I have a question....why did this work?
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Gold Member Username: InsearchofbassPost Number: 4916 Registered: Jun-04 | I had some low grade 6.5 midbasses and stuck a single midbass in about a 6 ft. 6 inch pvc tube........transmission line style basically and this midbass listed 60 hz as the lowest playable frequency but it played all the way down to 20 hz at about 90 db on my handheld digital spl meter in my friends house on about 70 to 90 rms power...why is it able to do that when its only supposed to be able to play down to 60 hz? |
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Silver Member Username: J_baby15Kentucky Post Number: 688 Registered: Feb-06 | Maybe 60hz is the Fs of the speaker?? Not sure but just a guess. |
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Silver Member Username: J_baby15Kentucky Post Number: 689 Registered: Feb-06 | Oh yea. And sum of, such as the stock BOSE ones in my car, jus suggest you dont play below a certain freq. b/c it may damage the speaker, however, they still play that low just not clearly. |
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Gold Member Username: InsearchofbassPost Number: 4920 Registered: Jun-04 | ok thanks and by the way the fs is actually 67 hz in free air but plays down to 60hz |
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Silver Member Username: J_baby15Kentucky Post Number: 692 Registered: Feb-06 | Well i was jus throwin sum guesses out there man. Im not positive that is the answer, but more than likely its jus recommended not to play under 60hz. |
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Gold Member Username: BestmankindBTLUSA Post Number: 6569 Registered: Oct-05 | speakers are always capable of playing below their fs. why you may ask. that i cannot say. they just do. lol. sorry sean, i know this isn't the answer you are looking for. |
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Gold Member Username: Basshead86Try Google Post Number: 7737 Registered: Aug-05 | the Fs is just the speakers moving mass/suspension stiffness measurement. the speaker will play below Fs better with a higher Qts iirc. From CAC:
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Gold Member Username: Basshead86Try Google Post Number: 7738 Registered: Aug-05 | let me say it like this.....a subwoofer does not have an internal crossover...so it will play a 1hz tone. so will a tweeter, but it will blow so when you send a 50-60hz tone through a midbass speaker, depending on the brand, it won't sond very good, and will struggle to keep control of the VC...resorting in unlinear VC movements...aka distortion. |
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Gold Member Username: InsearchofbassPost Number: 4921 Registered: Jun-04 | thanks guys the answers do help ...esp....muddy's |
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Gold Member Username: Basshead86Try Google Post Number: 7741 Registered: Aug-05 | your welcome should be resulting*** in unlinear VC movements |
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Gold Member Username: BestmankindBTLUSA Post Number: 6571 Registered: Oct-05 | ok muddy we got the picture. show off. lol. just playig man. |
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Gold Member Username: Basshead86Try Google Post Number: 7743 Registered: Aug-05 | hahahahaha....nah, it is just that Fs is the one T/S param i got an*l about and wanted to know the most of. lol b/c i didn't understand it for the longest time. i still couldn't tell you what a lot of them were w/o looking at them first. but Fs is a very important oen to me  |
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Gold Member Username: MixneffectOrangevale, Ca. USA Post Number: 1137 Registered: Apr-05 | Also, keep in mind, transmission lines work different than a conventional box. Transmission lines or labyrinths work based on wavelengths verses net volume. Who knows, the length of the PVC tube may have been close enough for 1/4 wavelength of the frequency/(ies) you experienced gain. |
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Silver Member Username: Bass__monkeyLas Vegas, Nevada U.S. of A. Post Number: 173 Registered: Sep-06 | nice! well if the tube is just straight there are ALOT of anomalies there... in that tube the way the reflection reacts is based on the cone, power, parameters of the driver, hell just plain ol physics! shoulda kept awake in class. lol. but, the way the cone is shaped will ricochet all around the inside of the tube causing an echo effect and the driver itself plays certain frequencies differently against it's enclosure's response (stick any sub in the box u built it all sounds different...) anyway, a tube that is long WILL over exaggerate some frequencies over others. (when i was experimenting building a cube enclosure where the sub n port ALIGNED directly behind each other (port placed right behind the sub with varying distances) it over exaggerates tuning... that's why they use it in spl crx's... it EXAGGERATES! yes, it will blow ur mind, needless to say it was fun! also like what mixneffect listed, if it nears a length it's possible for a quarter wave TL. DIYers rule! |
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Gold Member Username: InsearchofbassPost Number: 4923 Registered: Jun-04 | well at 6 feet long with the sub on the end of the tube inverted of course....using the formula 1128 divided by 47 divided then by 4 for quarter wave you get 6 feet of tubing needed for a 47 hz transmission line tuning....and yet it played very very controlled at 20 hz....thought id do the math for the tline's actual tuning |
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Gold Member Username: InsearchofbassPost Number: 4924 Registered: Jun-04 | i made a mistake forgot i didnt convert the last figure to inches |
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Gold Member Username: InsearchofbassPost Number: 4925 Registered: Jun-04 | never mind blonde moment i did it right the first time |
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Gold Member Username: InsearchofbassPost Number: 4926 Registered: Jun-04 | I think im gonna build some of these for my home reciever and see how they do on music...I have 3 six foot pieces of 6 inch pvc |
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Gold Member Username: Basshead86Try Google Post Number: 7772 Registered: Aug-05 | i have never thought about that, but i could see how having the port opening right behind the subs pole vent could make things a bit wacky... |
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Gold Member Username: InsearchofbassPost Number: 4936 Registered: Jun-04 | http://www.t-linespeakers.org/projects/steve/index.html Thats the website above where I got this pic mine was mounted the oposite way of this pic...(mine was magnet out...which is fine as long as the sub is tightly sealed on the other side side)...this is the easy way to make a tline...check out the website to see more  |
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Gold Member Username: Basshead86Try Google Post Number: 7901 Registered: Aug-05 | looks like a futuristic sound weapon. lol |
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Gold Member Username: FrkkevinResonant Engineering..., Fort Worth... Fort Worth, ... Post Number: 1443 Registered: Nov-05 | almost makes me want to experiment with tweeters, toilet paper rolls, and home-made funnels from a coke bottle... ultra-sonic-high-pitch-"futuristic-sound-weapon" .. wait no longer.. its arrival is now.. what a crude reality |
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Gold Member Username: InsearchofbassPost Number: 4937 Registered: Jun-04 | LOL.....seriously though check out the weblink and youll get a better idea what they are doing...I was using 6 inch pvc but they are using sonotube |
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