User manual BEHRINGER T1953

[. . . ] T1953 Users Manual Version 1. 2 December 2002 TUBE ULTRAGAIN ENGLISH TUBE ULTRAGAIN T1953 SAFETY INSTRUCTIONS CAUTION: To reduce the risk of electric shock, do not remove the cover (or back). No user serviceable parts inside; refer servicing to qualified personnel. WARNING: To reduce the risk of fire or electric shock, do not expose this appliance to rain or moisture. This symbol, wherever it appears, alerts you to the presence of uninsulated dangerous voltage inside the enclosurevoltage that may be sufficient to constitute a risk of shock. This symbol, wherever it appears, alerts you to important operating and maintenance instructions in the accompanying literature. [. . . ] But tracks that are already laid can benefit from processing by the TUBE ULTRAGAIN. Make sure that the unit is switched to line, and that the PHASE REVERSE and HIGH PASS switches are not engaged. You can insert the TUBE ULTRAGAIN in the channel or subgroup inserts of your console. The TUBE ULTRAGAIN can also easily be used on the entire mix, when inserted in the main mix bus or as a serial devices between the desk and for instance a DAT recorder the whole mix can benefit from the warm tube sound. 4. TECHNICAL BACKGROUND The steady development of modern sound reinforcement systems has made it possible to produce almost any level of loudness. Yet, the increase in loudness goes in line with a need for optimized audio quality. To fully understand how the BEHRINGER TUBE ULTRAGAIN works you will need to know the meaning of a decibel and how audio dynamics work. With the TUBE ULTRAGAIN, as with any other type dynamics processor the amount of boost/attenuation applied is expressed in decibels (dB). The abbreviation dB is not a unit (although often used as one), but describes a logarithmic proportion. The entire dynamic range of human hearing (from the threshold of audibility to a jet-airplane, see fig. 4. 1) starts with about 0. 00002 Pa (threshold of audibility) and goes up to 130 Pa (threshold of pain). This also means that 0 dB is not silence, minus infinity dB will mean absolute silence. TECHNICAL BACKGROUND TUBE ULTRAGAIN T1953 160 Jet Engine 140 Threshold Of Pain Sound-Pressure Level (dB SPL) 120 Power Drill 100 Machinery Hall "Loud" Office Normal Conversation Quiet Apartment Recording Studio 80 60 40 20 Falling Leaves 0 Threshold Of Audibility Fig. 4. 1: Dynamic range of human hearing The range of sound pressure levels or the dynamic range of human hearing encompasses a factor of 10, 000, 000. This enormous range of values is difficult to handle and additionally does not represent the subjective perception of sound, since human hearing tends to use a logarithmic curve. When an increase in loudness by the factor two is perceived as one step, four times the loudness level equals two steps. So, the decibel is a unit of measurement that describes a level in relation to a reference quantity. To make clear which reference quantity is meant, the abbreviation SPL (sound pressure level) is sometimes used together with dB. Starting with a value of 0 dB SPL (= 2*10-5 Pa) for the threshold of audibility, any dB values can be calculated by means of the following formula: / = 20 log S2 S1 L = e. g. a reference sound pressure of 0. 00002 Pa p2 = the sound pressure (in Pa) produced by the sound source to be calculated log = decimal logarithm. As can be seen, human hearing has a very wide dynamic range of about 130 dB, which surpasses the range of a DAT or CD player with an approximate range of 96 dB. From a physical point of view, a 3 dB boost corresponds to an increase in power by the factor 2. [. . . ] Warranty services will be furnished only if the product is accompanied by a copy of the original retail dealers invoice. Any product deemed eligible for repair or replacement by BEHRINGER under the terms of this warranty will be repaired or replaced within 30 days of receipt of the product at BEHRINGER. If the product needs to be modified or adapted in order to comply with applicable technical or safety standards on a national or local level, in any country which is not the country for which the product was originally developed and manufactured, this modification/adaptation shall not be considered a defect in materials or workmanship. The warranty does not cover any such modification/adaptation, irrespective of whether it was carried out properly or not. [. . . ]