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[Will Curran]

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!

[Thomas Lamb]

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!

[Will Curran]

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?

[Chris Carpenter]

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?

[Will Curran]

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.

[Bob Leonard]

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.

[TJ (Tom) Cornish]

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.

[Bob Leonard]

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=290&doctype=3

http://www.eaw.com/support/faq/#AmpSize

[TJ (Tom) Cornish]

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=290&doctype=3

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.

[Bob Leonard]

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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