How does this diy subwoofer look?

[rocko1290]

What do you think about this Dayton Titanic project?

Here are the final specs:

Dayton Titanic MKIII 15"
250w Rhthmik Audio Plate Amp (adjustable rumble filter @ 17Hz)
200 liter ported enclosure tuned to 19Hz

And the graphs:

Green = Dayton Titanic 15", 250w, 200 liter, 19hz tuning
Orange = Dayton DVC 15" (Tempest), 250w, 350 liter, 17.8Hz tuning [my original project]
Red = Dayton DVC 15", 250w, 200 liter, 19hz tuning.







Dayton DVC Xmax - 15.1mm
Dayton Titanic Xmax - 20.5mm.

Is 19Hz a good tuning frequency for the Titanic project??

As you can see, I plugged in my orginal DVC project in WinISD except with a 200L enclosure, and 19Hz tuning frequency (same as the Titanic project), and plotted it alongside my Titanic project. It looks very similar to the Titanic Project. Is there any advantage to using the Titanic over the DVC in 200 liters / 250w? I know the Titanic is built better, but will I get better SQ with the Titanic over the DVC (in 250l w/ 250w)?

Any simple changes to this design that you think will make it better, I will be willing to do. How will this compare to my original 350L Dayton DVC design?

Any other graphs you need, I will be happy to post.

--Thanks

[speekergeek]

I built a sub using the dayton DVC sub here: charting progress on my DIY subwoofer.

my tuning is about 19hz. I used 2 15" PR's and about 3 cubic feet to do it. also a 9db boost centered about the 20 hz mark with some add-in resistance on the amp.
Looks great to me. although I get sick with deep bass it hasn't dissapointed once!

mike

[BassAwdyO]

the orange line looks nice

[Notax]

For 15" Titanic.
Vb=100-120 L, bigger box - group delay is much bigger.
Fb= 24-26 Hz
Dt=110-120mm

Simulation is.....simulation.

[xstephanx]

bigger box = mroe group delay? i believe ive talked to you about this, and it isnt so. properly designed vented subs can have jsut as good GD as sealed. oh, and i would be surpriused if you coudl even ehar a high group delay at 20hz, if you can even hear a 20hz fundamental.


simulation is simulation, but math is math.

[Notax]

Originally posted by xstephanx
bigger box = mroe group delay? i believe ive talked to you about this, and it isnt so. properly designed vented subs can have jsut as good GD as sealed.

Example?

[xstephanx]

example? try VERY low tuned boxes, below FS, and a large box, you can get GD VERY VERY low that way. and where there IS group delay, is below your range of eharing, so does it really matter?

[dscline]

Originally posted by rocko1290
What do you think about this Dayton Titanic project?

No offense, but after your thread at AVS, how many more opinions can you possibly get? You need to just bite the bullet and build it.

[Notax]

Originally posted by xstephanx
example? try VERY low tuned boxes, below FS, and a large box, you can get GD VERY VERY low that way. and where there IS group delay, is below your range of eharing, so does it really matter?

You must be kidding.
Example? Some real bass unit with T/S parameters and your suggestion:
Vb=? box volume, netto
Fb=? tuning freq.
Dt=? tunnel diameter
Lt=? tunnel lenght

[Ron E]

The value of the group delay is meaningless without knowing the frequency at which it occurs and the cutoff frequency of the system.
People have latched on to "group delay" recently IMO because of the proliferation of programs which calculate it and mostly because they don't understand it - it is a magic phrase, somewhat like "phase" that is often mentioned in reviews and websites but not explained.

An EBS type design, where the box is 1.5-2 times the typical size and tuned low enough to provide a shelf in the response, will show a very low group delay. It has a step response which is basically equivalent to a sealed box, but with a LF ringing superimposed. If the tuning is low enough, there is no chance of your hearing the ringing - and it is "virtually" the same as a sealed box, in a sense.