Behringer SRC2496 Manuel D’Utilisation

ULTRAMATCH PRO SRC2496

3. APPLICATIONS

3.2 Sample rate conversion

No matter which type of digital audio signal you feed into the

ULTRAMATCH PRO, it will convert it to a common standard format.

Numerous conversion examples can be found in daily studio

practice:
s

Conversion of 48 kHz DAT recordings to the CD standard of

44.1 kHz.

Conversion of older digital recordings from 44.056 kHz to

32, 44.1, 48, 88.2 or 96 kHz.

Conversion of foreign material with 32 kHz to 44.1, 48,

88.2 or 96 kHz.

Conversion of audio data with a word length of 24 bits to 20

or 16 bits for recording on a digital medium.

Conversion of S/PDIF format to AES/EBU for easy mani-

pulation of various parameters and improved (balanced)

signal transmission.

Setting or removing copy protect bits for further processing

of recordings in a studio environment.

3.2.1 Typical studio application with DAT

Only recently has it become possible to use less expensive DAT

recorders for direct recording from analog sources with a sampling

rate of 44.1 kHz. Most consumer-level DAT recorders, however,

record at 48 kHz. Usually, such recordings have to be transferred

via an analog connection from DAT to a professional recorder.

This process results in an unnecessary deterioration of the original

quality of the material due to the additional D/A and A/D converters

involved. With the ULTRAMATCH PRO you can eliminate this

problem by converting the sampling rate purely in the digital

domain, which allows for a considerably higher quality than you

could achieve with analog converters.

Further problems, such as incorrect formats, significantly deviating

or unstable sampling rates (as long as they do not deviate by more

than ±12.5% from the current sampling rate), will also be corrected

by the ULTRAMATCH PRO in real time, thus ensuring the

successful transfer of your audio data.

3.2.2 Hard-disk recording

Hard-disk recording applications also require a uniform sampling

rate, if possible the one used by the subsequent playback medium

(CD). As it can convert audio material from 32, 48, 88.2 or 96 kHz

to the standard 44.1 kHz, the ULTRAMATCH PRO makes sure

that any sources can be used to feed audio material by way of a

digital connection.

Of course, the ULTRAMATCH PRO can be inserted at any point

in the audio processing path, i.e. also between the PC and

DAT recorder. With uncritical audio material, you can thus process

the material at 32 kHz in the recording system (or higher, depending

on which sampling rates can be processed by the HD recording

system), and subsequently convert the completely edited material

while transferring it to a DAT recorder at 44.1 kHz (or even 48 kHz).

3.2.3 Master/slave problem solver

When a digital mixing console is used, it is at this pointif not

beforethat master/slave problems will be encountered. The

explanation is simple: When using CD players, DAT recorder and

HD recording systems in their normal applications, the

responsibilities are clearly defined. The playback device is the

master, the recording device is the slave, i.e. the CD player

provides a clock rate of 44.1 kHz to which the DAT recorder is

synchronized.

When using a mixing console, the CD player is the master, the

console is the slave. However, this model collapses all of a sudden

as soon as a DAT recorder is hooked up, which does not record

but plays back too. The console can synchronize to one source

only, the audio data from the other source would be processed

incorrectly, because the two devices are not in sync.

The need for synchronization in a digital studio is met by

connecting the equipment to one central sync source. For example,

the console could be the master supplying the remaining devices

with a reference signal (wordclock). However, this will only work if

these other devices have a sync input, i.e. can be used as slaves.

In a studio with a digital tape machine, digital effects and hard-

disk recording system it is impossible to connect commercially

available CD players or DAT recorders to the mixing section of

the console, simply because they cannot be synchronized.

By inserting the BEHRINGER ULTRAMATCH PRO SRC2496

between the device to be synchronized and the mixing console input,

however, the SRC2496 can deliver the audio signal with the studio

clock rate entered via the external sync input (WORDCLOCK,

In this case, the ULTRAMATCH PRO works as a kind of intermediate

gear whose toothed transmission always ensures that there is an

appropriate gap in the gearwheel. It synchronizes the signal coming

from the devices to be synchronized, while converting to the desired

sampling rate in compliance with the wordclock signal.

In a studio with a central clock generator, it is therefore possible

to use the ULTRAMATCH PRO to connect any device to any other,

irrespective of any other options available.

Even if the central clock does not correspond exactly to

one of the sampling rates, the ULTRAMATCH PRO will

assign a corresponding marker to the output signal! This

marker depends on the automatically detected and

displayed sampling rate, which is important, because

DAT recorders usually refuse to enter record mode if

an incorrect sampling rate has been indicated.

3.2.4 Bridging unformatted passages

DAT recorders, in particular, produce tiny format gaps between

individual recorded passages on the tape when intermittent recordings

are made. Also when you transfer older recordings it can happen

that short passages with a different sampling rate than that of the

current recording remain stored on tape. In such a case, the

ULTRAMATCH PRO converts this host of single pieces of information

into a continuous data stream with a fixed sampling rate. Even if the

DAT recorder or any other digital source is stopped or switched off,

the ULTRAMATCH PRO will continue to generate a continuous signal

(depending on the digital signal, if synchronized to it).

3.3 Removing copy protect information

The original copy protect mechanism used in DAT recorders

was simple but effective: It was impossible to make digital

recordings from a CD. Later, a step-by-step mechanism was

introduced with SCMS, which allowed at least for one digital copy

from CD. The routine implemented in SCMS depends on the

generation (x

copy) and the origin (category) of the digital audio

material. In professional studio engineering a copy protect

mechanism does not make any sense, which is why there is none

defined in the AES/EBU standard.

Since many studios use inexpensive consumer devices for cost

reasons, copy protect and/or format incompatibility problems

(professional/consumer) are encountered frequently. The

SRC2496 can ignore all types of copy protect information and

generate a new, completely free marker that allows for multiple

copying. Thus, you can use your ULTRAMATCH PRO to copy

material from one consumer DAT to another. Further information

on this subject can be found in chapter 2.1.3, section

We want to point out again that the copyright of third

parties must not be infringeddespite the possibility of

removing the copy protect bit with the help of the

ULTRAMATCH PRO! This device was not developed to

produce unauthorized copies!

3.4 Noise reduction with emphasis

A very special feature is the option to influence the set emphasis

bit. Emphasis here means a noise reduction process with a treble