Creative Emu 1820m Manual

							6 - Using High Sample Rates
Overview
E-MU 1820M/1820/1212M PCI Digital Audio System 111
6 - Using High Sample Rates
Overview
When operating at 88.2k, 96k, 176.4k and 192k sample rates, the mixer functionality 
and number of I/O channels are reduced. These changes are summarized in the 
following tables. All S/PDIF inputs and outputs are disabled at 176.4kHz and192kHz. 
The number of ADAT channels also decreases at the 88.2k/96k and 176.4k/192k sample 
rates (due to the bandwidth limitations of the optical components).
When using 88.2kHz, 96kHz, 176.4kHz or 196kHz sample rates:
The ADAT optical interface was originally designed to carry 8 channels at a 48kHz 
sample rate. We use the Sonorus® S/MUX™ standard to encode audio with higher 
sample rates onto the ADAT light pipe. In this multiplexing scheme, two ADAT channels 
are used to carry one 88.2k or 96k stream and four ADAT channels are used to carry one 
176k or 192k audio stream. In order to use the ADAT interface at these higher sample 
rates, you must have other equipment that supports the Sonorus S/MUX standard.
E-MU 1820 System at 88.2k/96k (1010 PCI Card & AudioDock)
All outputs remain active at 88.2k/96k, but the number of ADAT channels is reduced 
from eight to four (see above). There are two possible input configurations when using 
the E-MU 1820 system at 88.2k/96k as shown in the chart below. Basically, you have the 
option of using the (4) ADAT input channels or (4) Line Inputs (Line Inputs 2 and 3). 
At 88.2kHz/96kHz the headphone output parallels the Monitor output and is no longer 
independently assignable.
•Effect processors are disabled. (Output sends & returns are still available.)
•ADAT is reduced to 4 chan. at 88k/96k, & 2 chan. at 176k/192k.
•ASIO channels are reduced to 8 stereo ASIO channels at 88k/96k, 
and 4 stereo ASIO channels at 176k/192k.
•At 176.4k/192k, the number of physical inputs/outputs is reduced.
•At the 176.4k & 192k sample rates, S/PDIF optical is disabled.
E-MU 1820 Inputs/Outputs at 88.2kHz or 96kHz
SourceInputs 
(ADAT Option)Inputs 
(Line In Option)Outputs
ADAT404
S/PDIF 1222
S/PDIF 2222
Microphone22-
Line 1222
Line 2022
Line 3022
Line 4 out (monitor)--2
Headphone out--2 (monitor)
Total121218
ENote: Headphone 
Out is permanently 
linked to Monitor Out in 
96kHz mode. 
						

							6 - Using High Sample Rates
Overview
112Creative Professional
E-MU 1212M System at 88.2k or 96k (1010 PCI Card & I/O Card) 
When using the E-MU 1212 system at 88.2kHz or 96kHz you have two analog inputs 
and outputs and two S/PDIF inputs and outputs. The ADAT input/output channels are 
reduced from eight to four using the S/MUX standard. 
E-MU 1212M Inputs/Outputs at 88.2kHz or 96kHz
SourceInputsOutputs
ADAT44
S/PDIF22
Line22
Total88
ADOCK
ADOCK
4 Chan.
4 Chan.
4 Chan.
Input/Output - 88.2 kHz/96 kHz
ADAT enabled
Line In 2 & 3 enabled
or…
At the 88.2kHz/96kHz sample rates, all outputs are available but 4 inputs are lost. ADAT optical 
is also reduced to four channels. You have the option to enable either:
• ADAT Inputs
   or…
• Line Inputs 2 and 3 
						

							6 - Using High Sample Rates
Overview
E-MU 1820M/1820/1212M PCI Digital Audio System 113
E-MU 1820 System at 176.4kHz or 192kHz 
(1010 PCI Card & AudioDock) 
At the highest sample rate you have 4 inputs and 10 output channels.
There are four possible input configurations when using the E-MU 1820 system at 
176.4kHz or 192kHz. Each of the three options provides four input channels.
S/PDIF is not specified to operate at  176.4kHz/192kHz and so all S/PDIF inputs and 
outputs are disabled. The headphone output parallels the Monitor output and is no 
longer independently assignable, just like at 96kHz.
E-MU 1212 System at 176.4k/192k (1010 PCI Card & I/O Card)
At 176.4kHz or 192kHz, you have two 24-bit inputs and outputs. S/PDIF is not 
specified to operate at these rates and so all S/PDIF inputs and outputs are disabled. The 
ADAT input/output channels are reduced to two channels (S/MUX standard). 
•Microphone Input and Line 2 Input enabled
•Microphone Input and ADAT Input enabled (2-chan ADAT)
•Line 1 Input and ADAT Input enabled (2-chan ADAT)
•Line Inputs 1 & 3 enabled (allows use of turntable inputs at 192kHz)
E-MU 1820 Inputs/Outputs at 176.4kHz or 192kHz
Source
Inputs 
Mic & 
Line 3Inputs 
Mic 
& ADATInputs 
Line 1 
& ADATInputs 
Line 1 & 3
Total 
Outputs
ADAT02202
Microphone2200-
Line 100222
Line 200002
Line 320020
Line 4 out (monitor)----2
S/PDIF 100000
S/PDIF 200000
Headphone out----2 (monitor)
Total444410
E-MU 1212M Inputs/Outputs at 176.4kHz/192kHz
SourceInputsOutputs
ADAT22
S/PDIF 100
Line22
Total44 
						

							6 - Using High Sample Rates
Overview
114Creative Professional
or…
or…
Microphone & Line 3 Input enabled
Line Input 1 & ADAT Input enabled
Line Inputs 1 & 3 enabled
2 Chan.
ADOCK
2 Chan. 
2 Chan. 
ADOCK
ADOCK
2 Chan. 
or…
Microphone & ADAT Input enabled
2 Chan.
ADOCK
2 Chan. 
At the 176.4kHz or 192kHz sample rates, you sacrifice S/PDIF, line input 3, and line output 3. 
ADAT optical is reduced to two channels. You can choose one of the following options:
• Microphone Inputs & Line 2 Inputs  • Line Inputs 1 & ADAT
• Microphone Inputs & ADAT Inputs • Line Inputs 1 & 3 
						

							6 - Using High Sample Rates
Overview
E-MU 1820M/1820/1212M PCI Digital Audio System 115
Example: Selecting a 176/192k Session 
The possible input configurations are selected by choosing a session template 
containing the desired I/O from the New Session window. Once you have selected one 
of the three session types, you will not be able to change to another type without 
starting a new session.
1.Select New Session from the PatchMix DSP toolbar.
2.Choose the 176k/192k tab.
3.Select the Template that meets your requirements and click OK.
WDM Recording and Playback Behavior
WDM recording and playback is supported at all PatchMix sample rates. The behavior of 
the driver with respect to PatchMix sample rate is described below. 
When PatchMix and the WDM audio content (.WAV file format, playback and record 
settings in WaveLab. etc.) are both running at the same sample rate, and when a Wave 
strip or send is present in the PatchMix mixer configuration, WDM audio will be played 
or recorded “bit accurate” without sample rate conversion or bit truncation.
When running PatchMix at 44kHz/48kHz, if there is a mismatch between the WDM 
playback audio content and the PatchMix sample rate, sample rate conversion is 
performed, so that WDM audio will always be heard or recorded. Also, such non-native-
sample-rate audio is truncated to 16-bits.
When running PatchMix at 88.2kHz, 96kHz, 176.4kHz or 192kHz, WDM record or 
playback audio content must be running at the same sample rate as PatchMix. If the 
sample rates are mismatched, NO AUDIO will be produced or recorded. In other words, 
the WDM driver does not perform sample rate conversion of any kind when PatchMix is 
running at 88.2kHz, 96kHz, 176.4kHz or 192kHz.  
						

							6 - Using High Sample Rates
Overview
116Creative Professional 
						

							7 - Appendix
Sync Daughter Card Supplement
E-MU 1820M/1820/1212M PCI Digital Audio System 117
7 - Appendix
Sync Daughter Card Supplement
SMPTE Conversion

Warning: SMPTE and 
MTC do not provide 
sample sync for digital 
I/O. You must use Word 
Clock, S/PDIF or ADAT 
sync.One of the main functions of the Sync Daughter Card is to convert SMPTE (LTC) to 
MIDI Time Code (MTC) and vice-versa. The term “Host MTC” refers to MTC, which is 
generated or used by the host application (Cubase, etc.). MTC is also available at the 
MIDI jack on the back of the Sync Card.
SMPTE Options
When the Sync Daughter Card is installed in your system a SMPTE button in the 
PatchMix DSP mixer becomes visible. Pressing the SMPTE button brings up the SMPTE 
window.
SMPTE Features
•Conversion of SMPTE to MTC quarter-frame messages & full-frame messages.
Constant quarter-frame messages are generated with steady SMPTE data input.
Occasional MIDI full-frame messages are generated when SMPTE contains data dropouts.
•Conversion of MTC (quarter frame & full frame) messages from the host 
computer to SMPTE out.
Simultaneous SMPTE and MTC output when receiving MTC from the host computer
•Outputs SMPTE and MTC striping data.
SMPTE Start Time and type can be set via System Settings dialog box.
SMPTE Frame 
Rate SettingsSMPTE 
Start Time
SMPTE Status/
Error IndicatorsStart StripingStop
StripingOutput 
Level Flywheel 
Amount
Flywheel Mode
• Off         • Continuous
• Fixed      •1-time JamCurrent Time
Output
Source
Word Clock 
Termination  
						

							7 - Appendix
Sync Daughter Card Supplement
118Creative Professional
SMPTE Modes of Operation
Host Mode
The host computer is the source of synchronization. MTC messages are sent to the Sync 
Daughter Card from the computer application and converted into SMPTE. MTC is also 
output from the MIDI port on the Sync Daughter Card.
External Mode
SMPTE messages from SMPTE In are converted to MTC (quarter-frame messages) and 
sent to the host application. This happens automatically whenever LTC is received at the 
SMPTE input jack. Clean SMPTE data is also transmitted from SMPTE Out if “SMPTE 
(Regenerate)” is set.
Flywheel Mode
If the incoming SMPTE data is corrupted or missing frames, MTC code will continue to 
be output if “Flywheel mode” is enabled. The flywheel modes are described below.
Flywheel Modes
Mode (fps)Sets the transmitted frame rate when striping SMPTE.
SMPTE StripingEdit this field to set the start time in hours:minutes:seconds:frames for 
striping SMPTE. 
Stripe ButtonInitiates SMPTE Time Code generation at the SMPTE output beginning at 
the time set in the striping display.
Stop ButtonStops SMPTE striping. This button also stops SMPTE when One-Time Jam 
Sync has been initiated.
Flywheel ModeSelects one of the four Flywheel modes. See the descriptions below.
Output LevelSets the SMPTE output level from -10dBV (consumer) to +4dBu (pro).
FLY/JAM FramesIf flywheel mode is on and a dropout is detected this is the number of fly-
wheel frames that will be output before the sync card stops and chases.
Word Clock 
TerminationTurns word clock termination on or off. Except in special cases, this con-
trol should normally be left on. See “
Word Clock In/Out”.
SMPTE/MTC 
Output SourceThis control selects the source of the SMPTE output jack. The choices are: 
Host MTC or the SMPTE Input jack (to regenerate SMPTE).
OffUpon any dropout, MTC stops and the Sync card monitors the input for 
valid code. If valid code is again received, it chases and relocks.
Fixed 0-127Upon any dropout, MTC continues outputting Quarter-frame messages 
at the same rate (flywheeling). When a dropout is detected, this is the 
number of frames that will be output before the Sync card stops output-
ting MTC and monitors the input for valid code. If valid code is again 
received, it chases and relocks.
ContinuousUpon any dropout, MTC continues outputting Quarter-frame messages 
at the same rate (flywheeling). The Sync card monitors the input for valid 
code and continues flywheeling until valid code is received, then relocks.
1-Time Jam SyncUpon any dropout, MTC continues outputting Quarter-frame messages 
at the same rate (flywheeling) without monitoring the SMPTE input until 
the Stop button is pressed. 
						

							7 - Appendix
SMPTE Background
E-MU 1820M/1820/1212M PCI Digital Audio System 119
Stripe Mode
This mode is used to record SMPTE time code onto an audio track of another recorder. 
SMPTE is output when the Start button is pressed in the System Settings menu and 
begins at the time set by the Start Time setting. MTC is also simultaneously output from 
the Sync Daughter Card MIDI out. SMPTE and MTC will continue to be output until the 
Stop button is pressed. See Striping SMPTE
.
SMPTE Background
SMPTE time code was standardized way back in 1969 by the Society of Motion Picture 
and Television Engineers as a way to mark frame numbers on video tape.
Using SMPTE, a particular location can be precisely located by simply entering the 
appropriate time code number which is expressed in Hours, Minutes, Seconds, Frames 
and Subframes. This is possible because each frame of SMPTE time code contains 
absolute location information expressed in digital form.
There are two types of SMPTE time code: Vertical Interval Time Code (VITC), which is 
used on video tape and Longitudinal Time Code (LTC) or audio time code. VITC is 
strictly used for video and has the advantage of being able to be read while the video 
deck is paused. LTC can be recorded on the audio or sync tracks of video tape and can 
thus be used in audio or video work.
Longitudinal time code is the type of SMPTE used on the Sync Daughter Card. It 
contains 80 bits of information per frame. An audio SMPTE frame is divided into 80 
“bit cells”. A voltage change during a bit cell period constitutes a digital “1” and no 
change during a bit cell period constitutes a digital “0”. In addition to the location bits, 
there are user bits that may contain information about tape reel numbers, bits dealing 
with video information, and a 16-bit sync word at the end of the frame.
There are four types of SMPTE time code in general use: 24, 25, 30 frame-per-second 
and 30 drop-frame. In general, you should choose one rate (30 non-drop is common in 
audio) and stick with it for initial recording and later editing.
The four frame rates are all straightforward except 30 drop-frame. The 30 df rate came 
about because the US color video frame rate is actually 29.97 frames/sec instead of 30 
frames/sec. This adds up to an error of 108 frames each hour relative to “wall clock” 
Types of SMPTE
Type Use Hours Minutes Seconds Frames
24 frame US Film 00-23 00-59 00-59 00-23
25 frame Euro. Film + Video 00-23 00-59 00-59 00-24
30 drop-frame US & Japan Color Video 00-23 00-59 00-59 00-29
30 non-drop  US & Japan B/W Video 00-23 00-59 00-59 00-29
Frames Seconds HoursFrames Seconds MinutesMinutes
Hours
Start
FrameEnd
Frame 10 20 30 40 50 60 70
80
80 Bit Cells per FrameBit
Cell
=0
=1
Bit
Cell
SYNC WORDSMPTE
Time
Code 
						

							7 - Appendix
SMPTE Background
120Creative Professional
time! (A one hour program would actually be 59 minutes and 56.4 seconds long.) Drop 
frame was designed to correct this time difference. In 30 Drop Frame, every minute 
except 00-10-20-30-40-50 have the first two frames, 00 and 01, “dropped”, hence the 
name drop-frame.
Why use SMPTE?
SMPTE sync, although well over 30 years old, has the advantage of being able to be 
recorded as an audio track. This allows it to be used with virtually any kind of recording 
equipment from tape recorders to computer-based digital audio recorders. You can even 
buy phonograph records with a SMPTE stripe!
SMPTE was designed in the days when tape dropout was a common occurrence and so it 
was designed to convey “absolute” location information. Since each frame of SMPTE 
code provides its own unique identification, it provides the ability for a receiving device 
to recover from data dropout. In addition, edits can be performed in the middle of a 
song with just a few seconds of pre-roll before the punch-in point. SMPTE is also 
standardized, which means that code generated on different makes of equipment will 
be compatible with each other. SMPTE also has fairly good resolution, especially at the 
subframe level. You’ll be happy to know that the Sync Daughter Card resolves to the 
subframe level. The chart below shows subframe accuracy at the three frame rates.
Striping SMPTE
Printing SMPTE to a track is called striping (as in stripe). SMPTE time code is recorded 
on an unused audio track of another recorder, then played back into the Sync Daughter 
Card. The Sync Daughter Card passes the location information on to the host computer 
as MTC quarter-frame data to be used by an application such as an audio recorder or 
sequencer.
SMPTE is usually recorded at about -3 VU on semi-pro gear, -10 VU on professional gear 
and 0 VU on video gear. Experiment to find the optimum levels. When printing to a 
time code track of a video deck, be careful. The time code playback head locations on 
video decks are not standardized and can cause gross timing errors. Time code which is 
striped on an audio track will always be in sync with the picture. SMPTE code is tradi-
tionally recorded on the right channel of a video recorder.
Avoiding SMPTE problems
Problems in reading SMPTE time code can often be related to poor quality code on the 
tape. Poor quality code can be caused by a number of problems, the most common 
being dirty or misaligned heads, amplifier clipping, or too many generations of audio 
dubbing. Other problems can be caused by running the SMPTE signal through signal 
processing devices such as Limiters, Reverbs, Harmonizers, etc. (Don’t laugh, it has been 
done!) In fact, many video decks have built in AGCs (Automatic Gain Controls) which 
will ruin the SMPTE signal if the input level is too high. Always check playback to insure 
that the time code is usable. In general, no signal processing should be used on the 
SMPTE signal. SMPTE code is delicate and should be treated as such.
SMPTE Subframe Resolution
Frames-per-secondResolution
24 fps.521 mS
25 fps.500 mS
30 fps.417 mS