Reverb, short for reverberation, refers to the acoustical properties of reflected sound in a specific environment. Understanding how a sound source interacts with an interior room is central to creating the sound of a specific type of room. While bar rooms vary in size, they are generally smaller than 75 feet square. They almost always have surfaces made of wood without carpeting or upholstered furniture. These characteristics define the "sound" of a bar and can be recreated using a reverb effects unit or software filter.
A reverb unit can be plugged into the signal path between the source and recording device or exist as a filter or effects option in computer software. Regardless of which device you use, the reverb effects need specific controls to achieve the sound of audio inside a bar or nightclub. You need controls for room size, decay time, early and late reflection times and how much of the effect you want to mix with the original sound (also known as "wet" or "dry"). The combination of these settings will achieve your desired effect.
For this example, we will assume the sound is inside the bar, but the listener is standing just outside the bar. Set the Room Size to 100 feet. Adjust the Delay time (in milliseconds) to 2000. Early Reflections should be set to 100 percent. Set the Late Reflections -- also referred to as "diffusion"- to 20 percent. The effect should dominate the audio mix, so set the effects mix or "wet" control to 80 percent. When you preview the effect, the audio source should sound like what you would expect to hear coming from inside a barroom if you were standing outside the door. Tweak the settings as needed to fine tune the effect. Reducing the room size and early reflections will place you closer to the sound source.
You can dial in a more compelling "sound coming from a bar" effect by recording the chatter of a small crowd and mixing it with the audio source using audio recording software or an audio mixer. If your reverb device includes Hi and Lo cut filters, turn down the filters to further mimic the sound as it projects through a small opening in the door. You even can reproduce the effect of the door opening and closing by making quick adjustments to the volume and filter settings while you record the audio.