1/4 wave, 1/2 wave, full wave? - Home Theater Forum and Systems - HomeTheaterShack.com

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post #1 of 19 Old 12-08-08, 05:25 PM Thread Starter
 
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1/4 wave, 1/2 wave, full wave?

I would guess a "full wave" TL/horn/what have you would be out of phase and cancel out? So is there a such thing?
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post #2 of 19 Old 12-09-08, 04:22 PM
 
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Re: 1/4 wave, 1/2 wave, full wave?

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kryptonitewhite wrote: View Post
I would guess a "full wave" TL/horn/what have you would be out of phase and cancel out? So is there a such thing?
Every TL and horn is a 1/2 wave device, one octave up from the 1/4 wavelength frequency. Just like with a reflex cab port output from the TL terminus is way down an octave above Fp, and if the pipe is properly stuffed is inconsequential. With a rear loaded horn a 1/2 octave dip is intrinsic, and is the major flaw of the design in a fullranger. A well designed rear loader sub places the dip above the passband where it can't pose a problem.
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post #3 of 19 Old 12-09-08, 05:38 PM Thread Starter
 
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Re: 1/4 wave, 1/2 wave, full wave?

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Bill Fitzmaurice wrote: View Post
Every TL and horn is a 1/2 wave device, one octave up from the 1/4 wavelength frequency. Just like with a reflex cab port output from the TL terminus is way down an octave above Fp, and if the pipe is properly stuffed is inconsequential. With a rear loaded horn a 1/2 octave dip is intrinsic, and is the major flaw of the design in a fullranger. A well designed rear loader sub places the dip above the passband where it can't pose a problem.
Thank you Bill, i've been impatiently waiting for an answer to that...it's going to take me a bit to obsorb a lot of that info.


Every horn is a 1/2 wave device...makes sense to me thus far... one octave up from the 1/4 wavelenght feequency...I'm lost.

So let's start with a 10Hz device, as my other thread implies that as a good fantasy. 1 octave up being 20Hz. So 1/2 wave is 10Hz, and 1/4 is 20, and 8th would be 40??

What is a reflex cab port? Some day when i have more time I'll Google all this, but if you could give me a summation, that would be great.

Fp, frequency or port? lol... just a guess... I'm assuming something like Fb

Thanks!
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post #4 of 19 Old 12-09-08, 07:19 PM
 
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Re: 1/4 wave, 1/2 wave, full wave?

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So let's start with a 10Hz device, as my other thread implies that as a good fantasy. 1 octave up being 20Hz. So 1/2 wave is 10Hz, and 1/4 is 20, and 8th would be 40??


Thanks!
The other way around.
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post #5 of 19 Old 12-10-08, 05:44 AM Thread Starter
 
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Re: 1/4 wave, 1/2 wave, full wave?

So at 1/2, 1/4, 18th, 16th... I assume there are peaks and dips, ripples, and such
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post #6 of 19 Old 12-10-08, 07:37 AM
 
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Re: 1/4 wave, 1/2 wave, full wave?

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So at 1/2, 1/4, 18th, 16th... I assume there are peaks and dips, ripples, and such
Not necessarily. Well designed TLs and horns are ripple free, though ripple free horns tend to be very large. But with the EQs now available ripple is no more a concern than a room mode, so reasonably sized horns are quite practical.
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post #7 of 19 Old 12-10-08, 04:53 PM Thread Starter
 
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Re: 1/4 wave, 1/2 wave, full wave?

I know everything is a matter of opinion, but it seems to me if $$$ were unlimited, as well as space and such, these would be the way to go.
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post #8 of 19 Old 12-11-08, 07:38 AM
 
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Re: 1/4 wave, 1/2 wave, full wave?

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I know everything is a matter of opinion, but it seems to me if $$$ were unlimited, as well as space and such, these would be the way to go.
Horns are considerably less expensive than direct radiators, as they get far better results per driver. My 8 cubic foot HT sub is loaded with a $35 eight incher, and goes as low and loud as SHMBO will tolerate. Commercial horns are expensive due to their high labor costs to build. That's not a factor in the DIY realm.
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post #9 of 19 Old 12-11-08, 09:16 AM
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Re: 1/4 wave, 1/2 wave, full wave?

Shmbo?




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post #10 of 19 Old 12-11-08, 10:06 AM
 
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Re: 1/4 wave, 1/2 wave, full wave?

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Shmbo?
Oops, SWMBO.
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