Receivers vs. HTIB's

The subject at hand is one that is very confusing, so I will try to keep it as simple as possible. I still want you to understand the differences, so if you have any questions just let me know.

Most have been confused how a $1000 receiver can do 700 watts but a $500 HTIB can somehow do 1000+ watts. There is actually a lot of math involved in it but I’ll keep this as short and sweet as possible. I have been researching this on and off for the last 2 weeks so I can make it easy to understand and accurate.

There are two quick ways to tell the truth about power ratings:

1) What is the distortion rating?

2) Power Consumption: How many amps or watts does the amplifier actually pull?

With either of these two pieces of information, we can tell who is making up numbers and who is telling the truth. Let’s look at them individually. For both of the examples below we will use the Panasonic 1250W Home Theater in a box (SC-BT300) and the Denon AVR 790 receiver.

Distortion

The industry standard for amplified sound distortion is 0.1% (1/10th of a percent). Anything more than this is considered unacceptable. The reason this is important is you can push an amplifier beyond what its physically capable to produce a high wattage number, however the high amount of distortion makes it pointless. Let’s compare our two examples:

The Denon AVR790 (that is rated at 660 total watts) runs at 0.08% distortion which is better than the industry standard. Now lets look at the Panasonic SC-BT300.

The Panasonic SC-BT300 produces 1250 watts at 10% distortion (yes ten percent, that’s not missing a decimal). What does this mean? Well, it means it produces sound 100 times more distorted than the industry average AND 125 times more distorted than the Denon receiver. If you go to Panasonic’s website, you will see they also provide the SC-BT300 a wattage rating of 650 watts at 1% distortion. That’s definitely better, but still 10 times more distortion than is considered acceptable. Basically, Panasonic can make the unit product twice the wattage if it increase the distortion by 10 fold. So at the industry standard of 0.1% the Panasonic SC-BT300 would produce 300 watts. The system powers 7 speakers and a subwoofer so 300 watts / 8 speakers = 37 watts per channel. Not very impressive anymore is it?

Well, theres one more problem:

Power Consumption

A device cannot produce more power than it pulls. If you flip the Panasonic receiver around you’ll notice on the back it says “120 watts 120 volts”. A 1 amp device pulls 120 watts at 120 volts. So the Panasonic SC-BT300 pulls 1 amp. So we just found that the Panasonic SC-BT300 should produce 300 watts at 0.1% distortion. But heres the problem: it only pulls 120 watts. This means it can only PRODUCE 120 watts. Yes, that 1250 watt HTIB is now down to 120 watts. This same system also has a built in blu-ray player (my upconvert dvd player says it pulls 12 watts) which lets say pulls 20 watts. So now that 1250 watt sound system is down to 100 watts. Lets look at how that works with 8 speakers: 100 watts / 8 speakers = 12.5 watts per channel.

Let’s compare this so the Denon 790. The Denon says it pulls 5.5 amps, if we calculate that (amps x volts = watts) then we get 5.5 x 120 = 660 watts. The Denon receiver actually produces the watts advertised! Thus the Denon can produce 90 watts per channel.

Typically it takes twice the wattage to produce twice the loudness (an increase in 10 decibels) thus the Denon Receiver will produce clear sound 3 times as loud as the Panasonic HTIB could ever hope to.

Next week we will look at multi-zones and speaker selectors so we can understand how to use those properly.

As always, any questions or comments, just let me know.