Soundstream Exact Series?

I'm willing to bet that sub trickles v-e-r-y slowly out of the PartsExpress inventory.  When you compare dollar-for-dollar to other 12" subs, that's a hefty price to pay.  It doesn't fall into a niche in the market;  too mundane for the younger, too flashy ("EXACT" logo) for the elder groups.  My bet is that PartsExpress expected these to be gone before 2005 and their cost of purchase was too high on these.  I'm the type who will risk the unknown based on my instincts, and my instincts would lead me instead to this Dayton Quatro for considerably less money...which I might be trying out for a deejay setup.

...but I have no input based on actual experience with these Soundstreams...

It looks to me like it's more in line with a Cerwin Vega, which you can get for $50 if you look hard enough.  I'd be willing to wager that if I traded out my budget CW HED sub for this Soundstream (the sealed box size is the same as recommended here) and give it the same 200 watts, the sound wouldn't be any better.  That's just looking at the sub, its description and parameters.  And my HED cost me $40 as an online closeout.

(...5 or 6 years ago is just about like yesterday when you're looking through my aged lenses... ;)

I had 4 10" exact's in 99 with a reference  5.0 and a 2xs soundstream crossover great subs  i had them in 1.25 cubes of air space per sub in a honda CRX 

Don't get me wrong about this...even though my CW cost me only $40 it is a very good sounding subwoofer.  When you model it, it most definitely comes up better in a vented box.  However, just using the manufacturer's suggestion of a small sealed box yields great sub results.  It's not one who will pound you senseless from a half a block away, but it blends seamlessly with the rest of the audio for what can be considered "budget SQ".  So comparing this Soundstream to the CW shouldn't make you flinch.

As far as what I'm looking at...mainly the result of Qes and Qms, which of course is the Qts.  This Soundstream is at .4 which indicates that the suspension will do better with a vented enclosure.  Contrarily, the EBP comes out to 57 which indicates sealed (the EBP is the result of Fs/Qes).  That dichotomy points to the Qms as culprit, which directly indicates (as far as my limited understanding goes) something of a weakness in the mechanical suspension.  I would expect the measurements of the EBP and the Qts to both indicate either sealed or ported...so I believe the Qts should be at somewhat of a higher number.  If it were, it would indicate that the mechanical suspension can keep up with the demands of pounding in a sealed box.

It really should be used as a SQ woofer in a sealed box, not as an SPL woofer in a vented box.  (But look at the manufacturer's suggested box size with the F3 at 50 Hz...not an ideal model of a SQ sub...)  And I don't believe you'll get SQ with that in a vented.  It looks like trouble to model so you'd just follow the manufacturer's recommendation and be done with it.  That's the way my CW looks when modelled...like it should be in a ported.  I know, just with reasoning and using it, that the CW I have would NOT be a performer in that manner.  That's the way this Soundstream looks to me.  That's basically why I am comparing the two...not for the cost at which they can be obtained.

If I've deduced this incorrectly, I'll realize it somewhere down the road...

When we break down our thought processes into words on paper, it can look like time, effort and study went into it.  But in reality it's a momentary judgement.

In making judgements on what you haven't actually heard and used (or know someone who heard and used it), you look at the big picture first:  What category does this speaker fall into?  Who would use it?  What is it's intended target?  What kind of car and driver would it appeal to?  And in this case:  has it been on sale for too long?  Is there a buzz about it, and if not, why?  And if it's packaged goods using paper and rubber in it's compounds, is it aging and losing its value?  At this point you can start to make a judgement on it's relative value.

Those are just some of the quick thoughts I would use to make judgements about the unknowns.  Participating on this car audio forum for the past year and a half tells me a lot about the buzz factor and what speakers are popular and how they are thought of.  The Exact series of Soundstream hasn't been mentioned (enough, at least, to catch my eye).  That's telling to me.  Whereas the other two subs you mentioned are mainstream topics with more ayes than nays to their credit.

I looked at this same Soundstream sub back in early 2004, same ad, same description.  So I know:  it's not selling, it's not popular, it doesn't fit into a market niche, it's not talked about....  What then?  It is a risk.  What do you do with risks?  Take them if they come at a cheap enough price to justify the risk.  Is $140 cheap enough?  No, not in my opinion.

Doing a comparison of T/S test numbers of this sub with the two popular performers won't be the solution here.  The real-world testimonials of users takes precedent over all.  The thought process in making a quick judgement is scant seconds but it takes much longer to write or read about it.  But that's what we all do when it comes to car audio...make judgements on the product and purchase if it fits the intended place in our systems.  So, sorry about not answering your question directly about a technical breakdown of numbers.  But you got a glimpse of the process I used in the post above, so you should be able to do some number crunching on the three subs if that's what you want to do.

Blowntweeters gave a testimonial here, and it was an aye, for these subs.  Perhaps there are others who have heard it and will post their opinions on this sub's performance when they used it.  Then you might be able to make a judgement on its relative value in today's market.