SoundPool SRC Sample Rate Converter - Malcolm Ramage

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SoundPool SRC Sample Rate Converter - Malcolm Ramage

Post by exxos » Fri Jan 05, 2018 6:41 pm

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The SoundPool SRC Sample Rate Converter: product information courtesy of SoundPool GmbH, Zaberfeld-Germany

The SRC converts ALL sampling rates to the standard digital audio frequencies of 48 kHz, 44.1 kHz and 32 kHz. The SRC can serve as the Master Clock in a digital recording studio, enabling perfectly synchronized digital recordings.

The SRC does away with the "out of sync-ness" which occurs when devices with slightly varying sample rates are used simultaneously. The SRC is made up mainly of a modern high-performance DSP chip for sample rate conversion. On-line frequency analysis and complex conversion algorithms produce an output signal that differs from the original input signal only in the sample rate and in the copy bit being set to "original".

The SRC features both optical and coaxial inputs and outputs allowing you to interconnect all digital audio equipment with an SPDIF interface. If you have a DAT recorder without a coaxial input for which you want to connect to a CD player to without an optical output, the SRC will solve the problem. Of course only one input can be used at the same time.

Please note: In special mode the optical in/outputs are reserved for the sync signal!

SPDIF and AES/EBU Format

The SPDIF and AES/EBU format mainly differ in the electrical details, the digital audiodata format is fully compatible.

Copy Bit Handling


If you want to copy DAT recordings digitally without the SCMS copy prohibit flag, the SRC will do the job. The SRC cancels the Serial Copy Management System's copy-prohibit function found in many consumer DAT recorders, allowing you to copy recordings digitally as often as you like. Please observe all applicable copyright laws.

The Operation Modes

On the rearside you will find four DIP switches to select the operation modes and samplerates.

Normal Mode and Special Mode

With DIP 3 you can select the normal or special mode. DIP 4 selects Emphasis on/off in normal mode or Master/Slave in special mode.

Code: Select all

				DIP 3	DIP 4
Normal Mode  Emphasis Off 	OFF	OFF
Normal Mode  Emphasis On  	OFF	ON
Special Mode  Master	    	ON	OFF
Special Mode  Slave	    	ON	ON

In normal mode the SRC runs on internal clock. In special mode the SRC can be synchronized externally (slave mode) or generate a sync signal (master mode). In special mode, the coaxial inputs and outputs are reserved for audio data, while the sync signal passes through the optical in/outputs.

Emphasis

Emphasis coded signals must be played back in emphasis mode. If your signal is emphasis coded (displayed by you DAT recorder or CD player) select the emphasis mode manually with DIP 3/4 as shown above.

Sample Rates

With DIP 1/2 you can select the destination sample rate:

Code: Select all

		DIP 1	DIP 2
No Destination	OFF	OFF
48 kHz		OFF	ON
32 kHz		ON	OFF
44.1 kHz	ON	ON
Display of Destination and Source Sample Rate

The SRC detects the sampling frequency and displays it with an LED at the rear. Additionally, the SRC displays the source sample rate's deviation.

1. row destination samplerate
2. row source samplerate +/- 4%
3. row source samplerate +/- 400 ppm (parts per million)

This results in the following values:

4% 400ppm
32 kHz 30720 - 33280 31987 - 32012
44.1 kHz 42336 - 45869 44082 - 44117
48 kHz 46080 - 49920 47981 - 48019


Error LED

Errors may occur during the digital storage and transmission of audio data. CD players and DAT recorders can correct these errors within a certain range by detecting damaged parts and interpolating the missing data. For professional use this display is neccessary in order to control the quality of the employed data storage device. A LED at the rear shows the error status of the SPDIF source signal.

Attention: The LED will flash if the CD player or DAT recorder is set to PAUSE or Wind/Rewind. This is not an error indication.

The SRC as Converter

If your DAT recorder samples only in 48 kHz and 32 kHz (longplay), the SRC will convert these recordings into the 44.1 kHz format necessary for CD mastering and premastering.

Master Clock for HD Recording System

The SRC can serve as the Master Clock in a digital recording studio, enabling perfectly synchronized digital recordings. The SRC does away with the "out of sync-ness" which occurs when devices with slightly varying sample rates are used simultaneously. If you are having sync problems with your hard disk recording setup, you will find the SRC to be the solution. All modern hard disk recording systems (LOGIC Audio, Cubase Audio, Audio Tracker, Audio Master) can sync to an external clock, in RECORD as well as in PLAY mode. All Audio data is always transmitted via the SRC with a unitary sample rate. If you want to use 32 kHz as the sampling frequency on your hard disk recording system so you have more recording time, it's possible with the SRC.

External Sync (Special Mode)

In special mode the SRC can be synchronized externally (slave mode) or generate a sync signal (master mode). In special mode, the coaxial inputs and outputs are reserved for audio data, while the sync signal passes through the optical in/outputs.

Slave Mode

The destination sample rate (32 KHz, 44.1 kHz or 48 kHz) must be preselected at the slave SRC in order to correctly set the status bits for the transmitted sample rate. If the master clock deviates too much from the selected destination sample rate the receiving device (DAT recorder) cannot interprete this signal. Synchronization can only be performed with identical sample rates.

Master Mode

In master mode the masterclock is transferred via the optical out and can be used to sync another SRC, for example.

Technical Details

Coaxial in and out: cinch, SPDIF format
Optical in and out: TORX/TOTX, SPDIF format
LED display: 10 LEDs for frequency and status display
Power supply: External 500 mA, 7.5 V DC The SRC requires a 7.5 V / 500 mA
Stereo phaseshift: 0 degrees
Dynamik range: 96 dB (20...20000 Hz)
THD Noise: < 94 dB (20...20000 Hz)
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