Kavern Plate Reverb / Freeze User Manual
1Welcome
Thank you for choosing the Kavern Plate Reverb / Freeze from Keystone Musical Instruments.
Kavern is built for lush plate reverb, expressive ambience and performance-ready freeze textures, from subtle studio polish to massive sustained atmosphere. Whether you want a classic plate, a wide cinematic wash, momentary infinite hold or layered ambient pads, Kavern gives your signal depth, space and sustain while keeping the controls immediate and musical.
What's new in firmware 1.4 LED brightness adjustments and leveling fixes. There are no changes to controls or functions, so everything in this manual applies to firmware 1.4. Updates are free through Keystone Control Center.
2Product Overview
- Plate reverb voiced for smooth ambience, studio-style depth and performance use
- Freeze for sustaining chords, notes, drones and atmospheric layers
- Dedicated Decay, Pre-Delay, Mix, Damping, Brightness and Depth controls
- Switchable plate Type, room Size and Style voicing
- Momentary and latching freeze for expressive live control
- Stereo output for expansive ambient and studio rigs
- MIDI control and APEX expression
- 128 onboard presets
- For guitar, bass, keyboards, synths and studio use
- Free lifetime firmware updates
3Quick Start
- Connect your instrument or previous pedal to Kavern's input.
- Connect Kavern's output to your amp, pedalboard, mixer, interface or next device.
- Connect a 9V DC center-negative regulated power supply.
- Engage the pedal with FS1, the Bypass footswitch.
- Set Decay for the length of the tail, then Mix for the dry/reverb balance.
- Use Pre-Delay to set the gap before the reverb blooms, then shape the tail with Damping, Brightness and Depth.
- Set Type for bright, warm or dark plate character, Size for small, medium or large, and Style for vintage, classic or modern.
- Press or hold FS2, the Freeze footswitch, to capture and sustain the current reverb.
- Use MIDI, presets or APEX for repeatable settings, external control or hands-free ambience changes.
4Controls
| Control | Range | Function |
|---|---|---|
| DecayPOT 1 | 0.1 s – 20 s | Length of the plate tail, from short, tight ambience to long, spacious reflections and sustained decay. |
| Pre-DelayPOT 2 | 0 – 500 ms | Time before the reverb begins after the dry note. Lower feels immediate and blended; higher adds separation, clarity and rhythmic space before the bloom. |
| MixPOT 3 | 0–100% | Blends dry and reverb. Most live and pedalboard use sits below 50%. At 50% it's an even wet/dry mix, and at 100% (all wet, pure plate) Kavern can serve as outboard gear on a mix bus. |
| DampingPOT 4 | 0–100% | How strongly the tail softens over time. Lower keeps more high-frequency energy; higher gives a smoother, darker, more absorbed decay. |
| BrightnessPOT 5 | −100% to +100% | Tonal focus of the reverb. Negative is darker and warmer; positive adds brightness, presence and definition. |
| DepthPOT 6 · Modulation | 0–100% | Movement in the tail. Lower keeps the plate stable and clean; higher adds animated, evolving motion. |
| FS1Bypass · right | Toggle | Engages or bypasses Kavern. |
| FS2Freeze · left | Press / hold | Captures and sustains the current reverb. Depending on the mode, it works as a momentary freeze or a 360-style control. |
| SWITCH 1Type | Bright · Warm · Dark | The basic plate voice. Bright emphasizes top-end sheen and presence, Warm is a balanced classic plate, and Dark is smoother and more subdued. |
| SWITCH 2Size | Small (50%) · Medium (100%) · Large (200%) | The virtual size of the space. Small is tighter and more focused, Medium is the standard size, and Large is deeper and more spacious. |
| SWITCH 3Style | Vintage · Classic · Modern | The overall EQ contour. Vintage narrows and softens the tone (lo-fi), Classic keeps it balanced (natural), and Modern extends clarity and detail (hi-fi). |
5Footswitches and Performance
- FS1, Bypass: engage or bypass Kavern to add plate ambience for a verse, chorus, solo, transition or ambient passage.
- FS2, Freeze: capture the reverb tail and hold it as a sustained layer. Tap or hold depending on the freeze mode.
- Stereo and width: use stereo for ambient guitar, synth pads, keys and cinematic textures. Use mono for bass and other low-frequency sources, or when the reverb needs to stay focused in a dense mix.
- Stacking: place Kavern after drive, modulation and delay for a traditional ambient chain, or before delay or modulation for experimental sustained textures.
6APEX Expression Control
APEX (Assignable Programmable Expression) is Keystone's expression-control system. On Kavern, expression can sweep Decay, Pre-Delay, Mix, Damping, Brightness and Depth. Use it for hands-free swells, evolving ambient beds, dramatic blooms, tone shifts and smooth moves between subtle ambience and full atmospheric wash.
- Unplug 9V power.
- Hold FS1 (Bypass) while you plug power back in.
- LED 1 (the left LED) blinks rapidly to confirm Kavern is in expression setting mode.
- Move the supported control you want to assign.
- Turn it in the direction you want it mapped: up for up, down for down.
- To set a range instead of the full sweep, hold FS2 while turning the control to set two points, a minimum and a maximum.
- Kavern confirms each point with two blinks. Set the first value, wait for the blinks, then set the second.
- For direct mapping, set the minimum first, then the maximum. For inverse mapping, set the maximum first, then the minimum.
- After both values are confirmed, release FS2.
- To clear all assignments, flip SWITCH 1 (left). To clear only the most recent one, flip SWITCH 2.
- Press FS1 to exit. The LED blinks once for each parameter linked to the expression pedal.
- APEX settings stay on the pedal and can be backed up with Keystone Control Center.
7Keystone Control Center
Keystone Control Center is the free Mac and Windows companion app for Keystone pedals. Connect over USB to configure device settings, manage presets, back up APEX assignments and install free lifetime firmware updates. Download it at keystonemusical.com/pages/keystone-control-center.
8MIDI, Presets and Firmware
Kavern works with pedalboard switchers, MIDI controllers, studio rigs and live performance systems. MIDI handles preset recall, parameter control and performance automation. Kavern stores 128 presets, including effect settings and APEX assignments. Firmware updates are free for life and install over USB with Keystone Control Center.
Kavern uses the MIDI Type-A TRS standard for MIDI In and MIDI Thru. MIDI Thru repeats everything arriving at MIDI In, so one connection on the first pedal can carry tempo, CC and PC messages down the whole board over inexpensive TRS cables instead of bulkier 5-pin MIDI cables.
9MIDI CC Mappings
Continuous parameters
| CC | Parameter | Pot | Range |
|---|---|---|---|
| 23 | Decay Time | POT 1 | 0.1 s – 20 s |
| 24 | Pre-Delay | POT 2 | 0 – 100 ms |
| 25 | Mix | POT 3 | 2–100% |
| 26 | Damping | POT 4 | 0–100% |
| 27 | LFO Rate | POT 5 | 0.05 Hz – 2000 Hz |
| 28 | Modulation Depth | POT 6 | 0–100% |
Three-position switches
| CC | Parameter | Position 1 (0–42) | Position 2 (43–84) | Position 3 (85–127) |
|---|---|---|---|---|
| 29 | Plate TypeSWITCH 1 | Bright | Warm | Dark |
| 30 | Room SizeSWITCH 2 | Small | Medium | Large |
| 31 | StyleSWITCH 3 | Vintage | Classic | Modern |
10Suggested Sounds
| Sound | Starting point |
|---|---|
| Classic plate | Moderate Decay, short Pre-Delay, medium Mix, moderate Damping, neutral Brightness and low Depth for a polished studio plate. |
| Ambient wash | Longer Decay, medium Pre-Delay, higher Mix, Size on Large, slightly positive Brightness and medium Depth for spacious chords and atmosphere. |
| Frozen pad | Capture a chord with FS2, balance the sustained layer with Mix, and shape the tail with Damping, Brightness and Type. |
| Dark cavern | Long Decay, higher Damping, negative Brightness, Type on Dark and Style on Vintage for a warm, deep, subdued space. |
| Solo bloom | Medium Mix, medium-to-long Decay, moderate Pre-Delay and slightly positive Brightness so lead lines stay clear before trailing into plate sustain. |
| Animated plate | Long Decay, medium Mix, neutral-to-positive Brightness and higher Depth for a moving, evolving tail. |
11LED Color Standards
Kavern's signature color is dark blue . Universal colors are the same on every Keystone pedal and mark configuration modes and special states.
| State | Color | When used |
|---|---|---|
| I/O Mode Config | White | Boot mode: selecting audio routing |
| APEX Mode | Magenta | Boot mode: expression pedal assignment |
| MIDI Sync | Bright green-cyan | Synced to MIDI clock |
| Tap Tempo | Cyan | Tap tempo learning mode |
| Save Confirm | Bright green | Settings saved successfully |
| Clear/Delete | Amber | Clearing assignments or settings |
12Troubleshooting
| Problem | Try this |
|---|---|
| No sound | Check the input, output, amp or interface, bypass status, cables and power supply. |
| Reverb is too subtle | Raise Mix or Decay, lower Damping if the tail is too muted, add Brightness for presence, and make sure the pedal is engaged. |
| Reverb overwhelms the dry signal | Lower Mix or Decay, add Damping for a smoother tail, or reduce Brightness if the reverb feels too forward. |
| Freeze doesn't engage | Check the freeze mode, press or hold FS2 as needed, and make sure signal is reaching the reverb. |
| Frozen layer is too loud or quiet | Adjust Mix, Decay, Damping and Brightness until the sustained layer sits right with your dry signal. |
| MIDI control doesn't respond | Check the MIDI channel, cable direction, controller mapping and CC numbers. |
| Expression pedal doesn't respond | Use a compatible expression pedal and cable, reconnect it, then reassign the control in APEX mode. |
| Firmware update fails | Restart the update, try a known-good USB cable, and make sure the updater and firmware files come from Keystone Musical Instruments. |
13Specifications
| Product | Kavern Plate Reverb / Freeze |
| Firmware | 1.4 |
| Effect type | Plate reverb and freeze ambience |
| Primary uses | Classic plate, ambient wash, sustained freeze layers and expressive performance textures |
| Controls | Decay 0.1–20 s; Pre-Delay 0–500 ms; Mix 0–100%; Damping 0–100%; Brightness −100 to +100%; Depth 0–100% |
| Switches | Type Bright, Warm, Dark; Size Small (50%), Medium (100%), Large (200%); Style Vintage, Classic, Modern |
| Freeze | Momentary, latching and fade-style operation depending on configuration |
| Audio | Mono, stereo and wide routing |
| MIDI | Type-A TRS In and Thru; CC control and preset recall |
| Presets | 128 onboard presets, including supported APEX settings |
| Expression | APEX expression control |
| Compatibility | Guitar, bass, keyboards, synths and studio signal chains |
| Power | 9V DC center-negative regulated supply |
| Warranty | One year from the original purchase date |
14Care and Safety
- Use only the recommended power supply.
- Keep the pedal dry and away from extreme heat, cold, dust and moisture.
- Disconnect power and cables before cleaning.
- Clean the enclosure with a dry, soft cloth. Don't use solvents or abrasive cleaners.
- Don't open the enclosure unless instructed by qualified service personnel.
15Warranty and Support
Keystone Musical Instruments warrants the Kavern Plate Reverb / Freeze against defects in materials and workmanship for one year from the original purchase date. The warranty doesn't cover damage from misuse, unauthorized modification, accident, improper power supply, liquid exposure or normal wear. For service, registration, firmware updates and support documents, visit keystonemusical.com.
