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PA VS PA+ and subwoofer question

dude2010dude2010 Posts: 6
edited September 2010 in PA General Discussion
What is the difference from Driverack PA to the PA+ ?

I will be using this in my cinema system. Only.

-Is it possible to run the following:
Mono sub from deepest possible bass to 35 hz
Stereo subs from 35-100 hz
Stereo speakers from 100hz and up.

Or is there a smarter way to do this?

Comments

  • GadgetGadget Posts: 4,915
    The spec is 20-20khz +/- 0.5hz ...
    What do you have that can produce 20hz? I have the "True Sub" from Sunfire, and it is capable of 18hz (3dB down) THAT is a pretty unusual spec.. especially if you can actually do it...There are FEW systems that CAN.

    The difference in the DRPA and DRPA + is substantial.. and I would think the difference in technology would offer substantial rewards in frequency response as well... I use LABsubs live and I can tell you that the DRPA has been used on these and it is (depending on the number and power available) an "Eye opening experience" (and a liver quivering, pants flapping, near bowel loosening "experience") 6 outdoors in a cluster... 1/2 mile away caused a chest thump sensation...1 mile away it was still "felt".

    If you have the system to support the sound, the Driverack will help it come alive... Now that is not to say that "for a substantial increase to a few THOUSAND dollars and more $$$$...you couldn't "get BETTER sound", but the price may be too steep... champagne on beer budget.. pure and simple.. and with PEQ's.. the chance to ACTUALLY affect frequencies that low... nearly... priceless.

    Gadget
  • I have nothing at the moment, that's why I'm checking things out here.
    I'm playing with the thought of building a pair of Cervin Vega earthquake horns 8)

    So the difference is substatial - but is it relevant for my use?

    And is the setup mentioned possible?
  • GadgetGadget Posts: 4,915
    I have nothing at the moment, that's why I'm checking things out here.
    I'm playing with the thought of building a pair of Cervin Vega earthquake horns 8)

    If you REALLY want earthquakes you should build the LABsubs... they make those Earthquakes look like low midrange speakers:
    http://www.prosoundweb.com/article/lsp_ ... _and_more/
    So the difference is substatial - but is it relevant for my use?
    The DRPA has been discontinued...the auto eq sequence is far better, it sounds better, it's faster...win win
    And is the setup mentioned possible?
    Definitely...that is no problem
    G
  • LABsubs sounds interesting!! The JBL passive subwoofers, has a vertical rolloff below 35 hz, so still a lot missing from the film soundtrack - how are LABsub on this behalf?

    Do you have some links, images?
  • GadgetGadget Posts: 4,915
    If you REALLY want earthquakes you should build the LABsubs... they make those Earthquakes look like low midrange speakers:
    http://www.prosoundweb.com/article/lsp_ ... _and_more/

    Ummm it's all there...but they are BIG Is this for a home theater?
    G
  • Yes, it's for a god damn badass hometheater, so loud it'll clean out the ghetto :)

    But doesn't it have the same bottom rolloff problem?

    response1.gif
  • GadgetGadget Posts: 4,915
    Ummmm what sub is that? Tom Danley designed the LABsub, but he has his own company (Danley Sound)... and there is no label on the traces.

    There are a LOT of speakers that claim 30 hz and below performance... few can get below 50hz...let me put it this way... 2 labsubs in a 50X60 room... when playing Pink Floyd, Breath... things started RAINING down off the walls and ceiling. Pots and pans vibrated off their shelves and glasses were dancing on the bar :shock:

    Perhaps this is something you would like,
    http://www.billfitzmaurice.com/THT.html
    The Auto tuba is VERY impressive and the Table tuba is also with the HL10a driver...but you have to BEEF it up because the 1/2" panels will blow out well before the woofer reaches it's peak...

    Gadget
  • It's the curve, posted with the LABsub!

    The curve from Tuba here
    36Corner.gif

    Looks unrealistic clean, or so I think, especially when the want money to show the design!?

    A thing to properly have in mind, as my freind told me, every cinema has JBL systems - because the filmproducers tweek the soundtrack on JBL gear, and that makes pretty good sense to me.

    But what of these two posted hornsystems, would you prefer?
    And with what woofer?
    Or do they need two woofers?

    Would this earthquake work perhaps?
    SubZero 15"
    subzero.jpg
    http://www.earthquakedanmark.dk/produkt ... ro-15.aspx
    * 2500 Watts Max
    * 1250 Watts RMS
    * REVC = 7.80 Ohm
    * LEVC = 12.409 mH
    * Fo = 24.46 Hz
    * Sd = 89.06 msqM
    * BL = 37.8262 TM
    * Qms = 12.6551
    * Qes = 0.3021
    * Qts = 0.3021
    * SPLo = 89.7dB
    * No = 0.5877%
    * Vas = 129.65 M
    * Mechanical Xmax = 4" peak to peak
    * Electrical Xmax = 2" peak to peak
    * Cms = 114.6 uM/N
    * Mms = 369.43g
    * Mmd = 354.18g
  • GadgetGadget Posts: 4,915
    The cabinet is designed around the driver... not the other way around. To throw any old driver into an existing design (no matter how impressive the driver... isn't that an Automotive sub???) is asking for failure. There is an inherent back loading that keeps the driver from over excruding. Another consideration is the tuning of the cabinet and fs of the driver itself. *(there's a lot more to it than that though)

    As for the LABsub drivers the cab was designed around the Eminence LAB12 driver that Eminence built to Tom Danley's standards... and there are 2 in a push pull chamber... they are a BITCH to build, but are the most impressive DIY cab I have ever heard...(I build speaker cabs, and have several successful designs but NOTHING like the Lab...) 6 with about 2000 watts peak is just SICK! They were designed to b e comparable to subs costing $4000-$5000 each.. (EAW 949, Bassmaxx B zero, B1...)

    To get true 20 hz performance takes 4-6 cabs (like 27 hz and 8 will hit the low 20's...) but this is like NOTHING you have ever heard...

    As for JBL being the theater provider... I suspect it's a deal between THX and JBL... because there are a LOT more impressive subs out there than what JBL produces...On your side of the pond... D&B Audio Technik, L Acoustic, and Nexo come to mind, also EAW and Bassmaxx (the PSW has subwoofer, amplifier and speaker showdowns from time to time)

    As for Bill Fitz designs as I said the Auto Tuba is VERY impressive for it's size and does what it claims...the Table Tuba is also good as it's specs...I cannot say about the others... but plenty of folks buy the designs (and they are very cheap compared to the work necessary to "roll your own)...with all the design work and prototyping and tuning...it's really a hell of a job.

    As for the traces.. I looked up the trace and it wasn't on the site before but there is one thing you can count on... If Tom Danley publishes a spec.. you can BANK on it... Nearly ALL the other manufacturers are playing a game of "My specs are better than yours" and since there is NO standardization OR consequences for out and out lying... they continue to publish pie in the sky specifications and continue to market smoke and mirrors...

    If I was offered tickets to the SAME movie, with a JBL, or EAW system I'd pick the EAW system EVERY time, if it was Danley versus ANY OTHER SPEAKER Danley would win EVERY TIME! JBL would be the LAST for me I DO NOT care for their high end sound...it's harsh and brittle.... but that's MY opinion...

    Did you know that Tom was a Nasa engineer? His papers on ... creating earthquakes with sound, levitating liquid plasma in a sound field and Avalanche creation technology using LF sound ( type "Matterhorn sub" into a google search field you will find the truth...

    Gadget
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