Yamaha YM2612 Specs and Review

The Yamaha YM2612 FM synthesis chip was built in the 1980s as a cost-reduced sound engine similar to that in the popular DX7 synthesizer. It was manufactured to provide a voice for several computer games and computer systems.

The Yamaha YM2612 is a dependable six-channel FM synthesizer sound chip. This sound chip is part of Yamaha’s OPN family of FM synthesis chips. Yamaha developed the product as a voice for computer games and systems. The YM2612 features an 8-bit digitized audio channel.

Sega’s Mega Drive and Genesis video game consoles use the YM2612. Various arcade game systems, including the Mega-Play and Sega System 18 and System 32, also use the product. The computer series of Fujitsu’s FM Towns computer series features the YM2612 too.

Read on to learn more about the Yamaha YM2612, its features, specs, and its pros and cons.

About the Yamaha YM2612

Yamaha YM2612

The YM2612 features 4 operators per channel, analog stereo output, 2 interval timers, and a low-frequency sine-wave oscillator. Yamaha designed the YM2612 with programmable stereo sound per channel on either left or right or both with a center stereo sound.

A downgraded version of YM2608, the YM2612, has no accumulator-equipped sound mixer. The YM2612 lacks the ADCPM channel, SSG components, and GIO ports. The company designed it instead with a time-division sound multiplexer and a built-in 9- bit DAC.

The FM synthesis block of the YM2612 is YM2203C’s FM block extended version with added 2 channels and a stereo output DAC.

Yamaha YM2612 Specs and Features

1. FM Channels

The Yamaha YM2612 FM channels are divided into two sets by 3, channels 1 to 3 and 4 to 6. The last of each set, channel 3 and 6, utilizes a different frequency from that of the first 2 channels of each set.

Assigning different frequencies for channels 3 and 6 allows the harmonics. The use of multiple frequency modulations channels can create chords used to produce single notes for the chip.

2. Interval Timers

The YM2612M features 2 interval timers that create waveforms in various durations or resynchronize waveforms through the interrupt-based timers. These will create new waveforms and modulations with pitch values.

3. Stereo Output Capability

The YM2612 can direct the sounds from FM or DAC to either the right, the left, or both outputs.

4. LFO or Low-Frequency Oscillator

The YM2612 oscillator’s frequency is below 20 Hz. This frequency creates the rhythmic pulse to modulate the sound or the audio effects.

5. YM2612 Operators

The YM2612 features 4 operators per channel. So that the YM2612 has a total of 24 operators covering the 6 channels. The different operators interrelate following the different algorithms.

6. YM2612 Compatibility

The YM2612 is compatible with the Yamaha DX and TX synthesizers. You should test the chips with your prospective synthesizers before buying the product.

7. Built-in 9-Bit (DAC)

The YM2612 provides a built-in 9-bit Digital-to-Analog Converter (DAC) that uses a time-division multiplexer. This component plays a sequential sample which launches the crossover distortion in the output.

The Yamaha YM2612 is a part of the OPN family of FM synthesis chips. The chip provides an 8-bit digitized audio channel. Yamaha developed the YM2612 as a voice for computer games and systems.

Pros and Cons of the YM2612

Pros

1. Affordable

The YM2612 is cheaper as it is a downgrade version of YM2608 compared to the other Yamaha series of sound chips.

2. Powerful and Versatile

The YM2612 is exceptionally powerful and versatile, even when it was released in 1988. It was the best mass-market sound chip that can network according to 8 different algorithms.

It allows MIDI input to connect a sequencer, keyboard, and other MIDI instruments. A USB-type B cable powers the instrument.

3. Provides Real-Time Music

The YM2612 used in Sega console games allows music generation in real-time. This music generation gives more clarity and depth to the audio. There are no delays in the sound and music when played through the different computer games.

4. Basis for Good Sound Timbers

Some prefer the distorted output of the YM2612 because they can use this with good programming. They can produce a different and rare sound timbre if they do it properly. [1]

Cons

1. The YM2612 Is Not 100% OPN Compatible

There are no dedicated ADPCM channels for playing sample video since the SSG channels do not exist from the YM2612. Instead, the 6th channel serves as the PCM through the DAC, which is not 100% compatible and may cause sound issues. [2]

2. Presence of a Distracting Noise

The YM2612, when operated, produces a soft, persistent white-noise. This noise is due to the time-division multiplexor cycling through all of the FM channels that cause a distraction. The noise becomes more distinct when the chips are not in use.

3. Limited Notes

You can only play 6 individual notes at one time since the YM2612 only has six channels. If you press more than 6 notes simultaneously, the new note will overwrite the first key you pressed.

4. Downgraded Capability

The features and performance of the YM2612 are reduced because it is a downgraded version of YM2608. The YM2612 does not have an accumulator sound mixer that mixes the 14-bit floating-point output of the channels. This occurrence will result in the “ladder effect.”

Also, it does not have Rhythm Sound System, ADPCM channel, SSG components, and GPIO ports

5. No Buffering or Timing of Samples

The YM2612 model does not supply buffering or samples, so the host processor’s software performs all buffering and frequency control.

6. Creates Glitches and Distortion of Sounds

The YM2612 uses a simple time-division sound multiplexer that shortens the 14-bit channel output to 9-bits, then it passes the channel in sequence using a built-in DAC. This cutting of output samples triggers glitches at the edge of the waveform that affect the sound’s quality.

YM2612

YM2612 Alternatives

1. YM2608

The YM2608 is an enhanced version of the YM2612. Yamaha developed this sound chip that belongs to the Yamaha OPN family of FM synthesis chips. This model came after the YM2203. It is mostly used in the PC-8801 and PC 9801 computer series of NEC.

It has four internal modules, 4 operators per channel, 6 FM channels, dual interrupt timers, and low-frequency oscillators. The chip works on 8 possible operator interconnections to produce varied types of instrument sounds.

2. YM2203

The YM2203 has 3 channels, unlike the YM2608 and YM2612. Yamaha developed this chip to serve as the model for the OPN family of FM synthesis chips’ succeeding sound chips.

The YM2203 features 4 operators per channel, 2 interval times, 3 FM channels, and an SSG module. This model was used in arcade games and NEC computers.

3. Yamaha Y8950

The Yamaha Y8950, also known as the MSX-Audio, is a sound chip with 9 voices of Yamaha FM. The chip offers the following:

  • Built-in AM oscillators and vibrato
  • Built-in 8-bit input and output ports for keyboard scanning
  • 4-bit general-purpose input and output ports

The product features 2-sound generator modes, 2 general-purpose timers, a single power supply, 64-pin SDIP, and CMOS LSI.

4. YM3438

The YM3438 is a modified CMOS version of the YM2612 with louder sound output and no “ladder effect.”

The company designed the YM3438 using a newer CMOS process than used in the YM2612 PMOS process. This CMO proves to be more power-efficient. The YM3438 runs more smoothly too.

5. Other Yamaha Sound Chips

There are other Yamaha sound chips, such as the Yamaha YM2149, Yamaha YM3439, and other earlier versions:

POKEY

The Pot Keyboard Integrated Circuit (POKEY) is one alternative to the YM2612, currently being used in Atari 8-bit family computers and Atari arcade games.

It can generate 4 distinctive voices with steady frequency. These voices can either be modified with distortion or clear ones.

POKEY sound chips are used in Missile Command, Centipede, Asteroids Deluxe, Atari systems, and Gaunlet.

Philips SAA1099

The Philips SAA1099 is a sound generator with a 6-voice sound chip. The company developed it in the 80s. It can produce many waveforms. The audio output can be via a fully independent stereo.

Oki MSM6295

Oki Electric Industry Co., Ltd, a Japanese company, developed the Oki MSM6295. This item is also known as OKIM6295. It features a 4-channel ADPCM sound chip used in arcade games in the early 1990s.

Frequently Asked Questions

How Many Channels Are Used in the YM2612 Processor?

The YM2612 has a digital audio channel (DAC) and 6 FM channels that interact with the other parts of the sound chip to produce the sound.

How Many Instruments Are Used in the YM2612?

Like many, the 6 FM channels are each made up of 4 preset waveforms. You can alter these waveforms by changing the attack rate (AR) registers, release rate (RR), primary decay (DR1), and secondary decay (DR2).

Since you can change almost everything in the YM2612, you can produce any kind of FM sound.

Can the YM2612 Produce Percussion Sound?

Yes, since the YM2612 allows alteration in almost all its parts. You can use FM Channel 3 in a special mode and the registers to generate your percussion sound. The YM2612 does not have a built-in percussion sound. Thus, you should generate all sounds.

Is YM2608 Better than YM2612?

The Yamaha YM2612 may be a downgraded version of YM2608, but it has its good points. Aside from the lower price, you can use it in different games and computer systems. As earlier mentioned, you can use distorted sound to produce sound timbres with good programming.

Tips in Maintaining the Yamaha YM2612

Yamaha YM2612 Specs

1. Avoid Getting the YM2612 Wet or Exposed to Moisture

You can damage the YM2612 when it gets wet, or moisture gets into it. Take care not to place it on the dining table with kids around. They might accidentally spill water and soak your sound chip.

2. Turn Off Your Device If Not in Use

Turn off your computer or console when not in use. You do this step to avoid overheating your IC and damaging it. Prolonged exposure to heat is not good for your device and your YM2612.

3. Clean Your Computer or Game Console with the Recommended Cleaning Methods

Do not clean your device with water. Do not use chemicals on your PC. Use only the recommended cleaning solutions. The best thing to do is wipe with a dry cloth or dust it off with a dusting material.

4. Keep Your Device Covered to Keep Your YM2612 Intact

Make sure that you cover your Sega console device from dust. Otherwise, dust may penetrate your YM2612 sound cheaply and affect the sounds produced.

5. Place Your Device in a Safe Place to Protect Your YM2612

  • Do not place your device where it can be exposed to too much sunlight, moisture, and water.
  • Avoid areas that have heavy foot traffic. The chances of the device getting bumped and falling is great.
  • Avoid leaving your device outdoors overnight as it may gather moisture.

6. Plug Your Computer or Sega Console Game Properly

When plugging your device, make sure you are plugging it in a safe outlet. Ensure that your wires and cords are not tangled and are kept away from foot traffic.

You have to avoid tripping on the wires, as this will cause a sudden shutdown of electricity that can damage your device. Improper shutting off also damages your YM2612.

7. Use the YM2612 and the Device Properly

Improper use of your device means improper use of the YM2612. Ensure that you do not overload the outlet. Otherwise, you might burn your device with the YM2612 in it.

Give time for your device to rest. It may be a machine, but overuse shortens the life of your computer or game console.

8. A Professional Technician Must Check Your Device Regularly

When having problems with your device’s functionality, have a skilled repairman check it to avoid further damage. The technician should check your device, including your YM2612. Do not do a DIY unless you are an expert too. A professional should do it for you. [3]

Conclusion – Yamaha YM2612

The Yamaha YM2612 sound chip is a dependable six-channel FM synthesizer. It features an 8-bit digitized audio channel and is a part of Yamaha’s OPN family of FM synthesis chips. Yamaha has developed the product as a voice for computer games and similar systems.

The YM2612 is exceptionally powerful and versatile, even when it was released in 1988. It was the best mass-market sound chip that can network according to 8 different algorithms.

Again, here are the tips to help you maintain your Yamaha YM2612:

  1. Avoid Getting YM2612 Wet or Exposed to Moisture
  2. Turn Off Your Device If Not in Use
  3. Clean Your Computer or Game Console with the Recommended Cleaning Methods
  4. Keep Your Device Covered to Keep Your YM2612 Intact
  5. Place Your Device in a Safe Place to Protect Your YM2612
  6. Plug Your Computer or Sega Console Game Properly
  7. Use the YM2612 and the Device Properly
  8. A Professional Technician Must Check Your Device Regularly