate, and violá!

Most of the basics that customers require are relatively inexpensive. So manufacturers use wattage to differentiate the top of the line from the bottom. This has led to the inexorable creep of more and more watts of power packed into receivers, amplifiers, and powered subwoofers. Meanwhile, workmanship slowly creeps downward, as engineers game the measurements (distortion, for example) to create the appearance (on paper) of good sounding gear, for as little cost of goods sold as possible. After decades of this, most new equipment, and almost all of what you’ll find at a big-box store, is of low quality and FAR OVERPOWERED.

It is hard to blame the manufacturers for this trend. After all, it’s much more difficult to explain why using gold-plated contacts is better than aluminum – and even harder to get customers to pay for gold-plated when the next product on the shelf boasts so many more watts for the same price. So cost-cutting goes largely unnoticed.

One of the most common ways is to have different components share parts. For example, if two channels (or five channels) all share the same amplification components (transformers, transistors, etc…), then the amp can produce more “watts per channel” but use less copper wire. Another cost-cutting measure is to have many speakers share one crossover, which is one of the reasons for the deluge of all-in-one systems.

So the next time you’re in a big-box store, ask yourself: how do i find out which one of these receivers uses the most gold in their contacts? Or if not gold, how much do the contacts weigh? You may well find you can’t find that information. That should tell you just how powerful the concept of wattage has become, and how little you can find out about the quality of the equipment.

Also in that store, you’re likely to hear something that’s true: more wattage in general often results in better sound. But it would be more correct to say that more wattage of a given quality sounds better in general. There’s that pesky quality thing again! You see, not all wattage is created equal.

How much is enough?

So how many watts do you need for your stereo or home theater?  Well, unfortunately, it depends.  Here are the things that affect your power needs the most:

Speaker Efficiency: some speakers are very efficient, which means they make a lot of sound on only a few watts.  Other speakers need a lot of power to make the same volume of sound.  Hallmarks of efficient speakers are ports (holes) in the cabinets, large paper cones, and horn-loaded tweeters.  

Room Size: the larger your room, the more power you’ll need to fill it, all else equal.  For a room 18 feet by 18 feet, with 9-foot ceilings, you’ll want a stereo with at least 25 watts per channel with efficient speakers, or 40 watts per channel with non-efficient speakers.  Think those numbers are low? They’re not.  You simply do not need a stereo where you only turn up the volume to “3″.  Oddly, take a look around and that’s what most people have.  Interesting, no?  That 200 watt-per-channel Sony you got from the electronics store could power a P.A. for a large church…how did it end up in your living room?

Type of music: if you listen to music loud, you’ll need more power than the guy whose ears hurt at the slightest hint of decibels, obviously.  Also, rock, reggae, and rap are not only bass-driven styles of music, but listeners to these often like to boost the bass relative to the rest of the music.  If that’s you, you’ll need speakers to make the really low frequencies, and the wattage to match.  Again, for that fabled 18 x 18 – foot room, an extra 125 watts or so for bass reinforcement should be plenty.

Buy the Lowest of the High