Audio Evidence And The History And
Evolution Of The Audio Recorder
By Ralph D. Thomas

One of my developed passions in life for some reason has always been audio tape recorders. As a kid, I collected them and played with them in my bedroom. I likely drove my parents nuts recording everything. When I grew up, I was lucky enough to become a private investigator and I used them in my work. In the last 30 years, I have marketed them through our company that specializes in retail and wholesale distribution of investigative gear. I have literally used and reviewed thousands of different types and models. In doing all that, one would have a natural want to go back before one's own time and research the history of the tape recorder as an investigative tool. The step beyond that, of course; is to start collecting all the tape recorders that have developed through the years. That is exactly what has been done and a lot of these older recorders are quite interesting. As a tape recorder addict, many of the newer models are wonders of the world to me. The old recorders I fine truly fascinating. You might not be the tape recorder addict that I am, but it's worth it to know a little about them. You can find both the old and the new on display in the Spy And Private-Eye Museum in Austin Texas which is now an extension of the Spy Exchange And Security Center. In going through the presentation below, on most of the recorders shown; you can click on the hotlink to get more information about that recorder. When you are in the Austin, Texas area, you might want to stop by the Spy Exchange And Security Center and go through our Spy and Private-Eye Museum so you can see this history in person. If you can not do that, go online to PI Vintage, The Spy And Private-Eye Museum.

Audio recorders and the ability to record one's voice have been around in one form or another since the early 1900's. However, you might not recognize the way in which voice was recorded from different decades starting in about 1910.

Wax Cylinder Recorders, 1910
In an attempt to improve telephone transmitter technology, Thomas Edison discovered that tape around the transmitter gave off a noise that resembled the spoken word. He worked on this and ended up developing both phonographs and what became known as the Dictophone, the really first voice recorder that recorded to a wax cylinder. These wax cylinders recorded for a total of an amazing two minutes.

Dictaphone Wax Recorder, 1910's
This is an early dictaphone that recorded to a wax cylinder. It was huge, heavy and bulky but this was state of the art stuff for it's time. The rounded shelving on the bottom of the stand was for storing either blank or already recorded wax cylinders. To "erase" a cylinder already used, you had a little peeling unit that simply shaved the wax off the outside of the unit. Eventually, the cylinder wasn't any good because too much wax had to be peeled off it. By all means, you wouldn't want to get these ah too hot as they might ah melt. Developed for business executives to sound out letters their secretaries would then type, there isn't much doubt about the wax recorder being used to audio record "evidence." Speaking of business executives recording their letters and memos for others to type, I have often wondered why all the time and expense was wasted on this instead of requiring business executives to learn how to type themselves. Of course, typing was a "skill" and also required spelling skills. You can click here to learn more about wax recorders.

The Detective Dictograph
, 1907
At about the same time that these wax cylinder recorders were being marketed, a fellow by the name of K. Monroe Turner invented a listening device which was a microphone that could be hidden with an amplifier and headphone. It came to be known as the Detective Dictograph.

Portable Detective Dictograph Audio Amplifier, 1907
The Portable Detective Dictograph Audio Amplifier from 1907 was made by General Acoustic Company, Jamaica, New York and invented by one K. Monroe Turner. This is one of the first audio amplifiers. Ads placed in law enforcement and private detective trade journals (of which there were very few at the time) claimed this this unit could be installed and hidden just about anywhere. You know, under "rugs" and "beds". This state-of-the-art equipment of it's time sold for about $125.00. Remember that the average salary in America at that time was about $750.00 a year. That means that this unit cost about two months pay. The units could be rented for about $6.00 a month. Several Congressman in Ohio and criminals in Los Angles quickly went to prison from the evidence the Detective Dictograph collected.

Wire Recorders, 1920s 1930s
The Detective Dictograph was a revolution for it's time period but it was a while before such equipment got hooked into what became known as audio recorders. No doubt, there were some tries at using a wax recorder to record sound from the detective dictograph but it just didn't work out very well. There was something out there and private-eyes and law enforcement soon found the device. It was called the wire recorder and it recorded voice to a wire instead of wax. The wire recorder was invented in 1898 by a Danish engineer by the name of Valdimar Poulsen and first called the Telegraphone. Poulsen's intention was to sell the wire as a telephone answering machine. It was technology that was way before it's time. Poulsen had problems marketing the device and had great difficulty explaining the practical use of the wire recorder. A few machines were manufactured under his name just after the turn of the century in Denmark. A decade later, the USA sold units reasonably as office dictation machines. It wasn't long until law enforcement and private-eyes found their machine.

The Webster Chicago Wire Recorder
Big, heavy and bulky, the first Webster Chicago Wire Recorders were a marvel to behold for their time. They would record audio and voice to a wire spool. Used in conjunction with the Detective Dictograph, private-eyes of the late 1930's had a dream come true. You could now covertly record voice through a hidden microphone and collect evidence in many ways. It took a lot to set these units up and you needed a lot of space to hide them. Private-investigators in those days made very good money covertly recording conversations of all kinds for evidence. But this equipment was huge.

RCA Wire Recorder, 1930's-1940's
This is a rare RCA Wire Recorder from the 1930's -early 1940s in a black bakelite case. The item to the right is the wire cartridge that would insert into the top slot. Like most wire recorders from this time period, you had to purchase the wire recording cartridges from the company that made the recorder. Nothing was standardized. This was a tube recorder. Note the knobs on the front of the recorder and the chrome grill. As you can see from the photo, this wire recorder is in like new condition. When this wire recorder first came out, it was hailed as a "portable wire machine" one could, ah....carry around if you didn't have a bad back. Note the handle on the top that pops up. Instead of reels of wire, this machine was easier and quicker to use since all you had to do was side the wire cartridge in it.

Sonoband Recorders, 1930's
Although audio recordings could now be done, prior setups was needed to hide these huge machines in closets and under beds. It wasn't until the Walkie Record-All of the mid 1930's came out that things got a little smaller and lighter.

Walkie-Recordall, -Circa 1930's, 1940's
The Walkie-Recordall was a portable audio recorder that recorded to a plastic type belt. The belt was called a Sonoband. The recorder measures 10.5 x 5 x 9 with the thing closed up. A needle etched the sound onto the Sonoband. The belt measures 16.5 x 1.75. The Walkie-Recorderall was developed as a dictation machine. The idea was that salesman and business people could carry the thing around and dictate memos which could later be typed up into business reports on typewriters. However, the Walkie Recordall never went over very well for that. However, because of it's portability and recording power, it was quickly adapted as a covert audio recorder by law enforcement and private investigators.

The Walkie-Recordall was highly popular in the 1930's and 1940's. It retailed for about $450.00. That was a lot of money then considering the fact that the average sold middle income paycheck was between $45.00 and $55.00 a week. That is over two months pay for a recorder. If you make about $700.00 a week today, this recorder would cost you about $5,600 by today's wage standards. This tyoe of equipment was really expensive in it's day. Although the thing measured 10.5 x 5 x 9 inches closed up, it was really small for it's time.

Portable Wire Recorders, 1940's
It wasn't long before state-of-the-art things changed again and recorders got smaller and lighter. A company in Germany released a small wire recorder in the 1940's and a revolution in small recording devices was started.

Minifon Portable Wire Recorder
The Minifon Portable Wire Recorder was state-of-the-art for it's time. It recorded to a wire spool much like the bulky Webster Chicago Wire Recorders did but this one was highly portable. Note that the case is steel and not plastic. Back in those days, things were made to last. The Minifon was released to be sold as a portable dictating machine that traveling salesman could carry with them. Like the Walkie-Recordall, it's use as a dictating machine did not develop in mass market. Instead, it become a popular product for note-taking by reporters, insurance adjusters, salesmen, private investigators, detectives and others. It also became a popular bugging device. The Minifon had a recording time of one hour which was very long for it's time. The basic machine cost around $289.00. Considering the fact that the average salary in 1940 was $1,299.00 a year, a Minifon cost over four month's salary. Based on today's income standards, it's cost in today's dollars would be around $12,000. If you had one, you had some very expensive equipment.

The Minifon developed with many accessories (see brochure) including "long play" wire cassettes that would record up to five hours, telephone recording attachments, foot control, watch microphone, table loudspeaker, deluxe leather carrying case, body harness and anything else the company could come up with.

For the covert recording private-eye, spy and law enforcement market, the most popular accessory for the Minifon was the watch microphone and the shoulder harness. Now, instead of pre-setup time to hide bulky recoding equipment under beds and in closets, these small units could be hidden almost anywhere even on one's own body. The Minifon was then the first real body recorder. The cord of the microphone stuck out the side of the watch and would run up one's arm to the hidden recorder.

The Fully Equipmented Minifon Investigator

Pictured to the right is an investigator wearing the Minifon with it's harness. The Minifon watch microphone is on his left arm. You can see the wire running up his arm. Although this would be rather crude by today's standards, this was highly revolutionary in the 1950s. The Minifon became the covert body audio recording system to have. It was sensational for it's time period and every governmental spy, private-eye and police department in the world wanted one. Those who could afford them got them. Made in Germany, the company had authorized Minifon dealers throughout the world and they were sold throughout the world.

Reel-To-Reel Magnetic Tape, 1940s, 1950s
Recording to wire was the only way to record audio unless you wanted to use Thomas Edison's wax method which was a real problem in heat and in long term storage ability. Wire spools had their own problems. The wire was really thin and could tangle very easily. In the 1930's Bell Telephone Laboratories had already invented a system of recording audio to magnetic tape but it was never really marketed. It was not until 1947 that reel-to-reel magnetic tapes started to be marketed in the United States. By this time there were a lot of different kinds of wire recorders on the market. One might think that there would be a compatibility problem but things were quite different in these days. In fact, whatever type of recorder you purchased, rather it be wax , wire or sonoband, you generally had to purchase the recording media from whatever company made the recorder. Things where just not standardized. One type of wire or brand would usually only work with the one brand product it was made for. Once you recorded something, the only way you could play it back was on the brand of recorder you recorded it on. This was done a great deal of time on purpose because the different companies making these recorders wanted you to purchase only their recording media and not someone else's. Reel-to-Reel magnetic type started to erode that somewhat when the tapes came out.

Magnetic tape reel-to-reel took off simply because it was much easier to use than wire spools. The companies that made wire recording equipment scrambled to convert the product they had to magnetic tape. Minifon soon released it's own reel-to-reel magnetic tape recorder which become quite successful. Those recorder makers who could not make the conversion from wire recorders to magnetic tape recorders quickly went out of business.

First Telephone Recorders, 1940s, 1950s
It wasn't long before someone dreamed up a way to record telephone conversations with some sort of mic. That was first done with what become known as an induction microphone. That is, a cord with a suction cup on the end of it. You would simply attach the suction devise to your telephone and the vibrations (which is what a microphone picks up anyway) would record both sides of a telephone call. Other innovations included running a secret wire from the telephone junction box to headphones or a microphone with a recorder in front of it that would then covertly record telephone conversations. In these days, there were no laws against wiretapping and there was no one and two party consent laws. Investigators were free to do whatever they could do. Wiretapping and tape recording flourished. The 1950's become the age of the small reel-to-reel magnetic tape recorder. Transistors came into being and tape reorders started to get even smaller. Mohawk Business machines released the first transistor tape recorder called the Midget!

The Mohawk Midget Recorder, 1950's

Prior to about 1950, tape recorders had been mostly big and bulky. With the exception of a few products like the Minifon most of the "portable" ones where about the size of a typewriter. They all used tubes. That all changed when the Mohawk Business Machines Company of New York released what they called The Midget Recorder around 1950.This was the first all transistor tape recorder. It was about 6" x 10" in size and used a small tape cartridge. Like many recorders of this time period, you had to purchase extra tape cartridges from the company that made the recorder. There were no standardized tape cartridges. The recorder was a modern revolution for it's time and very small! If you were a private investigator and had one of these back then, everyone in town marveled at at.

Minifon Recorders Got Smaller And Converted To Magnetic Tape

Cheaper Portable Reel-To-Reels, 1950's, 1960s
The problem with a lot of these high tech recorders where that they were expensive. They therefore had a limited market. Only the highly successful could afford them. If you had top of the line audio recording equipment, you had an investment that might be about the same as four to six months pay. It wasn't long before cheaper reel-to-reel recorders that worked well but didn't cost quite as much hit the USA market and private-investigators purchased them by the thousands.

Phono Trix Portable Reel Recorder Set with Carrying Case

Phono Trix Portable Reel Recorder Set is what a typical portable tape recorder was like in the 1950's. The measurements where 9" width, 7" depth, 5" height in the case. Very bulky by today's standards. Not only is the recorder bulky by today's standards for a portable, note how big the microphone is. You had to plug a speaker into this one for playback. As you can see, the speaker was kept out of the unit to make it as small as it could be made

PhonoTrix Miniature Tape Recorder, 1965
In the mid 1960's the miniature Phono Trix 88 recorder was introduced in the USA and become a popular alternative to the Minifon because of it's less expensive cost. It was only 1 7/8 inches X 4 1/4 inches X 7 1/2 inches and was billed an a new pocket-size recorder. I guess you had to have big pockets back then! It's weight was a mere 2 1/4 lbs. Like the Minifon, it was marketed through exclusive dealers and had a number of "fascinating" accessories including a tie clip mic, a pen mic, leather carrying case, stethoscope headphone, amplified speaker, shoulder holster and anything else the company could come up with.

The Electra Candid Covert Recorder 1960's
The Electra Candid Recorder model 770 was a small portable recorder for it's time. It came with a diamond (fake) incrusted tie tack pick-up mic.The name might have been developed from the TV program Candid Camera in which covert video was filmed and jokes played on people who were covertly filmed for the TV show. At the end of the joke, old Allen Funt would tell the subject, "Smile Your On Candid Camera."

Covert Diamond Tie-Clasp Mic, 1960's
This covert tie-clasp mic was sold with The Electra Candid Recorder model 770. Note the hole in the middle which is where the mic pickup is. The diamond, of course, it not real. This was quite a covert recording system for the 1960's.

Once the Covert Diamond Tie-Clasp Mic came on the market, it was quickly copied by other companies that made recording equipment and the market place as always soon flooded with different types of tie-clasp mics but none of them where quite as slick as the one pictured to the right.

Lloyds Miniature Recorder, Mission Impossible, 1960s
Although there were several recorders used on the TV program Mission Impossible, the most famous one is the Lloyds Miniature Recorder pictured above. At the start of each show, actor Peter Graves would obtain an envelope and a tape recorder that would contain details of his current assignment which was another "mission impossible" which only him and his team could do. The tape would self destruct after it was played.



Olympus Pencorder Reel-To-Reel 1960's
The Olympus Pencorder Reel-To-Reel was a really small recorder for it's time and this model was highly popular since Olympus was known for top quality. Despite it's name, it was certainly a whole lot bigger than a pen.

Reel-to-Reel tape recorders flourished in the 1960's and 1970's. They continued to improve in quality and kept getting smaller and smaller as well as cheaper and cheaper. History always repeaters itself! The compact disk was developed by the Philips Company of the Netherlands in 1962. The tape was self-contained in a housing. Recording and playback was at 1/ 7/8 inches per second. Like almost everything else that has to do with tape recording history, the Philips Company was not prepared for the demand. The cassettes, like most other major changes in tape recorders; were developed for dictation equipment. As it turned out everyone wanted them. For a while many companies attempted to develop equipment that would only work with their own tape recorders. Minifon and and Channel Master were two of many companies that tired this.

Just Like Minifon, Channel Master Marketed A Cassette Recorder That Would Only
Work With Their Own Cassette tape.

The idea of making less profit of the front end by forcing one to only be able to purchase cassettes from the company that made the recorder was a not a new one. It went all the way back to the time of wire and wax recorders. However, the more successful companies standardized so a standard third party tape would fit in their recorder. Many seen the handwriting on the wall as the market place was demanding standardization. It soon become quite evident that those who would not standardize recorders to specific cassette tapes would soon be out of business. It wasn't long before cassette tapes became standard and a tape recorded on one machine would fit in any machine.

Cassette Tape Recorders, 1960s 1970s
Cassette tape recorders in the late 1960's and 1970's flourished and flooded the market place. There were thousands of different brands and models. It wasn't long before micro cassette tapes came into being. It was at this point that tape recorders got really small.

Automatic Long Play Cassette Recorders
With Automatic Telephone Recording Controls, 1970s, 1980s

In the 1970's and 1980's there was developed what can be termed long play combo recorders that would plug into a telephone line. These recorders were modified recorders in which the tapes were slowed down so one could get more time out of them. Also installed in these recorders were telephone recording controls. They could plug into a telephone line and only record when the handset was picked up. The recording control was voltage regulated in that the recorder would know when the handset was picked up and when it was placed back on hook. In a completely enclosed recording system, this permitted the recording to only occur when the telephone was in use. Many of these recorders could also be used in a normal fashion. The Sony 12 Hour Long Play Automatic Telephone Tape Cassette Recorder was likely the most popular recorder of this type because of it's superior end results one could obtain.

Sony 12 Hour Automatic Telephone Tape Recorder
For simplified Automatic telephone recording in a long play format, the ATR-12 really meets the challenge! With exclusive modifications this unit offers excellent durability, unsurpassed long play sound quality, and features not found on any other unit of this kind. Just plug in to any standard telephone jack, place the unit in record mode and its ready to go. When any phone line is picked up, the unit automatically begins recording both sides of the conversation. The Sony work horse is still sold today.

Voice Activated Tape Recorders
Voice activated tape recorders were developed so that tape recorders could be turned on and off and only record when sound was present. This would save the tape for various types of covert recording. In an ever increasing number of features for tape recording products, the Spy Exchange And Security Center introduced the R2D2 portable long play automatic telephone tape recorder in the early1990's. Taking advantage of caller ID technology, this recorder would not only record both sides of a telephone conversation it would also log and time and date stamp all outgoing dialed numbers and incoming caller ID information. The R2D2 was a huge seller in it' time. It's still sold today.

The R2D2
The R2D2 is a ten hour long play automatic telephone tape recorder that records both sides of telephone conversations. The recorder goes on and off as the headset is picked up and placed back on hook. It also logs and keeps a record of incoming and outgoing numbers dialed as well as the time, date and length of call. Simply plug the recorder box in your phone line at the modular jack and it's ready to work for you. You then have a full 5 FULL HOURS of quality UNATTENDED recording time which also logs both incoming and outgoing telephone numbers with time, date and length of call. Turn the tape over and you have another five hours of recording time.

Micro Cassette Tape Recorders, 1970s, 1980s
In was Olympus who released the first micro cassette recorder in 1969 and boy was it small for it's time.

Ultra Compact Pearlcorder L400 Micro

Ultra Compact Pearlcorder L400 was a classy tiny recorder for it's time. In fact, it was one of the world's smallest recorders when it was released but had high-end state-of-the-art functions. Because of it's classy look, advanced functions and high end results, it became a favorite recorder for private investigators in the 1980's.The Spy Exchange And Security Center sold hundreds of these recorders in the recorder's hay-day in the 1980's and early 1990's.
Sony M-909 Auto Reverse Micro cassette Recorder, 1990's

Up until the the time the micro digital audio recorders came about, the Sony M-909 was the world's smallest tape recorder. It was used by private investigators and law enforcement for a number of different types of operations. The M-909 measures a mere 2 1/2 inches X 2 inches X 1/2 inch. It's features included voice activation and auto reverse. The Spy Exchange And Security Center sold hundreds of these recorders in the recorder's hay-day in the 1980's and early 1990's. The M-909 sold for about $495.00

Digital Micro Recorders, Late 1990's
It was in the late 1990's that digital recorders started to be produced. For over a decade computers had always been able to conduct some type of audio recording of one type or another. However, at the start of the digital computer age, computers were generally too slow and digital memory too small and expensive to really do any kind of audio recording suitable to the needs of investigative use. As memory got smaller and cheaper to produce, it wasn't long until small digital audio recording equipment hit the market place. The advantage of using digital recorders that recorded to memory over the old style analog cassette tape recorders is great. First of all, digital recording produces a much better sound quality. It can be duplicated without any loss of sound quality. Just as music products started to move from cassette tapes to CD-Rom, tape recorders developed into digital products. When you obtain audio in a digital form, it can be quickly and easily analyzed a lot easier. Various audio forensics can be applied such as digital PSE (deception detection) as well as various forms of statement analysis which has become a forensic science in and of itself. Moreover, voice recordings in digital form can be enhanced, background noise removed and they are much easier for adjustments in volume, filter and tone controls that can be made. A lot of investigative agencies today have the forensic software to do all this which was highly expensive to do just a few years ago. There are even software programs today that can take a digital audio recording and turn it into a typed transcript. That's something that was highly expensive and time consuming to do in the past.

The first digital micro recorders had to be plugged into a computer through the serial port which was time consuming and it took a lot longer to download the digital audio to your computer. As computers became standardized with USB ports, the digital micro recorders started using a USB plug to transfer the audio.

Diasonic was a leader in this field in the early days of high end digital audio recorders. Below is a photo of a very early Diasonic micro recorder.

Early Diasonic Recorder, Late 1990's

This early Diasonic hand-held recorder would record for an amazing 10 hours. It was highly superior to the other digital recorders that were rather low end that has come into the market place. The unit was voice activated, ran on AAA batteries and could be plugged into a wall outlet. It also came with a telephone recording control to plug it directly into a telephone line. The Spy Exchange And Security Center sold hundreds of these units.They retailed for over $400.00

Pen Shaped Recorders

The digital recorder age seen a huge surge in the production of tiny digital audio recorders. The overwhelming majority of them didn't make it simply because they were too low-end and didn't work well. Other then Diasonic, there were few digital recorder makers that were able to say in business long. In the late 1990's the pen shaped recorder shown to the left recorded for 8 full hours. It was quite a wonder for it's time but the unit was simply shaped like a thick pen.

There was a time period between the late 1990's and early 2000's that both small analog specialized long play and automatic telephone tape recorders sold well along side the new digital micro recorders that did about the same thing. At first, analog recorders out sold the digital tapeless recorders. However, slowly digital recorders took over the market. Analog recorders still sell today but the demand for digital tapeless recorders is about 100 to 1.

Third Generation Digital Recorders, 2000s
As research developed on digital tapeless recorders, the recorders got cheaper and cheaper with more and more memory in them. They also developed with better sampling rates and more features. In 2005 Diasonic released a new generation digital tape recorder that had a much higher sampling rate than the typical digital recorder. The small units were now just a little bit bigger than a Bic cigarette lighter. Features include up to 563 hour or recording time. That's an amazing 23 days! Just this year, the new generation TinyTek audio recorder was released in 16, 32, 65 and 120 hour models.

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Automatic Telephone Recording Ability.

New High Quality! The Stealth Pen

The Stealth Pen is a cut way above the run-of-the mill digital recorder pens in the market place today! It looks completely like a regular run-of-the-mill ink pen. However, when you push down the pocket clip on the pen, it starts recording. Push up the pocket clip and it stops recording. There are no lights or buttons. You can actually hand this pen to someone to sign a signed statement and they would never know there is a high quality super sensitive digital audio recorder inside the pen. This pen is thinner and gives you much higher quality recording ability that any other recorder pen in the market place.

New 18.5 Hour MicoDot Round Digital Recorder
With Leather Key Chain Cover, Voice Activation, Timed Recording And Law Enforcement/Broadcast Grade Results!
When it comes to micro small high quality digital audio recorders, it just doesn't get any better than this! The new MicoDot Round gives you highly superior law enforcement grade performance in the world's smallest package! The new generation high grade recorder comes with a leather key chain cover which you can take on and off. The new generation MicroDot Round features an extremely small size and weight with an amazing 18.5 hours worth of recording time. The broadcast quality sampling rate of up to 8 kHz with 2 bit ADPCM compression, a wide frequency range (100- 10000Hz) and an amplified super sensitive top quality built in mini microphone give you an amazing audio recording edge with top quality performance.

New Generation
120 Hour Black Stealth Pen 2 Recorder
Law Enforcement Grade Audio Recorder Built
Into Working Pen MSRP $295.00
Limted Time Super Sale! Your Cost Only $129.95

The all new super thin 1 GB, 120 Hour Black Stealth Pen 2 recorder has no lights or writing and gives you the ability to audio record while you are taking notes, writing out a statement or record while the working pen is in your pocket. This new revolution features one button recording which is hidden in the back of the pen. There are no other buttons on it and it appears to be merely a regular high end writing instrument to the naked eye. You can listen to play back with earphones or attach to your computer via the USB connection.

Watch Recorders And MP3 Players
In the last year, digital recording and MP3 technology has developed to the point in which recorders and MP3 players can be built into working watches. These watches will record a little less than ten hours and you wear them and use them just like a regular watch. It's come a long way since the time of the Minifon watch microphone that had a wire that went up your arm to a hidden analog tape recorder. Today, there are several different models of watch recorders for both the men and the ladies. Click here to review them all.

HotTeK Advanced Nano Digital Audio Recorder
In 70 Hour, 141 Hour And 282 Hour Models
Automatic Telephone Recording Ability
Time And Date Stamping And Programmable Timed Recordings!

If you want the world's very best digital audio recorder for investigative purposes this is it! This new generation advanced mutli-function digital audio recorder is called HotTek Advanced Audio because it's the hottest new recorder in the market place and really advanced! With the advanced features and amazing end results in recording ability, you will love both the micro tiny design and the high end results you obtain in audio evidence gathering. If you want a superior digital recorder a cut way above even the run-of-the-mill high end line, you'll find HotTek Advanced superior to anything else on the market.

New Generation!
Digital MP3/Voice Watch Recorder
Wrist Watch MP3/Voice Recorder/Player

You'll fall in love with this nine hour covert watch audio recorder! Investigative evidence recorder you wear! This is a very high quality fully functional watch with built-in digital recorder/player. 256Mb flash memory records 9 full hours of voice via built-in microphone and/or dozens of MP3 music files. Recording results is a cut above last year's model because the sampling rate is greater and he new generation mic built into the watch is much more powerful. You can record any sounds within 30 feet! Highly functional for investigators, law enforcement, journalists, attorneys, and business professionals who must conduct interviews

Fourth Generation Digital Recorders

As tape recorders developed, some developers lost their edge in the digital recorder revolution and innovation. Several other manufactuers entered the market place. Soon, a digital recorder had a micro SC card which would solve all the memory probelms and let you remove the card, place another one in it for continued use. Digital recorders got much better with more and more ways to store it's memory. The micro SD card gave digital recorders the ability to have just about as much memory and long play ability anyone would ever need. Parts are now so micro sized, digital recorders can not be built into almost anything. The standard digital telephone recorders now come with patch cords and mics so you can also record cell phone calls. And the evolution continues today.

New Generation StealthTek 2011!
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New Generation LawMate Brand-Law Enforcement Grade Audio Keycain Recorder Simple One Professional Grade Button Recording Fast USB downloads $98.00
New Generation 150 Hour Micro TinyTeK Recorder! Top Quality-Used By Intelligence Agencies Throughout The World! StealthTeK Audio Pen 5 Note Taker-Smarter, Better And Cheaper With Hidden Slide Activation On Clip- Also Works As A Pen
New Cell Corder! Word's First Wireless Cell Phone Recorder-Uses Bluetooth Wireless Technology New Generation! 71 Hour Covert
Micro/ Keychain Recorder

Just like Thomas Edison himself would be, you can be quite impressed also when it comes to an extensive line of the world's best and most complete selection of digital and analog audio recorders and accessories by checking out the subcatagories below. If you are in the market for any type of audio recorder, you can check out the links below or call our friendly customer service line at 512.719.3595.

Spy Exchange & Security Center
9513 Burnet Road Suite 101, Austin, Texas 78758
Phone 512-719-3595, Fax 512-719-3594
When In Austin, Texas--Stop By Our Huge Showroom

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Copyright: 2001, 2003, 2005, 2008, 2009, 2011
Thomas Investigative Publications, Inc. All rights reserved.
Thomas Investigative Publications, Trademark, 1981.
National Association Of Investigative Specialists, Inc, Trademark, 1986.
Spy Exchange, Trademark, 1999