Can "Digital" damage my gear?


Faulty (or malicious) CD/CD-R or digital download can contain large levels of high frequencies outside of hearing range - for instance 20kHz. Such frequency at full power will overheat tweeter and most likely damage output Zobel network in my class D amplifier. Stereophile Test CD contains such tracks and warns against playing them at full loudness. My DAC will mute anything other than valid S/PDIF but will play any frequency at any level.

What do you think? Can bad or malicious recording from CD/CD-R or server damage my speakers or amp. Is there a way to prevent it?
128x128kijanki
Software engineer, I work with, says that Fourier analysis of such size files will take forever. He participates in SETI program and does analysis of small files on his computer. Ideal would be small crude scanner program that looks for high amplitudes above 2kHz.

Kijanki -- Although as you realize there is a learning curve and familiarization process involved in using an audio editing program, once you attained sufficient familiarization, doing what you describe would be trivially easy with Sound Forge (and possibly with the less expensive or free audio editing programs as well).

All you would have to do is to spend a few minutes setting up a preset in its equalizer function, that would sharply roll off everything below 2kHz, and then set up a preset in its "find" function to find everything above an amplitude that you specify.

Once you had those presets in place, you would copy the file you wanted to check to a separate folder, and open the copy with Sound Forge (that avoids the risk of accidentally modifying your original). Then all it would take would be a few clicks to call up the two presets, and voila! The processing time required by a reasonably powerful, fairly recent pc running Sound Forge would be a few seconds at most.

If you want to pursue this approach, I'd suggest starting with the free audio editing program Audacity (easily findable on the web). I haven't used it, but conceivably it might be able to provide similar functionality.

Regards,
-- Al
Al - that sounds doable but now I started worrying about viruses. Main household computers will become servers for music. It is already happening. I'm afraid that eventually somebody will get an idea to write virus that will destroy tweeters or amps (as they wrote virus overheating Pentium processor). Separate computer not connected to internet might be better.
- that's exactly what people said about computer viruses at the beginning.
I've been involved with computers since the early 1980s. I don't ever recall such a statement by anyone. Viruses have always been a serious issue with networked computers from the beginning and that risk has grown with the internet putting more and more systems on open networks.

I've still not seen nor heard of any issue with recorded music in this fashion.

As for your concern over internet soundbites, perhaps that is a greater risk than ripped music but it also means it is far less convenient to scan prior to listening. If you're at a web site and cannot listen to a 10 or 20 second clip until after scanning you've lost a lot of ease of use and functionality.

If this is a concern, you could use a dedicated music server that doesn't do other computer duties. I do this and have no urge to use my main stereo for playing internet soundbites.

I gather this is just an issue of risk prioritization. But note that you were unable to give an example of a piece of stereo equipment - tweeter or otherwise - damaged by digital music and can only discuss it in terms of a theoretical exposure. Perhaps you are just more prescient than I, but at my house I think the bigger exposure is the dog chasing the cat and knocking something over.... ;-)
Mstll - I wouldn't ask the question if I could give an example. In class D amp it will destroy amp - just look at any Icepower datasheet.

Separate computer is good idea if you can afford it. Computer infected by virus might play destructive file without you knowing it. They did it to overheat Pentium and I suspect it will be done for audio. Chances are small but repair cost is high.

As for viruses being serious issue from the beginning (being treated seriously) - you must be kidding? People didn't want to use antivirus programs (initially free) and many don't use it still. Firewall was unheard of concept (until 1988) and not present in Windows 3.1/95/98. First IBMs went on sale around 1981 but first Norton anivirus, as well as firewall appeared around 1992 because of damages that viruses did and not before (remember Lehigh or Jerusalem viruses affecting .com files or Brain virus affecting boot sector?). Networks might be different story but it took big losses to make people believe. Whole networks went down because of viruses before people got serious about it. I think that people got serious in 1999 when Melissa virus created "epidemic".

As for viruses being serious issue from the beginning (being treated seriously) - you must be kidding?
Nope, I'm not. The fact that virus attempts have escalated over the years does not mean they did not exist before.

The first version of Windows (1983) was released about 10 years before the internet became open to the public. It took the commercialization of the internet to give the viruses, worms, trojans and all that a chance to go big time. The fact was Microsoft valued ease-of-use for non-technical consumers more than they valued security.

However, these malicious files work by targeting the operating system and programs. The vast majority of them have targeted Microsoft products. Music files don't do that. There is also the lack of a universal target. What corrupts an iTunes player won't work on a Windows Media Player. You've got a variety of software players plus an array of hardware players out there. Hackers can't get their jollies with one malicious file screwing with 90% of the users as they do with MS computers.

So you're pretty much left with putting a loud noise in a song. Would a commercial label do that? Unlikely; they wouldn't want the lawsuits. So we're kind of back to the risk of music from questionable sources, such as a listener using their megabucks stereo as speakers for listening to a low-bit-rate U-Tube video.

We're back to risk analysis and prioritization. I've had my share of situations with my stereo equipment over the past 35 some-odd years including blown tweeters, damaged styluses, and other things that required repair or maintenance. You are certainly free to worry about this problem to your heart's content, but it is not prominent on my radar screen.

There was an asteroid (2009 DD45) that just missed the earth the other day if you want something big to worry about. ;-)