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4.2.2 Ratio control

This control sets the change of input level to output level but only for the signals that exceed the threshold. The scale 
of the ratio control on the front panel (calibrated in dB) indicates how much input level is required to increase the 
output level by 1 dB. If you have a ratio equal to 1:1 you will get the same level of input and output signal: So, no level 
change.

If you have a ratio of 2:1 this means that for every 2dB increase of the input level (above threshold) you will get an 
increase of output level of 1 dB. ON the same way, a ratio of 10:1 means that for every 10 dB increase of the input 
level (above threshold) you will get an increase in output level equal to 1dB, and so on.

You need to be aware that higher ratio settings produce less natural sounds so if you wish a more minute effect on 
the dynamic range of a program you should use a Ratio of 4:1 or lower.

With the SKC circuit (Smart Knee Control) you can avoid aggressive compression generated by using high ratios. 
How we achieve this? Introducing a "soft knee" curve in the range of up to 10dB above the threshold level. Hard Knee 
compression is then used beyond this range.

4.2.3 Attack control

The attack time represents the amount of time that passes before the compressor start to lower the output 
level when the signal is above the threshold point.

For very fast transients such as drums, handclaps, etc, a short attack time will be used. These peaks are
consequently carefully regulated by the compressor. Sounds of other nature will get advantages if longer
attack times are used. Anyway, our advice is always to begin the process with longer attack times. Then 
you can start gradually to reduce the attack time. IN the BK 2.0 the attack time can be set in a range of 
1 to 200 milliseconds.

Output 

Hard Knee 

Threshold

Gain 0 dB

Ratio 2:1

Ratio 4:1

Limiter :1

SKC Curve

Input

Chart.5: SKC characteristic of the compressor section

4.2.4 Release control

This control determines how much time the compressor needs to get back to normal gain when the audio signal 
falls below the set threshold.

A too short release time will make the volume to fluctuate and you will experience pumping effect. A too long release 
time will give you pumping and breathing effect especially when you have loud passage followed by a quite passage. 
The release time on BK 2.0 can be set from 0.05 to 4 seconds.

4.2.5 Auto switch

This switch turns off the possibility of manually set the attack and release times. An intelligent program recognition 
circuit will automatically set the attack and release times. In such way, undesirable effects such as distortion and 
pumping will be avoided.

4.2.6 Output control

This Control is indispensable to compensate the loss of level at output level generated by the gain reduction caused 
by the compression and limiting processing

4.2.7 Effect switch

This switch simply turns off the correspondent channel. This is useful to compare quickly the processed and 
unprocessed signal.

Summary of Contents for BK 2.0

Page 1: ...BK 2 0 User s Manual LTO R R www altoproaudio com Version 2 0 Dec 2002 English English COMPRESSOR LIMITER GATE ...

Page 2: ... apparatus and dis connect the power source Operating Conditions This apparatus shall not be exposed to dripping or spl ashing and that no objects filled with liquids such as vases shall be placed on this apparatus To reduce the risk of fire or electric shock do not expose this apparatus to rain or moisture Do not use this apparatus near water Install in accordance with the manufacturer s instruct...

Page 3: ...will create the new ones From our side we guarantee you and we will guarantee you also in future the best quality the best fruits of our continuous researches and the best prices Thank you very much LTO AUDIO TEAM Thanks for choosing LTO BK 2 0 Compressor Limter Gate and thanks for choosing one of the results of LTOAUDIO TEAM job and researches Our LTO BK 2 0 is the result of many hours of listeni...

Page 4: ...S 6 3 1 Expander Gate Section 3 2 Compressor Section 3 3 Dynamic Enhancer Section 3 4 The Rear Panel 4 READY TO ROLL 9 4 1 Expander Gate Section 4 2 Compressor Section 4 3 Limiter Section 6 TECHNICAL SPECIFICATIONS 13 7 BLOCK DIAGRAM 14 5 INSTALLATION AND CONNECTION 11 5 1 Mains Connection 5 2 Audio Connection 5 3 Rack Mounting 8 WARRANTY 15 ...

Page 5: ...k limiter SGC This function includes two important functions Clipper and program limiter The peak limiter will be activated above a certain threshold that is adjusted by the User and will radically restrict signal peaks But what about if the threshold of the Limiter is surpassed only for a few milliseconds SGC will turn on automatically and reduce the output signal so that you will not hear any di...

Page 6: ...se the volume during low passages and decrease the volume during loud passages Unfortunately even the Great Houdini would not be fast enough to monitor carefully the speed of the musical signal and it would be impossible to detect signal peaks and consequently levelling them out Manual control is therefore out of question The answer is AGC automatic gain control a device that will monitor the sign...

Page 7: ......

Page 8: ......

Page 9: ...ed when compression is taking place 3 4 The Back Panel Pic 5 The Back Panel Layout Of The BK 2 0 13 12 15 14 16 OUTPUT INPUT TIP INPUT RING OUTPUT SLEEVE GROUND OUTPUT INPUT TIP INPUT RING OUTPUT SLEEVE GROUND CHANNEL 1 SIDECHAIN CHANNEL 2 SIDECHAIN AC INPUT 95 120V 210 240V6 0 50Hz Rated Power Consumption 8W FUSE 210 240V T100mAL 250VAC 95 120V 200mA 250VAC REPLACE FUSE WITH CORRECT TYPE ONLY SER...

Page 10: ...processor It simply cut off the entire signal below a certain set threshold The BK 2 0 is equipped with a new kind of expander the SRC Smart Ratio Control The ratio of the SRC is automatically adjusted according to the audio signal level In fact conventional expanders could easily cut part of the musical program with unacceptable result The gain changes become audible We have equipped the SRC with...

Page 11: ...aps etc a short attack time will be used These peaks are consequently carefully regulated by the compressor Sounds of other nature will get advantages if longer attack times are used Anyway our advice is always to begin the process with longer attack times Then you can start gradually to reduce the attack time IN the BK 2 0 the attack time can be set in a range of 1 to 200 milliseconds Output Hard...

Page 12: ... IN this way you will avoid undesired dynamic distortion But what about if you are mixing a program with a wide range of frequencies In this case you should choose a setting that would benefit the low frequency better Well life is not that easy for conventional compressor limiters Ok you handle an audio signal made by a wide range of frequencies and you have chosen a longer attack time But if are ...

Page 13: ...nput b In Line Connection Please see following drawing for details TIP RING SLEEVE TIP RING SLEEVE TIP RING SLEEVE TIP SLEEVE TIP SLEEVE TIP RING SLEEVE TIP SLEEVE TIP RING SLEEVE SLEEVE RING TIP SLEEVE RING TIP SLEEVE TIP Tip Ring Sleeve Tip Ring Sleeve Tip Ring Sleeve Tip Ring Sleeve Tip Sleeve Tip Sleeve Tip Sleeve Tip Ring Sleeve 1 2 3 1 2 3 1 2 3 Tip Ring Sleeve 1 2 3 Centre Centre Centre Scr...

Page 14: ......

Page 15: ...0 05ms to 4s 20dB From 20 to 20dB Interactive Expander Gate Variable from OFF to 15dB Dynamically controlled frequency correction Variable from off to 6 Bypass switch Programme dependent attack and release time Type Impedance Maximum input level Type Impedance Maximum output level Frequency response THD N 1kHz 4dBu IMD SMPTE 10dBu Noise Hum unity gain Noise Hum fully off Cross talk 20kHz CMR 1kHz ...

Page 16: ...15 7 BLOCK DIAGRAM Chart 8 Block diagram of the BK 2 0 ...

Page 17: ...TO of 1 year from the purchase date if you have completed the Warranty Registration Card in time 3 3 During the warranty service may repair or replace this product at its own option at no charge to you for LTO parts or for labor in accordance with the right side of this limited warranty 3 4 This warranty does not apply to the damages to this product that occurred as the following conditions Normal...

Page 18: ...audio com Tel 886 4 22313737 email alto altoproaudio com Fax 886 4 22346757 All rights reserved to ALTO All features and content might be changed without prior notice Any photocopy translation or reproduction of part of this manual without written permission is forbidden Copyright 2003 Sekaku Electron ...

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