Behringer Ultramatch Pro SRC2496 User Manual

ULTRAMATCH PRO SRC2496 User Manual

application. Therefore, programmers continue to experiment with the most 

varied of algorithms, ending up, however, always having to make a compromise 

between computation efforts and sound quality.
By processing data in real time, the processor used in the BEHRINGER 

ULTRAMATCH PRO can process incredible amounts of data. 
The noise and interference floor is thus below -117 dBFS, and the 

distortion values, even with difficult input signals, are below -104 dBFS. 

The ULTRAMATCH PRO remains practically inaudible as such values are not 

normally achieved either by the A/D or the D/A converter, and certainly not by the 

CD as the final product.

In principle there are two standards, the most important electrical characteristics of 

which can be seen in tab. 4.1. 
AES/EBU is the professional, balanced connection via XLR connectors. 

This interface is based on two identical protocols published in November 1985 

(EBU Tech. 3250-E) by the European Broadcast Union and in December 1985 by 

the Audio Engineering Society (AES3-1985). Sony and Philips oriented themselves 

to this standard and developed a further interface with unbalanced signal routing 

and a few other major differences, predominantly related to the assignment 

of the channel status bits. This interface, named after the two companies and 

known as S/PDIF (Sony/Philips Digital Interface), uses either RCA connectors or 

optical connections with optical fiber cables. The procedure, standardized in IEC 

958, made a name for itself mainly due to efforts to introduce a copy protect 

technique. This standard also describes the revised AES/EBU interface, which was 

adapted to the S/PDIF format and named IEC 958 Type I (professional). The name 

of the S/PDIF interface is then IEC 958 Type II (consumer). Your ULTRAMATCH PRO 

uses the latest versions of each of the standards, AES/EBU (AES3), IEC 60958 and 

EIAJ CP-1201 (Japanese standard).

Connection

XLR

RCA/optical

Mode

Balanced

Unbalanced

Impedance

110 Ohms

75 Ohms

Level

0,2 V to 5 Vpp

0,2 V to 0,5 V pp

Clock accuracy

Not specified

I: ± 50 ppm II: 0,1%  
III: Variable pitch

Jitter

± 20 ns

Not specified

Tab. 4.1: Important data for AES and IEC 958 Type II specifications

Table 4.2 illustrates part of the structure of the professional format, as it would 

normally be used with AES/EBU connections.

0

1

2

3

4

5

6

7

0

P/C

Audio

Emphasis

Locked

Sampl. freq.

1

Channel mode

Use of user bits

2

Use of AUX bits

Sample length

Reserved

3

Reserved for description of multichannel recording

4

Audio ref.

Reserved

5

Reserved

Tab. 4.2: Markers in professional format (AES/EBU)

Table 4.3 presents the corresponding consumer-format data, as normally used 

with S/PDIF-connections.

0

1

2

3

4

5

6

7

0

P/C

Audio Copy

Emphasis

Mode

1

Category code

Gen. st.

2

Source number

Channel number

3

Sampling frequency

Clock acc.

Reserved

Tab. 4.3: Markers in consumer format IEC 958 Type II (S/PDIF)

The first bit already defines whether the following bits are to be understood as 

professional or consumer-format bits. As shown, the audio information can be 

found at the same position in the data stream, in principle making both formats 

compatible. There are, however, information blocks that differ in both norms. If a 

piece of equipment, such as a commercially available DAT recorder, has only one 

S/PDIF input, the equipment will usually understand that format only. It will thus 

usually stop when supplied with professional-format data. The reason is simple: 

as shown in the illustrations, processing a professionally-coded signal with 

equipment that can only understand consumer format can lead to malfunctions 

relating to the copy protect bit and the emphasis!
However, this point is not always readily evident, as is the case with plug-and-

socket connectors (e.g. 1/4" TRS connectors, mini-jacks and special adapters for 

Sub-D instead of XLR connectors). A lot of equipment has no stop function while 

other equipment can understand both formats despite having only one type 

of connector.
In all of these cases using the ULTRAMATCH PRO as the ultimate problem solver 

will soon pay off. Virtually, all common digital signals it receives at the input 

appear at the output with new, clean markers in the respective chosen format.

The ULTRAMATCH PRO’s digital input and output connections are short-circuit-

proof and transformer-balanced. This rules out any possibility of ground loops 

caused by additional ground connections, even when using the RCA connectors. 

Furthermore, the completely potential-free concept of the digital connectors 

allows for using adapters in order to, e.g. route the RCA connector signal to the 

XLR input of another piece of equipment.
Unlike digital connectors, analog connectors are not galvanically separated, 

but have a balanced design and are thus unproblematic in regard to 

ground loops.

In order to give your audio signals the best possible protection from 

electromagnetic interference, the ULTRAMATCH PRO has balanced XLR inputs and 

outputs. As previously described, the level at the analog inputs can be adjusted 

with the GAIN control. The outputs operate at studio level (+4 dBu). Please see 

the following illustrations for the pin assignment of the connectors.
Of course, it is also possible to send signals to the SRC2496 from unbalanced 

outputs (e.g. sound cards or mixing console outputs) in order to further process 

them in digitized form. Receiving analog signals (e.g. when using a high-end D/A 

converter between a CD-Player and amplifier) from the ULTRAMATCH PRO via 

unbalanced connectors (e.g. hi-fi amplifier or tape recorder) is not a problem, too.