Making music begins with the formation of a tone. For example by bowing a string on a violin or blowing on a reed of an oboe. The tone of an organ pipe is caused by the oscillation of the flowing wind on the upper lip of a pipe. The surrounding air comes in vibration and makes the tone. The string carries the vibration to the violin and let it resonate with the tones and the overtones and that causes a reinforcement of the tones. The same thing happens with the vibrations of the reed in the oboe. The air column in the pipe of the oboe resonates on the vibration of the reed. The air column in the organ pipe is also resonating by the tone, that was originated at the upper lip.

Reinforcing this resonance gives the sound more dimensions, the vibrations are spreading in all directions, they fill the space. The music is full transferred to the listeners. The sound waves of the music instruments bring the surrounding air in motion, they repeat the reflections by reflecting them against the walls and a good acoustic let resonates the entire room. At each reflection some energy is lost, slowly the force decreases until the sound dies out.

Music cannot sound in an acoustically dead space. Resonance is the most important factor of making music, the experience of music is only optimal when the whole room is resonating, which only can arise if the room has good acoustics.

Centuries ago as people built houses in relation to the length of their body, they gave churches exorbitant dimensions. Often, building was a long time of working and generations passed by before this gigantic work was finished. But they found the target of great importance; the choir received a great response through this extreme acoustic conditions. The entire room was filled and gave the song a heavenly glow. Sounds with these dimensions let climb the musical emotions.

Room with good acoustics

It is impossible to put a large orchestra in a living room. However a CD of the Orchestra can be overheard in a living room. The wonderful acoustics of the concert hall is recorded along with the sound of the orchestra on the CD. A simulated concert hall is created in the living room, where the acoustic conditions of the sound of an orchestra are available. The volume is now proportionally adapted to the small room.

Churchorgan and acoustics

As well as an orchestra a church organ takes the reverb of a good and spacious acoustics; it constitutes an unbreakable unit. For some organ builders it is a reason to never build any house organs. How fantastic the organ in the church may sound, outside this space it is lost. The organ sound has shine and brilliance, but that can only be heard if a room with good acoustics creates an opportunity to develop these properties.

Radiostudio with acoustical hall space

In the radio studios the engineers have special hall rooms, large empty spaces in the basement of the studios. If they need more reverb they send the sound from the studio to the echo room. The reflected sound, completed with the hall comes back via microphones in the studio. Through the additional acoustics the sounds resonate now freely in the room and that makes the listening more pleasant.

From time to time I made an audio recording of my pipe organ at home and let it send from the studio to the echo chamber. When I overheard the results it sounded as if a church was added to my living room. I have always regretted that I could not permanently have this reverberation room.

Physical process

Reverberation is a physical process of multiple sound reflections in a large room. To analyze exactly what physical process happens, a scientist can test this in a lab test by executing a similar physical process. In simple words: sound is converted into electrical energy and sent over parallel delay lines with different runtimes. If necessary, the process can be repeated several times. This creates multiple reflections and repeating this process corresponds to the multiple reflecting against walls.

Lexicon MX 300

In a church the organ sounds reflect against walls, pillars and vaults with different distances from the organ in a church and there are multiple reflections, suffered different runtimes. Each object in the room affects the reflections. They multiply the reflections, they give different directions, they urge new reflections. In the Lexicon MX 300 it is simulated by using large number of delay lines with different runtimes, which have no arithmetic relations mutually

Operating instructions for the Lexicon MX 300

There are a variety of different types of hall in the Lexicon MX 300. Not only by the differences in the size of the simulated rooms, but also the characteristics of the acoustical behavior. Size and properties are here variable parameters.

The sounds from the DAC (Digital to Analog Converter, also called the sound card) go directly to the front speakers and parallel to the Lexicon. When the DAC hasn’t two parallel outputs, a splitter can create two channels.

The outputs of the Lexicon go to two active speakers that are placed in the vicinity of the console.

With the large knob on the right side the desired reverb can be selected. No. 1 Orchestral has always too much hall. The second reverb: Small but Large is suitable well. The somewhat unusual names are attributed to the American sense of humor; there are also Fan Tastic and Smallis Hallis.

Turning the knob makes the name visible, pressing it activates the desired reverberation. With turning the knobs A - B and C the selected reverbs can be adjusted.  A is delay (delay), there is no need for, put it to zero. B is to adjust the reverb time and C is to expand the size of the reverb room. C can change the properties of the reflections also. With at least thirty kinds of hall there is a large choice.

The knob most left is the volume of the hall, the LEDs may light up green; if they are red the signal is too strong. The Lexicon has possibilities which are not of importance for Hauptwerk, Page select is one of them. If this is pressed accidentally, it can be reversed with exit. Bypass sends the signal directly, without any reverberation to the exit. It is an useful button to compare fast the sound with or without reverb. A comprehensive English user manual is supplied with the Lexicon, but users can find intuitively all the ways he would like to apply.

Compromises between Sound and Hall in the samples

The hall that was stored together with the sound in a sample, is heavily dependent on the place where the microphones have been placed in relation to the organ. Dry samples are sounds that have been recorded in the vicinity of the pipes, they play the pipe sounds very detailed. At a greater distance, the balance has shifted from direct sound to a sound with more reverb. There is always a compromise between the two kinds of sounds.
There are also sample sets offered with two recordings per pipe, which were recorded with different distances. The organist can even adjust the balance between the two kinds of sounds. More hall gives the sense to be forced to a larger distance of the organ. In the church, the organist is located close to the organ and he hears the hall of the surrounding acoustics of the church. That is to play the best experience in the Church.

With the Lexicon it can be reached without compromises. The direct sound of the pipes on a short distance and reverberation to the extent that the organist can find suitable for the music that he plays on this moment. A spacious hall makes a speaker in the church inaudibly, and also a melodic line in the music is not transferred. Then the reverberation must be limited. In contrast to the sound of a fully cheering organ, it comes more into its own with the acoustics of a cathedral..

Hall of the Lexicon goes beyond the Hall of the samples

The excellent reverb from the Lexicon exceeds the Hall which is rendered by the samples. The sense playing a church organ is experienced as more realistic. The use of dry samples plus the hall from the Lexicon shows it best. Also the samples with little reverberation, because the acoustics of the church not provided, sound noticeably better with the Lexicon.

As an experiment I have removed the reverb-tails of a sample set with much hall and added the hall of the Lexicon. It proved to be a better reproduction of the organ and it is an advantage that the hall is now fully adjustable. Several organists have played my organ and also they found that a church organ was better represented.

Lexicon MX 300

The Lexicon MX 300 can create several acoustic spaces of various sizes. The choice is  sufficient to add an appropriate reverberation time to different sample sets. The acoustics in the Lexicon MX 300 can be chosen from many areas of different sizes and different orientation, such as hard or soft walls, many or a few reflections, widely scattered or more focused. These effects are adjustable infinitely. The acoustic properties of an almost unlimited number of churches are achieving in this way.

Pressing a chord and wait more than 20 seconds until the last reflection is extinct, may never need. But the Lexicon can make it with the first option Orchestral (large hall), if all parameters are set to the maximum. More practical is the option Small Hall, which deals the missing acoustics in a church as in Anloo (in the north of the Netherlands). Only a short Hall time which is do not turn the small church into a cathedral. Selecting the acoustics of a large church, it is still not unnatural, but the organ seems to have moved to this large church.

Nature of the Lexicon reverb is more consistent with reality, as the hall which was sampled together with the sound. The organist hears the organ in the church on a short distance and suffers the effect of the dying sounds in the acoustics. He can hear oriented, opposed to a microphone in the place at the console.

A sample created with a microphone close to the organ reflects the sound in detail, but will deliver little of the reverberation. This reverberation is audible in a sample recorded at a considerable distance from the pipes is, but that comes at the expense of the detailed sound of the pipes. The organ seems to be moved on a greater distance of the organist. The direct contact needed to control the music is lost. Sometimes, two samples are recorded at the same time with different distances from the organ. The organist can choose himself the balance between them.

Convolution Hall

The most realistic form of digital acoustics is obtained with convolution hall. A digital copy of the acoustic effects of a large room is stored in a memory. The sounds that passed by this memory undergo the same effects. At the moment it is still a fairly expensive system; about 1200 to 1500 euro. 

The Lexicon MX 300 is approaching the convolution hall in a realistic way. I have compare them on a Hauptwerk organ and find the audible difference is only small. A Lexicon MX300 is available for 289 Euros in the Hauptwerkshop

There are various reverb devices (Alesis) or programs (Reaper) for sale, which simulate the hall in a simple way. They are cheap and the result is bad. This reverb is not similar to the complicated processes that provide a realistic reverb in the Lexicon.

   auf Deutsch