1. The Company

 

1.1 A musicians vision 

 

When you hear an acoustic live performance, you experience the room as well as the sound of each instrument.  At the same time as you hear every detail, you hear the “whole picture” of the orchestra or band.  Sound that is pure, clear, spacious and powerful. Expressing all kinds of emotions without distortion, unnecessary resonance or coloration.

 

”What if there was a loudspeaker, that could reproduce sound the way you would hear it live.”

 

1.2 About our company

 

Intelligent Sound (IS) is a Nordic joint venture that has developed, manufactured, marketed and installed sound equipment for many years.

IS product idea is built on research and development around sound and loudspeakers, that dates back to the 70’s.

In the last few years we have supplied loudspeakers for recording studios, professional musicians, concert halls, churches, schools, restaurants, industrial and other environments where our customers have very high demands for quality and performance.

1.3 Our mission

 

The loudspeaker’s primary function is to give you the most accurate possible experience from a recorded and edited sound source.

When a loudspeaker is not capable of reproducing sound so that our ears find it natural, when the loudspeaker takes away or adds information in the form of distortion, masking or resonance etc. it results in the loud speaker ”absorbing” parts of the information that should otherwise have reached our ears, making the sound experience less than desirable.

This is normally referred to as ”distorting”, ”coloring” or ”masking”  the sound.

With this in mind, the ambition of many loudspeaker manufacturers has been to create neutral loudspeakers, free of these phenomenon’s  and capable of reproducing the sound source, as accurately as possible.

 

Over the years the market has seen a number of different theories, and an even higher number of different technical solutions. And yet no one has managed to get close enough to total accuracy, leaving speaker buyers facing a big dilemma, having to choose between loud speakers well suited for classical music, pop/rock music or speech, but rarely all types of music, this of course being the ideal solution.

 

The main reason the market has not been able to offer a loudspeaker that can reproduce the sound, so that your ears will experience it as a natural sound, is that no one has managed to build a loudspeaker which reproduces sound in the same way as the natural sound source would.

Our goal has been to create a completely neutral speaker that reproduces the sound from a voice or an instrument, with total accuracy.

 

To be able to reach this goal, we had to find a new way of thinking, set old theories aside, and take a whole new approach. Because of this, we have found solutions to different “sound problems” which most experts said were impossible to find.

 

We call the result of our development: Loss-less Audio Reproduction (LAR)

 

2. Sound

 

2.1 What do we mean by ”sound” ?

 

All sound carry information, and also details about the sound source.

All sound sources sets air in motion, by producing pressure waves and a lot of the information we receive only consist of sound impressions.

2.2 What happens around a sound source?

 

A natural sound source, like a human voice, a bird, a waterfall or an acoustic instrument, spread continuous and uniform information about itself. The sound spreads in all directions and with varying tonal balance (the relationship between bass, mid range and treble.)

One example of this we can hear if we compare the sound in a room where we are, listening in front of, or behind, respectively, a guitar player playing and singing.

 

2.3 How our hearing and brain work together

 

As the human race has evolved, we have developed a greater sensitivity to frequencies between 50 and 5000Hz. Between these frequencies, most information like speech, song, animal sounds, warning signals etc; can be found.

This high sensitivity makes it possible for us to identify very fine details in the sounds, which surrounds us, and makes it possible for us to distinguish between things, which have very similar sounds.

Even in a noisy environment, we can take in information, if we concentrate on listening.

As we hear a sound, the brain separates the information that is relevant, from what is not, and our ability to do so, is a key part of our defense system, as different warning signals must be understood in any environment.

 

2.4 Hearing loss

 

Our ears can more easily distinguish between different details in the sound at lower sound levels than at levels exceeding 95 dB. One reason for this is that the ear protects itself against overload at a high volume. When the sound level at certain frequencies becomes too high, the eardrum reacts by contracting and sending a signal to the brain –  “my ear hurts!”.

 

The result of a contraction of the ear drum is that our ability to detect small details in the sound, decreases radically, and that our defense system reacts by trying to get us to stop the painful sound (to cover our ears, to get out etc). But as we are the “masters” of our own bodies, we sometimes ignore these warning signals, and choose to remain exposed to an excessive noise level,  putting ourselves at great risk of hearing loss.

 

2.5 Sound orientation

 

As we listen our brain gets information from two points at the same time, our ears.  The angle formed by the straight lines between respective ears and the sound source uses the brain to locate the sound source in relation to where we are ourselves located.

 

Registering and learning the sound has much in common with our eyes way of registering information. In both cases we get three-dimensional impressions, that for example enables us to locate where the different instruments are placed on a stage in relation to each other, horizontally, vertically and depth wise.

 

2.6 Sound library

 

The ear is one of our most flexible organs and is especially important for our ability to orientate ourselves in our sound surroundings. All sound sources set air in motion and produce pressure waves. Much of the information we receive only consists of sound impressions.

 

We can see the interesting fact that nature has made it impossible for us to “close” our ears, as an indication of the importance our hearing has to us.

 

From early childhood we learn to recognize different sounds and we start to build up a sound library in our brain.

The brain’s library builds up during many years of experiences from the sounds from our environment. Already as infants, sounds will catch our attention and we try to understand what the sound is, where it is coming from and what it means. We associate both thoughts and emotions with the sound we hear and store them accordingly in the experience in our sound library.

 

Our personal library reflects the type of sound environment we have experienced so far and it constantly adds new sounds to it. We can just by our hearing analyze what is happening around us without having to see it, and actually not even having to give it a conscious thought.

When sound reaches our ears, the result is compared to the contents of our sound library. Our logical and emotional reactions depend mostly on previous experiences that can be associated with the sound.

 

A loudspeaker must be able repeat the sound source in a way that our own sound library can easily identify and relate to it.

 

2.7 What is acoustics?

 

We distinguish between sounds coming directly from a source, such as a voice from the indirect sound that is reflected from ceilings, walls and floors.

 

Acoustics means the resonant sound that occurs after a sound impulse. Resonant sound is a combination of how sound bounces (reflects) and how it is dampened (absorbed).

A long resonant sound occurs for example in an empty sports arena, in a church or in an enclosed stairwell.

 

2.8 How do we function together with acoustics?

 

Acoustics is a phenomenon that constantly surrounds us both indoors and outdoors.

 

Providing that the acoustics doesn’t give a long resonance (more than 4 seconds), it is of very little importance to our sound experience. This is because the brain expects acoustics to be there and quickly identifies its character, and helps us to ignore it. This means that we can focus on a natural sound source even in an undamped room and understand what is said. If this is to function with the help of loudspeakers carrying the sound, the speakers are required to reproduce the sound in the same way as a natural sound source would.

 

3. Test methods

 

The technology commonly used by speaker manufacturers, for measuring sound characteristics, dates as far back as the 1930’s, when the technology to measure unwanted sounds in industrial environments, was developed, in plain language: how to measure noise.

This technology is sensitive to the positioning of the test microphones. A small change in position can result in  big variations in the test results.

Surprisingly enough the same method is still being used today, but with more modern technology.

 

This way of testing has nothing in common with how a human ear hears.

That is why Intelligent Sound has developed a method to measure the desired sound, as opposed to the noise, in stereo-surround.

We measure the sound image that appears between and in front of the speakers.

 

3.1 Traditional test methods

 

3.1.1 Which values are measured?

 

Resonance in the loudspeaker cabinet, frequency response, image width and impedance.

 

The resonance time is measured by feeding sound into the loudspeaker, and measuring the time it takes for the sound to drop below a certain level.

 

With the front of the loudspeaker facing the microphone, the frequency response is measured.

 

By turning the plate so that the loudspeaker rotates around its own axel the image width can be measured.                                                                                           

 

Impedance is a unit to express resistance, measured in ohm. It shows how much load the loudspeaker puts on the preamplifier. Low impedance puts a negative load on the amplifier.

 

3.1.2 How do we measure?

 

A loudspeaker is mounted on a rotating plate.  A measuring microphone is placed at a one-meter (three foot) distance from the plate, measuring the sound at the center of the loudspeaker.

 

3.1.3 How do we account for these results, and what do they tell us?

 

Resonance times are measured in seconds, and tell us how much resonance there is in the loudspeaker cabinet. The time it takes for the sound to disappear in the speaker cabinet. Time perspective is often very small as the cabinets are usually small.

 

Frequency response is shown with a diagram. This gives a partial picture of what the loudspeaker sound like, as the sound leaves it.

 

When the image width is measured we get several circular diagrams where one can see how different frequencies travel, both horizontally and vertically, from the loudspeaker. This is done to express how the speaker should be positioned, to reach desired parts of the room.

 

3.2 How does Intelligent Sound perform the tests?

 

TEM – A unique test concept from Intelligent Sound.

 

Intelligent Sound is the result of new thinking in the field of sound testing.

The method we have developed is called TEM, Two Ear Method.

 

3.2.1. How did TEM originate.

 

It started with a few of us musicians being tired of the fact that the information which was delivered from our instruments, was not reproduced in a realistic way through the loudspeakers. A great deal of the information that we knew reached the amplifier, such as drums, guitar, vocals, bass, sax and so on, was lost on the way to our ears. This made us start to think about possible reasons that could create this phenomenon. The traditional methods for measuring sound turned out to be far too limiting, so we developed a new method for measuring sound in a way that was more realistic our ears.

 

We started out using the way our hearing works as a reference point, and from there proceeded to try different ideas, and this led us to possible solutions, on our journey towards the true sound experience.

 

3.2.2 How does TEM measure?

 

With TEM the sound is always measured from two loudspeakers simultaneously in a ” free space”, against nothing but the floor and the back wall, where we have complete control over the entire sound within the loudspeakers combined listening area.

To make this possible, we have developed custom-made test equipment that “listens” in the same way, as people would do, with our two ears. That’s why we call it the ”Two Ear Method”.

 

3.2.3 What does TEM measure?

 

TEM measures the loudspeakers ability to gather all the information in the signal from the preamplifier, and how they reproduce and develop the sound image that two or more loudspeakers create, for Hi-Fi (sound/music listening), Surround (sound and picture combined) or PA (loudspeakers for auditorium) use alike.

 

TEM processes the sound in all its three dimensions, height, width and depth.

 

3.2.4 How do we account for our TEM test results?

 

We measure throughout the entire listening sector that the loudspeakers together create, and then account for the lowest values in front of the listening sector.

The most common opening angles range between 60 and 95 degrees seen from the front of the loudspeaker. Our results are therefore very exact and this way we can specify how the sound from our loud speakers is presented.

We show the deviation from the average value in decibels (dB).

3.2.5 What is the result of TEM?

 

Through the development of TEM we can build loudspeakers where we have total control over a number of different parameters.

Thanks to our control over Phase, Frequency and Amplitude we can achieve an exact reproduction of the incoming sound signals, which means that the sound becomes uniform when it leaves the loudspeaker, and uniform as it reaches the ear.

 

Phase: Unison performance between the different elements, or that they go in exactly the same direction at a specific frequency.

Frequency: How fast the element moves

Amplitude: How much the element moves, shown for the different frequencies 1/3 of an octave.

 

We have accomplished a way of conveying the sound signals, the same way as they are presented from a natural sound source.

 

3.2.6 IS unique sound qualities

 

As we perform testing on a model or prototype of a speaker, the TEM test equipment gives us full control over the sound that comes out of the loudspeaker. With these test results as a foundation, we can design an effective crossover filter. This means that we get information that enables us to, in our filters, control electrical, electro-acoustic and mechanical crossovers between elements and therefore avoid overlapping frequencies (peaks), masking effects (loss of information) or protruding frequencies (resonance, distortion etc.) which all would remove information from the sound source.

 

Example:

 

A woofer’s natural frequency is variable. This means that some frequencies are amplified, while others become weaker. The amplified frequencies place themselves “on top of” the frequencies above them and create a masking effect. This causes a great deal of loss of the information that came from the source. If we look at frequencies in the 80-400 Hz range, they can effect the whole sound image, as all of the amplified frequencies affect the experience, to some degree.

When the lower frequencies overpower the mid-range, the sound will be perceived as fuzzy, dull and unclear, or in other words: not enough treble.

 

3.2.7 Spreading diagram

 

The sound from IS gives you a broad listening sector, and within this sector the technical specifications will always meet or exceed the specifications given for each loudspeaker model.

 

Outside this sector we get a gradual reduction of linearity but the information value in mostly maintained. What listeners will notice is that the treble becomes somewhat weaker outside the primary sound image but the sound is just as clear and distinct.  

 

3.2.8 Overlapping sonic fields

 

The part of your listening area that lies inside the field where the sound images from the two speakers overlap each other, is the area which is the optimal for the listener (the shaded area in the diagram). In this listening sector the stereo perspective is very distinct and the ”space feeling” from the recording is experienced in a realistic way.

One can simply express this as that ”one experiencing the feeling of being present in the recording studio”.

3.2.9 Frequency range

 

Frequency range expresses how deep down in the bass range and how high up in the treble range the loud speakers can go.

 

3.2.10 Frequency response

 

We measure signal response between 32 – 20.000 Hz. The deviation in the frequency range is noted in 1/3 of an octave in amplitude and is expressed in Db’s.

 

[Frequency curve for our model Double 8]

 

4. IS Loudspeaker technology

 

4.1 Crossovers

 

In the audio business, it is often said that: one crossover frequency is the ideal solution. One of the reasons that one crossover frequency is preferred is that there are often problems associated with phase shifting and/or overlapping at a crossover frequency. This type of problem creates the common conception that filters should have as few crossovers frequencies as possible.

Two crossover frequencies, can occasionally work well, while three are usually avoided, as more problems occur in this case.

 

The crossover used in Intelligent Sound’s loudspeaker is our own unique design, which enables us to have a crossover frequency for each element in our loudspeakers. IS presently builds loudspeakers with up to five crossover frequencies, which enables us to optimize the combination of elements and cabinet, and make full use of the whole speaker construction.

 

In our four-way filters, the characteristic ranges between 6dB/octave and 48 dB/octave. The results depend on where the test is performed. We exclusively use components that give the right  q-values for the filter. The final inspection of the filter gives divergence value for the loudspeaker in phase+level of less than 0.5dB SPL  from the filter).

 

4.1.1 The crossovers relationship to the amplifier

 

Amplifiers with a very high damping factor affect the  q-values in the filter differently than amplifiers with low damping factors do. The sonic differences that this results in are unacceptable. To compensate for these differences, we have used a thin cable solution in certain parts of our filters, which means that a preamplifier with a high damping factor, will only have a marginal effect on the q-values in the filter. This also means that even an amplifier with an extreme ascends time, will function better and become less unstable.

 

Conclusion:

 

Due to our crossovers unique technical solutions, amplifiers with high or low damping factor will only have a marginal effect on mid-range or treble.

 

For bass loud speakers the following applies:

A high damping factor can have a negative effect on the loudspeaker as the resonance phenomenon, which IS desirable for the bass element, is damped. This reduces ”bass output” and can give the speaker a tight and hard tone (this is true for all types of speakers). In a hi-fi setting, a damping factor between 50-200 is preferred, while for PA system, a higher damping factor is preferred to control the bass element in the most favorable way. This gives better protection against damaged speakers, due to overload. If the sound is “tight”, an equalizer will solve the problem.  All you need to do is to increase at the 63-octave.

 

4.2 Fuses

4.2.1 Glass fuses

 

In traditional loudspeakers the elements can easily be damaged through overload and, worst case scenario, the damage can be so severe that the element has to be replaced, causing the speaker to be out of commission, not to mention the repair bill it can create.

 

To avoid these headaches, all of our loudspeakers are equipped with glass fuses, to protect them against overload. The fuses are mounted on the back of the cabinet. Glass fuses provide a reliable protection against damages caused by overload.

 

In case of overload, the fuse “shuts down” the sound, preventing any damage to the speaker. After replacing the fuse the speaker sounds as good as before.

 

4.2.2 Active fuses

 

When using our loudspeakers for PA setups, (concerts, events etc) we can offer a unique solution, an ”active fuse”. An exclusive solution from Intelligent sound, to prevent damage to speakers, or interruptions during a show.

 

Our active fuses are mounted inside the speaker cabinet, and this is how they work:

In case of overload, the sound level is lowered by 3 dB. If the sound technician disregards this warning, the sound is switched off for 2 seconds. After the silence the speakers start up again, but if the volume has not been reduced, the fuse switches them off again. The fuse will continue this procedure until the sound technician lowers the volume. IS active fuses are designed to activate this safety measure automatically, and this feature gives the loudspeaker an effective protection, and makes sure that damage by overload damage will be avoided.

 

The protection that you get from our active fuses will ensure a long life expectancy and the highest reliability.

 

4.3 Loudspeaker elements

 

IS speaker elements are modified to be give an optimized performance, when integrated with our with our filter solutions.

 

4.3.1. Bass reflex

 

Our speakers cabinets have a front facing opening, that serves as a “tension spring” for the bass element, which thereby gets exactly the right resistance as the different bass tones are played, which allows the speaker to perform at both lower frequencies and at higher volumes, than the cabinet would otherwise be dimensioned for. The openings forward facing position, helps the speaker to control the timing of the sound, and gives sonic clarity at lower frequencies.

 

4.3.2 Insulation

 

The insulation materials used inside the speaker cabinets are the commonly used: foam or styrofoam. This will absorb excessive energy in the cabinet, leaving the sound crystal clear.

 

4.3.3 Internal wiring

 

We use custom made cables for internal wiring, ensuring the best possible signal transfer. The cables use 4X1,5 mm pewter/solder plated copper wires.

This enables us to build speakers that will sound good in any environment.

 

4.3.4 Materials used in the speaker cabinet

 

We select the materials, soly based upon what will give the best possible sound. When a design is finalized, it is extremely important that we maintain the exact material specifications for as long as a model remains in production. Any deviation from the original specs. will have a drastic effect on the sound,

In our current product line, we are using a 15-20 mm thick Asian pressed hardwood, that offers an extremely good combination of characteristics such as hardness, porousness and weight, as well as being just as rigid as it needs to be. The material carefully chosen for the cabinet, will not take away from the sound experience.

 

4.3.5 Bracing of the cabinet

 

In our larger speaker cabinets, we mount horizontal supports to minimize the cabinet’s influence on the sound. Evenly distributed on all sides, we have either 45 or 90-degree blocks as braces, but also to add turbulence for acoustics inside the cabinet. Bracing the cabinet contributes to the sonic qualities of the speaker, and eliminates that “I-am-listening-to-a-box” feeling.

 

5. Conclusion

 

5.1 Sound reproduction through Intelligent Sound’s loudspeakers 

 

Intelligent Sound’s loudspeakers reproduce sound in the same way as real sound sources do. The sound is integrated when it is sent out from the loud speaker, and the sound from two or more IS loudspeakers integrate and create a sound that you will find very realistic.

Even the sound reflected from the ceiling, walls or floor is very true to the original sound source.

 

IS loudspeakers will give you a sound that is crisp, clear, distinct, spacious, powerful, that can express any feelings, without distortion, unwanted resonance, without masking or coloring. They are capable of recreating the sound experience in a way that makes you feel as if you were present at the actual moment it was recorded.

 

5.2 Loudspeakers and acoustics

 

Our loud speakers work very well together with the existing acoustics in the room. The sound from the loud speakers is so exact that even if it is reflected from the ceiling, walls or floor, the sound is easy to embrace. Even in rooms with ringing echo the sound system can be appreciated when using IS loud speakers.

 

5.3 Choosing the right size speaker

 

Select the speaker model that is right for you, based on the cubic footage of the room that you will fill with music, and the volume level that will suite your needs.

 

5.4 Good sound environment 

 

The sound from IS loudspeakers will provide a good sound environment that is relaxing for your body and your soul.

As your ears will experience the sound from the speakers as natural, you will not have to strain them to interpret and enjoy the sound.