How low can you go? Pretty darn low if you use a subharmonic generator (aka “subharmonic synthesizer”) plug-in. Such plug-ins produce undertones, which are a type of harmonics, but instead of being above the fundamental frequency of a note, they’re an octave or two below it.
With a subharmonic generator, you can extend the bottom end in a way that fattens up the sound of sub bass. You’ll be able to hear the results most clearly if you’re listening to a speaker system with a subwoofer. However, you can also hear it through a good pair of headphones or studio monitors with 8” or 10” drivers that can reproduce below 45Hz or so.
In this excerpt from “Mick Guzauski Mixing Jamiroquai,” Mick uses the Avid plug-in Pro Subharmonic plug-in to beef up a sampled kick drum.
WAY DOWN LOW
Like most subharmonic synthesis plugs, Avid Pro Subharmonic lets you dial in more than one undertone and mix them in with the dry signal. Mick sets the Mix (wet/dry) control at only 7%, fattening the kick in a subtle fashion. He then plays it with the Mix turned up to 36% so that you can really hear what it’s doing to the sound.
Avid’s Pro Subharmonic plug-in, the same one used by Guzauski to reinforce the kick drum in his mix of “Vitamin” by Jamiroquai.
Pro Subharmonic is a plug-in that is not part of Pro Tools’ included plug-in collection, you must purchase it separately. Many other software developers also offer subharmonic generator plug-ins. Some examples are the recently released Waves Submarine plug-in, Joey Sturgis Tones Sub Destroyer and Brainworx bx subsynth, which is also available in a UAD version that’s simply called “bx subsynth.” For the examples in this article, we’ll be using the UAD version.
You have to be careful with subharmonic synthesizer because if you apply the undertones too heavily, you can create a low-frequency mess at the bottom of your mix. If your monitors only go down to the 50Hz area, you’ll probably need to use a quality pair of headphones to be able to hear those lower frequencies when applying the effect and checking your mix. You certainly don’t want to add a bunch of low-end information that you don’t even know is there. It could create an unpleasant surprise when your music gets played on a system with a subwoofer or large speakers.
Waves Submarine is a recently released subharmonic generator plug-in.
SUBBING OUT
Subharmonic generators are particularly useful for beefing up low-frequency elements such as kick and bass. You can also apply them to instruments that are heavy in the lower midrange, such as snare or male vocal. Some people even use them on the master bus of a mix.
UAD’s bx subsynth, like Pro Subharmonic, offers a bunch of useful features. It gives you three frequency zones in which it produces subharmonics based on audio one octave above. The 24-36Hz band creates undertones from source audio in the 48-72Hz range, the 36 to 56Hz band from the 72-112Hz range, and the 56-80Hz band from the 112-160Hz range.
For each of those bands, you get a separate level-control knob. There’s also a master Subharmonics knob that governs the overall output of the subharmonic signal. Like on the Avid plug-in, and most subharmonic generators, you get a Mix control for blending processed and unprocessed audio.
With bx subsynth, you can also add saturation and apply filtering. For the latter, you get a useful control called Tight Punch, which uses a high-pass filter to create a resonant peak at the selected frequency. It also rolls off the frequencies below the one you chose. True to its name, it makes the output of the effect more punchy.
KICKING IT
Let’s check out more some examples of a subharmonic synthesizer in action. (If you can, listen to the examples on studio headphones or a monitor setup with a sub or large drivers.)
Ex 1: You’ll hear eight measures of the kick and bass parts from an electronic pop mix. The first four measures have no subharmonic synthesizer, but the second four do. Starting at measure 5, you’ll hear how much beefier it gets. The bass is a doubled part consisting of both a synth bass and a Fender P-Bass. The two basses were submixed onto an aux track. Separate instances of UAD’s bx sub synth were applied to the bass aux and to the kick drum.
Ex. 2: This time, you’ll hear the example in the context of the rest of the instruments. Again, the subharmonic synthesizer plug-ins were bypassed for the first four measures and come in on measure 5.
A screenshot of the instance of bx subsynth that was used on the kick drum. You’ll see that the subharmonics were all coming from the higher two bands, 56-80Hz and 35-56Hz. The wet/dry mix is pretty high, at 35%. This is a much less subtle application than Mick used in the excerpt. Notice also that the Tight Punch filter is engaged at 40Hz, which tightens and focuses it a little.
The setting for the bass aux has its greatest subharmonic boost in the middle band, the 36-56Hz range. The Tight Punch filter was again used, although at a lower frequency, 34 Hz. If you heard the bass get wider when the plug-in was engaged, that’s because the Stereo Width parameter, which uses M/S processing, was set to 237% to give the bass a full, stereo sound.
Ex. 3 In this last example, the subsonic generator was taken off the individual bass and kick tracks and put across the master bus. It’s bypassed in measures 1-4 and engaged in 5-8.
The setting used on Example 3 adds not only subharmonic bass but some saturation to the master bus.