have speaker need to know quality

I picked up some speakers and would like to know how do they perform and the value here ae the specs model: gw-1258     magnet wieght 50oz.        voice coil: 2.5 "alum.    power/max: 290 watts    Req. Res: 37-2.7KHz        SPL(dB) 1W1m:  96  dB    Impedance:  8Ohm                       thanx for the infodave25456

dave wrote: would like to know how do they perform and the value

answer 1) install them, there is no way to tell, but my best bet performance would be less than a set of pyle subs. http://www.partsexpress.com/pe/pshowdetl.cfm?&DID=7&Partnumber=290-382&ctab=2 http://www.itcelectronics.com/pdtl.asp?P=1810 you purchased from what i can tell a set of musical instrument subs, not caraudio. if they are not used, they are probably worth 30$

Drop the T/S parameters into WinISD to get a general idea of whether they will work for your application. You know, parallel those guys to 4-ohms, put them in an appropriate ported enclosure, and you could have some cheap high output sub bass. Who knows how clean they'll be..New Project: 2003 Pathfinder

They won't perform well as subs, as you can see the freq response low is 45 Hz.  And that's probably at -18db.  They are used just as the link /r7 posted says they are.

Yeah.. I'd probably try to resell those babies asap. IF you had a crapload of space you could build a huge ported box that would have reasonable extension, but as Stevdart points out, in most cases the bass simply won't be deep at all. Having said that, if you do decide to use them, build a ported box as freaking large as you can, I'm talking like 5ft^3 per sub, tune it around 35hz, and use a subsonic filter at like 30hz. If you do these three things, you should have some serious SPL around 50-100hz as these things are pretty freaking efficient. ~95db. Who knows how they'll sound, but they could get loud in the right application. Regardless, I'd sell the things, drop some money on a single decent car subwoofer, and save yourself some trouble. If you really just feel like experimenting / dicking around / wasting time and money, etc. you COULD try an isobaric ported enclosure to reduce the volume size.New Project: 2003 Pathfinder

But I insist...don't go to the trouble.  Read this.  (This guy knows a lot about PA systems and guitar speakers, etc.)  "No, a speaker that starts to play at 40hz will not make a good subwoofer because you are missing the human hearing range of 20hz to 39hz in the sound of the speaker."...from the link above.  I can't believe that an enclosure could step in and reproduce those frequencies with any semblance of quality or accuracy.

Wait a second, distortion or linearity of the driver aside, we frequently ask subwoofers to play below their fs. At fs impedance increases dramatically. For a given input, output reduces dramatically at this point. Impedance shifts / lowers / raises depending on the box, correct? If we can push a very efficient pro-driver to -3db at or around 40 I don't see how it is much (any!) worse than many of the car subwoofers available today. (again, distortion aside) In car audio -3db around 35-50hz is generally acceptable because of the significant amount of cabin gain that starts to kick in at that frequency. Shoot, my IDQ10, generally considered a decent car audio subwoofer, is -3db at 45hz in a sealed enclosure, before considering cabin gain. For that matter, even the highly regarded Brahma 12 in a .707 q sealed is -3db at around 40hz. On that note, MOST car subwoofers will display this behavior, the very same behavior that PA guy is talking about. In fact, there aren't many (any!?) subs, period that can play 20-29hz flat unless helped by a ported enclosure. To that extent, I think that PA guy might be somewhat cracked up. Furthermore, there's a whole lot of bass information above 40hz. Shoot, most commercial music on the market doesn't use much decent bass information below 30hz. Many retail bandpass enclosures are designed with higher bass pass regions. They're still considered sub bass. Don't get me wrong, if we're talking about sound quality, we simply don't have an issue here - buy a real woofer. However, distortion aside, I think in the right enclosure those woofers could be OK for in car bass output. ... and I think that PA guy is wrong in many cases. For that matter, there's a bunch of wrong / oversimplied information on that page. Pros, please correct me if I'm totally off base here. New Project: 2003 Pathfinder

http://www.partsexpress.com/pdf/290-382b.pdf is the recommended (by PartsExpress) enclosure for this Goldwood driver......and looking at the graphs, you may have a point, kfr01.  But, man, you wouldn't find me laboring over the workbench for a woofer with a 3.8 mm Xmax unless it was going in a guitar cabinet or something no lower than a midbass cabinet.

I'm not sure I'd place that much stock in xmax, personally. Take your "high excursion car subwoofer" with 2" surrounds and 15mm xmax. Output is partially dependent on displacement. Displacement = xmax * cone area. On our 10" high excursion sub w/ 2" surround you have what, 5" of usable cone diameter? 2.5" radius? Displacement of high excursion sub = pi*r^2 = 19.6 * .59" (xmax) = 11.56in^3 of displacement. Now take this PA 12"... Lets give him 10" of usable diameter. 5" radius. Displacement of PA = 78.5 cone area * .15" xmax = 11.7in^3 of displacement. Uhm... displacement is about the same. Also remember that this PA woofer is 95db+ efficient. That high excursion 10" is at most 90db efficient. You'd almost need to quadruple the amplifier power on that car audio high excrusion sub to reach the same amount of output! Add another 3db because of the second woofer and he's beating the sh*t out of that single car audio 10" in terms of SPL at modest amplifier levels. Anyway... low excursion isn't necessarily bad. The car audio industry is just in this "excursion war." Makes one think excursion is more important than it actually is. There are always tradeoffs... The problem tradeoff here, as I see it, is the need for the giant freaking box size. New Project: 2003 Pathfinder

Just off the top of my head, I'd say a subwoofer billing itself as 'high excursion' would have something around an inch (25 mm) of Xmax.  My cheap CW sub has 17 mm.  Priced comparably to that Goldwood, actually.  And fits in less than a cubic foot box, while playing surprisingly good sub bass.  And has an Fs of 22 Hz.  Point is, why find a way for a pro-sound woofer, meant for an entirely different application, work for car audio...when there is so much else to pick from?  To fill your trunk completely with 200 lbs of MDF just to prove a point?