TL vs Overdamped BR - Opinions?

H

hannibal

AK Member
Two things I don't have much experience with; and I'd like to hear
any opinions on their general similarities and differences as far as
their actual sound goes. Subjective and un-scientific as this is,
I'd love to hear from anybody that has listened to both. (Or be
steered to a thread on it that I've missed.)

What I'm out to build is a nice, no-subs-needed, 2 channel, music-
only home system with something like a single 12" or twin 10's @
side, most likely 3-way & tri-amped. Driver selection is pretty well
covered - what I need to decide is if it's worth the extra work to
scare up a TL design when I already have a nice design in hand for
overdamped BR. (The extra fab difficulty would not be an issue.)
I don't need stupid-deep subsonic HT rumble, just effortless, musical
bass. Any feedback is greatly appreciated.
 
Register to hide this ad
Hi,

It depends on the capabilities of your bass drivers. BR tuned low gives
a good compromise of bass versus cabinet size. TL's give the maximum
bass extension but are usually significantly larger, going round in circles
you could use bigger BR'd drivers in the same TL cabinet volume.

For bass driver volume displacement matters, area x excursion.

rgds, sreten.
 
sreten said:
Hi,

It depends on the capabilities of your bass drivers. BR tuned low gives
a good compromise of bass versus cabinet size. TL's give the maximum
bass extension but are usually significantly larger, going round in circles
you could use bigger BR'd drivers in the same TL cabinet volume.

For bass driver volume displacement matters, area x excursion.

rgds, sreten.
Click to expand...
How about passive system. My RTR's are quite amazing. 10" woofer which carries up to 2khz comfortably, yet provides ground shaking bottom end coupled with the passive. I like the musical sound better than BR (most sound boomy to me) and no port noise to deal with (though honestly I'm not sure I've heard port noise, just lucky?).

Others can chime it, but my understanding is you use the same cab calculations as you would a BR system. Or roughly that.
 
T-lines are more natural sounding then ported designs. I prefer aperiodic over ported designs. It all comes down to the drivers in properly designed and tested t-line enclosures. No different then comparing a 30$ tweeter to a 150$ tweeter. High compliance drivers preferred just as in ported designs. At first a listener that is used to the boom of ported designs might not think the bass is as deep with a t-line. Careful listening over time will reveal more detail in the recording due to the reduction of reflections on the rear of the cone. In ported and closed box designs the sound from the rear of the cone is reflected inside the box and creates distortion.
 
sm19422 said:
T-lines are more natural sounding then ported designs. I prefer aperiodic over ported designs. It all comes down to the drivers in properly designed and tested t-line enclosures. No different then comparing a 30$ tweeter to a 150$ tweeter. High compliance drivers preferred just as in ported designs. At first a listener that is used to the boom of ported designs might not think the bass is as deep with a t-line. Careful listening over time will reveal more detail in the recording due to the reduction of reflections on the rear of the cone. In ported and closed box designs the sound from the rear of the cone is reflected inside the box and creates distortion.
Click to expand...

Hi, a load of unfounded opinions that are all wrong depending on the case, rgds, sreten.
 
Copa1934 said:
How about passive system. My RTR's are quite amazing. 10" woofer which carries up to 2khz comfortably, yet provides ground shaking bottom end coupled with the passive. I like the musical sound better than BR (most sound boomy to me) and no port noise to deal with (though honestly I'm not sure I've heard port noise, just lucky?).

Others can chime it, but my understanding is you use the same cab calculations as you would a BR system. Or roughly that.
Click to expand...

For all intents and purposes BR and PR are one in the same.
 
If you can over come the cabinet complexity of the TL vs the PR then you are well onyour way to having an excellent potential for a bass platform. It may also a bit fickle with placement if you rear slot your design.

Local speaker mfg here in Ft Worth Tx, "Toby" built TL for years and I consider them standards of the design. Never heard one I did not like for their ultra smooth bass reproduction. Never boomy or weak and easily blending with upper drivers.

As for PR designs, I think Klipsch came as close as anyone getting that done well. The Forte and others are good examples.

If you get the chance do put an ear or two on a Toby design, even their older 6"x9" cone design was pretty good!
DC
 
dnewma04 said:
Probably a KEF driver?
Click to expand...

It's not a Uni-Q type driver, just a woofer. Not really sure who makes it.

X9.jpg


I know their subwoofer enclosures were a big deal back in the 90's They still make them, and their probably still pretty decent. I haven't heard one in so long I forgot what they sounded like, but I recall be impressed at the time.
 
Sreten not a load of unfounded opinions. I have been building and testing them since the early 1980's. Bud Fried was my mentor I live close to where he assembled and tested his speakers. What Bud did with his t-line enclosures and series circuit designs are world reknown by audiophiles. After the company was resold the second time they no longer sold kits and abandoned one of the most acoustically correct 3 ways I have ever heard. The proof is listening, and testing the same drivers in different enclosures which I have done. Kevin Blair's article in Speaker Builder 2-1994 design principles coincide to what Fried did. Fried and R. Wright expanded on Bailey's early designs. T-lines are an expanding sound source where ported designs are not.

http://www.scribd.com/full/14966584?access_key=key-mioyzl1d3eydoh4zj26
 
If I were to guess, I'd say that sreten's were more based on your criticism of other enclosure types. There are plenty of very natural ported enclosures just like there are natural and detailed TLs, AS, aperiodic, etc. I've heard a lot of TLs and some of them have been very impressive but none have convinced me they are the best option.
 
Great replies and much thanks, gang. Size doesn't worry me too much,
short of getting crazy big like some of those monster Polks back in the day.
As for BR, what I'm trying to learn about is not traditional BR
so much as overdamped BR designs specifically, which seem to be a
different critter. Information I've found so far is
patchy as to just how they compare to TL designs - or even sealed
cab - not only in terms of accuracy, but even just how they roll off the bottom.
I suppose there must be a thread somewhere that mentions a specific
bottom roll-off slope for ODBR, but I haven't seen it.

@sm19422:____________________________________________
"No different then comparing a 30$ tweeter to a 150$ tweeter."
*
All good.
The nature of my question invites apples/oranges comparisons
and subjective opinions too, and that's OK. As much as
anything else, I seek the listening
impressions of those that have listened to both TL and ODBR cabs.
____________________________________________________________
"T-lines are more natural sounding then ported designs. At first a listener that is used to the boom of ported designs might not think the bass is as deep with a t-line. Careful listening over time will reveal more detail in the recording due to the reduction of reflections on the rear of the cone. In ported and closed box designs the sound from the rear of the cone is reflected inside the box and creates distortion."
*
This summarizes just what tantalizes me about the concept.
_________________________________
"I prefer aperiodic over ported designs." - - - -
*
Now this is where
it gets interesting for me, because doesn't a good overdamped BR cab
design function more or less the same way as one with resistive vents?
Is my assumption wrong in this? Anyway what I'd 1st had in mind was to clone the ESS AMT 3
(I have all the dimensions), which is described by ESS as a "resistive bass-reflex" - (basically
"precision overstuffed", IOW).
Would this not be an aperiodic design, even though it's not done with resistive vents per se?
(Correct me if I'm wrong). Either way, I'd be glad to hear sm's take (or anyone else with an
opinion on the subject) on how aperiodic or ODBR cabs stack up to TL.

Anyway, the crux of the decision I'm trying to make is whether to clone
an AMT 3, or go the extra mile and build a TL cab under my mid-bass/
Heil combo.

I see other posters weighing in even as I compose this. Thanks to all.:ntwrthy:
I keep seeing the Toby in my wanderings through various TL 'sites and
forum threads. Never have heard one. Never heard a bad word spoken
of them either.
 
One point that can't be stressed enough is that the enclosure can only sound as good as the limitations of the driver. The Yahoo Transmission Line Loudspeaker Group has been a way to trade info among t-line builders. Some are world reknown for their research and contributions to the audiophile community. Many designers have used different formulas for designing them.
 
It's a well known fact that if you use a bunch of crappy drivers in a line array, you will achieve superior sound. Just look at a Parts Express buyout section. :)
 
Hey sm, LOVE the "Enough Rope" article @ your link. More enlightenment
and yet more things to ponder. ANNND there's things in there that dovetail
nicely with other things I've been thinking/wondering about, especially
regarding best ways to house a mid-bass driver. The 18" tube described
looks a lot like that in the likes of the IMF TLS 80 and the ESS AMT 3, for
instance. But ever since I first read ESS' literature
describing their tube as a "transmission line" I've been going "hmmmm..." -
and then this article describes using a real TL loading for mid-bass driver
like I'd been pondering. I'd been wondering how that would compare to
B&W's tapered tube or sphere-into-cone sub-enclosures. I'll be rereading
that article a few more times and looking a lot more closely at Fried products
to see what else I can learn.

Oh, good to know about the Yahoo TLG, too, thank you. :D Didn't know about
that, so I will be looking into it. I'll be sticking to drivers that are zippy
enough to blend well with the big Heil AMT's in the neighborhood of 2.3 K.
 
IF you can get a transmission line right I don't think anything can sound as nice but it takes many hours of trial and error. I have a set of Hiel or Ess cabs that a local reseller sold the speakers and tweeters out of. It takes a 10" woofer and I haven't found one that works at all volumes yet but at the right volume they really sound great.
 
Fried's C3L enclosure being a sloped front 7.5 degrees gives proper time alignment for crossover point. Line lenght is 80hz tuned to 60 hz by stuffing density. By changing stuffing density any 6.5 will work in this enclosure by changing stuffing density relative to driver parameters. Bud tried a wide variety of drivers in this enclosure. Carboneau, Focal, Vifa then used the custom made Gefco composite cones. He did the same with many of his sub enclosures. I took the original Model C 6.5" oem units and used them in the C3l enclosures and couldn't believe the wealth of detail I heard in the t-lines compared to the aperiodic enclosures. I have also used the Gefco drivers in the Fried lines. More links. Some have been removed for legal reasons. The person that owns these designs doesn't want them to be used by other people for profit.

http://www.imf-electronics.com/Home/fried
 
You must log in or register to reply here.
Back
Top Bottom