t-line enclosure for focal polykevlar ? please!!!

scooby1 · 27th June 2005, 05:31 AM

hello there speaker junkies, i have been lucky enough to aquire two focal polykevlar 6.5"woofer and am hoping someone out there could tell me if a t-line is feasible. here are specs... thanks
fs 52hz
vas 16.1 L
Qts .39 Qes .41 Qms 7.41

Sd 124.7 cm2
x max 3.5
Re 5.8 ohms
sens 89.2db
i have been given one suggestion of line 63" at sd x1.
I am looking to make a folded line similar to pmc design.
cheers and thanks

Greg B · 27th June 2005, 05:44 PM

Offhand, I'd say those are more suited to a tower type bass reflex, AKA MLTL. Focal drivers tend to work well in these. For a time many of their kits used them. This is basically a stretched BR ~1m tall with a port at the bottom. The pipe action tends to pump up the midbass a bit - exactly where you'd typically have a dip in a too big BR with a lowish Q driver.

They might be OK in a 'pure' TL if you are using a high output impedance source, a SET tube amp for example.

The whole notion of Sd as a design parameter is pretty outmoded. Line volume depends on Vas etc. Definitely read through Martin King's TL site, www.quarter-wave.com.

GB

scooby1 · 28th June 2005, 06:47 AM

yes i think a BL or MLBL might be the go as it is my first project..i think it must me the design concept that excites me though, i have tried MJK mathcad and i dont think its working for me? plus i truly only got my first computer 2 mths ago!! very interested just lacking skills at this stage all responses are very welcome indeed

27th June 2005, 05:31 AM	#1
scooby1 diyAudio Member Join Date: Jun 2005 Location: vic aus	t-line enclosure for focal polykevlar ? please!!! hello there speaker junkies, i have been lucky enough to aquire two focal polykevlar 6.5"woofer and am hoping someone out there could tell me if a t-line is feasible. here are specs... thanks fs 52hz vas 16.1 L Qts .39 Qes .41 Qms 7.41 Sd 124.7 cm2 x max 3.5 Re 5.8 ohms sens 89.2db i have been given one suggestion of line 63" at sd x1. I am looking to make a folded line similar to pmc design. cheers and thanks

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27th June 2005, 05:44 PM	#2
Greg B diyAudio Member Join Date: May 2004 Location: Los Angeles, California	Offhand, I'd say those are more suited to a tower type bass reflex, AKA MLTL. Focal drivers tend to work well in these. For a time many of their kits used them. This is basically a stretched BR ~1m tall with a port at the bottom. The pipe action tends to pump up the midbass a bit - exactly where you'd typically have a dip in a too big BR with a lowish Q driver. They might be OK in a 'pure' TL if you are using a high output impedance source, a SET tube amp for example. The whole notion of Sd as a design parameter is pretty outmoded. Line volume depends on Vas etc. Definitely read through Martin King's TL site, www.quarter-wave.com. GB

28th June 2005, 06:47 AM	#3
scooby1 diyAudio Member Join Date: Jun 2005 Location: vic aus	yes i think a BL or MLBL might be the go as it is my first project..i think it must me the design concept that excites me though, i have tried MJK mathcad and i dont think its working for me? plus i truly only got my first computer 2 mths ago!! very interested just lacking skills at this stage all responses are very welcome indeed