Manual Model 2049 Stereo Compressor
Kultube (Model 2049) Manual Version 1.1 – 11/2004 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 Introduction .............................................................................................. Particular Feature, Equipment ................................................................... Hookup & Security Advices ........................................................................ Power Supply ............................................................................................ 4 4 5 5 Connections Rear Panel/Wiring .....................................................
Introduction The Kultube is an extremely versatile compressor with a broad range of control facilities that cover all typical compressor applications. From improved stereo mixes in the “MIDI Studio“ to surround mastering with several devices connected, all jobs can be undertaken to the highest degree of sound quality. You can, for example, choose between the hard and soft-knee characteristic and insert external devices via a side-chain input for external control.
Hookup & Security Advices Carefully select a place for setting up the Kultube. The unit should be situated away from heat sources and direct sunlight. Avoid installation in environments exposed to vibrations, dust, heat, cold or moisture. Keep the unit away from transformers or motors or any other unit that could generate large variations in power supply or cause electrical interferences. Do not install the unit in proximity to power amplifiers or digital processors.
2 3 1 6 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-proof and protects against HF-interference, placement of the unit is very important since it amplifies microphone signals as well as other unwanted signals. Before connecting the Kultube or any other equipment turn off all power. Adjust the voltage setting on the back so that it corresponds with the power conditions.
Connections Sockets & Rear Switch Sidechain inputs This jack is used as a sidechain 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 RCA 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 RCA plug (connected to the Kultube) and two mono RCA 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 CCW provides no control, and fully CW provides compression starting at a level of approx. –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, ti.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.
Operating 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.
Operating 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.
Operating 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.
Operating 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.
Operating 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).
Operating 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.
Operating 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) .......... 10 Hz-150 kHz Common mode rejection (@ 0 dBu) ......... 1 kHz: › 80 dB / 10 kHz: › 65 dB THD & N (@ 0 dBu) .................................. › 82 dB S/N (A-weighted) .................................... 90 dBu Inputs Input impedance ..................................... Line: 20 kOhm Max. input level ...................................... Line: +22 dBu Outputs Max. output level (XLR & Jack) ................
Warranty SPL electronics GmbH (hereafter called SPL) products are warranted only in the country where purchased, through the authorized SPL distributor in that country, against defects in material or workmanship. The specific period of this limited warranty shall be that which is described to the original retail purchaser by the authorized SPL dealer or distributor at the time of purchase.
Kultube – Manual Your notes .................................................................................. .................................................................................. .................................................................................. .................................................................................. .................................................................................. ....................................................................
