Greg Kolinski

ported Parts Express Titanic sub

Hi guys.I bought one of the Parts Express 15in 1000 w titanic kits a few years ago,and it thumped pretty good for a sealed box design,but after a few years I got bored with it.Rather than invest in a new sub.I called the P.E. tech line ,and had them run the simulattions for how much port tube etc I would nessd to convert over to a vented type.They said it came out to need a port 3in diad by 4in long.So for a cheap test method ,I used some plastic plumbing tube,even had one in the perfect dementions.I installed the port tube,hoping I just didnt ruin the sub LOL.
WOW ,for the money I have in this sub it is a beast.I have had it briefly hit 120dB on some movies!Its not a SVS monster by no means,but for my investment I am really happy!

Greg

The more I learn about this stuff ,the dumber I get

Greg Kolinski

Re: ported Parts Express Titanic sub

with thse old JBL's as front channels,I am not lacking for bass to badly.They are
JBL L150a's,that were completly rebuilt about 5 years ago,anf are in mint condition

The more I learn about this stuff ,the dumber I get

Robert_J

Re: ported Parts Express Titanic sub

You didn't ruin anything but the person that recommended you port it was a moron. A 3" diameter x 4" long port tunes that sub to 35hz. That's way too high for a home theater application. Especially one that has 1,000w on tap. You can easily overdrive the sub with any material below tuning frequency. Modeling it in Unibox, you can overdrive the sub at 24hz at full power. Now, you may never get to full power because port air speed is off the chart. Really. Unibox can't measure it appropriately. I'm surprised it doesn't make fart noises at even low volumes. The Titanic needs at least dual 4" flared ports. And as with all ported subs, the frequency response falls at 18db/octave. So at 20hz, your sub is -22db down from the peak response at 40hz (where there is a 6db hump in the response).

That's right. It has the potential to best an SVS in the correct ported enclosure. The proper ported box would be about 4.5cf tuned to 20hz. I like 120L tuned to 16hz. Now you will lose some top end. So at 40hz, you will only be at 116db (still extremely loud). But at 20hz, you are almost 15db louder than what you have.

-Robert

Greg Kolinski

Re: ported Parts Express Titanic sub

Robert.would I be able to remedy thing s some by making the single port longer?and how much longer would I need.I have had it cranked hard,and noticed no unusual port noises,or signs of driver damage,so I guess I have been lucky.What does my sub model at right now as it is?

Thanks Greg

The more I learn about this stuff ,the dumber I get

Robert_J

Re: ported Parts Express Titanic sub

Current response:


You can make your current port longer, but you will just take up valuable interior air space. If you don't mind having a sub with a pipe sticking out, then make it at least 18" long.

Here's my 120L design.


Notice the hump in the first one and how fast it drops off. The second is smoother down to tuning frequency. At 20hz, you would be 12db louder. That's free bass.

-Robert

Greg Kolinski

Re: ported Parts Express Titanic sub

robert,
so is the first graph what my current set up is.?and the second,the optimal with a longer port tube?
by what I see I have a lot of output around 30-40 hz,but it dies down low, correct?So by adding an 18 tube to my approx 19 in cube,I will get what your second graph shows?Sorry for the dumb questions,I was just following what the Parts Express tech said should work best with the standard 19 in cube the titanic is,
thank

Greg

The more I learn about this stuff ,the dumber I get

Greg Kolinski

Re: ported Parts Express Titanic sub

how long of a tube would I need to use for the stock titanic box, approx 19 cube?would the 18 long tube still be ok in the smaller box?

The more I learn about this stuff ,the dumber I get

Robert_J

Re: ported Parts Express Titanic sub

Correct. 1st graph is current and 2nd is in an optimal box.

If you add a 3" x 18" port to your current setup, then you would get the following. Not bad when you just look at this graph.


But the port air speed is the problem. As you can see, it is well over the recommended limits. But if you don't hear it now, maybe you won't hear it with the new port.


If you do decide to change ports, the new port must have at least 3" of space between the opening and the wall of the box. Anything less and you are impacting the performance. Since you say your box is 19", that means a few inches of port will have to stick out. You can always do something creative like this guy.


I know you were only doing what the PE tech guy said. That guy shouldn't be in tech support. Also, there has been a DIY section here at HTF for years with members including Ron Stimpson (SVS), Tom Vodhanel(SVS), Dan Wiggins (Adire), Chad Kuypers (Ascendant Audio/Epik Subwoofers) and Mark Seaton (Servo Drive/Seaton Sound). That's a LOT of experience with subs. I'd trust these guys over a random tech guy at any place.

-Robert

Greg Kolinski

Re: ported Parts Express Titanic sub

ok Robert.I had enough tube to make a 17 in port,most of it sticks out,not pretty ,but it works for now.One question,will the anti clipping feature of the dayton amp stop the sub from bottoming out.It seems to be deeper now and hav less varience on scened I am familar with,spl stays the same,when before it was bounceing around.

Greg

The more I learn about this stuff ,the dumber I get