Vocaloid Wiki

Kasane Teto | UTAU Synthesizer V Studio TALQu

Kasane Teto (重音テト) is a Japanese (and later English) UTAU who was originally created as a troll "VOCALOID" by fans. Her surname 重音 (Kasane) literally means "heavy sound" or "overlapped sound;" while these interpretations are widely accepted among fans, TWINDRILL has not released any announcements about the meaning of the name.[3] Her name テト (Teto) comes from Tetopettenson, a parody song of Le Beau Tambour.

Although her voicebank is only for use in UTAU, many people still mistake her for a VOCALOID. Though she had no final voicebank released for the engine, Teto had a private voicebank with Crypton Future Media, Inc. and there were attempts to release her for VOCALOID in collaboration with AH-Software Co. Ltd.. She later was to be released with a speech voicebank for TALQu in January 2022 and an AI voice database for Synthesizer V Studio in April 2023.[4][5]

Her voice provider is Mayo Oyamano.


Following the rising popularity of Hatsune Miku, "Vippers" (Vip News Bulletin@2ch users) schemed a troll "new VOCALOID release" as an April Fool's joke. Sen (線) provided the rough sketch and Nobuyo Oyama, a spoof for Doraemon's former voice actress Nobuyo Oyama, provided the vocal. The Teto project continued after the troll campaign, and her vocal was recorded again for the use on UTAU, which vocal synthesis software was released two months earlier. UTAU and Teto were both unnoticed among VOCALOID composers at first, but during the last half of the year of her release several creators started composing songs for Teto, causing her fame to be established during the following year. The voice provider's name reading was then changed to Mayo Oyamano (小山乃 舞世 Oyamano Mayo) to avoid unnecessary confusion.

Teto was given official acceptance to piapro on April 1, 2010, and to Project DIVA on October 10, 2011.

At one point, Teto was tested in the VOCALOID engine by Wataru Sasaki, but was scrapped due to not meeting expectations.[citation needed] In 2012, Tomohide Ogata from AH-Software Co. Ltd. came into contact with Mayo Oyamano, discussing the idea of turning Teto into a VOCALOID. However, the voice could not be reproduced in a satisfactory manner.[6][7]

Teto was announced to have a TALQu speech voicebank in July 2021, which later released on January 8, 2022.[8] She was also released as an AI voice database for Synthesizer V Studio on April 27, 2023.[9]

Impact on VOCALOID

The first cover song using Teto was created as early as April 6, 2008, and her signature song "耳のあるロボットの唄 (Mimi no Aru Robot no Uta)" was published on June 10 by Mimirobo-P. Since then several creators including Lamaze-P, Telmin and Death Ohagi started to create Teto songs. Some of these early works include "Fake Diva", "Triple Baka", "Kasane Territory", and "Popipo Mk-II".

This trend changed on August 1, 2009, when UTAU was updated and VCV voicebanks became available. Teto's VCV voicebank was released on October 20, 2009 and her singing became more natural than before. This evolution made more DAW users turn their eyes towards Teto. Many Teto songs were posted to Niconico, and Teto and UTAU established a place among VOCALOID.


Since her adoption for Project DIVA in 2011, Teto has had various unusual chances for a non-VOCALOID vocal synthesizer character to appear in media.

Media Appearances

Japanese record label Avex released a CD album containing Teto songs on October 10, 2012.

From April of 2013 to March of 2014 Teto was adopted as an official character for Hokkaido Broadcasting Co., Ltd.

The Kabuki play Kuruwa Kotoba Awase Kagami, where Teto acted as a side character, was performed on April 29, 2017. The story was inspired from "Yoshiwara Lament", one of the most famous songs of Teto.

In the CD album 手塚治虫と冨田勲の音楽を生演奏で, released on September 6, 2017, Teto collaborated with Miku.

In honor of her 10th anniversary, Teto made an appearance in Miku Symphony 2018-2019 and performed 3 of her popular songs.


An official Nendoroid has been made for Teto.

An official figure based on her popular song "Yoshiwara Lament" was made for Teto.


In Maker Hikoushiki Hatsune Mix, Teto makes a cameo appearance in chapter 14, Kagamine Mix.

Video Games

Teto, along with other non-VOCALOID characters, is a playable character in the Project DIVA series.

Product Information

Product Information
  Genre: Pop, Anison  Optimum Range: A#3~E#5  Optimum Tempo: 70~150 BPM
Package details as noted:

Teto is held under license by Team TWINDRILL and usage of her image and voicebank must comply with their licensing agreement. Her initial release is BOUCALOID on April 1, 2008 with triphones on September 17, 2011, and her second release is BOUCALOID APPEND on October 1, 2012.

Vocal traits as noted:

As noted:

  • Kasane Teto has the next banks available for download:
    • Diphone (Original Consonant-Vowel bank from 2008, consistently updated)
    • Triphone (Regular Vowel-Consonant-Vowel bank, consistently updated)
    • Extra (with ending breaths and rolling "r" as found in German and French)
    • Sasayaki (Extra Whisper CV/VCV bank)
    • Rikimi (Extra Growl CV bank)
    • Sakebi (Extra Shout/Power VCV bank)
    • English (CVVC bank, it is recommended to use an external plugin to input lyrics).
    • Jaku (Extra Weak CV/VCV bank)
    • Ejji (Extra EDGE CV/VCV bank with ending breath pack)
    • Nameraka (Extra Smooth VCV bank)
Software issues as noted:
  • Needs a special suffix to get the Extra voicebanks (appends) working (囁 for Whisper, 力 for Growl, 弱 for Weak, ' for Edge, 滑 for Smooth and ↑ for Shout/Power).
  • Western users may need to convert voicebanks to romaji if the computer's region settings are not configured correctly.
  • Users have reported that her English bank has small flaws (such as mistaking si for shi) but gives a decent, Japanese-accented English.

Additional information




She can be downloaded for free from her website. She is also regarded as one of the most used UTAU in Japan, if not the most used.


Since her first voicebank release, Kasane Teto have received a very positive response from the public. Kasane Teto has more than 20.000 videos starring her at Niconico.

  • She is regarded as one of the primary reasons UTAU became popular due to her infamy as a fake and fame as a character. Her fame lead to the raise of the UTAU "Vipperoids".
  • She is recognized as the first UTAU with a recorded voicebank, as Utane Uta's is borrowed from AquesTalk Female-1, which is machine synthesized.
  • Kasane Teto, Momone Momo, and Utane Uta were referred to as the "3 UTAU Girls" as a result of their fame.

She has made guest appearances in official VOCALOID media by Crypton Future Media such as Project Diva. In fact, because of her fame and constant guest appearances alongside VOCALOIDs, she has been often been mistaken as a VOCALOID.

  • She is the first VIPPERloid.
  • She is the first UTAU character to appear in the Project DIVA video games.
  • She is among the rare instances of a non-commercial voicebank who has seen a commercial adaptation and release by an established company.


  1. Q&A 性別がキメラってどういうこと?
    What does "gender: chimera" mean?
  2. Q&A テトは本当に31歳なの?人間に直すと年齢は半分になるの?
    Is Teto really 31 years old? Should her human age be counted by half?
  3. Q&A 重音テト制作時に参加者の一人から提案されて採用された苗字ですが、その由来は不明です。
    (This is) a surname suggested by a vipper (denizen of vip@2ch) and we adopted it, but where this name was from is not clear.
  4. https://twitter.com/twindrill_teto/status/1416739783213142018
  5. https://www.ah-soft.com/press/synth-v/20230403.html
  6. https://www.youtube.com/watch?v=k-tMiZmwLvY
  7. "Synthesizer V AI Kasane Teto Announced by AHS and Twindrill" - a summary and translation of KASANE TETO's debut contents by MARUMAIN
  8. https://twitter.com/twindrill_teto/status/1416739783213142018
  9. https://www.ah-soft.com/press/synth-v/20230403.html

External links

Language Description Site
Japanese Kasane Teto Official website Link
Japanese Kasane Teto Blog Official blog Link
Japanese atWiki Kasane Teto Wiki Link
Japanese @twindrill_teto The official Twitter account for Kasane Teto Link
Japanese TwinDrillTeto Official YouTube channel Link
English UTAU Wiki Kasane Teto page Link
English UTAU Wiki 2.0 Kasane Teto page Link