Headphones and earphones
Head- and earphone design from the ground – based on years of experience
Design Target
Getting the sound you want.
We see a lot of variations between our customers preferred target response.
Some of this can be explained by physiological differences in the ear canal size/dimension and others are probably caused by differences in the music style and music traditions in between the various regions in the world.
Some customers prefer the target response based on the research by Harman (often referred to as “the Harman curve”) and others prefer a lot of sub bass or extreme bandwidth. In either case Ole Wolff will adapt to these different customer requirements and tune the headphone / earphone accordingly.
A measured headphone response (magenta curve) compared to the target response (blue curve).
Simulations
Analyzing and understanding the acoustics is key.
At Ole Wolff we offer to set up acoustic simulations containing all the elements in the transducer as well as in the air surrounding the driver inside the headphone/earphone. Depending on the application and complexity of the headphone design, either a 2D spice model or a full Comsol™ model is built. Using this setup we can quite accurately predict the sound performance and adjust parameters according to the customer’s wishes.
At Ole Wolff we offer to set up acoustic simulations containing all the elements in the transducer as well as in the air surrounding the driver inside the headphone/earphone. Depending on the application and complexity of the headphone design, either a 2D spice model or a full Comsol™ model is built. Using this setup we can quite accurately predict the sound performance and adjust parameters according to the customer’s wishes.
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Coupler impedance
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IEC 711 coupler
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Front leakage with optional acoustic mesh
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Driver modelled using TS parameters
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Rear leakage with optional acoustic mesh
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Air volume behind driver
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Internal air volume inside driver
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Air volume in front of driver
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Optional acoustic mesh on outlet
Earphone modelled in Comsol™ using pressure acoustics and lumped electrical+mechanical parameters of the driver. Symmetry used in order to reduce calculation time.
Very often both 2D and 3D simulations are used to simulate the influence of leakage holes, front- and rear cavities etc.
COMSOL Multiphysics® is used to optimize linearity of the compliance and break-up modes. Image shows motion analysis performed on a diaphragm for a 50mm receiver.
Prototyping
Drilling holes, modifying front-to-back leakage, changing mesh densities…
The above mentioned simulation tools helps us in giving the customer a very short delivery time for actual having the prototypes in hand for initial listening tests and also laboratory tests for documentation.
Normally “soft Tooling” parts will be made based on these simulation results using 3D printing. Laser Cutting, CNC processing, etc. leading to hand assembled prototypes ready for sharing with our customers for their evaluation.
The Ole Wolff head and torso simulator measuring a pair of noise cancelling headphones.
Verifying the performance
Using standardized test methods
The Laboratories at the Development sites of Ole Wolff in Denmark and China are fitted with the most advanced standardized measurement equipment especially developed for the verification of performance of professional audio consumer products.
This includes Artificial ears, Head & Torso simulators, Anechoic Chambers etc. and are all parts of standardized test methods used and acknowledged all over the World.
This makes it possible for us to communicate test results in the same technical “language” as our customers, as well as other independent laboratories, are using.
Do you want to know more about head- and earphone design
Send an e-mail or contact your local sales contact to learn what Ole Wolff can do to help developing your products.