This white paper details how we reached our goal of manufacturing our Zero-Point Reference Q Series Studio Monitors. Each Equator product is expected to conform to the standards and guidelines established by the Equator marketing, engineering and quality control departments. Performance and sound quality conform to precise standards. The equator Q Series line of high quality Studio Monitors exemplify high performance, innovative technical design and high quality construction techniques thereby establishing a new path of standards and sound quality for others to follow.
Navigate the white paper by selecting a category above.
Advantages of a Coaxial Studio Monitor
The directional and power response characteristics related to how a studio monitor distributes sound into the room are determined by the driver placement on the front baffle of the speaker cabinet. If the drivers are aligned vertically on the speaker baffle, such as in a two-way loudspeaker system with the woofer below or in some cases above the tweeter, the horizontal frequency response coverage pattern will generally be smooth. However measuring up and down along the vertical plane, the vertical frequency response coverage patterns will exhibit cancellations above and below the on-axis location. These cancellations occur mainly throughout the crossover frequency range resulting in an uneven vertical coverage pattern. The more drivers that are used such as in a 3-way or 4-way systems, further complicate this situation.
Speaker crossovers are designed with the measurement microphone on axis with the loudspeaker, usually positioned on the HF driver or between the HF and LF drivers. As the microphone is moved above and below the on-axis location, the distances from each driver to the microphone location become different. Since the drivers are producing some of the same frequency information, the energy from the drivers will cancel each other as it arrives at the microphone. This occurs because the energy arrives at different times from the drivers to the microphone and not in phase with each other. This cancellation is known as lobbing. The effects of lobbing occur predominately when two drivers are reproducing the same frequencies but the energy from these sources are not in sync. This same situation occurs when the loudspeaker is used in its application except the microphone is replaced by the listener's ears. The frequency response of two sound sources of a known distance apart can be calculated using the equation in Figure 1.
Formula for calculating the frequency response of two sound sources based on a particular frequency and known distance apart.
D = Distance Between Drivers
c = Speed of Sound
f = Frequency Measured
A= Angle of measurement from speaker axis.
In a typical two-way studio monitor, the woofer and tweeter drivers each produce primarily lows and highs respectively except in the crossover frequency range where there is significant overlap of the frequencies produced right in the critical 800Hz to 3KHz region, which dramatically affects how well vocals and other instruments are recreated and imaged in the space between and around your monitors. It is in this frequency range where the smooth off-axis benefits of a well designed coaxial driver loudspeaker and the lobbing off-axis disadvantages of a non-coaxial driver loudspeaker are most audible.
This illustrates frequency response cancellations of two driver sources. Their centers spaced ten inches apart. Notice how each produce the same frequencies at 500Hz, 1000Hz and 2000Hz. Generally a HF driver would not be expected to reproduce frequencies down to 500Hz unless of course it was a very large horn with a large format compression driver. Therefore 500 Hz is shown only to illustrate that cancellation at 500 Hz or lower frequencies are generally not an issue with typical 10-inch spacing between two drivers.
Graphic plots of calculations for off-axis frequency response measurements through the crossover range frequencies for a typical two-way loudspeaker system. LF and HF drivers mounted on baffle and their centers spaced 10 inches apart.
Between 1000Hz and 2000Hz is the frequency range that is usually associated with crossover frequencies where both the upper-end of the LF driver and lower-end of the HF drivers overlap and sum to produce midrange frequencies. Illustrated in figure 3 is the frequency response at various angles when the distance between two sound sources is zero, such as in a well designed coaxial loudspeaker system. The off-axis frequency response is smooth, without any aberrations or lobbing anomalies. This results in a seamless sound quality unobtainable in non-coaxial loudspeaker designs.
Graphic plots of calculations for off-axis frequency response measurements through the crossover range frequencies in a typical two-way coaxial loudspeaker system with the LF and HF drivers arranged in a coaxial alignment sharing the same axis on baffle.
This illustrates frequency response cancellations of two driver sources. Their centers spaced ten inches apart. Notice how each produce the same frequencies at 500Hz, 1000Hz and 2000Hz. Generally a HF driver would not be expected to reproduce frequencies down to 500Hz unless of course it was a very large horn with a large format compression driver. Therefore 500 Hz is shown only to illustrate that cancellation at 500 Hz or lower frequencies are generally not an issue with typical 10-inch spacing between two drivers. 
Graphic plots of calculations for off-axis frequency response measurements through the crossover range frequencies in a typical two-way coaxial loudspeaker system with the LF and HF drivers arranged in a coaxial alignment sharing the same axis on baffle.