Which is better for a DBA (Swarm); powered subs or unpowered?

Is it possible to run 4 passive subs off of one amplifier, say like a Crown XLS series? Run in series or parallel? 

cheeg- sorry, my pager battery died-

Starting with $1000, am I better off buying two used powered subs, three less expensive used powered subs, or a subwoofer amp (eg Dayton SA1000) and two (less expensive) used unpowered subs? What is the advantage of having a discrete subwoofer amp?

Either way will work and depending on your situation and deals you might come across which is better could go either way. Either one will allow you to start small and build. So good question.

That said, the Dayton approach has several advantages:

Reliability- powered subs typically use plate amps that are not all that reliable. Dayton and Parts Express are more reliable.

Quality- having the amp separate from the speakers makes it easier for you to select higher quality subs. With powered subs a little bit of each purchase goes into the amp. You’re buying amps over and over again. So you can get a little more speaker for your money this way. Also if you DIY you can get a lot more speaker this way.

Flexibility- The Dayton has just the EQ, level, filter, boost, and phase control that you need. Most powered subs will have these too. But buying on a budget maybe not all or quite as good. With the Dayton no worries. Also with the Dayton when you get more subs you’ll be able to experiment with connecting subs in series or parallel to change the impedance which changes the sound, which turns out to be a pretty good advantage.

Convenience- With the Dayton you set levels all at once. One interconnect. One power cord.

Main thing to keep in mind when going this route is the unbelievable benefits of a DBA really have more to do with the number of subs than anything else. So you will probably get better results faster with 4 cheap subs than a Dayton and one or two better subs. In the long run though as long as you are sure to complete this with 4 (or more- I have 5 and the 5th really did make it better) then I think the Dayton is the way to go.

Maybe even bigger thing to keep in mind is you just can’t imagine how good the bass will be. Its something you have to experience to believe. Maybe not even then. Had mine a year now and it still amazes me.

Oh, and doing one does not rule out the other. You can do both. Have you seen my system?
https://systems.audiogon.com/systems/8367

Great responses -- thank you!
@spenav what is REW?
@spenav and @noble 100 How would you send the wireless signal to the sub? Wouldn't that eliminate the benefit of reducing the main amp's need to drive the lows?
@noble100 I may hit you up for that series/parallel wiring info; is the benefit related to controlling the impedance of the swarm, or something else?
@millercarbon thanks for the details -- you have a beautiful system, but I couldn't tell from the photos if you were using both powered and unpowered. Do you run your powered subs through the sub amp, too? If so, what is the advantage?
@mofojo I'm pretty sure you can run 4 passives off of a Dayton, but I'm not sure about the Crown. Maybe someone else who knows can respond.

Some subs (I think REL is one) allow you to wire them in a way that reduces the burden on the main amp to cover frequencies below a set cutoff, like 80Hz. Does anyone know if that is possible with the Dayton? Finally (thanks for your patience), is it advisable to use all the same brand/model of subs in the swarm, or does it not matter?

@millercarbon thanks for the details -- you have a beautiful system, but I couldn't tell from the photos if you were using both powered and unpowered. Do you run your powered subs through the sub amp, too? If so, what is the advantage?

Look real close at image #9 you will see a dirt cheap POC IC going from the Melody to the Dayton amps. Its fake gold with a spring and white and red o-rings. A real POC. Immediately to the left of it on the Dayton is a clear plastic IC with a silver RCA with 3 black rings, and just below it you can just barely make out the other one with 3 red rings. The signal from the Melody comes into both Dayton amps, then uses the Daytons built-in bypass to connect to the additional Talon Roc powered sub.

So its "through" the Dayton but Daisy-chained not actually running through any amplification, EQ or level circuits. 

Some subs (I think REL is one) allow you to wire them in a way that reduces the burden on the main amp to cover frequencies below a set cutoff, like 80Hz. Does anyone know if that is possible with the Dayton?

This is another one where you'll hear guys who love tech more than music tell you all the wonderful tech reasons to do this. There are wonderful tech sounding reasons for doing all sorts of things that don't really work out well in practice and this is one of them.

The idea is supposed to be that by relieving the amp and speakers of the majority of energy which is bass that you will get improved detail and a greater sense of ease, and on and on, probably cure cancer, almost certainly cure cancer if a REL is in there somewhere. Amazing sub, REL. Don't even need a DBA all you need is a REL. Yeah I am being super sarcastic.

Because, always left out of the equation is the detail you lose running that signal through the crossover circuit, and extra interconnects, and how its all affected by the quality of the power and on and on and on. They conveniently leave all that out.

What they also leave out and this one is even bigger, is the whole reason we're doing DBA is to take advantage of the superiority of having a lot of different bass sources. Of which your two main speakers are two additional sources. So you shoot yourself in the foot with the bass, add extra stuff in the signal path, don't get the improvement they promised, and actually make the bass worse in the process.

I agree with @noble100  that the bass improvement when going from one sub to two is on the order of twice as good.  I stopped at two for now and I am very happy with what I hear but I know the folks with four properly set-up subs mostly report even further improvements.   If you could wait a bit until you can expand your budget the (award winning) swarm system by Audio Kinesis ($3,200 for all) seems bargain priced for what you get and may actually be less expensive than piecing something together and then upgrading.