Abstract: A loudspeaker having a vented enclosure with at least one tuning port includes a fan inside the vented enclosure, which is positioned to produce airflow for cooling the magnetic assembly of the loudspeaker's transducer. Airflow within said vented enclosure is produced such that air within the enclosure is exchanged with outside air through the at least one tuning port. Typically, the vented enclosure will have two tuning ports wherein outside air drawn into the enclosure through one of the tuning ports is circulated out through the other tuning port. Preferably, the outside air drawn in through one tuning port is circulated directly around the transducer magnetic assembly for greatest heat dissipation.

Abstract: A loudspeaker is provided that passively achieves a directional polar response at low frequencies with a high degree of attenuation between the front and the back of the loudspeaker. The loudspeaker 11 has a transducer 13, an enclosure 21 behind the transducer, and port openings 29 in the sidewalls 23 of the enclosure to allow a back-wave produced by the transducer to exit the enclosure and combine with the front wave produced by the transducer. Cancellation behind the loudspeaker at low frequencies is achieved by delaying the back wave with low loss. Low loss delay at low frequencies is achieved by inserting a low-density fibrous fill material 33 in the acoustic chamber 27 formed behind the transducer 13 by the enclosure 21. A fibrous material is selected having a low-pass transfer function and low acoustic loss in its low-frequency pass band.

Abstract: A loudspeaker is provided that passively achieves a directional polar response at low frequencies with a high degree of attenuation between the front and the back of the loudspeaker. The loudspeaker 11 has a transducer 13, an enclosure 21 behind the transducer, and port openings 29 in the sidewalls 23 of the enclosure to allow a back-wave produced by the transducer to exit the enclosure and combine with the front wave produced by the transducer. Cancellation behind the loudspeaker at low frequencies is achieved by delaying the back wave with low loss. Low loss delay at low frequencies is achieved by inserting a low-density fibrous fill material 33 in the acoustic chamber 27 formed behind the transducer 13 by the enclosure 21. A fibrous material is selected having a low-pass transfer function and low acoustic loss in its low-frequency pass band.

Abstract: A loudspeaker having a vented enclosure with at least one tuning port includes a fan inside the vented enclosure, which is positioned to produce airflow for cooling the magnetic assembly of the loudspeaker's transducer. Airflow within said vented enclosure is produced such that air within the enclosure is exchanged with outside air through the at least one tuning port. Typically, the vented enclosure will have two tuning ports wherein outside air drawn into the enclosure through one of the tuning ports is circulated out through the other tuning port. Preferably, the outside air drawn in through one tuning port is circulated directly around the transducer magnetic assembly for greatest heat dissipation.