Almighty Subwoofers

By Stig Erik Tangen
01 Jan 1997

Driver selection

The drivers I chose to use in the new subwoofers were, naturally, selected and purchased before the enclosure was designed. The enclosure design was a rather fast process, and enclosure building lasted for only three weeks.

To find the right driver however, was not easy. I made many low-frequency simulations and investigations on normal "hi-fi" drivers, only to conclude that the driver I wanted was nonexisting. No driver, or combination of drivers, could satisfy my requirements.

A friend of mine talked much (he still does) of the SPL performance and power capacity of proffesional drivers, and he must have influenced me to look in the "pro" direction. My friend lent me some JBL and RCF datasheets, and I started to do low frequency simulations. I was really stunned! As an example, the RCF L18P300 18-inch can play 120 dB at 20Hz in a vented box without exeeding Xmax.

The driver I found most favourable for my specific requirements was the JBL 2226G (15-inch). The 2226's distortion measurements is very impressive below 150 Hz, even lower than JBL's 18-inch drivers at the same SPL. The magnet system is carefully designed for low distortion, and the cone is quite good to be paper-based. Thermal power capacity is an incredible 600 W continous pink noise, which will insure no power compression at normal listening levels. The clever construction of the surround actually reduces the moving area of the surround. The aluminium frame is excellent, especially the extremely solid surround. Judged by technical parameters, the JBL 2226 is almost impeccable. It is surprisingly low priced, about half of what a "car-fi" 15-inch woofer costs (JBL 2226 costs NOK 2940 in Norway, equal to about US$ 400).

At first I was very sceptical to how a proffesional woofer would sound. I'd heard PA systems using JBL 15-inch drivers as midranges, and they did not sound much like hi-fi. However, those system used the drivers in a frequency range I would not use them. An other consideration was the quality of the cone. A 335 mm paper cone is not expected to be very stiff, but JBL proved to know what they are doing in this area as well. The Norwegian JBL Pro Audio representative (Lydrommet AS, thanks to them) kindly let me take a closer look at a JBL 2226, and finally I decided to buy two of them. I chose to use the 4 ohm version, as this has the highest voltage sensitivity. If you have an amp with high output voltage capacity, the 8 or 16 ohm version may be your choice.

The following section is stolen from the JBL data sheet (there are no copyright notices on their datasheets!), with some changes applied.

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