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TL vs Overdamped BR - Opinions?

Bondo? I'm not sure I want to know.:headscrat
Love your burn-barrel. Say, if I happen across any Bose...

sm, again with the killer link. That should keep me out of mischief for
awhile. Good stuff. As was your description of the C3L. More to think
about.

@sm19422:_______________________________________________________
"...and couldn't believe the wealth of detail I heard in the t-lines compared to the aperiodic enclosures."

OK good, that clarifies things. It was obvious you prefer the TL over aperiodic, but I wasn't sure by how big a margin.

Best I can do till I learn more about the AMT
3 cabinet is assume that it's about on a par with/equivalent to aperiodic.
Unless somebody out there knows different. From what little I've seen
about ODBR, I've seen it compared to TL, to sealed cab, that it rolls off
3rd order... IOW, not exactly getting a clear picture on that. :dunno:
If anybody knows of a definitive thread on the subject... :D
 
hannibal said:
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.
Click to expand...

The one nice thing about transmissions lines, that will complement the Heil, is the excellent transient response. The problem with many lower cost tuned port/passive systems is while the have loud(er) bass, the bass tends to be a bit sloppier and not as tight as a TL or sealed system.
The AMT3 came in 2 versions, the early sealed model, and the later ported version.
The ported version was in part to get more bass 'volume' out of the system, more efficency, at the price of tighter, 'quicker', more detailed bass, and superior transient response.
After experimenting with the Eminence 1040SF's in my AMT3's I have found they work much better with the port sealed. You sacrifice some efficiency, and a slight amount of output, but with the gentle roll off, it's hard to tell really.
The 1040's are a driver that by it's spec should work well in both types of systems-the problem when you use 2 of them, you really need both-2 ports and around a 5 cubic ft enclosure to maximize the ported performance, and prevent any midbass/ impendence peaks.
With the fully stuffed ported enclosure-allot of this varies on how well and evenly you have the stuffing distributed, and how much is by the port etc-as this makes alot of difference in the ported state, very sensitive.
With a sealed enclosure you only need 2.7 cu ft-the bare AMT3 cabinet being 2.5 (with tube-no drivers or braces) so you are achieving close to the ideal qtc at around .707- perfect!
The 1040SF also has a huge 9xmax that make it more then ideal for being sealed.
The performance of the woofer sealed is more then excellent-it's outstanding! The detail is now on par with the Heil-and integrates darn near perfectly. The way these woofer pressurize the listening space can really give one goose bumps. I was just listening to the Cars-All Mixed Up-and the bass detail-well I forgot how good the bass line were in this song-the little details now really stand out. When need be these sealed woofer will thump your chest in a way the ported versions couldn't-they would more or less hum along.
In the sealed state, one really need to make sure the cainet is well sealed, and I would highly recommend running a brace between the woofer openings-similiar to the one I have posted:http://www.audiokarma.org/forums/showthread.php?t=361605
The stock amount of stuffing is fine, right around 1.3 lbs per cu ft. I would be careful about too much damping, experiement.
Too much damping can squeeze the life out of speakers. I just use the stock stuffing, along with some foam on the rear baffle. I also added some addition screws to the inner and outer cabinet, from the inside.
Sealing th port is easy-if it's the 2.5 mail tube versions, I just used some plastic ends form Uline, and applied some damping material to them, and sealed them to the tube with some silicone.
In the sealed state a 150wpc amp I think would be minimum, but my little 100wpc H/K amp drives them fine and they get plently loud- but the AMT3's-ported, sealed-stock woofers or not can suck up some power easily, as the the ESS AMT's have that uncanny abilty to get louder and louder with no distortion, and your into clipping before you know it. Keep the AMT Heil fused and you won't have any problems-the smaller unfused Heils are another story-but if you add a fuse to these you fine.
If your stuck on the TL-try to fine the specs on the AMT tower-as this used a single 10" woofer-and you could easily add a mid/Alpha 6A to this witha box under the Heil.
The 1040SF would be a excellent TL driver-these woofers when used correctly are truly awesome, and a real bargin @$79 IMHO- and even better with the OCS discount.
Here is another AMT3 variation to wet Heil appetite.
http://www.audiokarma.org/forums/showthread.php?t=329593&highlight=custom+monitor+elites

By the way- if anyone has 1040'ed AMT3' that are ported, and want's to play with them sealed, I have some extra plastic caps (100 min order).
After all this experimetation, I think I have finally found another key to integrating the Heil to other drivers.
Using a sealed midbass/transition driver, but now also using a highly efficient large x-max woofer in a sealed enclosure so it's transient response is now on par with the Heil-try it the improvements are outstanding!!
 
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Martin has done a great service for providing software programs for the amateur to design t-lines. I have been in contact with users of his designs that have done designs for some of my Fried drivers specifically designed fot t-lines. i am also a member of his Yahoo Group. His works have made it possible for many people to come one step closer to the sound of a live performance in their listening areas. Enjoying the music and trading info by learning from each others experiences is what it should be all about.
 
@frperdurabo:_________________________________
"You might want to check out Martin King's work at..."

Thanks for that, I can see I'm going to be reeeeeal busy plumbing the
depths of all these links. If I don't resurface in 3 weeks, send in a
rescue crew. :D

'Mojo, wassup? I always appreciate your clarifying perspective. That's
a helpful overview and useful details along with.
_______________________________________
"The 1040SF would be a excellent TL driver..."
*
Been wondering about that, was on the verge of asking you in fact.
Good to know.
________________________________________________________________
"If your stuck on the TL-try to fine the specs on the AMT tower-as this used a
single 10" woofer-and you could easily add a mid/Alpha 6A to this with a box under the Heil."
*
Exactly one of the things that had crossed my mind. I saw a good diagram
of it in some old ad copy on a sweet site some German (I think) guy has up.
Cactus Bob posted a link to it, I can re-post here if anybody wants.
I'd even thought of making it double-wide or 2-sided and squeezing in the
both 1040's I'd originally intended for a '3' clone. One thought among many.

Your finding happiness with the cab sealed back up also gives me a
clearer picture of how the original ESS ODBR design works compared to
sealed. This tips me yet more towards TL (and all that extra work), :dammit:
as I've never been able to love the sealed cab sound myself,
but yet I want a lifelike, tight, un-distorted bass.
Different gear for different ears, no?
______________________________________________
http://www.audiokarma.org/forums/sho...monitor+elites
*
Long had that and the cab brace link bookmarked. I know
when I go veneer shopping I'm going to print those images
out and say: I wanna make it look like THIS! What beautiful
grain pattern. (Sonus Faber eat your heart out.)
 
The particular issue with the Heil AMT and it's woofer is that there are few woofers than can get high enough in frequency in a two-way alignment and maintain a good transient speed in the lower end (enough to keep up with the AMT). I know of one user that has a two-way Heil setup but he uses a woofer that is no longer in production.
I use the AMT with a midrange horn driven by a compression driver so it's transient speed is close. The AMT is crossed over quite high (from 7khz -->9khz, depending on my experimentation) Under these is a 15" Altec woofer in an MLTL alignment. I like the MLTL better than the original BR cabinet because it removes the hump in the lower frequencies and delivers a very mild rolloff to the nether regions. The tradeoff is that it requires a large cabinet, 16 cu. ft.. If I was looking to rebuild the Heil cabinet and bottom end, I'd be looking for a quality woofer that will mate well with the other drivers and the enclosure could be any of the three discussed. It sounds like you are not liking the vented cabinet so the TL might be your choice. Good luck with the Heil redo!
 
The TLs in the Fried Model H made some of the best bass I've heard. The TLs in the big IMFs made some of the worst. Execution trumps dogma.
 
westend said:
The particular issue with the Heil AMT and it's woofer is that there are few woofers than can get high enough in frequency in a two-way alignment and maintain a good transient speed in the lower end (enough to keep up with the AMT). I know of one user that has a two-way Heil setup but he uses a woofer that is no longer in production.
I use the AMT with a midrange horn driven by a compression driver so it's transient speed is close. The AMT is crossed over quite high (from 7khz -->9khz, depending on my experimentation) Under these is a 15" Altec woofer in an MLTL alignment. I like the MLTL better than the original BR cabinet because it removes the hump in the lower frequencies and delivers a very mild rolloff to the nether regions. The tradeoff is that it requires a large cabinet, 16 cu. ft.. If I was looking to rebuild the Heil cabinet and bottom end, I'd be looking for a quality woofer that will mate well with the other drivers and the enclosure could be any of the three discussed. It sounds like you are not liking the vented cabinet so the TL might be your choice. Good luck with the Heil redo!
Click to expand...

This is exactly what I found with the 1040Sf in the AMT3 cabinet.
When you look at the original design of the speaker, and perhaps when Nelson Pass was involved-the cabinet was sealed-not vented.
Using some basic speaker design sofware-the 1040Sf's specs-with 2 woofers are almost perfect with the volume of the AMT3 enclosure.
Rick @ OCS had these designed with ESS speakers in mind-with modern improvements. But they work much better when sealed, as possibly the O.E. woofer-which I may try.
The advantage the 1040SF has over the O.E ESS woofers is that it's more sensitive-perhaps a slightly softer suspension, and the 9 xmax is way more then the O.E.s- so you can handle more power with out damage. It also can deal with being sealed without losing much output at all.
The disadvantage is that is has more of a pronounced hump when vented then the O.E. due to the lack of volume in a 2 woofer configuration, among other things.
I jus picked up another spare Great Heil, and a couple Alpha 6A's, and may save these for a TL AMT3 design the future-use the AMT3 crossover, and perhaps the AMT Tower T/L layout.
 
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I never heard the model H or T. The Model O were the first t-lines I heard in 1980. . The O and Sm sub were their replacements. The O 4 which is 36 1/2 " tall by 23 1/2"' deep using 1" thick high density particle board is more room friendly then the H or T model. Having the driver raised up higher from the floor is more acoustically correct with having the satellites right above the sub. They are a real challenge to build and well worth the effort. The crossovers are expensive in all of the subs since they require large value air core inductors in 14 gauge wire. The Model T was crossed over higher in frequency then the Model O. Solen has the best price in large value inducors.
 
hannibal said:
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.
Click to expand...

What does "BR" stand for? I have never heard the term.

-k
 
ken kantor said:
What does "BR" stand for? I have never heard the term.

-k
Click to expand...

It threw me off too, but I think it stands for "Bass Reflex". I had to think about it for quite a while before I came up with that, which I think, but don't know for sure, is it.
 
Oh boy, are you guys in for some alphabet soup if this thread keeps going.
Yes BR for Bass Reflex is a pretty common consensus
I write ODBR when I get tired of writing out OverDamped Bass Reflex
TL is common for Transmission Line
And then with hybridized TL (or mongrelized some would say), the fun really begins:
Like MLTL, Mass Loaded Transmission Line (my best take on that, FWIW, is,
kind of a regular TL firing into a ported box - and I make NO claims there's
not a better interpretation - I'm a noob to the whole TL & variants thing)
I assume you know about the most important T&S (Thiele & Small) parameter:
WAF (Wife Acceptance Factor) - an invert function of WUAF, or
Wife Un-Acceptance Factor, which is DEFINITELY measured in dB.
Or so I've been told. :D
 
@ Tom Brennan:_______________________________________________
The TLs in the Fried Model H made some of the best bass I've heard. The
TLs in the big IMFs made some of the worst. Execution trumps dogma.
*
Love it. Useful feedback, puts things in perspective, and best of all,
NO MATH!! However, that is one SCARY avatar. :yikes:
 
It is nice to see a post from Ken. I have read his contributions to loudspeaker design in Speaker Builder a long time ago. I forgot to mention Solen is the only company that offers off the shelf really large values of inductors. I was surprised to see they offer a 30mh value inductor in 14 gauge. I would like to see the crossover that is used in. Perhaps a t-line that crosses over at 43hz in 8ohms.
 
89grand said:
It threw me off too, but I think it stands for "Bass Reflex". I had to think about it for quite a while before I came up with that, which I think, but don't know for sure, is it.
Click to expand...

Damn, I need sleep if couldn't figure that one out....

-k
 
hannibal said:
Oh boy, are you guys in for some alphabet soup if this thread keeps going.
Yes BR for Bass Reflex is a pretty common consensus
I write ODBR when I get tired of writing out OverDamped Bass Reflex
TL is common for Transmission Line
And then with hybridized TL (or mongrelized some would say), the fun really begins:
Like MLTL, Mass Loaded Transmission Line (my best take on that, FWIW, is,
kind of a regular TL firing into a ported box - and I make NO claims there's
not a better interpretation - I'm a noob to the whole TL & variants thing)
I assume you know about the most important T&S (Thiele & Small) parameter:
WAF (Wife Acceptance Factor) - an invert function of WUAF, or
Wife Un-Acceptance Factor, which is DEFINITELY measured in dB.
Or so I've been told. :D
Click to expand...

Sounds like a good thing for a sticky....

-k
 
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