Lies Damn Lies and Amplifier Specifications
by Paul Sonoda
For you film geeks, there was a movie in 1990 called “Crazy People”. It starred Dudley Moore and Darrel Hannah. It’s about a New York advertiser who goes crazy about how he has to fabricate half truths about products to sell them. In retaliation, he freaks out and creates the ad, “Volvos, Yes they are boxy, but they’re safe”. The irony and moral of the movie is that Dudley’s character rejected the common marketing practice of telling lies and half truths and became successful by marketing the truth.
The sad reality is that many car audio companies lie or stretch the truth. Ok, maybe that’s unfair. Let’s just say some car audio companies knowingly mislead the consumer. Why do they do this? The common answer is that their competitors do the same so they have to resort to these tactics to remain competitive. Yes, that is justifying bad behavior by pointing to other bad behavior. Regardless of the intent, all lies (misrepresented amplifier specs) are constructed to perform a single function: mislead the consumer. So where am I going with this?
back 
topDoes it pass the smell test?
Let’s say you are in the market for a car audio amplifier. Awesome! You pick up your Sunday paper and look in the ads for great deals. There it is: an amplifier with 1,000 watts of power for ninety-nine dollars. Does it sound too good to be true? It probably is, but how can you tell? Don’t worry. We have put together a guide for you to navigate the accuracy of your amplifier specs.
Look for Units
One of the most common deceptive ways to mislead the consumer is to play with the units. For example, my car goes 0 to 60 in 4 seconds. Sure it sounds fast. But the real question you should ask your self is …60 what. Is it like feet, inches, or kilometers? In the world of car audio, units are everything. If the amplifier has a bold number of 1100 printed on it, does it mean this amplifier will make 1100 watts? It could mean this amplifier has one channel that outputs 100 watts. Heck, it even could be the model number of the darn thing. Get the picture? Without units, the spec is meaningless and should be ignored.
Beware of Misleading Specifications
So you get a power spec with units like this 500 Watts. Is that good? Not necessarily. Quite often we see specs that tout “Max”, “Dynamic” or “Peak” power ratings. When you see power specs ask your self these questions: At what distortion, at what frequency and is it peak or RMS power. All these specs tell you are that the manufacturers were able to get these measurements out of the amplifiers. It does not tell you how they did it.
Using our vehicle performance analogy, you could mislead consumers by stating that your car accelerates 0 to 60 MPH in 4 seconds. You just forgot to mention that it was achieved falling off a cliff. Sound ridiculous? That is exactly what some amplifier manufacturers are asking you to swallow with their “Peak” and “Max” power ratings. Without relevance, the spec is meaningless and potentially misleading.
The Best Light Gambit
Ever see a picture of a car that looked great only to find when you see the car in person it did not look as good? This is what I like to call the “Best Light Gambit”. With amplifiers, there are many ways hide its shortcomings in the shadows. For example you might see a subwoofer amplifier rated at 600 Watts RMS =1% THD + Noise. What you did not know was the amplifier was measured at 16 Vdc at 10kHz. Not really the operational range of a subwoofer. At 50Hz and 14.4Vdc, the amplifier produced a respectable 500 Watts RMS. So is this a 500 or 600 Watt amp? To many companies, it’s a 600 Watts amp. Is this making any sense?
Anatomy of a good power rating
For an amplifier spec to be meaningful, you need to know what kind of power, what bandwidth and at what distortion level. A relevant power spec would look something like this: 500Watts RMS x 1 from 20Hz to 20 kHz =1% THD + Noise at 14.4 Vdc. Respectable amplifier manufacturers will have no problem specifying all the relevant “test conditions” observed while measuring the amplifier’s power output. Fewer details provided can mean that the manufacturer is trying to hide something. It is your job as retailers to know the facts about your products and competitive amplifiers.
What Specs To Look For in an Amplifier
So far, all we have focused on was the amplifiers power output capability. There are other aspects about the performance of the amplifier that is also important. Frequency Response, the span of frequencies an amplifier can produce, should be reported with a range followed by a tolerance (20Hz to 20kHz ±3dB). Damping factor is a measure of the amplifiers ability to control the motion of a speaker. The proper measurement standard for damping factor is complicated but is expressed as a number (without units) that is a ratio of the internal impedance of an amplifier compared to the impedance of an amplifier with a speaker connected. Damping measurements are usually referenced at a particular frequency 200Hz. Signal to noise ratio is a measure of the quietness of the amplifier. It is typically expressed as in dBA (the “A” weighted reference scale for sonic measurements). Finally, Channel Separation is the amount of isolation between channels in a multi-channel amplifier (an amplifier with two or more channels of amplification) It is also commonly expressed in dBA.
Light at the End of the Tunnel
It is obvious that things have gotten out of control. Fortunately, the CEA (Consumer Electronics Association) realizes this and has developed the CEA-2006 standards for automotive amplification. The CEA standard establishes criteria for measuring the rated power and signal to noise ratio of an amplifier. In order to carry the CEA-2006 Certification logo, the amplifier must have the primary standard of rated amplifier power and signal to noise ratio. Additionally, secondary specifications are also defined and must be adhered to use the CEA-2006 logo. The purpose of this standard is to create a standard reference where amplifiers from all the manufacturers can be compared fairly. Until all the amplifier manufacturers adopt, embrace and follow the CEA-2006 standard and ideology, audiogearrevies.com will continue to protect and inform the consumer by reporting the lies damn lies and amplifier specifications.
Specs
without units
