Help with designing a foot for The Bullet

[MartinAndersen]

Hi this is a design proposal for my new OB speaker, I have baptised it "The Bullet"

Looks good 🙂

I need some kind of stand for it, and I need the stand to reinforce the baffle. I would love to have a metal frame but I dont have access to work with metal.

I have attached some OB speakers for inspiration, so we can get the ball rolling

Drivers used in The Bullet: 2 x AE L015, 1 x 6 1/2" 1 x scan-speak D2900

 

[GM]

Well, it can't be too massive, rigid, same as any wide BW vibrating 'tool' stand, just a point of diminishing returns, so Portland cement, sterilized sand, lead shot, etc., filled base, baffle, vertical risers...... ditto sonotubes if you prefer round.

Don't know about on your side of the 'pond', but in my locale, marble, slate is inexpensive enough to consider, so are basic cemetery headstones maybe trimmed to fit a base, baffle, vertical risers option?

For something interesting that I've yet to see, make a Birdcage Maserati chassis style bracing/driver mass loading framework out of dowels.

GM

 

[MartinAndersen]

So you want to go heavy, I also have my concerns of having 2 large 15" in a skinny baffle.
I would like to have some sides on it but then it will be a H frame.

I am using 40mm mdf for the baffle.

 

[charlie2]

I used a 40mm kitchen worktop for base for the baffle to sit in used a router for a groove and placed rubber non slip matting in between, and then a peice of wood 4x2" at around 70% degree angle for rear support

it was a mock up not posh but worked

 

[MartinAndersen]

I used a 40mm kitchen worktop for base for the baffle to sit in used a router for a groove and placed rubber non slip matting in between, and then a peice of wood 4x2" at around 70% degree angle for rear support

it was a mock up not posh but worked

Interesting do you have a picture?

 

[GM]

I am using 40mm mdf for the baffle.

It's a beginning, but MDF is more massive than rigid, so to get both low/high enough makes it much thicker than a mass loaded hollow shell. This is my main 'gripe' with OBs as there's no surrounding cab to contribute the requisite rigidity to push its Fs above the woofer's intended BW unless made from stainless steel or similar and/or has a complex bracing superstructure, so easier to push it below it since OBs typically have a much higher LF roll off corner frequency.

From this, if I were to do something similar to your design, I'd form a triangular 'cab' of steel dowels or mass loaded plastic pipes or similar with some diagonal braces to affix the baffle, base and tightly wrap one or more layers of grill cloth around it to both keep the dust out, blend it to the room's color 'mood' and provide a bit of 'vent' 'critical damping' to 'taste'.

Hope my 'colorful' language translates OK [makes any sense] as sometimes I've unintentionally seriously offended a few folks.

GM

 

[MartinAndersen]

To GM post #6

No I am in no way offended, and thanks for you heavy input.

I wish I could put some sides on it, but then I will have a U frame. Wish I had a very large room the I would have made it very wide with some sides, forming a small U

 

[GM]

You're welcome!

Me too, hence the phantom 'box'. 😉 Proven WAF 'seal of approval' also, at least among the ones I came in contact with; ranging from bone fide 'Southern Belles' to down home 'rednecks' to 'white trailer trash'.

GM

 

[eriksquires]

There's a european maker of very expensive open baffles, they had what I thought the sexiest stand.

I forgot if it was iron or wood, but lookint at it from the top, imagine a T shape, with the speakers facing the top of the T, and a single support making up the '|'part of the T. The '|' was cut out for the drivers.

Best,

Erik