Design Throries: Bandpass - Dual Chamber/Vented Sealed 4th Order
| Bandpass - Dual Chamber Vented/Sealed 4th Order | |
| Basic Theory | |
| The front and the rear of the driver are housed in their own separate and distinct enclosures. The front of the driver is in a ported enclosure while the rear of the driver is in a sealed enclosure. The driver may be mounted the other way around however as long as one chamber is sealed while the other is vented. The enclosure is designed as a sealed enclosure but with the addition of an acoustic filter (the port) in series with the front of the driver that acts to limit the driver's bandwidth and therefore increase its SPL capabilities within its bandwidth. | |
| Advantages | |
| Very low f3 is possible at the expense of lower efficiency and increased ripple. Extremely high SPL is also possible at the expense of a higher f3 and narrower bandwidth. Less overall driver excursion. More control over cone movement. Bandwidth and efficiency are inversely proportional. | |
| Disadvantages | |
| Combined volume of both chambers results in large overall enclosures. Difficult to design properly. Results may vary substantially due to misalignment of both front and rear chambers as well as tuning frequency. Tend to have "one-note" bass, especially if designed or built poorly. In order to achieve a wide useable bandwidth, there must be some amount of mid-band ripple as well as decreased efficiency. Drivers can be easily blown due to high compression factors because of lowered cone motion and thereby exceeding the thermal limits of the driver before exceeding its mechanical limits. Bandwidth and efficiency are inversely proportional. | |
| Best Applications | |
| Where the large size of enclosure is of little concern. In cars where the design calls for high SPL where the limited bandwidth which results can be increased due to cabin gain. The cabin gain will help achieve a flatter and wider bandwidth across the desired range while maintaining the increased SPL of the enclosure. Very popular in car applications for this reason. | |
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Source: www.danmarx.org
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