Closed/sealed box design strategy

Tyimo · 27th February 2005, 10:49 AM

Hi!
I would like ask the experts about closed/sealed box design technics. What is the most prefered way:
-Butterworth (Qtc: 0.707)
-Bessel (Qtc: 0.577)
-Critically damped (Qtc:0.5)
What are the advantages of the closed ended TML boxes? (Like the Nautilus?)
What is the "best" closed box laudspeaker on Earth? :-)
Nowadays I can see most of time only vented designs. Why?

Greets:

Tyimo

richie00boy · 27th February 2005, 11:17 AM

There is no best design, it's all a matter of individual taste.

Lower Q sealed gives better transient response and group delay/phase at the expense of larger box and earlier roll-off.

Vented is popular because it gets lower cut-off and better efficiency, at the expense of transient response and group delay/phase. Box size is larger than closed, but not terribly so.

Different applications (sub, only main speaker, satellite etc.) require different approaches.

RJ · 27th February 2005, 03:29 PM

A test done on several Q points;
http://www.geocities.com/kreskovs/Box-Q.html

Watch out for room gain at a Q of 1.0....

mike.e · 28th February 2005, 10:50 PM

Quote:

Originally posted by RJ
A test done on several Q points;
http://www.geocities.com/kreskovs/Box-Q.html

Watch out for room gain at a Q of 1.0....

Hey that is rather interesting

Tyimo · 1st March 2005, 04:29 PM

Hi!
RJ thanks!
Interesting site!

Is there any rule of thumbs how to design a good closed end TML speaker?

RJ · 2nd March 2005, 07:59 PM

Is there any rule of thumbs how to design a good closed end TML speaker?

I'm guessing the L in TML stands for Transmission Line.
Here's a site that can explain it.
http://www.t-linespeakers.org/design/classic.html

Tyimo · 3rd March 2005, 04:57 PM

Hi RJ!

Thanks, I know this site already and there is nothing about closed end TML speaker design. :-(
I know that the closed box geometry need to absorb the back waves, but what about the TML 1/4 frequencies? It will be stronger?

Tyimo

27th February 2005, 10:49 AM	#1
Tyimo diyAudio Member Join Date: Nov 2002 Location: Hungary	Closed/sealed box design strategy Hi! I would like ask the experts about closed/sealed box design technics. What is the most prefered way: -Butterworth (Qtc: 0.707) -Bessel (Qtc: 0.577) -Critically damped (Qtc:0.5) What are the advantages of the closed ended TML boxes? (Like the Nautilus?) What is the "best" closed box laudspeaker on Earth? :-) Nowadays I can see most of time only vented designs. Why? Greets: Tyimo

27th February 2005, 11:17 AM	#2
richie00boy Did it Himself diyAudio Member Join Date: Nov 2003 Location: Gloucestershire, England, UK	There is no best design, it's all a matter of individual taste. Lower Q sealed gives better transient response and group delay/phase at the expense of larger box and earlier roll-off. Vented is popular because it gets lower cut-off and better efficiency, at the expense of transient response and group delay/phase. Box size is larger than closed, but not terribly so. Different applications (sub, only main speaker, satellite etc.) require different approaches. __________________ www.readresearch.co.uk my website for UK diy audio people - designs, PCBs, kits and more

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27th February 2005, 03:29 PM	#3
RJ diyAudio Member Join Date: Oct 2004	A test done on several Q points; http://www.geocities.com/kreskovs/Box-Q.html Watch out for room gain at a Q of 1.0....

1st March 2005, 04:29 PM	#5
Tyimo diyAudio Member Join Date: Nov 2002 Location: Hungary	Hi! RJ thanks! Interesting site! Is there any rule of thumbs how to design a good closed end TML speaker?

2nd March 2005, 07:59 PM	#6
RJ diyAudio Member Join Date: Oct 2004	Is there any rule of thumbs how to design a good closed end TML speaker? I'm guessing the L in TML stands for Transmission Line. Here's a site that can explain it. http://www.t-linespeakers.org/design/classic.html

3rd March 2005, 04:57 PM	#7
Tyimo diyAudio Member Join Date: Nov 2002 Location: Hungary	Hi RJ! Thanks, I know this site already and there is nothing about closed end TML speaker design. :-( I know that the closed box geometry need to absorb the back waves, but what about the TML 1/4 frequencies? It will be stronger? Tyimo

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