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5

Machine Head

Operation Safety

Indicators and meters:

M

ACHINE

H

EAD

is equipped with PPM displays for input and

output levels. The first LED of each input and output meter is a
signal (S

IG

.) LED which illuminates when a compatible digital

data stream is present at the inputs. The LEDs are a first indi-
cator to check the data stream. If the LEDs do not illuminate the
data stream is interrupted or invalid.

The top LEDs of each input and output meter indicate if a

digital clip has occured at the inputs or due to processing within
M

ACHINE

H

EAD

. Clipping that is already present at the inputs will

also be shown on the O

UTPUT

PPM chains. 

The D

RIVE

LED chains display the drive or recording level that

is sent to the virtual tape. The values shown range from -10 dB
to +21 dB.

The philosophy behind the digital audio processors is that

they are designed to be operated like analogue units; there is
only one I

NFO

menu but no multi-function controls. The LCD

readout simply shows the current encoder positions and the
preset number. The encoders are built without clicks or detents,
so they feel like analogue pots. Our DSP platform uses two
Motorola 56002 DSPs running at 66 MHz. This enormous
computational power guarantees real-time operation where
sophisticated DSP algorithms will not be restricted by resource
limitations. The general concept is that each digital processor
should fulfill only one task, in the most effective way possible,
and with a minimum of controls and switches. As much as
possible should be automated to promote user-friendly opera-
tion – the external controls access only the sonically relevant
parameters. 

The housing of the M

ACHINE

H

EAD

has the standard 19"- EIA

format and occupies 1U (44.45 mm) in your rack. When instal-
ling the unit in a 19"-rack, the rear side of the unit needs some
support, especially in a touring case. 

The M

ACHINE

H

EAD

should not be installed near units which

produce strong magnetic fields or extreme heat. Do not install
the M

ACHINE

H

EAD

directly above or below power amplifiers.

Check that the voltage details quoted on the back panel

are the same as your local mains electricity supply. Use a
minus (-) screwdriver to set the voltage selector to the
voltage for the area in which the unit will be used. 

Never cover up the ventilation slots on the top of the unit.

If, during operation, the sound is interrupted or indicators
no longer illuminate, or if abnormal odor or smoke is
detected, or if liquids are spilled on the unit, immediately
disconnect the power cord plug and contact your dealer. 

Only clean your M

ACHINE

H

EAD

with a soft, lint-free cloth. 

S

IGNAL

-LEDs to verify data

stream

Clip-LEDs

Input and Output 
PPM metering

D

RIVE

-LED displays recording

level

The DSP Platform:
Enormous computational
power guaranteeing real-
time operation

„Analogue“ control feeling

User-friendly programmed
software

Summary of Contents for 9737

Page 1: ...Manual Digital Tape Saturation Processor Machine Head Model 9737 ...

Page 2: ...PL Limitations of Liability In no event will SPL be liable for any damages including loss of data lost profits cost of cover or other special incidental consequential or indirect damages arising from the use of the unit however caused and on any theory of liabi lity This limitation will apply even if SPL or an authorized dealer has been advised of the possibility of such damage SPL electronics Gmb...

Page 3: ...B Team I would like to start with my thanks to all our staff who created what is to be described here Special thanks go to Kai Lukas from Lukas Hartmann Soundart Jörg Houpert and Klaus Peter Webersinke from Spectral Design as well as Harald Obenland from Octum electronics The importance of their exceptional qualification and talents cannot be overesti mated Our products are often tested and compar...

Page 4: ...ion effects for full scale input signals and to deliver full scale output signals afterwords The intensity of high frequency damping varies from one tape to another and is therefore fully adju stable one the MACHINE HEAD It is now also possible to make use of extreme saturation effects without high frequency damping at all In fact MACHINE HEAd provides all the benefits of analogue recording withou...

Page 5: ... The general concept is that each digital processor should fulfill only one task in the most effective way possible and with a minimum of controls and switches As much as possible should be automated to promote user friendly opera tion the external controls access only the sonically relevant parameters The housing of the MACHINE HEAD has the standard 19 EIA format and occupies 1U 44 45 mm in your ...

Page 6: ...ect your computer with the MACHINE HEAD via a serial port with a standard Z modem cable RS 232 for PC and RS 422 for MAC 2 Open a terminal program like Hyperterminal on PC and make the following adjustments Baud rate 9600 Stop bit 1 Parity none Data bit 8 Handshake no Transfer mode ZMODEM 3 Switch on the MACHINE HEAD and depress both PRESET UP and PRESET DOWN until the LC display says wait for Zmo...

Page 7: ...e audio signal that passes the input electronics of an analogue tape machine is first processed by the recording equalizer The high frequencies are boosted to compensate for the level loss of those frequencies during magnetization and to improve the signal to noise ratio A high frequency bias current is afterwards added to the signal to linearize the non linear hysteresis transfer curve of the mag...

Page 8: ...he INPUT PPM meters displays the actual input level after theINPUT GAIN control In practise you will start with the INPUT GAIN set to 0dB For most applications this is the appropriate setting If your source material is of ver y low level or not normalized yet you can use the INPUT GAIN control to drive the source material near full scale If you are processing full scale material it may be neces sa...

Page 9: ... the process for instant comparison between unprocessed and processed signal Internally the MACHINE HEAD has to create a headroom especially when processing full scale material to compute the tape saturation algorithm With a DRIVE set to true 0 you will loose 7dB headroom As a starting position the DRIVE is there fore set to 0 which is equivalent to 7dB of recording level Therefore you also have n...

Page 10: ...loudest part of the audio file being processed and watch the CLIP LEDs With the HIGH TAPE SPEED switch you can change the speed of the vitual tape from standard tape speed 15ips to high tape speed 30ips When HIGH TAPE SPEED is activated the algorithm simulates the pre emphasis for high speed recording The upper mid and high frequencies as well as the harmonical content gain better resolution and f...

Page 11: ...ss STORE for one second The LED starts to flash indicating that the STORE mode has been activated The LC display now shows the values of the presets including the BOOST function before the MACHINE HEAD was switched off the last time Use UP and DOWN to select a new preset number The status LED flashes shortly to indicate that the input depressing UP or DOWN is accepted Keeping UP or DOWN depressed ...

Page 12: ...arches for an input signal If both inputs are connected the AES EBU input will be selected first If you want to select the S P DIF input you have to call up the INFO pages IMPORTANT When selecting a new input allow the SIG LEDS to go out before stepping to the next input format Otherwise MACHINE HEAD may lose the data stream AES EBU input detected or no AES EBU input detected Press APPLY if AES EB...

Page 13: ...lay either shows 44 1 kHz 48 kHz or 32 kHz 4 Displaying the Audio Error flag NO no error detected YES error detected 5 Displaying the CRC Error flag NO no error detected YES error detected 6 Displaying the Channel Difference Error flag NO no error detected YES error detected 7 Setting or erasing the Copy Prohibit flag NO flag erased or not set YES flag set 8 Displaying the Original flag NO no orig...

Page 14: ...e out if you are working with a digital console that does not provide master inserts The UP and DOWN LEDS illuminate indicating that a volume change command is received You can also switch between presets with the MIDI program change command This can especially be useful when you are mastering a song for example that requires different settings for chorus refrain or bridge The APPLY LED illuminate...

Page 15: ... 110 Ohms S P DIF co axial 2 SPDIF 2 S P DIF input impedance 75 Ohms Wordclock In Through co axial BNC Wordclock in output impedance 75 Ohms MIDI In Through yes RS 232 yes RS 422 max 14V yes Clip display yes Input transformer AES EBU yes Output transformer AES EBU yes Relay Hard Bypass AES EBU yes Measurements AES EBU Jitter 1ns S P DIF Jitter 3ns Wordclock In Jitter 1 5ns Power supply Torroidal t...

Page 16: ...thorized SPL warranty repair facility in the country where purchased or to the SPL factory in Germany in the original packaging or a replacement supplied by SPL with all trans portation costs and full insurance paid each way by the purchaser or owner All remedies and the measure of damages are limited to the above services It is possible that economic loss or injury to person or property may resul...

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