Dayton RS100-8 4" Full-Range Driver Can you help with enclosure specs?

[Bengali]

Hi,

I'm looking to try the Dayton Audio RS100-8 4" Reference Full-Range Driver Part #295-352.

If I put them in a cylinder, about 8" tall, how big of a port do I need to get the best low end frequency?
The cylinders will be standing straight up with the speaker pointed upwards.

These will be for a small bedroom surround sound speakers, so if I can get down to 100Hz or if possible lower, that would be great.

The diameter of the cylinder would be around the 4" to fit the driver. I guess I could make the another larger cylinder to increase enclosure volume.
How big would the port size need to be? Should it be small diameter around the cylinder enclosure or a single port?

Thanks for your suggestions.

[Chris Roemer]

At 8" tall, a 4" (PVC) cylinder will only give you a (limiting) volume of 0.05cf.
Using a 6" pipe more than doubles the volume and should yield an F3 near 60Hz using a 1-1/4"id by 6" long port.

It's easy (and fun) to model this using (free) WinISD from linearteam.org . (sgc)

[randyohoh]

A 4" PVC pipe has an actual ID of 4.026 and a 8" length yields an actual volume of .058 cubic foot while a 6" PVC pipe has an actual ID of 6.065 and an 8" length yields a volume of .134 cubic feet. It is important to use the precise measurements especially when using certain pvc tube sizes for ports as the actual dimensions are different enough from the nominal dimensions to in some cases make a significant difference. Ex. 3/4" - 9%, 1" - 5%, 1-1/4" - 9%, 1-1/2" - 7%, 2" - 3%, 2-1/2" - 1%, 3" - 2%, 4" - 1% I believe that designers using nominal pvc sizes in calculations contributes at least somewhat to differences between modeled and actual measurements. I AM NOT an experienced designer / contributor as Chris is but am a retired engineer accustomed to working with precise numbers..

[Bengali]

At 8" tall, a 4" (PVC) cylinder will only give you a (limiting) volume of 0.05cf.
Using a 6" pipe more than doubles the volume and should yield an F3 near 60Hz using a 1-1/4"id by 6" long port.

It's easy (and fun) to model this using (free) WinISD from linearteam.org . (sgc)

Thanks!

I will take a look at that software.

[a4eaudio]

I am finishing up something with that driver right now - 0.15 cf net, tuned to 67.5 Hz, F3 around 57Hz.
I am using the Parts Express 1 3/8" adjustable port (260-388) with the extension tube portion on but NOT extended, but it still adds something like 3/8".
I would think you'll want to line the PVC with some sound deadener (butyl rubber stuff they use for damping in cars) and line with some kind of acoustic foam/insulation/batting/etc.

[Wolf]

Check out the Top Hats by Mike Van Den Broek in the Gallery. Very similar to what you are doing.
Wolf