DSPXmini-HD Digital Audio Broadcast Processor Operational Manual Version 1.10 www.bwbroadcast.
Table Of Contents Warranty 3 Safety 4 Forward 6 Introduction to the DSPX mini-HD 7 DSPXmini-HD connections 8 DSPXmini-HD metering and status LEDs 9 Meters and status LEDs 9 Quickstart 10 An introduction to audio processing 11 Source material quality, lowpass filtering and output levels 12 The DSPXmini-HD and its processing structure 13 The DSPXmini-HD processing block diagram 14 The menu system 15 The menu structure
Warranty BW Broadcast warrants the mechanical and electronic components of this product to be free of defects in material and workmanship for a period of one (1) year from the original date of purchase, in accordance with the warranty regulations described below. If the product shows any defects within the specified warranty period that are not due to normal wear and tear and/or improper handling by the user, BW Broadcast shall, at its sole discretion, either repair or replace the product.
Safety Instructions CAUTION: To reduce the risk of electrical shock, do not remove the cover. No user serviceable parts inside. refer servicing to qualified personnel. WARNING: To reduce the risk of fire or electrical shock, do not expose this appliance to rain or moisture. This symbol, wherever it appears, alerts you to important operating and maintenance instructions in the accompanying literature. Read the manual.
Object and Liquid Entry: Care should be taken so that objects do not fall and liquids are not spilled into the enclosure through openings.
Forward Thank you for your purchase of the DSPXmini-HD digital audio broadcast processor. Over the last decade the staff at BW Broadcast have observed broadcast processors from afar with fascination and intrigue and shared a keen interest in digital audio processing. In January 2002 we decided on a whim that it was time to have a go at designing our own digital audio processor.
Introduction To The DSPXmini-HD The BW Broadcast DSPXmini-HD is a new generation of digital audio signal processor that can be used to process audio ready for digital broadcasting such as HD Radio, DAB or Internet streaming. Using the latest multiband DSP technology the DSPXmini-HD offers a versatile and powerful tool in creating a loud punchy on-air presence.
Connections Analogue inputs DSPXmini-HD Analogue OUTPUTS LOAD PRESET AES / EBU OUTPUT (A) (A) SYNC INPUT DONE DEL INS GO UP LOAD UP AES / EBU INPUT 3779 RS232 & TRIGGER PORT ENTER NEW PASSCODE ENTER PASSCODE INS LAN PORT DSPXmini INPUT PROCESS OUTPUT DSPXmini INPUT PROCESS OUTPUT STATUS LEDS EDIT AES/EBU REMOTE DONE DEL INS DONE DEL DSPXmini-HD FRONT AND REAR PANELS GND LIFT MY PRESET 3 NAME PRESET U2 U1=BASS FACE U2=ROUND FACE U3=CLASSICAL 3 SAVE PRESET U1=BASS FAC
DSPXmini-HD Metering The DSPXmini-HD metering is accesable at any time by pressing the middle soft key on the front panel. It shows instant IO meters as well as all processing metering. I/O metering The input meters show the level of the input audio. The meters are ‘hooked in’ to the DSP code after the input level selection and mode options. D PRESET FACE D FACE ICAL 3 PRESET ACE D FACE ICAL 3 PRESET U2 SET 3 The output meters represent the level in dB below full scale output.
Quick start 1. Install the processor into the rack. 2. Connect AC power to the unit and turn on the power. 3. Connect the analogue and / or digital audio inputs. 4. Select the analogue or digital input as the source of the processing with the 'INPUT SELECTION' parameter which can be found in the 'INPUT' menu. Apply audio and observe the input meters. For analogue inputs, adjust the 'INPUT’ menus 'INPUT LEVEL CONTROL' so that the input meters do not clip.
Introduction To Audio Processing Most audio processors use a combination of compression, limiting and clipping to 'funnel' the dynamic range down, reducing the peak to average ratio in each stage. A cascaded arrangement of compressor, limiter and clipper produces the best results. The first stage of processing usually operates in a slow manner, the processing getting progressively faster and more aggressive as the audio passes through the chain.
Source Material Quality The DSPXmini-HD has the ability to substantially improve the quality of your ON-AIR digital broadcast. However it can only work with what you provide it. The best performance will be obtained when the processor is fed with very clean source material.
The DSPXmini-HD And Its Processing Structure The DSPXmini-HD broadcast audio processor is intended to be used for processing audio prior to digital audio broadcast or streaming. Before we discuss the processing structure in full we would like to tell you a little about the final peak limiting stage of the DSPXmini-HD. It employs look-ahead limiting as opposed to clipping.
Block Diagram 14 DIGITAL ANALOG SRC A/D INPUT BASS PEAK MID1 LIM MID2 LIM HIGH LIM MID1 AGC MID2 AGC HIGH AGC LOW LIM LOW AGC BASS CLIP DSPXmini-HD PROCESSING BLOCK DIAGRAM HPF BPF BPF LPF MB LIM MB AGC adj LPF N -1 DELAY ATTACK RELEASE LOOKAHEAD OUTPUT D/A SRC ANALOG SYNC DIGITAL
Menu System Overview This section presents an overview of the four main menus and thier submenus and any parameters that are contained in them. INPUT: Contains all the controls that affect input selection, level control and signal conditioning. PROCESS: Contains all the controls that affect the processing. OUTPUT: Contains all the controls that affect output selection, level control and signal conditioning. SCHEDULE: Contains all the real time clock controls for switching presets (Dayparting).
Menu Structure menu: input INPUT SOURCE ANALOG LEVEL menu: PROCESS menu: enhance peaking bass GAIN peaking bass FREQ peaking bass Q menu: MULTI-BAND AGC menuS: BANDS 1-4 DRIVE ATTACK DECAY GATE menu: MULTI-BAND LIMITERS MASTER LIMITER DRIVE menuS: BANDS 1-4 DRIVE LIMITER ATTACK LIMItER DECAY COMPRESSOR ATTACK COMPRESSOR DECAY menu: MIXER BAND 1 MIX level BAND 2 MIX level BAND 3 MIX level BAND 4 MIX level menu: LOOK-AHEAD BASS CLIP LEVEL
Processing Parameters The 'INPUT' menu contains options relating to the control and conditioning of the audio inputs. 'SOURCE' This parameter allows you to select the between the analog and digital inputs as the source for the processing. 'ANALOGUE INPUT A/D CLIP LEVEL' This parameter is only active on units with a serial number of 500 or greater. For serial numbers less that 500 see 'DSPXmini-HD Jumper Settings'.
'AVG ATTACK' Controls the average attack rate of the limiter. This control is a modifier control that scales from the peak attack control. The attack time can be varied between 1 and 10 which correspond to peak attack time / 2 to peak attack time / 1000 on a semi-exponential scale. The AVG attack control determines the dynamics of the dual time constant system and how control is shared between the peak and average circuits.
'LCD CONTRAST' Sets the contrast of the front panel LCD screen. The range is 0 to 25 'TRIGGER PORT' This enables or disables the rear panel trigger (remote) port. The options are enabled and disabled. More information is available in the trigger port section of this manual. 'CODE LOCK' This enables or disables the security code lock. The options are enabled and disabled. More information is available in the code lock section of this manual. 'OUTPUT LOCK' This enables or disables the output code lock.
Setting up the Processing on the DSPXmini-HD This section has more detailed information on setting up the DSPXmini-HD’s processing. Bass enhancement The frequency contouring effect of multi-band audio processors often leaves the bass lacking a little. The summation of the bands tends to give a boost to the presence frequencies and leaves the bass sounding a little thin. This effect can be compensated somewhat by enhancing the bass prior to multi-band processing.
Like most competent audio processors the AGC stages in the DSPXmini-HD are gated. This slows down the release time of the multi-band AGC when the program material drops below a certain level. This prevents noise suck up and gain hunting from occurring during quiet periods or lulls in the audio. The DSPXmini-HD allows adjusting the gate level over a range of -20dB to -40dB. This is the level at which the program material must fall below for the gate to become active.
mum setting of a balance of the two. The peak attack time should be set to the desired attack time required from that limiter. The range is 1-10 which corresponds to 1 to 200mS on an exponential scale. The peak decay time should be set to the desired peak decay time required for transients. The range is 1-10 which corresponds to a decay time of 10 to 1000mS.
Great care is needed in setting the drive control. This control needs to be adjusted carefully and only you can make the decision on the balance between loudness and quality. As you increase the drive you will obviously obtain more loudness but at the expense of distortion and "busy" sound. There is a fine line between artistic distortion and distortion that your listeners will find uncomfortable to listen to, especially for extended periods of time.
Getting The Sound You Want While the DSPXmini-HD can help you obtain the sound that you want we must always take into account the limitations presented to us by the transmission channel. The biggest problem we have is the maximum peak level that can be handled by that transmission channel, and for digital broadcasting services that is 0 dBfs. The trade off in any audio processor is loudness vs. quality.
Decrease the look-ahead limiter drive. WE SUGGEST ONLY SMALL MODIFICATIONS FROM FACTORY PRESET SETTINGS IF YOU ARE MODYFYING LOTS OF THE PARAMETERS. IF YOU ARE ADJUSTING ONLY A COUPLE FROM THE ABOVE SUGGESTIONS THEN YOU PROBABLY HAVE A BIT MORE LEE-WAY. IT IS VERY EASY TO LOSE YOUR WAY ONCE YOU START 'TWEAKING' LOTS OF DIFFERENT SETTINGS. More BASS We can obtain more bass in several ways Bass Enhancement: Increase the peaking filters gain.
Managing Presets (front panel control) The DSPXmini-HD has an assortment of factory presets and provision for 8 user ones. While the factory presets may not suit your tastes you will generally find one that serves as a good starting point in creating your own custom preset. The preset facilities of the DSPXmini-HD are accessed from the three intuitive soft keys. Selecting a preset.
Factory Presets The factory presets in the DSPXmini-HD are not supposed to be de facto standards by any means but are starting points for you to create your own user presets. It is impossible to create presets that will suit every format and market. What is right for one market is not usually right for another. The staff at BW Broadcast will be able to help you refine your sound further if none of the factory presets meet your requirement. The factory presets in v1.
Remote Control Of The DSPXmini-HD In addition to the front panel LCD control system the DSPXmini-HD has a serial port and an ethernet/LAN port. These allow remote control of the DSPXmini-HD through a remote application program running on a windows based PC. The remote control program is available for download from www.bwbroadcast.
Remote application connection screen NET/LAN PORT The DSPXmini-HD is equipped with a NET/LAN port for ease of remote control, setup and monitoring. CONTROL OF THE DSPXmini-HD BY THE NET/LAN PORT If you wish to use the NET/LAN port to control the DSPXmini-HD follow the steps below 1. Connect a cat 5 cable to the RJ45 port on the DSPXmini-HD and plug this into your network hub/switch. A Xover cable can be used to connect directly to a PC if you don’t have a switch or hub. 2. .
Remote application connected When the DSPXmini-HD is connected the LED’s will show activity and the main controls window should show processing controls, depending on what option is selected on the menu tree located to the left of the screen. The DSPXmini-HD remote control application has three windows. The left hand contains the navigation/preset window.
Preset window shown If you are not using dayparting or the external trigger port the default preset will always be the 'on air' preset and it will be marked in the preset list with a (DEF) which appends to the preset name. If the scheduler (dayparting) or the remote trigger interface has changed the preset the (DEF) marked preset may not be the one that is on the air. There are two additional identifiers to mark these occurrences. (DP) for Daypart and (TR) for remote trigger.
Loading presets from a PC This option will pop up the standard windows load dialog box. You can browse to and select a preset file to be loaded into the DSPXmini-HD. The preset location that is loaded is the currently highlighted (in blue) preset, not the one that is currently 'on-air' You can only load into a user preset. Preset icons SCHEDULING WITH THE REMOTE APPLICATION Using the menu tree to change the processing is quite simple and really doesn't need a lot of explanation.
by clicking down on the arrows until you reach the off option. If off is currently selected you can click up to rotate through the user and factory presets. The middle box contains the time and day that the daypart will start at. To select day, hour or minute click on the appropriate part of the box before using the up and down arrows. The day part of the time also has an ALL option. This means that the daypart will occur on every day.
MITERS OUTPUT HO LD -2 -4 -6 -8 -10 -12 -14 -16 -18 -20 -22 -24 4 5 dB 6 L 0 -1 -2 -3 -4 -5 -6 -7 -8 -9 -10 -11 -12 -15 -18 REMOTE AES/EBU EDIT R DSPXtra INPUT PROCESS OUTPUT UP LOAD SAVE Remote Trigger Port The system menu contains the remote trigger port option from where it can be enabled or disabled. If enabled the remote trigger port on the processor allows you to select any of the first 8 user presets by pulling one of 8 pins on the trigger port socket low.
Security Code Locks The system menu contains the security code lock options from where they can be enabled or disabled. The DSPXmini-HD has two code locks, the main full lock and the output lock. When enabled the full code lock prevents editing of the DSPXmini-HD parameters. When enabled the output lock restricts access to the output menu section of the DSPXmini-HD.
Clock Based Control (Dayparting) Your processor contains a battery backed up real time clock that can maintain the current time and date even when the power has been removed. This allows users to switch between presets at specific times of the day or week. This is very useful on a multi-format radio station where one processing preset may not suit all of the formats of music that are broadcast.
Specifications Frequency Response (Bypass Mode): ±0.10 dB, 2.0 Hz - 20 kHz or as set with the low pass filter. Noise: Output noise floor will depend upon on the processor settings but is governed by the dynamic range of the A/D Converter. The dynamic range of the digital signal processing is 144 dB. Processing Sample Rate: 48 kHz - 768 kHz depending on processing stage. Processing Resolution: Internal processing has 24 bit (fixed point) or higher resolution. Analog Audio Input Configuration: Stereo.
Other Voltage: 100–240 VAC, 50–60 Hz, 35 VA. Connector: IEC. Detachable 3-wire power cord supplied. Grounding: Circuit ground is independent of chassis ground, and can be isolated or connected with a rear panel switch. Dimensions (W x H x D): 44mm x 482mm x 200mm.
DSPXmini-HD v1.
LP FILTER DRIVE OUTPUT kHz dB kHz dB LEVEL Preset Sheet 40 kHz dB kHz dB
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