do they have bass clarinet, horn or viola in jazz band? my music tech teacher said they do but i am a bit unsure.

Depends what you mean by jazz band - if you mean a typical big band line up then no, bass clarinet (french) horn and viola aren't in the standard line up. If you mean do you find them playing jazz in a band of some sort then bass clarinet is quite common, french horn is not unknown but is quite rare and I've never seen or heard a viola although it wouldn't surprise me if there are some examples.

As TSax says, not traditionally, but I know Horn is used on occasion (I do jazz French Horn solo-ing myself). I've never heard or seen bass clarinet or viola, but given both instruments are supremely cool they should be featured sometimes!

hi!
i don't know much about jazz
but, i'm never heard horn or viola in jazz
bass clarinet maybe..

but, i think it's good to try play jazz in horn or viola..

just try it!

BYE

I've played bass clarinet in a jazz band although it's probably not your most traditional "jazz instrument". There's nothing to stop any instrument really being in a jazz band though.

I can't think of anyone who plays only bass clarinet but there are quite a lot of sax players who double.

Famous jazzers who played bass clarinet include Eric Dolphy and Bennie Maupin.

Currently Julian Siegel, Idris Rahman and Martin Hathaway also regularly play bass clarinet.

Ask Violinia about strings in jazz!

I've played jazz viola though only at home and in an informal workshop setting, but IMO string instruments have great potential for jazz - just look at Grappelli - and there's no reason viola shouldn't be a jazz instrument, BUT, it's not in a typical jazz band set up.