Audio.TST departs from its usual format to bring you a report from the AES (Audio Engineering Society) convention in San Francisco and the European Union of Hearing Aid Acousticians (EUHA) Congress in Frankfurt, Germany, both held during this past week. We’ll resume with a regular issue next month.
Report from the 133rd AES Convention San Francisco
The 133rd AES Convention in San Francisco was a wonderful show, with new energy abounding. It was great to reconnect with many old friends and meet many more new ones, and even better to see clearly the impact that AP analyzers have had on the audio industry for 28 years.
28 years exactly, in fact. On October 26, 1984, Audio Precision was incorporated, and well wishers came by to congratulate Bruce Hofer for giving them the tools that have advanced audio test and measurement for nearly three decades. We heard stories about 20 year-old System Ones that are still serving the audio community, and we appreciate knowing how our products have helped so many people.
It was also fun to be in San Francisco as the Giants won their second World Series in three years. The city was a very happy place to be!
AP's Nathan Rede and co-founder Bruce Hofer
New Products Introduced
At AES we introduced our new APx582 8 x 2 audio analyzer, combining the high performance generator of the APx525 with the multichannel capabilities of the APx585, and support for the complete range of APx Digital Options. We also introduced APx500 v3.1 Measurement Software for use with all APx Analyzers, now supporting direct ASIO connections to PC audio interfaces and other enhancements detailed below.
Bruce Hofer and FAE Dan Foley discuss measurement techniques with an AES attendee
Product Design Track Sponsorship
AP was pleased to co-sponsor the Product Design Track along with our friends at THAT Corporation. AP Field Application Engineers Dan Foley and Jonathan Novick spoke to an attentive audience about low noise test and measurement techniques, how to avoid mistakes with grounding, when to use sine or multitone stimulus, and real-world perceptual measurements using PESQ.
Report from the 2013 EUHA Congress Frankfurt
For the first time, AP attended the European Union of Hearing Aid Acousticians (EUHA) Congress in Frankfurt, Germany. There we introduced a brand new AP audio analyzer designed specifically for the hearing instrument industry, the APx511. The response was overwhelmingly positive, as the APx511 brings for the first time AP's legendary quality to this thriving segment of the audio marketplace.
AP's Dave Schmoldt and Tom Williams demonstrate the new APx511 hearing instrument analyzer
Sound Advice: What's New in APx500 v3.1
The team at Audio Precision has been working hard to make sure that engineers working with audio have the best and most capable tools possible. We’ve been listening to what our customers have to say, and are proud to introduce the new APx500 v3.1 software. Sporting a host of requested features and improvements, APx500 v3.1 is designed to improve productivity, increase flexibility and streamline workflows both in the lab and on the factory floor.
Support for APx582
The new two-channel output eight-channel input APx582 is supported by APx3.1 software.
The APx582 audio analyzer combines eight channels of analog input and two channels of analog output plus support for all of the APx digital interfaces (AES/SPDIF, I2S, HDMI, Bluetooth, PDM).
This configuration closely matches the inputs and outputs of modern multichannel audio devices which tend to have a maximum of two analog inputs plus HDMI or other I/O for multichannel or encoded audio.
Because it uses the output stage of an APx525 with the AG52 option, the APx582 offers a wide selection of output impedances (20, 50, 75, 100, and 600 Ω), supports several measurements that the APx585 does not have (including DIM/TIM distortion tests), has a higher maximum output, and can generate the sharpest square waves in the industry.
At –108 dB (typical), APx582 system THD+N is better than an APx585, but not quite as low as an APx525 (typically –110 dB THD+N).
New ASIO Interface
ASIO (Audio Stream Input/Output) is a popular sound device protocol for Microsoft Windows that provides a high-quality low-latency connection to an internal sound card or external audio device (typically via USB or IEEE 1394 Firewire interface).
APx500 now supports ASIO input and output, mapping up to 16 inputs and outputs (2 inputs and outputs for the APx515) to third-party ASIO device drivers.
Developers and manufacturers of ASIO devices will find this the perfect solution for characterizing their ASIO hardware.
New DC Level Sweep measurement
Measure DC Level and Noise while sweeping generator DC voltage across a range.
PESQ Reference File
PESQ now allows you to select an alternative reference file on the analysis side. Previously, the reference file was the same as the generator file. This feature allows you to create a modified (EQ’d) reference file with the inverse response of the loudspeaker, for example. Since the speaker response will bend this back to (somewhat) flat, you are now allowed to choose the un-EQ’d file as the reference. The only difference in the user interface is the addition of a Reference file selector, with a Browser.
Phase mode changes in Continuous Sweep and Acoustic Response
In APx500 v 3.0, the Continuous Sweep Phase and Group Delay measurements included the device delay, whereas the Acoustic Response measurements did not. In version 3.1, Acoustic Response Phase and Group Delay now include any device delay, making the results identical to Continuous Sweep results.
In support of this change, a new phase mode has been introduced, and existing phase modes have been renamed. IMD Split signal.
For the IMD, IMD Frequency Sweep and IMD Level Sweep measurements, the ability to route Frequency 1 and Frequency 2 to separate channels (rather than summing them in the generator) has been added. This provides a method to test microphone distortion characteristics without the added distortion of the reference loudspeaker.
User-defined Tuning Mode
In the THD+N, Bandpass Level Sweep and Stepped Level Sweep measurements, you can now specify which notch tuning mode (Generator Frequency, Measured Frequency, or Fixed Frequency) to use.
External Source for SNR and DNR
Signal to Noise Ratio and Dynamic Range can now operate in External Source configuration. Special waveforms are provided to facilitate this operation.
Noise Generation has been added to the Signal Path Setup: Verify Connections, Noise, Noise (Quasi-Peak), Noise Recorder and Signal Analyzer measurements. Noise signals are available in four shapes:
Maximum Output (Burst) renamed
The Maximum Output (Burst) measurement has been renamed to Maximum Output (CEA-2006).
Sequence step for Switchers
A new sequence step has been added, enabling switcher setup changes within a sequence.
PDM Interface Enhancements
PDM Oversampling Ratios expanded
A wide range of PDM oversampling ratios (decimation and interpolation) are now supported.
PDM amplifier control codes supported
Control codes can be embedded in a PDM stream, and are typically used to configure a downstream PDM device. If the device is an amplifier, the code may request a mute or an unmute, or adjust the volume, or request that the device power down.
APx now supports embedding and transmitting user-defined 2-digit (hex) codes, and monitoring received codes.
PDM channel assignment enhancement
For stereo PDM signals, APx now allows you to specify which data edge (rising or falling) is associated with the left or right audio channel.
DSIO Interface Enhancements
DSIO 32-Bit capability
DSIO can now receive and transmit digital audio at a bit depth (word length) of up to 32 bits.
DSIO Transmitter External Clock
The DSIO transmitter master clock can now be set to External, enabling additional DSIO/DUT configurations.
Other Digital Interface Enhancements
This enhancement requires upgraded Bluetooth hardware, available in November of 2012. The APx500 v 3.1 Bluetooth implementation supports HSP 1.6 wideband speech, the mSBC codec, flexible SCO and eSCO management and 48 kS/s A2DP source functionality.
Multichannel WAV file support
APx500 can now save and open multichannel WAV files, with bit depths (word lengths) up to 32 bits.
Digital Sample Rates enhancements
The range of supported digital sampling rates has been expanded, for both audio files and for DIO and DSIO.
HDMI EDID enhancement
EDID 1.4 is now supported.
Attach Graph Cursors to Trace
With APx500 version 3.1, you can now attach graph cursors to a trace, displaying dynamic readouts of the X, Y and Δ values along the trace.
Expand/Collapse Navigator Tree
A convenient Expand All / Collapse feature has been added to the Sequencer/Navigator context menu.
Audible Monitor Gain
A menu offering a range of fixed gain settings has been added to the Audible Monitor.
As part of our commitment to quality and continuous improvement, the following bugs from previous versions of software have been fixed:
Test Results: AP News & Events
© 2012 Audio Precision, Inc.