There are a couple of A'gon members who currently have Ikeda items listed here for sale. You might check with them to see if these items have any company location information on any of the packing materials or manuals.
The number that Raul provided belongs to someone who lives/works in Saitama Prefecture, just north of Tokyo. You also need the country code of 81 before the number but when dialling from outside Japan, you generally leave off the zero at the front of local Japanese area codes (from Norway, you would most likely dial 00-81-48-660-2586 - if that doesn't work, try putting the zero back in between the 81 and the 48). It is the same number as I have found through a separate search for the Ikeda Sound Labs telephone number.
I would recommend writing first and if you receive no response, you might then try calling. Many Japanese people find it much easier to deal with non-Japanese speakers for the first time in writing than on the telephone (I guess anyone would because you can take your time to figure out how to respond). The address for Ikeda Sound Labs Y.K. (the name of his company) is as follows:
Higashi Omiya 2-31-17
Minuma-ku, Saitama-shi 337-0351
Disclaimer: I have no affiliation with Ikeda-san other than the fact that I can google in Japanese :^)
T-Bone's advice is really good.
I have talked to Ikeda san a few times and respect him very much. Bear in mind that he does not speak English. Also, the manuals, etc. are in Japanese (at least the ones I have seen).
Contact me separately. if you wish.... I can give you an email address where the person speaks some English and has some affiliation with Ikeda san. Maybe you can get them to help you.
All the best....mehran