Frequency domain analysis
Frequency response graphs
GLM users will be familiar with this graph. It's the same one that appears after calibration to show the measured frequency response of your system (red line), GLM's corrective filtering (blue line), and the resulting response after correction (green line). GLM aims to achieve a flat response, giving you the best possible foundation to work from.
No dips below 200 Hz.
A significant dip at 75 Hz, perhaps caused by a reflection from the back wall at a distance of approx. 1.14 m (quarter-wavelength-rule). A position closer to the wall could improve the response.
Low frequency extension
All Genelec monitors provide exceptional bass extension relative to their size, yet each monitor's low-frequency response is in some way affected by positioning and overall room acoustics. GRADE identifies the position on the spectrum at which low frequencies drop to half the average sound pressure measured in the system’s midrange. The location of this level reduction is called the -6 dB point, and knowing it allows you to compare the performance of the monitors and subwoofers in your room with references from our anechoic chamber. In turn, this helps you to tweak their positioning for optimal bass extension. Monitors can be placed for instance, closer to walls or corners to lower the system's – 6 dB point by summing up the low frequencies.
This system’s low frequency response is extended due to its close proximity to a wall.
Similarly, GRADE measures a – 6 dB cutoff point for the high-frequency response of subwoofers.
Peaks and notches
GRADE creates a peaks and notches graph to highlight the room influences that affect each individual monitor’s frequency response. This is measured before calibration and is subject to many factors such as room size, acoustic treatment and positioning relative to hard surfaces. This readout gives you a clear picture of how monitor placement can be optimised through re-positioning, room improvements or negative equalisation.
The marked notches are of particular interest. They may be caused by hard-surface reflections at a certain distance, leading to frequency cancellation. Placement should be optimised to avoid these negative effects.