Playing With Passives

This Section Last Updated: 5-1-2005

I started playing with some 8" Dayton Passives that were DOTD a while back with the 10" Dayton DVC.

I got the box together and started running some test signals through it just to play around and break in the spiders on the passives.

It is interesting to watch the passives work at different frequencies. One frequency at a certain level, they got into a crazy resonance and it looked wild. Certain frequencies the passives do LOTS of work other frequencies they do very little work.

Basically you are able to watch the air movement that would happen in a standard port.

I am using two Dayton SD215-PR 8" Passive Radiators and a Dayton SD270-8-8 10" Shielded DVC Subwoofer

I measured the box alignment with no stuffing. Note the little glitch at 250Hz

FS: 26hz
QT: .77
Box Tuning: 35Hz (the dip in between the impedance humps)

This next snapshot if with 1lb of Acousta-Stuf. Note the little glitch at 250Hz is gone

FS: 25hz
QT: .74
Box Tuning: 35Hz

I thought i would get crazy and really demonstrate to power of the mass on the passive raditors and their ability to change the box response. I added 54grams of mass to each passive.

FS: 21hz
QT: 1.02
Box Tuning: 28Hz

Here are the T-S numbers for the DVC. This driver is probably the closest numbers i have EVER gotten to published. Either i am measuring better, or Dayton publishes real world numbers.

I even geeked out and loaded the three different PR setups into a flash movie. There are three buttons on the bottom. Click each one to see each box repsonse.


Here is a link to the theoretical design i started with using Bass Box Pro.

Link To PDF

Project Sections:
Playing With Passives
1. Near and Far Measurments

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