Tannoy supertweeter query - slight return

Having given up on my quest to find out what tweeter Tannoy use in their supertweeters, but having had confirmation from Tannoy the the crossovers I bought do indeed come from their ST50's, I'm now looking at buying some suitable tweeters to use with them.

Anyone got any suggestions? The Tannoy supertweeters extend to 54Khz, but I've looked at a variety of tweeters most of which don't go that high - not sure what the requirement really is, but I'm assuming that for the crossovers to work well with whatever tweeters I use then the tweeters should have at least similar performance to the ones Tannoy use....? ?

My budget is up to about £65 for the pair, and I have found the following options:

Morel MTD-20 (v. cheap at £30 the pair, but only go to 25Khz, soft dome)
HiVi Rti.3 (£63 per pair, but only go to 30Khz, ribbon tweeter )
Fostex FT17H (£66 per pair but v high sensitivity at 98.5, but go to 50Khz, horn tweeter)
Vifa DX25TG-05-04 (£48 per pair, go to 40Khz, soft dome)
Vifa XT19TD-00-04 (£64 per pair, go to 30Khz, ring radiator).

i'm tempted to go with the Vifa DX25 as it's competetively priced, extends quite high, and is average sensitivity.

Any comments - comparative qualities of soft dome vs horn vs ribbon vs ring radiator?

 

Murata?

 

Hmmm, the ESTD01 tweeters would be great, but they're expensive: $299 each from the US, 12-14 weeks waiting time.

I was really thinking £30 each kind of thing...the crossovers only cost me a tenner off fleabay! I realise I'll probably end up with a slightly flawed product, but at least I'll have an idea of what difference, if any, a supertweeter can make to my system.

 

Hi

I would try to investigate the graph response of your existing tweeter.

I would want to know not just a simple cut-off point of the tweeter I was using, but to see at which point it begins to roll off and how steeply the curve decreases.

I am convinced that the merit of a supertweeter is that it extends the tweeter you are using from the point at which it begins to cut off (usually within human hearing) to the limit of human hearing.

As such, the performance of a supertweeters highest point ... 30khz, 50khz etc is a moot point... bats need apply here.

I would also want to see (graphically) the response curve of the supertweeter to see if it could adequately fill in above my existing tweeter.

Finally, I would want to be able to adjust the crossover and level of the supertweeter to match the loudspeaker.

 

According to http://www.hilberink.nl/codehans/tannoy4.htm, my Monitor Golds extend to 20Khz, but it looks like they begin to roll off at quite rapidly at about 17Khz or so. So, in theory, as far as I can tell they don't need help in the audible range. The Fostex tweeter I'm currently considering (FT17H) has a fairly level response between 10Khz and 35-40 Khz. The ST50 crossovers I have benefit from two selectors that allow the following position to be selected, to match the tweeter to the existing speakers:

Frequency 14, 16 or 18kHz adjustable
Type 3rd order high pass
Level adjustment 85dB, 89dB, 93dB adjustable

The problem is that I don't know the tech specs of the tweeter that the ST50 crossover was designed to operate with, so am not sure I'll get results that are close-ish to the ST50 with a different tweeter...... I know bugger all about crossovers or in fact any electronics, which doesn't help, ha ha.


I have to admit that I don't think my speakers suffer from a lack of treble or anything, but am intrigued by the claims of Tannoy/Townsend/Murata etc. that their supertweeters add something to lower frequencies as well, by mechanisms that I certainly don't understand. I've read many reviews of various products that suggest that these supertweeters, operating predominantly at frequencies above normal hearing, can produce noticeable improvements in soundstage etc. I'm not saying that I necessarily believe all I've read, but I'm curious enough to have a listen!

 

My kef 203 refs, latest versions, have super tweeters, and putting a sock over them definately reduces the air and sense of space in the image.

 

You would do because they cross at 15Khz using shallow slopes. In other words the tweeter in the Uni-Q array has had its balls cut off.

 

hmmm, perhaps they chose to do that because of issues with reflections at the throat? Many coaxials seem to have response dips and peaks above about 10KHz and that would be a nice way to bypass those.

 

Perhaps but there's still problems there. I've measured my Ref 201's and there's lobing between the supertweeter and uni-q tweeter due to the relative distance vs. wavelength issue between the two. These aren't too bad due to the shallow slopes but still definitely audible off axis.

I haven't disabled the XO to see just which is the worse of the two issues.

The Uni-Q tweeter sounds fairly rough to me when you get up close but the averaging between the supertweeter at distance seems to greatly mellow it out which could suggest that even with the steps you mentioned there are still problems.

 

Toilette - does the fostex unit you are considering allow you to adjust crossover point and output in the same manner as the Tannoy?

If not, are you happy that you can get these features set up for you (either by yourself or someone else)?

Would the price of this additional work take you over the price of the Tannoys?

 

Sorry, I don't think I made things clear previously; I have a pair of these Tannoy crossovers (from a pair of ST50's) that allow adjustment of the level and frequency at which the supetweeters kick in, and I was simply hoping to connect a pair of appropriate tweeters to these crossovers and achieve similar results to the 'complete' Tannoy ST50's.

However, some recent helpful info has led me to believe that drop in replacements for the Tannoy tweeters may not be readily available at my price point, and even if I do get some then further mods would likely be necessary to get them to work well with the ST50 crossovers. Ho hum.

 

ah well.. seems quite likely..

these things do turn up used, so maybe that's your best bet...still think you would struggle for £65.

Spend £80 and get a copy of CARA, that's my advice..

 

I use a pair of ST50s with my Lancasters. They do work, but the difference isn't night and day. I wouldn't worry about it too much. I bought mine ex-dem for about £300, at which price they're a nice improvement, but not tremendous VFM. IME the improvements they bring are not entirely to do with HF extension, but I have no idea why that may be. DC drivers do have HF roll-off around 14kHz, but then so do most human beings once they get close to middle age...

-- Ian (still has some hearing up to 17kHz, amazingly enough)