Dayton HF Sub plan. Please critique.

[hooligan72]

Hello all,

Please take a moment to look over my sub design.

The sub will be 80% HT and 20% music.

I'll be using this sub:

Dayton Audio RSS390HF-4 15" Reference HF Subwoofer 4 Ohm

In a 9 cu ft net vented box

Three 4" vents (could be flared, not sure yet) 24" long

I will attach the PDFs from bassbox pro with the results

Any feedback would be great

Thanks in advance.

[Cokewithlime]

Since you will be using it for some amount of music, I would suggest keep the enclosure tuning about the same as you have in now but use a slightly smaller enclosure (around 6ft^3) which will result in a little higher F3 but a more gentle LF slope that will be more pleasing musically. In addition you should be able to use just 2 - 4" ports and not experience any port compression or "chuffing".

[weltersys]

Originally Posted by hooligan72

Hello all,

Please take a moment to look over my sub design.

The sub will be 80% HT and 20% music.

I'll be using this sub:

Dayton Audio RSS390HF-4 15" Reference HF Subwoofer 4 Ohm

In a 9 cu ft net vented box

Three 4" vents (could be flared, not sure yet) 24" long

I will attach the PDFs from bassbox pro with the results

Any feedback would be great

Thanks in advance.

Design looks good as long as a suitable HP filter is used (around 17 Hz BW 24).
Vent size seems a bit small for full power use.

Flared vents would be prudent for as much displacement as the speaker has.
A "top hat" vent could reduce the length needed for the same tuning, which may reduce the pipe resonance the long small vents will have, which does not show up in bass box 6.

What is the excursion with 500 watts?
What power level does it take to hit the 14mm Xmax?
What is the vent air velocity at 14mm excursion, 18-20 Hz ?
What power will be used with the sub ?

[revboden]

I'd tune it lower (16hz). As it is, you have 20hz 16hz and 12hz tunings using port plugs.

I'd also use three 3" ports 22.5" long. That would give you 16hz 13hz and for music 9.24hz tunings.

[revboden]

in reference to above comment using 200W and 2nd order HP filter at 16hz

[hooligan72]

Thanks for the responses.

Bassbox pro said that three 3" ports would not meet the "minimum port diameter". I would like bery much not to have any chuffing. Is it more wise to model in winisd? I find the program less user friendly, but I do have it and can try it.

As far as going down to 6 cu ft for better music reproduction; would I need to be concerned about losing low end for home theater? This will primarily be used for home theater. Music will likely be during entertaining only and would be at low volume.

[Cokewithlime]

Originally Posted by hooligan72

Thanks for the responses.

Bassbox pro said that three 3" ports would not meet the "minimum port diameter". I would like bery much not to have any chuffing. Is it more wise to model in winisd? I find the program less user friendly, but I do have it and can try it.

As far as going down to 6 cu ft for better music reproduction; would I need to be concerned about losing low end for home theater? This will primarily be used for home theater. Music will likely be during entertaining only and would be at low volume.

If you stay with the monster 11ft^3 you will require three 4" ports to stay under 15 m/s - the other thing you should be aware of with the 11ft^3 enclosure tuned to 16Hz, is that you will be limited, xmax wise, to a max power of 236 watts.

If on the other hand you take my suggestion of using a reasonable size 6ft^3 enclosure tuned to 16Hz you can drive it to 325 Watts without exceeding xmax, will only require two 4" ports to stay under 15 m/s and have a sub that actually will play louder and integrate better with the rest of your speaker systems.

As far as low end extension is concerned the f10 with the 11ft^3 enclosure would be about 12Hz vs the 6ft^3 enclosure having a f10 of 13.5 hz - I really doubt that you would hear or feel any difference - lol

Here is a quick WinISD plot of the 6ft^3(green) vs the 11ft^3(orange)
390HF_6vs11.jpg

[hooligan72]

I see your point. There's only a 2db difference at 20hz. What length 4" ports did you model in that graphic? Were thay flared?

[Cokewithlime]

Originally Posted by hooligan72

I see your point. There's only a 2db difference at 20hz. What length 4" ports did you model in that graphic? Were thay flared?

In the 16Hz tuning of the 6ft^3 enclosure it would require two 4" ports - each 41" long (flared at the outside end is always a good idea).

If it was my build I would think about making a small compromise and move to a 18Hz tuning which would then allow me to use two 4" ports, each 32" long (flared at the outside end is always a good idea) without really affecting the overall performance of the sub. ( fyi - will move the f10 up to about 14Hz)

[revboden]

Originally Posted by hooligan72

Thanks for the responses.

Bassbox pro said that three 3" ports would not meet the "minimum port diameter". I would like bery much not to have any chuffing. Is it more wise to model in winisd? I find the program less user friendly, but I do have it and can try it.

As far as going down to 6 cu ft for better music reproduction; would I need to be concerned about losing low end for home theater? This will primarily be used for home theater. Music will likely be during entertaining only and would be at low volume.

winISD and Bassbox will give you basically the same results. Use what you're happy with. I was using the 9ft^3 size in my mockups. The 3" ports will not exceed 15m/s as you can see in the second plot I uploaded. Unless you regularly listen to movies/music above 105db the port velocity of the ports would be below ~10m/s at 18hz.