Explaining the Loudspeaker Design Process

Designing a high-quality, long-lasting loudspeaker system that produces application-specific sound performance, possibly in a harsh or noisy environment, is not a job for amateurs. Engineering experience and extensive knowledge of the complicated physics of sound and acoustics are prerequisites to creating the perfect system for your application.

A dose of educated wizardry and imagination, along with careful modeling and testing, are also critical components of any successful speaker design.

Establishing Requirements for an OEM Audio Solution

When the engineers at an original equipment manufacturer (OEM), like MISCO, receive an order for a new custom-designed loudspeaker driver or loudspeaker system, they begin to define target statistical parameters to meet the expectations in three categories:

The “building block” design parameters are:

• Performance: Frequency response, sensitivity, power handling, and impedance are the primary specifications.
• Mechanical: Mounting requirements based on the space available, including speaker diameter, depth, and weight.
• Environmental: Indoor or outdoor exposure, power source, temperature variances, chemical resistance, flame resistance, and other potentially compromising factors.

These parameters are often reviewed by the OEM’s sales engineer to determine if a product exists that already meets them. If not, the engineer looks at existing products that could be customized slightly. If that’s not an option, a design engineer gets involved and begins the process of designing a loudspeaker that will do exactly what a customer needs.

Establishing How Many, When, and the Cost-per-Unit

As with any manufactured product, defining factors like economies of scale, component sourcing decisions, and production times are critical in determining the target cost. Without careful planning, the production of custom loudspeakers can easily exceed the target cost.

Detailed production cost analysis is an integral part of the initial design process. Sharing cost targets, budgets, or not to exceed targets enable designers, procurement specialists, and production managers to determine the best cost scenario that satisfies all the quality design parameters.

The analysis begins with reviewing the performance, mechanical, and environmental parameters, projected volume production, and a target cost based upon a projected selling price. Essential costing elements are:

• Size of the speaker
• Power handling expectation
• Magnet types
• Cone body and edge materials
• Unique treatments to withstand extreme conditions

There are several supply chain questions that need to be answered around component sourcing as well.

• Where will the speakers be delivered - in the US or somewhere else in the world?
• Will you want the OEM to carry finished stock, safety stock, or just stock to order?
• Do you want a vendor-managed inventory system (VMI) for just-in-time inventory?
• Can there be a benefit in asking the OEM to look at next steps of assembly to reduce handling costs?

Another consideration is where you want your speakers manufactured and assembled. While most OEM speaker manufacturers offer only manufacturing in Asia, there are a few, like MISCO can that can produce products in both the US and Asia. This provides many advantages for your own supply chain management. Asia assembly can be cheaper on larger scale orders or for international delivery. However, if your delivery location is in North America, near-sourcing your speakers can shorten lead times, reduce freight, and inventory costs. US production helps avoid shipping delays and makes communications throughout the process easier.

Once these decisions are made, a final agreement detailing specifications and acceptance criteria is formalized with the customer. Development costs, where necessary, are determined and charged appropriately.

Creating Loudspeaker Prototypes

Once the specifications and commercial requirements are agreed upon, designers render engineering drawings and create a Bill of Materials to solicit cost proposals from prospective suppliers. Functional samples and prototypes are then assembled for customer review and testing. Advances in acoustical design software and 3D printing technology has sped up the process for creating prototypes.

Stringent Speaker Performance Testing

At this point, rigorous performance testing protocols should be used to measure each parameter to ensure all specifications of the samples meet or exceed agreed-upon performance levels. Acoustical testing, using advanced analysis such as Klippel small signal (LPM) and large signal (LSI) analysis, and measuring the speaker’s total harmonic distortion (THD), intermodulation distortion (IMD), power handling, maximum output, power threshold, sound pressure level, are requisite.

A revolutionary new Klippel Near Field Scanner (NFS) technology relies on robotics to measure a speaker’s performance in 3D and provides even more insight into the speaker's performance. Testing in a Klippel vacuum chamber can remove the impact of air on how a speaker performs. This is especially useful when testing micro speakers. Laser scanning can be used to detect exactly how a transducer cone is vibrating and help diagnose audio problems as well.

Long-term power or environmental testing can determine the durability and useful life of the equipment, often a requirement for military, FAA, and other clients who need exceptional reliability in their speakers. After the OEM is satisfied it has met the agreed-upon specifications, prototypes should be sent to you, the customer, or for QC analysis and evaluation in the anticipated application and environment where the speakers will be used. If the OEM has done their job properly, your evaluation should go smoothly and quickly.

Gearing Up Speaker Production

Once the prototypes and samples have proven to perform as planned, you place the Purchase Order with the OEM and activate their supply chain to procure all necessary materials. Once materials are received, the production team builds and tests initial loudspeaker units to streamline larger-scale production. An end-of-line testing routine is created. A robust quality control process ensures the finished products meet expected quality standards unit to unit, batch to batch, year to year. Each speaker produced should undergo thorough performance testing, frequency response tests, impedance measurements, distortion evaluations, before being shipped to you.

Ordering a custom speaker for your exact application doesn’t have to be daunting or expensive if you have chosen an experienced and trustworthy loudspeaker manufacturing partner to help you through the process.