Posted April 14, 200520 yr Kent asked for this a while ago... I dug up some links.Enjoy.http://audioforum.termpro.com/cgi-bin/ubb/...ic;f=8;t=021625http://forum.soundillusions.net/showthread.php?t=45647http://hyperphysics.phy-astr.gsu.edu/hbase/pfric.htmlGood reading, good points, easy read.-Nick
April 14, 200520 yr thanks man!!!so it's about air slowing down at the edges and the actual tuning freq that it produces...in a nutshell...wheeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee
April 15, 200520 yr Admin I wanted to get a discusison on standing waves, hence the reason I at least 45 out all my internal corners
April 15, 200520 yr Author standing wave or cancellation..?two similar animals with very different resolutions. in theory at least -Nick
April 15, 200520 yr Admin standing wave or cancellation..?two similar animals with very different resolutions. in theory at least -Nickstanding waves, usually caused by air flow having to bend around corners and those corners not being smooth, so some air flow gets trapped in a counter rotational motion in the corners, makeing the final execution of the enclosure not as efficentwell atleast thats how I understand it
April 15, 200520 yr so what if we applied some sort of 'smoother' surface to the inside of the port? like a layer of fiberglass resin wetsanded to shinyness?would this make the turbluance go down noticeably?
April 15, 200520 yr Author standing waves, usually caused by air flow having to bend around corners and those corners not being smooth, so some air flow gets trapped in a counter rotational motion in the corners, makeing the final execution of the enclosure not as efficentwell atleast thats how I understand it <{POST_SNAPBACK}>What You're describing isnt standing wave, but I cant recall wht the ef it is... Vortex...? chit. Anyhow, You are right on with the problem though. More bends OR surface area are bad. But when you're talking about a vortex (?), this is where the famous 45* corner boards come into play. Standing wave is when the internal wall layout causes waves to cancel eachother out in direct fashion. -or- the perfectly cubic box (12x12x12)... a single wave will reflect and destroy itself. iirc.You absolutly struck the nail on the head though.... making the final execution of the enclosure not as efficent The key is to try to get the box as efficient as possible. Though... I'm still newbish.
April 15, 200520 yr Author fiberglass, turtle wax, duct tape, 45* boards, cust & glassed cardboard tubes... these have all made differences for me in the past. Some more then others, but as always - it varied by box & car.
April 15, 200520 yr Isn't a perfectly round enclosure ideal for eliminating standing waves and turbulence like vortexes.
April 15, 200520 yr Admin Nick your right, the vortex effect is the swirlling air caught in the corners
April 15, 200520 yr Author Isn't a perfectly round enclosure ideal for eliminating standing waves and turbulence like vortexes.<{POST_SNAPBACK}>Yes it is... in theory. I've never seen anyone try it realistically. I'd love to If I could think of a decent way to implement it... But that would bring on all new issues of linearity, tuning, backwave control & cone control...
April 15, 200520 yr Admin I thought that is what RF did with their Xterra install a few years ago, with the huge bongo like suspended enclosures
April 17, 200520 yr i saw an add for a perfectly round enclosure in a car audio & performance mag...some company i can't remember it, i'll try and dig it up....
April 20, 200520 yr [More bends OR surface area are bad. More surface area implies more port area ...
April 21, 200520 yr Author [More bends OR surface area are bad. More surface area implies more port area ...<{POST_SNAPBACK}>implies in the conventional term, but thats not accounting port wall surface.
July 25, 200520 yr Round edges or 45 deg helps eliminate standing waves and it is good for SQ but SPL is other thing. If SPL box is made correct then you should make standing waves inside box and all 45 deg or smooth corners destroy them. All boxes from 1st, 2nd...places I saw arround the European 3x competitions were made in this maner. When you create standing wave in box at right freq. than you gain your SPL quite a bit.It also help if you make your box and port inside as smooth as you can!!!! difference can be up to 0.5 dB. Be wery careful when you do bracing!!! braces MUST have smooth edges!!! But at first try without it!!!!
July 25, 200520 yr Author generally, You wont have standing waves with subbass frequencies... the wavelength is just too long.
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.