YAPLA - Yet Another Peerless Line Array

[wrankin]

Yeah, I figure that the higher density fillers are going to be the way to go here. The cheap poly-fil just isn't going to cut it. I'll need to go look around for local sources of wool-felt or check if the blue recycled denim insulation can be used instead.

Are your plots for a single driver or for the full array?

 

[wesayso]

I think the recycled denim can do much of what the fiberglass can do. Maybe it's worth it to look for felt too to use in in combination. I got lucky to be able to buy one huge roll of real wool felt.
I still have plenty left over and used in my subwoofer build too. (between layers of fiberglass). From my recent living room renovation I have this new Ecose glass wool, that one is a lot less itchy! It comes in huge thicknesses.

 

[anchorman]

I’m glad one of us is making progress! I got sidetracked with applying for a job and a bunch of these life stuff. Didn’t get the new job, so staying at the old job for now, and will hopefully get back to my speakers soon!

I ended up with a bunch of the high quality fiberglass stuff in the thick dense form factor that is used for sound deadening. 2” thick. Leftover from a demolition job I did a while back at work.

 

[fluid]

Yeah, I figure that the higher density fillers are going to be the way to go here. The cheap poly-fil just isn't going to cut it. I'll need to go look around for local sources of wool-felt or check if the blue recycled denim insulation can be used instead.

Are your plots for a single driver or for the full array?

You can get the automotive style of felt, removalists often use it to wrap furniture too. Works pretty well as far as I can tell.

I found polyfill to be virtually useless as stuffing in an array, but it does vary quite a bit.

I would also suggest not to go too dense on the type of fibreglass used, often the cheapest to buy is better for this purpose. Density tends to increase gas flow resistivity which is the opposite of what you want at least close to the driver.

The denim stuff is good but be careful to have something in front of it behind the driver as it is not a compressed sheet and the fibres could get in the workings of the driver much more easily in a small cabinet space.

On your graph the frequency was shown up to 500Hz which may have been a graph output choice. Make sure to go higher in frequency as you see in wesayo's graphs (mine too) that most of the blips are up there.

My own experiments with this are catalogued here onwards

Full Range TC9 Line Array CNC Cabinet

 

[anchorman]

Just remembered harbor freight moving blankets are possibly filled with felt like material between the thin layers of fabric quilted on the outside.

 

[profiguy]

For a sealed enclosure I would use low to medium density wool on walls and thin layer of dacron poly fill over it. Over damping a cab takes all the "zing" out of the lower midrange and creates a boring sounding speaker IMO. There's a fine line to this and you'll have to follow your instinct as well as taste. I personally prefer aperiodic damping by means of a variovent on larger cabs. For something small and sealed where the driver plays well into midrange (i.e. 2 way or full range) I like to concentrate thicker low density wool around the driver and use thinner layers further from the driver. Open cell urethane foam works well on the walls of ported cabs. I like to use thicker foam closer to the port area without empeding airflow to the port opening, so less midrange from the rear of the driver doesn't spill from the port.

On drivers with the VC gap exposed, you dont want any mineral or fiberglass particles getting into that area. You can wrap the rear baskets with grille cloth if you're concerned about it. A light coating of hair spray over the mineral wool helps keep the loose particles bound to the surface. I used some Peerless NE180s that have the exposed neo motor which I didn't do this with and ended up with a rubbing VC. Luckily I was able to clean it all out using compressed air. Lesson learned...