Thanks, Greg

Greg B wrote:

Cap and L-pad resistor quality is critical even in the cheaper models.

I do not use any L-pad resistors with tweeters. If you need to reduce the tweeter output I drop the caps and move the tweeter up at the transition slope. Do not forget that the EV tweeters are dead over 16kHz and all that I need form then is juts to add ½ octave at the top.

Greg B wrote:

The main problem with ribbons is that they need a steep crossover, which is inherently problematic. The other problem is that they seem to have more non linear distortion than good conventional types. Multitone burst tests show this. It is audible as a sort of shimmery silver sound - especially at high SPL, but for low efficiency systems they work OK. Details and image are good to excellent, but integration is a bitch. Best integration I got was with a simple quasi second order series type, which seemed to lock the drivers together. I was shooting for something that started shallow but increased cutoff below the crossover point, sort of like what was just mentioned.

You nailed down the ribbons perfectly. The only thing that I would add that when ribbons sound I feel that that ribbons have diarrhea nd afraid to make any fast movements. Although I still would like to hear those new HE ribbon drivers.

BTW, if you would like to be really entertained then get this :-)

http://www.angelsoundaudio.co.uk/html/golden_sounds.html#UtraTweeter

Rgs,
Romy

Romy the Cat wrote:

Now my midrange channel need no upper range diffusion and now I feel that the result I’m getting from T350 is too soft and too transiently slow for S2. So, I kind of very mildly begin to look out there and to try top fugue out what tweeter I might try. …

I decided to re-appoint again the T350 as a “Phenomenal Driver” ....as for the last 3-4 months while I doubt it the T350's price on Ebay went down. Now the justness is reinstates and the dues are paid.

Hate me... :-)
Romy the Cat

Listening my Macondo with new “Fundamental channel” I noted that my tweeter is not as effective as it use to be. The effect of “not-effectiveness” is very minor but at some recordings it is notable. My T350 still sorts the Vitavox S2’s top but it also begin to pick a tiny bit off fussiness. I presume that it comes from reflections. The EV T50 notoriously want to sit aside very far from everything, including any baffles. Also it wide radiation pattern does not really comply with it’s current location. I will do further experiments, trying to put my T350 horizontally and some other action that “might” be successful (as I do not know the real reasons why the fussiness came to the picture) but I also ask myself if any other tweeter might be utilized in new Macondo.

T350 is wonderfully soft but it 120x60 degree radiation is very completed in context of my current setup.  My initial idea was to use the beautiful copper tweeter from Celestion  (I LOVE that tweeter) but it needs 100+ amplification and no any amplification but very good amplification. It would be too ridicules to have 100W PP SS to drive a tweeter.

Looking (again!!!) at the army of available tweeter with narrowing deposition I discover a new opportunity. Fostex has their T-line compression tweeters, they are aluminum in alnico: T-90A, T-500A, T925A. I had them. They do well with slow and sleepy Altec’s MF (although they even with Altecs a bit too hard to me) but with Vitavox they very brutal. So, how big my surprise was when I discover that Fostex did acknowledge the problem and introduced a new version of thier T-tweeters: T90A-EX and T500AmkII. Those new drivers are the same old drives but with bigger magnets and the diaphragms made not from aluminum anymore but with magnesium.

http://www.goodsoundclub.com/pdf/Fostex_magnesium_foil.pdf

Wow, this "might" be very interesting and practically in context of the Fostex public revelation: “ Pure magnesium diaphragm having superior internal loss, having less unpleasant overtones as heard in other types of metal domes.” Those “unpleasant overtones” was exactly what bothered me in the old Foxtex tweeters, but again, that revelation very much might be a marketing BS and the new drivers might have own “magnesium problems” in sound. I would not speculate at this point as I never heard them the new Fostex tweeters and I fine them as a good candidate.

Did anyone herd them? Did anyone come across any new interesting tweeters some my last tweeters frustrations?

Rgs,
Romy the Cat

It is incredible how stupid sometimes our audio steps are.  A few days ago I was complaining that sound of my T350 tweeter suddenly started to bother me but it was no the problem with the tweeter but rather the problem with my own moronity.

A few months ago I implemented a transaction slope attenuator. It was basically a pile of capacitors sitting in a good quality rotary switch. That allowed me very precisely to dial-in the attenuation of my tweeter. I tuned in my tweeter (it was a step #6 on the rotary switch) and then sine I dissemble my entire tweeter assembly I time-realigned the tweeter.  I was so pleased with the result that I made a post: “Something that a loudspeaker must have.” in my “Audio For Dummies ™” section:

http://www.goodsoundclub.com/TreeItem.aspx?PostID=1487#1487

Since then I have been using the depicted configuration, playing the tweeter all time in the in step #6 and turning it down when electricity is bad.

Well…

although I do not argue with the concussions of that post and do find that an ability to precisely set tweeters amplitude is very important and powerful tool but when I look at THE WAY HOW I did it is really question who is the Dummy!!! I juts realized that THE WAY in which I did it was so much bogus that it is scare. Running the tweeter across the transition slope I unavoidably introduce in each new “click” a new phase offset. It means the correct position of the tweeter relative to MF driver (or angleing of the tweeter) would be different at the different “clicks”.  I spent a few hours confirming that my tweeter was misaligned but I failed to acknowledge that my attenuator was not in the #6 step. This perfectly explains the “mud” and “fussiness” that I experienced. At this point the attenuator was in position #6 and after I moved the teeter a few mm forward then the problem is gone and the tweeter sounded as perfect as before. How much was my surprise when later on during the same evening I moved the attenuator to the default step #6 and begin to hear the same “fussy dirt”.  Of coursed I immediately re-measured the time aliment and off course I was deep in cancellation mode…. What else I was expected ands what the hell I was thinking!!!

I think I have too much time on my hands or use my time in highly stupid fashion but I decided to do today the experiment about witch I was thinking for a while. The experiment was “methodology clean” and lead me to quite interesting discoveries. Since you follow my blog and have as much time on your hands I think it is very much worth to share my observations with public. Also, leaving all foolishness aside, if the subject of this blog and your interests is hard pushing an envelop of advanced audio methods and evolved music reproduction techniques then read on.

I hate tweeters and I hate HOW Hi-Fi reproduce high frequency. There was literary a hand full moments within my audio experiences when I heard produced HF that I liked.

1) A few years ago I heard Grand Utopia (old one, not today’s Be crappy version) driven by some huge German-made PP tube amp. The sound was typical Grand Utopians… with obnoxious laser-like HF. However when I got myself in the very precise distance from the speaker then it was it. Grand Utopia is freaky speaker and knowing how to deal with it I was literally moving inch by inch from 25-20 feet and somewhere when I hit the correct distance then… the tweeter suddenly despair and the HF where execrably how they should be: not auditable and non-existing but hypnotizably non-existing

2) Last year I was listening Wilson Alexandria with Spectral 360 SS PP. I would not comment on the general Sound but HF were incorrect. However, when I was walking out of the room, somewhere near the door it suddenly hit me. In this, many feet away from listing position spot the Alexandria’s HF suddenly collapsed and the effect of the phenomenal HF calmness come to the existence.

3) A few ears ago in a used LF shop there was some very crappy no-name 30 years old dirty bookshelf speaker that was sitting on the top shelf of the store. The speaker was driven by a consumer receiver. The HF were so spectacular (from any place of the store) that it was not even funny. I asked a clerk to play an opera peace that I picked from the shelf and it was literally like nothing else.

4) In June-July 2000, in my own listening room, my speaker (I do not remember which tweeters I used at that time as I changed them monthly) were driven by Lamms ML2 and during the typical movement experiments my speakers hit the  DPoLS. During those few weeks that HF were absolutely incomparable with anything I ever hear in audio. It is absolutely imposable to convey to anybody who is not familiar with the effect.

5) The Celestion SL-600 with copper tweeters and driven by Lamm M1.1 amplifiers. The Celestion copper tweeters are class of their own and there is nothing like they if the amplification is correct. I know, Lamm quite suffers from quite harsh and quite deserved criticism on my site but let pay dues when it is needed: what Lamm M1.1 does compare to other amps when it drives Celestion SL-600 is nothing less then deserving heights respect.

It was it. Any other listening of a playback I ever did annoyed me with HF tremendously. Still, there is a tweeter that always annoyed me lees then any other: it was Electro-Voice T350. It’s phenolic diaphragm sound VERY different from ANY other tweeter I heard. I use this tweeter for 4-5 years and I always suspected that I do not use it properly. I do not let T350 “to sound” but rather inject T350 at the strategic minus 8dB at ~13kHz -15kHz to cure some issues of my midrange Vitavox S2 driver. It did the necessary touch and it was acceptable, at least not too compliable (when electivity is right). However, today I took a single Celestion copper tweeters, placed it atop of Macondo, connected it via Dominus to Lamm M1.1, EQed the volumes and listen the Macondo powered by the Celestion’s copper. What can I say? It gave me sense of new direction. Nope. The Celestion’s copper was not better, in fact it was harder then T350 but …

You see the Electro-Voice T350 is a MF driver. I meant to be used from 3500Kz and it has very flat and very fat MF. It is not good quality of MF but it is there. The first order was not juts able to kill and made me use the “injection method”. I set the T350 with sharper filter and it did quite deferent result. Somewhere at 2rd -3rd order the T350 enters the performing domain of Celestion’s copper but it has very soft stress and very “yellow” HF tone. Mixing with Vitavox S2 it has different result then it use to be but still it has very elegant, very sophisticated and very-very-very-very none-twittery sound.  I do not know in witch setting I end up but the facts remain the very same: there was no other known to me driver that has comparable to T350 ability for sound reproduction. The Celestion’s copper might be very much close but with 82dB sensitively and heavy impedance EQing it might be a problem. You see, to drive the Celestion’s copper you need a >100W PP but the push-pull have inherent issues at HF (die to the transition line asymmetry of push and pull, not to mention if they use feedback).

So, Electro-Voice T350 is potential “the only correct none-metallic HF”, 110dB sensitively and 120 degree deception. Thanks to my public blabbering the prices of the used T350 jumped from $300 to $1000. Good for you. I think it is still much cheaper then many other tweeter and much more interesting sounding. Dose it has anything to do with advanced audio methods and evolved music reproduction techniques?

Fostex T 500A MK 2 Horn Super Tweeter
Article By Bill Gaw at www.enjoythemusic.com

As most of you know by now, I'm a horny type of guy. While my wife may dispute this, my audio system (actually my second partner) would have to agree as all seven speakers are of that persuasion. While the subs, woofers and mid range horns and drivers have been acceptable and stable, using Electrovoice 12 and 15 L drivers for the woofer horns, and TAD 2002 and 4002 drivers for the mid Edgar Tractrix horns, the tweeters have been a problem, for two reasons.

First, to get the best possible sound from these expensive drivers one needs to match the woofers to the mids and the mids to the tweeters in as many specifications as possible to minimize parts needed to run them. Especially with horns and single-ended or low wattage amps, passive crossovers and parts significantly detract from their sound, especially higher order crossovers. Thus, for the main speakers I use VacuumState RTP-5 preamps that were built with 24dB active crossovers as part of the preamp's regular circuitry and Behringer 24dB active crossovers as the preamps for the other speakers. Thus theoretically, no parts are in the circuit between the preamps and amp other than what would have to be there anyway. Only the tweeters have 1 capacitor on them for a 6dB crossover to the mid-horn.

Second, most horn tweeters tend to have frequency ranges that tail off just above 20kHz, such as the Fostex T-500 which this unit replaces, or they extend into the upper 30's but with a somewhat ragged response curve that adds some tizziness in the hearable high end such as the T 900. The lower end of their frequency range may go as low as 3kHz to match up well with the mid range drivers, but the drop-off has to be steep as they begin to have frequency anomalies not too far below that.

If one is using a single amplifier for both the mid and tweeter, one has to match the various driver's efficiencies as close as possible so one doesn't need a volume control in between to muck up their sound. Also, their impedances should be matched. Preferably both should be 16 Ohms, or if one is 16 and the other 8 Ohms impedance then have different efficiencies to match them up. Over the past several years I've gone through several different horn tweeters, and had settled on Fostex T-900A's as the best at about $380 each, but they didn't match up perfectly with the mid-horns, having a lower efficiency requiring the mid horn to be padded down. Also, while they were flat out to 38kHz they had a peak at 5kHz to 8kHz, which is right at the crossover point with the TAD drivers that had to be compensated for.

About three months ago, Fostex came out with the T 500A Mk II driver that seemed to fit perfectly in specs with the TAD driver. While they are 8-Ohm impedance compared to the TAD's 16 ohms, they are slightly less efficient, thus should be a close to perfect match. Its frequency response is flatter than the T-900A, reaching out to 30kHz with useable response out to 50kHz. I know what you're going to say; "Only your dog can hear out to that range." That may be true, especially with my 60 year old ears, but with SACD and DVD-A and even Dolby and DTS digital with 88 to 96 kHz sampling frequency, that information is there and can intermodulate with lower frequencies allowing us to hear its effects on the lower overtones. I think it's that intermodulation that gives, for instance, the shimmer and sheen of violins that is missing in CD.

Anyway, on an online discussion board I came across John Kalinowski, another horny guy who was purchasing several of these tweeters for himself. He graciously offered to get me two at a group rate and also suggested using Mundorf silver-gold caps and the Fostex R100TX transformers for any necessary padding. So the extra pair of T-900's was removed to my rear two speakers with the T-500's placed on the main left and right ones. Using the WinAudio MLS program from Dr. Jordan design ( more to follow possibly next month) the tweeters were found to match almost perfectly with the TAD drivers using just a 2.2 mic. Mundorf cap without the transformer. Thus the transformers were transferred to the side and center speakers and the rheostats previously used on the main speakers were transferred to the rear horns to pad down the tweeters, and with the MLS program, all speakers were matched as well as possible.

As this is not a full review of the product I won't use any fancy high-end gobblydegook to describe my findings. First, listening only to the two main speakers, the difference was subtle but important. Gone was peakiness in the mid-high frequency range. With DVD-Audio and SACD recordings, there was a beautiful sheen to the violins not heard previously on my system and only on those systems heard in the past that used the newer super-tweeters with response extending out beyond 50kHz. You have to hear one of these speakers to understand what I'm talking about. I'm sure my ears cannot pick out sound in that range, but there is a distinct difference.

Romy.
Have been reading various threads to glean information on tweeter options.
I read with enthusiasm your experiences with the RAAL teardrop tweeter until I saw the price, then had to change my plans.

Your brief comments on the T90A ( affordable in the near-term ) were interesting as they would be assisting a GPA 288-H driver on 425 Hz horn ( Azura ) . Do you think with care, in the context of this driver the T90A could add anything useful to the HF ?
Where do you think the problems of eg. the T90A are located - upper MF or HF above 10kHz ?

Thanks for any info you can offer
Mark

Mark,

It is hard to say. I owned T90A sometimes in 2001-2002. At that time I was going through the drivers like crazy and T90A was just one of them. Looking from now I do not think that I gave to many drivers a chance as I did not “work” them trying to get best out of them. I do not remember that T90A gave me any problems, in fact I had the most expensive Fostex tweeter (T5000 or 7000) they had available at that time but I preferred T90A (it was the least expensive Fostex tweeter then).

You see, all those conversations about what I liked or do not likes make scene only in context of the MF drivers that I used at that time. A tweeter is not a self-contained element. A tweeter is a complimentary component for MF channel and they must work together. In the very beginning of 2002 I switched from many other MF drivers that I used before to Vitavox S2, and my first year with S2 driver I was “fighting” with it, learning how to make it to sound right. The Fostex T90A came to me right before or in the middle of the “S2 fight”, so I might be clueless what I was getting then.  In addition I do not know the GPA drivers. I experimented with Altec’s 288 and 290 but never had the GPA drivers. They shell be similar but you never know. JBL and Tannoy nowadays and 40 years back are kind of “similar” drivers, although they are very much not be the same…

The RAAL TearDrop tweeter was an interesting push up. It was an opportunely for me to see what 109dB sensitive ribbon is all about. In addition I was looking for a very narrow vertical window to let the tweeter in its time-aligned position to shoot between the horns. From what I see ribbons have advantages over compression driver in HF region. With each single hertz the frequency goes down the ribbons loosing their advantages and compression drivers take over…

Anyhow, I do not think that I might be a good source for you to learn about T90A. In past Madidound was offering to send drivers to try, they might still do it. If so, then grting from them the T90A for a week or two shell answer all your questions. Make sure that the T90A is scrupulously time-aligned and it’s axis is meticulously paralleled to the 288’s axis. 90% of the problems with tweeters out there are about the people do not align them properly….

mats wrote:

I have found the T90A to be reasonably in-offensive with JBL 2435 Neo/Be compression drivers. I use them with relatively small caps, currently 0,3uF. The effect is a welcoming of a higher frequency palette that to my ears does not seem incongruous with the JBL's. I notice in the article above that Bill Gaw used his 500's with a 2,2uF cap. That is a very different implementation.