Pondering a DIY sub...

Early B.

I'm considering a DIY passive sub with a 15" driver. I'm looking at the Atlas 15" if they still have them in stock. Any ideas for an enclosure? Schematics? Web links? I'd like to do a box-type sub 'cause it's gotta pass the WAF.

I'm also thinking about getting a monoblock amp instead of a plate amp. Looking for higher quality and possibly a better sound, so I was thinking a used Outlaw or something like that. At least 150 wpc @ 8 ohms (should be plenty once converted to 4 ohms). Budget is around $200 for the amp. Any ideas?

I'm assuming I can use my receiver's crossover and volume configurations. Any other issues I need to be aware of?

Thanks.

tryrrthg

The Atlas 15 will have really hard time passing the WAF if you plan on going with a ported sub. The box will be HUGE! I'm helping gmorris design his atlas 15 sonosub and it will be around 9 cubic feet. His 20" diameter sonotube will stand about 5 feet tall. You'll almost have to build a sealed sub if you plan on getting wife acceptance.

oh, as far as power goes look into pro amps from samson, crown or QSC. they're pretty cheap and plenty of power, you'll probably only need one channel.

gatemplin

I really doubt there are any Atlas drivers left, but the old Tempest enclosure designs should work well.

I'm assuming I can use my receiver's crossover and volume configurations. Any other issues I need to be aware of?

I like to have an amp with variable phase.

I wouldn't really worry about the quality of the plate amps. You're doing well if the driver produces less than 10% distortion at high output, most amps should work no problem. If you want high quality check out the ADA series of amps from www.AdireAudio.com , but they are spendy. For around $200 I would just go with a 250-350w plate amp (Adire, Rythmik, PartsExpress).

Other than Ascendant, check out www.acoustic-visions.com , www.exodusaudio.com , www.diycable.com . There aren't a lot of drivers out right now, but over the next couple of months there will be dozens of brand new high quality drivers.

Also check out http://www.diysubwoofers.org/

Early B.

Thanks, fellas. Just ordered my Atlas 15". Should ship out tomorrow!!!

I think I'll do a sealed sub so I can make the box smaller.

tryrrthg

Originally posted by Early B.
Thanks, fellas. Just ordered my Atlas 15". Should ship out tomorrow!!!

damn it! I was hoping there weren't any more left because I've been fighting myself not to buy one!

Early, congrats on the new driver and keep us posted on your project.

Early B.

I was hoping there weren't any more left because I've been fighting myself not to buy one!

Don't fight it. The price is too good to pass up. Let's do the math:

Bad **** 15" Driver - $105
250 watt plate amp - $125
DIY enclosure - $100
Misc. (paint, polyfill, etc.)- $20

TOTAL: $350

C'mon, this DIY sub will rival anything out there less than $1,200. And it's custom made! Go ahead, take the plunge before they're gone.

tryrrthg

Originally posted by Early B.
Don't fight it. The price is too good to pass up. Let's do the math:

Bad **** 15" Driver - $105
250 watt plate amp - $125
DIY enclosure - $100
Misc. (paint, polyfill, etc.)- $20

TOTAL: $350

C'mon, this DIY sub will rival anything out there less than $1,200. And it's custom made! Go ahead, take the plunge before they're gone.

it would cost me even less, I have a plate amp.

I already have a DIY sub that I made with an old SVS driver. It works well, but obviously I want more.

If I didn't just spend an arm and a leg on a CD player upgrade the driver would already be in my house!

Skynut

Bad **** 15" Driver - $105
250 watt plate amp - $125
DIY enclosure - $100
Misc. (paint, polyfill, etc.)- $20

Ability to knock pictures off the neighbors wall - priceless

Early B.

To keep the enclosure relatively small for the Atlas 15 and eliminate the possibility of port noise, should I consider a passive radiator? If so, which PR should work well for my application? Are they "easy" to build? Keep in mind I don't wanna get too complicated on my first DIY sub project. Thanks.

michael_w

aaa crap I can't hold in the excitement much longer ... you're doin exactly what I have been thinking about constantly for the last day and a half... Looks like I will just have to order one tomorrow (asuming I can get ahold of my moms credit card and they still have some left). It should be a bit of an upgrade from an 8" Athena

tryrrthg

Originally posted by Early B.
To keep the enclosure relatively small for the Atlas 15 and eliminate the possibility of port noise, should I consider a passive radiator? If so, which PR should work well for my application? Are they "easy" to build? Keep in mind I don't wanna get too complicated on my first DIY sub project. Thanks.

You could do that, but I don't know a thing about PR enclosures. I do know that PR's will add a prettey significant cost to your project... I know they're not as easy and I don't think they're reccommended for first time DIY'ers but I'm sure it's not impossible. You just have to weight the PR to the needed weight to tune them. Try the DIY section over at the HT forum. They know their stuff over there!

one other option you could read about over at the HT forum is adding an LT circuit to the sub. It's some kind of EQ built into the amp that boosts the low end response to a sealed sub.

gmorris

Come on tryrrthg, just buy the damn thing already. You know you won't be able to relax until you do.

You can use the other half of the sonotube from my project.

See this link for some nice pictures of the Atlas 15. I ordered mine a week ago. It was shipped on Monday, and in my paws on Wednesday.

labrat

This may be a little like the blind leading the blind but . . .

If you want to design a sub using PR's try using Win.isd. It is free software you can find using google. Set up a sub that looks good using a port and calculate the mass of air in the port. This should give you a pretty good idea of how much the PR should be weighted.

You usually can get by with a smaller enclosure sealed than ported. The LT circuit would do a nice job of extending the frequency curve but you may run out of excursion at low frequencies.

Hope this helps,

Labrat

Early B.

I found a website that details building a front-firing 2"x 2"x 2" (6 cubic feet) enclosure for the Atlas 15 here - http://www.frontiernet.net/~trtinkerer/overview.html

I was wondering if I could modify the enclosure to make it rectangular (18"W x 30"D x 24"H) and downward firing with rear ports. It's still 6 c.f., I think. A rectangle should be more WAF-friendly for my setup. Any problem with doing this?

tryrrthg

Originally posted by Early B.
I found a website that details building a front-firing 2"x 2"x 2" (6 cubic feet) enclosure for the Atlas 15 here - http://www.frontiernet.net/~trtinkerer/overview.html

I was wondering if I could modify the enclosure to make it rectangular (18"W x 30"D x 24"H) and downward firing with rear ports. It's still 6 c.f., I think. A rectangle should be more WAF-friendly for my setup. Any problem with doing this?

You can do that, the driver doesn't care what shape the enclosure is as long as the volume is the same. the difficult thing with an enclosure that size and the Atlas driver is you won't be able to tune it very low because you won't be able to get very long (or enough) ports in that small of an enclosure.

You should download WinISD and play around with it and try modeling a sub. You'll learn a lot just by playing with it.

http://www.linearteam.dk/default.aspx?pageid=winisd

I still think your best bet for WAF and a small enclosure with good extension is a sealed sub with an LT circuit. There is a company that offers plate amps with the LT circuit built in. I think it's http://www.rythmikaudio.com/ check out the LT option.

Early B.

the difficult thing with an enclosure that size and the Atlas driver is you won't be able to tune it very low because you won't be able to get very long (or enough) ports in that small of an enclosure.

If the ports are attached at the rear and running lengthwise, I've got 30" to work with, so the length of the ports shouldn't pose a problem. I plan to use two ports that are 18" long and 4" in diameter. And I've got plenty of room to spare if I want to make them longer.

Also, Chad at Ascendent Audio suggested a ported sub for my application. I have a sealed sub on my 2-channel system (Onix Rocket). When I first got it, I hooked it up to my HT system and it simply wasn't up to the task. However, I like the Rythmik Audio A370 SE amp. I'll probably go with that one. Thanks for the link.

michael_w

just ordered an atlas 15

gatemplin

Dont bother with WinISD. Download Unibox from the FRD. I've used both to design enclosures and Unibox is way more accurate. Also, just off the top of my head, the port volume looks too big for that box. Run the numbers before you build it.

http://www.pvconsultants.com/audio/frdgroup.htm

michael_w

thanks for the link gatemplin and Early I'm in the same situation as you. I have no idea what kind of box to build. I was thinking ported since I don't have to deal with waf. I think I will use an external amp instead of a plate unless I can find one for a reasonable price.

edit: ... found this at PE ... 240 watt plate amp ... uh oh might just have to snatch one of these but I'll keep looking.

gatemplin

Michael,

Check out www.creativesound.ca . It's right in your backyard. I highly recommend him.

michael_w

THANKS!! I can't belive I forgot about CSS .... o man I'm so glad you mentioned that because ordering little things like grill cloth, ports and all that stuff makes it really expensive after shipping and those damn border fees.

better deal on plate amp for me (link) ... cool I might have to pick one of those up.

gatemplin

If you can swing it get the SUB250 amp. Also I can highly recommend www.Solen.ca for parts. Both companies are a pleasure to deal with.

michael_w

My birthday is coming up in about 3 weeks and I was thinking of asking for the sub100 amp but maybe I could throw in some cash and upgrade to the CSS SUB250RF... I'm asuming I should get the one without the bass boost since stuff like that can hurt drivers? O man 360 watts into an Atlas 15 ***drool*** Plus with this model I get a fancy remote control

Polkersince85

If you are looking at a downfiring sub, make sure the sub is designed for it. The Parts Express site at one time had a calculation on whether a sub was suitable for downfiring. Look in their tech pages.

http://www.partsexpress.com/resources/downfire.html

gatemplin

Originally posted by michael_w
My birthday is coming up in about 3 weeks and I was thinking of asking for the sub100 amp but maybe I could throw in some cash and upgrade to the CSS SUB250RF... I'm asuming I should get the one without the bass boost since stuff like that can hurt drivers? O man 360 watts into an Atlas 15 ***drool*** Plus with this model I get a fancy remote control

Yes the flat amp is the one to pick. You can always add an EQ later. I think you are asking for a case of upgrade-itis with the SUB100.

michael_w

I emailed Chad from Ascendant Audio asking for ported box plans so I will post them here when I get them. That link to the box Early provided was built from box plans from Chad. Originally it was a down firing box so I'm curious to get the non modified plans since I'm also thinking of going downfiring instead of front.

btw Early sorry if I'm taking over your thread or anything with my questions....

Early B.

Michael -- thanks for volunteering to post those plans. Chad is supposed to be sending me a copy of those plans, as well, but haven't received them yet. Once he does, I'll do the same.

Just waiting on the driver to arrive. Hopefully, it'll be here in the next couple of days. I'm anxious to get started on this DIY project.

gmorris

Originally posted by Early B.
Just waiting on the driver to arrive. Hopefully, it'll be here in the next couple of days. I'm anxious to get started on this DIY project.

No kidding.... I'm going to try to start cutting the circles for my sonosub tonight. It looks like we're going to have a new forum here at CP, the Atlas 15 forum.

Early B.

My Atlas 15 arrived today. Damn, it's larger than I anticipated. I touched it and I swear that thing growled at me.

Be afraid, be very afraid...

gmorris

Originally posted by Early B.
My Atlas 15 arrived today. Damn, it's larger than I anticipated. I touched it and I swear that thing growled at me.

Be afraid, be very afraid...

I had the same feelings when I first saw mine. That darn thing is huge, way bigger than I thought it'd be. The pictures just don't do it justice. Could you imaging what the Avalanche 18 would look like?

michael_w

I"m still waiting on the conformation email that he said I would get either sunday or monday... I understand they are busy but I'm getting anxious (ordered it on friday)