hybrid ported with rectangular conical horn |
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jayam000
Registered User Joined: 05 September 2009 Location: India Status: Offline Points: 42 |
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Posted: 18 April 2017 at 3:42am |
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Normally the port is recatangular, square or round. here it is like horn. Any advantage? If yes, then how to calculate the same. |
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"I do not want to make my stomach a graveyard of dead animals." George Bernard Shaw
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bass*en*mass
Old Croc Joined: 03 September 2009 Location: "unknown" Status: Offline Points: 4009 |
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don keele, if i remember correctly, wrote a good article about flared ports and their influences etc.. lots of info online aswell as its still up to date tech, see new Lacoustics 218 subs for example..
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bob4
Old Croc Joined: 29 February 2004 Location: Finland/Germany Status: Offline Points: 1843 |
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except the port of this ported wbin is NOT flared at all, just increasing in cross-section. So none of that theory applies. some french guys have done research, with prototyping and measurements |
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Elliot Thompson
Old Croc Joined: 02 April 2004 Location: United States Status: Offline Points: 5175 |
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The flared port just reduce port shuffle noise. A noble idea for home audio when High SPL is not a factor. However in sound reinforcement, you would have to have a really piss poor design to have the port noise as loud as the woofer playing at high sound pressure levels.
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Elliot Thompson
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jayam000
Registered User Joined: 05 September 2009 Location: India Status: Offline Points: 42 |
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Thanks for the nice information bob4 & Elliot Thompson.
Now if we want to impliment, how to calculate? |
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"I do not want to make my stomach a graveyard of dead animals." George Bernard Shaw
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bob4
Old Croc Joined: 29 February 2004 Location: Finland/Germany Status: Offline Points: 1843 |
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If you believe so, you should carefully read the aes paper that i linked |
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mobiele eenheid
Old Croc Joined: 15 August 2004 Location: Netherlands Status: Offline Points: 1568 |
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The easiest way is to simulate the port in Hornresp, as a single segment (S1, S2, L12) with the chamber volume (Vtc in cm^3) leaving the effect of the horn out. Then approximate the ports tuning by a straight port (Ap and Lp), so that you can simulate the horn as well, now using the segments for the horn.
I haven't read the AES paper yet but I'm pretty sure that, in this particular case, the effects aren't so immense, that it justifies you learning AkAbak to fully grasp it's influence on the whole. Johan - Edit - Now that I've read the AES-paper, my advice remains unchanged ;) Edited by mobiele eenheid - 19 April 2017 at 6:47am |
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Elliot Thompson
Old Croc Joined: 02 April 2004 Location: United States Status: Offline Points: 5175 |
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I am sorry I cannot take a paper seriously with tubes longer than the actual box it is residing in. It tells me automatically that the cabinet is so small that the tubes need to be longer than the actual enclosure in order to achieve low frequencies. Ask yourself a question. How many times have you seen a Bass Reflex enclosure with ports sticking out of a box aimed for Sound Reinforcement? This paper reaps Home Audio Setup as I mentioned in my previous post why such a method would be beneficial under low SPL conditions. Under High SPL Conditions in the Sound Reinforcement World which we all do, such methods are not going offer tremendous results for the majority of the sound stems from the loudspeaker, not the port. Not everything posted in AES is aimed for Sound Reinforcement. Best Regards, Edited by Elliot Thompson - 19 April 2017 at 11:25am |
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Elliot Thompson
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jayam000
Registered User Joined: 05 September 2009 Location: India Status: Offline Points: 42 |
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Thanks to all for nice guidance.
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"I do not want to make my stomach a graveyard of dead animals." George Bernard Shaw
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bob4
Old Croc Joined: 29 February 2004 Location: Finland/Germany Status: Offline Points: 1843 |
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it's a small prototype for research….
Agreed (well, duh… )
while I'm not claiming that it's useful for PA, if you had read the blurb, you would have noticed that the nozzle shape yields notable improvements/stability in phase behavior at high input power:
I mainly wanted to point out that the nozzle port is about more than just reducing port chuffing. I don't know about you, but to me this statement in the article's conclusions is an interesting one:
I don't see why any of these principles couldn't be applied to PA systems at some point. Best Regards, Bob |
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Elliot Thompson
Old Croc Joined: 02 April 2004 Location: United States Status: Offline Points: 5175 |
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Because in the Sound Reinforcement Market we do not use a port larger than actual size of the enclosure in addition to the size of a loudspeaker in a reflex enclosure to attain greater SPL. The size of the cabinet makes a huge factor on the performance. We will use a larger enclosure to extend the frequency response. We will use multiple drivers in order to increase the coupling effect to attain more SPL in which, will offer lower distortion than forcing one speaker to do all the work. We will use woofers with the proper TS Parameters in order to attain optimum results. Phase? I would recomend measuring the impedance plots of loudspeakers in free air offering various TS Parameters. Not even a sealed back driver will be in phase once it approaches its fs. If you feel the author's idea is intriguing, build a Sound Reinforcement version of his Home Audio Bass Reflex concept, make the proper measurements and, post your findings. Best Regards, Edited by Elliot Thompson - 19 April 2017 at 3:16pm |
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Elliot Thompson
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gen0me
Young Croc Joined: 20 February 2016 Location: UK Status: Offline Points: 999 |
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Maybe the reason why port is so huge is because autor wanted to get flat response from strong speaker?
Haha is it still br or a miniscoop Just a thought: could be good idea to design telescopic brs Edited by gen0me - 19 April 2017 at 7:31pm |
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