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Ideas for Updated Advent Library Section


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Hello all,

I'm readying a major update to The Classic Speaker Pages. I could use help in two areas as I prepare the new Advent section:

1.) A concise 1-2 paragraph biography on Advent

2.) Ideas on how (if) I can better organize the various classic Advent products

I am going to post a similar message in the other forums and will be pinning this topic in each. I realize we already have some bios in the Library, but I want to take a shot at a new bio that all visitors to the Advent section will see when they enter.



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There are a couple of forum participants that seem more than capable of writing a nice bio of the line.

As for the organization I would suggest a chronological index of links to individual pages pertaining to each speaker and it's permutations. With images of course.

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  • 12 years later...

I am interested in the lineage of the LARGE ADVENTS

Here is what I know... and it needs additional detail added



There are four basic model updates in the evolution of the Large Advent speaker:
- Original Large Advent (LA) - designed and introduced in 1969, and was simply named "The Advent Loudspeaker" when it was their only model. (The Layered "Fried Egg Tweeter")
- New Large Advent (NLA) - This was a major update to the original design. (The NEAT "Fried Egg Tweeter")
- Advent 5002 - The tweeter was updated to a black poly dome type, first by Advent then by Advent/Jensen.  Note that the 5012 is a real wood version of the 5002.
- Advent 25th Anniversary Limited Edition Speaker - essentially a reissue of the 5002/12.


Where does the The "Fried Egg" "Advent/1" and the "Advent 1" fit in?

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3 hours ago, Woofer-01 said:

I am interested in the lineage of the LARGE ADVENTS

Here is what I know... and it needs additional detail added

Very informative thread here:  https://audiokarma.org/forums/index.php?threads/identifying-your-advent-loudspeakers.126376/

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We can learn a lot by what is common and not, between them all:

1.  41-42 Hz closed box resonance (Fc) which is roughly low E on a bass guitar

2.  Closed box Q (Qtc) of about .8 - .85 ish which makes the half space response less than 3 dB down at Fc

3.  The OLA and NLA had only about 3mm theoretically linear Xmax (one way) and a huge Xmech of about 13mm.

    We can compute an overload headroom as 20 log(13/3)  = 12.7 dB of overload headroom.

4.  The OLA voice coil former is a very rugged brass/bronze looking type.  The later versions had and aluminum type.

5.  The tweeters are just OK, the NLA tweeter has an input impedance that is too low.  If they were voiced less hot

   with more resistance in series then they might work good enough.

6.  The Jensen design keeps the Advent bass (42 ish Fc and .8 ish Qtc, not sure if Xmax changed) but the 

  crossover voicing is not as good IMO.

7.  They all need baffle step compensation to sound truly HiFi IMO.

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  • 9 months later...

1. My name is Andy Kotsatos.  I collaborated with Henry Kloss on the Original Large Advent (OLA).  Henry designed the drivers, the unique woofer and tweeter, and I did the voicing of the speaker.  On the models that followed, Henry continued to determine the drivers, and I did the voicing of the Smaller Advent, the Advent 2, and Advent 3.  The New Advent (NLA) and Advent/1 were completely my designs.  More on those below.

In the OLA Henry chose a standard 12 inch basket frame because he wanted the woofer cone deeper than could be accommodated in a standard 10 inch frame, which required the use of the masonite ring spacer to the edge of the basket.  He recessed the front baffle to provide sufficient space for large woofer excursions and projected the tweeter forward from the woofer mounting surface to minimize reflections from the front edge of the cabinet.  To properly baffle the tweeter he added the square masonite panel that in conjunction with the grill panel provides a continuous mounting surface for the tweeter.  If you listen to the OLA (and the Smaller Advent) without the grill panel, they sound brighter because of destructive and constructive reflections for the main baffle board.  Both the OLA and Smaller Advent sound best with the grill panels installed.

2. The New Advent Loudspeaker (NLA) and Advent/1 were my designs, which is why Henry's name is not on the back of the speakers.  I wanted to move the front baffle forward to eliminate reflections from the cabinet "frame" around the drivers, and to improve the baffling of the tweeter so that the speaker would sound the same with the grill panel on or off.  To do that required totally new new basket designs.

The new woofer basket recessed the cone so that it would not hit the grill panel on large excursions and eliminated the need for the masonite ring. The new tweeter basket enabled mounting the tweeter flush with the cabinet baffle so that the speaker would sound the same with or without the grill panel.  Being shallower, the new basket permitted shortening the voice coil former thereby lowering mass and increasing efficiency.  And the New Advent tweeter was the first to ever use ferrofluid cooling.  

The moving parts of woofer remained the same as in the OLA.  The surround is inverted so that it projects forward.  Otherwise all the moving parts are identical to the Original Advent woofer that Henry designed.  The OLA and the NLA use exactly the same voice coil, a bifilar 4 layer coil of high temperature wire on a phosphor bronze former, the same cone, dust cap, and spider.  The tweeter voice coil did change, and so did the crossover.  I re-voiced the speaker to provide flatter on axis and flatter power response.  My only regret is the 3 position switch on the back.  It stayed because we wanted to be free from the possible perception that we were cheapening the speaker in any way.  The speaker is flattest and in my opinion sounds the best with the switch in NORMAL,  and that is how the Advent/1 is voiced.   In the INCREASE position the woofer inductor is bypassed and the very top end of the tweeter is lifted so that the speaker sounds a little weightier, perhaps a better sound for rock music?  The DECREASE position slightly lowers the tweeter level.        April 30, 2021


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Andy, you certainly need no introduction to this audience—your name is well known. A big welcome! Happy to see you here.


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  • 8 months later...
On 4/30/2021 at 3:47 PM, Andy K said:

The moving parts of woofer remained the same as in the OLA.  The surround is inverted so that it projects forward.  Otherwise all the moving parts are identical to the Original Advent woofer that Henry designed. 

For Andy Kotsatos

This background info is so great to hear.  Thank you for jumping in to explain how these wonderful models came to fruition

So can we talk about the surrounds for a bit...  Most of the controversy I have seen is with how the inside edge of the surround is mounted to the cone edge.

On the OLA Henery used a "Reverse Roll" (or with the bulged portion of the surround ring facing inward and away from the listener) with the surround mounted under the Masonite board and the inside edge secured on top(?) of the cone lip. 

 I have seen some OLA inner edges also mounted under the cone lip rather than on top.


On the NLA and Advent/1 the surrounds are mounted to the frame with a "Forward Roll" (or the bulged portion of the surround ring facing outward toward the listener... which is the most common surround configuration we see today).

The contriversy is with the surround inner lip being secured under the cone edge or on top of the cone edge.

1. Which configuration is most is most correct for the different speakers?

2. ...and what are the destructive and constructive differences that occurs from one configuration to the other?

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  • 11 months later...

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