This Device is Not a High-Fidelity Wonder

…but rather an experimental sound station. It delivers metallic, dense textures that are perfectly suited for industrial, ambient, or percussive experiments (like our condom samples).

Materials (Shopping List) for the €50 Plate Reverb

Wood & Metal:

• Wooden slats: approx. 3–4 pieces (Dimensions: 2 x 50 x 200 cm)
• Trapezoidal metal roofing sheet: 100 x 100 cm (aluminum or galvanized steel)
• Accessories: Wood screws, metal brackets, 4 tension springs with eyelets, 4 screw hooks (with wood thread), metal screws, and nuts.

Electronics & Audio:

• 1 surface transducer (Exciter): 20 to 30 watts (acting as the “transmitter”)
• 2 to 6 piezo pickups: (acting as the “receivers”)
• Connectors: Several jack sockets (mono), some wire/stranded wire, adhesive tape.

Tools:

• Cordless screwdriver, drill, soldering iron, pliers.

DIY Guide for the €50 Plate Reverb

Step 1: The Frame (The Skeleton)

First, build a sturdy frame from the wooden slats with an inner dimension of 110 x 110 cm.

Screw the slats together using metal brackets.

Stability Trick: Screw short cross-pieces (feet) onto the underside of the frame. This keeps the frame stable and prevents the wood from warping easily.

Step 2: The Suspension (The Decoupling)

Screw the 4 screw eyes (hooks with wood thread) into the inside corners of the frame.

Drill a hole into each of the four corners of the corrugated/trapezoidal sheet metal.

Hang the sheet metal inside the frame using the tension springs.

Important: The metal sheet must swing freely and must not touch the wood anywhere. The springs ensure that impact noise from the floor is minimized and allow the metal sheet to develop its own resonance.

Step 3: The Driver (Input)

Drill a hole into the metal sheet (in the center, or slightly offset for different resonance modes).

Screw the surface transducer (tactile transducer) firmly onto the metal sheet.

This is your “Input.” The signal from the mixing console (Aux Send) is fed in here. Since the transducer requires power, it is recommended to place a small, inexpensive Class-D amplifier in between.

Step 4: The Pickups (Output)

Now the piezos come into play.

Attach the piezo elements to various spots on the metal sheet using tape.

Experiment here: It will sound different in the troughs of the corrugated sheet compared to the ridges.

Solder the piezos to the jack sockets, which you can mount on a small wooden board attached to the frame.

The Concept: Shaping Sound Through Density

The unique aspect of this setup is the use of multiple piezos. Because the corrugated sheet metal generates complex reflection patterns due to its shape, each piezo captures the reverb with a time delay and a distinct tonal character.

Pro Mixing Tricks:

Route the individual piezo signals back into your mixing console separately.

• Panning: Pan two piezos hard left/right to create a wide stereo image.
• Summing: Blend multiple piezos together to “thicken” the density of the reverb.
• EQ Ducking: Since corrugated metal is prone to metallic “clattering,” slightly cut the midrange frequencies on your EQ to simulate a deeper, darker space.

Don’t expect a Lexicon-style reverb. What you get instead is a unique, mechanical effect that is alive. It reacts to the dynamics of your music, physically vibrates in the room, and gives your productions an organic texture that no plugin can “easily” replicate. It is ideal for anyone looking for the beauty in imperfection.

If you are tired of sterile VST reverbs and looking for a shimmer that sounds like a haunted industrial hall, this project is for you. We are building a “Plate” Reverb using affordable materials from the hardware store. It’s not a Lexicon, and it’s not meant to be—it’s an electromechanical instrument designed for experimental textures and metallic grit.

The Concept

Most professional plate reverbs use a massive, flat steel sheet. We are breaking the rules by using a Trapezoidal Roofing Sheet. The ridges change the way sound waves propagate through the metal, resulting in a complex, dense, and slightly “trashy” reverb tail that is perfect for industrial, ambient, or lo-fi productions.

Shopping List & Tools

Hardware Store Materials:

• Wooden Slats: (e.g., 2x50x200 cm) for the frame.
• Corrugated Trapezoidal Sheet: (100×100 cm, galvanized steel or aluminum).
• 4 Tension Springs: With loops/eyes.
• 4 Eye-Bolts/Hooks: With wood thread.
• Metal Brackets & Wood Screws: For frame stability.
• Machine Screws & Nuts: To mount the transducer.

Electronics:

• 1 Surface Transducer (Exciter): 20W to 30W (This “plays” the audio into the metal).
• 2 to 6 Piezo Pickups: (These “capture” the vibrations).
• Mono Jack Sockets: (6.35mm / 1/4 inch).
• Hook-up Wire & Electrical Tape.

Tools:

• Cordless Drill & Metal Drill Bits.
• Soldering Iron.
• Screwdriver.

Step-by-Step Construction

1. The Heavy-Duty Frame

Build a square wooden frame with an inner dimension of 110 x 110 cm. This ensures a 5cm gap on all sides for the 100×100 cm plate.

• Stability: Screw short pieces of the slats to the bottom corners as “feet” so the frame stands vertically.
• Bracing: Use metal brackets to ensure the frame doesn’t warp under the tension of the springs.

2. Suspending the Plate

The goal is to let the plate float so that vibrations don’t escape into the floor.

• Drilling: Drill one hole in each of the four corners of your trapezoidal sheet.
• Hooks: Screw the 4 eye-bolts into the inner corners of the wooden frame.
• Tension: Attach the springs between the frame hooks and the holes in the plate. The plate should now hang freely in the center of the frame. It should “ring” when you tap it.

3. The “Voice” (Input)

We use a surface transducer (exciter) to turn the plate into a speaker.

• Drill a hole in the middle (or an off-center position for a different character) of the plate.
• Bolt the Transducer firmly to the metal.
• Note: You will need to send your “Reverb Send” signal from your mixer into a small power amplifier (like a cheap Class-D amp) to drive this transducer.

4. The “Ears” (Output)

Instead of one microphone, we use multiple Piezo Pickups.

• Tape the Piezos to different spots on the plate using strong adhesive tape.
• Because the trapezoidal sheet has ridges and valleys, every position sounds different.
• Pro Tip: Place two Piezos on opposite sides for a wide (though phase-coherent) stereo-ish effect.

5. Wiring & Final Touches

• Mount a small wooden board to the side of the frame to hold your jack sockets.
• Solder the wires from the transducer and the piezos to these jacks.
• Keep your wiring neat with tape to avoid “rattling” against the frame.

How to use it in your Mix

1. Send: Auxiliary Send -> Small Amp -> Transducer.
2. Return: Piezos -> Mixer Inputs (Use high-gain/Hi-Z inputs if possible).

The Magic of Multi-Tracking: Since you have up to 6 Piezos, don’t just use one. Bring them all into your mixer on separate channels. Each Piezo captures a different frequency resonance of the trapezoidal sheet. By mixing these signals, you can “thicken” the reverb tail or EQ the “metal” out of specific channels to create a dense, shimmering atmosphere.

Don’t expect a pristine hall. This device is alive. It hums, it rings, and it has a soul. It is a physical object that reacts to your music. For experimental sound design, it’s an absolute goldmine.

Happy Building! Let us know how your “Trapezoidal Reverb” sounds!

Building on your DIY Plate Reverb, the leap from a “science project” to a studio-ready tool often lies in the impedance matching and shielding. Piezos are high-impedance devices; if you plug them directly into a line input, they will sound thin (no bass) and act like giant antennas for hum.

Here is the technical follow-up in English, designed for a blog or forum.

Part 2: Taming the Noise – Pre-Amps & Hum Reduction

If you’ve connected your Trapezoidal Plate Reverb and noticed it sounds “tinny” or suffers from a constant 50/60Hz hum, don’t worry—that’s normal for high-impedance (Hi-Z) DIY builds. Here is how to fix it with a simple Pre-Amp circuit and a grounding strategy.

1. The Simple “Buffer” Circuit

Piezos need a high input impedance (at least 1–10 $M\Omega$) to capture the full frequency range of the plate. Without a buffer, you lose all the beautiful low-end resonance.

The Schematic Concept (JFET Buffer):

You can build a simple “JFET Buffer” using a single transistor (e.g., J201 or 2N5457).

• Components: 1x JFET Transistor, 1x 10 $M\Omega$ Resistor (Input), 1x 10 $k\Omega$ Resistor (Source), 1x 10 $\mu F$ Capacitor (Output).
• Power: 9V Battery (cleaner than a cheap power supply).
• Result: This converts the weak, high-impedance Piezo signal into a strong, low-impedance signal that your mixer loves.

Pro Tip: If you don’t want to solder a circuit, use a DI Box with a high-impedance input or a cheap Acoustic Guitar Pre-amp pedal for each Piezo.

2. Reducing Hum and Interference

Since your metal plate is basically a massive antenna, it will pick up electromagnetic interference (EMI) from your lights, computer, and monitors.

A. The “Grounding the Shield” Method

The most important step is to turn the plate itself into a shield.

1. Ground the Metal Plate: Take a wire and connect it from the metal plate (use a screw/washer) directly to the ground/sleeve of your output jacks.
2. Shielded Wiring: Use “shielded” audio cable (coaxial) for the run between the Piezos and the jacks. Do not use simple copper wire for long distances.

B. The “Hum Destroyer” Circuit (Differential Pair)

If you are using two Piezos, you can wire them in a Pseudo-Balanced configuration to cancel out hum:

• Wire Piezo A to the “Hot” (+) of your XLR or TRS jack.
• Wire Piezo B (flipped upside down) to the “Cold” (-) of the jack.
• Interference that hits both Piezos simultaneously will be cancelled out by the phase inversion, while the mechanical vibration (which hits them slightly differently) remains.

3. Mechanical Hum (Isolation)

Sometimes “hum” isn’t electrical—it’s the sound of your building!

• Soft Mounting: Ensure your wooden frame sits on rubber pucks or old carpet.
• Tension Check: If the springs are too tight, they can transmit vibrations from the frame to the plate. They should be just tight enough to keep the plate from sagging.

Summary of the “Silent” Build:

1. Piezo -> Shielded Cable -> JFET Buffer -> Mixer.
2. Plate -> Earth/Ground.
3. Exciter -> Separate Power Supply (keep the amp power away from the Piezo lines).

With these steps, your experimental reverb will move from “noisy junk” to a “boutique lo-fi processor.” It will still have its unique, dark character, but without the annoying buzz of the modern world.

A microphone shield is a great way to reduce unwanted noise in your recordings. It can help to block out background noise from your environment, such as traffic, people talking, or air conditioning. This can lead to cleaner, more professional-sounding recordings.

There are many different ways to make a microphone shield. One simple and affordable option is to use egg cartons and furniture foam. Egg cartons are a good choice because they are lightweight and easy to cut. Furniture foam is a good choice because it is soft and absorbent.

Materials

• Egg cartons
• Furniture foam
• Tape
• Scissors
• Ruler
• sturdy wire
• old broomstick
• Christmas tree stand

Instructions

Cut the egg cartons into pieces that are the same size as the microphone you will be using.

Egg cartons for microphone shield

Cut the furniture foam to fit the inside of the egg carton pieces.

Furniture foam for microphone shield

Glue or tape the egg carton pieces together to form a cube or other shape.

Egg carton and furniture foam shield

Cut a hole in the front of the shield for the microphone. The hole should be large enough for the microphone to fit through comfortably.

Attach the shield to your microphone stand.

Tips

To make the shield more effective, you can use multiple layers of egg cartons and furniture foam.

You can also add a layer of acoustic foam to the inside of the shield. Acoustic foam is designed to absorb sound waves, which can help to further reduce unwanted noise.

If you are using a large microphone, you may need to use a larger shield.

Testing

Once you have made your microphone shield, it is important to test it to make sure it is effective. Record some audio with the shield in place and then record some audio without the shield. Listen to the recordings and compare the sound quality. You should notice a significant difference in the amount of unwanted noise in the recordings with the shield.

With a little bit of time and effort, you can make a simple and affordable microphone shield that will help to improve the sound quality of your recordings.