Why can’t I use single GEO S805 or T4805?
The narrow (5degree) vertical coverage patterns of these devices make them impractical to be used unless deployed in a vertical array.
What are the benefits of cardioid technology in line array systems?
How can 8" loudspeakers properly reproduce low frequencies?
Long ago, Ampeg sold a superb bass guitar rig called the PR-810H Dual Bass Cabinet. If you ever heard a PR-810H, you know cone area is more important than individual cone size in determining how efficiently LF is reproduced. Specifically, LF radiation efficiency is defined by membrane surface area and excursion. The 8” loudspeakers used in GEO systems display very high excursion. And, because most of GEO-T LF energy is forward-radiated, the LF radiated by GEO T provides a higher output than a comparable 2x 15” LF section could provide.
What GEO to CD ratio should be defined?
This depends on music program.
How should I amplify CD18’s?
Recommended amplifier format is 2x amplifiers rated 3000W / 2Ω per channel and 1 NX242, powering up to 4x CD18’s.
Each amplifier feeds up to 2x CD18 (1 channel for rear section, 1 channel for front section).
How should I amplify GEO T’s?
Recommended amplifier format is 5x amplifiers rated 3000W/2Ω per channel with one NX242.
First amplifier feeds up to 12x HF drivers (6x HF per channel in parallel)
Second and third amplifiers feed up to 6x front LF/MF drivers in bridge mono mode each
Fourth and fifth amplifiers feed up to 6x LF in bridge mono mode each.
This format has been widely adopted by GEO T users, facilitating exchange between owners.
How should I amplify GEO S and CD12?
Recommended amplifier rack format is 2x amplifiers rated 3000W/2Ω per channel with one NX242.
How consistent is the frequency response over the covered zone?
This is highly depending on cluster size. Provided quantities are set as above, frequency response will not drop too fast in relation to MF and HF over distance.
Why are GEOSoft predicted values often pessimistic compared to my eventually on-site measurements?
GEOSoft pressure values are given for one cluster, free-field. Considering hard floor reflections, these values can increase by 3dB. With left and right clusters overlapping, another 3dB can be gained. Therefore, GEOSoft values can easily be under-estimate performance by up to 6dB.
How predictable is GEOSoft?
GEOSoft simulates GEO clusters through complex algorithms, involving Rayleigh Integral, sample summation and comprehensive field measurements. The simulated direct field is totally reliable in where compared against the final result.
How consistent is SPL over the covered zone?
Provided cluster curvature is properly defined, dBA level can fit within ±2dB over the entire audience.
How many GEO cabinets do I need to cover up to 80+m(260+yds)?
This depends on the LF requirements of the musical program. A good average value for proper LF control is obtained by dividing the audience depth in 2.5m(8.2ft) slices.
For GEO S, in a:
For GEO T, these quantities can be decreased because of the LF section's cardiod pattern, and slices can average 4m(13.1ft):
If these quantities are under-dimensioned, LF will decrease too quickly in relation to MF and HF over distance
How many GEO cabinets do I need for a 6000 people room?
The essential criteria to define quantity and cabinet type is not room capacity, but music program and SPL needs. Also remember that the taller the cluster, the better is LF control.
Provided that the room is not larger than deep for: