Need help designing Sub - Need to go down to 17Hz for 'Earthquake' Project

[s162216]

Does box note support slot vents as it only lets me input the diameter of the port, not the dimensions?

Also with the internal volume, should I include the bracing and port as well?

Does it matter about the driver placement options, or should I just ignore them?

Looks like quite a good program, just had a quick play about with it and it seems fairly good.

 

[lsiberian]

Does box note support slot vents as it only lets me input the diameter of the port, not the dimensions?

Also with the internal volume, should I include the bracing and port as well?

Does it matter about the driver placement options, or should I just ignore them?

Looks like quite a good program, just had a quick play about with it and it seems fairly good.

You can subtract the port manually usually.

It estimates the driver volume for you based on the driver size. I just use it for the dimensions and do my bracing and port manually.

For the rockwool I add the thickness to the panel thickness to calculate the internal volume then I change it back to get the right cuts.

I've never use the driver placement part.

It's probably to help with the resonances. which are shown on the bottom ruler like Frequency chart.

 

[s162216]

Just one quick thought - with the port does it have to be above the bottom of the sub?

What I mean is could I run it right against the bottom of the sub so to save material, or does it have to be raised up a few inches??

 

[TLS Guy]

Just one quick thought - with the port does it have to be above the bottom of the sub?

What I mean is could I run it right against the bottom of the sub so to save material, or does it have to be raised up a few inches??

It can go against the bottom and the back. You only need three sides for the port, the other walls will be the bottom and the back.

 

[s162216]

If I angle the port up the back, won't it get blocked by the mineral wool and fibres get blown out of the port?

I have calculated that the bracing volume if the sub is 23" high and 14" wide is about 0.04 cubic feet. (One horizontal piece 4"h x 14"w x 0.75 and one vertical piece 23"h x 4"w x 0.75)

For the port volume, should I just calculate it as if it is straight along the ground as I have been trying to mentally calculate it and I just can't.

I am going to have the sub deeper than it is wide, is that good or bad?

 

[TLS Guy]

If I angle the port up the back, won't it get blocked by the mineral wool and fibres get blown out of the port?

I have calculated that the bracing volume if the sub is 23" high and 14" wide is about 0.04 cubic feet. (One horizontal piece 4"h x 14"w x 0.75 and one vertical piece 23"h x 4"w x 0.75)

For the port volume, should I just calculate it as if it is straight along the ground as I have been trying to mentally calculate it and I just can't.

I am going to have the sub deeper than it is wide, is that good or bad?

Those dimensions are a good idea. Just cut the Rockwool away from the port. Give it good clearance.

You are on target.

We cleared a bunch of trees Friday night for fire prevention. I worked with a crew all yesterday afternoon, and spent today repairing roads and forecourts. with the John Deere Model A and the JD 420. That is why I'm slow getting back to you.

We have had high winds today, and a tree blew down over some power lines on the next but one property, so I have a V4 Wisconsin engine powering the standby generator right under my studio/theater. Last time I checked there were 300 service calls ahead of us. We have been on generator three hours now and it might be all night. So I'm a bit preoccupied.

 

[jamie2112]

If I angle the port up the back, won't it get blocked by the mineral wool and fibres get blown out of the port?

I have calculated that the bracing volume if the sub is 23" high and 14" wide is about 0.04 cubic feet. (One horizontal piece 4"h x 14"w x 0.75 and one vertical piece 23"h x 4"w x 0.75)

For the port volume, should I just calculate it as if it is straight along the ground as I have been trying to mentally calculate it and I just can't.

I am going to have the sub deeper than it is wide, is that good or bad?

I would wrap your wool in burlap and spray glue it.Burlap is cheap and easy.It will ensure you don't blow wool out of your port.......

 

[s162216]

Do you think those braces I mentioned are big enough?

The wood is now way cheaper than I thought now, one sheet (£14) should be enough for the whole thing.

I have also found the driver for £10 less inc P&P.

Now the whole sub should cost roughly £200

 

[s162216]

O.K, I have worked out the volume of the port wood.
Its 0.13 cubic feet when straight (not angled up side), so obviously I have to do some adjustment, but the difference will be so small I will ignore it.

So the total volume now = 2.42 (internal volume needed) + 0.13 (port) + 0.04 (bracing) + 0.2 (mineral wool) = 2.79 cubic feet.

Does that sound about right? Do you think I should round it up to 3 cubic feet?

The weathers so hot here, its hitting 32 degrees Centigrade (89.6 degrees F)

 

[TLS Guy]

O.K, I have worked out the volume of the port wood.
Its 0.13 cubic feet when straight (not angled up side), so obviously I have to do some adjustment, but the difference will be so small I will ignore it.

So the total volume now = 2.42 (internal volume needed) + 0.13 (port) + 0.04 (bracing) + 0.2 (mineral wool) = 2.79 cubic feet.

Does that sound about right? Do you think I should round it up to 3 cubic feet?

The weathers so hot here, its hitting 32 degrees Centigrade (89.6 degrees F)

That sounds right on target. Well done!

 

[s162216]

Thanks for everything, I am going to get the driver in a month or so.
When I have finished the sub, I will post pictures and try it out with the rumble generator.

Might have to find somewhere a bit better than my bedroom though! I already don't think my parents are too keen with the idea of me having a sub,to quote my mum,

We'll have the ceiling lights rattling, things falling off the walls, and christ knows what else!

My rooms right above the sitting room, so I will have to keep it turned down. (When their around...)

I still have some work to do anyway designing the port and getting the depth from Boxnotes now I know the volume.

 

[lsiberian]

The weathers so hot here, its hitting 32 degrees Centigrade (89.6 degrees F)

That's our low temperature here this time of year.

Still that's a hot temp for that far north.

 

[s162216]

They reckon its going to hit 34 degrees tomorrow, schools going to be so hot as only about 3 rooms have air con and the windows are not exactly the biggest either.
In the past few years the summers have been quite cool, this certainly marks a difference! The hotest place I have ever been, is Rodez in France, whilst on a French Exchange. We were told to look around the city and come back after 2 hours. It was 38 degrees and as non of us had been told what we were doing that day, non of us had any water. Slight problem was the shops all shut for lunch, so we could not get anything and there was literally no shade at all. Eventually though we found a vending machine and we must have brought about 8 bottles eventually.

Now thats the sort of heat I don't like, its way way too hot!