A COMPRE SS OR H PH OMPRESS O C A R AL AL P
The information in this document is subject to change without notice and shall not be deemed as a warranty by the manufacturer. No warranties, express or implied, are made with regard to the quality, suitability or accuracy of this document. The manufacturer reserves the right to change the contents of this document and/or the associated products at any time without the provision of prior notice.
Dear friend of audio culture, First of all, we would like to thank you sincerely for choosing the alpha compressor as your new mastering tool. From now on, you not only have the maximum possible audio quality in dynamics processing at your disposal, but also a complete arsenal of flexible and effective tools which will shift the results of your work to a new level.
Mounting The best way to place the alpha compressor is to put it on top of a rack. In this position, ventilation will be optimal and the unit will not heat up too much. In case you mount it into a 19“ rack or vertically into a console, please leave a free space of about 2cm on top and bottom so that the air can circulate freely. Also make sure that the rack rails can really carry the heavy weight: the device weighs about 16kg that should be reinforced from the back in case of doubt.
BASICS 6 Basic Design. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 Stereo Compression . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 Auto Fast . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 Feed Forward . . . . . . . . . . . . . .
BASICS - Basic Design Never fear! With its many options and quite a lot of controllers the alpha compressor might look a little tricky at first sight. In practical experience, however, it is a clearly structured and easy to use tool. The control elements are divided into three layers, whereas the left and the right channel sides are completely identical.
In the middle of the unit, right below the Gain reduction meters, there are three buttons to set the distinct operating modes of the alpha compressor: Active If this button is pressed (LED glows), the incoming signals will be processed in the alpha compressor. Otherwise there will be a hard bypass, whereas the Gain reduction meters will still stay active.
Thresh Attack Release Feed Forward Ratio Auto Fast On Attack x10 Gain dB ms Auto Fast Ratio ms EQ Gain EQ Freq SC Gain SC Freq Hz Release Feed Forward Auto Fast EQ Gain EQ Freq Mix Thresh Soft Clip On On Mix Soft Clip Auto Fast 1:X SC Gain SC Freq x10 dB On Soft Clip Gain Gain Reduction Direct Compressed Transformer On MS Mode Active Channel Link Direct Compressed Transformer On Stereo Compression In order to get a first impression of the sonic quality and th
Auto Fast (Attack) The Auto Fast function causes an automatic shortening of the control time on fast and loud signal peaks. This effect is easy to comprehend when compressing a preferably dynamic drum loop, for example. Please set the following values as a starting position: • • • • Attack: Release: Ratio: Threshold: 50ms 300ms 1:1,8 Set to a position that results in approx. 3-4dB Gain reduction Because of the quite long Attack time the snare and bass drum will be processed very moderately.
Feed Forward This function makes it possible to switch the junction of the Sidechain alternatively behind (Feedback) or in front (Feed Forward) of the actual compressor section. This has an enormous effect on the character of the compressor. Again, our drum loop can be used for demonstration: While processing in Feedback mode will run very smooth and even, switching into Feed Forward mode will result in a clearly more aggressive and harder kind of compression.
Thresh Attack Release Feed Forward Ratio Auto Fast On Attack x10 Gain dB ms Auto Fast Ratio ms EQ Gain EQ Freq SC Gain SC Freq Hz Release Feed Forward Auto Fast EQ Gain EQ Freq Mix Thresh Soft Clip On On Mix Soft Clip Auto Fast 1:X SC Gain SC Freq x10 Gain dB On Soft Clip Gain Reduction Direct Compressed Transformer On MS Mode Active Channel Link Direct Compressed Transformer On MS Matrix One of the most powerful features of the alpha compressor is its switch
Thresh Attack Release Feed Forward Ratio Auto Fast Attack x10 Hz Gain ms Auto Fast Mix Soft Clip Auto Fast 1:X SC Gain SC Freq On On dB ms Ratio EQ Gain EQ Freq SC Gain SC Freq Mix Release Feed Forward Auto Fast EQ Gain EQ Freq On Thresh Soft Clip x10 dB On Soft Clip Gain Gain Reduction Direct Compressed Transformer On MS Mode Active Channel Link Direct Compressed Transformer On Sidechain Filter The Sidechain filter allows frequency-dependent shaping of the c
Thresh Attack Release Feed Forward Ratio Auto Fast On Attack x10 Gain dB ms Ratio ms Auto Fast EQ Gain EQ Freq SC Gain SC Freq Hz Release Feed Forward Auto Fast EQ Gain EQ Freq Mix Thresh Soft Clip On On x10 Mix Soft Clip Auto Fast 1:X SC Gain SC Freq dB On Soft Clip Gain Gain Reduction Direct Compressed Transformer On MS Mode Active Channel Link Direct Compressed Transformer On Audio Filter The Audio filter is placed behind the compressor, avoiding unwanted
Thresh Attack Release Feed Forward Ratio Auto Fast On Attack x10 Gain dB ms Auto Fast Ratio ms EQ Gain EQ Freq SC Gain SC Freq Hz Release Feed Forward Auto Fast EQ Gain EQ Freq Mix Thresh Soft Clip On On x10 Mix Soft Clip Auto Fast 1:X SC Gain SC Freq Gain dB On Soft Clip Gain Reduction Direct Compressed Transformer On MS Mode Active Channel Link Direct Compressed Transformer On Mix Controller The Mix controller makes it possible to cross-fade between the unp
Thresh Attack Release Feed Forward Ratio Auto Fast Attack x10 Hz Gain dB ms Ratio ms Auto Fast EQ Gain EQ Freq SC Gain SC Freq Mix Release Feed Forward Auto Fast EQ Gain EQ Freq On Thresh Soft Clip On On Mix Soft Clip Auto Fast 1:X SC Gain SC Freq x10 dB On Soft Clip Gain Gain Reduction Direct Compressed Transformer On MS Mode Active Channel Link Direct Compressed Transformer On Soft Clip Limiter The Soft Clipper was designed to limit short, loud transients,
dB dB Feed Forward Lo Hi Direct 10 % Com Hz 0,5 1,5 2,0 Gain 2k0 0 1k0 3,5 500 300 220 12 HP -12 24 21 19 25 -5 -2 Soft Clip dB Auto Fast 1,2 1,3 1,4 1,1 Ratio 16 dB 14 On 3,0 1,7 5,5 8,0 On Hz 5,0 6,0 2k0 11 9,5 8,5 4307,5 2,4 12 4,0 2,1 1,9 2,2 1,8 3k3 1:X 280 340 1,6 30 4,0 11 40 50 80 SC Gain SC Freq 1k5 1k1 800 570 1k8 Transformer 10 8,0 11 6,0 430 ms -0,3 -0,3 LP -1 60 300 14 3,0 18 20 MS Mode 16 2,0 1,5 1
dB dB Feed Forward Lo Hi % Com 2k0 0,5 1,5 2,0 Gain Compressed 100 Hz 0 1k0 3,5 500 dB 4,5 x10 12 24 21 19 Transformer 11 10 8,0 -12 25 -5 -2 Soft Clip dB Auto Fast 1,2 1,3 1,4 1,1 Ratio 16 dB 14 On 3,0 1,7 5,5 8,0 On Hz 5,0 6,0 2k0 11 9,5 8,5 4307,5 2,4 12 4,0 2,1 1,9 2,2 1,8 3k3 1:X 280 340 1,6 30 4,0 11 40 50 80 SC Gain SC Freq 1k8 1k5 1k1 800 570 HP 430 ms -0,3 -0,3 300 LP -1 60 6,0 -12 -5 -2 75 100 150 Rele
dB dB Feed Forward Lo Hi 2,7 Direct % 2k0 dB 4,5 x10 12 dB HP -12 24 21 19 25 -5 -2 Soft Clip Transformer 11 10 8,0 LP 6,0 Auto Fast 1,2 1,3 1,4 1,1 Ratio 16 dB 14 On 3,0 1,7 5,5 8,0 On Hz 5,0 6,0 2k0 11 9,5 8,5 4307,5 2,4 12 4,0 2,1 1,9 2,2 1,8 3k3 1:X 280 340 1,6 30 4,0 11 40 50 80 SC Gain SC Freq 1k8 1k5 1k1 800 570 14 3,0 18 20 MS Mode 16 2,0 1,5 1,0 Active Gain Reduction Soft Clip 18 1,5 16 2,0 14 3,0 Channel L
dB dB Feed Forward Lo Hi Direct 10 Dir % 2k0 0,5 1,5 2,0 Gain Compressed Hz 0 1k0 3,5 500 dB 4,5 x10 12 24 21 19 Transformer 11 10 8,0 -12 25 -5 -2 Soft Clip dB Auto Fast 1,2 1,3 1,4 1,1 Ratio 16 dB 14 On 3,0 1,7 5,5 8,0 On Hz 5,0 6,0 2k0 11 9,5 8,5 4307,5 2,4 12 4,0 2,1 1,9 2,2 1,8 3k3 1:X 280 340 1,6 30 4,0 11 40 50 80 SC Gain SC Freq 1k8 1k5 1k1 800 570 HP 430 ms -0,3 -0,3 300 LP -1 60 6,0 -12 -5 -2 75 100 15
dB dB Feed Forward Lo Hi Direct % Com 2k0 0,5 1,5 2,0 Gain Compressed 100 Hz 0 1k0 3,5 500 dB 4,5 x10 12 24 21 19 Transformer 11 10 8,0 -12 25 -5 -2 Soft Clip dB Auto Fast 1,2 1,3 1,4 1,1 Ratio 16 dB 14 On 3,0 1,7 5,5 8,0 On Hz 5,0 6,0 2k0 11 9,5 8,5 4307,5 2,4 12 4,0 2,1 1,9 2,2 1,8 3k3 1:X 280 340 1,6 30 4,0 11 40 50 80 SC Gain SC Freq 1k8 1k5 1k1 800 570 HP 430 ms -0,3 -0,3 300 LP -1 60 6,0 -12 -5 -2 75 100 1
dB dB Feed Forward Lo Hi Direct 10 Dir % Com Hz 0,5 1,5 2,0 Gain 2k0 3,5 dB 4,5 x10 12 24 21 19 Transformer 11 10 8,0 -12 25 -5 -2 Soft Clip dB Auto Fast 1,2 1,3 1,4 1,1 Ratio 16 dB 14 On 3,0 1,7 5,5 8,0 On Hz 5,0 6,0 2k0 11 9,5 8,5 4307,5 2,4 12 4,0 2,1 1,9 2,2 1,8 3k3 1:X 280 340 1,6 30 4,0 11 40 50 80 SC Gain SC Freq 1k8 1k5 1k1 800 570 HP 430 ms -0,3 -0,3 LP -1 6,0 -12 -5 -2 60 300 14 3,0 18 20 MS Mode 16 2,
dB dB Feed Forward Lo Hi Direct % Com 2k0 0,5 1,5 2,0 Gain Compressed 100 Hz 0 1k0 3,5 500 dB 4,5 x10 12 24 21 19 Transformer 11 10 8,0 -12 25 -5 -2 Soft Clip dB Auto Fast 1,2 1,3 1,4 1,1 Ratio 16 dB 14 On 3,0 1,7 5,5 8,0 On Hz 5,0 6,0 2k0 11 9,5 8,5 4307,5 2,4 12 4,0 2,1 1,9 2,2 1,8 3k3 1:X 280 340 1,6 30 4,0 11 40 50 80 SC Gain SC Freq 1k8 1k5 1k1 800 570 HP 430 ms -0,3 -0,3 300 LP -1 60 6,0 -12 -5 -2 75 100 1
dB dB Feed Forward Lo Hi Direct 10 Dir % Com Hz 0,5 1,5 2,0 Gain 2k0 0 1k0 3,5 500 300 220 dB 4,5 x10 12 24 21 19 Transformer 11 10 8,0 -12 25 -5 -2 Soft Clip dB Auto Fast 1,2 1,3 1,4 1,1 Ratio 16 dB 14 On 3,0 1,7 5,5 8,0 On Hz 5,0 6,0 2k0 11 9,5 8,5 4307,5 2,4 12 4,0 2,1 1,9 2,2 1,8 3k3 1:X 280 340 1,6 30 4,0 11 40 50 80 SC Gain SC Freq 1k8 1k5 1k1 800 570 HP 430 ms -0,3 -0,3 300 LP -1 60 6,0 -12 -5 -2 75 100
dB dB Feed Forward Lo Hi Direct 10 % Com Hz 0,5 1,5 2,0 Gain 2k0 HP -12 Transformer 24 21 19 25 -5 -2 Soft Clip dB 1,1 16 dB 14 On 3,0 5,5 8,0 30 4,0 11 40 50 80 1,7 On Hz 5,0 6,0 2k0 11 9,5 8,5 4307,5 2,4 12 4,0 2,1 1,9 2,2 1,8 3k3 1:X 280 340 1,6 14 3,0 18 20 MS Mode 16 2,0 1,5 1,0 Active Gain Reduction Soft Clip 18 1,5 16 2,0 14 3,0 Channel Link 20 1,0 12 4,0 11 Lo 1,0 +20 2,7 9,5 8,5 7,5 6,0 5,0 +18 +15 +11
dB dB Feed Forward Lo Hi Direct 10 Dir % 2k0 0,5 1,5 2,0 Gain Compressed Hz 0 1k0 3,5 500 dB 4,5 x10 12 24 21 19 Transformer 11 10 8,0 -12 25 -5 -2 Soft Clip dB Auto Fast 1,2 1,3 1,4 1,1 Ratio 16 dB 14 On 3,0 1,7 5,5 8,0 On Hz 5,0 6,0 2k0 11 9,5 8,5 4307,5 2,4 12 4,0 2,1 1,9 2,2 1,8 3k3 1:X 280 340 1,6 30 4,0 11 40 50 80 SC Gain SC Freq 1k8 1k5 1k1 800 570 HP 430 ms -0,3 -0,3 300 LP -1 60 6,0 -12 -5 -2 75 100 15
dB dB Feed Forward Lo Hi Direct 10 % 2k0 0,5 1,5 2,0 Gain Compressed Hz 0 1k0 3,5 500 dB 4,5 x10 12 24 21 19 Transformer 11 10 8,0 -12 25 -5 -2 Soft Clip dB Auto Fast 1,2 1,3 1,4 1,1 Ratio 16 dB 14 On 3,0 1,7 5,5 8,0 On Hz 5,0 6,0 2k0 11 9,5 8,5 4307,5 2,4 12 4,0 2,1 1,9 2,2 1,8 3k3 1:X 280 340 1,6 30 4,0 11 40 50 80 SC Gain SC Freq 1k8 1k5 1k1 800 570 HP 430 ms -0,3 -0,3 300 LP -1 60 6,0 -12 -5 -2 75 100 150 Re
dB dB Feed Forward Lo Hi Direct 10 Dir % 2k0 0,5 1,5 2,0 Gain Compressed Hz 0 1k0 3,5 500 dB 4,5 x10 12 24 21 19 Transformer 11 10 8,0 -12 25 -5 -2 Soft Clip dB Auto Fast 1,2 1,3 1,4 1,1 Ratio 16 dB 14 On 3,0 1,7 5,5 8,0 On Hz 5,0 6,0 2k0 11 9,5 8,5 4307,5 2,4 12 4,0 2,1 1,9 2,2 1,8 3k3 1:X 280 340 1,6 30 4,0 11 40 50 80 SC Gain SC Freq 1k8 1k5 1k1 800 570 HP 430 ms -0,3 -0,3 300 LP -1 60 6,0 -12 -5 -2 75 100 15
REFERENCE - Threshold Offset The analog audio level of the alpha compressor depends on the studio environment it is used in. In the majority of cases it depends on the DA converter used, because the output stages of the converter determine the analog level. As there is no binding norm for it, this level can be at +4dB, +6dB, +10dBu, +12dBu or even +15dBu. To make sure that the Threshold controller actually covers its complete adjustment range it can be adjusted to those different levels.
Attack Here a Burst signal (a sine tone that is boosted by 12 dB for a period of 100ms) is used to demonstrate the effectiveness of the Attack controller. The different curves show how fast this level jump is reduced by 4dB. On fast settings the reduction takes only a few milliseconds, on longer settings the reduction does not only take longer but it is also smaller. Therefore on fast Attack settings the Gain reduction is always higher than on longer settings.
Release This figure is based on a very fast Attack time; the Gain reduction is at -7dB. The Burst lasts for 25ms and then follows the Release phase with time parameters of different length. The linear characteristic of the Release curve is very easy to see here. Because of the utilized circuit the Attack time must always be added to the Release time. The advantage is that in combination with long Attack settings you can use even the fastest Release settings without generating unwanted artifacts.
Ratio Feedback The alpha compressor works with a soft knee characteristic and increasing Ratios at rising Gain reduction values. The scale on the front panel is based on a measured Gain reduction of 6dB. Strictly speaking, the Ratio values become noticeably higher on stronger reductions: When there is 17dB of Gain reduction the ratio value shifts from the printed 1:2,5 to 1:4,5 after all.
EQ Gain Low For this measurement the center frequency was set to 1,8kHz and the EQ Gain controller was set to different positions between 0 and full left (-3dB). The diagram shows the effectiveness of the filter: The lower frequencies are boosted up to 3dB, at the center frequency they cross zero, and the higher frequencies are cut up to 4,5dB. Depending on the setting of the EQ Gain the level might have to be adapted with the Gain controller.
EQ Frequency This diagram shows a variation of center frequencies with the EQ Gain controller fully turned clockwise (HI). The x10 button shifts the complete frequency area by a factor of 10. With settings in the border areas of the covered frequencies it is also possible to realize “almost” shelving filters, but in these cases the level has to be adapted with the Gain controllers.
SC Low Pass This diagram shows some settings of the Sidechain frequency controller (SC Freq) in Low Pass mode (LP). If the filter is set at 100Hz (dark blue curve) for example, full Gain reduction will still occur at these 100Hz and the high frequencies will have lesser influence the higher they get. Therefore in this mode of operation the filter should always be set to the highest frequency you just about want the compressor to react to.
Mix This measurement diagram shows a fade from the original to the compressed signal (Direct and Compressed buttons active). The Gain controller was set at 0dB, which is also the reason for decreasing levels in the more clockwise areas of the controller range. In case that only the direct or alternatively only the compressed signal is switched in, the Mix controller does not have any influence on the level. dBu +20 +18 +16 +14 +12 +10 +8 +6 +4 +2 -0 -2 -4 -6 -8 -10 -12 -14 -16 -18 -20 -20 -17.5 -15 -12.
APPENDIX - Level Problems No Signal This problem might be caused by balanced wiring. If the signal almost completely drops when the alpha compressor is activated, it is probable that a pin of the XLR connector at the input is not connected. As the input stages feature transformers, both pins have to be connected. The classic case for this problem would be a balanced XLR connection that is connected to an unbalanced output that only uses ground and pin 2. Connecting pin 3 to ground should solve this problem.
Frequency Response: <10Hz – 200kHz (-0.5dB) THD+N @+15dBu, 20Hz-22kHz: Stereo Mode (Direct) Stereo Mode (Compressed) MS Mode (Direct) MS Mode (Compressed) 0.0039% 0.009% 0.014% 0.034% Noise Floor, 20Hz-20kHz (A-weighted): Stereo Mode (Direct) Stereo Mode (Compressed) MS Mode (Direct) MS Mode (Compressed) -95.8dBu -89.3dBu -95.6dBu -92.
Warranty Conditions and limitations The alpha compressor is covered by a limited warranty for a period of 5 years against defects in parts and labor from the date of purchase. Natural wear is not covered by this warranty. elysia will remedy problems caused by material or workmanship either by repair or replacement to restore the product to full performance without charge for parts and labor. Repairs or replacements will not extend the warranty period.
dB dB 0,01 % dB 12 HP -12 24 21 19 25 -5 -2 Soft Clip dB Transformer 10 8,0 11 6,0 LP 1,1 16 dB 14 On 3,0 5,5 8,0 30 4,0 11 40 50 80 1,7 On Hz 5,0 6,0 2k0 11 9,5 8,5 4307,5 2,4 12 4,0 2,1 1,9 2,2 1,8 3k3 1:X 280 340 1,6 14 3,0 18 20 MS Mode 16 2,0 1,5 1,0 Active Gain Reduction Soft Clip 18 1,5 16 2,0 14 3,0 Channel Link 20 1,0 12 4,0 11 Lo 1,0 +20 2,7 9,5 8,5 7,5 6,0 5,0 +18 +15 +11 Thresh dB dB -3 10 Dir 50
„Let there be sound“ TCHAIKOVSKY‘S NEWS And there was sound.
