The simplest and most popular port. Adding a donut ring to the intake cuts down turbulence as air enters the port from inside the box. The front panel is rebated and chamfered to allow flush mounting. Port can be installed after box is finished.

	1 Single flared end - long Joiner One-piece port Plain length of pipe 1 Donut ring

Both ends flanged

Front and internal panels are rebated and chamfered. Flanging the intake is a little more difficult to do but provides a more consistent load on intake and exhaust cycles. According to an AES study, this dramatically reduces port-generated even harmonic distortion

	2 Single flared ends - one long, one short 1 Joiner One-piece port Plain length of pipe Donut ring

Both ends flanged

A one piece port provides the smoothest of airflow and looks great. Inside flare is generally 5mm smaller in radius compared to outside flare. The front panel is rebated only, allowing the port to be inserted after box the box is completed.

	Single flared end Joiner 1 One-piece port Plain length of pipe Donut ring

One end flanged

The easiest solution where box depth is limited. Port can be installed after box is finished.

	1 Single flared end - long Joiner One-piece port 1 Plain length of pipe 1 Donut ring

Both ends flanged

A better solution where box depth is limited. Port can be installed after box is finished.

	2 Single flared ends - one long, one short Joiner One-piece port Plain length of pipe Donut ring

Dimensions of the donut ring

13mm rollover bit used on two layers of 19mm MDF