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6 - Sample Edit

Compressor

O The Start and End points

Compressor

The Digital Compressor is a digital (non-realtime) equivalent of an analog

are “remembered” from module

dynamic range compressor with attack and release times, adjustable

to module so that you can

threshold, adjustable ratio, and three modes of operation.

perform successive operations

 

on the same section of the

v To Compress a Sample:

sample.

 

1.Press the Sample Edit key. The LED illuminates and the main sample edit screen appears.

2.Select the sample that you want to compress using the Data Entry Control, INC/DEC keys, or the numeric keypad.

3.Press the Tools 3 function key (F4). Another row of function keys appears.

If the sample is stereo, a 4. Press the Comprsr function key (F2). The following screen appears.

pop up dialog box will ask you

A waveform display appears with several controls.

to select left, right or both sides.

 

 

 

 

Waveform Display

 

 

 

Editing

 

 

Fields

 

 

 

 

Vertical

Zoom

Zoom In

Zoom In

Scale

Out

at Start

at End

Magnifier

 

Point

Point

OHolding down the Enter Editing Fields: Move the cursor to the desired field to change the

key while turning the Data Entry

Start and End points of the sample section to be compressed.

Control allows “fine tuning” of

Magnification: Adjusts the vertical scale for 1x, 2x, 4x, or 8x

the value by one number per

magnification. Pressing the button repeatedly rotates through the

click.

4 options.

 

• The Zoom controls also

Zoom Start: Magnifies the waveform to display finer detail around

change the editing resolution.

the Start point of the selected section.

 

 

Zoom End: Magnifies the waveform to display finer detail around

 

the End point of the selected section.

 

Zoom Out: Reverses the effect of Zoom Start & Zoom End.

 

5. Specify the Start and End points for the section of the sample to be

 

processed.

 

6. Press OK when you have selected the desired section or press Cancel to

 

cancel the operation.

EOS 4.0 Software Manual 221


6 - Sample Edit

Compressor

7. If you pressed OK, the following screen appears.

Mode

RMS: Root-mean-square or an “average of the magnitude of the signal”. RMS represents the “true” energy content of a signal.

Peak: Uses the peak amplitude of a signal to determine the amplitude. The peak amplitude is a meaningful measurement in a digital system because of the 96 db (16-bit) headroom limit.

Threshold

Above: Only signal levels above the threshold % will be affected by the compressor.

Center: Signal levels above as well as below the threshold % will be affected by the compressor.

Below: Only signal levels below the threshold % will be affected by the compressor.

%: Determines the threshold level as a percentage of 100% of 16-bits.

Compression Ratio

Determines the amount of compression or expansion. Ratios of greater than 1:1 compress dynamic range. Ratios of less than 1:1 expand dynamic range.

Compression: Reduces the amount of dynamic range. Levels remain more constant.

Expansion: Expands the amount of dynamic range. Changes in level are exaggerated.

Attack Time

Determines how quickly the gain will be turned down. The attack time is variable from 1 to 999 milliseconds.

Release Time

Determines how quickly the gain will be turned up. The release time is variable from 1 to 999 milliseconds.

222 E-MU Systems

6 - Sample Edit

Compressor

8.Press OK when you have set the desired options or press Cancel to cancel the operation.

 

 

 

Compressor Threshold

 

Only signal levels ABOVE

 

 

100%

 

 

 

1:1

 

 

 

 

 

2:1

 

 

 

 

 

 

 

 

the Threshold percentage

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

will be affected by the

 

 

50%

 

 

 

10:1

 

 

 

 

 

compressor.

Threshold

 

 

 

 

 

 

 

 

 

 

 

 

 

 

0%

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Above

 

 

 

 

 

 

 

 

 

 

Signal levels ABOVE as

 

 

100%

 

 

 

1:1

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

well as BELOW the

 

 

 

 

 

 

 

 

2:1

Threshold percentage will

Threshold

 

50%

 

 

 

10:1

be affected by the

 

 

 

 

 

 

 

 

 

compressor.

 

 

 

 

 

 

 

 

 

0%

Center

Only signal levels BELOW

100%

 

 

 

 

 

 

 

 

 

 

 

 

the Threshold percentage

Threshold

 

 

 

 

 

 

 

will be affected by the

50%

 

 

10:1

 

 

compressor.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

2:1

 

 

 

 

 

 

1:1

 

0%

 

 

 

 

 

 

 

Below

EOS 4.0 Software Manual 223



6 - Sample Edit

Using the Digital Compressor

Using the Digital Compressor

Limiter

A limiter prevents the signal from exceeding a preset level (threshold).

Signal levels below the threshold will be unaffected.

Set the controls as follows:

Threshold: Above, XX% (where XX is the limit point).

Ratio: >10:1

Attack Time: 1 mS

Release Time: approximately 100 mS

Musical Compression (e.g. Guitar)

This type of compression tries to keep the volume constant, generally to increase the sustain of the instrument. As the note dies away, the compressor will boost the level in an effort to keep the level constant.

Set the controls as follows:

Threshold: Center, XX% (where XX is the compression point).

Ratio: approximately 4:1

Attack Time: 1 mS to 100 mS

Release Time: > 100 mS

Noise Reduction

Noise reduction will reduce low levels even further in the assumption that low levels are noise.

Set the controls as follows:

Threshold: Below, approximately. 30%

Ratio: approximately 0.7:1

Attack Time: approximately 100 mS

Release Time: approximately 100 mS

224 E-MU Systems


6 - Sample Edit

Parametric Equalizer

O The Start and End points

Parametric Equalizer

Parametric EQ allows you adjust the individual parameters of the filter.

are “remembered” from module

Boost/Cut controls “how much” of the signal will be boosted or cut. Center

to module so that you can

Frequency sets the center frequency to be boosted or cut, and the

perform successive operations

Bandwidth control sets the width of the band to be boosted or cut. The

on the same section of the

three parameters are diagrammed on the following page.

sample.

The parametric equalizer is a digital (non real-time) equivalent of an analog

 

 

equalizer with +12 dB of boost and a whopping -48 dB of cut. Center

 

frequency and bandwidth controls are accurate, precise and have an excep-

 

tionally wide range.

OThe left and right cursor v To Filter a Sample:

buttons will change the start

1.

Press the Sample Edit key. The LED illuminates and the main sample

and end points so that they fall

 

edit screen appears.

on positive zero-crossing points

 

2.

Select the sample that you want to equalize using the Data Entry

in the waveform. This will

minimize clicks in the sound

 

Control, INC/DEC keys, or the numeric keypad.

when processing only part of a

3.

Press the Tools 3 function key (F4). Another row of function keys

sample.

 

appears.

 

4. Press the ParEQ function key (F3). The following screen appears.

 

 

 

 

 

 

 

 

 

 

OIf the sample is stereo, a The Select Section display controls are identical to the controls in

pop up dialog box will ask you

Truncate. See Truncate for a full description of the controls.

to select left, right or both sides.

5. Specify the Start and End points for the portion of the sample to be

 

 

EQ'ed using the Data Entry Control, left/right cursor keys, INC/DEC

O Holding down the Enter

keys or the numeric keypad.

6. Press OK to continue on to the next page of options or Cancel to cancel

key while turning the Data Entry

the operation.

Control allows “fine tuning” of

 

the value by one number per

 

click.

 

EOS 4.0 Software Manual 225