A compound horn loads the speaker from both sides, a point source (fullrange) driver in a front waveguide / horn and back loading with a suiting horn as well. Unfortunately, the driver that can handle the 20Hz-20000Hz frequency range in such enclosure is yet to be invented. As with most backloaded horns the compound horn design suffers from frequency overlapping which results in dips and spikes in the response. Linear frequency response is not possible with backloaded or compound horn designs however the speakers built this way couple exceptionally with the room, hence the natural and favorable sounding construction. There is also a certain element of pureness while driving a set of point source fullrange speakers in a compound enclosure with a stereo tube amp.