Like the Strat quack or the fat humbucker sound, there are numerous examples of imaginative descriptions when it comes to music. But players aren't the only ones that use lively language to describe tones in the world of music gear. Take Fender's amps for example: along with the standard volume, gain and EQ knobs, a few of their amps also feature a setting labeled "Presence." Much like the "Attack" control, the presence knob isn't named for what it technically does to your tone but for what it sounds like it's doing. In this article, we discuss what this knob actually controls, how it works and how it differs from other amp settings.
What It Does
The presence control on an amp is used to boost the upper midrange and treble frequencies in a certain way that makes a guitar's tone sound notably livelier, raspier and wilder than normal. In other words, it makes the tone more pronounced and present, especially in a mix, hence the name. This doesn't mean that the upper mid and treble frequencies become louder though as an amp's volume control affects all frequency at an even rate. The presence control also doesn't affect a guitar's tone the same way as the Mid and Treble EQ controls do either.
How It Works
But before we get deeper into how the presence control actually works, we need to lay down a few basics of amp design, namely, the preamp and poweramp stages. The preamp stage is where most of the tone shaping is done while the poweramp section provides the necessary power needed to drive the speakers and produce your desired sound level. An amp's traditional Bass, Mid and Treble controls reside in the preamp stage and, therefore, do their EQing before the signal reaches the poweramp. These controls generally attenuate frequencies, meaning they don't boost anything but rather control the amount of frequency band you want to remove from the signal.
The presence control, meanwhile, lies in the poweramp stage. Technically speaking, the presence control can be described as a "high-frequency shelving boost" control, not unlike the treble control on a traditional stereo system. Like this description suggests, the presence control does, in fact, boost part of the frequency band.
Because of the nature of how poweramps are designed and function, specifically power amp feedback, the presence control affects upper mid and high frequencies in a completely different way that than the normal tone controls found in the preamp stage. When you increase the presence control, you decrease the amount of high-frequency feedback in the poweramp. This causes the amp to distort more easily for higher notes. It also decreases the amp’s ability to accurately control the speaker cone at high frequencies. This is what allows the presence control to make an amp sound wilder and raspier in a way that the treble control knob simply can't.
Clean VS Distorted
When played through clean amp settings, dialing up the presence control simply gives your tone more upper midrange and treble. When pushing an amp into distortion, the presence control acts a bit differently. It changes the feel of the distortion and adds complexity to the sound, making the amp feel a bit unpredictable and wilder for higher notes. The presence control also varies with volume: the louder you play, the more intense and noticeable its effect becomes.
The presence control was famously featured on many of Fender's legendary "tweed" amps of the 1950s. Today, you can find this control on several of their current amps including ’59 Bassman LTD, ’57 Band-Master, Blues Deluxe Reissue, Hot Rod DeVille 212 III and 410 III, Hot Rod Deluxe III, EC Twinolux, George Benson Hot Rod Deluxe and more.
Your Turn to Sound Off!
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