1/8 wave transmission lines?

Bill poster · 13th December 2010, 12:56 PM

I understand that quarter wave is normally the way to go, but space restrictions for my cabinet design means that I am considering an 1/8 wave TL (using the CSS SDX7) --

what are the differences between 1/8 and 1/4 in performance terms?
would it ultimately offer any real advantages over a BR cab?

Cheers

Will

MJK · 13th December 2010, 01:15 PM

Quote:

Originally Posted by Bill poster

I understand that quarter wave is normally the way to go, but space restrictions for my cabinet design means that I am considering an 1/8 wave TL (using the CSS SDX7) --

what are the differences between 1/8 and 1/4 in performance terms?
would it ultimately offer any real advantages over a BR cab?

Cheers

Will

There is no such think as a 1/8 wavelength TL. Sizing the length based on 1/8 of a wavelength will produce a 1/4 wave TL with a tuning frequency twice as high.

Martin

Scottmoose · 01:43 PM

Martin beat me to it (good to see you around BTW Martin).

There's no such thing, as he says. All other things being equal, you'll just double the pipe Fo.

Bill poster · 13th December 2010, 01:24 PM

Thats told me then! Thanks Martin for clearing that up- I saw a mention on another thread but nothing else on google. btw What kind of line do Bose use in their compact systems?

Scottmoose · 13th December 2010, 01:42 PM

A relatively long, heavily folded and very probably sub-optimal 1/4 wave pipe.

speaker dave · 13th December 2010, 01:55 PM

Since most TL designs are heavily damped, does the length matter as much? Seems like one of the old (and discredited) vented box notions of "tune the box to the woofer resonance".

David S.

Bill poster · 13th December 2010, 01:57 PM

Cheers scottmoose, sub optimal meaning the cross section of the line I guess.

Volenti · 13th December 2010, 02:41 PM

Quote:

Originally Posted by speaker dave

Since most TL designs are heavily damped, does the length matter as much? Seems like one of the old (and discredited) vented box notions of "tune the box to the woofer resonance".

David S.

The old and discredited notion is that heavy damping makes the line appear longer (even if it might make it sound subjectively better)

The length, area and (if used) taper still matter.

Scottmoose · 13th December 2010, 02:59 PM

Quote:

Originally Posted by Bill poster

Cheers scott, sub optimal meaning the cross section of the line I guess.

I rather suspect it's the whole lot rather than just the line CSA.

mashypie · 13th December 2010, 03:26 PM

Hello,

I asked a similar q about would doubling the length of the line result in a 1/2 wave resonator...

Scottmoose posted some useful links about 1/4 and 1/2 wave resonators on the 2nd page if you're intersted in the theory behind it - helped me understand what I was talking about a lot more!!

Which would sound better?

But essentially a TL will always be a 1/4 wave resonator, no matter what its length

13th December 2010, 12:56 PM	#1
Bill poster diyAudio Member Join Date: Jun 2008 Location: London	1/8 wave transmission lines? I understand that quarter wave is normally the way to go, but space restrictions for my cabinet design means that I am considering an 1/8 wave TL (using the CSS SDX7) -- what are the differences between 1/8 and 1/4 in performance terms? would it ultimately offer any real advantages over a BR cab? Cheers Will

13th December 2010, 01:23 PM	#3
Scottmoose diyAudio Member Join Date: Mar 2005 Location: UK	Martin beat me to it (good to see you around BTW Martin). There's no such thing, as he says. All other things being equal, you'll just double the pipe Fo. Last edited by Scottmoose; 13th December 2010 at 01:43 PM.

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13th December 2010, 01:24 PM	#4
Bill poster diyAudio Member Join Date: Jun 2008 Location: London	Thats told me then! Thanks Martin for clearing that up- I saw a mention on another thread but nothing else on google. btw What kind of line do Bose use in their compact systems?

13th December 2010, 01:42 PM	#5
Scottmoose diyAudio Member Join Date: Mar 2005 Location: UK	A relatively long, heavily folded and very probably sub-optimal 1/4 wave pipe.

13th December 2010, 01:55 PM	#6
speaker dave diyAudio Member Join Date: Nov 2009 Location: Toronto	Since most TL designs are heavily damped, does the length matter as much? Seems like one of the old (and discredited) vented box notions of "tune the box to the woofer resonance". David S.

13th December 2010, 01:57 PM	#7
Bill poster diyAudio Member Join Date: Jun 2008 Location: London	Cheers scottmoose, sub optimal meaning the cross section of the line I guess.

13th December 2010, 03:26 PM	#10
mashypie diyAudio Member Join Date: Nov 2010	Hello, I asked a similar q about would doubling the length of the line result in a 1/2 wave resonator... Scottmoose posted some useful links about 1/4 and 1/2 wave resonators on the 2nd page if you're intersted in the theory behind it - helped me understand what I was talking about a lot more!! Which would sound better? But essentially a TL will always be a 1/4 wave resonator, no matter what its length

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