February 17, 2012, by PSW Staff
When I started working with audio, most companies built their own main and monitor loudspeaker enclosures.
Some did it because it could save them money, but the majority did it because they wanted products that were simply not commercially available, so they had to design and build the systems themselves.
Today there are a multitude of loudspeaker companies making a wide variety of different enclosures – with more designs hitting the market seemingly every week – but there are still a lot of audio folks, including myself, who build many of their own cabinets.
Some of it might involve saving a buck, but I would offer that it’s more because we want a very specific cabinet that is not available, and/or that we just like to design and build things.
Designing a loudspeaker system is a lot easier today than it was in the past. Back then, only a limited number of drivers were available, and there was a lot of trial and error involved in making the boxes. Now we’re blessed with two major improvements.
First, we have computers to help us, and programs like Bass Box Pro and Hornresp make it easy to design and make changes to the design without ever having to cut a single piece of wood. Further, measurement software programs allow us to quickly verify that the finished cabinet has achieved the intended design goals.
The second improvement is that today we have a wide variety of great performing transducers to choose from. In this month’s Real World gear, we look at both woofers and compressions drivers. When choosing these devices for your loudspeaker project, be aware of a few parameters.
The power rating tells us many watts of power a transducer is designed to work with. However, it does not inform us as to how loud a device will go – this is job of the sensitivity specification, which states in decibels (dB) how loud a particular transducer will play given a particular input, usually referenced to 1 watt of input signal measured at 1 meter distance from the driver.
Simply put, the higher the number, the louder the output of the driver. A transducer with a lower wattage rating but a higher sensitivity rating can have a louder output than one with a higher wattage rating but lower sensitivity.
The frequency response is the range that the unit is designed to reproduce, which is relatively self-explanatory. But, as you’ll see in the listings that follow, these do vary between what appear to be similar devices.
For compression drivers, two additional things to look for are throat size and mounting configuration. Drivers normally fall into these throat-size groups: 1-, 1.4- (or 1.5-) and 2-inch. Generally speaking, the larger the throat, the larger the diaphragm and the lower in frequency range the driver can operate in.
Diaphragms can be made of many materials, with aluminum and titanium being the most popular. For mounting to a horn, compression drivers use a variety of bolt hole configurations, and smaller sized drivers can also be designed with threads to screw on to the horn so make sure your driver and horn use the same mounting system or hole pattern.
Enjoy this Real World Gear Tour of cone and compression drivers. Note that we standardized on 15-inch cones, while the driver throat sizes vary.
Craig Leerman is senior contributing editor for Live Sound International and ProSoundWeb, and is the owner of Tech Works, a production company based in Las Vegas.