TL nut case

[dbaudio]

Hey yuall,
I don't see any TL builds with the terminus next to or close to the drivers.
I wonder, is it because the driver (Fs) quarter wave length will be out of phase with the line (Fo) tuned to a different Hz. This could cause some cancellation rather than enforce the bass end. The mids I know would mostly be cancelled. If the enclosure is a folded line you could end up with this close picture.... which would be more practical as far as the front grill size.

[Charles Darwin]

On mine the terminus is directly above the driver.
Didn't notice or measure any problems, mids aren't a problem as I cross them at 175Hz.

[dbaudio]

Thanks for info, is yours a bass TL? I wasn't clear on referring to the fill stuff suppression of the mids, leaving mostly the bass at the terminus. Use to be that the 1/4
wave was tuned to the Driver Fs, now most are shifting to the Line Fp; for good reason
????

[dbaudio]

On another TL note: I did some checking using the Shultz Alfa TL artical AE 8/03, where he used Augspurgers align tables SB 4/00 to formulate graphs. I found a large difference for the line volume Vp calc.... almost a factor 3:1 > over the Augs table calc. Anyone know if Shultz has made any corrections to his formulations?

[GM]

Originally Posted by dbaudio

I don't see any TL builds with the terminus next to or close to the drivers.
I wonder, is it because the driver (Fs) quarter wave length will be out of phase with the line (Fo) tuned to a different Hz.

Build convenience and/or located to maximize boundary loading, nothing more. The pioneers of audio's extensive research concluded that a vented alignment's output should be as close as practical to the driver's for max acoustical gain, to the point of initially designing some drivers with the vent being an extension of the driver's mounting frame, i.e. the driver is suspended in the vent and the driver mounted in the mouth of BLHs just above its acoustical vertical axis.

That said, not a good plan from a response accuracy POV when long vents are required unless you're planning to damp them same as a TL, though Onken aficionados will debate the point .

GM

[GM]

Originally Posted by dbaudio

On another TL note: I did some checking using the Shultz Alfa TL artical AE 8/03, where he used Augspurgers align tables SB 4/00 to formulate graphs. I found a large difference for the line volume Vp calc.... almost a factor 3:1 > over the Augs table calc. Anyone know if Shultz has made any corrections to his formulations?

Not that I'm aware of nor are any required based on my own 'adventures' in TL design. I never got around to comparing these two or even to MJK's Classic Alignments, but with TLs there's no hard n' fast rules WRT net Vb beyond what is required to get the desired nominally flat gain BW out of a sound system at 'x' stuffing density, so apparently they had somewhat differing performance goals.

GM

[dbaudio]

Thanks, do you know if R Shultz is available for comment?

[GM]

You're welcome! Don't know, PM him or search other forums for 'exolinear': http://www.diyaudio.com/forums/members/exolinear.html

GM

[planet10]

[QUOTE=dbaudio;2593335]
I don't see any TL builds with the terminus next to or close to the drivers.

You aren't digging deep enuff?





These are an end-loaded TL, in many case use of a driver offset will make it hard to simply fold the line such that the terminus is adjacent to the driver.

dave

[dbaudio]

Nice design, way to go. What driver do you use? Looks like a large full range.
They also have to look good to stay in the wifeys living room.