Welcome to the “Portable Sound Blaster” group at Google.
I (Steve Gibson) created this open public forum so that we — anyone and everyone interested in following, observing and/or contributing to this loosely organized research — would have a place to post and share information, thoughts, ideas, suggestions, news, updates, photos, links, resources, results, and any and all material relating to the topic of portable (or fixed installation) high-power sound generation devices and technologies.
!! — IMPORTANT NOTICE & DISCLAIMER — !!
This group explores the design of powerful devices capable of generating DIRECTED ACOUSTIC ENERGY OF EXTREME LOUDNESS, similar to that created by powerful high-end commercial consumer home, auto, and theater sound systems. As with all such systems, improper or incautious use may result in the permanent reduction or loss of hearing in people or animals. CAUSING SUCH DAMAGE IS EXPRESSLY NOT THE INTENT OF THIS PROJECT. Any use of the theory, technology, and capabilities discussed herein is ENTIRELY the responsibility of the creator and/or user of any devices arising from these discussions. As with other similar commercially available devices, these are meant ONLY for the purpose of animal training at a distance and/or the discouragement of noise generated by environmental pests. NO HAZARDOUS USE IS IMPLIED, SUGGESTED OR ENCOURAGED AND ANY SUCH USE IS EXPRESSLY DISCOURAGED.
TO EVERYONE: PLEASE BE RESPONSIBLE AND CAREFUL with the technology discussed herein.
You really COULD hurt yourself, your friends or your pets. There is nothing exotic or proprietary here. All components are readily available off the shelf. But at least one aspect of our collective interest is in exploring the upper bounds of what can be practically designed and created. The result of such an exploration WILL NOT BE TOYS and any devices created using these technologies should incorporate child-proof lock-out technology to prevent any inadvertent use. We will be dealing with sound pressure levels in the range of 110 to 140 decibels, which is the sound pressure generated by a jet engine at 100 meters. Possible hearing damage can occur at sound pressures of 120 dB and the threshold of pain occurs around 130 dB. NO ONE HERE WOULD EVER WANT ANY PERSON OR ANIMAL TO BE HURT. No one has that intention or purpose. So please use the technology discussed within this group responsibly. Please.
For those who already don't know of “The Portable Dog Killer”...
In August of 2005, Leo Laporte and I began co-producing a weekly podcast called “Security Now!” as part of Leo's TWiT (This Week in Tech) network of podcasts. On May 13th, 2010, in commemoration of the 50th anniversary of the invention of the LASER (Light Amplification through Stimulated Emission of Radiation) I took that week's podcast in a different direction, sharing with Leo and our listeners an adventure from my youth when I was 16 years old. That podcast has become one of our listeners' all time favorites. If you are not familiar with it, allow me to strongly urge you to take 45 minutes to listen to this edited-down MP3 audio version in any of three sizes and audio quality bit rates:
http://media.GRC.com/TPDK-16kbps.mp3 ( 5.4 mb)
http://media.GRC.com/TPDK-32kbps.mp3 (10.8 mb)
http://media.GRC.com/TPDK-64kbps.mp3 (21.6 mb)
(Everyone here will likely have listened to this before participating, so it should be considered a required orientation for understanding and participating in this forum.)
Why the name “Portable Sound Blaster” ???
Two Reasons:
First: 40 years ago, when I was a 16 year old nerd, I thought that the designation “portable dog killer” (for something that was obviously not) was perfectly acceptable and obviously meant to be humorous. But 40 years later that name makes me feel uncomfortable and self conscious. And during that podcast you heard Leo feeling that he needed to reiterate that the “portable dog killer” was never designed to — and could/would not — ever kill anything. As I stated during the podcast, it was designed to startle animals for the purpose of their training.
Second: The 21st century reincarnation of that original device will be significantly more capable. Being microprocessor (ARM Cortex-M3 RISC) driven, it can sample, record, analyze, and duplicate any sounds that it hears, as well as generate arbitrarily complex sonic waveforms. So its potential applications will be much more wide ranging than its original, modest, 40 year old predecessor.
Why an online Internet group?
Demand, curiosity, interest and need. Immediately after the original “PDK” podcast was aired, listeners began asking for “plans” to build their own device, though no such plans existed.
From the feedback I have received following that original podcast and its 2010 holiday rebroadcast, it is clear that a great many people have trouble with continually barking dogs owned by uncaring, disrespectful and irresponsible neighbors who cannot be bothered to honor their neighborhood's right to enjoy peace and quiet. A great many people are truly losing sleep over this problem, babies are being awakened, property values are being damaged (several people reported that they have been unable to sell their homes due to a barking dog next door) and individual's rights are being ignored. Every time I talk about that podcast episode and describe the problem canine that set it all in motion, people invariably want such a solution for themselves. And at this moment, three close friends are experiencing long-term neighboring canine noise pollution problems. While many of the commercially available devices might work at close range in an attack-preventing self defense application, they have proven ineffective for longer range “backyard” training.
Note that I have NO IDEA whether or how well anything that arises from this research might turn out to work. I am pursuing this purely for my own needs. But in the interest of sharing what I know, design and create — especially if it might improve other people's lives — I'm glad to contribute the additional time required to publicize this experimentation.
In my case, I am not being bothered by dogs, but the outside patio of my otherwise quiet local Starbucks coffeehouse is treated to a daily “social hour” of amazingly loud squawking crows... annoy many people in addition to me. The crows generally pass through around 6am and convene, en mass, like a black plague in several nearby trees. I have watched other Starbucks patrons yelling up at the trees full of birds, screaming at them to shut up. But, if anything, that only seems to encourage the birds' obnoxious squawking. As with dogs, I absolutely wish these birds no ill at all, but there are a great many other trees in the area, so I would love to have the means to simply encourage them to choose a different location.
It has become obvious that in addition to curiosity and general interest, a surprising number of people are suffering varying severity of ongoing problems with animal noise. So a device that harmlessly discourages such troublesome behavior — if it turns out to be effective — through some gentle auditory negative feedback, seems like a worthwhile exploration and development pursuit.
The animal rights position:
When, nearly a year after the original “PDK” podcast, I mentioned that I was becoming interested in exploring the re-creation of a sonic animal deterrent of some kind, many listeners were quite excited by the idea of having a contemporary version of this device.
But one or two listeners felt that anything that was purposefully loud and “negative” in any way would be cruel to aim at a defenseless animal. Consequently, I was urged not to proceed with the resurrection of such a device. Since I am a dog and animal lover who grew up surrounded by dogs and cats, I sympathize with such sentiments. But the existence of this group demonstrates that I have chosen not to heed such urging. In defense of my choice to proceed, I point to the fact that, when used as intended, NO ANIMAL WOULD EVER BE HARMED IN ANY WAY. Dogs are often scolded, swatted, and choked by collars as a means of instructing them about their owner's our wishes. So it's true that a persistently unruly canine might no longer get its way and would soon be trained that barking at nothing all afternoon isn't acceptable social policy. And a large tree full of noisy crows might be induced to move their cacophonous discussion elsewhere. But training pets to behave in ways that we wish is nothing new, and an electronic dog whistle seems far more humane than an electronic shock collar or other more forceful physical preventive measure.
Goals, capabilities and cost:
It is my expectation that this exploration will provide a fertile research and development base from which an array of different device solutions will emerge.
For example, two of my friends have suggested that non-portable installations would make more sense for them. They both have attic vents looking down into their neighbor's backyards where unruly dogs are constantly barking — despite their multiple patient complaints to the dogs' owners. So for them, a higher powered solution operating exclusively at a supersonic frequency would be ideal. This makes their requirements entirely different from those I have for experimenting with relocating noisy birds from Starbucks' trees... given that avian hearing begins to fall off above 8000 cycles per second (8kHz). This is a low frequency that is generally quite audible to any humans who are not hearing impaired.
It is always possible to reduce the loudness of an over-designed and overly loud device. But it is not possible to obtain additional loudness beyond the design limits built into a system. So my initial focus and interest has been in exploring the upper bounds of what can be achieved with a battery operated portable acoustic workstation... without any regard for what such a system would cost. I am only building one of these as a purely experimental prototype and development platform, so I don't care what that one device costs. I want to determine how such a device might be capable of performing? From what distance could it shatter a glass once it has determined and locked onto the glass's natural resonant frequency?
So it is not my intention that anyone necessarily follows immediately, or ever, in my footsteps. The first device I will be building is intended to host a flexible architecture and to serve as a platform for ongoing experiments. It will likely turn out that a much more economical “purpose built” solution would be capable of delivering nearly the same result at far less expense.
In any event, you are invited to join us and roam the various topics in this group, participating, commenting, contributing, and just hanging out.
This Google Docs page will be updated to contain the current findings, links, resources, and information about the project... in addition to the discussions occurring within the many other topics in this group:
Please see the "Primary General Discussion Area" topic, and all of the others, for additional information, discussion, and information.
Welcome!
