Quote:
Originally Posted by x3workshop
Correct me if I'm wrong, but efficiency is also directly correlated to cabinet design.
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I'm not going to say you're wrong, but you're not strictly right. An increase in speaker efficiency due to cabinet design is usually bandwidth-limited, tending to increase efficiency from the midbass down. Examples include:
1. Open Baffle - a larger/wider baffle will allow for more efficient bass reproduction. Similarly, a wider baffle on most speakers will lower the baffle step frequency and improve midbass response.
2. Bass Reflex - the port tuning will usually increase bass and midbass response, increasing efficiency in the midbass region.
3. Horn - Horns can increase efficiency over a broader range but still need multiple drivers to achieve a full-bandwidth increase in efficiency. A rear-loaded bass horn will increase bass efficiency while doing little for the midrange and above. Front-loaded horns will also increase the lower frequency range of the driver while having a lesser effect on the upper frequencies.
Putting aside horns for the moment it is reasonably safe to say that a cabinet's contribution to any increase in speaker efficiency tends to be from the lower midrange (~500hz) and down. It is pretty easy to get high efficiency above that frequency from the driver alone, but bringing the bass up to match it is what takes heroics with the cabinet. A great example are the Omega full range drivers. The Alnico driver is rated at 95dB and the RS5 at 94.5dB (oddly specific). One is a 6.5" driver and the other is a 4" driver, rated for similar frequency response and efficiency. However, the 6.5" driver starts falling off below 200hz while the 4" driver starts falling off below 500hz. Everything the manufacturer does is support the lower frequencies to match the midrange efficiency.