I've been doing it for the past hour or so, just going through and listening to people like Cho'Gath, Kayn, Taric, and the like. And really, I'm loving them. They just seem to have an extra bit of something tossed in.
Cho'Gath himself I absolutely love, and wish his English voice had the same effects that this one provided.
2 things. For the most part the effects are exactly the same, but the key difference is the language.
Let's look at the at the very first phrase in the Japanese:
Omae no tamashii wa kegatte iru...kanpekina
You can break each section into chunks:
O - MA - E NO TA - MA - SHI WA KE - GA - TE - I - RU .................. KA - N - PE - KI - NA
Each syllable is can be broken down bit by bit with a hard consonant sound and light vowel sound for the most part. Because of that, even if you distort the sound a lot, you can still tell what vowel sound you are using. (This doesn't always work well in the case of the last sound where the NA sounds like DA)
In English:
You have stains upon your soul...perfect.
Technically the only words with multiple syllables are upon and perfect, but the sounds are rather long for each and with too much distortion you couldn't tell what the actor is saying.
Hope this helps,
P.S. I don't speak Japanese nor can I write it so I may have butchered the romaji real bad and the quote I chose for the translation may be wrong as well, but they still address the point I was going for.
Synthesizer
Yes we really need audio change option the Japanese dub is better in most cases especially in videogames and League is a lot anime-centered.
Also we need option to buy the other announcers from the store, we are still permastuck with that old voice from 2009
the best japanese voceline is still 
if you know what i mean [slayer-jinx-wink]
