Multible FR Projects With Reusable PE Cabinets?

[JimOfOakCreek]

I am in the process of studying FR designs. I have my short list of potential projects narrowed down to three.

I do have a question and would appreciate your opinions.

Looking at this hobby in the long run, would it be possible to re-use Parts Express speaker cabinets even though different projects required different volume cabinets?

The PE cabiinets have replaceable front baffles to accomodate using the same cabinet for different projects with different hole layouts. But what about different projects requiring different volumes?

Would it make sense to reuse the same cabinet for a project that required a smaller volume by installing a "false floor" on the inside to reduce the volume? That false floor could be buit up using multiple layers of MDF or even filled with sand below the floor.

[G]

Originally posted by JimOfOakCreek
I am in the process of studying FR designs. I have my short list of potential projects narrowed down to three.

I do have a question and would appreciate your opinions.

Looking at this hobby in the long run, would it be possible to re-use Parts Express speaker cabinets even though different projects required different volume cabinets?

The PE cabiinets have replaceable front baffles to accomodate using the same cabinet for different projects with different hole layouts. But what about different projects requiring different volumes?

Would it make sense to reuse the same cabinet for a project that required a smaller volume by installing a "false floor" on the inside to reduce the volume? That false floor could be buit up using multiple layers of MDF or even filled with sand below the floor.

I don't see why not. It certainly makes good finacial sense.

[Cal Weldon]

Sounds like a good idea to me too. The false floor could be blocks of wood added rather than a floor as such. I have done that numerous occasions when doing test boxes.
I would tend to think that sand would act like insulation and increase the virtual volume rather than decrease it. Just a guess though.

[sreten]

Originally posted by Cal Weldon

I would tend to think that sand would act like insulation and increase
the virtual volume rather than decrease it. Just a guess though.

Hi, It will not. It will work as intended and also damp the cabinet walls, /sreten.

[Cal Weldon]

Interesting. How do you know that?

I can see sand used in constrained layer damping being highly effective but I'm not so sure about a layer in the bottom of the cabinet. Why can the wave not simply pass into the sand as it does with insulation? There is a lot of air within the sand and no rigid barrier to prevent it. Is it that there is a low enough air to sand ratio that it acts more like a solid?

I agree it can have a damping effect on an excited panel but on it's own?

[sreten]

Originally posted by Cal Weldon
Interesting. How do you know that?

I can see sand used in constrained layer damping being highly effective but I'm not so sure about a layer in the bottom of the cabinet. Why can the wave not simply pass into the sand as it does with insulation? There is a lot of air within the sand and no rigid barrier to prevent it. Is it that there is a low enough air to sand ratio that it acts more like a solid?

I agree it can have a damping effect on an excited panel but on it's own?

Hi,

The properties of sand appear to me to be self evident.
Sand does not support airlflow and does effectively behave as
a solid / liquid. Hence the practise of "sandbagging" apertures
for pipes / cables etc. when sound proofing rooms.

Even if it did support airflow, i.e. filling the bottom with small
pebble aggregate, the effective volume of the cabinet would
still be reduced by the solid volume.

It will not damp internal waves in the airspace,
it will damp waves in the structure of the cabinet.

/sreten.

[Cal Weldon]

Thank you.