I recently invested in a Kemper Rack, and it’s been a game-changer for my guitar setup. Having primarily used digital processors, stepping into the world of Kemper has been incredible for its versatility. However, I’m still working through some nuances, particularly regarding tone and frequency, especially when using high gain amp profiles for both rhythm and lead playing.
I’m familiar with the Fletcher Munson curve and how our perception of frequencies changes with volume. I also understand the need for a Low Pass Filter (LPF) in live sound scenarios, which I apply when going through a PA system. My research into guitar speaker cabinets indicates they typically operate in the 80Hz – 5-6kHz range. This is where my question arises: where do the higher frequencies, like 8kHz to 20kHz and beyond, come from in profiled tones if guitar speakers themselves have a limited frequency response? Is it the microphones used during profiling that capture and enhance these higher frequencies?
Currently, I run my Kemper directly into the PA at loud volumes and usually set an LPF around 6-7kHz. For studio recording, I tend to cut frequencies higher, around 10.5kHz. I’m questioning whether I should be mirroring the frequency spectrum of physical guitar speakers when setting my LPF and High Pass Filter (HPF) for live performances. Is it acceptable to cut less high-end when using the Kemper at high volumes through a PA?
While I know tone is subjective, I’m aiming to understand the technical aspects better to refine my guitar tones and make them as authentic as possible, resembling a real amp, cabinet, and microphone setup. Since I haven’t owned a traditional amp and cabinet, I’m trying to bridge the knowledge gap between real rigs and digital profiling. Any insights into this frequency matter would be greatly appreciated!
Demystifying Guitar Speaker Frequency Response in Profiling
It’s a great question to explore the frequency ranges in guitar amplification, especially when transitioning from traditional amps to digital profilers like the Kemper. You’re right to consider the frequency response of guitar speakers and how they relate to the overall tone, especially when using high-gain profiles.
Guitar speakers are indeed designed to operate within a specific frequency range, typically focused on the midrange frequencies that are crucial for the characteristic sound of an electric guitar. This range is what gives guitars their punch, warmth, and distinct sonic signature. However, the magic of a profiled tone, particularly with Kemper and similar technologies, lies in the entire capture process, which goes beyond just the speaker itself.
The Role of Microphones in Capturing Frequencies
Microphones are the key to understanding the extended frequency range you’re hearing in your Kemper profiles. Unlike guitar speakers, microphones, especially condenser microphones often used in recording guitar cabinets, are designed to capture a much broader frequency spectrum, often extending well beyond 20kHz.
When a cabinet is miked for profiling, the microphone doesn’t just capture the frequencies produced by the speaker cone itself. It also picks up:
- Harmonics and Overtones: Guitar amps, particularly when driven into high gain, produce a complex array of harmonics and overtones that extend into higher frequencies. These are crucial for the richness and complexity of the tone, and microphones capture these nuances.
- Cabinet Resonance and Air Movement: The microphone captures the overall sound of the cabinet, including its resonance, vibrations, and the way air moves around it. These elements contribute to the perceived “air” and “space” in the tone and can contain frequencies beyond the speaker’s direct output range.
- Room Acoustics (to a degree): Depending on the mic placement and the environment, the microphone might also capture some subtle reflections and room acoustics, which can influence the higher frequency content.
Therefore, the profiled tone isn’t solely limited to the frequency response of the guitar speaker. The microphone acts as a broader “ear,” capturing the complete sonic picture of the amp and cabinet, including frequencies that extend beyond what the speaker itself predominantly produces. This is why you hear frequencies in your Kemper profiles that seem to go beyond the typical guitar speaker range.
Fletcher Munson and LPF/HPF in Live and Studio Settings
Your understanding of the Fletcher Munson curve is spot on. At higher volumes (like in live settings), our ears become less sensitive to low and high frequencies relative to the midrange. This is why applying an LPF in live sound is often beneficial – it helps to reduce harshness and potential muddiness in the high end, which can become exaggerated at high volumes due to the Fletcher Munson effect.
For live use, setting your LPF around 6-7kHz is a common practice and helps to create a more focused and less fatiguing guitar tone in the mix. It prevents excessive high-frequency content from clashing with other instruments and becoming overwhelming in the overall sound.
In the studio, where listening volumes are typically lower and the goal is often to capture a wider, more detailed sonic picture, cutting frequencies higher, around 10.5kHz or even more, can be appropriate. This is because:
- Detail and Air: In a studio setting, you might want to retain more of the high-frequency detail and “air” captured by the microphone to create a more nuanced and realistic tone.
- Mixing Context: You have more control in the mixing process to shape the high frequencies and ensure they sit well within the context of the entire mix. You can always further refine the EQ in the mixing stage.
Should You Mimic Guitar Speaker Spectrum for LPF/HPF?
Not necessarily. While understanding the guitar speaker’s frequency range is helpful context, you shouldn’t feel strictly bound by it when setting your LPF/HPF on the Kemper, especially for live use.
Instead, consider these points:
- Listen in Context: The best approach is always to listen to your guitar tone in the context of the full mix, both in live and studio settings. Adjust your LPF/HPF based on what sounds best and sits well with the other instruments.
- PA System Considerations: PA systems are typically full-range and designed to reproduce a much wider frequency spectrum than guitar cabinets. Therefore, you have more flexibility to shape your tone using EQ and filters within the Kemper to suit the PA and the venue.
- Personal Preference: Ultimately, tone is subjective. Experiment with different LPF and HPF settings to find what sounds best to your ears and fits your musical style. There’s no single “correct” setting.
Bridging the Real vs. Digital Understanding
Your journey to understand the nuances of guitar tone, both real and digital, is commendable. Digital profilers like Kemper are incredibly powerful tools that capture the essence of real amps and cabinets, but they also offer flexibility and control that traditional rigs sometimes lack.
By understanding the role of microphones in capturing a broader frequency spectrum and considering the context of live and studio environments, you can confidently shape your Kemper tones to achieve your desired sound, whether you’re aiming for authenticity or exploring new sonic territories. Experimentation and critical listening are your best tools in this process.
