adding a tweeter to the Azuras.

[dave slagle]

had a chat with johnny and this is what came out of it.

For a while i have been skeptical of the whole supertweeter thing particularly those that go out to the 60K range (in frequency not price) I trust the reports of an improved sound but the skeptic in me needs a little science to temper my easily swayed placebo laced brain.

SLK has these Townsend supertweeters that roll in at 20K and go up to 100K. The reports of changed sound do not surprise me, but the possibility of another explanation aside from the obvious was still resting in the back of my head. I think it was JJ that brought up the idea that the Townsends are simply in parallel with the Azurs and the GOTO's and they must be providing some kind of load to the rest of the system before them. I looked a bit and found that they provide a 6R load at 20K which falls directly in parallel with the load of the azura and the GOTO. Now we have a controversy that we can sink our teeth into Could the load provided by the supertweeter in parallel be causing the perceived change in the sound and not the extended frequency presentation? Without knowing all the details of the townsend, it is pointless to talk more on the issue, but the concept really got me thinking.

The Plasma tweeters were all the rage at the RMAF and Johhny and i were talking about them. As an alternative he brought up the RAALs that Lynn likes and i mentioned the sequerra T-1's and the various efficiencies quickly became the problem.

Of course i said just multiamp and the efficiency becomes a non-issue but the simplicity of a cap and a tweeter hanging off the azura seems so benign.

This is where the circle closed tonight on the phone with Johnny. If we accept the possibility that the Townsens in SLK's system could be imparting its tone on the system partially by the load it provides to the amp driving the Azuras, it is quite possible that the GOTO is doing the same. Plus the GOTO is rolled in at something like 13K so its "loading" effects have to travel well into the audible band.

At this point it is more of a conceptual "argument" on how to let the Azura play "pure" and simply roll in the extremes.

The bass seems to be taken care of, but the parallel combo of the azura and the "tweeter" seems like it could use some thought.

here is what i came up with. discuss.

[galibier_numero_uno]

Hi Dave,

Happy New Year to all. You (as usual) got it spot on ... that the tweets are likely reflecting a weird load into the amp. I had some Townsends on hand before this year's Audiofest.

Yes, there was an audible change, but overall I wasn't all that happy with the sonic results - neither when using my amps nor with several of Mike Sanders' Quicksilvers (single ended KT-88's as well as 300B's).

Mike suggested a quick and easy experiment. Leave the tweets in circuit and cover them with a towel. If you still hear the "highs", then it's not resulting from what's coming out of the tweeters but rather the load reflected into the amplifiers.

BTW, the Townsends are WAY down in efficiency when compared to even a naked Lowther, let alone anything like a front loaded Lowther or compression driver. IIRC, their peak efficiency comes in at about 30K and it's something like 84dB ... at least according to the spec sheet they distribute with the units. I have no idea why they claim something in the 110dB range for these.

Cheers,
Thom

[Steve Kaufman]

Hi Guyz

There is something to Dave's theory but it is not "spot on." There are possibly some loading effects but the tweeters have a lot to say in their own right. Jonny and I did the Sanders experiment. We compared a couple of tracks with 1. Super tweeters in: 2. Supretweeters out: and 3. Supertweeters in, facing the wall, and covered with a towel. The sound with the tweeters in gave by far the best transients, air, and richness. With the towels over the tweeters the dynamics, air, and richness were the least desirable. Intermediate (closer to the tweets in and covered than tweets in and uncovered) was the sound with the tweets out. With the tweets out there was more richness/smoothness but lacking were the air and great transients.

We would conclude that because of the differences between the tweeter out and tweeter in and covered MAY be related to the loading thing you refer to or perhaps some other interaction. Clearly, in this Azurahorn system, the Townsend Super Tweeter improves the dynamics, air, and richness (juice) over the other two scenarios.

By the way, we haven't done all of our homework. There is an 8 position switch on the back of the Townsend that is used to adjust the sensitivity (gain) from 80 to 110 db (www.townsendaudio.net). At position 4 Townsend shows a graph that depicts the absolute output at 40KHz, where the curve levels out, at 85 db. I use the #8 position (not shown in the graph) which, at 110db, matches the efficiency of my Goto tweeters (110 db) and Azurahorns with Lowther drivers ( not specifically determined but in the ballpark as shown by the spectrum analysis Mike Sanders performed in my listening room. Now you can understand why "they claim something in the 110 db range."

Happy New Year

Steve and Johnny