SIGNALS

Well, actually, that title should be Bass Cows from Mars! But in any case, in the long tradition of weird ways to show off your system's bass response, NASA has kindly obliged us with an especially weird way.

The opening pedal tone from Also Sprach Zarathustra, the cannon shots in the 1812 Overture, the tympani in "Dies irae" of the Berlioz Requiem (also a good way to demo quad) — pick your favorite — there are innumerable recordings out there used to show just how low you can go. My personal favorite, Bass Cows from Hell! , was a CD from Soundstream that offered deep tracks such as "Bass Cheeks," "Spank the Monkey," and the immortal "Bowling for Food Stamps."

The newest way to boast about your bass comes from the surface of Mars. Insight is the latest spacecraft to land on Mars, touching down on November 26. Unlike the rovers, Insight will be stationary; its two-year mission is to study the history and structure of the planet's mantle and crust.

One of its primary instruments is a seismometer that will be used to study marsquakes and other seismic activity as well as atmospheric waves and tidal forces from Mars' moon, Phobos, up to a frequency of 50 Hz. On December 1, this instrument (essentially acting as a microphone) sensed vibrations on the lander's solar panels, vibrations caused by a Martian breeze, estimated blowing between 10 to 15 mph, rippling across the panels. The frequencies of these vibrations lie at the bottom of our audible spectrum and thus provide an ideal way to test your playback system's bass response.

Check out this NASA video. The sound of the Martian wind is plainly audible, but only if your playback system has the bass response to reproduce it. If that's too low for you, NASA gives you another shot at it, pitching-shifting it up two octaves. NASA also throws in a recording from an air-pressure sensor that also detects the Martian wind; this instrument only detects subsonic frequencies, so to make it audible, NASA speeds it up 100x. It is interesting to note that the Martian atmosphere is very thin — about 1% of earth's density — and this makes it difficult for high frequencies to travel through the atmosphere. Mars is a bass-heavy planet. Who knew?

Now, let's think about this. Listen for a moment. You are essentially hearing the sound of wind. On Mars. Holy Moly! How cool is that? And when your kids or grand kids are actually on Mars, that is essentially the sound they will hear, being conveyed through speakers in their helmets. No human will ever (hopefully) hear the sound of the wind on Mars directly with their ears. This recording, right now, is about as close as we'll ever get to hearing the Mars equivalent of a sound we take for granted on Earth.

And, finally, what on earth do cows have to do with bass response? Well, what sound does a cow make? The uninitiated might think that cows moo. But in fact, cows low. I'm not making that up.