the_garynator Posted February 18, 2013 Report Share Posted February 18, 2013 yeah basically in a TL you can either have no change in port area or have it decrease or expand (horn). and i know tl can be big. i have a 24Hz t-line that the port area doesn't change for my JL 12" right now and it takes up all the extended cab part of my truck. the sub im toying around with the idea of building a folded horn for is my 12"s baby brother. its an 8" sub same model and it's fs is around 30 Hz. i've done some reading and what not today and one person on youtube said " If the point of a horn is to be an acoustic coupling device to match he sound waves with the environment, doesn't a horn loaded enclosure become a problem in a high SPL vehicle application?" can someone help me understand the "coupling device" part of this. and thanks for your guy's input so far! that statement isn't really accurate, but I think what he means by an acoustical coupling device is the quarter wave transmission line portion of it. The purpos of a T-line is to invert the rear wave of the sub so that it provides constructive interference with the front wave (i.e. does not cancel it out). The horn side of things increases the efficiency at which the rear wave of the speaker is transferred from the enclosure to the room or vehicle cabin. I can explain how it accomplishes it, but I'm too tired right now to do it lol. Current Build: Project Flexington: 157.6db @ 37hz Parallel 6th order walk through, DC Neo Elite 18s, 4 DC 5.0ks, JY Lithium, 12 banks of XS Caps Old Builds:150db and HAIRTRICKs from 2x 12" Power Acoustik Mofos (6th order blow through) ;<p>Roadmaster Wagon Build - DC LVL 6 M3, Kicker Warhorse ; Godzilla swapped 240sx ; 6th Order Bandpass Alpine Type R 12 ; Fully loaded DC Level 5 18" 240sx Link to comment Share on other sites More sharing options...
the_garynator Posted February 18, 2013 Report Share Posted February 18, 2013 here's a decent explanation from here: http://basscouch.com/labhorn-science/: "Most people assume that a horn throws the sound, like a trumpet. Thisis not true; a horn loaded speaker does not throw sound any furtherthan a non-horn loaded speaker. In horn-loaded sound systems, the hornsare a tapered sound guide, designed to provide an acoustic impedancematch between a sound source and free air. This maximizes the efficiencywith which sound waves from the particular source are transferred tothe air. A horn does, however, minimize the unwanted volume levels behind thecabinets. This leads to less sound bleed onto the stage thannon-horn-loaded systems. This aspect is great for performers – they canhear themselves from the monitors clearer and it helps minimize theeffects of microphone feedback. Horn-loading also naturally increases the efficiency of the drivers. Ahorn-loaded speaker gains 1.5 decibels of gain per every reflection. Inthis way, the bent walls of the Labhorn naturally amplify the soundcoming out of the speakers by 6 decibels." Current Build: Project Flexington: 157.6db @ 37hz Parallel 6th order walk through, DC Neo Elite 18s, 4 DC 5.0ks, JY Lithium, 12 banks of XS Caps Old Builds:150db and HAIRTRICKs from 2x 12" Power Acoustik Mofos (6th order blow through) ;<p>Roadmaster Wagon Build - DC LVL 6 M3, Kicker Warhorse ; Godzilla swapped 240sx ; 6th Order Bandpass Alpine Type R 12 ; Fully loaded DC Level 5 18" 240sx Link to comment Share on other sites More sharing options...
HunterJohnson Posted February 18, 2013 Report Share Posted February 18, 2013 I've seen a folded horn do a 147 at 45hz off one 10" on a Rockford 1500 amp. It was in an rx-7, and the horn unloaded off the rear glass Scion tC SQ BuildiPad mini, lots of fabrication, daily drivenFord Explorer C Pillar Wall Build Just a cheap car to destroy with bass Link to comment Share on other sites More sharing options...
revoracing247 Posted February 19, 2013 Author Report Share Posted February 19, 2013 so if the purpose of a transmission line box is t basically invert the wave off the back of the driver so it's harmonious with the wave off the front. then how is it possible to create a sealed TL? in research i've seen, people have built sealed ones. I think you have a bit of truck stuck in your mud bro ~Ford Ranger, ext cabKenwood DDX4701/0ga stinger wiring for big 31/0ga ofc flextech wiring 3 kinetik 800's AQ2200 @1ohm Sundown Audio X15 in a 27Hz tuned ported box LE BUILD LOG!!! Link to comment Share on other sites More sharing options...
revoracing247 Posted February 22, 2013 Author Report Share Posted February 22, 2013 also can anyone steer me in the right direction as far as how much the horn should grow? should it be linear or exponential? also should the starting port area be smaller then the sd of the sub or should it start at the sd of the sub and grow? any help or links to stuff that will help will be greatly appreciated! I think you have a bit of truck stuck in your mud bro ~Ford Ranger, ext cabKenwood DDX4701/0ga stinger wiring for big 31/0ga ofc flextech wiring 3 kinetik 800's AQ2200 @1ohm Sundown Audio X15 in a 27Hz tuned ported box LE BUILD LOG!!! Link to comment Share on other sites More sharing options...
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