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Old 17th March 2013, 01:19 PM   #101
xrk971 is offline xrk971  United States
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Quote:
Originally Posted by picowallspeaker View Post

Tremendous changements, uh?
Once you diverge from what's inside the disc...
properly: an infinitesimally little changement produces an infinite grade of dissociation from what's inside the disc.
What's inside the disc is axiomatically unknown
I have no idea what you are talking about here. Perhaps the general idea that mathematically, a change inside an integration boundary cannot be known, even though it causes a large change outside? In the case of a foam core speaker enclosure that vibrates, the effect can be estimated based on the difference between total output vs output from driver and vent.
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Old 17th March 2013, 01:34 PM   #102
xrk971 is offline xrk971  United States
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Quote:
Originally Posted by Philfr View Post
Here the results :
Jordan MLTL
Phil.
Nice result Phil. I agree that rear facing vent seems best in room boundaries.
Click the image to open in full size.

Which size vent did you end up with here in these sims?
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Old 17th March 2013, 01:58 PM   #103
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Quote:
Originally Posted by xrk971 View Post
I have no idea what you are talking about here. Perhaps the general idea that mathematically, a change inside an integration boundary cannot be known, even though it causes a large change outside? In the case of a foam core speaker enclosure that vibrates, the effect can be estimated based on the difference between total output vs output from driver and vent.
Sorry for mixing or going OT, no ,well, it's still in thread
I meant that everything should be done with the intention of having the maximal intensity perceived by the listener. Talking about the speakers and not the entire system or room, or even about the disc content, the goals are...
wait: what speaker ? We were talking about procedures .
The major issue is the 'covering effect' that happens during reproduction.
It's the sound originated by, somehow, somewhere that overimposes on the
original ( which is not known) one; we could know the amount of it, or verify
how much it can differ ....
So it's not that easy; sorry again to be so pedantic
We're not talking about a ceiling speaker at the supermarket, you know...those diabolic things that inject in your brain those stupid jingles.
I had in mind the answer why it could be nice to hear those things that you made in the cornu thread...but, yes, if referring to a 10cm driver left alone to guvern under avverse conditions, in storm and rain
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Old 17th March 2013, 03:21 PM   #104
Philfr is offline Philfr  France
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Rport is 3 cm..
Little dips and holes between 700 and 1000 hz is create by lenght of port.
With smaller value (under 14 cm), we have not, it's a straight line.
Phil.
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Old 17th March 2013, 06:42 PM   #105
xrk971 is offline xrk971  United States
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Quote:
Originally Posted by Philfr View Post
Rport is 3 cm..
Little dips and holes between 700 and 1000 hz is create by lenght of port.
With smaller value (under 14 cm), we have not, it's a straight line.
Phil.
Is Rport the radius or diameter of the vent?
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Old 17th March 2013, 07:09 PM   #106
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Quote:
Originally Posted by xrk971 View Post
Here is what I came up with:
16 liter vol with WinISD BR tuning at 44 Hz.
Accidental MLTL design gives based on assumed 40 in pipe and 6 in baffle width.

L=40 in
Width = 6.0 in
Depth = 4.0 in
Vent dia = 2.0 in (round)
Vent Length = 6.1 in (downward firing)
Zdriver= place at 13 in from top or near top ~5 in for good height close to ear.
Stuffing in top 26 in of line.
one thing i don't understand, how did you come to a 40 in line length? My calculation wd be much longer
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Old 17th March 2013, 07:17 PM   #107
Philfr is offline Philfr  France
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>> Is Rport the radius or diameter of the vent?
R is radius..
Phil.
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Old 17th March 2013, 08:35 PM   #108
xrk971 is offline xrk971  United States
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Practical consideration to get it higher up to ear level and not too long that it will tip over easily. Also, I have built them at 40 in before and it seems to work. It turns out to be about same as what others who designed it with MJK ended up using. If you make it too long, that is close to quarter wave length for fb, the mass loading will drive fb too low, below what driver may be able to do.
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Old 17th March 2013, 09:11 PM   #109
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bit confused, the line length or cabinet 40 inches in height (or both)? I would always 'fold' and the baffle can be angled by a degree or 2 if needed

I assumed a line frequency length just above the resonant frequency value of said drive unit was correct, same as a standard TL but maybe around 10% extra as its tapered/flared

Last edited by Bill poster; 17th March 2013 at 09:23 PM.
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Old 17th March 2013, 09:19 PM   #110
xrk971 is offline xrk971  United States
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You can fold but if you tune length close to just above fs of driver you do not need to mass load. The mass loading achieves both reduced line length and provides more filtering of output peaks and valleys by low pass filtering output from line. The length as I have said is mostly based on seeing other MLTL designs and their lengths.
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