Manual Model 2049 Stereo Compressor
Kultube (Model 2049) Manual Version 1.2 – 11/2008 R & D: Ruben Tilgner The information in this document has been carefully verified and is assumed to be correct. However Sound Performance Lab (SPL) reserves the right to modify the product described in this manual at any time. Changes without notice. This document is the property of SPL and may not be copied or reproduced in any manner, in part or full without the authorization of SPL.
Content Important Security Information ................................................................. 4 Installation, Power Supply ........................................................................ 6 Introduction .............................................................................................. 7 Connections Rear Panel/Wiring ..................................................................................... 8 General Advices, Sockets & Switches .......................................
Important Security Information Please note and retain this manual. Carefully read and follow all of the safety and operating instructions before you use the machine. Be doubly careful to follow all warnings and special safety instructions noted in this manual and on the unit. Connections: Only use the connections as described. Other connections can lead to health risks and equipment damage.
Important Security Information Air Circulation: Chassis openings offer ventilation and serve to protect the machine from overheating. NEVER cover or otherwise close off these openings. NEVER place the machine on a soft surface (carpet, sofa, etc.). Make sure to provide for a mounting space of 4-5 cm/2 inches when mounting the machine in racks or cabinets. Controls And Switches: Operate the controls and switches only as described in the manual.
Installation Be very careful to check that the rear chassis power selection switch is set to the correct local line voltage position before using the unit (230 V position: 220-240 V/50 Hz, 115 V position: 110-120 V/60 Hz)! When in doubt about a source, contact your dealer or a professional electrician. Before connecting any equipment make sure that any machine to be connected is turned off. Follow all safety instructions from page 5. Place the unit on a level and stable surface.
Introduction The Kultube user disposes over a unique range of powerful compression tools ranging from subtle unobtrusive processing to very obvious ‘effect‘ compressions. Used conventionally or as an effect, in professional recording or mastering applications, the Kultube combines outstanding audio quality with the acclaimed musicality and user-friendliness that SPL units stand for.
2 3 1 8 1=GND 2=Hot (+) 3=Cold (-) Pin wiring XLR Input: 1 3 2 Further Kultubes as slaves in multichannel link mode 1 = GND 2 = Hot (+) 3 = Cold (-) Pin wiring XLR Output: Connector for external processing units (e. g.
Connections General Advices Again, while Kultube‘s housing is EMV safe and protects against HF interferences, proper placement of the unit is very important. Before connecting the Kultube or any other equipment turn off all power. Adjust the voltage setting on the back so that it corresponds with your local electrical power conditions.
Connections Sockets & Rear Switch Side-chain inputs This jack is used as a side-chain input for connecting an external audio signal to control the Kultube (e. g. an equalizer for frequency dependent processing). It is configured as a stereo TRS jack, with the left channel on the tip and the right channel on the ring. Ideally you should use a normal insert cable that combines a stereo TRS plug (connected to the Kultube) and two mono TRS plugs (connected to the control device).
Switches Control Elements Please note also the information on various controls under „Understanding and enjoying the Kultube“ starting page 12. RED/VU This switch changes the VU meter over to Gain Reduction mode. The indicator needle then jumps to the 0 dB value and moves to the left with increasing compression. The scaled values now refer to gain reduction. If the RED/VU switch is not pressed, the VU meter indicates the output level.
Control Elements Switches Progressive Time Control: ATTACK This function allows to switch in an adjustable automatization of the time constants which is set up with the ATTACK control. Put simply you can now influence the compression intensity for rapid signal increases, or when the function is turned off determine the time until a certain compression level is reached.
Controls Control Elements THRESHOLD The Threshold control determines the compressor threshold value. The value scale for the THRESHOLD control indicates the level in dBu. Turning fully left provides no control, and fully right provides compression starting at a level of approximately –40 dBu. RATIO The RATIO control is used to set the ratio between the original signal and the compressed signal. A ratio of 1:4 means that a level increase of 4 dB on the input results in an output change of 1 dB.
Control Elements Controls TUBE HARMONICS The TUBE HARMONICS control allows you to drive the tube output stage infinitely variable to desperation: the more the control is turned in, the further the tube gets into saturation and the more harmonics are produced. The output level of this stage is automatically adjusted, i.e. it keeps virtually the same level as the input signal. This allows you to to change the entire sonic behavior of the tubes with just one control.
Operation Understanding and enjoying the Kultube The Ratio control As indicated above, this determines the ratio between the in- and output level above the threshold setting. The preset value specifies how the input dynamics should behave with respect to the output: a ratio of 1 to 2 means that only half of the dynamic change will be present on the output. At 10 dB of dynamics there will only be 5 dB on the output, whereas using a ratio of 1:8 means 10dB becomes just 1.25 dB, etc.
Operation Understanding and enjoying the Kultube In the latter case the ratio changes depending on the in0ut signal. As the preset threshold value is approached the ratio is comparatively small (1:1.5) and doesn’t reach the preset maximum value until high input levels are present. The result is much less conspicuous compression, since the process does not kick in as suddenly as with hard-knee mode. On the other hand, hard-knee results in greater loudness and density of the program material.
Operation Understanding and enjoying the Kultube Processed in this way, drums get more self assertion and sound ‚faster’. The best setting is not always easy to find, since you usually need to find a compromise. Very fast settings run the risk of producing audible distortions – especially in the case of low frequencies, since the compressor now tries to control each waveform rise. The corresponding control signal assumes a “saw-tooth” form which distorts the audio signal.
Operation Understanding and enjoying the Kultube Fig. 5, „Attack PTC“ Fig. 5 shows the control behavior using a sinus burst as an example. In various settings it is clearly to see that the burst signal remains almost unchanged in its form; only the intensity changes. The PTC feature can provide outstanding results not only for percussive signals but also for many other musical signals (vocals, guitar, bass, horns, synthesizers, etc.
Operation Understanding and enjoying the Kultube The release parameter is also for the most part responsible for unobtrusive compression. This means it is hard to find the perfect setting as with the Attack control – particularly in the case of complex summed signals a fixed release time may hardly be usable. As with the attack times you must always find a compromise: for very fast and short signal peaks (e.g. drums and percussion) you will want to select short release times (100 ms).
Operation Understanding and enjoying the Kultube Fig. 7b A B C Fig. 7c A B C For settings with larger averages the change in the release time is easy to recognize. With very small values the control voltage for the Gain Cell “sticks” to the rectified signal and works almost like an envelope follower. Fig. 8 on the next page shows the various effects of different release time settings on a sinus burst, although the principle is not as easily seen here.
Operation Understanding and enjoying the Kultube Fig 8 „Release – PTC“ Applications Using and enjoying the Kultube Summed signal processing Console: Inserts Send/Return The main application area for the Kultube is in stereo summed signal compression together with an analog mixing console. Here the Kultube is looped into the insert paths („Insert Send/Return“). The insert paths are generally in front of the console master fader so that the compressor is driven independent of the master fader settings.
Applications Using and enjoying the Kultube Sidechain External compression control Use of the SIDECHAIN inputs expands the possibilities for controlling compression. A typical application is frequency-selective compression, whereby an external equalizer is used to raise the frequencies at which the compressor should respond or to filter out the frequency band you wish the compressor to ignore.
Applications Using and enjoying the Kultube Multi-channel and 5.1 surround applications The Kultube lets you use the MULTI CHANNEL LINK function to link any number of devices for multi-channel or surround applications. Simply define a master for controlling all the other units (slaves). Each slave must be defined as a slave using the SLAVE switch on the front panel.
Specifications Measurements Frequency range (100 kHz = -3 dB) .......... Common mode rejection (@ 0 dBu) ......... THD & N (@ 0 dBu) .................................. S/N (A-weighted) .................................... 10 Hz-150 kHz 1 kHz: › 80 dB / 10 kHz: › 65 dB › 82 dB 90 dBu Inputs Input impedance ..................................... Line: 20 kOhm Max. input level ...................................... Line: +22 dBu Outputs Max. output level (XLR & Jack) ................
