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Why Your Dad's 30-Year-Old Stereo Sounds Better Than Yours
asto21 writes "Cnet's Steve Guttenberg sheds light on this interesting development that over the years, actual sound quality became a secondary selling point since most people started buying their equipment either online or from big box retailers. People started caring more about the number of connections and wireless interfaces and wattage of systems. As a result, there was less money in R&D budgets to spend on advancements in sound."
Good sound quality is still out there and still being improved. Companies like NAD are still in business and still developing amazing gear.
"Have you ever thought about just turning off the TV, sitting down with your kids, and hitting them?"
Since apparently linking to the pages with the actual content in the summary is a no-no, here they are:
First, the Cnet article talking about the test that someone else did.
Next, the actual source article.
Well, the article does ... unfortunately, we have Slashdot linking to Gizmodo linking to CNet, where the actual article was:
http://news.cnet.com/8301-13645_3-20082026-47/how-can-30-year-old-receivers-sound-better-than-new-ones/?tag=mncol;txt
Build it, and they will come^Hplain.
Impedance is highly variable for most speakers and while the average impedance is listed at 4phms, it will often dip down to 2 or 3 ohms near the lower end.
There is no substitute for mass. (this is a favorite saying of mine)
Q: Why does your Dad's stereo sound better?
A: Op-Aps and cost-cutting.
You can't tow a boat with a Prius, and you can't expect a bunch of ICs and cheap 50 cent components to properly amplify anything for any reasonable amount of time or at a decent volume. If your amplifier doesn't weigh on the order of your dad's old one, you're not going to get the same sound out of it. Everything about amplification and electronic theory was known and done as of about thirty years ago. There is no magic. Only trickery and marketing.
The biggest lie of them all is wattage. 95%+ of the time, they state wattage as maximum through one speaker. So that 200W 7 channel amplifier is actually only putting out about 29W to each speaker, maximum. But distortion and heat will limit you to about half of that continuously, or about 15W per channel. Given that typical speakers are about 87-89db efficient, that means that you net a pathetic 90db or so that's actually usable. While this is still quite loud, it's far below what you really need for good home theater. Most people try to compensate for this by turning up the volume, but all that really does is bombard them with more and more high frequency sound since the bass long ago disappeared. This, naturally, leads to listening fatigue and hearing damage. The older amplifiers were rated as typically 100W per channel or more, and could deliver about 80% of their maximum rated volume without any problems. They did not get weak under heavy loads or strong bass, either.
This also applies to the most critical aspect of the system, the speakers. You simply cannot convey a full sound through miserable little 5 or 6 inch speakers. And a single subwoofer is a poor way to fill in for a weak mid-range and missing low-end. You don't play your guitar or bass through a 6 inch cabinet, but somehow people forgot to use common sense. So often you have a decent amplifier hooked up to junk speakers. You "father's system", I bet, has 8 or even 12 inch woofers in the main speakers, as this was common back in the 70s and 80s. In order to produce a convincing sound, you need to move air and create enough sound pressure. Or else it sounds like your neighbor's stereo does from down the street - tinny and distant.
But all of this is truly ancient news. People were discussing this twenty years ago or more online.
There is no substitute for mass.
This is generally true, however with switching supplies and Class-D amplifiers, really good sound is available from feather-weight amps. A LOT of attention needs to be paid to filtering, switching frequencies, fast diodes, shielding, load compatibility, etc, but assuming these issues are competently addressed, a light-weight amp can sound good and have plenty of grunt.
Q: Why does your Dad's stereo sound better?
A: Op-Aps and cost-cutting.
Cost cutting yes, op amps not necessarily. With a correctly chosen op amp in a correctly designed circuit, sound as good as or better than discrete designs is possible. Unfortunately, too many designers assume that a TL071 or an NE5534 in a garden variety topology is sufficient. It isn't.
The biggest lie of them all is wattage.
I'd say that the biggest lie is THD. Not that the spec'd THD figure is incorrect, (that's another issue), but that THD is a poor predictor of sound quality. Distortion figures of 0.1% or more are appalling to the average audio engineer; however if the harmonic content is mostly low-order and mostly even-order, an amp with this much distortion, or even more, can sound wonderful. On the other hand, an amplifier can have a 0.001% distortion spec and sound truly awful. This happens when a circuit that is inherently highly non-linear is given a low THD spec by using copious amounts of negative feedback. This causes lots of high-order odd harmonics, which are subjectively much, much more objectionable; the THD spec is good, but the amp sounds harsh and sterile. Even in the 1940's this problem was recognized, and highly respected audio engineers suggested that THD be calculated by weighting harmonics according to the square, or even the cube, of their order. These engineers were ignored by an industry that was increasingly driven by specsmanship and cost-cutting rather than by sound quality.
You simply cannot convey a full sound through miserable little 5 or 6 inch speakers.
If you're talking about overall speaker size then you are correct, however if you're talking about just the driver size then there's an experience you've missed. A good full-range driver in the 4-to-6 inch range, (an expensive Lowther driver, or even a fairly cheap Fostex), in a nice big cabinet that horn-loads the back of the speaker, can produce surprising amounts of bass and an overall magical sound.
'The Economy' is a giant Ponzi scheme whose most pitiable suckers are the youngest among us and the yet-unborn.