This search type is useful to find scores or sound recordings featuring a specific voice, instrument, or combination of voices/instruments. The official USMARCl description of field 048 is given at:
Data in field 048 are from a vocabulary of two-letter codes, often followed by a two-digit number. A list of these codes is available at:
Multiple codes can occur in one 048 field, to cover cases where more than one instrument or ensemble is used. Also, 048 fields themselves may occur multiple times in one record. This would happen if one publication contained multiple compositions which use various performing forces.
Usually, to each two-letter code is appended a two-digit specifier of the number of players or parts. For example, the code for string quartet is sa02 sb01 sc01.
The section labeled "Larger ensembles" is an exception to this rule. A work for orchestra would be labeled oa, not oa01. However, a work for two orchestras should bear the code oa02.
Another exception is the case of multiple-keyboard works. The code "ka02" refers to piano music for two performers at one piano. Two-piano music uses two subfields |a comprising "ka01". Unfortunately, Pilot keyword searching does not enable us to distinguish this coding from those with a single "ka01" (one piano).
To limit a keyword search to this field, precede the search or each part of the search with "048A".
Here is a simple example of such a search. This finds works which use one English horn (in a solo or chamber context). As of April 5, 1999, this search retrieves 57 records.
The following search isolates records with a "word" beginning wf in a field 048 and followed by anything (or by nothing). This would retrieve works scored for one or more English horns (62 records). It will also include any records erroneously containing the code wf with no count suffix at all.
Subfield A of field 048 lists accompanimental or general forces, while subfield B of field denotes one or more soloists. The use of subfield B to distinguish a soloist is a relatively reliable custom for concertos and other cases of a featured solo voice or instrument performing with a large ensemble. It is only sporadic, however, when the large ensemble has been arranged for piano (solo and accompaniment will probably both be in subfield A). For such reasons, an exhaustive search should use a 048A query as well. The search below retrieves records featuring a trumpet soloist.
The results of this search may be the most relevant for your purposes; however, following the following modification of this search will probably yield other results of interest to you.
While this kind of search is especially valuable in fishing out works for unusual instruments or combinations, please bear these caveats in mind: