DUMBO 1.0.3 for Mac could be downloaded from the developer's website when we last checked. We cannot confirm if there is a free download of this app available.
Please check the Mac app with an antivirus before launch as it is downloaded from the developer's website, and we cannot ensure that it is safe. The following version: 1.0 is the most frequently downloaded one by the program users. This free Mac app was originally created by SI Agency Inc. The application lies within Audio & Video Tools, more precisely Music Production.
From the developer:
DUMBO is an application that is able to hear the outside sounds when you're listening to music through headphones. If you're listening to music in your office or school by Mac or think you can get much more work done when listening to music in the office, but you didn’t notice someone trying to speak to you. DUMBO can help you with that.
You may want to check out more Mac applications, such as CROSS-DJ, Radiologik DJ or AmpliTube Metal, which might be related to DUMBO.