Megatron's right-hand man. A loyal and cold subordinate, he is often tasked with spying on the Autobots, which he often accomplishes with the aid of his cassette minions Laserbeak, Frenzy, Rumble, Buzzsaw and Ratbat. 
In the Headmasters anime, an aide to Galvatron.

~!Following his fight against Blaster in the Headmasters anime and the subsequent destruction and death of both of them, he is rebuilt and renamed to Soundblaster (サウンドブラスター), aka "New Soundwave" in the Omni Productions English dub.!~

His altmode is a cassette player.

It is the year 2005. Twenty-one years after the heroic Autobots and the evil Decepticons resumed their neverending war on planet Earth, the Decepticons have conquered the robots' home planet Cybertron. After a surprise attack by the Decepticons, both factions wage a gruesome battle at Autobot City. In the midst of the battle, Autobot leader Optimus Prime dies during his fight with Decepticon leader Megatron. The Autobot Matrix of Leadership is then passed on to second-in-command Ultra Magnus. Meanwhile, a badly-damaged Megatron is jettisoned by Starscream into deep space, where he encounters the planet-eating robot Unicron and is reborn as Galvatron, the new Decepticon leader. With Galvatron's reign on the rise and Unicron's imminent arrival within Cybertron's orbit, the Autobots must act quickly and protect the Matrix or face total annihilation. 
(Source: Anime News Network)

Franklin W. Welker is an American voice actor. He is responsible for a broad spectrum of character voices, noises, and other vocal effects that have appeared over the last 40 years in American television and motion pictures. He is listed as the number one "All Time Top 100 Stars at the Box office" in terms of the total revenue his films have generated. His work in over 90 films has put him ahead of Harrison Ford, Tom Hanks and Samuel L. Jackson.    n the 1980s, Welker voiced Megatron, Soundwave and his cassettes, the Dinobot Sludge, and Galvatron in place of Leonard Nimoy (Season 3) in the Transformers cartoon. In this he formed a team with Chris Latta, who voiced Starscream, Megatron's second-in-command. In 1988, Welker did the voice of Rulon leader Krulos in the TV-series Dino-riders. In this cartoon he again formed a team with Chris Latta, who (coincidentally?) voiced Rasp, Krulos' second-in-command. In G.I. Joe, Welker also teamed with Latta. (Other actors who featured in Transformers, Dino-riders and G.I. Joe are Jack Angel, Charlie Adler and Peter Cullen.) In a famous goof from Transformers, Soundwave's unmodulated voice was revealed to be nearly identical to that of Dr. Claw of Inspector Gadget

Fleeing from the war that has raged on the planet Cybertron for millions of years, the heroic Autobots led by Optimus Prime encounter a surprise attack by the evil Decepticons led by Megatron. The ensuing melee aboard the Autobot ship ends when the ship crashes on a volcano. Four million years later, an earthquake reactivates the ship`s computer and resurrects both the Autobots and Decepticons, resuming the great war of the Transformers. 
(Source: AniDB)

Harald Maxmillian Stoltenberg is a Norwegian actor, scriptwriter and children's book author. He was born in Oslo, but grew up in Fetsund. Some of his more famous books are Hester danser ikke ballett, Sverre Skrot and Ingenting, scripts for a number of radio plays and numerous Norwegian children's TV-shows. Most notably the NRK series Uhu.

Stoltenberg is the twin of comedian Robert Stoltenberg and has worked a lot with his brother.

Lars Gunnar Birger Ernblad was a Swedish voice actor and translator. 

Headmasters starts with Galvatron leading a new batch of Destrons to wage war on Seibertron, the Destron Headmasters. The Cybertrons are rescued by the arrival of the Cybertron Headmasters, led by Fortress (Cerebros, the head of Fortress Maximus). It is revealed that Fortress left Seibertron millions of years ago in search of energy, and have finally managed to come home. He explains that the Headmasters are from a planet called Master; the human-sized robots who live there built themselves Transformers-sized bodies. They can then transform themselves into the heads of the robots, and have now joined the Cybertron-Destron war.
 
(Source: Anime News Network)

A manga about the light-hearted misadventures of the Autobots and Decepticons in a setting strongly resembling the original Generation 1 cartoon for a young audience while also promoting various exclusives aimed at older collectors. The web comic additionally inserts character profiles calling out the specific toy being advertised in each issue. 
 
(Source: TFwiki, edited)

After being warped from their universe to that of Mazinger, the Transformers join the fight between Mazinger Z and Dr. Hell's army of mechanical beasts. 

A crossover between Mazinger Z and the Transformers series, with each chapter drawn by a different artist.

Near the end of the 20th century, the Transformers form an alliance with the humans. Together they start to develop a large transportation gate named "Trigger" as a symbol of amicability. However, the Decepticons have their eyes on the gate, and so does somebody else. 
(Source: Transformers Wiki)

Starting off as 4koma and published online to promote the titular Transformers Legends toyline, with special Bonus Edition (出張版 Shutchōban) chapters of the comic packed with the toys themselves, it Initially showcased the misadventures of the Beast Wars cast re-imagined as adult Transformers fans, before eventually taking a more story-driven approach and attempting to connect all the entries of the Japanese Generation 1 anime and manga continuity into one storyline. 

Heavily marketed towards adult collectors and otaku in the face of the brand's dwindling popularity with children after TakaraTomy's largely unsuccessful first attempt in the mid-2000s, it attempted to change the image of the Transformers franchise, with much more "adult", often ecchi-filled humour and numerous references to fan culture.
 
Ulltimately concluded when TakaraTomy began a brand unification with Hasbro starting with Power of the Primes, deciding to mainly sell Hasbro toys as is with minimal changes to packaging. It was eventually succeeded by the more action-oriented Generations Selects Special Comic promoting Hasbro and TakaraTomy's joint Generations Selects imprint. (Source: TFwiki, edited)

Tie-in manga for Hasbro and Takara's Kre-O blocks Transformers product line. The story follows various comedic shenanigans involving Transformers Kre-O sets and figurines, at times retelling the events of Transformers Generation 1 anime's episodes.
 
Note: Chapter count includes a prologue chapter and a special chapter included in the product catalog.