Jbl prx618s-xlf

C

Chuck Simon

Junior
Jan 19, 2011
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The PRX618s-XLF doesn't get a lot of praise here, but I think that is because not a lot of people here have heard them yet.

I recently bought a second pair and finally got a chance to use them last weekend with a rock band in a nice room. Two XLF's with a bi-amped SRX 722 per side. The two subs stacked gets the 722 nice and high and it sits securely on the recessed top of the 618. It wasn't a big room - the mix position was only about 40 feet from stage. It sounded good! I was hitting 110db peaks at mix position with nice chest-thumping lows, and the red limit lights on the 618's were not close to flashing. In other words, I had more in reserve.

They only weigh about 80 pounds apiece and can be had for slightly over $1000.00 if you look around. I like the idea of adding or subtracting subs as needed without adding amps or re-configuring my current amp racks.

I'm sold!
 
Re: Jbl prx618s-xlf

I don't think no news is bad news, either.

We had a demo of the PRX618S-XLF down at my shop a while back, and it was excellent. I owned four SRX718S back in the day, and this brought back memories of those. They sound very similar, which is to say, really good!

The PRX has some nice features such as both L & R inputs so you can sum to mono and use a single sub, high pass on the link outputs, selectable crossover, etc.

I'm still torn on whether I'm buying the PRX or the VRX sub, though...
 
Re: Jbl prx618s-xlf

Loren Aguey said:
Have you had any issues with thermal shutdowns with this sub like the reports of other cabinets in the PRX line?
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We've been using a pair for drummers who want texas headphones, and have been running them WFO with the clip lights just lighting and they've stayed cool to the touch. Same for the 615m sitting on top
 
Re: Jbl prx618s-xlf

We've been using a pair for drummers who want texas headphones, and have been running them WFO with the clip lights just lighting
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If those drummers aren't deaf by now, they will be!
 
Re: Jbl prx618s-xlf

Silas Pradetto said:
I have never heard of any PRX box having a thermal shutdown. QSC HPR, on the other hand, is a different story.
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A quick google search shows several posts about it and its mentioned in user reviews however maybe they're exaggerated and some of them are DJ forums. Reports were of the top boxes though not the sub. According to the reports it had to do with the lack of fans and the heatsink not being sufficient for cooling.

I caught a set on a PRX rig myself and one of the 12" boxes shutdown while they were running 3 per side. They were not being pushed very hard at all.

Anyway, glad to hear you guys aren't having problems with yours. I'm curious as to why I haven't heard more about the 625. A dual 15 that weighs 60lbs...however this is among the boxes I've read reports of shut downs.
 
Re: Jbl prx618s-xlf

One thing about powered speakers is that damage done on a previous night can often go unheard/noticed especially as the clip lights etc are both out of sight and very basic in the information they give. So next time they're out it shuts down and everyone is complaining, you can shut down any system if you use it way outside it's limits it's just that it seems easier with self powered lower price stuff, which is probably more of a refection on the users than the gear. G
 
Re: Jbl prx618s-xlf

gordon mcgregor said:
One thing about powered speakers is that damage done on a previous night can often go unheard/noticed especially as the clip lights etc are both out of sight and very basic in the information they give. So next time they're out it shuts down and everyone is complaining, you can shut down any system if you use it way outside it's limits it's just that it seems easier with self powered lower price stuff, which is probably more of a refection on the users than the gear. G
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Except well-designed self-powered speakers should be nearly foolproof, while people running passive systems, especially at the 'lounge' level, rarely go through the effort of setting correct limiters. I think powered speakers are always a better idea for people that don't know what they're doing (not saying this about anyone specifically).

In the case of the PRX618S-XLF, the internal amplifier (1000 watt) is barely more than the RMS rating of the woofer (800 watts). So the likelihood of blowing the woofer even without a limiter is pretty minimal unless someone's really abusing it. I know for a fact that JBL has good limiters in there and they should never blow up.
 
Re: Jbl prx618s-xlf

Silas Pradetto said:
In the case of the PRX618S-XLF, the internal amplifier (1000 watt) is barely more than the RMS rating of the woofer (800 watts). So the likelihood of blowing the woofer even without a limiter is pretty minimal unless someone's really abusing it.
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Silas,

Have you been paying attention at all to the discussions on thermal limiting and driver failure?
 
Re: Jbl prx618s-xlf

Bennett Prescott said:
Silas,

Have you been paying attention at all to the discussions on thermal limiting and driver failure?
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Yes, of course. The 2268H(or FF) can handle 800W RMS, and JBL tests their woofers for 100 hours with 6dB crest factor pink noise (peaking at 3200 watts, 800 continuous). So unless someone was playing a pure sine wave (1000W) at full clip, the woofer would be fine. And in that case, I think the amplifier would thermal before the woofer would toast. I owned four SRX718S back in the day and they could pop the breaker on two bridged RMX2450s with never a problem with the woofers. Only time I did cook two 2268s was when I played dance music at clip through an IT8000, with no limiters, for 3 hours. The woofers failed 10 minutes from the end of the show.

And I know that just because the woofer can thermally handle 800W, it doesn't mean that the rating is not already beyond the threshold of diminishing returns. That is, the power compression at 800W may already be higher than the power compression at 400W by an amount greater than the increase in output by doubling the power....so the woofer theoretically could be louder at 400W.

Of course, my assertions here are purely based on my experience with the 2268; if they had to, I'm sure someone could find a way to destroy a woofer in a PRX618S-XLF, just to prove me wrong. As of now, though, I haven't heard of a 2268 failure in a PRX618S-XLF.
 
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Re: Jbl prx618s-xlf

Most of the failures I've seen on lower level powered systems usually involve the amplifier section, the original SRM450s stupid volume control allowed people to put a serious line level into an input stage expecting a mic level cue a very quiet speaker next time as the input stage was blown. As I said there is no complete answer to stopping systems getting blown only different degrees of success. IMO the less buttons etc the safer ie Mr Meyer's and Mr Dravinec's gear though I'll bet someone will break it somehow, the cheaper systems always seem to have unecessary controls on them(added value?) which lead to problems with inexperienced operators who seem to be in the market for these speakers go figure. G
 
Re: Jbl prx618s-xlf

This past weekend I did a show with twelve (yes, 12) PRX618S-XLF subs. They were running with a McCauley Mline rig (6 M90s per side). This was my first time with the McCauley stuff, and it was louder than I expected. Unfortuntely, there are no 'plug and play' tunings for it, so a good part of my time was spent tweaking general settings in a Driverack 4800 to make them sound good. However, I did get to mess with the subs. I processed the 12 subs with my Driverack 4820 with 3 delay taps. The center four subs were not delayed, the two on either side of those got about 1ms, and the two on either side of those two got 2ms. This still gave me a pretty tight pattern, but it was far better than before.

So, how did it sound? Fantastic, actually. I was thinking that the 12 subs weren't going to be nearly enough (really, that's only equivalent to 3 double 18s per side), but it ended up being more than plenty. I used the integrated crossover in the subs, which has a LR lowpass at 90Hz falling off at 48dB/octave. All the subs needed was a small cut at 90Hz or so, and the rest was razor flat down to 40Hz. Playing music the subs sounded exactly like I want my subs to sound...punchy, deep, unstrained, no port chuffing or other odd noises.

Though it was a bit odd to pair MI subs with a pro line array, I was extremely impressed with the result.

PS- the band was Ryan Star. Eli, the drummer, had a drum pad with a nice 808 drop which was simply staggering. There were probably over 3000 people in attendance at the show, spread out over a huge parking lot over 200 feet deep.

_MG_8236.jpg
 
Re: Jbl prx618s-xlf

Just curious, what was it that made you choose the PRX over the VRX subs? The show looks like it was fun, thanks for sharing.
 
Re: Jbl prx618s-xlf

Nice looking rig, Silas. What are the wedges on the stage? They look like PRX's too. Are they the 612M's? If so, how are they performing? What were you using for a drum wedge?

Sorry for all of the questions, just wanting to hear a real world opinion about these boxes.

Pat
 
Re: Jbl prx618s-xlf

Pat Latimer said:
Nice looking rig, Silas. What are the wedges on the stage? They look like PRX's too. Are they the 612M's? If so, how are they performing? What were you using for a drum wedge?

Sorry for all of the questions, just wanting to hear a real world opinion about these boxes.

Pat
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I had 10 PRX615m for monitors on that stage, doubled up to cover 5 performers. Drummer was happy with just the pair, in fact, his drum pad kept false triggering from the kick in the wedge.

None of the performers complained about the wedges at all, so they must have been fine. At other shows, performers have commented that the 615s are extremely loud and clear.
 
Re: Jbl prx618s-xlf

We ran 8 prx615m's and 6 prx618s-xlf's outdoors and indoors all summer doing a combination of live music and movies without issue. Our typical set-up of four of the 615's and four of the 618's set-up to cover audiences of 1-1.5 thousand have been more then sufficient and the SQ was outstanding, as long as we had them 9' high. I've got many friends in the industry running these as well and no one has reported any thermal issues what so ever.
 
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