FAQs 06.000

How do I replace my earbuds? Remove the earbuds. This is accomplished by holding the body of the IEM firmly with one hand, and gently twisting and pulling on the earbud with the other hand. It should pop off the end of the IEM. Install a new pair by holding the IEM firmly in one hand, and gently pressing and twisting the earbud back on to the IEM sound tube.

How do I clean my IEMs? Remove the earbuds. This is accomplished by holding the body of the IEM firmly with one hand, and gently twisting and pulling on the earbud with the other hand. It should pop off the end of the IEM. Then the earbud can be washed in hot water, with a little soap (we suggest shampoo - it’s great at getting earwax off the bud).

Completely rinse and dry the earbud. And while the earbud is drying, use a cotton swab to gently brush across the ear canal opening. This will remove any accumulated earwax from the metal grille at the entrance to the ear canal opening.

Why dynamic transducers and not balanced armatures? Dynamic transducers are among the oldest style of audio transducers invented. A small coil of wire (voice coil) moves in a magnetic gap. The force of the motion is dependent upon the current in the voice coil. The current is a function of the impedance (resistance to current) of the transducer and the voltage from your signal source (phone, amplifier, laptop, etc.).

A balanced armature (BA) operates in much the same way, but uses a lever-type construction to create a smaller package with higher efficiency. But that efficiency comes with a cost - it typically has a very peaky, narrow-band response. In fact, BAs were first created - and still dominate - the hearing aid industry where fidelity of sound is secondary to high output and intelligibility. The sound quality is compromised in an effort to get intelligible (not necessarily good) speech quality at high efficiency.

As a result, often multiple BAs are used inside an in-ear monitor, each tuned to a specific frequency range. But this requires the use of a crossover network - a network of small components designed to divide up the audio spectrum to feed parts to each individual BA. The result is often a sonic mishmash - lots of components with little chance of a cohesive result. A look at the spectral decay plot will show the competing resonances and hash in the time domain, a visible confirmation of the problems inherent in a BA-based design.

A wideband dynamic transducer, like the ones used in Periodic Audio products, do not have a crossover network. There are no electrical components between the amplifier and the transducer - just wire. The transducer is responsible for smooth, clean sound from the deepest bass to the highest highs. Proper design of the transducer is essential, but when it is realized - the sonic results in terms of clarity, coherence, and uniform sound over the full frequency range is stunning. And the spectral decay plot is clean and clear - you can see the fidelity you hear.

Rather than chase high efficiency at the cost of complexity of system design and compromised clarity, Periodic Audio chose to go with a quality platform. We adjust the sonic signatures not with multiple electrical components, but with deliberate design changes to the diaphragm, realized with shape and material. We stick to the pure approach: one song, one amp, one driver, one happy ear.

Why a 10mm dynamic transducer? Choosing the right size of a transducer is more art than science. In general, a larger size diaphragm provides more potential output and lower distortion. However, large diaphragms often suffer from reduced high frequency output and diaphragm resonance/breakup - leading to poor spectral decay performance.

An in-ear product also provides it's own limits on what would be a reasonably sized diaphragm. Units bigger than about 13mm are too large to fit in most ears, unless the transducer is completely outside the ear, like on-ear/over-ear (supra or circum aural) headphones.

Many IEMs are made with small diaphragms, in an attempt to get the transducer as close as possible to the eardrum. It is believed that being closer to the eardrum will result in a more pure sound. However that often means using a diaphragm less than 7mm in diameter. Since the area of a circle is proportional to its radius (and thus its diameter), a 7mm transducer will have half the area of a 10mm transducer. And that means, all else being equal, double the distortion and 3 dB less peak SPL.

We settled on 10mm as the best tradeoff between distortion, SPL, extension and resonance/breakup resistance. Using literally decades of experience in the design and production of small transducers, we evaluated fully-refined designs at a multiple of sizes, but in the end our measurements and listening panel tests told us the best overall performance was reached with 10mm. And so - the art led (subjective performance), science confirmed (measurements), and we decided.

Why metal diaphragms? A transducer diaphragm is responsible for converting the mechanical motion generated by the voice coil/motor system into significant air displacement to create the sound experienced by the listener's ear.

The diaphragm couples an edge-force (the edge of the voice coil former) into a planar force that you hear. A diaphragm that is not stiff will not accurately couple these forces together, and the result is typically distortion and a smearing of the sound. Small/fine motions are poorly reproduced so that they are lost, resulting in an audible lack of inner detail of the music. The diaphragm does not operate as a totally unified surface, smearing what you hear.

However, one must be careful about mass as well. Too much mass, and the sensitivity of the transducer is compromised, and typical sources cannot reach satisfactory volume levels. Additionally, too much mass will result in a decrease of high frequency output, leading to a dull sound.

Metals (and certain selected elements) tend to be ideal materials for small transducer diaphragms. They can be drawn to very thin dimensions, to keep the mass down. And the stiffness to weight ratio is exceptionally high, so that - when combined with a high speed-of-sound - breakups are minimized and the diaphragm moves as a whole.

Polycarbonates, mylars, polyurethanes, papers, and other plastic materials are often used, but simply cannot match the stiffness-to-density ratio, the speed-of-sound, nor the high Young's modulus (a measure of stress to strain capability of the material) that you find in metal. We wanted no-compromise in our transducers, as they are the heart of what you hear. So we chose superior metals for our units: pure beryllium, pure titanium, and a very-high-magnesium content magnesium/aluminum alloy (magnesium is an excellent material but is not safe in pure form; alloying with a small amount of aluminum chemically stabilizes the magnesium).

Why polycarbonate bodies? The job of the body of the IEM is three-fold:

1. Hold all components firmly in place relative to each other 2. Provide physical isolation of outside sounds 3. Do not resonate and add extraneous sound to what the user hears

Many companies choose to use metal. Indeed, metal body IEMs are quite ubiquitous as metal is easy to work (it can be machined, no expensive and complex tooling required), takes a wide variety of finishes, and quite easily meets jobs 1 and 2. However, due to the large size of IEM bodies (relative to the transducer sizes), they often fall short in job 3. They will vibrate and resonate (like striking a bell) when used. This means additional complexity to add damping materials to the body to counter the resonances inside the metal.

Rather than using a metal body, most companies choose to use a man-made polymer. Properly designed, a polymer body will do all 3 jobs: components will be properly located and securely held, isolation will be effective as there is enough structure and mass to counter any outside noise, and most plastics are well damped and tend not to support sustained resonances.

However, polymers are more expensive to initially build. Expensive toolings must be made to allow injection molding of components. And usually these toolings contain multiple sliding parts to support a wide variety of holes and protuberances from the main body. Sliding parts in tooling are expensive - and small, precision sliding parts are very expensive.

We chose to use a polymer for our body, specifically polycarbonate. Polycarbonate is a very resilient polymer; in fact, most people know it as "bullet proof glass", or Lexan® (a trademarked version of polycarbonate). Polycarbonate is also used for fighter jet canopies.

The reason polycarbonate is used in all these applications is its ability to bend and snap back. Polycarbonate is a very forgiving material. A sheet of polycarbonate can be bent over 90 degrees before it will crack or break, way beyond other common polymers such as ABS or Acrylic. This resilience to cracking when bending is why it's used to for bullet resistance.

And it also is the acoustical secret it contains: internal dissipation of energy. All polymers do a very good job of damping internal resonances, but polycarbonate just does it a little better.

How are your parts bonded together? There are many ways to bond the components of an IEM together. You can use mechanical fasteners (screws, rivets), designed-in features (snap-locks and threaded features), welding (ultrasonic for plastics, brazing/soldering/welding for metals), overmolding (molded materials), and adhesives (glues).

We use a variety of methods in our designs. We use different adhesives in the assembly of the transducer (three different cyanoacrylates), as well as bonding the transducer to the housing (a thick, compliant and sealing silicone adhesive is used for this critical junction). To secure the grilles to the body, we use an acrylic glue, and to secure the end cap to the main body we use a room-temperature, vulcanized silicone.

The cables are bonded assemblies - we mold the strain reliefs directly to the cable and other components to create a single, permanent assembly. Lead-free, silver-bearing solder is used for all electrical terminations.

All counted, there are a total of 32 discrete bonding processes used in construction of our IEMs. We bond each and every joint, not relying upon friction or simple pressure. Each bond is either an adhesive, overmolding, or welding bond. This provides the highest level of security of each joint and the most consistent results we can guarantee.

What is the best sound? The best sound is what you most enjoy listening to! It is highly individual, as it's based on preference. It is more than just a set of measurements, it's what you experience. You can objectively quantify anything, and from that maybe draw conclusions about what measures the best - but perception goes beyond.

You may hear frequency response, distortion, decay, and other effects - but what you perceive is the combination of all that, what you're feeling like, the temperature in the room, odors, visual cues, etc. That's why what measures best doesn't always correspond with what sounds best.

Perception is much more than one dimension. It's why we also worry about the look and feel of our products. How they feel in your hands and your ears. That has an impact on what you perceive. So with everything wrapped up together, objective data may give you an idea about general trends, but at the end of the day it comes down to experience. The experience of the team that created the product, and the experience you have enjoying the product.

But, if you really want to nail us down about what in-ear monitor has the best sound, we'll tell you - as soon as you tell us the right amount of salt and pepper to put on a steak!

Why is your packaging so "basic"? Simply put: YOU DON'T LISTEN TO THE BOX. As long as your product reaches you without damage, then the packaging did its job. Packaging shouldn't sell you on the product. It should not be one of the "brand promises" to you. It's the product inside that matters.

Compliance and CA Prop 65 Warning Our products are: RoHS, 94V0, EN50332, IEC 61000-4-2 level 4, WEEE, and CE compliant. They are not food-safe, nor are they mission or life critical. They are not microwave or dishwasher safe.

And per California Proposition 65, our products contain substances (including but not limited to: beryllium, nickel, acrylamide, and urethane) which are known to the State of California to cause cancer and birth defects or other reproductive harm. Note that according to the State of California, toast, beer, and prune juice are also known to cause cancer. Seriously. We're not making that part up. For more information go to www.P65Warnings.ca.gov