Ported or Passive Radiator ? (1 Viewer)

[Jack Gilvey]

It takes a lot more power to move the motor structure of a speaker and air (ported), not to mention your 3db down point is usually tuned below the port tuning; whereas, in a sealed box the 3db down point is within the performance spec of the speaker/box combination...

No offense, this is nonsense. Where do you cite evidence for any of this?
Maybe this will help:
Link Removed

 

[Tim Kilbride]

Jack,
Not trying to start an argument here...but some of my credentials to back up my above statements, are as follows:

M.S., Electrical Engineering, Tulane University
**with specialty of electromagnetic theory, Maxwell's equations and electromagnetic waves, Poynting Theorem, microwave techniques and devices, and distributed circuit models.

I worked as an engineering consultant for Klipsch and Associates, Hope, Arkansas from 1989-1992 in the design lab under Paul Klipsch and Tom Gallagher, designing low frequency reproduction units for the KlipschPro KP-600 pro loudspeaker design...and the KlipschPro KP-480, the first pro sub cabinet to use a passive radiator in its design.

I also own a pro sound/lighting production company that was a beta test bed for Eastern Acoustic Works pro sound products (mainly the KF600 series) from 1994-1996.

I am currently the Chief Technical Officer for the Ernest N. Morial Convention Center, New Orleans (4th largest convention facility in the US). Areas of responsibility include design, implementation, and maintenance of all audio, video, telephony, fiber, and lighting inside the facility. I also oversee the day to day operations of the Production Services, MIS, and Telecommunications depts inhouse. I manage 110+ technicians in all areas of concern. My budgets exceed $10 million annually. We are currently designing our 4th expansion of well over 1.5 million square feet, that will utilize some of the latest technologies available (ie voice over ip, fiber based 1000baseT cat6, and fully integrated NEC 2500 co based switch, capable of both copper and fiber, fed by 2 DS3 internet backbones).


I hope this casts any doubts you may have...

Thanks again,
Tim K.

 

[Tom Vodhanel]

Couple of things I would disagree with...FWTW
>>>Jack,
The box is still a sealed enclosure means that there is no exchange of air between the inner volume and the outside world. So the characteristics of a sealed box still apply here.>As for the lower tuning...the PR actually works with the woofer not against it...when the woofer extends outward, so does the PR. It is not a push/pull relationship. So therefore the moving mass is the surface area of woofer 1 plus the surface area of woofer 2. However, you do not have to move two voice coil structures, only one (the PR is passive here). Thus all of your electronic characteristics would be the same for a woofer only box.

 

[Jack Gilvey]

I hope this casts any doubts you may have...

It does, indeed. Thanks.