Scaling up a 4inch upper mid and tweet output

[hollowboy]

project kick off and grill question

The only concerns are: with a wide dispersion design I need to pay attention to the room. There is some talk at home about replacing open book shelves with closed cabinets / Baaad idea.

Also for testing speakers with other audience, the best would be to have a grill hide the drivers. I have never used a grill and I am struggling to figure out how to do one. I do not want a wooden frame around helping diffract sound. The best would be some kind of wire frame maybe half inch in front with a stretched cloth?

You could hide your books for aesthetics, and still get an acoustic win - just use louvred (or perforated) doors on the shelves. This would probably make them work better, acoustically, than a standard shelf.

Examples pictured + in link.

You could also try attaching (foam) absorbers to the undersides of things, like the bottoms of tables. I've been in a cafe where they did this, and the difference was very obvious - as soon as I walked in and sat down, I realised echoes were softer than they should be, making conversation easier, so I felt the bottom of the table, and there it was

https://www.timberwood.com.au/products/optiply/product/16/acoustic-plywood.html

I think the wire idea would be fine for a speaker grill. A simpler (but less versatile) option would be to lightly adhere a thin sheet of open cell foam to the baffle (use dots of velcro, or pins in the foam + magnets embedded in the baffles).

Something like this:

https://cannonsound.com.au/products/acoustic-speaker-grille-foam

 

[hollowboy]

However this morning while freezing my b&#% I took measurements and the dips are still there . so back to the drawing board I guess. Not sure if the tweeter horizontal offset is the issue but there is none at higher frequencies where the response climes back up. I have to sleep on it before I try something else. Any ideas?

In VCAD model there is such a dip but lower at ~1kHz so not sure how related to the real issue higher in freq this is. The dip in the model is also persistent and I found no way of affecting it by anything tried so far.

Probably too late to help, but a simple way to work out whether it is the driver-to-baffle-edge relationship to blame: duct tape an extension (a scrap of wood, or sturdy cardboard) to the baffle, and compare the SPL plots before and after.

If the dips improve or shift, then you have found your culprit.

 

[GM]

I have never used a grill and I am struggling to figure out how to do one. I do not want a wooden frame around helping diffract sound. The best would be some kind of wire frame maybe half inch in front with a stretched cloth?

The way I've done it is to use a false baffle, i.e. mount the drivers unrecessed to the box/baffle and make one of the appropriate thickness to 'flush' or slightly bevel a recess for the drivers to tightly stretch the fabric over and install with Velcro tabs.