Small Sealed Sub Questions

[NateTTU]

Hey guys,

I'm looking to build a sub to finally finish out my theater setup. There atually isn't much around here for sub designs but I know you guys still have some great ideas somewhere that I may have missed.

I currently run the statements for the front, mini statements for the rear, and the center statement up front. I'm looking for something with some seriously low extension to round out the package and can also keep up with the statements output.

I did some research months ago when I first began building my speakers and opted for the TC-2000 sonotube tuned to 14.5 Hz. I actually still have that sub sitting in my closet, never been used. I never got around to actually making the build. However, I'm sitting here now revisiting the whole sub idea and I'm really leaning more towards a small sealed sub. While I may still may go the sonotube route, I would rather not have such a large missle silo in the small room.

Now the plan is to either sell or possibly use the TC2k in a small enclosure. If I need to get a different sub for this build I would like to keep the cost to around $300-350 if possible and if it needs to be an 18'' that will be fine. I would like to tune it to something under 20Hz if possible and give me some good bang down low. I will probably get an ep2500 to power the sub. FWIW, the sub will be placed in a corner of a 12x14ft room.

Does anyone have any recommendations for this criteria?

Thanks,
Nate

[ThomasW]

What size is your TC-2000?

[WillyD]

If you have the 15", you could get a pair of 18" PRs and get some small size+great extension.

[NateTTU]

Sorry, the TC 2k is 15''

[gonar]

the real sub fanatics are over at AVSforum. iirc there are actually a couple active small sealed single driver/2 P.R. threads going on over there right now.

moderators, if I've broken the code by mentioning the other site, please remove my post. no offense meant.

[ThomasW]

the real sub fanatics are over at AVSforum. iirc there are actually a couple active small sealed single driver/2 P.R. threads going on over there right now.

What you've failed to comprehend is this forum was creating subs 7 yrs before there was a DIY section on AVS... So we're not exactly n00bs...

Nate,

You have 2 options, go sealed with an LT circuit or vented using passive radiators

[Mike B]

I have always been an advocate of a sealed sub in the corner of a room. A nice predictable rolloff with max boundry gain. In that small room, it should work well.

[NateTTU]

Sounds great, where do I start?

Seriously though, I really love the DIY community, but I'm not a true member as I don't really have the time or skill to design my own and actually contribute. All I do is take take and take, but I make sure to say thanks in return.

Are there any established designs that I could just copy?

I have no idea what a LT circuit is and as long as its not too much money to invest I would try the passive radiators idea.

Do you think I could get the same kind of extension and ouput from this sub in any other configuration other than the LLT? Even considering both the LT circuit and PR designs?

Nate

[ThomasW]

There are only two ways to get a bunch of low end out of a small box. A Linkwitz transform circuit electronically boost the low end. PRs of course work like ports boosting the frequencies around the Fb

Both LT circuits and PRs increase the price of the sub quite a bit.

Do you want to build the cabinet? If not consider grabbing one of the 3 cu ft boxes from PE, Part Number 302-820. eD also has boxes available..http://www.edesignaudio.com/index.php?cPath=1_27

BTW do you have the T/S parameters for the TC-2000?

[impala454]

Quick question on the eD boxes, would I need their fab rings also? Or are they sturdy enough to just mount the driver straight into the box?

[ThomasW]

A 3/4" MDF ring isn't going to stiffen much of anything.

[gonar]

Thomas, I wasn't implying anything negative, just that over here you tend to have people focused on designing mains for audiophile use, and the other forum is dominated by hardcore sub fanatics.

again, no offense meant.

[Bent]

Thomas has been more involved with subwoofer builds than you give him credit for - check his signature links.

[impala454]

A 3/4" MDF ring isn't going to stiffen much of anything.

Then what would you suggest?

[ThomasW]

IMO at the very least any of these boxes should have the baffle board doubled up. And some side to side/top to bottom bracing couldn't hurt either.

[Mike B]

I think you will do very well with a sealed sub with a -3 dB point around 50-60 Hz. The boundary gain will be going up while the output is going down and you should be pretty happy without any LT circuits.

Sealed subs are the easiest to build too. Hell, you can probably cut your sono sub in half and use that.

[Bent]

'nothing wrong with sealed...

[NateTTU]

In your opinion, do you think there is any better way to utilize this specific driver than in a LLT? It sounds to me that I probably will be giving up some in performance and have a large increase in money to make this project smaller. It won't be the preferred route, but I'm looking for performance first, then cost, then size. The sonotube will fit in the room, but would a 320l sonotube work okay in such a small room? I did consider an IB, but since I live in a neighborhood I thought it best to try to keep the sub inside the room as much as possible.

[ThomasW]

It's up to you to make the decision about what you want to live with. A missle silo or a smaller box?

There's nothing specific to that driver that necessitates using it on a LLT

The only thing a so called LLT provides is extra output in the inaudible section of the passband. This means the room is shaking at a lower frequency that a sub with a higher Fb

You can't use a single 15" driver in an IB. If you have an attic space available a couple Exodus DPL-15"s would make a nice small room IB and won't send sound to the neighbors.

[rob17]

My sub is a tc-2000 15" svc in a sealed enclosure. For the box I made it 20" square I think, Ill have to take measurements when I get home. I made the box out of 3/4" mdf and then added another layer on each of the sides. When I did this I left a 3/4" by 3/4" gap at the edges so I could put in trim and then round it over. So my box is 1.5" thick and the front baffle is 2.25". This thing is real heavy. I have a carvin 600watt pro amp to power it and the bass is insane.

[NateTTU]

Thanks rob, I haven't decided what to do yet, still researching, but since I already have the driver it would be nice to use it. I would love to seem some measurements when you get the time.

Nate

[NateTTU]

BTW do you have the T/S parameters for the TC-2000?

No, at least not the complete ones. I've never used Win ISD before and while this post has a lot of the things I need, I'm still missing the following parameters:

Pe
Le
Xmax
Sd
Z

Again, I should mention that I have never used WinISD so if I don't even need those values then let me know. BTW, I have the SVC version.

Thanks,
Nate

[mike93lx]

That link to eD is for car audio enclosures. they make some very serious home audio sub enclosures that have double and triple baffles with insane bracing. they'll do anything custom that you need, just be prepared to wait a bit.

[brent_s]

No, at least not the complete ones. I've never used Win ISD before and while this post has a lot of the things I need, I'm still missing the following parameters:

Pe
Le
Xmax
Sd
Z

Again, I should mention that I have never used WinISD so if I don't even need those values then let me know. BTW, I have the SVC version.

Thanks,
Nate

You should be able to get everything you need except Xmax here. BTW, with WinISD Pro, you only want to enter Mms, Cms, Sd, BL, Re (Z), and Qms. Read the help files for more details. Let WinISD autocalc the rest of the parms, even though they might not agree with the published specs.

The Wayback Machine will even get you pretty pictures. :drool:

-Brent

[NateTTU]

Its been a while, but I have talked with quite a few other people in other forums and have finally decided to go with a small sealed Maelstrom-X and sell the TC driver. The enclosure was designed by NeoDan and can be found at AVS. The design is just a 24x24x24 cube with the internal volume of the box being roughly 6.23 cubic feet without the driver. I plan on stuffing this to "enlarge" the box volume probably close to 8-8.5 cubic feet. I was told by quite a few people that this driver would do very well with a Linkwitz Transform.

Can anyone help me make one or let me know of something I can buy? I looked at purchasing a MW8 Bassis as it seems to do exactly that, but at $280 unassembled, its a pretty expensive option considering thats the only thing it does. I still need EQ for my room, so maybe if there is a product that can do both, that would be best. Does anyone have any other recommendations?

[BobEllis]

http://behringer.com/FBQ2496/index.cfm?lang=ENG about $150.

[robseyes]

I use the Behringer DEQ2496 it's shelf filters (LT) & it's parametric ability. It works great. It does have a little bit of a learning curve----I think Thomas has a web page devoted to how to use it. :T

[NateTTU]

Whats the main difference between the FBQ and DEQ 2496 besides double the price?

[BobEllis]

The DEQ 2496 is also a crossover, the FBQ just eq

[NateTTU]

Is there anything out there than can EQ my whole theater system and provide me with a LT for some low end control/boost? I looked at the DEQ 2496 but it seems to me that it can only be used on a pair of speakers or in my case just the sub. I have to admit I don't know much about them, but that was my initial impression.

[impala454]

Hey Nate, have you seen the new UMC-1 pre-pro from Emotiva? It will have a built-in room correction EQ (though just HPF/LPF for the sub outputs) and you should be able to get it cheap since you have their current pre-pro. It's due out by ~Dec-Jan

[NateTTU]

Chuck,

Actually I did forget to mention that. I'm planning on upgrading the LMC-1 to the new UMC-1. I didn't think the EQ in that processor would be all that great and wouldn't extend down to 10Hz. If it is a good EQ then I could use that and maybe a BFD to act as strictly a LT. I'll try to see if I can find anymore info about its EQ ability. Thanks for reminding me.

[robseyes]

Whats the main difference between the FBQ and DEQ 2496 besides double the price?

The DEQ employs shelving filters (I don't think the FBQ has these). There are probably other differences ---I just haven't taken the time to figure them out yet. :unsure: