Yamaha speakers: useful site for specs
http://www.audio-heritage.jp/YAMAHA/speaker/index.html
has, apparently for each of the impressive 86 models shown, a link to a spec sheet, e.g., fot the 500M, to
http://www.audio-heritage.jp/YAMAHA/speaker/ns-500m.html
which, HOWEVER, is in Japanese.But, you can get a (crudely) machine translated version of it at this URL:
http://66.163.168.225/babelfish/translate_url_content?lp=ja_en&trurl=http%3A%2F%2Fwww.audio-heritage.jp%2FYAMAHA%2Fspeaker%2Fns-500m.html&.intl=us
Apparently, for any other speaker on the first page cited above, you can get a translated spec sheet by substituting the appropriate model designation for the string `ns-500m`, which appears near the end of the second URL. NOTE: the model designaton is case sensitive, and in www.audio-heritage.jp's usage apparently must be in lower case, even though, as the spec sheet itself shows, `NS-500M` is more correct.
HOWEVER, you have another problem: the Yamaha speaker page does not show a `NS-75T`, nor does `ns-75t` work as a substitution. (Perhaps a model not offered in Nippon?)
Good Luck and Happy Hunting.
http://www.audio-heritage.jp/YAMAHA/speaker/index.html
has, apparently for each of the impressive 86 models shown, a link to a spec sheet, e.g., fot the 500M, to
http://www.audio-heritage.jp/YAMAHA/speaker/ns-500m.html
which, HOWEVER, is in Japanese.But, you can get a (crudely) machine translated version of it at this URL:
http://66.163.168.225/babelfish/translate_url_content?lp=ja_en&trurl=http%3A%2F%2Fwww.audio-heritage.jp%2FYAMAHA%2Fspeaker%2Fns-500m.html&.intl=us
Apparently, for any other speaker on the first page cited above, you can get a translated spec sheet by substituting the appropriate model designation for the string `ns-500m`, which appears near the end of the second URL. NOTE: the model designaton is case sensitive, and in www.audio-heritage.jp's usage apparently must be in lower case, even though, as the spec sheet itself shows, `NS-500M` is more correct.
HOWEVER, you have another problem: the Yamaha speaker page does not show a `NS-75T`, nor does `ns-75t` work as a substitution. (Perhaps a model not offered in Nippon?)
Good Luck and Happy Hunting.