I see that there are many "mirror only" and "stream only" items from BBC and VOA. These types of audio items are considered collection names in the metadata. I didn't spend loads of time on this, so there surely could be other collection types that don't have downloadable files.
While I don't know exactly what you are searching for or how you are searching, my instinct here would be to try the advanced search (https://archive.org/advancedsearch.php), and use Boolean operators to exclude (at least) these two collection types; also limit to media type: audio along with whatever keywords you are using.
Internet Archive: Search Engine<https://archive.org/advancedsearch.php>
Notes. You can try constructing a search query and hitting "Search" in the top "Advanced Search" section and then coming "back" to this section to copy that query into the "Query:" box.
Here is how a sample search string using Boolean operators with (random) keyword "lost" would look, though the advanced search form on the Archive site is simpler to use:
(lost) AND mediatype:(audio) AND -collection:(podcasts_mirror) AND -collection:(stream_only)
Hope this helps, if you haven't already gone this route.
From: Association for Recorded Sound Discussion List <[log in to unmask]> on behalf of CJB <[log in to unmask]>
Sent: Tuesday, September 25, 2018 8:24:25 AM
To: [log in to unmask]
Subject: [ARSCLIST] Internet Archive Search Results
Recently we've been using the Internet Archive to search for 'lost' or
rare radio recordings. We have now discovered that the BBC, VOA, and
numerous other radio stations have uploaded thousands if not millions
of recordings which are 'padlocked' that are unavailable for
After a key word search results are displayed as audio wave files
implying that they are available to listen to. However these are
always 'locked' from both playing and downloading.
This situation has become a major irritant in that search results are
now being swamped by these unavailable listings and in fact - for us -
are rendering Archive.org completely unusable.
Does anyone know what's going on? And better how to filter out these