In Search Of Perfect Sound: Aleks Kolkowski & The Denman Horn

Throughout the past century, recording processes in music have changed drastically. Prior to the introduction of multi-track recording, all recordings had to be fully mixed together in one live performance. If one musician was to make a slight error, the whole process would have to be redone. In this digital age that we live in, the requirement for physical formats has been rendered obsolete by computers, iPods and streamlined technology. But for some reason we still we favour the aesthetics of the technologies of yesteryear.There’s a growing spark of interest in vinyl with international sales figures spiking with record stores enjoying a similar renaissance.

A new art installation at the British Science Museum in London titled ‘The Exponential Horn: In Search Of Perfect Sound‘ explores the relationship between digital and analog sound. The centrepiece of the installation is the ‘Denman Horn’, the UK’s largest horn loudspeaker. The colossal structure measures 27ft in length with a 7ft 1 inch square horn mouth. The aim of the project is to give visitors the opportunity to experience an important milestone in the scientific quest for perfect sound. The horn itself is a redesign of an original, which was commissioned in 1929 and was a popular highlight of the museum until being accidentally destroyed in 1949. Rebuilt over a period of eight months by the Science Museum’s Workshops team, the 12mm thick fibreglass horn features a 9ft section of the original object which was made from a much heavier metallic alloy.

The head of the project is Aleks Kolkowski, a composer and researcher who uses obsolete media, historical sound recording and reproduction apparatus to make new forms of music. Through performances, installations, recordings and live historical re-enactments his work invites people to listen to the present through the audio technologies of the past. We paid a visit to the Science Museum to meet with Aleks, experience the loudspeaker first-hand and discover whether or not there is even such a thing as perfect sound…


To begin, could you explain the basic concept of how the exponential horn works?

The exponential horn is a product of science and technology in the 1920’s, which was the first time there were any scientific theories evolving around the physics of horn loudspeakers. Scientists discovered that building an exponential horn (one which curves rapidly with length) was the most efficient way of handling sound energy. What you have at the narrow end is a very high pressure, which has to transform from high pressure, low velocity energy to low pressure, high velocity energy at the other end. This is called an impedance matching system. In order for the exponential horn to produce really low frequencies, it has to be very long and that’s why this one is 27ft in length. Some people mistakenly think that horns are built to amplify sound. They don’t amplify, they manage energy in a way.

This horn was designed for a new kind of compression driver which was designed in the Bell Laboratories and produced by the Western Electric Company. Another thing about the driver is that it has an electromagnet with a 7 volt power supply, later they were replaced with a permanent magnet. We had to build a dedicated power supply for this horn.


“The Truth About the Science Museum Set” October 19, 1929 © Amateur Wireless

In terms of the audio-in, does it come from a digital or analog source?

We use both analog and digital sources but we’re using an analog tuner for the digital broadcasts. We found that we were getting a lot of drops from digital streams, I was fed up with that so we’ve got a high-end analog fm tuner which we are using for all the broadcasts. When we run a live show, it acts like a giant monophonic horn. We’ve done it with live bands, spoken word events and even modular synthesisers.

Compared to the original model, have you improved on it or is it a re-creation?

In terms of improving on it, the driver is from c.1930 & the first nine feet of the body is part of the original horn. We’ve just built onto it with the same specification. The original was made out of a lead and tin alloy. They would have covered it in a quarter inch of pitch and then wrapped it round with hessian to deaden the horn and prevent it from resonating. We made our horn from fibreglass partly because the Science Museum Workshops had experience working with the material here and partly because we could make it thick enough to avoid resonances.

It was originally installed over a door in the middle of the gallery, that must have run into all sorts of problems and required acoustic treatment to the gallery space. The same thing is happening here, because the museum are very keen that it’s accessible to the public, that they can see it so they will go in and listen. We haven’t been able to close it off to acoustically screen it. When you’re directly in front of it, the horn sounds perfect, but once you go off to one side it changes dramatically, you can just hear it bouncing off the walls, which isn’t ideal by any means.




Whats the widest frequency range that the horn can achieve?

In terms of frequency it can achieve down to 32Hz, and up to 6Khtz in range but when we played test tone records through it, we detected frequencies as high as 12 Khtz, so it’s actually quite extraordinary that this old driver is capable of that. As recording techniques developed, it was found that the demand on these drivers was too much because there was a lot more bass and high end sound. That’s why sound systems were split up into different components for different sound ranges. This is an all in one component and still considered to be one of the best loudspeakers ever made.

Could the technology used in this horn be used to play sounds to wide open spaces such a a festival?

We don’t play it at extreme volumes, and we have to be careful with it because it’s a piece of the museum’s inventory. Theoretically you could but you would need limiters or high-pass filters in place to ensure not to damage the driver. We played Led Zeppelin’s ‘Whole Lotta Love’ and the middle section was just too heavy, but then again we’ve played big orchestral pieces, electronic beats and even a Techno record through it and it’s been fine at low volume. I’m amazed with how it’s coping with all types of music.

It’s clear that this isn’t about volume, it’s about clarity but also imperfection.

It’s imperfect in a way that I find interesting. The extreme directionality, for instance, means that you have to be within its zone to experience it properly. Outside of this, you hear it reflected off the walls. You are being drawn to listen directly in front of the giant horn mouth and it can be very arresting once you discover the right place to hear it – much like finding the perfect view of something.

To speak on electronic music, there has been a peak in vinyl sales in the past couple of years, where do you see sound formats and sound in general in the future?

Who knows? We had a group of guys called FISH Innovation in to visit who had developed an iPhone case which increased the volume of the phone’s internal speakers. It’s based on a Paul Voigt Corner Horn and there’s a direct connection to the technology at play here. This is a 1927 driver and a horn from 1929 and still people are coming in and getting a lot of enjoyment out of it. It’s quite extraordinary that we’re in a time where it seems every single piece of historic audio technology is coming at once. I can imagine a lot more interplay between the analogue and the digital – similar to what we are doing in this installation.




The name of the exhibition is ‘In Search of Perfect Sound’ is there even such a thing as Perfect Sound?

The title refers to Roderick Denman who designed the horn and his quest for perfect sound. I think there is perfection in imperfection. It has to be rounded off in a way that if you get an enjoyable experience and love what you’re hearing, then that’s perfect. If something was perfect then there would be no room for improvement so it’s the listener that makes it perfect in this case.

How long did the project take to bring together?

I first proposed it in 2012, during my residency as sound artist here at the Science Museum and this is the final outcome of that residency. It was also based on research from the Museum’s current Curator of Communications John Liffen, who had done research on the horn. He actually found the initial section of the horn hidden away in a disused room at the back of the museum in 1981. Until then it was thought that the horn had been destroyed in a building accident in 1949. John showed me his research and I proposed the project to the arts team here. The Museum’s Workshops team threw themselves into the building project and it took them 9 months to complete. We had to go through old newspaper archives to find photographs of what the horn used to look like. They worked from these combined with the original specifications.



What sort of events programming are you running alongside the project?

Every second weekend there are live events, we’ve had students in from the royal college of music, live radio-phonic works. The science museum have a great collection of old gramophone records which we’ve been playing there’s lots of technical records for demonstrating types of radio interference and unusual things like that.

What’s your next project in sound going to be?

It’s going to be another historical sound project, this time around the corner at the Royal College of Music. We’re going to re-enact one of the earliest attempts to record a complete symphony – in this case the legendary 1913 recording of Beethoven’s 5th by the Berlin Philharmonic, conducted by Arthur Nikisch. It was special because it was the first time that they started to use a full orchestra in the studio, we wanted to see how it was done. It’s going to be an entirely acoustic recording using Wax Disks which were the recording media used until the 1930’s. It’s a research project so the aim is to approach with the same musical style and technology (as far as we are able) and see if we can recreate the conditions and record it in front of a big horn. So it’s another horn project!

The Exponential Horn: In Search Of Perfect Sound is on display at London’s Science Museum until 27th of July. For more information and a wide programme of events running alongside the project see here. 

Interview: Conor McTernan