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special reprint 

12/09_01/10 

production partner 

1

T

he  CXM 15 from Dynacord, a manufacturer

based in Straubing (Germany), is a 15"/1.4" box

with a wedge design. The cabinet has been

kept especially flat and compact so as to be as

unobtrusive and easy to position as possible

on stage. Despite the advent of in-ear monito-

ring, floor monitors are no relic of the past.

On grounds of cost alone and the relatively

time-consuming handling, in-ear monitoring

is often not possible, and a great many per-

formers and technicians in any case prefer

classical monitoring on stage – and for a wide

variety of reasons. The demands placed on

the loudspeakers used on stage are very high:

"unobtrusiveness" is of particular importance

if the set is to remain uncluttered and the

lines of sight of audience members (and

cameras) unobstructed.

From an acoustic standpoint, a consistent

directionality and a frequency response

free from narrow-band ridges are what is

required, the aim in each case being to

reduce susceptibility to feedback, as – along

with the polar pattern of the microphones

– the performance of the monitors plays a

leading role here. Depending upon the

application, further factors, such as the ade-

Dynacord CXM15

Coaxial floor monitor with optional FIR processing

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www.promedianews.de

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Summary of Contents for CXM15

Page 1: ...ons The demands placed on the loudspeakers used on stage are very high unobtrusiveness is of particular importance if the set is to remain uncluttered and the lines of sight of audience members and cameras unobstructed From an acoustic standpoint a consistent directionality and a frequency response free from narrow band ridges are what is required the aim in each case being to reduce susceptibilit...

Page 2: ... front grille with its foam backing The way the front grille is attached here with very solid threaded screws represents a great improvement over the screw or clamp designs you usually find You can remove and replace the grille umpteen times here with no problems whatsoever Depending upon the type of show monitors on stage can be exposed to a considerable amount of dirt so it is important to be ab...

Page 3: ... supervision IRIS Net offers a series of useful functions both for the power amplifiers and the connected loud speakers In addition to pilot tone supervi sion these allow the load impedance of the network and the prevailing thermal condi tions to be checked Another very impor tant function is measurement of the impe The RCM 26 IRIS Net module dance of the connected loudspeakers Here instead of a s...

Page 4: ...et the nominal coverage angle of the CXM 15 is given as 60 which due to the coaxial design and circular horn is valid for all planes Any discrepancies could only be attributable to the enclosure and edge effects produced by it Figures 6 and 7 show the isobar curves for the hori zontal narrow side and vertical wide side planes The nominal value of 60 as a mean value above 1 kHz is arrived at by a s...

Page 5: ...2 Phase response of the CXM 15 in passive mode Fig 3 Frequency response and sensitivity of the CXM 15 in floor monitor position Fig 4 Impedance curve of the CXM 15 in passive mode showing the minimum impedance of 6 8 ohms at 217 Hz and the tuning frequen cy of the bass reflect resonator at 70 Hz Fig 5 The spectrogram of the CXM 15 in passive mode reveals a fairly pronounced resonance just below 1 ...

Page 6: ...nction its latency can be just as long or short as that of an IIR filter The latency is only a by product of the line ar phase approach What is needed therefo re is to find a good compromise with a suf ficiently short linear phase FIR filter combi ned with an IIR filter The IIR filter is then used where the short FIR filter for want of frequency selectivity can no longer interve ne i e at the bott...

Page 7: ...ce supervision with the measured curve shown against the background of the reference range Fig 15 Overview window in the IRIS Net software showing the H5000 power amplifier left and a flow diagram of the routing and signal processing performed by the dual channel RCM 26 module Fig 16 FIR filter functions thin lines and the frequency response of the loudspeakers together with the filters The phase ...

Page 8: ...at arises next is which of the four controller modes to choo se Whether the monitor is driven in two way active mode or passive is likely to be determined by economic considerations or the guidelines of the customer so the choi ce boils down to that between FIR and IIR filters Figures 10 and 11 show the amplitu de and phase response of the CXM 15 in passive mode without the controller in green as ...

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