SWISS SOUNDN E W S A N D V I E W S F R O M S T U D E R SWISS SOUND

A PUBLICATION OFSTUDERPROFESSIONALAUDIO AG

DECEMBER 1995No 36

In this issue:

STUDER at inter-national exhibitionspage 2

Application of theMADI format inMatrix Routerspage 3

Symposia andSeminarspage 6

News from ourRepresentativespage 7

News from theSTUDER worldpage 8

STUDER D19MicVALVEpage 9

New CD-Recorderfor universal usepage 11

NOB OB-Van formultichannelTV recordingpage 13

In memoriamEugen Spörripage 14

2

SWISS SOUND 36

Bruno Hochstrasser

SWISS SOUND

EditorKarl Otto Bäder

Desktop PublishingMax Pfister

Contributors of this issueBernd FuhrmannBruno HochstrasserRudolf KiseljakDavid RothAchim StrauchDr. h. c. Willi Studer

Please mail your letters to:SWISS SOUND STUDERAlthardstrasse 30CH-8105 RegensdorfSwitzerland

Reprint permitted with refer-ence to SWISS SOUND(please send a copy to theeditor)

Printed in Switzerland10.26.2050 (Ed. 1295)

A Harman International Company

Dear SWISS SOUND rDear SWISS SOUND rDear SWISS SOUND rDear SWISS SOUND rDear SWISS SOUND readereadereadereadereader,,,,,

again and we could set future orientated mile-stones with the introduction of new digital prod-ucts and system components. We are very muchlooking forward to presenting to you the resultsof our efforts in the coming months. The next is-sue of the SWISS SOUND which will be pub-lished at the upcoming AES Convention in Co-penhagen will bring you the details.

I would like to thank you sincerely for your faith-ful and constructive ccoperation with our com-pany in this past year. For the coming year I dowish you also in the name of all my colleaguesa successful, happy, and prosperous 1996.

Bruno Hochstrasser

I am very pleased to present to you today ourmagazine SWISS SOUND in a slightly differentform. You will see that in addition to our techni-cal articles which enjoy a high reputation amongour readership also news from the market andfrom the «STUDER-Family» are part of the pub-lication. I sincerely hope that you will appreci-ate this new layout.

We at STUDER Professional Audio AG are proudto state that we had a very successful businessyear. The integration into the Harman Interna-tional Industries‘ group showed positive results.Major organizational changes in Regensdorfhave led to cost reduction and to efficiency im-provements. Our R&D department was enlarged

STUDER aSTUDER aSTUDER aSTUDER aSTUDER at intert intert intert intert internananananationaltionaltionaltionaltionaleeeeexhibitionsxhibitionsxhibitionsxhibitionsxhibitionsExhibitions are always an important occasion forSTUDER to show new products and - most im-portant of all - to interact with our customers.Consequently the STUDER booth at the 99th AESConvention in New York was again the meetingpoint for experts from all over the world.

STUDER presented on this occasion for the firsttime the MO Recorder D424 (Swiss Sound 35)and the D19 MicVALVE (described on page 9of this issue). In addition the show presented theopportunity to demonstrate for the first time inthe US the D940 Digital Mixing Console.

Another major exhibition was the InterBEE inTokyo (see front page).

Smaller but very compact was the exhibition inconnection with the 17th Nordic Sound Sympo-sium in Bolkesjo (Norway). This remote place inthe Telemark province, two hours by car fromOslo and situated in a beautiful landscape, is thevenue every second year for the gathering of 250experts from all over Scandinavia which cometogether to get informed with respect to the new-est developments in professional audio.

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SWISS SOUND 36

1 2 3 4 m 1 2 3 4 n

1234

p

Input Matrix Output Matrix

X X

AES/EBU Format Subframe:

Preamble Audio sample word

MADI SYNCMADI A/BMADI ACTIVEMADI CHANNEL 0

MADI Frame Period:

channel 0 channel 1 channel 54 channel 55

V U C P

0 1 2 3 4 27 28 29 30 31

Fig. 1: Broadcast Routing with separate Input and Output Matrix.

Karl Otto Bäder

ApplicaApplicaApplicaApplicaApplication of the MADI-Ftion of the MADI-Ftion of the MADI-Ftion of the MADI-Ftion of the MADI-Fororororormamamamamatttttin Main Main Main Main Matrtrtrtrtrix Routersix Routersix Routersix Routersix Routers

Digitale Systems

1. The Development of MatrixRouters

Since the early days of radio signal distributionof both, internal and external connections, wasone of the main tasks of a broadcasting house.What started as a patch bay - similar to thetelephone connection systems of the early days- developed to relay driven and even later elec-tronically switched connection arrays. Each con-nection had its own switching point.

As experience showed that only a certain numberof all possible switching points were active at atime concentration strategies were introduced(also following the contemporary trends in tele-phone switching technology). The theoreticalnumber of switching points Z according to:

Z = m (inputs) x n (outputs)

was reduced due to a configuration with sepa-rate input and output switching matrices to:

by Karl Otto Bäder

Z = (m x p) + (n x p)

with p being the number of interconnectionsbetween both matrices (Fig. 1).

This basic circuit was initially used also withthe introduction of digital signals; but soon ideasfor further concentration came to life, especiallyby using time multiplex technologies. If it wouldbe possible to find a multiplex format whichcould also be useable for the signal transportwithin the broadcast organization, then not onlythe matrix router could be simplified, but alsothe - so far very expensive - cabling.

In the meantime such a format does exist, it iscalled MADI.

2. The MADI FormatThe MADI standard (Multichannel Audio DigitalInterface) is a derivate of the industry standardFDDI (Fibre Distributed Digital Interface). Thisstandard is used in data communication with atransfer rate of 125 MBit/sec over coax cable(up to 200 m distance) or over glass fibre (up to2000 m). The possible length depends on thestructure of the interfaces and the line equaliza-tion. The input word is chopped into 4 bit blocks,and each block will be then transcoded into a5 bit block according to a given truth table.This increase in block length has the result toachieve a NRZI coding. By the 4:5 extension anet data rate of 100 MBit/sec is at the user‘sdisposal.

In the MADI format this allows the transfer of 56AES3 subframes with 32 bit each. Under theassumption that also a +12,5 % varispeed de-viation should be permitted, the data rate iscomputed according to the following formula:

(48 kBit/s + 12,5%) x 32 [bit] x 56 [channels] =96,768 MBit/s

This is a good yield of the given capacity [1], [2].

Fig. 2: MADI-Format

4

SWISS SOUND 36IN

PUT

MUL

TIPL

EXIN

G ANALOGINPUTS

MADI

AESINPUTS

MADI

AES &ANALOGINPUTS

MADI

ANALOGOUTPUTS

MADI

AESOUTPUTS

MADI

AES &ANALOG

OUTPUTS

MADI

OUT

PUT

DEM

ULTI

PLEX

ING

GA

THER

ING

OF

SOUR

CES

rINPUTS

MADI

qINPUTS

MADI

pINPUTS

MADI

LOCALOUTPUTS

MADIDS-D DMUX

OU

TPUT

DIS

TRIB

UTIO

N

DS-D DMUX

DS-D DMUX

DS-D DMUX

LOCAL SELECTION

LOCALOUTPUTS

MADIDS-D DMUX

LOCAL SELECTION

LOCALOUTPUTS

MADIDS-D DMUX

LOCAL SELECTION

CENTRAL ROUTINGNODE

SYSTEM ROUTINGCONTROL

DS-PRFRAMES

DS-MCMASTER CLOCK

Clock reference, distributedto all equipment

ARCHITECTURE OF THE MADI BASED ROUTING SYSTEM

DIRECT MADI INPUTS DIRECT MADI OUTPUTS

p

p+q

p+q+r

DS-D MUX

DS-D MUX

DS-D MUX

DS-D MUX

DS-D MUX

DS-D MUX

56

It is easy to understand that this format simpli-fies the interconnection between a digital mixingconsole and a digital multichannel tape recorder;originally it was in fact designed as a point-to-point connection between devices of this kind.In addition it would be very attractive if we couldcombine all outputs of a studio and send themvia one MADI cable to the main switching roomintead of having a multitude of single audio ca-bles. This, however, would require the techologyof «unpacking» the MADI frames and to «repack»the single audio channels into other MADIframes.

If this problem is solved it is then only a smallstep to a MADI router: there is merely the switchermissing which is able to route the single channelsout of a MADI packet.

3. The MADI RouterSTUDER has solved these problems and is offer-ing MADI-Router as a part of its system solutions.MADI-Router are already in operation in Franceand in Switzerland and work to the customers‘full satisfaction.

The system consists of:• peripheral components which have the abil-

ity to «pack» audio sources into MADI frames(Fig. 3 left hand side) or to distribute a MADIframe to the single audio destinations (Fig. 3right hand side),

• and a switching node (Fig. 3 center), whichreceives and sends MADI signals.

A MADI Router can be regarded as a networkwith a star topology. The hub (switching node)reaches with eight MADI channels a through-

Fig. 3: Block diagram ofthe MADI-Router

put of 1 Gigabit/s, which is among the fastestnetwork systems today. In contrary to pure com-puter networks MADI has the advantage thatAES/EBU signals can be directly processed with-out format conversions.

The peripheral components accept either AES3signals (via interface) or analog signals (via con-verter). In both cases the signals first are givenon an internal bus working in time multiplex(Fig. 5). This bus consequently then feeds theMADI driver.

It can happen that a studio does not supplyenough channels to fill a full MADI frame. Theperipheral components are able to accept par-tially filled MADI frames, to fill it up with theown input signals, and to resend it (Fig. 3 leftbottom). This process can be daisy-chained untilall subframes of a MADI signal are set valid (i. e.contain useful data).

Vice versa the system works also at the audiosinks (Fig. 3 right bottom).

Fig. 5 depicts the components for the conversionfor analog signals (a) and for AES/EBU-signals(b). The output of the A/D-converter in (a) feedsdirectly the internal multiplex bus, an additionalinsertion of the component (b) is not required.The components for the re-conversion are builtvice-versa.

The switching node has the duty to extract singlesubframes from a MADI signal and to insert itinto another MADI frame. This switching transi-tion has to happen exactly at the beginning ofa AES subframe. Any other switching point couldlead to incomplete AES frames, which then arenot readable or may produce switching clicks.

Fig. 4: Indication of the matrix status via video monitor

5

SWISS SOUND 36

DA

DS-D C4AD

AES

TMD-Bus

DS-D AESI

AES

TMD-BusAbb. 5a Abb. 5b

TRESORTM LANIRLIRLIRL

IRL

CONTROL UNIT

LEVEL 2LEVEL 1

LEVEL 3LEVEL4

V24

V24 V24 V24

CS-485

CONTROL PANEL

E/S BUS

RS485

MATRIX

IRL

CONTROL UNIT

LEVEL 2LEVEL 1

LEVEL 3LEVEL4

V24CS-485

CONTROL PANEL

E/S BUS

RS485

MATRIX

PC PC

CS-RANGE SCALE 3 BASIC APPLICATION

PC

These requirements call for a multitude of con-trol facilities on different hierarchy levels andlocations. Interconnetion of the control devicesvia LAN is a very versatile solution; if the controlunit is a PC it can talk directly to the network,in cases of dedicated control keyboards appro-priate interfaces are required (Fig. 6). To improvetransparency labels can be designated to thesingle sources or sinks.

The networked control is very reliable and canbe easily expanded. Control hierarchy is definedby programmes and can thus by adapted tochanging operational requirements. The matrixstatus can be indicated on different locationsby video data monitors (Fig. 4).The STUDER MADI-ROUTER provides high-

speed DSP capacity which allows the integrationof mixing tasks into the system like crossoverbetween two switching states or mono signalgeneration out of a stereo source.

In the AES3 standard a preamble infringes thecoding law and can thus be easily identified.Such a method is not provided in the MADI stand-ard. Whilst the AES3 signal is a «self clockingcode», the MADI signal requires an external syncsignal which has to clock not only the switchingnode but also the peripheral components. It isgood engineering practice to use the same syncsignal to distribute the master clock to the singlestudios thus solving two problems at the sametime.

A certain tolerance is allowed for the AES3 inputsor outputs connected at the peripheral compo-nents. If they are clocked with the same clockfrequency their phase may shift up to the toler-ances as defined in AES11. Such phase offsetscan easily occur by cable delay times. But if alsothe clock frequency is different from the MADIreference clock (e. g. in connection with exter-nal sources) asynchronous SFCs are required.

4. Control circuitsThe control of matrix routers has to be possiblein many different ways, e.g. by:

• automatic mode according to a switchingschedule and triggered by a real time clock,

• manual interference in case of short-termalternation, either by editing the switchingschedule or by direct control,

• full manual control in case of unexpectedand immediate changes.

Literature:

[1] MADI INTERFACE - AN OVERVIEWS. Plumbridge und Y. Hashmi, STUDIO SOUNDDezember 1989, p. 35-36

[2] AES RECOMMENDED PRACTICE FOR DIGITAL AUDIOENGINEERING - SERIAL MULTICHANNEL DIGITAL IN-TERFACE (MADI)Journal of the AES, Vol. 39, 1991, p. 368-377

Fig. 5: Converter elements for analog and digital signals

Fig. 6: Matrix control via LAN

6

SWISS SOUND 36

STUDER Service Seminars in 1996/1

96031E Service Course A807 english 11.03. - 14.03.96 4 daysTape deck features, ports disassembling/assembling and alignment of tape deck, explanation of various circuits, trouble-shooting.

96032E Training Course D424 english 18.03. - 20.03.96 3 daysMO-technology, operation, applications, explanation, servicing.

96033E Training Course D827 MCH english 21.03. - 22.03.96 2 daysOperation and applications.

96934E Service Course D827 MCH english 25.03. - 27.03.96 3 daysElectronics, trouble-shooting and servicing.

96951E Service Course D741 english 20.05. - 21.05.96 2 daysCD-R-technology in general, operation, explanation of circuits, disassembling/assembling, alignments and servicing.

96052E Service Course D730, D731, D731QC english 22.05. - 24.05.96 3 daysD732, C221

CD-technology in general, operation, explanation of circuits, disassembling/assembling, alignments and servicing.

96061E Service Course 980 english 24.06. - 27.06.96 4 daysElectronics, trouble-shooting and servicing.

We offer:

Symposia and SeminarsSymposia and SeminarsSymposia and SeminarsSymposia and SeminarsSymposia and Seminars

Symposium in digital ...

The rapid advance of proceeding technology isin many cases the main topic in discussions withour customers. Actual example: Hosted by theTraining Center of the Deutsche Welle (Germanfederal short wave station, Cologne) STUDERparticipated in a Symposium held in KualaLumpur (Malaysia); Robert Müller (right) spokeon «Digital Studio Engineering».

with Martin Berner (second from left) being theinstructor with longstanding expertise.

... and Service Seminar in analogue:

If all 1/4" tape recorders ever manufactured bySTUDER would be added up, one could counteasily more than 100.000 units. Many are stillin operation and work day and night.

To guarantee undisturbed operation, regularmaintenance is mandatory. This requires, how-ever, occasional information updates by our ex-perts who can share their experience.

Hence STUDER offers Service Courses for all dif-ferent units in regular time intervals. The interestof the customers can be seen by the participationfrom all over the world; Danmark, Switzerlandand Korea e. g. joined for a recent A807 seminar

(This List represents the actual situation. As changes are possible please check again prior to registration).

7

SWISS SOUND 36

We hear:

NeNeNeNeNews frws frws frws frws from our Reprom our Reprom our Reprom our Reprom our Representaesentaesentaesentaesentatititititivvvvveseseseses

NDR is using DYAXIS IIi in production

by Bernd Fuhrmann

STUDER Germany installed in August 1995 a24-channel DYAXIS IIi system in the drama pro-duction studio of the NDR (North German Radio)in Hamburg. In 1994 NDR used already a 16-channel DYAXIS II system for the production ofthe drama «The man who lived twice» (140 min-utes, director: Norbert Schaeffer) which waspromptly awarded the «drama of the month»citation by the academy of arts. So NDR’s re-cent decision to continue with the STUDEREdiTech product line was not a surprise.

NDR gave the task of planning and integrationof the existing analog technique environmentto STUDER Germany. In discussions with theNDR engineers and technicians the requirementscould be defined and possible solutions werediscussed.

The system is operated from the machine roomvia a MultiDesk and two Monitors. The controlroom has another VDU for monitoring purposes.To ensure sight contact and an undisturbed soundarea for the monitor speakers, the two videomonitors have been lowered down next to theMultiDesk and mounted on a rolling table whichwas individually designed for this application inclose cooperation with NDR‘s physician withspecial attention to the ergonomic aspects.

This world wide largest DYAXIS IIi installation usessix HD drives with a total capacity of 24 GByte(equivalent to 66 track hours). Two stand-bydrives are provided for operation use during theback-up phase of the system.

The complete system and additional devices likeD731, D19, D740 and digital patch bay aremounted in racks, painted - like the moveablecontrol table - in STUDER colours.

The drama department of the NDR in Hamburghas with this installation definitively performedthe step into the digital age; since the installationall drama productions have been made on theDYAXIS system.

Clear solutions inspite short timeframes

by Achim Strauch

MDR (Central German Radio) has to clear hisexisting studios in the state parliament by theend of this year. As the new buildings are yet ina very early state of planning, an intermediatesolution was necessary.

Two continuity studios (D.J. type) had to be con-structed plus the existing production studio trans-ferred to the intermediate premises. The new on-air studios are equipped with one STUDER 970console, three D731 CD Player, two A807 TapeRecorder, and one A721 Cassette Recorder each.The studios are prepared for the installation ofcomputer-aided transmission systems. STUDER

Germany supplied not only the equipment butalso the woodwork and the patch bays, and per-formed planning, installation and comissioningon site.

The existing production studio was moved to thenew venue, installed and put into operation.The heart of this area is a STUDER 903 produc-tion console.

A new intercom system developed by STUDERGermany has been installed in all studios. Thecommunication between studio CEO, moderatorand control room is achieved in a very comfort-

8

SWISS SOUND 36

NeNeNeNeNews frws frws frws frws from the STUDER wom the STUDER wom the STUDER wom the STUDER wom the STUDER worororororldldldldld

• From the United States we received an ordercovering 60 STUDER A827 Multitrack TapeRecorders; 11 units alone go the the New Yorkbased studio Hit Factory which replaces partof its multitrack recorder pool.

• KBS in Seoul ordered 16 STUDER 963 mixingconsoles; the delivery must be completedalready by January 1997.

• EPLS in Algeria has substantual plans of ex-panding their facilities and has purchased60 STUDER A807, 30 STUDER D731 and anumber of STUDER Mixing Consoles.

• The Sendezentrum München (TransmissionCenter) took delivery of the largest STUDER990 built so far; this digitally controlledanalog console features 60 input channels.For audio post production in the TV depart-ment 4 STUDER 962 mixing consoles withVCA control and video editor control inter-face were ordered.

• Taiwan will receive three STUDER D827Digital Multitrack Recorders. In this countrywith highly developed studio structure thena total of six of these units will be in opera-tion.

• MBC Seoul purchased four STUDER 963mixing consoles which will go successivelyinto operation, the last in mid 1997.

• NDR in Hamburg is expanding; next to theDYAXIS IIi (see page 7) one STUDER 903mixing console and three STUDER D827Digital Multitrack Recorder with 24-bit ex-tension will go into operation.

• ERTU in Cairo has placed an order withSTUDER concerning the audio installationsin the TV studios 1 and 4.

able way (priority levels, call storage, busy indi-cation and integration in the existing consoles).The intercom system allows also monitoring ofdifferent program contributions based onSTUDER 990 technology.

The total work was performed in seven weeks.Since November 30 the studios are on air.

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SWISS SOUND 36

Rudolf Kiseljak

STUDER D19 MicVSTUDER D19 MicVSTUDER D19 MicVSTUDER D19 MicVSTUDER D19 MicVALALALALALVEVEVEVEVE

THE NEW PRODUCT IN THE STUDER D19 SERIES

by Rudolf Kiseljak

Basic designThe D19 MicVALVE is a 2-channel MIC/LINEpreamplifier with analogue and digital outputs.The basic signal path is solid-state, enabling su-perb direct to digital recordings.

A Valve Dignifier stage with 2 ECC 81 per channelcan be switched into the signal path, providinga number of controls for individual valve soundtreatment. Each channel has a switchable analoginsert and an analog output. Both channels arethen combined into an AES/EBU output. The builtin 20-bit A/D converter technology representstoday‘s state of the art. The mounting is modularand the A/D converter can easily be upgradedas technology advances.

The front panel of the unit is clearly laid out torepresent it‘s 2-channel nature. Each channel hascontrols for the Mic and the Line input sensitiv-ity and the Fine Gain of the selected input. Thelevel of the analog output can be adjsuted by aseparate knob. The Mic input features 48Vswitchable Phantom powering, a highpass filterand a phase reversal switch (which effects alsothe line input). Three more keys are used toswitch the valve stage into the signal path, selectthe insert point pre/post the valve stage and ac-tivate the insert, A bright LED display is used toindicate the activity of all those functions, as wellas for a 16-segment PPM meter.

The knobs for controlling the valve parametersare explained below.

A third operating area for global functions issituated at the right hand side. They include PeakHold of the PPM meters, a selection of internaland external sync clocks for the digital part, theanalog soft clip function and the output word-length selection. The 20-bit wordlength can be

Shortly after the introduction of the new STUDERD19 series of studio products in spring 1995 [1]the second unit from the range could be pre-sented at the 99. AES Convnetion in New York;it is named D19 MicVALVE and is, as the desig-nation already suggests, a mic preamplifierwith valves.

Together with the renaissance of natural soundsand the classical recorded performance of a realartist (as opposed to computer programmedsound) users quote often the term «valve sound»in a meaning far beyond nostalgic reminiscence.STUDER engineers have investigated systemati-cally the differences between valve and transisoramplifiers. The result of this research is now partof the D19 MicVALVE where the typical proper-ties of valve amplifiers are implemented in theform of adjustable parameters.

The unit is not just another «vintage» soundingpreamplifier with a valve stage, but more a de-vice like an equalizer with a variety of soundsto choose. A sound engineer can generate withthe help of this device his own acoustical picture.

At the same time, STUDER wanted to preservethe high resolution digital recording and process-ing with the advantage of good noise perform-ance, less distortion and the absence of crosstalkin focus. Therefore we are using one of the bestAnalogue to Digital converters on the market,included DSP Noise Shaping, and many otherinteresting features.

An initial order intake of 60 units at the exhibi-tion underlined that this concept found wideinterest on the market!

Fig. 1: D19 MicVALVEfront panel

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SWISS SOUND 36

Desination

Bass Warmth

Angel Zoom

Valve DriveSoft / Hard

Subjektive term

the sound of low frequencies becomesrounderbasses have more depthvocals have more bodypercussive instruments are less aggressive

adds transparency and clarity to vocalsemphasizes the solo instuments

tight, full soundthe sound is softer / harder

Technical reason

the group delay behaviour due to AC cou-pling of the stages is different in tube am-plifiers

valve amps have a characteristic response,midfrequency harmonic content is em-phasized

the harmonic spectrum when overloadedis different, the content of odd harmonicscan be adjusted.

Tab. 3: Properties of valve amplifiers

reduced to 16 bits, and either Dithering or NoiseShaping techniques [2] are used to retain mostof the 20-bit quality even on a 16-bit output.For the optional digital 8-channel output (either

ADATTM or TDIF-1TM, like in the D19 MicAD)the channel configuration of the AES/EBU out-put can be selected (fig. 1).

These parameters have been made adjustable inthe D 19 MicVALVE; the recording engineer isthus not forced to use a preset sound but has thepossibility to create a sound according to his indi-vidual likes.

The rear panel houses the separate XLR‘s for thetransformer balanced mic and line inputs, thetwo XLR pairs for the balanced analog inserts,and the line outputs. In addition to the analogconnections, there are the AES/EBU output andthe synchronization (supporting AES11) and word-clock inputs and outputs (fig.2).

Adjustment of the «valve sound»As stated above, Studer engineers have analyzedthe characteristics of the typical valve sound inorder to find out just which ingredients are re-sponsible. The differences from the theoreti-cally ideal amplifier transfer characteristics canbe described by 3 dominant parameters, bothin subjective and in technical terms (see table 3).

Literature:[1] D19 MicAD: Swiss Sound 35, page 2[2] Noise Shaper: Swiss Sound 35, page 3

Fig. 2: D19 MicVALVErear panel

Due to the variability of the single parametersand the excellent properties in the direct micro-phone path inclusive the A/D conversion theSTUDER D19 MicVALVE can be used in manyapplications in professional audio. Especiallyin direct digital recording, mastering, in projectstudios and in post production many tasks maybe successfully solved with this new develop-ment.

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SWISS SOUND 36

David Roth

Track n+1

Modulationstart detection

typ 100 ms

Track nnoise floor

(signal processingdelay of the CD - Recorder)

fixed threshold

Track n Track n+1

Modulationstart

100 ... 300 ms

variable threshold (preset)

-30 dB

-70 dB

noise floor

by David Roth

STUDER has been active in the research and de-velopment of CD Player and CD Recorder sys-tems for 12 years. With the CD Player generationD730, D731, D 731QC, D732 and the respec-tive remote systems STUDER offers a completeCD product range. The reliability, the capabilityto reproduce CDs even when far out of specifi-cations, the ergonomic design, the audio qualityand the dedicated unique features for the pro-fessional user are the key factor for our successwith the new CD Player generation.

The corresponding CD Recorder, the newSTUDER D741, was presented for the first timeat the recent AES Convention in New York. Thenumerous new features as well as the universalapplications have been very well received byour customers.

InterfacesMain target for the development was a universaldevice which can be used for all CD applica-tions. Transcriptions e.g. from archive tapes canbe generated via the balanced analog inputs;their sensitivity can be changed in the CAL modeto +15 dBu or +1 dBu (for low level HiFi sources)via a setup menu. In the UNCAL mode the levelsfor the right and left channel can be set inde-pendently.

Both, SPDIF and AES/EBU signals can be used asdigital sources. A built-in digital asynchronous

NeNeNeNeNew CD-Recorw CD-Recorw CD-Recorw CD-Recorw CD-Recorder fder fder fder fder for unior unior unior unior univvvvversal useersal useersal useersal useersal use

STUDER D741

sampling rate converter accepts input signalswith a sampling rate between 32 and 50 kHz.Via the setup menu the digital output can be di-rectly linked with the digital input which allowsa daisy-chain connection of several D741 CDRecorders. In this configuration several CD-Rs canbe produced at the same time; the drive controlis effected via the parallel control interface.

So far CD Recorders on the market have beeneither pure audio recorders or pure SCSI datarecorders without audio circuits and control sys-tems. There is, however, a clear trend on the mar-ket, that the strict separation of CD-Audio andthe different CD-ROM-formats belongs to thepast. Therefore, the STUDER D741 CD Recorderfeatures a SCSI 2 interface which allows to writeall common CD formats including audio (audioworkstations) in double speed and to read outCD-Rs up to four times real time.

The protocol of this interface is identical withthe new Philips CDD 2000. This allows the useof practically all CD-writer software packagesavailable today.

TRACK- and INDEX incrementTrack and Index marks can be generated via thekeyboard or automatically. In case of a digitalsource the track marks (in case of a CD sourcealso index marks) are derived from the sourcesubcode via the user channel in the AES/EBUor SPDIF interface. The time delay between trackmark and audio start can be normally neglected;however, an adjustable delay can be used forthe compensation of time delays such as lateID marks on DAT-tapes.

With analog sources the track mark can bederived from the modulation start of the audiosignal. Both, the threshold level ( -70 … -30 dB)and the audio delay time ( -1 … 0 … +1 second)can be adjusted. This wide range ensures thatalso different noise floors in analog recordingscan be accepted, and that the start time is alwaysbetween 100 and 300 ms after the track change(Fig. 1.2). Specially with CD-Recorders of thefirst generation due to internal delays, the modu-lation start was before the beginning of the track.As a result problems occurred, if such tracks hadto be cued on a CD Player (Fig. 1.1). This delayis also recommended because not all playersFig. 1.2: Adjustable delay of modulation start as well as the modulation threshold of the D741

Fig. 1.1: Automatic track increments of first generation CD-recorders

12

SWISS SOUND 36

Recording pulsewith opt. power Po andP << Po (too low)

reading power ~ 0,5mW

reflected recording pulse R from write pulse Po and P << Po

Po

P << Po

RPo read

RP << Po read

sampling of the pit reflectivity with the reading power

RPo

RP << P0

time

HF

sign

al

0

HF

sign

al

0

HF

sign

al

0

time time

A1

-A2

Fig. 3: Write power calibration based on intermediate measurement

Abb. 2.1: P << P0 Abb. 2.2: P ~ P0 Abb. 2.3: P >> P0

A1 + A2ß = A1 - A2

ß = 0 … 0,08

on the market cue as precisely as a STUDERCD Player. In addition, many CD Players havea soft muting function, which might be up to50 ms. Too early start after the track changewould then be partially muted.

Track at once- anddisc at once-modeThe D741 allows to create a CD-Audio step bystep. This means, that part of the disc may bewritten and additional tracks can be added later.This procedure is called incremental writing,assemble mode or track at once mode. The trackat once mode allows to add tracks to the disc,until the table of contents (TOC) is written.Whenever a new track is added to the alreadyexisting recording, an overlap of the recordingsis generated. As a consequence, an uncorrectableE32-flag is unavoidable (see also Swiss Soundno. 34, October 1994). Since there must be si-lence between such tracks, an E32-flag will re-sult in a non audible interpolation. However, ifthese discs are used for the direct transfer to the

glass master for the CD-production, these E32-flags might result in an interruption of this proc-ess. Not all pressing plants can handle CD-Rs,written in the track at once mode yet. Therefore,we recommend to check, if your pressing plantcan accept such CD-Rs. To avoid possible prob-lems caused by the track at once mode, theD741 allows in addition to write CD-Rs in thedisc at once mode through the SCSI-interface.In this mode, the complete disc including thetable of contents is written in one single step.Therefore no uncorrectable E32- flags will begenerated.

Individual laser power calibra-tion for each CD-R (OPC)The sensitivity of the recording layer can differconsiderably between different brands of CD-Rsand may vary in the range of 4 to 8 mW opticalwriting power required. The optimum value is pre-recorded in the ATIP of a preformatted CD-Rand so the coarse value can be adjusted in theCD Recorder. This coarse value is, however, notprecise enough and can generate asymmetricalHF which in turn may generate problems whenread on an older CD Player model. The cause canbe found in tolerances of the laser wavelength (andthe dependence of the optimum laser power onthe wavelength) and in tolerances in the mediumitself. To improve the situation the STUDER D741CD Recorder writes test recordings with differentlaser power in an unused area (power calibrationarea PCA) of the CD-R. Then the different test re-cordings are analysed. If the write power P ismuch larger or lower than the optimal value P0

the HF signal is not symmetrical (Fig. 2).In the CD Recorder D741, the asymmetry ofthe HF-signal (without DC) is measured with ß.Since ß has to be within 0 and 0.08, the toler-ance for the asymmetry is between -4 % … 0 %for CD-Rs. This is much less compared to normalCDs, which might have asymmetry between-20 % … + 20 %.

Dynamic control of the laserpower during writingIn spite of the general calibration of a CD-R atthe beginning (OPC) the results during the re-cording can differ from the optimum for thefollowing reasons:

• variations of sensitivity in different areas ofthe disc,

• change of laser wavelength due to tempera-ture differences,

• mechanical imperfections like finger prints,uneveness, etc.

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SWISS SOUND 36

NOB OB-VNOB OB-VNOB OB-VNOB OB-VNOB OB-Van fan fan fan fan for multichannelor multichannelor multichannelor multichannelor multichannelTV rTV rTV rTV rTV recorecorecorecorecordingdingdingdingding

NOB 61 is the name of the flagship among theOB Vans of the Nederlandse Oemroep-produktieBedrijf (NOB) and is designed for large and com-plex TV productions. Up to 16 cameras can beconnected, and production in different formats(16:9, 4:3) is possible.

The audio mixing console selected was the newSTUDER 980 not only for reasons of quality andreliability but especially because of it‘s multi-channel recording facilities. The desk is able tooperate in six master channels with the respec-tive controls in every input channel (L, C, R,front/rear, SPREAD and DIVERGENCE). Thus theconsole is able to work in DOLBY SURROUNDproductions, as well in 3/2 film sound and dig-ital multichannel formats (384 kbit/s).

The 980 console contains a very elegant moni-tor unit which enables the sound engineer to lis-ten to original, coded and decoded signals. Thisfeature enables to monitor not only the consoleoutput but also the quality of the signal as re-ceived by the final listener.

Fader and switch control can be performed byautomation. The settings (Snap-shots) can be easilystored on a small magnetic card in the size of abank card; sound engineers can save on this per-sonal medium their individual parameters.

Therefore STUDER has introduced an addi-tional dynamic control of the laser power dur-ing the recording. As on a normal CD the re-flection on «land» (no pit) is highest (approx.73%). Is a pit written, the reflection drops atthis spot due to interferences and refraction ef-fects to approx. 25%. In the STUDER D741 thewrite process during the generation of a pit willbe interrupted for a very short time (200 ns).The recorder is switched to «read-mode» and thereflection is measured. If the reflection is too

high, the laser writing power will be increaseduntil the correct value of 25 % will be reached(Fig. 3).

These different background processes (individualand dynamic laser current alignment for eachCD-R) are among other reasons responsible forthe excellent record parameters of the STUDERD741 CD Recorder and for the extremely goodplayability of such recorded discs on standardCD Players.

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SWISS SOUND 36

Dr. h. c. Willi Studer

In memoriam

Eugen SpörEugen SpörEugen SpörEugen SpörEugen SpörrrrrriiiiiAugust 2, 1935 - October 10, 1995

The sun is descending over the lake of Hallwil.Far out Eugen Spörri has anchored his sailingboat to prepare it for the winter to come. Hemakes a note in his logbook: Boat cleaned. Nowind.

These were his last words, his last act in an inten-sive life. Born in 1935 he grows up as a singlechild in a family in Wettingen, Aargau. He finisheshis business educationwith the trade diploma.His talents show up al-ready in this early state:languages, interest ininternational trade con-nections and in techni-cal matters. He is gain-ing first experience atthe Bührle Oerlikongroup and at Contravesand spends some timeabroad in an export-orientated company inthe U.K. In 1959 he mar-ries Martha Zimmer-mann; three daughtersand finally six grandchildren are offspringsof the family.

Much earlier he joinsEMT Wilhelm Franz AGin Wettingen and inMay 1962 he starts withthe task to develop theinternational sales ofprofessional STUDER audio products. With ateam of three colleagues the first export successis the legendary C37. This is the starting pointof his career: professional audio. Immediatelyan immense expansion work begins.

In 1971 EMT Wettingen is transferred intoSTUDER FRANZ AG with Eugen Spörri as man-aging director. In 1974 the company becomes a100% STUDER daughter company and is re-named STUDER INTERNATIONAL AG. Next tothe management of this company he becomesinstrumental in the inauguration of an interna-tional distribution network with independent

representatives. Additionally STUDER-ownedcompanies in important market areas are set upwith his help: between 1972 and 1983 daughtercompanies are founded in Austria, France,Canada, USA, Hongkong, Japan and Singapore.Eugen Spörri has direct influence on the businessdevelopment of these companies; his abilitiesto establish good contacts and his sensibility forthe market requirements have a very good in-

fluence. Besides theexpansion of the pro-fessional product rangehe pushes these part-nerships with greatpersonal engagementand opens new mar-kets.

In addition to the gen-eration of an internalorganization also ex-tended business tripsoverseas become moreand more part of hisduties. His direct con-tacts to professionalclients like radio andtelevision organiza-tions, major recordingstudios, and the audioindustry do not onlycreate confidence, butalso help formulateprecise marketing datafor the future productdevelopment. Success

duly rewards the effort: with approximately 190employees in Switzerland and abroad he realizesa turnover of more than 100 Mio. swiss francsfor the professional STUDER product lines.

In connection with the steady expansion of thebusiness new challenges come up. One is thetechnology transfer for the manufacturing oftape recorders in India and China - at a timewhen only few recognize the market potentialof these countries in the far east.

His excellent relations to the industry producesresults when he is constructing a Joint Venture

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SWISS SOUND 36

REVOX AG - with the well-known restruct-uration - Eugen Spörri on April 1, 1991 is ap-pointed head of the newly formed strategy andtechnology department.

So far the facts. It is no secret that Eugen Spörri- and with him not only his closest colleagues -could not support any longer the way MOTORCOLUMBUS operated the business. As an experthe had now to deal with managers with littleknowledge in the studio market. His objectionswere massive, but his rich experience was notin demand any more! This stress situation led tohealth problems, and on December 31, 1992he left the company after more than 30 years ofloyal work.

I have always regarded Eugen Spörri as a manof faithfulness and responsibility who performedhis work with expertise and personal engage-ment. We have lost a great personality and adear friend.

Dr. h. c. Willi Studer

with the PHILIPS company for the mutual de-velopment and production of CD Players.Eugen Spörri and his colleagues also manage acooperation with the japanese MATSUSHITAcompany to open the STUDER product line forthe R-DAT recorder domain. Finally his goodcontacts and his practical cooperation are im-portant when harddisk recording is establishedas a new working area for STUDER and the ac-quisition of the US company EDITECH is themilestone for entering this new field of tech-nology.

At the time when I realize the necessity for asuccession in my position in STUDER-REVOXEugen Spörri is effectively engaged in findingpossible solutions. On April 1, 1990 the MOTORCOLUMBUS group is taking over, and EugenSpörri becomes a member of the board of direc-tors. He is responsible as an executive officerfor marketing and sales, especially for STUDERINTERNATIONAL and the affiliates abroad. Inconnection with the reorganisation into divisionsshortly later and the formation of STUDER