while my velodyne sub is open should i fool with stuffing any sound affecting materials in

scottyboy76

right now it only has about an inch of the very soft white material around the sides and bottom.

the model is a spl series II, its not ported, and has a 1000 watt amp and a 12 inch driver.

Cant think of anything else, just wondering if I should trust that velodyne knew what they were doing and not just cheapening out to save a little moola.

If there should be more packed in there what would be your recommendation?

rooftop59

I am no expert, but considering the volume of the cabinet, and the EQ that is surely in that amp to get that driver to hit into the low 20s in such a tiny cabinet, I would be inclined to leave it alone. One the other hand if you have an spl meter, why not experiment? Fill it a little and listen and measure and see what you think. Worse thing is you take out the extra filling...

polrbehr

Maybe try something once if you are curious, but I wouldn't overthink things.
I hardly believe that poly-fill or whatever they use would be the place where they would skimp to save money?

That is all just my opinion, of course. I've never built a sub or even a bookshelf speaker

scottyboy76

I think you guys are right, I think I'm getting a little too excited, I think velodyne knows better and as polrbehr said, does not seem like the place the would save probably 3 bucks if they filled the whole box up.

Jstas

I wouldn't. Cabinets are designed to a specific internal volume to provide the designed performance.

There's all kinds of stuff that goes in to it. A sealed enclosure usually only gets stuffed when it's slightly too small. Otherwise, if it's too big, you have to take up interior volume with something solid so it's not too boomy and the driver gets a strong enough "air spring" to help control it's movement.

A vented enclosure is usually stuffed to control air flow in the port. If the driver is pushing the air too fast, you can use polyfil to slow it down enough that you don't get port noise.

Otherwise, polyfil just damps things because it slows down air making the enclosure seem bigger than it is.

I've seen it lining enclosures too because it can help eliminate standing waves in the enclosure which mess with air pressures and backwaves on the driver causing distortion and resonances.

It's not something that is as trivial as people think. It can help tame a resonant enclosure and it can quell port noise in a vented enclosure. It can be a good band-aid for an enclosure that is not optimum because of space restrictions like in a car or in a small sub that fits a bedroom, office or apartment. But it can also kill frequency response as well as make a sub too boomy if overdone.

So unless you know the Thiele/Small parameters for the driver and can figure out the interior volume for the enclosure, if the sub wasn't stuffed from the manufacturer, I'd leave it as is. You can actually do damage to the driver and even the amp if you change the enclosure enough that the sub is being over driven or the it can't vent the pole piece because the polyfil is clogging up the vent hole. Then it can overheat and over-draw the amp too.

In something like a small bookshelf speaker, that's not a huge issue but when talking about something like a sub with a larger driver, large magnet and large motor structure being driven by big power, it becomes a concern.

scottyboy76

thank you sir, one more voice from the crowd who know me saying "Don't touch the damn thing".
Without knowing all the technical reasons you brought up, I kinda figured that would be a dumb place to save a few pennys on a sub that originally cost about 1700 bucks.

thanks again

scott