WinISD Charts.

[spellwords]

I have been messing around with WinISD today I only changed a couple of things and this is what it "recommends" (I dont know if it is actually recommending this or it just randomly put something together.

I found a forum that gave me a very rough idea of what charts to look at but I cant tell whats good or whats bad. I hope I have the more necessary charts.

I am planning on using this driver Dayton Audio RSS315HF-4 12" Reference HF Subwoofer 4 Ohm High Fidelity Reference Series

I will most likely be using the bash 300 amp but I might use the Dayton Audio SA240-B.

Box 4.060 ft^3
Tuning freq. 20.16

1 vent
4in diameter
17.04in long
2 flanged ends.

1st: Trans Function Magnitude.
2nd: SPL System input 1.0W??? I noticed that changing this changes the chart so I left it at what it originally had 1.0W.
3rd: Cone excursion.
4th: Impedance.
5th: Rear port air velocity.

[oublie]

The size of the box will be fairly accurate based on the alignment i.e. closed or ported box.

The size of the port always default to 4 inches ideally for a sub the port should be approx half the diameter of the driver but this is where the design skills kick in.

For example if you change the wattage so that the xmax / excursion of the driver is hitting the red max line then you will see that the port velocity has shot through the roof.

In order to stop this and keep the velocity fairly low you need to use a larger diameter port. The problem with this is that it will not just have a larger diameter but the length of the port will increase drastically.

Play around with the numbers and see what you get.

Remember in a ported alignment your excursion will be low around the port tuning or frequency the box is designed for but it will then shoot through the roof.

Also the actual box you build will be a fair bit larger than what winisd shows as this is only showing the amount of air in the box - not the thickness of wood, not the port itself and not any bracing you would but in the box.

I hope this makes sense.

[Mikey p]

The Dayton 240-B has boost at 30 hz, it's best application is for sealed designs. The boost can be defeated by soldering in a couple of different resistors, or get the Dayton 240 with doesn't have any boost.

If this is for home theater then the driver models well in 4 cu.ft. tuned to 21 hz. The Bash 300 with the default hi-pass filter would be ideal.

Which version of WinISD are you using?

[infinia]

don't forget to take the room gain into account. ie the smaller the room, the more lift at lower frequencies. so that max flat Bass Reflex BR tunings have the tendencies to give boomy sound in rooms. maybe OK for some Home Theater sound effects. I tend to go for smaller BR boxes with low Fb tuning, with a sloped LF response somewhere between a sealed design and what you show. Check max SPLs and port velocity by upping power from 1W until voice coil linear (xmax) travel approaches the limit.

[spellwords]

Originally Posted by oublie

The size of the port always default to 4 inches ideally for a sub the port should be approx half the diameter of the driver but this is where the design skills kick in.

For example if you change the wattage so that the xmax / excursion of the driver is hitting the red max line then you will see that the port velocity has shot through the roof.

In order to stop this and keep the velocity fairly low you need to use a larger diameter port. The problem with this is that it will not just have a larger diameter but the length of the port will increase drastically.

I will mess around with the numbers with a 6in port. I have been told many time not go go bellow 4 inches lol.

Here are some numbers if you would like to take a look at it.

At 300W Air port velocity.
69.2 ft/s at 10hz
21.3 ft/s at 18hz
100 ft/s at 22hz

At 300W Cone excursion.
The max mark is at .56in
1.576 in at 10hz
.56in at 17.5hz
and everything else is below .56in

[spellwords]

Originally Posted by Mikey p

The Dayton 240-B has boost at 30 hz, it's best application is for sealed designs. The boost can be defeated by soldering in a couple of different resistors, or get the Dayton 240 with doesn't have any boost.

If this is for home theater then the driver models well in 4 cu.ft. tuned to 21 hz. The Bash 300 with the default hi-pass filter would be ideal.

Which version of WinISD are you using?

I am using the pro/alpha version.

This is for my computer but I also play all my movies through my computer. I would say %75 music %20 movies %5 games. I don't care what the games sound like though.

21hz seems kind of low. Dont most people have it tuned in at 28-33ish?

[spellwords]

Originally Posted by infinia

don't forget to take the room gain into account.

This is something that will have to be ignored. I move more often than I should lol

[Mikey p]

21hz seems kind of low. Dont most people have it tuned in at 28-33ish?

It's not to low for movies, there's lots of content down to 20 hz and lower.

[spellwords]

What is the transfer function magnitude? I changed the port size/length and well...

Air velocity peaks at 66ft/s

Tuning freq 29hz
Vent diameter 6in
Vent length 17in
-3db 24hz

[spellwords]

Originally Posted by Mikey p

It's not to low for movies, there's lots of content down to 20 hz and lower.

Well that's good! How would this effect my music? I have another woofer that is on my current setup and it is staying I believe it is tuned in at 31hz.