Disparity in specification: PRX618S-XLF vs VRX918SP

Silas Pradetto

Silas Pradetto

Graduate Student
Jan 11, 2011
2,130
1
0
Land of Steady Habits
www.concertsunlimited.com
OK, so I'm looking at powered subs. I know they're going to be either the JBL PRX618S-XLF or the VRX918SP. Now I have heard the PRX and I have heard the SRX718 (same box as VRX918, without the amp), and they both sound great. However, it wasn't side-by-side.

On specification alone, the PRX has 1000 watts and the VRX has 1500 watts, with the same woofer, but the PRX claims 7dB more output (133dB vs 126dB).

The boxes are close in size- the PRX box actually has a larger volume (by exterior dimensions), coming in at 9.2 cubic feet, while the VRX comes in at only 8.3 cubic feet.

To save you the time, here are links to the VRX918SP and the PRX618S-XLF

The price of the two boxes is pretty close, the PRX is about 33% less than the VRX. My main uses are small SOS gigs, rentals, drum fill, and bass fill.

I have yet another idea: buy the VRX918SP amp module and put it into an SRX718S box...I need to check on pricing, but I bet it would save all of that 33% difference in price!

Which would you buy, and why?
 
Last edited:
Re: Desparity in specification: PRX618S-XLF vs VRX918SP

Neither, just my opinion.
If you are only deciding between those two I would easily go with the VRX918SP.
I am just not a fan of the entire PRX line, there box construction seems weak and their sound leaves a bit to be desired....
Again, all my opinion.
I still say best bang for the buck, especially for a rental situation is the Yorkville LS801P.
has casters which makes it easier to move around, and, it's pretty much bullet proof for users whom may not have much experience running a PA system.
 
Re: Desparity in specification: PRX618S-XLF vs VRX918SP

Vinny D'Agostino said:
I am just not a fan of the entire PRX line, there box construction seems weak and their sound leaves a bit to be desired....
Again, all my opinion.
QUOTE]

I strongly disagree with that opinion. I wonder if you have ever heard the PRX618S-XLF? I have, and I bought four of them! As Silas said, they sound great! They are made of 18MM plywood on the sides and 24MM on top and bottom so I'm not sure where you got that weak construction idea. The Yorkville you suggest is 5/8" plywood , weighs 50 pounds more, and only goes down to 45 Hz. And the JBL has an obvious name recognition advantage for rentals. For the price(and the weight), the PRX 618S-XLF cannot be beat!

I have never compared them with the VRX, but I wonder if the larger cab contributes to the higher SPL.
Click to expand...
 
Last edited:
Re: Desparity in specification: PRX618S-XLF vs VRX918SP

Silas Pradetto said:
OK, so I'm looking at powered subs. I know they're going to be either the JBL PRX618S-XLF or the VRX918SP. Now I have heard the PRX and I have heard the SRX718 (same box as VRX918, without the amp), and they both sound great. However, it wasn't side-by-side.

On specification alone, the PRX has 1000 watts and the VRX has 1500 watts, with the same woofer, but the PRX claims 7dB more output (133dB vs 126dB).

The boxes are close in size- the PRX box actually has a larger volume (by exterior dimensions), coming in at 9.2 cubic feet, while the VRX comes in at only 8.3 cubic feet.

To save you the time, here are links to the VRX918SP and the PRX618S-XLF

The price of the two boxes is pretty close, the PRX is about 33% less than the VRX. My main uses are small SOS gigs, rentals, drum fill, and bass fill.

I have yet another idea: buy the VRX918SP amp module and put it into an SRX718S box...I need to check on pricing, but I bet it would save all of that 33% difference in price!

Which would you buy, and why?
Click to expand...

Don't despair, the disparity can be explained...

The VRX is flyable, so must be rated/measured differently (or have the measurements applied differently).

With respect to comparing two boxes with similar drivers but different enclosure volumes, I defer to Bennett's tale of two enclosures:

http://www.soundforums.net/blog/entries/14-A-Tale-of-Two-Enclosures

The devil is in the details! I'm not qualified to assess the design differences, but it might be worth doing a meaningful side-by-side comparison if you are buying a bunch of them. If you are only getting a pair, I suspect either will do fine. I had considered both those enclosures as ideal for SOS rental but also capable of kicking ass when used in large groups. 8 or 12 would be pretty scalable for a small provider. For now I continue to use separate active speakers for SOS and older horn loaded stuff for large productions.
 
Last edited:
Re: Desparity in specification: PRX618S-XLF vs VRX918SP

Chuck Simon said:
Vinny D'Agostino said:
I am just not a fan of the entire PRX line, there box construction seems weak and their sound leaves a bit to be desired....
Again, all my opinion.
QUOTE]

I strongly disagree with that opinion. I wonder if you have ever heard the PRX618S-XLF? I have, and I bought four of them! As Silas said, they sound great! They are made of 18MM plywood on the sides and 24MM on top and bottom so I'm not sure where you got that weak construction idea. The Yorkville you suggest is 5/8" plywood , weighs 50 pounds more, and only goes down to 45 Hz. And the JBL has an obvious name recognition advantage for rentals. For the price(and the weight), the PRX 618S-XLF cannot be beat!

I have never compared them with the VRX, but I wonder if the larger cab contributes to the higher SPL.
Click to expand...

And thats your opinion, and I am entitled to mine.
I will put the LS801P up against any of the PRX series subs, IMO it will win with ease.
Again, my opinion.
Click to expand...
 
Re: Desparity in specification: PRX618S-XLF vs VRX918SP

Guys we can stop arguing over other subs vs the JBLs. Vinny, I'm a Yorkville dealer but I'm also a JBL dealer, and there is only one clear winner when it comes to rentability: JBL. So, let's get back to the discussion I presented in the OP. Thanks!

PS- the LS801PB is more money than the PRX618S-XLF.

PPS- I'm leaning toward the VRX918SP.

PPPS- Vinny, we can do a shootout when I get my JBLs, OK?
 
Re: Desparity in specification: PRX618S-XLF vs VRX918SP

Also if you already own (or plan to buy) any VRX tops than the rigging on the subs might be useful at times.
 
Re: Desparity in specification: PRX618S-XLF vs VRX918SP

On the spec sheet of the VRX-SP it shows the sub was tested in full space. One nice feature of the VRX over the PRX is you can install casters on factory mounts. One issue Ive often wondered about though is the high pass out on the VRX. If engaged the crossover point is set at 80hz. (the PRX 90hz)
Probably not a issue, just wonder how well a powered 12" mid/high like a PRX612 will handle dropping that low. On the other box, its kinda nice to have stereo ins and outs for the single sub shows.
 
Re: Desparity in specification: PRX618S-XLF vs VRX918SP

Marlow Wilson said:
Don't despair, the disparity can be explained...

The VRX is flyable, so must be rated/measured differently (or have the measurements applied differently).
Click to expand...
Also look at the frequency response, with a +/-3dB response of 39-93Hz for the PRX versus 34-220Hz for the VRX getting that significantly wider response may require tradeoffs elsewhere. It could also affect which might be the best fit for some situations.
 
Re: Desparity in specification: PRX618S-XLF vs VRX918SP

Relying simply on spec sheets to compare speakers is not going to get you reliable information. The two speakers are in totally different classes. The VRX line is a touring, flyable speaker, which explains the higher costs. Peak output readings are pretty much meaningless numbers put up for bragging rights only. How does the speaker actually respond to the program material you will give it? How clean is the sound at peak power?

The PRX is a decent speaker at a decent price, but the VRX will walk all over it quality wise, even if a couple of the specs on paper look different.
 
Re: Desparity in specification: PRX618S-XLF vs VRX918SP

Brian jojade said:
The PRX is a decent speaker at a decent price, but the VRX will walk all over it quality wise, even if a couple of the specs on paper look different.
Click to expand...

Have you ever compared the two or are you just using assumptions to draw your conclusion? Are you aware that the PRX uses the same driver in a larger cab and a newer version of Crown amp and processing?
 
Re: Desparity in specification: PRX618S-XLF vs VRX918SP

Robert Kenton said:
On the spec sheet of the VRX-SP it shows the sub was tested in full space. One nice feature of the VRX over the PRX is you can install casters on factory mounts. One issue Ive often wondered about though is the high pass out on the VRX. If engaged the crossover point is set at 80hz. (the PRX 90hz)
Probably not a issue, just wonder how well a powered 12" mid/high like a PRX612 will handle dropping that low. On the other box, its kinda nice to have stereo ins and outs for the single sub shows.
Click to expand...

There is ongoing debate about whether the JBL 2268 woofer is 95dB/1 watt in whole space or half. 1000 watts is 30dB, so 95dB+30dB = 125dB, pretty close to the 126dB spec of the VRX918SP (and the amp is 1500 watts, not 1000, I'm just doing easy math here). However, there are some on this board that insist that the 2268H sensitivity of 95dB is half space...

The 7dB difference is easily explained by the difference in half/whole space (6dB) plus slight cabinet, power, and tuning differences.

I wonder, then, which one sounds better?
 
Last edited:
Re: Desparity in specification: PRX618S-XLF vs VRX918SP

Vinny D'Agostino said:
I thought the amp in the VRX918sp was only 750w continuous and 1500w peak?
Click to expand...

From a past more in-depth discussion about a year or 2 ago, it was seeming like those numbers were referring to what the built-in limiters are set to limit the internal amp to, which does make perfect sense. Thermal limiter at 750 watts, and peak limiter at 1500 watts.

Especially since seeing a pro amp rated for continuous and peak output just doesn't make a ton of sense without distortion specs. Although I am sure we have all seen weirder things that the marketing team has put on spec sheets...


Take Care,
Phil

P.S. VRX918SP would definitely be my pick Silas
 
Re: Desparity in specification: PRX618S-XLF vs VRX918SP

Brian jojade said:
Relying simply on spec sheets to compare speakers is not going to get you reliable information.
Click to expand...
I'm not sure that 'reliable' is the right word. Specs can't tell you everything including how something sounds, however specs, at least those legitimately obtained, are almost certainly more reliable than subjective opinions based on potentially varying situations.
 
Re: Desparity in specification: PRX618S-XLF vs VRX918SP

Silas Pradetto said:
There is ongoing debate about whether the JBL 2268 woofer is 95dB/1 watt in whole space or half. 1000 watts is 30dB, so 95dB+30dB = 125dB, pretty close to the 126dB spec of the VRX918SP (and the amp is 1500 watts, not 1000, I'm just doing easy math here). However, there are some on this board that insist that the 2268H sensitivity of 95dB is half space...

The 7dB difference is easily explained by the difference in half/whole space (6dB) plus slight cabinet, power, and tuning differences.

I wonder, then, which one sounds better?
Click to expand...

All this yapping got me interested enough to try and look this up.. It looks as if the VRX918SP and PRX618S-XLF both use the same driver, but unless I am missing something it is not the 2268HPL (also possibly known as the 351210-003X) as the SRX series uses. Rather, it is the 364537-001X. Although according to this, the VRX918S (NOT the VRX918SP) uses the same driver as the SRX series (351210-003X). Are they interchangeable?? That is between you and the JBL gods.
 
Last edited:
Top Bottom