Stop Using Music to Test Subwoofers!
The common advice when shopping for speakers is to test them using music. Heck, we give the same advice. So it makes sense to many that you should use music to test out subwoofers. But what music will give a sub a good workout? I’m sure there are lots of specific songs out there but if you are looking for a genre, rap is where it is at. So, is this good advice? Should you use music to test subwoofers? I think our position is pretty obvious at this point.
Why Music and Subwoofers Don’t Mix
We’ve made the case that you need a subwoofer (or two) to fully experience music. We stand by that assertion. But there is surprisingly little musical content for subwoofers to play. Enough that you need one to fully hear every note in every song, but not so much that your sub is really put to task. Most of the lowest notes that musical instruments can make aren’t really much lower than 40Hz. The ones that are come from synthesizers and pipe organs.
Your subwoofer operates from 20Hz up to just north of 80Hz in most cases (depending on how you set your crossover). If most music has very little content south of 40Hz, you can’t really trust that your subwoofer is playing at all in those frequencies. Since these very low notes are exceptionally hard to hear and can have a huge impact on how your subwoofer sounds, it is important to hear your sub in action at all frequencies.
But I’ve Got This One Song that Slaps!
Yes, we’ve all heard a song with some insane bass notes. They aren’t hard to find (especially if you like rap). But the key here is notes. They’ll have one or two or maybe half a dozen notes that are low. That’s great. Using that music to test your subwoofer will test out how it plays those notes. But not all the rest.
Even if you find a song that has some sort of run in the low bass, it is unlikely to go low enough. Remember, the lowest bass is very hard to hear. You may feel it, but you are not really hearing it. Why would any artist put such notes into their song knowing that many people will be using headphones or car stereos that can’t reproduce those notes? They won’t (and don’t)! Yes, you have a song with low notes, but that’s not enough.
Sweeps are the Answer
Unfortunately, the only way to really test out a subwoofer is by playing sweeps. A sweep is very much like running your finger down the keyboard of a piano so that you can hear all the notes in order. With subwoofers, you need a sweep so that you can hear how each note interacts with your room. You can’t do that with music that only contains a handful of notes.
As the sweep plays, you should experience the volume of the subwoofer increasing and decreasing. This is normal. This is what happens when very long bass waves interact with each other as they bounce around your room. What you are really listening for is very large volume drops. If your prospective subwoofer seems to disappear for part of the sweep, then you have a problem. If it is at the lowest frequencies, it could be that the subwoofer just can’t play low enough. If it is in the middle, then you’ll need to address the acoustics of the room with bass traps. This information is invaluable and can only be gained by listening to sweeps.
Of course, after you are done with the sweeps, play whatever you like. That’s the fun part!