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Old 19th February 2013, 10:10 PM   #451
djk is offline djk
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"or ? "

I dislike isobaric.

I would rather run all four with a Linkwitz transform.

"Why not face the conus to each other like in a ripole"

Why not just run it like the Linkwitz woofer?

I like P-P, it sounds better. Sealed, vented, OB, take your pick.
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Old 19th February 2013, 11:56 PM   #452
kees52 is offline kees52  Netherlands
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Quote:
Originally Posted by djk View Post
"or ? "

I dislike isobaric.

I would rather run all four with a Linkwitz transform.

"Why not face the conus to each other like in a ripole"

Why not just run it like the Linkwitz woofer?

I like P-P, it sounds better. Sealed, vented, OB, take your pick.
I have still the push pull dipoles from linkwitz, she sound well, very low bass extension, a ripole I have never tryed, but hear not so good things about it on some places, a tapped horn maybe, I will try all, horns I did have for a long time, she are still for my ears the best, fast and dynamic, the dipole, no slam, but very open eary bass low efficienty and danger for the woofer (xmax damage).... I think still to go make a two 18 inch dipole sub. totally 2670 Sd give 86 dB 1 watt is acceptable, still xmax damage if not carefull, but the stiff membrane will help autocompress or how you call that...

Last edited by kees52; 19th February 2013 at 11:59 PM.
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Old 20th February 2013, 12:43 PM   #453
kees52 is offline kees52  Netherlands
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Oke I have make a 6th order highpassed PPSL and maybe we don't need the high pass as the slot have impact, how i don't now before I have build it.

I go drawn the box in sketchup.

The box is ex plenum 230 liters, I can do 200 liters then I have -3 dB 18 Hz.

It is for home use, not PA so I am curieus about how much hifi this is.

picture of the plenum this is the right way? but plenum needs the same width as the box? and depth just to fit speakers?

This ventel alignment is B6 with High pass filter.

thanks.
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Last edited by kees52; 20th February 2013 at 12:58 PM.
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Old 20th February 2013, 12:59 PM   #454
tinitus is offline tinitus  Europe
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Quote:
Originally Posted by kees52 View Post
... a 6th order highpassed PPSL and maybe we don't need the high pass as the slot have impact...
slot effect/impact is very interesting indeed, for this, and in general

but what do you mean by highpassed
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Old 20th February 2013, 03:14 PM   #455
kees52 is offline kees52  Netherlands
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Originally Posted by tinitus View Post
slot effect/impact is very interesting indeed, for this, and in general

but what do you mean by highpassed
with highpassed I mean this.

Vented Box with Active 2nd Order High-Pass Filter

This is a vented box with the addition of an active 2nd order (12 dB/octave) high-pass filter in front of the amplifier. The filter usually has a Q of about 2. The result of adding the active filter is a further extending of the bass response up to an octave below Fs and a 6th order or 36 dB/octave low-frequency cutoff rate.

When designed properly, this type of vented box can handle more power because of the protection afforded by the steeper cutoff rate. However, this advantage can be undone by higher excursion in the passband in some cases. Vented boxes with active 2nd order high-pass filters like the ones calculated in BassBox Pro are sometimes referred to as having a B6 alignment. This heralds back to the 6th order Butterworth alignment originally described by A. N. Thiele. However, BassBox Pro allows the user to control the filter parameters (Fx, Qx) and accepts a wider variety of drivers, resulting in response shapes that may not resemble a Butterworth shape.

Copyright 1992-98 by Harris Technologies, Inc.
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Old 20th February 2013, 03:24 PM   #456
kees52 is offline kees52  Netherlands
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As you see I cabn play with this filter, changing low end respons.

I try to make a line level high pass before the amplifier input.
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Old 20th February 2013, 07:48 PM   #457
djk is offline djk
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With a Qts=0.312 and a Q=2 filter at Fs=Fb=Faux the system will be a B6. Other values will be quite similar but technically be called a C6, and will have a small amount of ripple.

It may also be desirable to reduce the Q of the filter to allow for some 'room gain'. I used to build a system with a filter Q=1 at 30hz and it measured flat in a typical room even though the design called for a Q=2.
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Old 20th February 2013, 07:57 PM   #458
kees52 is offline kees52  Netherlands
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Hi djk I have still some question, I use two 330 Sd woofers and I get max 152 cm2 before the tunnel get to long now it is already 72.7 cm and so I have to go up on the back of the enclosure some say here do go not longer then 85 cm.

I can get port noise if to small, but 4 x 38 cm long is enough I hope.

Do someone has problems with boxpro 6 it looks that sometimes it do not update the calculations on my windows 7 64 bit pc maybe there is a bad version.

thanks all.
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Old 20th February 2013, 08:15 PM   #459
OscarS is offline OscarS  United States
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Originally Posted by weltersys View Post
Oscar,

DSL's TH-812 uses an in-line PP loading that probably would work better than the plenum you suggested.
Even if it did not work better, it would be a lot easier to build.
You're probably right, but this is for the trunk of a car where I need the most compact solution possible (for a tapped horn).
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Old 20th February 2013, 08:23 PM   #460
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Originally Posted by OscarS View Post
You're probably right, but this is for the trunk of a car where I need the most compact solution possible (for a tapped horn).
An in-line or side by side PP would be more compact than using a plenum.
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