DSPXmini-FM SE
Broadcast Audio Processor
Operational Manual
Version 2.20
www.bwbroadcast.com
Table Of Contents
Warranty |
3 |
Safety |
4 |
Forward |
6 |
Introduction to the DSPXmini-FM SE |
7 |
DSPXmini-FM SE connections |
8 |
DSPXmini-FM SE metering and status LEDs |
9 |
Quickstart |
10 |
An introduction to audio processing |
11 |
Source material quality and pre-emphasis |
12 |
The DSPXmini-FM SE and its processing structure |
13 |
Processing block diagram |
14 |
The DSPXmini-FM SE menu system |
15 |
The menu structure |
16 |
Processing Parameters |
17 |
Setting up the processing on the DSPXmini-FM SE |
20 |
Getting the sound that you want |
24 |
Managing Presets |
26 |
Remote control of the DSPXmini-FM SE |
27 |
Remote trigger port |
33 |
Security code lock |
34 |
Clock based control |
35 |
Specifications |
36 |
Preset sheet |
Appendix A |
Table Of Contents
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.
If the warranty claim proves to be justified, the product will be returned to the user freight prepaid. Warranty claims other than those indicated above are expressly excluded.
Return authorisation number
To obtain warranty service, the buyer (or his authorized dealer) must call BW Broadcast during normal business hours BEFORE returning the product. All inquiries must be accompanied by a description of the problem. BW Broadcast will then issue a return authorization number.
Subsequently, the product must be returned in its original shipping carton, together with the return authorization number to the address indicated by BW Broadcast. Shipments without freight prepaid will not be accepted.
Warranty regulations
Warranty services will be furnished only if the product is accompanied by a copy of the original retail dealer’s invoice. Any product deemed eligible for repair or replacement by BW Broadcast under the terms of this warranty will be repaired or replaced within 30 days of receipt of the product at BW Broadcast.
If the product needs to be modified or adapted in order to comply with applicable technical or safety standards on a national or local level, in any country which is not the country for which the product was originally developed and manufactured, this modification/adaptation shall not be considered a defect in materials or workmanship. The warranty does not cover any such modification/adaptation, irrespective of whether it was carried out properly or not. Under the terms of this warranty, BW Broadcast shall not be held responsible for any cost resulting from such a modification/adaptation.
Free inspections and maintenance/repair work are expressly excluded from this warranty, in particular, if caused by improper handling of the product by the user. This also applies to defects caused by normal wear and tear, in particular, of faders, potentiometers, keys/buttons and similar parts.
Damages/defects caused by the following conditions are not covered by this warranty:
Misuse, neglect or failure to operate the unit in compliance with the instructions given in BW Broadcast user or service manuals.
Connection or operation of the unit in any way that does not comply with the technical or safety regulations applicable in the country where the product is used.
Damages/defects caused by force majeure or any other condition that is beyond the control of BW Broadcast.
Any repair or opening of the unit carried out by unauthorized personnel (user included) will void the warranty.
If an inspection of the product by BW Broadcast shows that the defect in question is not covered by the warranty, the inspection costs are payable by the customer.
Products which do not meet the terms of this warranty will be repaired exclusively at the buyer’s expense. BW Broadcast will inform the buyer of any such circumstance. If the buyer fails to submit a written repair order within 6 weeks after notification, BW Broadcast will return the unit C.O.D. with a separate invoice for freight and packing. Such costs will also be invoiced separately when the buyer has sent in a written repair order.
Warranty transferability
This warranty is extended exclusively to the original buyer (customer of retail dealer) and is not transferable to anyone who may subsequently purchase this product. No other person (retail dealer, etc.) shall be entitled to give any warranty promise on behalf of BW Broadcast.
Claims for damages
Failure of BW Broadcast to provide proper warranty service shall not entitle the buyer to claim (consequential) damages. In no event shall the liability of BW Broadcast exceed the invoiced value of the product.
Other warranty rights and national law
This warranty does not exclude or limit the buyer’s statutory rights provided by national law, in particular, any such rights against the seller that arise from a legally effective purchase contract. The warranty regulations mentioned herein are applicable unless they constitute an infringement of national warranty law.
Warranty
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 the presence of uninsulated dangerous voltage inside the enclosure—voltage that may be sufficient to constitute a risk of shock.
This symbol, wherever it appears, alerts you to important operating and maintenance instructions in the accompanying literature. Read the manual.
DETAILED SAFETY INSTRUCTIONS:
All the safety and operation instructions should be read before the appliance is operated.
Retain Instructions:
The safety and operating instructions should be retained for future reference.
Heed Warnings:
All warnings on the appliance and in the operating instructions should be adhered to.
Follow instructions:
All operation and user instructions should be followed.
Water and Moisture:
The appliance should not be used near water (e.g. near a bathtub, washbowl, kitchen sink, laundry tub, in a wet basement, or near a swimming pool etc.).
The appliance should not be exposed to dripping or splashing and objects filled with liquids should not be placed on the appliance.
Ventilation:
The appliance should be situated so that its location or position does not interfere with its proper ventilation. For example, the appliance should not be situated on a bed, sofa rug, or similar surface that may block the ventilation openings, or placed in a built-in installation, such as a bookcase or cabinet that may impede the flow of air through the ventilation openings.
Heat:
The appliance should be situated away from heat sources such as radiators, heat registers, stoves, or other appliance (including amplifiers) that produce heat.
Power Source:
The appliance should be connected to a power supply only of the type described in the operating instructions or as marked on the appliance.
Grounding or Polarization:
Precautions should be taken so that the grounding or polarization means of an appliance is not defeated.
Power-Cord Protection:
Power supply cords should be routed so that they are not likely to be walked on or pinched by items placed upon or against them, paying particular attention to cords and plugs, convenience receptacles and the point where they exit from the appliance.
Cleaning:
The appliance should be cleaned only as recommended by the manufacturer.
Non-use Periods:
The power cord of the appliance should be unplugged from the outlet when left unused for a long period of time.
Safety Instructions
Object and Liquid Entry:
Care should be taken so that objects do not fall and liquids are not spilled into the enclosure through openings.
Damage Requiring Service:
The appliance should be serviced by qualified service personnel when:
-The power supply cord or the plug has been damaged; or
-Objects have fallen, or liquid has been spilled into the appliance; or
-The appliance has been exposed to rain; or
-The appliance does not appear to operate normally or exhibits a marked change in performance; or
-The appliance has been dropped, or the enclosure damaged.
Servicing:
The user should not attempt to service the appliance beyond that is described in the Operating Instructions. All other servicing should be referred to qualified service personnel.
CE CONFORMANCE: This device complies with the requirements of the EEC Council Directives: 93/68/EEC (CE Marking); 73/23/EEC (Safety – low voltage directive); 2004/108/EC (electromagnetic compatibility). Conformity is declared to those standards: EN50081-1, EN50082-1.
WARNING: This equipment generates, uses, and can radiate radio frequency energy. If not installed and used in accordance with the instructions in this manual it may cause interference to radio communications. It has been tested and found to comply with the limits for a Class A computing device (pursuant to subpart J of Part 15 FCC Rules), designed to provide reasonable protection against such interference when operated in a commercial environment. Operation of this equipment in a residential area is likely to cause interference, at which case, the user, at his own expense, will be required to take whatever measures may be required to correct the interference.
CANADA WARNING: This digital apparatus does not exceed the Class A limits for radio noise emissions set out in the Radio Interference Regulations of the Canadian Department of Communications. Le present appareil numerique n'emet pas de bruits radioelectriques depassant les limits applicables aux brouillage radioelectrique edicte par le ministere des Communications de Canada.
Safety Instructions
Forward
Thank you for your purchase of the DSPXmini-FM SE digital audio broadcast processor.
The SE version in front of you is a successor of the very popular DSPXmini-FM. With a significant redesign of the limiter algorithm, crossovers, clippers and overall fine tuning, the DSPXmini SE provides smooth, clean and polished sound and at an extremely affordable price.
The original DSPXmini-FM was born as a scaled down version of the DSPX-FM with some reduced features like no LED metering, no analog and head phone outputs. It inherited the same 4-band processing structure, distor- tion-cancelled clipping and proven high-performance digital stereo generator. DSPXmini-FM then undergone significant overhaul to become the SE version. The DSPXmini-FM SE will offer stations on a budget, loudness, consistency and sound quality unmatched in a small processor like this.
Once again, thank you for your purchase; we hope you enjoy the DSPXmini-FM SE!
BW Broadcast Team
Forward
Introduction To The DSPXmini-FM SE
The BW Broadcast DSPXmini-FM SE is a new generation of digital audio signal processor that can be used to process audio for FM broadcasting. Using the latest multi-band DSP technology the DSPXmini-FM SE offers a versatile and powerful tool in creating a loud punchy on-air presence.
What's Under the Lid?
The DSPXmini-FM SE is driven by a fast 8 bit micro-controller which controls an array of specialised analogue and digital circuits. These include 24-bit A/D and D/A converters, analogue level control circuitry, 6 x 24 bit DSP's, an ethernet port, a trigger port, an RS232 port, an LCD screen and memory devices to hold the software and firmware.
The Processing Architecture
After input selection the 24-bit digital audio signal is passed through conditioning circuitry before being split to four bands by a phase matched crossover. Each band is processed by multiband RMS leveller which corrects for input level variations and also improves consistency. Each band is further processed by intelligent audio limiter. The following distortion cancelling clipping ensures your signal is kept to a strict maximum while maintaining clear sound. An oversampled DSP stereo encoder provides MPX generation with remarkable stereo separation.
The easy to use front panel control system with LCD afford the user with ease of use and setup.
Comprehensive control of every processing parameter is available to the user both from the front panel control system and by remote (computer) control.
At a fraction of the size, weight and price of its rivals, the DSPXmini-FM SE is small but serious FM processor.
Dynamic, fresh & innovative...
... The DSPXmini-FM SE
Introduction
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LOAD PRESET |
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ENTER PASSCODE |
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U1=BASS FACE |
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DEL |
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U2=ROUND FACE |
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U3=CLASSICAL 3 |
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LOAD |
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DONE |
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SAVE PRESET |
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ENTER NEW PASSCODE |
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DONE |
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NAME PRESET U2 |
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MY PRESET 3 |
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DONE |
DSPXmini |
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INPUT |
LOAD |
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PROCESS |
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OUTPUT |
SAVE |
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REMOTE
AES/EBU
D S P X m i n i - F M S E |
EDIT |
DSPXmini |
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INPUT |
LOAD |
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PROCESS |
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OUTPUT |
SAVE |
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STATUS |
CONTROL |
SOFT |
LEDS |
KNOB |
KEYS |
Connections
Analogue |
SCA |
MPX |
PILOT |
GND |
AES / EBU |
RS232 |
LAN |
MAINS POWER INPUT |
inputs |
INPUT |
OUTPUT |
OUTPUT |
LIFT |
INPUT |
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PORT |
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TRIGGER PORT |
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DSPXmini-FM SE FRONT AND REAR PANELS
DSPXmini-FM SE Metering
The DSPXmini-FM SE 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.
The output meters represent the level in dB below full scale output. This output level is the peak output level of the processing and has nothing to do with the actual output level set by the analogue and digital output level options.
The output meters show a smaller dynamic range compared to the input ones. This reflects the smaller dynamic range of the audio once processed by the DSPXmini-FM SE. If we were to have used the same scale as the input metering we would not see a lot of activity on the bars.
The multiplex output metering represents the composite outputs peak level. This is a representation of the output in relation to the peak composite level of the processing and not the actual level set by the multiplex output level control.
The IO meters follows an approximation of the PPM level of the audio waveform.
Multi-band AGC
The first four gain reduction meters show the gain reduction of the multi-band AGC. The range shown is -21dB to +21dB in 3dB steps.
There is only one meter per stereo channel and the value shown is the largest gain reduction of the left and right channels. Under normal operation (with a stereo audio feed) this is fine but you may observe strange metering if the channels are not very balanced in level.
Multi-band limiter
The second four gain reduction meters show the gain reduction of the multi-band limiter. The range shown is 0dB to -22.5dB in 1.5dB steps.
There is only one meter per stereo channel and the value shown is the largest gain reduction of the left and right channels. Under normal operation (with a stereo audio feed) this is fine but you may observe strange metering if the channels are not very balanced in level.
Status LEDS
The DSPXmini-FM SE front panel contains three status LEDS.
REMOTE: Indicates that the DSPXmini-FM SE is currently talking to a remote computer. This will flash dur- REMOTE ing an update of the firmware or remote control with the remote control application.
AES/EBU: Indicates the presence of a valid AES/EBU signal connected to the digital audio input of the |
AES/EBU |
DSPXmini-FM SE. |
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EDIT: Indicates that you are currently editing a parameter |
EDIT |
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Meters And Status LEDs
Quick start
1. Install the DSPXmini-FM SE into the rack.
2. Connect AC power to the unit, and turn on the power.
3. Connect the analogue or digital audio input.
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. Adjust input level as needed.
5. Select the pre-emphasis setting for your region (input menu). 75 µs for USA and 50 µs for Europe.
6. Navigate to the ‘STEREO’ menu and adjust the ‘MPX OUTPUT LEVEL’ to match the transmitter (or link device) that follows the DSPXmini-FM SE. Adjust for 100% modulation with audio.
7. Press the 'LOAD' soft key and select a preset from the list!
8. You're on the air!
Further information on each parameter is contained in the 'menu structure' and 'setting up the processing' sections of this manual.
Quick Start
10
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. The instantaneous peak clipper or look-ahead limiter is the final stage of the chain and sets the final peak level.
The images below illustrate a section of audio as it passes through a typical audio processor.
The first image to the right is an unprocessed section of audio.
The images that follow represent compression of the input waveform, followed by limiting and then finally peak clipping.
Compression
Compression reduces the dynamic range of the audio waveform slowly in a manner similar to a trained operator riding the gain. Compression is usually performed on the RMS level of the audio waveform and the ratio of compression is usually adjustable. Compression is usually gated to prevent gain riding and suck-up of noise during silence or quiet periods.
Limiting
Limiting is a faster form of compression that employs faster time constants and higher ratios to produce a denser sound while controlling peaks based upon the peak level of the audio waveform. Excessive limiting can create a busier packed wall of sound effect.
Clipping
Clipping the audio waveform will not produce any audible side effects if performed in moderation. Excessive clipping will produce a form of distortion that produces a tearing or ripping sound. Clipping can also be used as an effective method of high frequency peak control when used in conjunction with distortion controlling filtering.
Look-ahead limiting
Often used instead of a clipper in systems that feed bit rate reducing audio codecs, look-ahead limiting examines the audio waveform and prepares a gain control signal in advance of the delayed audio waveform arriving. This prevents overshoots while minimising distortion. A look-ahead limiter behaves in the same way as a soft clipper. Competent look-ahead limiters will usually be of the multi-band variety.
Introduction To Audio Processing
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Source Material Quality
The DSPXmini-FM SE has the ability to substantially improve the quality of your ON-AIR broadcast. However the DSPXmini-FM SE can only work with what you provide it. The best performance will be obtained when the DSPXmini-FM SE is fed with very clean source material. After dynamic multi-band re-equalisation is performed poor quality source material will sound poorer when processed with the DSPXmini-FM SE.
We strongly advise against the use of MP3's and other compressed audio formats for audio storage. If you must use compressed audio we advise rates of 256 Kbps and higher. Linear formats are always to be preferred. Compressed audio formats employ frequency masking data reduction techniques to reduce the bit-rate. Through re-equalisation the DSPXmini-FM SE can violate the frequency masking characteristics of the bit reduction process, creating distortion that was inaudible prior to the DSPXmini-FM SE processing.
Pre-emphasis
If you are using the DSPXmini-FM SE to process for FM broadcast you will need to enable the pre-emphasis filter in the DSPXmini-FM SE. Even though your STL or transmitter may contain pre-emphasis we recommend disabling it, letting the DSPXmini-FM SE handle the pre-emphasis for the transmission system. The DSPXminiFM SE uses sophisticated processing methods to limit the high frequency energy of the pre-emphasis curve while maintaining a 'bright' sound. Using de-emphasis and then pre-emphasising again will only degrade performance and possibly casue overshoots, resulting in lower average deviation.
The exception to the rule is when the DSPXmini-FM SE is feeding discrete left and right outs to a compressed audio STL. Bit rate reduction codec's do not cope with pre-emphasis very gracefully and artifacts will be generated. The best option in this case is to de-emphasise the output of the DSPXmini-FM SE prior to the STL system. At the transmitter site the pre-emphasis can be enabled in the transmitter to restore the processed signal back to normal prior to transmission.
The best solution is always to locate the processor at the transmission site. This way overshoots are minimised and quality is maintained.
Source Quality And Pre-emphasis
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