Equator Room Analysis Software
Each equator Q Series studio monitor is upgradeable via the USB connector on the back of the amplifier panel to utilize The Equator Room Analysis software featuring Secondary Reflection Correction (SRC). This is a self-correcting hardware and software room correction algorithm specifically designed to compensate for room response anomalies. Unlike other room correction packages, the software takes measurements of each speaker from the mixing console and makes adjustments to optimize the speaker response for a particular listening or mix position in the room. Stereo, 2.1, 5.1, 6.1, 7.1 or 8.2 multi-monitoring configurations can be optimized quickly and saved with the push of a button.
Room Analysis Software
In the past, studio designers and engineers would rely solely on room treatments and simple E.Q.s to obtain a flat, transparent response from their monitors, in an attempt to hear what was actually going down on tape. Live end dead end room designs with bass traps became popular. Third octave equalizers made their appearance and along with the help of real-time analyzers, many engineers learned how to make their studios sound really bad. All kidding aside, making a studio sound good is still an ongoing debate. Nevertheless, there are some facts of acoustics and how the brain processes information which can be utilized to provide superior performance from studio monitors.
The brain can distinguish between the direct, first arrival waves and the reflected waves, given the wavelengths are short enough. This is why a violin played in a kitchen sounds just as real as a violin played in a living room, if you were standing there. Your brain can distinguish between the different environments that the violin is played in. This is because the lowest note of the violin is G3, which is 196 Hz. This wavelength is approximately 5.8 ft. Most of the violin's notes have short enough wavelengths that the brain can separate the instrument from the room. Now play a double bass in those same rooms and you will notice that some of the notes are dramatically different from room to room. This is because the double bass plays from B0 to G4 and B0 having a frequency of 30.87Hz with a wavelength of 36.4 ft, your brain has no chance of separating the direct from the reflected waves. Therefore, the room should be corrected for frequencies low enough that the brain cannot separate the direct from the reflected waves. This will depend upon your room size and we give you the flexibility to choose this for yourself. There is one exception to this rule, when your monitors are placed in the near field right next to your console perhaps with a video screen placed in between them. This creates a sort of mini room, within your larger room, where reflections arrive at your ears rapidly causing dips or even comb filtering that your brain has no chance to decipher. More about this later, for now let us continue with the lower frequency room correction discussion.
In those earlier days when we all went out and bought real-time analyzers and one third octave equalizers, we really thought we were on to something. Finally there was an easy way to EQ the whole system in just a minute or two. After getting everything flat, we fired up the system and rolled tape. To our dismay the result was less than appealing. For reasons already stated, this resulted in destroying the frequency response of the instrument in exchange for a flattened steady state room response that our ears never needed nor wanted. Our goal here is to preserve the integrity of the direct wave of the instrument, so that our ears hear the 'real" instrument recorded. How you handle the treatment of your room is up to you, our job is to enable you to hear what is really on your recording. Therefore, we must correct the room for those lower frequencies and the secondary reflections off close objects.
Room Modes & Boundary Conditions
Lower frequency room problems are twofold; room modes and boundary effects. Room modes are the frequencies that can build up in a room. They are caused by the reflection from wall to wall or ceiling to floor of your studio. They are related to the distance between these flat surfaces. As you walk across your room you can hear the energy build up at points and drop off at others. At those frequencies where this occurs, the peaks and dips don't move, this is why they're called standing waves. Some room correction systems go after one standing wave frequency only. This is not sufficient because your room, most likely, has more than one dimension. Most rooms will have three standing wave frequencies related to the distances between:
1. Front wall to back wall
2. Left wall to right wall
3. Ceiling to floor
The Equator Room Analysis software evaluates and corrects for all three of these major standing waves or room modes. Standard one third octave E.Q.'s arenít up to the task. Their fixed bandwidth, or Q, makes it impossible to properly dial in for the correct shape of the room mode. The Equator Room Analysis software utilizes three fully parametric equalizers that automatically measure the room modes and sets the correct frequencies, bandwidths, and amounts of cut required to correct for each mode at any position in the room. It can also correct for multiple positions in the room, such as, one for the engineer mix location and another for the sofa where the band members are sitting. The software takes care of distance and level differences.
The final lower frequency issue that we need to deal with is boundary effects. If a speaker is placed high into the air and has a relatively small baffle size, the speaker is said to be in 4 pi space or free space. Measurements made on a pedestal in an anechoic chamber approximate the response that this speaker would have in 4 pi space. When a driver is mounted to a relatively large baffle or into a wall perhaps, it is said to be in 2 pi or half space. Half space loads the driver at lower frequencies because for any given amount of energy emitted from the driver, it is supported by a half space boundary that it did not see in a 4 pi configuration which is free space or an unloaded environment. This additional loading on the system results in a 6 dB boost to the lower frequencies. Soffit mounting at the meeting lines of a large wall and ceiling puts you into 1 pi or quarter space, this adds an additional 6dB. Finally, if you place the driver in a corner you are now in pi/2 or eighth space and you get even more bass. The question becomes a complicated one of what distances do we consider large? At what frequencies does this take effect? If you put your monitors on 2.5 ft stands, 3 ft from the back wall, 7 ft from one side wall, and 12 ft from the other side wall, what kind of boundary effect do you have for each monitor? There can be a combination of different effects for each monitor. These boundary effects become a non-issue with the optional Equator Room Analysis software as it will measure and correct for these environments for each monitor individually.
Secondary Reflection Correction
Last but not least is what to do with those early reflections off close objects, like the mixing console or video screens. As pointed out before these reflections arrive so fast to your ears that your brain has no way to decipher it from a direct or reflected wave so the waves simply add and subtract from your instruments recorded sound, destroying the reality of it. It can cause dips in your frequency response right in the critical 800 Hz - 3 KHz range. This can cause vocals to recede into the background of your mix. The loss of this definition in vocal articulation can drive you to boost these frequencies to compensate. Then when played back in an average listening environment or even in another studio, with different monitor locations, the mix will be overly harsh. These reflections can also have a negative impact on the stereo image of your mix. The only practical way to correct this is in the digital domain.
Convolution is a technique now being used to create some of the best reverbs in the world. The convolution reverb takes an impulse response of a space, convolves (the process of convolution) this impulse response with a track resulting in a sound as if the instruments on that track were actually recorded in that reverberant space. We do the same thing with Secondary Reflection Correction, just in reverse. The Room Analysis software will measure the impulse response from the monitor to the microphone location and identify the exact time and character of each reflection that arrives within a certain time limit. Then we cancel them out by convolving the signal with the opposite or inverted reflections. We only want to de-convolve or remove the early reflections. Removing every reflection in the entire room, at the location of your head, it would sound as if you were in an anechoic chamber. Those of you who have been in an anechoic chamber for any length of time know that this is something very unnatural. It is a sensory depriving environment that is very disconcerting to your brain. Your eyes look around and see the walls of your physical space and your brain expects to hear reflections from them.
How you set up your studioís acoustic treatment is up to you, we are just interested in a system that works to provide you with the most accurate representation of what you have recorded.
Secondary Reflection Correction Tab
Internal DSP Controller
Built-in to the amplifier of each equator Q Series studio monitor is a proprietary DSP controller. Specially designed software is used to control the DSP functions creating precise crossover topologies for each Q Series studio monitor. The acoustic centers of the woofer and compression driver driven horn along the Z-axis for each model has been aligned electronically with the controller, making each system a true point-source loudspeaker something we coined Zero-Point Reference.
The power and features of the DSP hardware and software allow for each system to be programmed and tuned at the factory to meet strict quality control requirements. This ensures each system model will be within +/- 0.5 dB of a reference standard at key frequency test points. The DSP and software combination provide parametric equalization with precise control of gain, filter type, filter order, cutoff/center frequency, bandwidth, Q and various other filter parameters which are employed to optimize the performance and sound quality of the Q Series studio monitors.
On the front panel of each Equator system is a visual panel that displays; power protect, communication, volume, limiter and a switch that turns the L.E.D. display off. Also via computer control thru the USB connector, the level of brightness can be adjusted using the supplied software package.
Other features of the DSP Include:
24-bit / 96 KHz, 28-bit coefficients Guarantees high resolution for accurate frequency response equalization at all frequencies.
48 bit inter-stage data word size. This allows filter gains of over unity without clipping or wrap around. Thus eliminating the dreaded digital clipping harshness.
76 bit accumulator. This guarantees low noise filters.
High quality ADC and DACís from AKM giving us -115dBFS performance.
Correction for manufacturing variations.
Dual Threshold Compressor/Limiters per driver enabling multi-band limiters for unnoticeable driver protection.
Precise crossovers designed by importing response data of each individual driver separately and then applying correction to each driver, taking into account driver acoustic delays, magnitude and phase information.
How We Voiced The Systems
This white paper is a brief description of how we reached our goal of the ultimate point source studio monitor and how the systems were voiced. Each driver was measured in lots to find their characteristics and behavior attributes, this is an important step in determining how the drivers will vary not only at first but after they are used and broken in. A similar analogy is a new pair of shoes. There comes a time when the shoes are broken in and are comfortable. Same type of situation occurs with loudspeaker components.
By designing in quality materials for the drivers, minimal variance between drivers in the critical piston band of operation was found. All drivers exhibit a breakup mode outside their piston band of operation. The piston band is defined as the stable controlled region of operation where response energy is not the result of resonances or break up phenomenon. By utilizing this data, each system was designed to have a smooth response curve compensating for the directivity of the horn energy. Horn systems focus their energy to a particular area depending on their coverage pattern. If the crossover is not properly designed to compensate for the focused horn energy, the result can be very aggressive sounding and extremely fatiguing to the listener. Once the crossover is properly designed, the resulting sound quality is well detailed and natural.
In order to achieve a smooth sounding system with controlled dynamics and still maintain the capability to play loud and clean at high levels. The DSP filters were configured to equalize anomalies by cutting away unwanted energy as a first pass and then filling in areas to achieve a very smooth frequency response. Alignment of the horn and woofer acoustic centers determined in part by their physical spacing dimensions and off-set was brought into alignment electronically via the DSP delay feature. Delay was added to the woofer so the horn and compression driver combination could align acoustically to achieve a detailed point source.
Over a period of several months, measurements were made and then quantified by actual listening sessions among several prominent and well known parties. This team consists of acoustical, electrical, software, mechanical, DSP engineering and manufacturing support personnel as well as renowned recording engineers.
Each Equator product is inspected to conform to the standards and guidelines established by the Equator marketing, engineering and quality control departments. Performance and sound quality conform to equator precise standards. The equator Q-Series line of high quality Studio Monitor loudspeakers exemplifiers high performance, innovative technical design and high quality construction techniques thereby establishing a new path of standards and sound quality for others to follow.