STOP STOP BRAD STOPPPP!
What am I stopping? ???
Maybe talk you out of moving that tweeter down on the baffle by boring a big fat hole in that fine Ziggy veneer?
What is the tweeter crossed at?

First off, this experiment is nothing like the MK-II. Efficiency of the FE206E is much higher than that wool driver as you know. The cabinet tuning is completely different - the MK-II uses the original MK-I tuning and passive radiators while mine has the "alternate tuning" of the MK-I with the new passive radiators. Also, the Aurum Cantus G2Si tweeter is about 4db more efficient than the HiVi tweeter better matching the FE206E output *and* the G2Si stays flatter out to 40k, real super-tweeter territory, though the merits of this is debatable.

Now, this is all fuzzy (perfect world) logic but... even though the crossover is high - somewhere around 25K, it is a 1st order. So at 25K we are 3db down (~93db/1w) from the 96db/1w spec, and 9db down at 12.5K (~87db) and somewhere around 6db down (~90db /1w) at around 19K.  Since this is additive to the FE206E's treble output wich is efficient even out to the 15-18K range, it's not difficult to see how this crossover setting is creating the brightness I was hearing.

I would not want to an inductor or any other components in the signal path to the FE206E because of the risk of messing up what it does and does well.  Maybe it would sound better? I'll leave that up to someone else to experiment with.  I'm looking for modifications that are purely additive without altering what is already there - which is very good.

Btw, I had some 0.47uf caps sitting around (two Auricaps and two AudioCap Theta's) and tried them out, replacing the 1.0uf Crescendo's with a pair of them in parallel - one of each brand.  You wouldn't think that a change from 1.0uf to 0.94uf would make much of a difference. But the result sounded smoother and less bright.  I much preferred it this way.

I listened to Diana Krall on CD and Andrea Bocelli on SACD. In particular the orchestral passages on the Bocelli disk sounded very very nice.  HDT indeed. This is a SHDT... Super High Definition Tower

More listening and/or experimenting to come.

hmm, this made me think about something.  When you turn on a tv it makes a high frequency wining sound; what frequency is this sound?  -Matt

Hi Brad,
Going by memory, I don't believe the Aurum is a dipole ribbon (I'm too lazy to look up the spec sheet). If it's not, why don't you try mounting it on the rear of the cabinet firing towards the back wall. This should cut down on the brightness some w/o losing the air and sparkle this driver is capable of producing. Let us know.

Bill

Brad,

You really motivated me to try some tweaks myself.



The coconut tweak. This really fattened up the sound.  

Corey

Okay guys, I saved my best tweak for last. The Archery Research AR 31 tweak. This tweak is just plain deadly. I have kept this one to myself for quite some time but felt guilty. You saw it here first!  ;)

Corey

Brad the man just loves his HDT´s cant blame him
I´m moved between fascinated and horror,following youre tweeks (kind-off like C.S.I) Its like watching the autopsy of a loved one(Im a newlywed HDT owner) but at the same time looking for the key to the safe-deposit box in the corps. I´m just glad its your HDT´s and not mine.......Youre A braver man than I
Keep us posted

and take care, H.

[quote author=Hrappur  link=1126166044/0#13 date=1126398104] I´m just glad its your HDT´s and not mine.......Youre A braver man than I
[/quote]

Why am a brave? All the things I've tried (so far) are reversible.

One conclusion I've already come to regarding the addition of the ribbon tweeters, they make bowed string instruments sound way more real/palpable. Maybe it's the added upper harmonics? dunno? But violins and especially Cello's sound way better. Plucked instruments also are crisper, but that I was expecting.  

The clarity I hear on some songs is literally startling at times.  ;D

I've done some other tweaks to my TABOO and CSP that are of course contributing, but the tweeter is undoubtedly a large part of it.

Brad,

     Okay now it is time to get serious. This is a serious tweak to the HDT's. True Triode.




Take care,

Corey

Looks a bit like mono Corey

[quote author=brad  link=1126166044/15#22 date=1127437343] I just sent my Sony DVP-NS999ES SACD player into Modwright to have an interesting mod done to it.  Various simple mods in addition to completely bypassing the output stage, going direct from the DAC to outputs, and thereby bypassing a number of cheapie components in the signal path.  The high-gain of the CSP preamp allows me to do this.  Steve says he's done this type of thing before with good results.

Stay tuned fellow Dec-heads  :D [/quote]

I did the same with a toshiba 4960.  
(A handful of black gates and going direct from the DAC to new outputs).  
Works great (for not being vinyl...)
Robert  :)  

Brad,

I think it's a neurosis
I am also afflicted to the point I have to have my super/ultra tweet. Mine is crossed lower (13-14K) to help my older Fostex FE166.
You will probably agree that the type and quality of the cap makes an enormous difference in what you hear. I am still looking for the best sound from the cap in my setup. You mentioned Mundorf silver/oil (not foil?) and I'm planning to get several different types (and get serious soon) to try. Is that an oil filled cap you're talking about?

Robert,

OB, along with 2 - 15" OB helpers and a paper/mylar tweet, it's all working pretty well together. I actually cut away the tweet's mounting flange to decrease CTC and got them about 1/2" closer. I'm not sure how much that helped, but I feel better. Any recommendations for a see-through (hear-through?) XO cap?

Hey Brian, Madisound sells Mundorf

Thanks, Brad

That even gives me a place to start.  :)

Franksmith,

This is what Steve Deckert wrote on the subject in this paper:

https://www.decware.com/paper18.htm

Take care,

Corey

Small follow up.

I've tried the supravox 285 in bass renforcment. Even if they are very good, they simply can't follow the hdt and remove the impact of the hdt bass. I can't understand how a regular subwoofer can match with theses whitout altering the sound of the hdt. Just try "take five" from Dave Brubeck with and without the subwoofer it's incredible how the sound of the drum change with subwoofers. Probably a question of priorities (extention vs quality)

Also I realized that the hdt where working a little bit too hard to fill my big room.

What I've done is separate my room in two and use them only in half the space I was using with my acoustat X.

The new "room" is now around 11' by 15'.

The change is impressive, I use almost half the power I was using before at the same sound level. The bass is now way more present and the mid bass as more body, almost as my stats. They are still alive but I will need to do some acoustic work with resonnances when I raise the volume.