Sebastian, the medical technology sector has always been in great demand and particularly so during the current pandemic. Has this had an effect on your sector?

Yes, indeed. We produce a lot of loudspeaker models for ventilators, for customers in Sweden, among other locations. We received a letter from the Swedish embassy during the pandemic, stressing how important our loudspeakers were for the production of ventilators there. And, as we know, Sweden is not alone in this situation. Demand is sure to continue in the near future.

Besides ventilators, there are hundreds of medical devices. Where exactly in this field are loudspeakers from VISATON in demand?

We work with manufacturers from the medical technology sector, which produces measuring equipment, but also with suppliers of magnetic resonance scanners. One area in which we support a lot of customers is in patient monitoring, which includes all the devices that are used for monitoring a patient's health using screens. Many people are familiar with the typical beeping of a heart monitor that emits warning signals. Another positive example is the moment when expectant parents see their child on the ultrasound monitor for the first time and hear its vital signs.

These are very sensitive areas.

They are indeed. Monitoring is about error-free recognition – very often detecting vital signs within seconds. By combining graphics and sound, specialist staff quickly know what needs to be done to help the patient. The equipment must work in all circumstances. Take defibrillators for example: the latest models have loudspeakers built into them that give precise instructions on what to do to resuscitate a person. The chances of survival in extreme situations are likely to increase if the speakers deliver clearly intelligible sound.

And how about in the operating theatres?

There are many loudspeakers hidden around operating theatres, which is why this is an important area for us with fairly extreme requirements. The activities during emergency operations are very hectic. Equipment is pushed around, knocks against other equipment, gets splashed with fluids and more. The space inside an ambulance is even more restricted. In addition to the communication between the driver's cab and the patient area, all speakers are installed in such a way that, after a patient has been transported, the whole space can be thoroughly cleaned and disinfected, exactly the same as in the operating theatre. In both cases, a number of different loudspeakers are used – from the classic mid-range speaker to magnetically shielded products and enclosure-less models, usually installed behind a dirt-proof cover. The exact products used are application specific because our customers are responsible for meeting medical requirements and we supply the necessary equipment.

From a purely acoustic point of view, what is the most important thing about medical equipment?

At home, if I aim my hi-fi speakers directly at myself, they sound different from if I turn them through 45 degrees towards the wall. We check that here, too. We measure whether the loudspeakers emit much wider sound in a certain direction or too much sound to one side. To do this, we need to make sure that the sound from the back of the monitor also reaches the front. This sounds logical, but it's not easy when the speakers are installed in extremely restricted spaces. Space is at a premium everywhere.

What are the challenges for installation?

It all starts with the choice of materials. We do not use the paper diaphragms that provide such good sound in your sitting room hi-fi system but would never hold up in the operating theatre. I have already mentioned the covers for protection and hygiene reasons. In some equipment, a cover is placed in front right from the start, which has an extreme effect on the sound quality, we then have to take this into account – for example, by including different sound filters.

How do you work with customers?

We are happy to work with detailed requirement catalogues or we supply a suitable loudspeaker and recommend our own installation criteria. Something we experience not only in medical technology: the issue of acoustics is not even thought about until the very end, and the device has been completed without us being involved. Then we have to optimise the sound in retrospect but this is one of our strengths, because we can always find special solutions for every condition. In our test laboratory we are able to test built-in loudspeakers in all bandwidths and installation situations in detail. But ideally, we prefer to plan together with the manufacturers.

What direction is loudspeaker development in the medical sector heading?

I find new ideas regarding patient well-being that generate relaxation through purely acoustic signals really exciting. We have worked with a manufacturer of "white rooms" who aims to reduce tension in people throughout the room through images, sound and various other measures. That was very interesting. At a technical level, the main focus in loudspeakers for some years now has been on making them smaller and lighter, which helps to achieve smaller installation dimensions. This has become possible with state-of-the-art materials.

What materials are they?

Speakers usually contain ferrite magnets, which we can replace with neodymium models for small speakers. Thanks to their extremely high magnetic energy, we can use much smaller ones. However, neodymium is one of the rare earths and is significantly more expensive than ferrite.