The I.Q. & the E.Q.
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All you ever wanted to know about the Logic control & EQualizers in Personal Stereos
All you ever wanted to know about the Logic control & EQualizers in Personal Stereos
(last updated July 8th 2025)
Hi everyone, The feather touch feature and equalizers have always captivated me, especially on my very first Walkman, the Aiwa HS-G08. I will discuss EQualizers and IQ-Logic control in this article.
People like food and music because they are two of life's essentials. They are essential to people's lives. We all enjoy eating; some prefer simple meals, while others prefer gourmet fare. However, the majority of us are definitely unable to consume food that is prepared simply or in a natural way. As a result, we all enjoy seasoning our food. For the most pleasurable experience, we add a pinch of pepper here and a dash of salt there.
Gourmet food and hi-fidelity are very similar. Clarity is one of the components of Hi-Fi sound, but it is insufficient on its own. We also need the bass, the beating heart of the music! The music will sound flat without the bass, lacking any drama, excitement, or presence. When the bass is set just right, the music will come to life, and you will feel its presence. Imagine it as enjoying a peaceful meal with a fine bottle of wine or a nice beer.
With a good hi-fi system, you will get the perfect combination of heart and soul. The majority of people season their food with salt (the highs), while others prefer to use pepper (the Bass). The majority of hi-fi systems have a "treble" dial for highs and a "bass" dial for lows. However, some individuals need more spices in their food, such as in their music. Thus, a graphic equalizer will be used.
Graphic Equalizers and what they can do for You
The human ear can hear frequencies from about 20 Hz all the way up to 20,000 Hz. Our stereo system, to a greater or lesser degree, produces these sounds with some limitations. There are three ways to manipulate sound in classic stereo systems: Loudness, Bass & treble, and Graphic Equalizer.
Loudness
Loudness is usually a single switch to boost the lows and highs at the same time without the ability to control them individually. It boosts the bass and treble indiscriminately from the midrange down or from the midrange up. Each actually affects about 20~30% of the entire frequency spectrum. However, the ear does not perceive sound linearly as the volume is increased or decreased. As volume level decreases, the lowest and some of the higher frequencies appear to drop off sooner than mid frequencies. Therefore, loudness equalization was created to boost the high and low frequencies at lower volume levels to compensate for that loss.
Bass and Treble
The bass and treble controls are essentially a 2-band equalizer. The bass control is usually set to vary the level of audio in the low range - a band of frequencies centered around 100 Hertz. The treble control acts similarly, but its band is centered around 10,000 hertz in the higher range. As the level of the control is increased or decreased, the band of affected frequencies generally widens or narrows. Most low-budget players will use the bass (100 Hz) and treble (10 Khz) controls as their main tone control. In most players, 100 Hz is not rich enough to add excitement to your music. In others, distortion may occur. To extend the experience, some players will use Super Bass or Bass Extender (50 Hz). Essentially, Super Bass is a control that emphasizes very low bass sound, with the effect greatest around the 50 Hz point. As a result, Super Bass delivers deep, rich bass with a minimum of distortion or distracting equalization variations.
Graphic Equalizers - "GEQ"
A Graphic equalizer can make your portable stereo sound the best and apart from the rest. The graphic equalizer gets its name simply because its sliders will shape a graphic form of the audio output. The equalizer gives you the ability to control individually different parts of the frequency spectrum. This control lets you adjust the sound to maximize your listening experience. Basic GEQs have low frequencies, mid-range frequencies, and high frequencies.
A basic 3-Band equalizer gives you the ability to control the bass, mid-range, and treble. Low frequencies are adjusted by the bass (100 Hz) – usually, its sliders are on the left. The Midrange frequencies are adjusted by the mid (1.0 KHz) – usually, its sliders are in the center, and the higher frequencies are adjusted by the treble (10 KHz) – usually, its sliders are on the right. A 5-Band equalizer gives you more control with added frequencies (100HZ, 330HZ, 500HZ, 3.3 KHz, and 10 KHz).
Graphic Equalizers are really just a series of 5 or 10 volume controls. Each equalizer volume control affects only one area of the whole frequency spectrum. Each of the sliders boosts or cuts a small section of the audio spectrum at a predetermined frequency. The GEQ is an important tool for enthusiasts or audiophiles, generally used for emphasizing or reducing audio sounds, instruments, and/or voices.
The biggest problem with a personal stereo player is usually the headphones. (For reference see my post, "Is it all in your headphones?") If they're cheap, they tend to lack the ability to reproduce bass or highs. With the aid of an equalizer, you can make your headphones ideal, and you can compensate for a 125 Hz boom or for a loss of high end. In addition to restoring impact and drama to your music, you can easily adjust all the frequency bands to increase excitement, dramatic intensity, and openness. This will make your listening more enjoyable and attractive. If your low bass is down 3 to 6 dB, you'll miss the excitement, warmth, and fullness of strong bass. By increasing the signal with an equalizer, you're reviving inadequate recordings or reproductions. To compensate for poor earphones or headphones, most people will use the famous smiley face curve.
The smiley face curve
Particularly in the 1980s electronic music era, the smiley face curve could provide you with more bass and treble response from headphones that didn't extend as low or as high as you wanted. The majority of 5-band graphic equalizers were the best available and were exclusively included in player models between 1984 and 1987. Music lovers or audiophiles who never use the recording feature or listen to low-fidelity sources like the radio were the target audience. Models with radios and recorders were primarily equipped with 3-band GEQs. Nonetheless, as the newest invention of the 1980s, both 3-band and 5-band GEQs were incorporated into high-end models. As technology became more compact by 1988, the Super Bass was widely used, and most GEQs were left out in favor of the simple bass treble option.
The First maker of the walkman GEQ
Not many people know, but the first company to introduce graphic EQ in a Walkman was Aiwa, not Sony. (Sony, however, was the pioneer to introduce the first portable Graphic EQ module—a stand-alone GEQ device, the SEQ-50! the SEQ-50 was based on a car stereo GEQ. It was a unique and awesome solution, but it was not very practical to carry along with another Walkman unless you're a serious enthusiast or maybe a full-time DJ). Sony's rival, National Panasonic, soon replied to Sony's SEQ-50 with their own GEQ the RD-EQ5, also a stand-alone GEQ, but it was made only for the RX-S70. The stand-alone GEQ paved the way for AIWA to come up with the idea to combine GEQ in their models.
A Standalone GEQ device: the Sony SEQ-50 with DC2 Walkman
Panasonic RX-S70 with its 5 options. #2 is RD-EQ5 with a 9,000 Yen tag price
National Panasonic's RD-EQ5 stands along GEQ
The First model with GEQ
The year was 1983, and very few people had seen the big brother of the Back to the Future movie model: the HS-P7, with its 5-band graphic equalizer on the back. This player was Aiwa's first attempt to show Sony who's the boss and to take the lead in innovation. This model was an exclusive Japanese model and paved the way for the world's most advanced personal stereo in 1985, the Aiwa HS-G8 (G500 in the US/ G08 world). Aiwa and their fans really liked the GEQ, making this unique feature a standard premium feature. They tagged them as "G Series" which is short for "Graphic EQ".
HS-P7G & HS-P7 - the equivalent predecessor models of the HS-G8 (EQ) & HS-P8 (no EQ)
AIWA CassetteBoy HS-P7G (Left) & HS-P7 (Right) - Inside comparison
By 1986, Aiwa's new generation of headphone stereo, the HS-9 (HS-600 in the US and HS-09 world model) series, included more than 6 models with GEQ, ranging from 5-bands to 3-bands: J09, T09, and G09 are 5-band EQs; G55 is a 4-Band EQ, and G35 is a 3-band. The later had a huge success and received 4 revisions/versions over the next 6 years.
Altogether Aiwa made 16 models - 8 High-end players and 8 mid-range players.
By 1988, Aiwa was cutting their losses and skipped a year to 1989, when they dropped the GEQ feature altogether in favor of their famous DSL (Dynamic Super Loudness), which debuted in 1987 with the successful PX10/PX101/PX700. It was an excellent feature up until their PX50/PX505/PX900 came along (1990), and after that, it was a downward spiral for Aiwa. Although some people will consider the PX1000 to be Aiwa's top player, unfortunately, it doesn't have GEQ but rather sound presets with just a show-off spectrum analyzer.
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| The successful PX101/PX10/PX700 series |
Sharp and Toshiba
Sharp and Toshiba were the first to jump on the bandwagon for a free ride on the success of Aiwa's HS-P07 with their own versions. Unlike Aiwa's metal build, Sharp and Toshiba players were made mostly of plastic only; however, sometimes their lid was covered with a sheet of metal to give them some weight and feel.
Sharp saw the great potential in GEQs and offered 4-band EQ players as standard. They first came up with the JC-7 (JC-77) with its separate tuner pack in December of 1984. In 1985, Sharp introduced the JC-R7 (JC-790) recorder and the JC-N7 (JC-786) player: slick-looking with vivid 80's designs and colors. In 1986, the JC-N8 (JC-820) was a 5-band GEQ, and in 1987, the JC-850 (JC-849) was a 3-band player with a Corvette-like body and color. Also the similar JC-K10 (JC-10H) with 3-band EQ. The last Sharp player with a 3-band EQ and Dolby C was the Japanese model named "Being Hi-Fi", the JC-50 from 1990.
Left to right: JC-R7, JC-N7, JC-77, JC-R8/850
In June of 1985, Toshiba introduced two models, the KT-AS7* (KT-4075/KT-V570), a 5-band GEQ player with a radio, inspired by Aiwa's HS-J7, similar in many aspects, and the KT-RS7 (KT-4085/V580), a 3-band GEQ recorder. In July of 1987, their EQ line was 3-band only (RS30, PS30, PS20, and PS10). Unfortunately for Toshiba and us collectors, Toshiba continued with only low-end models and did not stick to the 80s hip that Aiwa's direction was. Toshiba gradually withdrew from the competition. Apparently, for Toshiba, it was just a temporary hype in the market.
*Note the model #, As with any rivalry, Toshiba was keeping an eye on Aiwa's prosperous endeavors as a fashion brand with a youthful vibe. The KT-PS9, which is nearly identical to the Aiwa HS-J9 in terms of its triangular design but oriented in the opposite direction and its chrome finish, is just one example of a model concept that Toshiba borrowed from Aiwa.
Toshiba Walky KT-AS7
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| Toshiba Walky KT-RS7 |
Kenwood and AKAI
Kenwood, on the other hand, was trailing Aiwa. For every top-of-the-line model made by Aiwa, Kenwood had its own version. However, Kenwood themselves never manufactured any headphone stereos at all; they were all OEM versions made by Aiwa (i.e., CP-707 aka HS-J09, a 5-band EQ from 1986, and CP-700 aka HS-J101, a 4-band EQ from 1987, etc.). The sole exception was the OEM Toshiba "CP-G5" from 1984.
Left to right: Kenwood CP-707, CP-700 silver & black, CP-G5
That same year, 1987, AKAI offered two bulky 5-band GEQ players: the PM-R3 and the radio version PM-R5 (aka OEM: Roberts PS150 and Sansui FX-W51R) with a nice, classy 80's look. Additionally, there are two 4-band GEQ players—the PM-R8 and the PM-R9 (with radio)—that have the odd addition of Super Bass. Despite being inexpensive plastic players, they have great sound quality that is appropriate for a respectable company like AKAI, which is well-known for its consumer semi-pro cassette decks.
AKAI PM-R5
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| Sansui FX-W51R |
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| Roberts PS-150 (Figure 5 is shared by all of them) |
National Panasonic
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| 3 Preset Equalizer: the RQ-JA5 |
Panasonic, Sony's main competitor, introduced a 3-preset equalizer in 1984, the RQ-JA5, but it wasn't "a" graphic EQ. Two years later, in 1986, they introduced 3 players with 5-band as standard EQ: the RQ-JA2, the radio version RQ-SA15, and the RX-SA77. As usual, Aiwa's cutting-edge technology and fashionable design were unmatched. Similar to Sony's WM-60, which felt plastic, the early J series were too heavy to fit in your shirt pocket and were primarily made of plastic (the lid was the only metal component). But all in all, they sounded rather nice. In 1987 they introduced two more fashionable players: the RX-SA78 (radio version), the successor of the SA77, and the RQ-JA65, a basic player model, and the RQ-SA79, a 3-band model. They kept adding 3-band budget units, sometimes with XBS or his more sophisticated version, S-XBS.
Panasonic Jump RQ-SA15 in Red & Tourqize
National Panasonic Way RQ-SA77
Panasonic TNT (Touch n' Tune) RQ-SA78
Panasonic RQ-JA63
SONY
Sony's big surprise—which isn't really surprising given their corporate and unfriendly attitude toward their customers—came in the form of the WM-60 (WM-F60/F80), their GEQ player, which was only released in late spring 1986. With the same brushed metal finish, EQ position, and even the same metal stripe on the left, the WM-60 was obviously a bad replica of Aiwa's HS-G8. The WM-60 wasn't very popular (particularly in Japan) for two reasons: it was too bulky, and it had a plastic feel to it. Additionally, customers enjoyed Aiwa's more sophisticated and streamlined HS-G8 from 1985, which felt pricey and was long-lasting (nearly 90% made of metal). After six months, After learning their lesson, Sony unveiled the WM-104 in October 1986. This slimmer 5-band player, which was based on the 1985 model WM-100, was only available in black and white. At that point, Aiwa was dominating the market with the wildly popular HS-J9, which came in six color options. To level the playing field, Sony released the WM-36, a low-range Walkman with a 5-band GEQ player, in 1987. Additionally, they sealed the deal with Sony's GEQs in 1992 with the introduction of the TCP 470, a cassette-corder with a 5-band GEQ. After acquiring Aiwa, Sony attempted to show its relevance in the personal stereo market with the TCP 470, but it was too late for GEQs in 1992. Similar to the MiniDisc format versus the MP3, Sony was not prepared for the current market demand and the future of graphic equalizers, which are as trendy as a young person.
From right to left: Sony WM-104, WM-60 (WM-80 in the US)
WM-F60 (WM-F80 in the US)
Sony WM-36
Sony's TCP 470 Last GEQ - Business Recorder
Finally, something fun to help you get the best out of your EQ, A link to a nice Quiztones: http://www.audio-issues.com/music-mixing/enhance-your-ears-for-superpowered-eq-skills/ Enjoy.
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The List!
A comprehensive list of Graphic EQ Walkman manufacturers:
5-Band: HS-P7, G08, J09, T09, G09.
4-Band: G55, J101, T101, G101, J45, T45, G56, G56MkII, G57.
3-Band: G35, G35mkII-III-IV, G36, G39.
DSL-EX: HS-PX10/101, PX20, PX303.
DSL 3: PL20, RL30, PL303.
DSL 2: PL35, RX50, PX505, PL55, PL707, PL770, PX1000.
AKAI
5-Band: PM-R3, PM-R5.
4-Band: PM-R8, PM-R9.
FISHER
4-Band: PH-S120, PH-S320 1987
3-Band: PH-31
JVC / VICTOR
5-Band: CX-F3K, CX-F30,
3-Band: CX-2K, CX-F101, CX-F200, CX-F303, 1993
KENWOOD
5-Band: CP-G5, G5TV, CP-707
4-Band: CP-700
DSL: CP-9RC
NATIONAL PANASONIC
5-Band: RQ-JA2, RQ-JA15, RX-SA77, RX-SA78, RQ-JA63,
3-Band: RQ-V175, RQ-V158, RQ-V154, RQ-P164, RQ-V165, RQ-P175, RQ-J175, RQ-V162, RQ-V150, RQ-P155, RQ-V152, RX-SA79. RQ-V170, RQ-V320, RQ-V340.
SANSUI
5-Band: FX-W51R
SANYO
4-Band: MG-P600D, JJ-P3.
3-Band: MG-R80, MG-R77, MG-R74, MG-R67, MG-R906D, MG-P28, JJ-P20, MG-P34.
SHARP
4-Band: JC-77, JC750, JC-790 (JC-R7), JC786 (JC-N7), JC-N8, JC-N5
3-Band: JC-50, JC-K10, JC102, JC110, JC196H, JC-213X, JC-510, JC516, JC518, JC519, JC-R8 (JC-850).
SONY
5-Band: WM-60, WM-F60/80, WM-36, TCS-470.
3-Band: WM-F18, WM-F28, WM33, WM-F47, WM-F59, WM-69.
TOSHIBA
5-Band: KT-AS7 (KT-4075/KT-V570),
3-Band: KT-RS7, KT-RS30, KT-RS40, KT-PS14, KT-PS12, KT-PS18, KT-4027, (KT-V940).KT-4529, KT-4036 (V630), KT 4038, KT-4047, KT-4066, KT-4568, KT-4058 (KT-V850), KT-V4068 (KT-V860), KT-4085 (V580), KT-4087 (V780), KT-4087MKII (V780 MKII), KT-4067 (KT-V760), KT-4098 (KT-V890), KT-V4094.
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The IQ – IC Logic Control
A brief history
In the early days of consumer electronics, early cassette drive manufacturers built mechanical products; the operating keys were used to physically move part of the cassette mechanism. the main concept was mainly mechanical. Then later on in time came the electronic era. The discovery of the transistor and the development of the integrated circuit both contributed to the process. Since Jack Kilby’s invention of the first integrated circuit (IC) in 1958, there have been unprecedented technological advances. When the Walkman was invented at the end of the '70s the mechanism was a simple mechanical push-button device. While entering the 80s, the miniaturization of the industry started to develop rapidly.
What is Logic Control?
Many people mistakenly equate Logic Control with Soft Touch (Feather Touch). They are 2 different concepts.
Feather Touch: Aka Soft touch refers to a part of the mechanism only, sensitive flat buttons which send an electrical pulse to operate the device. Soft touch has electronic control buttons that make cassette operation easier, it also allows remote control capability. However, it is only at the hardware level.
Logic Control: Basic LC operation is a feature that prevents the activation of the "wrong button". Any faulty operation is prevented. The logic control circuit remembers which buttons have been pushed but permits only the correct sequence of machine operations to occur, thus eliminating any chance of operator-control error (damage to the unit itself). With this important feature of LC, any button can be pressed at any time without going first to the STOP mode therefore without damaging the tape or the machine.
IC Logic Control: Aka Full Logic Control is an advanced LC version it is more like The Software that "thinks" i.e. the system's brain. IC-LC remembers a vast array of commands and their Statuses. It has more room in a small chip to remember (aka ROM - Read Only Memory). The "Logic" system ensures that when you press "forward", the deck will always move forward, regardless of which side of the tape is currently playing. One more thing a full logic control does is that when you press the play button on a player with full logic control, it quietly whirs while taking any slack in the tape, and then it engages the play mechanism.
The First Logic control Walkman
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WM-7 Japanese brochure:
Feather Touch for 36,000 Yen |
Sony released the WM-7, also referred to as the Reverse Walkman, in October 1982, which was the first feather-touch operation Walkman. Also, it's important to keep in mind that, up until that point, all Sony Walkmans were unidirectional players; thus, the first auto-reverse Walkman. Apart from the auto-reverse, it was supposed to be a revolutionary concept idea, but despite what the Sony catalog called it, it wasn't a true logic control. Furthermore, the catalog description described how autoplay operates, and it is unquestionably not the logic control that we are all familiar with. Instead, it was merely a simple feather-touch mechanism devoid of any logic or sophistication; however, Sony claimed that "the mechanism allows you to skip the process of pressing the stop button from fast-forward or rewind and go directly to play." Instead of having any truly sophisticated features, the WM-7 was more akin to an auto-reverse with a sleek appearance. Instead, it was the first portable player to use a remote control, but it was only a basic two-button remote that could be used to play (A or B) and stop.
An improved version, the Pressman TCM-7 (and the Pressman TCS-7/370), was later created in early 1983. They called it the Logic Control Mechanism, or LCM; it was an early and simple LC, but even though it was more advanced than the Reverse Walkman WM-7, it was still a very basic logic control.
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| TCM-7 LCM - Logic Control Mechanism - Second generation |
SANYO MR-JJ11/JJ22 Touch
The first feather-touch logic control, known as the "JJ Touch," or MR-JJ11 Player and MR-JJ22 Recorder, was released by Sanyo two years later in the summer of 1984. Sanyo did not actually manufacture this model! Instead, it was a joint venture between Aiwa and Sanyo, and Aiwa produced it as OEM in order to test the market (it was the predecessor to the HS-8 series). Because of its corner triangle, the JJ Touch's design was somewhat reminiscent of the Aiwa G8. At a starting price of ￥33,000 yen, or about $500 US, this special collaboration and extremely rare personal stereo were completely unknown in the Japanese market. By contrast, the 1979 Sony TPS-L2 cost 33,000 yen, and the WM-7 cost 36,000 yen. Sanyo subsequently authorized its production and manufacturing, and Aiwa proceeded with the 8 series.
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| Sanyo JJ Touch: MR-JJ11 Player |
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| Sanyo JJ Touch: MR-JJ Recorder |
The Sanyo concept was always way ahead of its time. The JJ-P101 is a remarkable piece of electronics that is the successor to the JJ Touch line. Instead of a button, this player uses a thin film that can be operated with the lightest touch.
AIWA's Feather Touch Full Logic Control
The Feather Touch and IC Full Logic concept models in one unit were first introduced by Aiwa with the world-famous HS8 line (J8/R8/G8/P8) a year later. They also expanded it to include the Walkman's first full remote control. In contrast to its predecessors, Aiwa's HS8 stylish series is far more sophisticated and cutting edge. The ROM memory of the Aiwa chip "remembers" a wide variety of commands; it takes into account the initial state and the current logic mode position, as well as the type of signals. It is, in other words, pretty sophisticated for its time; it took Sony nearly two more years to construct the WM-109, a similar unit.
The Aiwa Hi-Tech Touch - Full Logic Control Feather Touch - Nothing's Even Remotely Similar
The Aiwa CassetteBoy flagship: HS-G8 / G08 / G500
Despite its global success, the 8th series (model G500 in the US/G08 world) was very costly to produce, which left Aiwa in a precarious financial situation. Since the IC chip was a relatively new and costly technology in small devices, it was only used in high-end models. It was innovative for its time. As a result, this new technology was absent from the following group of headphone stereos. Despite this, Aiwa's drive for success and willingness to take big chances paid off with the new 9 series, also known as the 600 in the US or 09 world players. These personal stereos were so feature-rich and exceptional that they outperformed the competition. That was insufficient for Aiwa, and their new 10 series, which included the well-known PX10, was born shortly after. For Aiwa, this was the pinnacle of success.
The 10 series: Right to left: HS-JX10, HS-J10, HS-PX10, HS-PL10
World's first headphone stereo with full-logic remote control of all cassette functions (from AIWA Catalog)
Thank you for reading this article, please feel free to comment below. Cheers, and Be well :-)
Sincerely,
TheLion
This Article was last updated and fixed July 9th, 2025
2013 © All rights of the article are reserved to TheLion
2013 © All photos are copyright of their respective owners and shown here for illustrative purposes only.
