Nexo RS - Manual (Page 41)

RAY SUB S IMPLEMENTATION Page 41/54
NEXO recommends that main system and subwoofer systems are adjusted so that arrivals from RS18
and Main System are coincident at a fairly distant listening position (mixing position or further).
Because of proper acoustic reference point definition in NEXO TDControllers DSP setups, this method
is highly reliable.
7.4.4 Alignment with phase measurement
Phase measurement with real time FFT analyzer can also provide reliable measurements, provided:
• measurement microphone is set on the ground to avoid floor interference in the reading;
• floor is perfectly rigid (concrete);
• measurement microphone is set far from any walls / ceiling, or inside angles / corners;
• coherence values are high (typically above 75%).
If one of above conditions is not respected, then distance measurement should be preferred.
7.5 Recommended installation tools and equipment
• Tape measure – should be 30m/100ft in length and be of durable fibre material. Have one per array
available to speed up the installation process.
• Laser Inclinometer – For measuring vertical and horizontal angles in the venue. An ideal product is
the Calpac ‘Laser projecting a dot’ version which costs approximately 60 €.
• Spirit level – used to ascertain the trueness of the surface from which the angle measurements
originate.
• Rangefinder measuring device – either a Disto type laser measure or an optical laser rangefinder can
be used. Devices such as the Bushnell ‘Yardage Pro’ sports rangefinders provide sufficiently
accuracy and are easy to use. They have the additional advantage of working very well in bright
sunlight.
• Electronic calculator with trigonometric functions to calculate the height from ground level to points in
the room. The formula to calculate height of a point from measured angle and distance is:
• Height of point = Sin(vertical angle in degrees) x distance to point
• NB: Take care when using spreadsheets as they calculate using radians by default. To convert
degrees to radians use the formula:
• Angle (in radians)=3.142 x Angle (in degrees)/180
• Computer – Laptop or Desktop PC running Windows 2000 or XP with the current version of NEXO
GeoSoft2 installed. It is not possible to configure a Geo tangent array properly without using
GeoSoft2. Note that, when GeoSoft2 designs are prepared prior to arrival at the venue, it is often
r
1
r
2
Mixing position
or further