Running BiaB on Windows 10, at the moment recording what comes out of the computer via a USB Sooundblaster Play 3, I think it is. I want to improve the sound quality of both the midi track and the realtracks and presumably need an external box to plug in via USB.
I don't need to record vocals or instruments via this as I do that directly into a Tascam DP24 digital studio, I just want to get the best possible results from the backing tracks BiaB produces.
I can't make head or tail of whether stuff like the Steinberg UR22 or the Focusrite stuff will do this. Can anyone advise? I know there is a thread about this, but it's nearly ten years old.

That depends, many times the MIDI sound issue is best solved elsewhere (the synth being used).

What does this device hook up to, that you actually hear sound from?
That could also be part of the issue.

Realtracks should sound OK through this, unless the headphones/speakers you are using are lacking or mismatched.

Arthur,

Anything "soundblaster" is screaming for an upgrade.

Yes, getting a dedicated audio interface is a good idea. Focusrite is a fine product to use. I've been using the same Focusrite interface for a good 15 years.
Personally, I used to use a digital studio made by Korg very much like the DP24 but when I discovered the quality I could get and the convenience as well, using the focusrite by itself, I switched totally to Cakewalk Sonar DAW software and sold that Korg and never looked back.

To get the best quality from BB/RB I believe you should be working in a DAW and not in the DP24. All the music both audio and midi is handled by the audio interface, in and out of the computer. IN addition, I have discovered, as have others that the tracks created in BB & RB including the real tracks are excellent tracks, but they can stand to be improved. That is done by using plug in VST/FX that is easier done in the DAW. Programs like Ozone that allows you to master with compression, EQ, reverb, and a few other tools that can easily make a huge difference in the quality of the sound of the tracks.

Those DP24 kinds of recorders are handy for throwing some ideas together quickly, but when it comes to getting the best out of them, that, in my opinion, is another thing altogether. Not impossible, just not the best way.... again in my opinion.

IN my current studio, my interface is the DEFAULT sound card for everything. I do not use any sort of mixer board. Everything goes straight into the Focusrite inputs for recording, and the focusrite send the output to my studio monitors. All the studio software is in the box.

An audio interface likely won't make a significant difference to your sound quality, and won't make the type of difference that I think you're talking about. An audio interface will improve the sound over your Soundblaster, but it won't fundamentally change the sound. What kind of changes do you want - better instrument sounds?

What I think you would want to do, for the MIDI tracks at least, is load up your favourite VST instruments in Band-in-a-Box (or export the MIDI to a DAW for that same purpose).

For the Realtracks, you could use EQ or compressor plugins on them to adjust how they sound, but as they're audio recordings you won't be able to use instrument plugins on them.

Yep.... digital is pretty much digital. The big differrence is that the old soundblaster cards used the windows default synth which had some horrible sounding midi patches in it. And the soundblasters are not designed to run a good audio driver and mostly rely on MME as opposed to allowing ASIO to be used. The problems show up when one is trying to run a few softsynths and audio at the same time. The soundcard or interface is like the foundation to the house. Everything working and running properly is based on that foundation.

I like to encourage anyone who is serious about recording music in their computer to make the investment in a solid interface. It makes everything so much easier and enjoyable.