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PUSH PULL18'S |
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Strange Daze 
Old Croc 
Joined: 14 July 2006 Location: United Kingdom Status: Offline Points: 2861 |
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 Topic: PUSH PULL18'SPosted: 17 January 2008 at 3:02pm |
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was just curious, as i dont know much about the theory of PushPull subs, whether they 'couple' in the same way as multiple reflex cabs... the reason i ask, is that ive been offered a few at a goo price, but im not gonna have 2 x duel 18s a side if im gonna have phase or coupling issues.....
And ideas??...
Cheers,
Chris.
ps- i did originally post this in Newbie discussion, but it wasnt replied to.
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ceharden
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Joined: 05 June 2005 Location: Southampton Status: Offline Points: 11851 |
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Posted: 17 January 2008 at 3:19pm |
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When you say push-pull, you mean a twin 18" with one driver reversed and facing into the cab?
They will perform just the same as one with the drivers facing the same way but with the added advantage of cancelling distortion due to non-symetrical motion of the cone. |
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Strange Daze
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Posted: 17 January 2008 at 4:05pm |
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spot on... thats all i needed to know....
Cheers bro :)
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Robbo
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Joined: 05 December 2005 Location: Shropshire Status: Offline Points: 4297 |
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Posted: 17 January 2008 at 4:09pm |
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We have four Logic System 2x18 push/pull cabinets loaded with 1000 watt PHL drivers and we have been driving them with an Electrovoice P2000 bridged into each cabinet---they are quite compact and light boxes for a 2x18 and everyone has been gobsmacked on hearing them---just using one a side in a smaller venue can re-arrange your internal organs if you stand in front of them and if you think the Logic 2x15 push/pull is good then you want to hear these 2x18 versions.
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speaker monkey
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Joined: 15 January 2008 Status: Offline Points: 279 |
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Posted: 17 January 2008 at 5:46pm |
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Ive never really looked into or done anything with push pull. I was just wanderin, surely the drivers would be out of time (not out of phase obv) because of the different positioning of the relative cones.
I can see how someone would say that the wavelengths are so big with such frequencies that it wont make a difference, but everything makes a little difference. Or does the cab compansate for this? Or do you delay one of the drivers..?
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HansA
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Joined: 07 March 2007 Location: Norway Status: Offline Points: 595 |
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Posted: 17 January 2008 at 6:21pm |
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I't wont matter. They are to close together in a to low frequenzy band to be noticable.
The difference would be greater between two cabinets than within a push-pull setup. Edited by HansA - 17 January 2008 at 6:21pm |
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�*�o�O�o�*�*: HansA, The FUBAR sound technician :*�*�o�O�o�*�
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tb_mike
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Joined: 01 October 2004 Location: New Zealand Status: Offline Points: 2744 |
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Posted: 18 January 2008 at 1:53am |
Youve got to visualise the wavelengths involved,calculate some,say 40hz and 400hz. If sources are within 1/4 of a wavelength apart, they might as well be called ' in phase' since there is no cancellations occuring.Perhaps higher up it will need to be filtered sharply to avoid any comb filtering etc. |
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snowflake
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Posted: 18 January 2008 at 12:41pm |
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if you are going to reverse a driver check that there is not any significant vent noise. some very good drivers have vent noise that is usually inaudible because it is contained inside the speaker chamber.
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_djk_
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Joined: 23 November 2004 Location: United States Status: Offline Points: 5992 |
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Posted: 18 January 2008 at 1:45pm |
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djk
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ychole audio
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Joined: 18 January 2007 Location: United States Status: Offline Points: 625 |
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Posted: 18 January 2008 at 11:21pm |
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Does anyone got plans for a push-pull cab,primarily for 18' drivers?Thanks..
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I am ZERIEL'S dad!!!
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_djk_
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Posted: 19 January 2008 at 11:50am |
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Boxes have to be designed for specific drivers, some 21" drivers actually work in smaller boxes than the typical 18".
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djk
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TOTALLYORANGE events
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Joined: 07 May 2025 Location: Poole Status: Offline Points: 4 |
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Posted: 19 February 2026 at 3:18pm |
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Any chance you could send me pics of the internal of the logic cabs as I am trying to recreate them myself and I am having trouble finding a plan hopefully you can help 🤞🏻
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speaker monkey wrote: