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Sound Reinforcement - Forums for Live Sound Professionals - Your Displayed Name Must Be Your Real Full Name To Post In The Live Sound Forums => LAB Lounge => Topic started by: Will Curran on July 28, 2011, 10:36:40 PM
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Hey guys,
I'm in the process of putting some of our cash to start building a powered JBL VRX system. I'm hoping to buy (4) VRX932LAPs in the next week or so, and until we get the final cash to finish the system- renting the 918 subs and more tops from a production company.
However the production company only has the passive 932LAs and passive 918S. I concerned about hanging the powered units with the passive units on the same array. Will this be a major problem or something a Driverack 260 could fix (if so what are your thoughts on fixing this)?
I don't want to turn this into a powered vs passive battle. I am buying powered for the easy of setup.
Let me know your thoughts.
Thank you!
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In my opinion it's not any harder to patch a passive system in many ways it's easier. If you will be crossrenting in the future to increase the size of your rig. Or possibly renting to help another company it would be best if you had the same gear.
Hey guys,
I'm in the process of putting some of our cash to start building a powered JBL VRX system. I'm hoping to buy (4) VRX932LAPs in the next week or so, and until we get the final cash to finish the system- renting the 918 subs and more tops from a production company.
However the production company only has the passive 932LAs and passive 918S. I concerned about hanging the powered units with the passive units on the same array. Will this be a major problem or something a Driverack 260 could fix (if so what are your thoughts on fixing this)?
I don't want to turn this into a powered vs passive battle. I am buying powered for the easy of setup.
Let me know your thoughts.
Thank you!
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In my opinion it's not any harder to patch a passive system in many ways it's easier. If you will be crossrenting in the future to increase the size of your rig. Or possibly renting to help another company it would be best if you had the same gear.
Absolutely know where you are coming from. So it would be convenient to have the same gear but not necessary?
Do you guys have any suggestions for amps to power the passive 932LA that would allow me to stay within original budget for the powered 932LAPs?
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Absolutely know where you are coming from. So it would be convenient to have the same gear but not necessary?
Do you guys have any suggestions for amps to power the passive 932LA that would allow me to stay within original budget for the powered 932LAPs?
Well, what is the company you are cross-renting from using?
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Well, what is the company you are cross-renting from using?
Lab.Gruppen FP-1000Qs however I have little knowledge on these amps and can't even find the pricing on them (and by the looks of them I doubt they are cheap). I feel like it may be cheaper for me to purchase a Driverack 260 and tweet the passive to match the powered, and I will eventually build up my system to the point where I will not need to cross rent.
From what it seems, something like the XTI6000 would be my best bet, and would powered a cluster of 2 meaning I would only need 2 amps.
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Will,
Here's the deal. Passive or powered it's a speaker and an amplifier. Match your amps to your speakers, follow JBLs guidelines, and you should be all set. Personally I prefer passive boxes. I can mix and match at will, pull a failed amp (I've never had one), change cabinets, etc..
The 260 is a good DSP, but remember there are two (2) inputs and six (6) outputs, which limits it's use should you decide to increase the size of your array. However, with a pair of 932LAs on both sides you should do OK with the combination running them with a 260 as long as they are daisy chained and properly powered. Properly powered to me is an amp that can output twice the long term rating of the cabinet. Not that you'll use that amount of power, but you'll have enough headroom to eliminate the possability of clipping the amps and destroying your drivers. Others may not agree with my simplistic math, but few can claim fewer than a pair of blown drivers and zero failed amps with over 40 years of driving speakers hard.
The Labs by the way are top of the line amplifiers. You'll do just fine though with QSC or Crown products in their place. Stay away from the cheaper wannabe's, and invest your money wisely.
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Properly powered to me is an amp that can output twice the long term rating of the cabinet. Not that you'll use that amount of power, but you'll have enough headroom to eliminate the possability of clipping the amps and destroying your drivers. Others may not agree with my simplistic math, but few can claim fewer than a pair of blown drivers and zero failed amps with over 40 years of driving speakers hard.
::)
Really?? Hasn't this been debunked enough?
It's more than possible to clip a LabGruppen FP14000 which could destroy a pair of VRX boxes faster than pretty much any other amp on the planet, and to not clip a Peavey CS400 which would power at less than maximum capacity a pair of VRX boxes indefinitely with no danger of damage ever. For that matter, a pair of VRX boxes would likely handle a fairly severely clipped CS400 for an extended period of time. Headroom doesn't eliminate the possibility of clipping the amps - the user's brain should - unless they have too much empty "headroom" in their noggins. It's not the shape of the waveform, it's the area under the curve that matters.
I agree that it's good practice to have an amp with some headroom, but in my experience that has almost nothing to do with the user choosing to clip it or not.
Oh, and I'm on pace to beat your record - 15+ years with zero driver failures.
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As has been the case in the past I stand by my 2x statement and agree this may not always be the most optimal solution as noted below, but it is a recommendation based on solid fact which I have followed since day one. In any case almost every manufacturer of note will also recommend 2x the rating. EAW puts this into easily understood text;
"Preventing Loudspeaker Damage - Preventing damage to or failure of a loudspeaker is not a function of amplifier size nor the loudspeaker's power rating. Preventing damage is a function of operating an audio system so that a loudspeaker is not stressed beyond its limits. If an audio system is operated improperly, damage to or failure of a loudspeaker can occur even with an amplifier sized well below the loudspeaker's power rating. Contrarily, if an audio system is operated properly, damage to or failure of a loudspeaker can be avoided even with an amplifier sized well in excess of the loudspeaker's continuous (or RMS, average, etc.) power rating.
Selecting an Appropriate Amplifier Size - The amplifier for your loudspeaker should be sized according to both the sound levels required and the type of audio signals that will be reproduced. If you are unsure of how to determine these things, consult a qualified professional or contact EAW's Application Support Group. As a rule of thumb, where the full capability of the loudspeaker is needed to achieve appropriate acoustic output levels, EAW recommends an amplifier that is twice the loudspeaker's power handling specification. This allows the amplifier to reproduce peaks 6 dB above the specified power handling. However, this recommendation does NOT guarantee trouble-free operation, and assumes that operation of the loudspeaker can be properly controlled. It is the responsibility of the audio system operator to ensure that all equipment in the system is operated within its capabilities. That is the only way to ensure that loudspeakers do not get stressed beyond their limits to the point of damage or failure."
http://www.jblpro.com/catalog/support/getfile.aspx?docid=246&doctype=3 (http://www.jblpro.com/catalog/support/getfile.aspx?docid=246&doctype=3)
http://www.jblpro.com/catalog/support/getfile.aspx?docid=290&doctype=3 (http://www.jblpro.com/catalog/support/getfile.aspx?docid=290&doctype=3)
http://www.eaw.com/support/faq/#AmpSize (http://www.eaw.com/support/faq/#AmpSize)
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As has been the case in the past I stand by my 2x statement and agree this may not always be the most optimal solution as noted below, but it is a recommendation based on solid fact which I have followed since day one. In any case almost every manufacturer of note will also recommend 2x the rating. EAW puts this into easily understood text;
"Preventing Loudspeaker Damage - Preventing damage to or failure of a loudspeaker is not a function of amplifier size nor the loudspeaker's power rating. Preventing damage is a function of operating an audio system so that a loudspeaker is not stressed beyond its limits. If an audio system is operated improperly, damage to or failure of a loudspeaker can occur even with an amplifier sized well below the loudspeaker's power rating. Contrarily, if an audio system is operated properly, damage to or failure of a loudspeaker can be avoided even with an amplifier sized well in excess of the loudspeaker's continuous (or RMS, average, etc.) power rating.
Selecting an Appropriate Amplifier Size - The amplifier for your loudspeaker should be sized according to both the sound levels required and the type of audio signals that will be reproduced. If you are unsure of how to determine these things, consult a qualified professional or contact EAW's Application Support Group. As a rule of thumb, where the full capability of the loudspeaker is needed to achieve appropriate acoustic output levels, EAW recommends an amplifier that is twice the loudspeaker's power handling specification. This allows the amplifier to reproduce peaks 6 dB above the specified power handling. However, this recommendation does NOT guarantee trouble-free operation, and assumes that operation of the loudspeaker can be properly controlled. It is the responsibility of the audio system operator to ensure that all equipment in the system is operated within its capabilities. That is the only way to ensure that loudspeakers do not get stressed beyond their limits to the point of damage or failure."
http://www.jblpro.com/catalog/support/getfile.aspx?docid=246&doctype=3 (http://www.jblpro.com/catalog/support/getfile.aspx?docid=246&doctype=3)
http://www.jblpro.com/catalog/support/getfile.aspx?docid=290&doctype=3 (http://www.jblpro.com/catalog/support/getfile.aspx?docid=290&doctype=3)
http://www.eaw.com/support/faq/#AmpSize (http://www.eaw.com/support/faq/#AmpSize)
Your quotations say nothing about a larger amp preventing clipping. They recommend a larger amp for some transient headroom, but they emphasize "proper operation" - which is clip avoidance by using your brain, not a larger amplifier.
I don't disagree with the 2x rating for performance, but I strongly disagree with the statement that a larger amp will make any difference in whether it's operated into clipping or not. An analogy is a poor driver in a Porsche Boxster who crashed his car by being an idiot, and bought a Bugatti Veyron because he believes the faster car will give him enough "headroom" so that he won't crash again when he drives outside the limits of the road system.
It's not what amp you have, it's the driver in the seat.
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Tom,
We're actually saying the same thing although I've probably made it hard to understand. Yes, I agree with you and to clarify my statement, 2x is usually the right way to go, but regardless of amp size a fool and his speakers are soon parted.
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Alright, thanks for that guys. Does anyone else have more feedback on mixing the powered VRX932LAP and the passive VRX932LA-1 while I build up my inventory?
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Alright, thanks for that guys. Does anyone else have more feedback on mixing the powered VRX932LAP and the passive VRX932LA-1 while I build up my inventory?
It doesn't make any difference in a properly configured rig. You only need to match the output levels between the "passive" rig and the self-powered rig. If you can't do this by ear you should buy Cerwin Vega.
You will not find "budget" amps that will provide the same performance as the Lab Gruppens; many would argue that I-Techs are inferior to the LG.
Have fun, good luck.
Tim Mc
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Alright, thanks for that guys. Does anyone else have more feedback on mixing the powered VRX932LAP and the passive VRX932LA-1 while I build up my inventory?
It's totally doable and a seamless tie-together. I have 2+2 powered (per side), a buddy has 2+2 passive (per side) with crown amps. We put them together all the time with no issues at all.
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I tread carefully here..
I have yet to hear the VRX sound anything short of harsh..and for the money spent, I personally would look at other systems.
According to other posts I have read here on PSW, if one was in the market for a constant curvature array, and willing to go passive, I think perhaps the EAW JFL210 is worth a look-especially processed with the UX8800.
As for the cross renting issue, in many applications, there is a limit to how many of these boxes one can effectively deploy anyway-it's not like if you have 4-6, you are going to need 6 more.
Just my thoughts.
NOT a dealer for any of the above mentioned products ;)
p.s. on the amp power thing--we run 8 Eaw La400's on a QSC PL9.0 , and , sometimes 4/4 on PL6/PL6.. Eaw says 500watts/cab long term, they have avail. to them up to 1125 ish continuous, each !!
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Tom,
We're actually saying the same thing although I've probably made it hard to understand. Yes, I agree with you and to clarify my statement, 2x is usually the right way to go, but regardless of amp size a fool and his speakers are soon parted.
That's a relief - I was pretty shocked to hear the old "a bigger amp prevents clipping" argument from you - glad it was just miscommunication.
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I tread carefully here..
I have yet to hear the VRX sound anything short of harsh..and for the money spent, I personally would look at other systems.
According to other posts I have read here on PSW, if one was in the market for a constant curvature array, and willing to go passive, I think perhaps the EAW JFL210 is worth a look-especially processed with the UX8800.
As for the cross renting issue, in many applications, there is a limit to how many of these boxes one can effectively deploy anyway-it's not like if you have 4-6, you are going to need 6 more.
Just my thoughts.
NOT a dealer for any of the above mentioned products ;)
Hello! TJ - chief JFL fanboy here!
I have a lot of time on my church's VRX system, and I own the EAW JFLs personally. The JFL210 is a more balanced design than the VRX - one horn and two 10" compared to the VRX's 3 horns and one 12". There's 40% more cone area in the JFL, which gives it a little more capability in the low midrange. With the UX8800 the system is pretty low distortion and gets equally loud as the VRX, and IMO, sounds better. Cabinet cost is about the same, though adding the UX8800 increases the price quite a bit, though worth every penny.
The JFL118 subs equal the VRX918s.
All this great stuff aside - the business decisions (if you're trying to run a business) need to rule, and cross renting may be a factor for you. I agree with Dean that you're not likely to rent 20 more of these to use in the same system, but it's conceivable that one could use as many as 12 in a realistic good deployment - 4 hangs of 3 to cover a thrust stage in a room with the stage on the long wall.
A lot of people will comment on VRX blight - not that the VRX system is bad - it isn't, but that lots of people want to own a "line array", and think that's what the VRX system is. These folks then advertize their "line array", and deploy it in completely inappropriate ways with inappropriate expectations, and the corresponding poor results.
My world is quasi-corporate stuff. I wanted a low profile, lightweight, high output, flyable system that sounds really good and is appropriate for medium size hotel ballrooms. The 110 X 30 pattern I get with the JFLs is usually perfect for me, and the output, evenness, and throw meet my expectations in a 60 X 100 ballroom, throwing 80' or so. For other applications, a SOS trap system may be better.
Not to derail too far, but I did a review of the JFLs a while back.
http://srforums.prosoundweb.com/index.php/t/51170/0/