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[Bob Faulkner]

Been using 2 x SRX728 subs for several years; have performed excellent!  I'm considering upgrading to the STX828 series (non powered version).  JBL shows the 828 series to handle more power than the 728 series; however, the raw speaker components of the 828 don't appear to be as robust as what is utilized in the 728 series.  The 728 uses the "Differential Drive" speakers, whereas the 828 uses something called "super gap vented".  I can't find much info on the "super gap vented" product.

Are the 828 series as robust as the 728 series?  Does the 828 series actually handle more power?

- The 728's we use are for live sound only (mostly rock shows); each powered with a QSC PLX3602 (bridged - some on the forum don't like these amps for sub duty, but they have performed very well for us).

[Paul G. OBrien]

I can't find much info on the "super gap vented" product.

What was old is new again. SVG drivers are what JBL used in the SR series that predated the SRX7xx series.
http://www.jblpro.com/pages/pub/components/2242.pdf

[Bob Faulkner]

What was old is new again. SVG drivers are what JBL used in the SR series that predated the SRX7xx series.
http://www.jblpro.com/pages/pub/components/2242.pdf

Thanks Paul!

Well... looking at the spec sheet, it shows that speaker as an 800 watt version.  Though, the STX828 (which appears to have the same driver in it as referenced in the spec sheet --http://www.jblpro.com/ProductAttachments/JBL_STX828S.v6.pdf ), shows to be a 2000 watt cabinet (i.e. dual-18 equates to 1000 watts per speaker).  Is there a marketing "glitch" in JBL's info about the cabinet? 

It would be nice to move to a newer cabinet (828 vs 728), but it looks like the power ratings could be the same between the cabinets; if this is the case, might just stay with the 728.

[David Morison]

Thanks Paul!

Well... looking at the spec sheet, it shows that speaker as an 800 watt version.  Though, the STX828 (which appears to have the same driver in it as referenced in the spec sheet --http://www.jblpro.com/ProductAttachments/JBL_STX828S.v6.pdf ), shows to be a 2000 watt cabinet (i.e. dual-18 equates to 1000 watts per speaker).  Is there a marketing "glitch" in JBL's info about the cabinet? 

It would be nice to move to a newer cabinet (828 vs 728), but it looks like the power ratings could be the same between the cabinets; if this is the case, might just stay with the 728.

All else being equal, 1000W vs 800W is only one single dB more, so almost certainly small enough to ignore.
I seem to remember reading somewhere (sorry I can't remember where, might have included a little "reading between the lines") that the 800W spec came from an 8 hour test whereas the 1000W spec came from a 2 hour test, so if that were the case it's simply a case of believing whichever number better matches your likely usage.
That being said, it's still only one single dB, so don't worry about that - other factors like whether your current cabs actually need replaced, or whether you can crossrent one or the other more easily locally if needed will be far more important.

HTH,
David.

[Brad Dillon]

I own 3 STX828S boxes.. I have never owned the SRX 728S subs.. I love my STX 828S subs.. some noticeable differences.. STX are 2000/4000/8000 and SRX are 1600/3200/6400, Not really all that great of a difference.. STX are also heavier.. Mine weigh 180 pounds a piece.. while the SRX are lighter. If I were you I would keep SRX boxes.. only reason I bought STX is because they just discontinued the SRX boxes.. and I wanted some serious subs to accompany my EV QRX tops... I love my STX subs.. they are very loud and go very low.. 

[Brian Jojade]

The power ratings are nearly the same.  1600 watts versus either 1600 or 2000 watts, depending on which spec sheet you decide to look at.  The STX box is 99db 1w/1m vs 98db 1w/1m.  Again, nearly the same.

What I find interesting is that the SRX is -3db at 33hz, and the newer box is -10db at 32hz.  This spec would indicate the ability of the SRX to give a little bit more of the deep low end compared to it's sibling.

The big advantage of the STX is the better handle configuration and truck pack dimensions that make it a bit easier to move around. The difference in weight is about 15 lbs, but for a sub this size, that weight difference is minimal.

Oh, and as far as trusting manufacturer's spec sheets, always take them with a grain of salt.  If you've got the SRX 728 and use the recommended crossover settings, it's not going to work out well for you, I promise.

http://www.jblpro.com/ProductAttachments/JBL.SRX728S[1].pdf

[Bob Leonard]

The deal is just as has been said. everything old is new, or continued. The SVG series drivers have been around for quite some time, but just because they're not a new design doesn't mean they aren't a great design. I used the 2242 as replacement drivers in a pair of Bag End cabinets when the original drivers failed. That's another story for an exclusive club, but the end result are a pair of cabinets the same size and tuned exactly like an SRX-718.

After loading the cabinets I had at first thought I might eventually get rid of them for a pair of 718's, which would match the rest of my cabinets. However, what I found when running the 718 and the 2242 loaded BE was that the 2242 was not only as good in the cabinet as a 2268 was in the 718, but that the 2242 loaded cabinets could produce lower tones while all the time keeping up with the 2268 loaded 718's.

The SVG technology limits power compression to -3db, unlike older model drivers such as the 2241 which has -6db rating.

https://www.jblpro.com/pages/pub/components/2242.pdf


I for one am very fond JBL's SVG technology, would rather use SVG ceramic drivers than neo drivers, and feel sure the SVG drivers being used in the new cabinets are every bit as good as any of the previous line of cabinets using neo. Maybe even better.
 
Below are the drivers I used and replaced. Note the BE driver by Eminence compared to the 2242, which by the way cost me over $1000 ea. when I bought them.


 

[Bob Faulkner]

Thanks all... Great info!

Yes, saw the power differences between them as being negligible, but wasn't sure if that was a sign of perhaps a defect (in the SRX) or a slight improvement in speaker design for the STX.  After reading the posts, it's good to see SVG has been around (and is a proven design). 

I'm very happy with the SRX728 subs and was considering picking up a couple more of them (used), when I decided to look at the STX line as an upgrade (though, "upgrade" may not be the correct term now).  Yep, the weight is a little more, but as was referenced in an earlier post, it too is negligible.

Has anyone replaced a differential drive speaker (in an SRX box) with an SVG speaker (I'm looking in your direction Bob Leonard!)  In lieu of purchasing new cabinets, perhaps a speaker replacement (if the need should arise) would be more cost effective.

Thanks again for all the feedback.

[Bob Leonard]

Bob,
I don't know of anyone who has swapped a 2242 for a 2268, probably because the SVG drivers cost more money. But that doesn't mean it hasn't been done, and I doubt the casual ear would know the difference if it had. I will say, and this is subjective, that I find the SVG drivers to be very "smooth" in response.

[Bob Leonard]

PS - I remember one job about 5BD (5 years before digital) that I unintentionally drove the 2242's much too hard. It was an accident, but all the same they hit Xmax pretty hard and the clank from the copper ring bottoming out scared the shit out of me. That was a 4000 watt mistake to each driver, but they survived without a scratch and work perfectly to this day, 5 years later.

[ProSoundWeb Community]