How we build our IEMs

by DANIEL WIGGINSMay 05, 2020

We thought it would be instructive to share with you how we assemble our IEMs.  Yes, we do it all in-house, one at a time.  Every step, from setup through testing, is fully recorded and narrated.  In fact, we'll include the narration text below if you'd like to read along!

Anyway, we hope this video shows the attention to detail and the intelligence we put into the design of our IEMs.  Each part is designed to only assemble to the other parts in just one way - you can't put something in backwards, or misalign it.  We use keyways, slots, and tabs to ensure perfect alignment.

We are also quite careful with the glues chosen, using specific polyvinyl acetate and cyanoacrylate glues that were chosen for durability and suitability for the job.  Note that the glues we use reach as high as $500 per gallon!  These aren't cheap glues.

Overall, because of the attention during the design process - designing for manufacturing from step one - we're able to make a set of IEMs in about 6-7 minutes.  Now, it goes slower in this video because we're slowing down to talk you through the process.  But we can build 9 to 10 pairs in a single hour, by a single operator.  With more than 99% pass rates.

Periodic Audio - designed for excellence, in performance AND manufacturing!



Hi, I'm Dan Wiggins, Acoustics geek here at Periodic Audio. In this video we're going to show you how we assemble our IEMs. We'll cover how we put all the parts together to pull off how we make our award-winning products. Now, we're NOT going to cover how we build our transducers - that has several proprietary trade secrets - including the equipment used. But we'll show you everything else, how all the other parts come together. And yes, we do it all right here in Ventura, California. We don't outsource our assembly or testing, we own it all as you'll soon see. So with that, let's get started.

The first step, like any good manufacturing process, is to pull together all the individual parts you'll need. In this case, we use our own custom-designed and 3D printed assembly tray and jig. This jig - in white - holds all the parts needed and provides a few mounted tools to assist in the process of assembly.

Right now, this jig is loaded with the outer bodies - left and right. While we use the same tooling for the left and right sides, we do pre-press different grilles - red or black - to indicate which side is which. We're not showing the press process as it's really not that important to the overall assembly.

This jig also holds the port tubes - yes, we use discrete port tubes to provide the extremely deep, powerful, and exceptionally low distortion bass we're so well known for. The port tube is a small, molded component with a mounting flange and is color-coordinated to match the rear counterbalance.

It also holds what we call the PC core - an inner, non-visible component that seals the acoustic chamber completely. This part ensures we have a perfect acoustical seal, the chamber is of the right volume, and keeps all glue lines completely invisible.

We also have our rear counterbalances, ready for mounting. These are metal injection molded components, made of 304 grade stainless steel. Each part is then polished on the outside surfaces, before being vapor-deposition coated in the desired finish.

And of course, a full line of transducers. These are the heart of the beast. Our own, custom-designed 10mm diameter unit, it's exactly 10mm in diameter, 4.5mm tall, and shares all the same parts for each model save for the material we use for the diaphragm.

This jig holds enough parts to make 10 pairs of IEMs. As you'll see, it's not a complex process, and a trained assembler can build 10 units in about 90 minutes. Part of this speed comes from the ease of assembly we designed in to each part, and the fact that each part has keyed features that force alignment in only one way. It's literally impossible to build one of these wrong; if we do have a failure of assembly, it's typically a polarity issue (where the voice coil was wired upside down) or a scratch on the body from handling.

We start the process by adding a gasket to the front of the transducer. This is a custom die-cut closed cell foam gasket, with PSA on both sides. It lives on its own sheet of backing so it doesn't get stuck in the jig. We take the gasket and add it to the front the of the transducer. Once the seal is completed and inspected, we place the transducer on a weighted magnet stand to hold it for the next steps.

Next, we take one of the leads from the cable assembly and feed it through the neck of a body. The wires are color-coded: red and plain for right, and green and plain for left. Plain indicates a common ground for audio. In this case, we're connecting into the left body, so we're using a green and common lead from the cable assembly. The cable is pushed through the neck, and then brought over to the transducer.

As mentioned earlier, the transducer is held in position on a weighted base with a magnet. This keeps it oriented in the proper position and holds it for the next step, which is to solder the cable assembly leads to the transducer. As we're dealing with very high-strength neo magnets, we use pure copper tips in our Hakko soldering station. Copper is non-magnetic, so the tip isn't pulled around by the magnet. We only use lead-free solder so that we can export our products world-wide.

Once the soldering is completed, we then mount the transducer. First, we peel off the other PSA cover, so that the gasket is now exposed. The gasket ensures an air-tight seal around the front of the transducer to the nozzle, and also provides a compliant mount to dramatically reduce mechanical vibration noise. The transducer is positioned in the body and we use a custom push-rod, with a soft tip, to fully ram the transducer down to the front of the body and create that seal.

The transducer's rear is sealed as well. We draw a thin bead of polyvinyl acetate glue. This is a soft, flexible, water-based glue that flows into the gap around the transducer.

Once the bead is complete, we mount the cable assembly. The excess wire is pulled through, and then the cable lock is seated. The cable lock has small fingers and hooks that grab on to the internal lip in the body and make a secure connection. These fingers also engage with a boss in the body to prevent rotation, thereby immobilizing the cable lock. The lock is secured to the body by using a drop of cyanoacrylate glue.

Lastly, we dress the excess wire. This is the wire slack needed during assembly. We twist the wire into a small spiral, then tuck it in next to the transducer, to ensure it is clear and will not interfere with the next assembly steps.

Now we move on to the port installation. First we add a small drops of glue to the inside of the main body where the port will mount. This is the same CA glue as used in the previous steps. we take a port from the jig, and place it on the port installation tool. This tool is mounted to the jig, and has a small spur that locates the port and holds in perfect alignment. This enables simple positioning of the main body, then pressing down on the port for a few seconds to completely secure the port to the body.

Note that because the port is quite long, given the dimensions inside an IEM, it must be mounted after the transducer as otherwise it would block the transducer from fitting into the body.

Now it's time to seal things up. We use the CA glue again to place a few drops on the side of the port. These drops will be used to secure the PC core to the assembly so that we can apply a complete seal. The PC core is keyed so that it fits around the port tube and the cable lock - you cannot install it upside down or rotated in any way. The PC core snaps into place with an audible click, letting the assembler know it's fully seated.

We then pull back the strain relief to expose the cable lock molded around the cable. We apply a small drop of the same CA glue used in other steps. We bring the strain relief back up over the cable lock and spin the relief to spread the glue all the way around. When it dries, in about 2 minutes, the strain relief will never come off without severe abuse.

Then we seal the PC core. We use the PVA glue to draw a bead around the junction of the PC core and the main body. This creates the internal, airtight seal for the acoustic chamber and that guarantees perfect acoustics. There is a molded groove that provides a place to solidly locate the glue so it does not flow out.

Now it is time to finish the assembly. We use a few drops of the CA glue on the back of the PC core. The PC core has a pair of alignment holes that match with pins on the back of the caps. We cover these holes and the space between with the CA glue. A cap is selected and aligned so that its pins can press through the holes. This glues the pins into the holes and the cap to the PC core. Excess glue does not squeeze out because of the glue groove in the PC core. The unit is visually inspected to be aligned, and the assembly is complete.

Once one side is completed, we place it in the curing holder built into the jig. And then we repeat the process for the other side. The entire process is the same, since we maintain a high degree of symmetry between the two sides. The only difference is which cable assembly lead is used and which color grille for the main body is used. The other side is placed into the jig allowed to sit for 1 minute to finish drying.

Once the drying process is finished, it's time to acoustically test the units. For this step, we use a Crysound 6151B analyzer. The 6151 tests both sides simultaneously. We place one of each side into an IEC711 standard coupler, mounted to its matching 506 preamplifier. This system measures the frequency response, distortion, impedance, polarity and sensitivity of each channel as well as overall channel balance. We run these tests at 566 millivolts, representing a 112 dB SPL average level. And as you can see, it takes about 3 seconds to do all these measurements. The results are shown as green for pass, red for fail.

And there you have it! That's how we build - and test - every single IEM we ship. All done in-house, one unit at a time. Highly repeatable because of the engineering. Designed to be asesmbled just one way, tooled to provide the clearances and tolerances we need, and tested to ensure perfect sound. After this process, it's simply a matter of placing them in their packaging, along with the accessories, and then send out to our growing customer base.

I hope you've enjoyed this little video covering how we do things here. Yes, it's all hand-built right in Ventura, California. We own every step of the process, from engineering, to tooling, to production, to testing. It's this attention to detail, and complete ownership of the process, that enables us to offer our class-leading 5 year warranty. Our products are just better because they're designed - and built - that way.

Thanks for stopping by!