Question for Annunaki/others about PE 15 Titanic Kit

[Khemist1]

Hello
the 15" Titanic kit is supposed to be delivered today (can't wait) and besides spray adhesive for the foam sheets, is there anything else I should need? I read where annunaki had built one for his parents (with the 500 instead of the 1000 watt amp) and was quite pleased with it. Anybody else built one of the these things? Any tips or tricks I should know? Should I use any gasket tape, poly-fill, etc? it's not only my first pseudo-diy, but my first real subwoofer. I decided on it because a) it's on sale for slightly less than the a5 b) i couldn't stand the wait at eD and c) it leaves me with the option of a diy ported box in the future. This forum has been entertaining and incredibly informative. Thanks in advance!

Khemist1

 

[annunaki]

You could have sent me a PM .

You will not need gasket tape. The subwoofer has an integrated rubber gasket. I would suggest a bit of poly-fil. If you have the 3.0 cu.ft. enclosure a single 1lb. or 20 oz. bag is fine for a lightly filled enclosure. Having the 1000W amplifier will be amazing with that sub. I am impressed what it does at my parent's home with only 500 watts. That gives you an extra 3db in output. It should help out on the really low stuff.

Other than that it sounds like you are all set. The poly-fil is an option though. It is not a necessity.

 

[Khemist1]

thank you so much, thought about a pm but figured there might be someone else who also bought the kit.

the minute my wife texts me that it's arrived, I will suddenly come down with a raging sinus infection/ migraine/ food poisioning/ morbid obesity and will probably need to leave work.

will post follow-up impressions/ pics (aka sub porn) if anybody's interested.

peace out

Khemist1

 

[annunaki]

If you wanted to take the time to do it, perhaps a step by step to show members how easy it really is would be neat. Maybe we could make it a sticky if it is done right. Good, detailed pics, and explanations (I can help there if needed).

Once you have it fired up I think you will be really happy with it. The parametric eq and notch filter are a great help with this sub. You can get really low F3 points using them in tandem. Especially considering it is a sealed system.

 

[ErinH]

I would go ahead and throw some polyfill in there to help with low end and get rid of any peaks you may have (ie: boominess ).

Actually, I would do that after letting it play w/o fill for a while. See if the difference is discernible.

There's a site somewhere that lists the effects of quantity of polyfill versus output. I'll see if I can find it.

I'd really like to see how low this sub goes in a sealed enclosure, versus porting and tuning to (say) 25hz.

 

[Khemist1]

that's an addition of poly-fill along with the egg-shell foam on the inner surfaces, right? one of the only complaints I've read on PE's own user review section is that there are no instructions on the placement of the foam. It's like you get a box and some foam sheets. do you put foam on the braces or just the inner periphery?

 

[ErinH]

that's an addition of poly-fill along with the egg-shell foam on the inner surfaces, right? one of the only complaints I've read on PE's own user review section is that there are no instructions on the placement of the foam. It's like you get a box and some foam sheets. do you put foam on the braces or just the inner periphery?

My guess would be against the back wall to trap "noise" or reflection... but I've never done that in my car stereo practice. The only time I've ever used closed cell is for aperiodic enclosures or IB setups.

Anyway... I would do the polyfill in addition to the foam. Essentially, polyfill's substance is denser than air. This "tricks" the subwoofer into "thinking" it's in a bigger box. With exception, usually a larger box will help to flatten out any frequency spikes and also help increase the low end, but that comes with a sacrifice of decreasing FR on the upper end (40hz+).

However, I doubt your ear is going to pick up on those subtle decreases, and you'll probably be willing to sacrifice a little bit of that for low end extension anyway.

Just make sure you watch the sub and listen critically. It is possible to go too large, but in this case, with a kit, I doubt you'll even get that far even if you stuff the crap outta that box.

 

[Swerd]

If you are going to use this subwoofer with a low-pass filter set at 80 Hz or lower, then you really don't need any foam or polyfill stuffing.

This PE cabinet is a large cube with similar dimensions on each side. Standing waves due to internal reflections should be in the 200-400 Hz range. That is well above the frequency of the low-pass filter.

If it bothers you to completely leave out the stuffing, go ahead, put some in. It won't do any harm, and you can't do it wrong.

It is far more important to have strong internal crossbracing to keep the cabinet walls from vibrating.

 

[ErinH]

But, here, the stuffing isn't for standing waves. At least not in the application I'm suggesting.

 

[Swerd]

But, here, the stuffing isn't for standing waves. At least not in the application I'm suggesting.

What is that application?

It's not clear to me what purpose polyfil stuffing or foam lining has other than damping internal cabinet reflections so that they don't interfere with the woofer's front wave.

 

[ErinH]

What is that application?

It's not clear to me what purpose polyfil stuffing or foam lining has other than damping internal cabinet reflections so that they don't interfere with the woofer's front wave.

Once again, coming from car audio world... (but a subwoofer is a subwoofer)

In my experience, using polyfill can help to flatten out the FR of a subwoofer in cases where you have peaks. This really only pertains to ported boxes, and now that I think about it, I don't know that the sub in question comes with a sealed box or ported.

If ported then what I've said in my previous posts is what I am talking about.

If sealed, then disregard everything I've said, and come back when you go ported, lol.

 

[Swerd]

I believe the Titanic III kit comes with a sealed cabinet. I suppose someone could do the experiment and listen to the same subwoofer, stuffed and unstuffed. I'm not sure I could hear any difference. And it would be loads of fun removing and replacing that heavy driver several times while putting in various amounts of polyfill .

 

[ErinH]

I believe the Titanic III kit comes with a sealed cabinet. I suppose someone could do the experiment and listen to the same subwoofer, stuffed and unstuffed. I'm not sure I could hear any difference. And it would be loads of fun removing and replacing that heavy driver several times while putting in various amounts of polyfill .

I don't want you to think I'm arguing. Really, I'm just trying to give my experiences.

Again, the polyfill is essentially acting to make the box "appear" larger so that I can get some more on the low end. In ported enclosures, it really helps to flatten out the response if you don't have a good EQ (and I'm a fan of not using the EQ whenever you can). I've never used it for any purpose other than that.

 

[Swerd]

I agree, and I'm also not trying to argue about this .

My only reason for chiming in is to make sure that newbies who really are interested in building a subwoofer, don't come away with the impression that foam lining or polyfill stuffing is critical in a subwoofer. If it floats your boat to line or fill a subwoofer cabinet, I won't argue.

It can make a difference for a full range speaker cabinet, but that is a whole nuther subject.

 

[gmichael]

Extra foam or not, you're going to love this monster. It only takes a few minutes to put together. I did have to re-tighten my hex nuts a few days later though. It may be worth checking yours after a few days as well to make sure they are still tight. I think the butterfly nuts work their way in deeper if not pulled in all the way the first time.

 

[Khemist1]

wow, what a night....I took as many pictures as I could in my excitement. My dad came over to help me babysit my daughter (8 mo.) His first reaction was "what have you done?" when he saw the two shipping boxes. Stacked on top of each other, they reached above his shoulder. Yes, it is a huge sealed square enclosure, and yes, it could probably use another brace or two. It has one solid slat as a brace. Other than that it appears very well put together. Everything went where it was supposed to with ease. I put a touch of silicone caulk on the feet screws as well as 20 oz of dryer fluffed high loft batting (along with the egg shell foam). The titanic driver is massive, just massive. I have a 15x 15 living room with cathedral ceilings that opens up to the kitchen and dining room. It's a pretty big space. I had no problems pressurizing the air. I need to get a rat shack spl meter today, the para eq looks like it will be handy for adjustments. I can't believe I have to go into to work today. The whole assembly process was so easy it had my technophobic father scratching his chin, contemplating whether to trash his current 10 yr old yamaha sub.

 

[annunaki]

that's an addition of poly-fill along with the egg-shell foam on the inner surfaces, right? one of the only complaints I've read on PE's own user review section is that there are no instructions on the placement of the foam. It's like you get a box and some foam sheets. do you put foam on the braces or just the inner periphery?

They go on the interior walls. Leave the bracing as is. I am not sure how many sheets come with it. In most cases you would do one on the back but not the front, one on the top but not the bottom, and one on the left but not the right.

I would try it without the polyfill to start. Listen and get familiar with it for about a month or 20+hrs. Take notes/measurements with music and movies. whichever comes first. Then add the fill. Do the same thing. Note the changes in sound and measurments (if any).

 

[annunaki]

As swerd has indicated foam and stuffing are not entirely critical. in subwoofer enclosures. However, in this case I would recommend the use of the foam to damp reflections in the enclosure as the panels are fairly large and it is cube. There is only the single horizontal cross brace as well. I have not tested to see if the foam made an audible improvement or not. I know I used a few spare pieces I had from other projects with the one I built for my parents. I did not order the foam with theirs. The spare pieces were place upon the rear of the encl

I also modeled the subwoofer, before it was purchased, in said cabinet and felt that the stuffing may help to lower the F3.