echo machine
echo machine is an audio effects unit.
In detail
echo machine is an audio effects unit.
Sources
Each source is named with the standing the house places on it, so the evidence can be weighed rather than taken on trust.
reference work · Reputable secondary · Wikipedia
“Echo machine”, English Wikipedia, consulted as further reading
Consult the sourcereference work · Reputable secondary · Wikidata
Wikidata, structured authority record Q649842: echo machine
Consult the source