March 10, 2010 What's the iPad missing as an audio device?
By
Rich Pell
With all of the hype lately over the Apple iPad, I've noticed that the device's audio capabilities (or lack thereof) aren't receiving a lot of attention. I guess this is understandable given the device's intended purpose as a generic gadget for reading e-books, watching videos, browsing the Web and the like, but I would have thought music playback/creation too might have been high on its list of features.
Apparently not. Now I wouldn't expect such a device to deliver high-quality speaker output, but there are other amenities that it's missing that would have boosted its potential as an audio device in the eyes of many:
Audio line output
Audio line input
USB port
SD card slot
> 16 GB base storage
Limited operating system
Some of these can be worked around and others will likely improve with later generations of the product. Still, it seems likely that the iPad won't be quickly replacing many dedicated - and physically smaller - audio players available on the market.
That said, while I'd have liked to see more audio capabilities in the announced product, it remains a device I'll consider buying as an e-book reader/web browser/media player - if I can get around my reservations over Apple's closed system.
February 24, 2010 Acoustic metamaterials: Solution for noisy neighbors?
By
Rich Pell
I've mentioned before about my predicament having to deal with a noisy neighbor in an adjoining apartment. So recent news by researchers in Hong Kong of economical latex panels that might silence - or at least significantly reduce - the sounds emanating from next door piqued my interest.
There's nothing new about acoustic panels and room treatments. But these new panels are designed to address exactly the sort of sounds that I often find myself subjected to at all hours of the day or night - bass frequencies, which are typically difficult to block due to their long wavelengths.
The panels consist of a latex membrane stretched over a 3-mm-thick plastic grid of 1-cm-wide squares, with a small, weighted plastic button in the middle of each square. When the panels are hit by sound waves the latex membrane and weighted buttons resonate at different frequencies that cancel out the sound waves.
The membranes are tuned based on the weight of the plastic buttons. And they can be stacked to enable cancelling over a range of frequencies. According to the researchers, five differently tuned membranes stacked together could be used to create a panel that has a sound transmission loss of about 20 dB over a 70 to 500-Hz frequency range.
If they're able to be manufactured economically, these panels - at about 15-mm thick and weighing about the same as bathroom tiles - certainly would seem to be a more practical solution to the problem of noisy neighbors than other alternatives I can think of off the top of my head:
Of course the easiest solution would be if noisy neighbors acted more considerately once made aware of the problem. In my case the results have been mixed so far.
I was reminded of this just a couple of weeks ago when I had to pay my next-door neighbor a 1 AM visit to ask him to turn down his entertainment system. He did, but apparently at great inconvenience. Those latex panels are looking better all the time.
February 10, 2010 Audio Myths Workshop video
By
Rich Pell
Here's a video version of the Audio Myths workshop that was held at the AES show in New York City last October. This wide-ranging presentation refutes a variety of audio myths found in both the consumer and professional audio fields, and covers such topics as the human perceptual system, "placebo tweaks," proper testing methods, examples of artifact audibility, and the only four audio parameters that matter, among other things.
For convenient reference I've listed the various topics (below) along with the times they occur in the video:
(If you have problems viewing the above video, it can be viewed at YouTube here.)
Starting Time/Topic:
0:00 - Introduction by Ethan Winer
1:06 - James "JJ" Johnston on the human perceptual system (auditory) and auditory testing
5:20 - Poppy Crum on how "we are programmed to hear speech and programmed to make expectations about what sounds should be"; includes example of "Stairway to Heaven" played backwards
9:40 - Ethan Winer on human auditory memory and a review of a variety of placebo tweaks like ac power cords, LP Demagnetizer, "Brilliant Pebbles," "Quantum Clip" etc.
Part 2: Ethan Winer video presentation
16:50 - Comb filtering and how it may be one explanation for many so-called sound differences reported by audiophiles from "placebo" tweaks
19:00 - Loudspeaker distortion and variations in bass response in most listening environments are much worse than those produced by electronic gear
20:15 - Specifications and anti-science bias by those who believe they don't matter
21:35 - The four audio parameters that define everything needed to assess high-quality audio reproduction (frequency response, distortion, noise, and time-based errors)
22:48 - Euphonic distortion
23:13 - Specs provide all that's needed to assess transparency as long as complete data is presented
24:09 - Masking Effect and artifact audibility
25:20 - Proper listening test methods
28:30 - The Stacking Myth
30:45 - Proper Terminology (the uselessness of subjective terms etc.)
Part 3 - Audio Examples (Ethan Winer)
32:00 - Artifact Audibility
34:30 - Dither
41:15 - Sound Cards
45:05 - Analog vs. Digital
45:50 - Bit Reduction
47:45 - Phase Shift
53:40 - The Null Test
January 27, 2010 Video interview with MP3 co-inventor
By
Rich Pell
I've been listening to a lot of MP3s recently (mostly ripped from 128-kbps Internet Radio streams) and have been suprised at just how good many of them sound. Sure, they may suffer when compared directly with the original lossless files, but certainly as a portable format MP3 - despite getting a bad rap from many audiophiles - is a vast improvement over something like the cassette tape.
Those latex panels are looking better all the time.
