DBX DriveRack PA2

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HugoMack
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Re: DBX DriveRack PA2

#61 Post by HugoMack »

Totally Grant!! You've nailed it for me. Many thanks. The Crowns are 2-8 Ohms which seems like the best option for the subs. I'll re-read your explanation and go back through the specs I've been considering. THanks again.

And as Bill explains, the Lab 12 has by far the largest driver displacement so runs louder than the alternatives.

One qualification - I assume your in 810W @ 4 Ohms , the watts are RMS?
Hugh McManners
2x Jack 12 Lite 3012HOs, Matrix GT800. DBX PA2 Next 20 inch T39's with 3012's (LF). Sound reinforcement, then projection. FRFR. Love huge PAs, but at that stage in life when technology needs to make things easier (as in lighter!)

HugoMack
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Re: DBX DriveRack PA2

#62 Post by HugoMack »

[quoteSo, tins tacks, if you were to run 2 x T39's channel, with lab 12's, to 50V (damn that would be loud), you might want an amp that is capable of say 57V/channel @ 4 ohms. That's about 810W/4ohms.
Ideally your amp would be 2 ohm load capable as well, for a little added safety in trms of impedance.[/quote]

This does pretty well conform to the traditional 2x AES of your speakers approach. Getting voltage output readings from this amp manufacturer is proving problematic. So the Crown XLS 2500 looks like a good contender to drive the subs.

I'm driving the tops at the moment with a Matrix GT800, which is under-powered - although sounds very nice - and is certainly loud. http://uk.matrixamplification.com/rack- ... 00-fx.html

I'm looking at this to replace it for my Jack 12 Lites. (I like Matrix amps, which seem to me to be better than the Crowns, but nothing like as expensive as the next level up.
http://pa.matrixamplification.com/xt-2u ... t2000.html

Seems to me also that paying more for amps that have limiting and other DSP-type functions is self-defeating; do it all once before any signal goes into a power amp...? So I'm looking for an amp this isn't making me pay for functions I'm using the DBX PA2 to perform?

STOP PRESS!! I'm being offered a really great deal on this:
http://pa.matrixamplification.com/xt-4- ... t4004.html These Matrix are good.... I'd be very grateful for your opinions.

Carrying around a PA and then playing through it. this offers all sorts of advantages - running foldback with a two-way system from just the one rack... Everything's on stage anyway...
Hugh McManners
2x Jack 12 Lite 3012HOs, Matrix GT800. DBX PA2 Next 20 inch T39's with 3012's (LF). Sound reinforcement, then projection. FRFR. Love huge PAs, but at that stage in life when technology needs to make things easier (as in lighter!)

HugoMack
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Re: DBX DriveRack PA2

#63 Post by HugoMack »

Is "Slew Rate" the same as what you'd see on your DC voltmeter with a power amp on max - it being volts per second...? (Im still trying to relate amp specs to my needs - with much greater understanding :fingers: I think
Hugh McManners
2x Jack 12 Lite 3012HOs, Matrix GT800. DBX PA2 Next 20 inch T39's with 3012's (LF). Sound reinforcement, then projection. FRFR. Love huge PAs, but at that stage in life when technology needs to make things easier (as in lighter!)

Bruce Weldy
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Re: DBX DriveRack PA2

#64 Post by Bruce Weldy »

Since I'm lazy and don't want to go back and read pages of posts......which cabs, which drivers, how many?

6 - T39 3012LF
4 - OT12 2512
1 - T24
1 - SLA Pro
2 - XF210


"A system with a few knobs set up by someone who knows what they are doing is always better than one with a lot of knobs set up by someone who doesn't."

HugoMack
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Re: DBX DriveRack PA2

#65 Post by HugoMack »

Jack Lite 12 3012HO x2

T39 24" Lab 12 x2
Hugh McManners
2x Jack 12 Lite 3012HOs, Matrix GT800. DBX PA2 Next 20 inch T39's with 3012's (LF). Sound reinforcement, then projection. FRFR. Love huge PAs, but at that stage in life when technology needs to make things easier (as in lighter!)

Bruce Weldy
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Re: DBX DriveRack PA2

#66 Post by Bruce Weldy »

HugoMack wrote:Jack Lite 12 3012HO x2

T39 24" Lab 12 x2
If you are trying to run all four off one amp, then get one that will do 1000 watts per channel at 4 ohms. That's plenty of headroom and it won't run too hot.

QSC GX7 would be a perfect fit. Do DSP, lightweight and fairly cheap.


If you want separate amps for mains and subs, then you'll need a amp for the subs that will do 500 watts per channel at 8 ohms. Again the QSC GX7 is a good fit.

For tops, you shouldn't need more than 300 watts per channel at 8 ohms....you'll probably never use that much.

As far as reading manufacturers' info - always go with the absolute lowest figure that they give for power.

6 - T39 3012LF
4 - OT12 2512
1 - T24
1 - SLA Pro
2 - XF210


"A system with a few knobs set up by someone who knows what they are doing is always better than one with a lot of knobs set up by someone who doesn't."

Grant Bunter
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Re: DBX DriveRack PA2

#67 Post by Grant Bunter »

One qualification - I assume your in 810W @ 4 Ohms , the watts are RMS?
Yes.
Others might say "average" power". There is no consistency on a brand to brand basis about all the terms, as you've probably discovered.
You certainly don't want that as peak power though.

Bruce's suggestion of 1000W/4ohms is pretty solid. That's around 63V.

Just to clarify what I was saying about being able to limit.
Point in case was old mate from this forum who was trying to use a JBL MPX1200 amp, which does 69V/4ohms. Turns out that amp needed the limiter on DSP set at max reduction (-24dB???) to get 50V, but in doing so, meant he was into the limiter pretty much constantly with the sliders up. This is what you don't want.
I would ballpark limiting 63V to 50V would be roughly 12-14dB reduction.

I know you like them, but that 4 channel amp seems a bit pricey. Otherwise looks great.
I understand, 2RU vs 4 for 2 amps, but still...
Built:
DR 250: x 2 melded array, 2x CD horn, March 2012 plans.
T39's: 4 x 20" KL3010LF , 2 x 28" 3012LF.
WH8: x 6 with melded array wired series/parallel.
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HugoMack
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Re: DBX DriveRack PA2

#68 Post by HugoMack »

This is so helpful Grant and Bruce. Many thanks.

I've been offered 30% off the Matrix pa amps, so they seem less pricey.

I'll take a good look at the QSCs. Thanks for that.

I know there are discussions covering much of this - and that when asking my questions I might have missed previous answers that could have helped. But on the other hand, technology moves on and this discussion developed from my specific PA2 (new model) questions.

There's such a lot of generally useful info you've all given me, that I wonder if some kind of BFM Wiki could be a good move? Fractal Audio (Axe FX) have a really great one, which runs within their site. I cite this because I don't think Fractal would have had anything like the same success without their Forum and Wiki. BFM cabs are a long-running success, but I'm sure this great Forum can attract more new converts like me; and that the level of info here is at a threshold where a wiki would help.

http://wiki.fractalaudio.com/axefx2/ind ... _Wiki_Home

Context is so important with these complex issues. A Wiki allows everyone to develop information under headings as opposed to a conversation with a unique context. These entries can then develop in parallel with the technology. And this then provides easy-to-find web links to existing answers.
Hugh McManners
2x Jack 12 Lite 3012HOs, Matrix GT800. DBX PA2 Next 20 inch T39's with 3012's (LF). Sound reinforcement, then projection. FRFR. Love huge PAs, but at that stage in life when technology needs to make things easier (as in lighter!)

tuna
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Re: DBX DriveRack PA2

#69 Post by tuna »

I just picked up a PA2 and integrated it into my system. I was hoping it was going to be a replacement for the DCX/DEQ combo. It is not. I still had to use my DCX for output. The PA2 has 3 pairs of outputs: 2 highs, 2 mids, and 2 lows. While the Lows allow for a mono hookup, the highs and mids DO NOT. It requires both outs to be connected for any of the auto-eq and RTA functionality to work. The outputs are not nearly configurable enough for the individual channels to come anywhere close to do what the DCX can do.

As for the EQ, I liked the functionality. For whatever reason it sounds better to me than the DEQ/DCX combo. The ipad control is quite nice, and the RTA functionality works great. I hung the RTA mic in the middle of my room and it constantly responds to music and sound as it is playing. To me, it sounds great.

Pros: Auto EQ and Room Correction works and sounds great. Ipad control via wifi.
Cons: Analog input only. Ipad control requires a network connection and yet no built in wifi.

Looks to me that rather than putting out an actually usable product, they put out a product that has some nice new features unavailable anywhere in the market to develop hype. But then made them stand alone in a product that is useless without interfacing with other products. In other words it is crippled. Lack of digital input support, lack of ability to configure the outputs are the two biggest things I have run into. I fully expect to see a PA2+ come out that will actually be useful as there is no other reason to exclude some of the stuff they have excluded in this product.

byacey
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Re: DBX DriveRack PA2

#70 Post by byacey »

tuna wrote: As for the EQ, I liked the functionality. For whatever reason it sounds better to me than the DEQ/DCX combo. To me, it sounds great.
It should sound better. DBX was in the Pro audio world doing their own product development and design decades before Behringer arrived on the scene attempting to break into the pro-audio market by half-assed cloning and riding on the coat tails of other manufacturer's product designs.
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Bruce Weldy
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Re: DBX DriveRack PA2

#71 Post by Bruce Weldy »

tuna wrote: The PA2 has 3 pairs of outputs: 2 highs, 2 mids, and 2 lows. While the Lows allow for a mono hookup, the highs and mids DO NOT. It requires both outs to be connected for any of the auto-eq and RTA functionality to work.
Explain what you mean here.....I have all three DR models prior to the PA2 and run them all in mono and the RTA and autoEQ work just fine with only one side connected.

6 - T39 3012LF
4 - OT12 2512
1 - T24
1 - SLA Pro
2 - XF210


"A system with a few knobs set up by someone who knows what they are doing is always better than one with a lot of knobs set up by someone who doesn't."

tuna
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Joined: Wed Aug 10, 2011 7:16 pm
Location: San Diego, CA

Re: DBX DriveRack PA2

#72 Post by tuna »

Well, on the mid and high output sections the system would go in a particular order lets say left-mid, right-mid, left-high, right-high. As soon as it would run into an unconnected output everything would fall over. As in it would stop and not allow you to move forward. Also, the right output was automatically assigned to the right input and vice versa. It was not possible to reconifigure this for left or vice versa. Sum signal was allowed but again, as soon as a physical connection was made everything would stop.

Bruce Weldy
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Joined: Fri Nov 27, 2009 11:37 am
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Re: DBX DriveRack PA2

#73 Post by Bruce Weldy »

tuna wrote:Well, on the mid and high output sections the system would go in a particular order lets say left-mid, right-mid, left-high, right-high. As soon as it would run into an unconnected output everything would fall over. As in it would stop and not allow you to move forward. Also, the right output was automatically assigned to the right input and vice versa. It was not possible to reconifigure this for left or vice versa. Sum signal was allowed but again, as soon as a physical connection was made everything would stop.
Sounds like you are trying to use the set up wizard......if so, don't. Just do a custom setup and put in your own parameters.

And you are right, the inputs and outputs are not assignable. Don't see why that's really necessary for a two-way, or even three-way system. What are you trying to do with it other than run the mains?

6 - T39 3012LF
4 - OT12 2512
1 - T24
1 - SLA Pro
2 - XF210


"A system with a few knobs set up by someone who knows what they are doing is always better than one with a lot of knobs set up by someone who doesn't."

HugoMack
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Re: DBX DriveRack PA2

#74 Post by HugoMack »

Looks to me that rather than putting out an actually usable product, they put out a product that has some nice new features unavailable anywhere in the market to develop hype. But then made them stand alone in a product that is useless without interfacing with other products. In other words it is crippled. Lack of digital input support, lack of ability to configure the outputs are the two biggest things I have run into. I fully expect to see a PA2+ come out that will actually be useful as there is no other reason to exclude some of the stuff they have excluded in this product
.

I preferred setting up my own DHCP wireless router, which is velcro'd inside my SKB. It's a potentially dangerous over-complication to have a device like this also running the network. Better to have a dedicated router that you can replace if necessary at little cost, with good security. BUt is that what you meant by its 'lack of digital input support"?

You don't sound you like your PA2 very much, but I have to say that I don't understand your comments about configuring outputs. The options seem to cover most likely uses. However like you I've not had mine for very long, so I've only tried the options I actually use. Which seem fine. There'd be no point using the same settings to run foldback for example. ...
Hugh McManners
2x Jack 12 Lite 3012HOs, Matrix GT800. DBX PA2 Next 20 inch T39's with 3012's (LF). Sound reinforcement, then projection. FRFR. Love huge PAs, but at that stage in life when technology needs to make things easier (as in lighter!)

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BrentEvans
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Re: DBX DriveRack PA2

#75 Post by BrentEvans »

Bruce Weldy wrote: And you are right, the inputs and outputs are not assignable. Don't see why that's really necessary for a two-way, or even three-way system. What are you trying to do with it other than run the mains?
It's nice if you want to do things like sidefills, delay stacks, etc, or if you're doing something more complex than a stereo plus subs configuration.

Unfortunately the Driverack units (at least the lower end models) have always been a basic DSP for stereo PAs, nothing more. If you need something more complex, you're going to be spending more money. With the advent of digital mixers with fifty eleven outputs, this need is minimized somewhat, but it's still nice to just feed a stereo out to a processor and have all the settings locked away.
99% of the time, things that aren't already being done aren't being done because they don't work. The other 1% is split evenly between fools and geniuses.

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