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CX335 User Manual v1.0

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‘peak’) indicators on the system’s power amplifiers. PEAK 
should be set so that the amplifiers do not clip at even the 
highest signal levels. The idea is that the CX335’s peak limiter 
should be active, not the clip protection in the amplifier. The 
red LIMIT LED adjacent to the PEAK control shows when 
the peak limiter is applying limiting. However, if it illuminates 
more than occasionally, the CX335 is not adjusted for 
optimum performance and the compressor controls should 
be readjusted to give more gain reduction.

Mode 2 – Soft Knee/Slow Envelope:
This compressor mode will still yield musical results, but will 
tend to allow very fast transients through the compressor 
section. Therefore, for continued amplifier and loudspeaker 
protection, more peak limiting will be required, and you 
should be sure that there is sufficient overhead in terms of 
speaker power handling.

KNEE

THRESHOLD

RATIO

PEAK

GAIN

BYPASS

4

4

0

3

10

- +

8

8

NORMAL

BYPASS

12

12

dB

LIMIT

dBu

6

15

20

0

26

-

NORMAL

SOFT

SLOW

HARD

3

-2

-4

6

2

5

10

20

1.5

1.2

:1

-10

-15

-20

+10

5

0

dBu

ENVELOPE

Setting up the CX335 in Mode 2 is exactly the same 
procedure as for Mode 1 (above). The main difference in 
operation is that some signal peaks may have the potential 
for causing problems further along the signal chain; note 
the remark above regarding the necessity for ample system 
headroom.

Mode 3 – Hard Knee/Normal Envelope:
Hard knee operation, though more “precise”, is generally 
slightly more noticeable in terms of audible artefacts 
(especially at high settings of RATIO).
For compression only, set THRESHOLD to between 0 and 
8 dB below the maximum input signal level and RATIO 
to about 5:1 or slightly higher. (Note that the higher the 
ratio, the more audible the effects of compression.) For 
compression and limiting, set RATIO to 20:1 or higher.  With 
programme at the normal level, adjust GAIN while pressing 

BYPASS several times, until the output meters indicate 
roughly the same level when the compressor is bypassed as 
when it is in circuit.

KNEE

THRESHOLD

RATIO

PEAK

GAIN

BYPASS

4

4

0

3

10

- +

8

8

NORMAL

BYPASS

12

12

dB

LIMIT

dBu

6

15

20

0

26

-

NORMAL

SOFT

SLOW

HARD

3

-2

-4

6

2

5

10

20

1.5

1.2

:1

-10

-15

-20

+10

5

0

dBu

ENVELOPE

In this mode, quieter signals pass through the compressor 
unprocessed, but louder signals (i.e., those above the 
threshold) will be compressed (activity of the gain reduction 
meter will confirm this). Adjust the PEAK control as 
described for Mode 1 (above). The LIMIT LED is likely to 
flicker more often than in Mode 1, especially with very 
percussive tracks at high level.  No artefacts should be 

noticeable until very high input levels are used; under these 
conditions the CX335 will take control to preserve system 
integrity.
NOTE: See also “Intelligent Limiting” below

Mode 4 – Hard Knee/Slow Envelope:
This mode is likely to be the most noticeable (especially with 
high settings of RATIO and/or fast dance tracks).
For compression only, set THRESHOLD to between 0 and 
8 dB below the maximum input signal level and RATIO 
to about 5:1 or slightly higher. (Note that the higher the 
ratio, the more audible the effects of compression.) For 
compression and limiting, set RATIO to 20:1 or higher. A 
high ratio setting will allow the THRESHOLD setting to 
accurately establish the maximum output level. As the ratio 
is decreased, the threshold setting should also be reduced 
to compensate. With programme at the normal level, 
adjust GAIN while pressing BYPASS several times, until the 
output meters indicate roughly the same level when the 
compressor is bypassed as when it is in circuit. Adjust the 
PEAK control as described for Mode 1 (above).

KNEE

THRESHOLD

RATIO

PEAK

GAIN

BYPASS

4

4

0

3

10

- +

8

8

NORMAL

BYPASS

12

12

dB

LIMIT

dBu

6

15

20

0

26

-

NORMAL

SOFT

SLOW

HARD

3

-2

-4

6

2

5

10

20

1.5

1.2

:1

-10

-15

-20

+10

5

0

dBu

ENVELOPE

In this mode, quieter signals pass through the compressor 
unprocessed, but louder input signals (i.e., those above the 
threshold) will be compressed. However, note that the initial 
peaks of transient signals are likely to be passed through the 
compressor unprocessed.

Intelligent Limiting

As the compressor section of the CX335 has a maximum 
ratio setting of ∞ to 1, it may be used to provide limiting 
rather just compression. Because the compressor makes 
programme-dependant adjustments to the attack and release 
times, and the split-frequency side chain detects signal levels 

in both channels, the limiting action produced is largely 
automatic.
Set the CX335 to Mode 3 (Hard Knee/Normal Envelope), as 
described above. Set the THRESHOLD control to the level 
at which limiting is to be applied. Set the RATIO control to 
maximum (infinity).  Set the GAIN control as for the other 
Modes: with programme at the normal level, adjust GAIN 
while pressing BYPASS several times, until the output meters 
indicate roughly the same level when the compressor is 
bypassed as when it is in circuit.

KNEE

THRESHOLD

RATIO

PEAK

GAIN

BYPASS

4

4

0

3

10

- +

8

8

NORMAL

BYPASS

12

12

dB

LIMIT

dBu

6

15

20

0

26

-

NORMAL

SOFT

SLOW

HARD

3

-2

-4

6

2

5

10

20

1.5

1.2

:1

-10

-15

-20

+10

5

0

dBu

ENVELOPE

Summary of Contents for CX335

Page 1: ...ssor Limiter CX 335 Power GAIN REDUCTION OUTPUT DISPLAY 30 20 20 16 15 12 10 8 6 4 4 0dB 2 4 1 8 0dB 12 KNEE THRESHOLD RATIO PEAK GAIN BYPASS 4 4 0 3 10 8 8 NORMAL BYPASS 12 12 dB L R LIMIT dBu 6 15 2...

Page 2: ...feat the safety purpose of the polarized or grounding type plug A polarized plug has two blades with one wider than the other A grounding type plug has two blades and a third grounding prong The wide...

Page 3: ...Box 5 Block Diagram 6 Front panel descriptions 6 Rear panel descriptions 7 Installation 8 Mechanical 8 Connections and adjustments 8 Chassis Ground Terminal 10 Fitting the tamper proof cover 10 Operat...

Page 4: ...mains transformer has a primary winding with both 230V and 115V tappings enabling the unit to be operated from mains voltages in the ranges 220V to 240V or 110V to 120V The voltage range to which the...

Page 5: ...of up to 26 dBu The CX335 is extremely transparent in operation and when set correctly imposes minimum colouration on the audio programme CX335 main features Stereo compressor limiter for dynamic ran...

Page 6: ...MIT red LED illuminates when the peak limiter is active 6 GAIN adjust to match the output level to the input level on normal programme material when the CX335 is active 7 ENVELOPE push button switch O...

Page 7: ...and right channels 14 OUTPUTS 2 x XLR3M connectors electronically balanced outputs for left and right channels 15 EXTERNALVCA INTERFACE 9 pin female Dsub connector for external DC control ofVCA this c...

Page 8: ...ory setting is printed on the rear panel below the IEC connector If it is necessary to change the mains voltage setting please refer to the Appendix of this User Guide Changing the AC Voltage setting...

Page 9: ...remote relay as shown 1 9 8 7 6 5 4 3 2 N O RELAY CONTACTS Note that to achieve maximum attenuation the relay contacts should be wired directly to pins 3 and 5 of the Dsub connecter In this case the m...

Page 10: ...o compression is applied However above the threshold the transfer characteristic is closer to the horizontal so the corresponding output signal level in this case is only 22 5 dB This is because the 1...

Page 11: ...the peak limiter operates only rarely if at all if it is to be used purely for peak protection Adjustments Finding the optimum settings for the front panel controls is relatively straightforward Howe...

Page 12: ...scribed for Mode 1 above The LIMIT LED is likely to flicker more often than in Mode 1 especially with very percussive tracks at high level No artefacts should be noticeable until very high input level...

Page 13: ...pped holes in the front panel and tighten with a nut driver 5 Fit the security cover over the brackets and secure it in place with the two M3 x 6 hex head screws supplied The four small holes in the u...

Page 14: ...ons The CX335 Compressor Limiter fully conforms to the relevant electromagnetic compatibility EMC standards and is technically well behaved You should experience no problems interfacing it to other it...

Page 15: ...cally balanced XLR3M Output Impedance 80 ohms Max Output Level 26 dBu Minimum Output Load 600 ohms Compressor Threshold range 20 to 10 dBu Ratio Adjustable unity no compression to brick wall limiting...

Page 16: ...Cloud Electronics Limited 140 Staniforth Road Sheffield S9 3HF England Tel 44 0 114 244 7051 Fax 44 0 114 242 5462 email info cloud co uk web www cloud co uk...

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