TPCD
Technology
 
 
 
 

The Problem with Traditional Diaphragms

Traditional diaphragms are unable to control resonances resulting in areas of the diaphragm not accurately following the motion of the voice coil. This means that soundwaves created by the diaphragm is different from the ingoing audio signal and the sound is distorted.

 

 

 

 

      

 

Traditional soft diaphragm

Traditional stiff diaphragm

The Composite Sound TPCD® Solution

Instead of treating a diaphragm as something static being defined and limited by its geometry and material properties, Composite Sound’s philosophy is to treat the TPCD® diaphragm as something that can be engineered, configured and optimized to meet your requirements and realize your visions.

Composite Sound’s engineering approach is to make the entire diaphragm surface follow the movement of the voice coil to accurately reproduce the audio signal. To do so we engineer the diaphragm for pistonic motion over the entire frequency range, while controlling resonances and bending modes as they finally occur.

To achieve this, Composite Sound uses a two-step process: first, optimizing the thin-ply carbon material properties for the specific diaphragm, typically with high stiffness and low mass; second, tailoring the thickness and stiffness in every point of the diaphragm. That enables us to achieve solutions and performance levels far beyond what is possible with conventional diaphragm materials.

TPCD® thin-ply carbon diaphragm

Diaphragm Engineering

The performance and behavior of a speaker or headphone diaphragm, measurable through frequency response and distortion measurements, is dictated by its modal behavior, or in other words how resonances and bending modes occur at different frequencies.

Besides geometrical and material properties, the modal behavior is the result of the stiffness, density and mass of the diaphragm. Every change in stiffness, density or mass in any point of the diaphragm will influence the modal behavior.

By optimizing stiffness, density and mass in every point of the diaphragm it is therefore possible to control the modal behavior and thereby how resonances occur and how the diaphragm behaves at different frequencies.

Simulation Driven Engineering

The possibilities of engineering a TPCD® diaphragm are endless since thickness and stiffness can be tailored, not only axisymmetrically, but in 3D. To make the development efficient, simulations are an integral part of our engineering process.

Unlike isotropic materials such as metals or plastic that have the same material properties in all directions, Thin-ply Carbon is orthotropic, meaning we can tailor the properties in X, Y and Z directions. That means that we also simulate in 3D to optimize the modal behavior, maximize stiffness and minimize mass.

Composite Sound’s simulation engineers can simulate for you, but you may also want to simulate the potential performance of TPCD® in your transducer, loudspeaker or headphone. We are therefore happy to share all required material properties so that you can perform simulations on your own terms.

Click "Simulate TPCD" below to get started!

Simulate TPCD

Thin-Ply Carbon Material Technology

Thin-Ply Carbon is created by spreading carbon fiber yarns into ultra-thin layers, each layer being one fifth the thickness of human hair. 

The Thin-Ply Carbon material possesses multiple characteristics that make it ideal for loudspeaker and headphone diaphragms.

 

    -High stiffness

    -Low mass

    -Freedom of engineering 
TPC spreading (1)

 

 

Thin-Ply Carbon Diaphragms (TPCD®)

 

Thin-ply carbon layers are combined with epoxy resin to create a Thin-Ply Carbon Diaphragm (TPCD®). Through optimization of the number of layers and the orientation of each fiber layer in every point in the diaphragm, the stiffness and thickness can be tailored in every point. This enables effective control of resonances while simultaneously reducing mass and enhancing stiffness.

Composite Sound TPCD® applications include speaker cones, speaker domes, tweeter domes, fullrange cones, fullrange domes, headphone diaphragms and compression driver diaphragms. 
Composite tweeter domes
Compression driver
Textreme cone
ScanSpeak tweeter

Examples
TPCD® vs metal in a mid-woofer

Frequency response curves showing the same 6.5 inch woofer with three different cones but of the same geometry: magnesium, a non-engineered TPCD® by Composite Sound and an engineered TPCD® by Composite Sound.

In the engineered TPCD® thickness and stiffness is optimized in all points of the diaphragm enabling controlled resonances.

Frequency response 6_5 inch (1)
TPCD vs beryllium tweeter dome crop (1)
TPCD® vs. beryllium in a one inch tweeter

The same one-inch tweeter with a TPCD® by Composite Sound vs beryllium.

Test for yourself

Fill in the form to receive more information or explore the potential of TPCD® in your product.