First time DIY w/atlas 15" (1 Viewer)

[Will-Layfield]

I have been without a sub ever since I first purchased my HT equipment and I think it is time to finally get a sub. I have decided to build a sub myself with a 15" Atlas in a sealed box run off of a 250 Parts express plate amp. One question I have for you all is what size recommendations do you have for the sealed box? Also when cutting a hole for a plate amp is it hard to seal it up properly? I know a sealed sub has to have no air leaks or else it will sound off so I was wondering how hard it was to reseal around a plate amp and how to do it. I plan on using 3/4" mdf for build material. Also what sort of internal bracing(if any) would I need?

 

[Mattak]

The PE plate amp has a nice foam rubber gasket all the way around the back, so you shouldn't have to use anything to seal it (I would recommend against using any glue/caulking).

See here for manufacturer recommended enclosure sizes.

 

[Adam.Heckman]

Just used a PE250 in my TEMPEST ENDTABLE

As Mattak said, they come with a nice foam gasket that works very well. As for sealing around the driver, I used closed cell foam. Easiest thing to do is go to home depot or an auto parts store and find the strip foam used to seal a cap to a pickup truck bed. It's sticky on one side. Stick that side to the cut in the MDF then just bend it over to the mounting face of the MDF and put your screws straight through it. Works like a charm.

Enjoy!!!

 

[Joey Skinner]

My apologies for this unsolicited advice but for HT you might want to think about a ported enclosure rather than a sealed. The first sub I built was sealed and while it sounded good I soon wanted more. I built a ported sub and was much happier with the performance.

 

[Will-Layfield]

Joey I will take all the advice I can get. I know I could probably get more ouput with a ported box I am a little nervous about it though since this will be my first DIY project. Also if I went the ported route I will need a new game plan because the atlas is not recommended in a ported box. Make some suggestions if you want I don't have a problem with that at all. My main objective is to reach the output of a sub that costs more the the DIY sub and to gain experience while building the sub.

 

[Chad Kuypers]

Will,

The Atlas 15 actually works VERY well in a ported enclosure as well as sealed. We have detailed plans we can supply that take all of the guesswork out of building it too. What kind of enclosure size are you looking to stay within? Let me know.


Chad Kuypers
Ascendant Audio

 

[Will-Layfield]

Chad,
Yeah I would be doing a lot of guesswork so I would love to see your plans. I imagine they are similar to this since the guy was on soundillusions.net, with you giving him input with this website:

http://www.frontiernet.net/~trtinkerer/overview.html
Welcome to Adobe GoLive 6

I think I might just follow that since it is pretty detailed.
If you have anything to add please let me know though. Because the dimensions on that sub sound just about right and everyting is layed out. Is the eggcrate really necessary? Would some other insulator be better than egg crate? Thanks for your time.

 

[Jack Keck]

Will,

I have only built one sub and it is ported. I am a social worker and have been employed by the state of MIchigan for nearly 29 years, so If I do it, it can't be that hard. It's just one more hole to cut.

OK, I suppose you'd have to learn to calculate how long and wide the port needs to be.

The sub came out great. Even with my lack of skill, it's hard to go wrong with the advice you can get here.

 

[Jack Gilvey]

Atlas 15 works for ported, but you need a rather huge box. I'm using a pair in a "rather huge box" myself, but I like the idea of using a single Atlas 15 in about 150l sealed using one of Rythmic Audio's 350w amps with the Linkwitz transform option allowing truly deep extension.

 

[Will-Layfield]

Anyone have any comments about the eggcrate used in the atlas application in the above link? I though stuffing a box was for a sealed subs? Unless the eggcrate serves a diff purpose?

 

[Will-Layfield]

MMMM...atlas 15 should be here next week!!!!

 

[Greg_R]

Will,
There are some who feel that the egg crate foam works just as well as fancy stuffing (in the bass region).

 

[Will-Layfield]

Is it necessary to use in a ported box though?

 

[Will-Layfield]

What is a linkwitz transformer? When I go to DIYaudio more people talk about them over there but I have no idea what it is. I guess I could search or someone could educate me!

 

[Jack Keck]

A Linkwitz trasformer is a circuit that is or can be built into a sub amp to extend the lower end of the bass in a sealed sub. Check out the Rythmik amp site for a better explanation.

Several posters here know more about these that I do and have even built them into their subs. They can give more complete explanations than I can. Perhaps the guy at Ascendant can give you some guidance in this area.

 

[Will-Layfield]

I do not think Chad will be able to get back to me anytime soon with the huge sale going on at AA so I am going to ask you all. I have been doing some modeling with winISD and am not sure how to change or why to change some properties, such as volume under box tab, I don't know how to edit port length either. From the HT boxes I have seen with atlas 15 they have been around 7 to 8 ft^3. Most are using two 4" flare ports. Actually the link I posted in the post a couple above this one shows a pretty good detail of what the box dimensions would be like but should I go ahead and make it an even 24x24x24? And if yes what should the two port lengths be? If anyone should feel the need to run this driver through WinISD to let me know... I think that would be great .

 

[BlakeN]

Will, you never want to make your sub a perfect cube I wish I could explain why but I dont exactly know. I am guessing so you don't accidently cancel some waves out but I have seen it posted several times.

You can't change port length because the length is based on your tuning fequency The port has to be x inches long to = y tuning. You change the tuning or diameter of port not the length. Don't make the port too small or use too few or the air velocity coming out of the port will be audible and "chuff". Too many or too large and you get a very long port.

On thread this Chad talks about using a 9-10^3 box and 4 4" precision ports. I am so tired that there is no way I could model it out right now but if no one has by tomorrow night I will post some numbers.

Thomas if you happen to glance at this what would 4 4" be like compaired to 1 6"? I would think they would have to be very long and what would the advantage be over 3 4"s. I wouldn't think the 15" atlas would move enough air to require this much porting.

I am guessing that 4 4" precision ports with double extensions just happen to hit a frequency thats about right for the box so no cutting of ports is required. In other words ease of construction.

 

[Bryan Michael]

on my old dual 15 syb i had 4 4in flaored portes in the box worked good.

 

[MarkRoberts]

Will,
I spoke with Chad yesterday afternoon. He is supposed to be emailing me the plans today for 2 different ported boxes for the atlas 15". One is 3.2 cu. ft. with one full length 4" precision port tuned to 20hz. The other is a 4 cu. ft. box with 2 3" precision ports full length tuned to 18.5 hz.
The 4 cu. ft. one is 21.5" cubed and the other is 21.5 tall and deep and 15.5" wide. The last dimension might be off I am going on memory so I could be wrong. I will gladly email the plans to you when I get them just let me know. I have 2 15's waiting for a box. Tonight I will be testing a 12" atlas in my 85l box built for a 12" Dayton DVC.
I am pretty anxious to see how it sounds.

 

[Will-Layfield]

Mark that would be great. my e-mail is [email protected] when you get the chance. The only thing is that I have a little more room to work with so I could go larger than a 4 cubic foot box and if I can I would like to take advantage of that. But e-mail the plans nonetheless if you would.