Another newbie question: if a 1" dome tweeter's dispersion is a problem as far as diffraction effects, why not use something larger? KEF did this by equipping their first 105 series with a 2" dome. Plus I assume a larger dome can more gracefully handle a low xover point.
There's another model pictured next to it also using a cone tweeter, but this time equipped with one of those acoustic "lenses". No idea if those lenses are still a good solution or not (JBL used them a lot).
Check out page 24 for a loudspeaker, the T-200, with such a tweeter (though I'm not saying this particular version sounded good, just that it matched the description you wrote).
There's another model pictured next to it also using a cone tweeter, but this time equipped with one of those acoustic "lenses". No idea if those lenses are still a good solution or not (JBL used them a lot).
Last edited:
Using a larger dome is like using a full range driver. They have reduced power response at the top and they beam a little. The benefits, in my opinion are that they have a relaxed top end (when properly balanced) which is easy to listen to, and something I liked before I knew what HRTF was. Their top end also makes them a good choice in my opinion for background music as they can be set up to not grab your attention (and sound similar as you move around due to the single source). Of course for serious listening you need to stay put - due to the beaming.
Thanks Allen.
BTW I wanted to quickly mention a non-DIY tweeter (and long out of production!) that uses a dome, but not exactly a dome, and see if anyone had any thoughts about this non-traditional design: Roy Allison's high frequency driver.
BTW I wanted to quickly mention a non-DIY tweeter (and long out of production!) that uses a dome, but not exactly a dome, and see if anyone had any thoughts about this non-traditional design: Roy Allison's high frequency driver.
Last edited:
The problem with just making a dome twice the size (well one of the problems) is that you only make it more directional at the top end of its range, when it really needs to be made more direction at the bottom end. At the bottom end where you're trying to cross it over with a midrange driver the directivity is still controlled only by the baffle.
A flush mounted dome on a flat baffle will have a full 180 degree radiation angle (albeit perturbed by diffraction effects unless the baffle edges have large radius curves) from its low end up to some frequency where the directivity of the dome itself starts taking over - for a 1" dome this is about 8-10Khz. Above this frequency the radiation will progressively narrow with further increases in frequency.
Doubling the diameter of the dome would at most halve the frequency where it just starts to become more directional than 180 degrees, so the 2" dome would just begin narrowing its pattern at around 4-5Khz. If you were crossing it over at 3Khz or below there will be almost no change in directivity there, (still controlled by the baffle) thus no better directivity match to the midrange driver, and still significant diffraction effects as high as 5Khz or so.
What's more, you've now made it much more directional at the top end, and because the bottom end directivity is still constrained by the baffle you now have a much greater total shift in directivity/power response from the bottom end to the top end than you would for the 1" dome, which may or may not be desirable.
On the other hand, take your same 1" dome and place it in a well designed wave-guide, and the story is very different. Now the wave-guide controls the low end directivity of the driver, constraining it to a set angle, lets say 90 degrees. As long as the wave guide is large enough it can maintain this angle to well below the crossover frequency for the tweeter, helping to achieve a good match to the midrange driver, as well as minimizing diffraction effects.
As frequency goes up the directivity stays much the same until we reach the point where the directivity of the dome itself starts to narrow (8-10Khz for the 1") where it will again narrow progressively.
Directivity is uniform over all but the top octave, and total shift in directivity from the bottom end to the top end is much less than a naked dome of either size. Power handling and maximum SPL at the bottom end of its range (where domes struggle) is greatly improved.
I don't think there's much real science behind those old acoustic "lenses", and that they were a fad of the times.
I've heard speakers with them and wasn't impressed. They're just trying to take the output of a driver that is beaming badly at high frequencies and attempting to deflect it to "increase" the dispersion. Trouble is all the little reflecting surfaces cause a mishmash of reflection and diffraction which really messes up the frequency response. Off axis response might be increased slightly at the expense of a really awful looking frequency response and a peculiar lumpy polar pattern.
Better to start with a driver with the desired dispersion and design from there rather than add a band aid.
Last edited:
Good question. If you're asking have I measured the electrical performance of the transformer in isolation, (saturation/distortion/frequency response etc) the answer is no. I see (and hear) nothing in the acoustic measurements that would suggest the transformer has any significant negative effects though.
The transformer is as large as the entire magnet structure, (at least on the G2) and as it is always driven through a high pass filter it's not subject to much power, nor low frequencies unlike a broadband transformer in say a valve amp.
Because of this they're able to use a low number of turns on the windings to minimize chances of saturation as well as ohmic power losses. (DC input resistance on the primary is below 0.1 ohms, the secondary is probably a "1 turn" rod or strip, and the transformer cut-off frequency is about 200Hz)
In theory it could add a small amount of distortion at high power levels, (I assume its cored) but its probably orders of magnitude lower than any distortion generated by the diaphragm itself.
Since the transformer is integrated any slight errors in frequency response it might introduce simply become part of the transfer function of the driver as a whole from a crossover designers perspective.
You're right that the quality of the transformer needs to be taken into consideration on a ribbon, but in this instance I think they've done a good job of engineering it.
The Allison tweeter has the widest dispersion of any tweeter I know of, wider even than the AR 3/4" dome. This is due to the ingenious method of driving the cone partway in from its edge and providing a flexible section. This effectively causes the outer perimeter to radiate some sound nearly 90 degrees to the axis of the voice coil. Yet even for Allison this was not wide enough and he incorporated two of them on angled panels increasing lateral dispersion even further. This was a kind of follow on development beyond AR LST.
The design is of course diametrically opposite of what those who favor tweeters that beam their sound in a relatively narrow cone that shrinks as frequency increases advocate. That type of tweeter is typical of most modern designs. The reason is that when carefully positioned and you listen at just the right spot, "imaging" is said to be improved. It also reduces high frequency interactions with the listening room. IMO it is also responsible at least in part for the shrillness many speakers exhibit that is not characteristic of acoustic musical instruments.
To go simple again (non technical talk) : Quad Electroacoustical with their combination of valve amps and electrostatic loudspeakers promoted their audio equipment thusly: 'for the closest approach to the original sound'. No doubt memory fails me these days but I do seem to recall being enthralled in the 50's when I got my first Quad setup ... it was indeed a satisfying rendition / translation of the original sound and yes, to preclude the obvious interjection, I did also go to live concerts regularly and was also familially/socially surrounded by accomplished musicians. I have yet to hear a domestic sound system that translates the recording of a live performance into a reality; some convince better than others but it is still an illusion is it not? If that indeed is the case then the best any musician or music lover can hope for is that the recording engineers did their job well (it seems/sounds to me at least that most certainly didn't) and that designers of audio equipment from source to speaker (and architects to room) also did their respective jobs well. Regrettably the number of variables lurking within all of these factors are immense and I would propose that any system or technology that lays claim to being 'the best solution' today still remains inherently flawed: arguing that any super horn or perfect waveguide can faithfully induce the psychoacoustic pleasure or actual reality of a live concert is somewhat moot since no audio system can do that save for reproducing certain small ensemble types of recordings where the original sounstage was small. Whether trained musicians or otherwise we all obtain our pleasure from music in our own specific way and whilst there may be general concensus agreements even long-time audiophiles/musicians have differing values and viewpoints. Enough said. To the OP question - cheap tweeters are just that - cheap, and for the most part since big business finances and marketing dictates what 'the mass public' wants or is told that it wants then cheap will always be in the buying equation for the minority. Fortunately there are smaller companies who do cater for the more 'experienced' ear and we can also each construct what is pleasing to our own ears so thank God for entrepreneurial individuals and DIYaudio.
Now, can anyone suggest a reason why I find Focal's inverted domes, be they Tioxid or kevlar, to be so much more satisfying and non-fatiguing to listen to than just about any other make/type/shape of tweeters in a loudspeaker of conventional design. And no I can't afford ESL's or good hybrids nowadays - I may still have okay ears but unfortunately I also have very shrunken and shallow pockets
Now, can anyone suggest a reason why I find Focal's inverted domes, be they Tioxid or kevlar, to be so much more satisfying and non-fatiguing to listen to than just about any other make/type/shape of tweeters in a loudspeaker of conventional design. And no I can't afford ESL's or good hybrids nowadays - I may still have okay ears but unfortunately I also have very shrunken and shallow pockets
Now, can anyone suggest a reason why I find Focal's inverted domes, be they Tioxid or kevlar, to be so much more satisfying and non-fatiguing to listen to than just about any other make/type/shape of tweeters in a loudspeaker of conventional design. And no I can't afford ESL's or good hybrids nowadays - I may still have okay ears but unfortunately I also have very shrunken and shallow pockets
Hi Seebert , what do you think of these focal tweeters ?
Focal TC90 TD5B - RumoH - Caps, coils and speakers
Hi Iduarte. They're not one that I'd go for. I found the TC120 types better and in the 90 types I found the TD5's to be (IMHO) simply trading on the old Focal name for tweeters. Their sound is really only a shadow - and a poor one at that - of the earlier types. It seems that all later types with the notable exception of the ridiculously expensive of the Be 'flower Power' which is very (very) good in the right cabinet but (as said) carries a huge price. IMHO if you are going to use Focal tweeters try to search out the T120 series - T120 Ti02 or the T120 K's (kevlar diaphragm). Others however may disagree and it always in the end depends upon the ears that hear them. Best to you and lovely Portugal, was there many times in the 60's and 70's. Mike.
You have to understand the audience and if you are asking about DIYers then you have to realize that there is an inherent excitement for most in finding "diamonds in the rough". A DIYer generally gets more excited and feels like they have a bigger accomplishment when they use a cheap tweeter and have great results.
DIYers also seldom are the ones with disposable income to spend on $500 or $1500 Tweeters so when a very cheap tweeter works well for them it fits their budget and their requirements.
People will always accept compromises and in the audio world is extremely easy to convince ourselves that product X is great. Its also easy for controlled listening tests to show truely what differences actually exist (or don't exist). Remember the critical range of content is 20Hz to 5KHz.....Midrange and bass are 100times more important then any tweeter. I would even say that > 15KHz is a complete waste of $$$ and discussion time UNLESS all other ranges are perfect first.
FWIW, Im a DIYer that does not like some of the popular cheap tweeters (dome or CD). They sound like crap, its like convincing ourselves that a Ford Focus is a great car (I have a friend that argues it but he has never owned a high end car and its just about getting to work every day with him)
For me High end music speakers require Ribbons and High End HT speakers require Berylium CDs (TAD or upgraded JBLs). Although Electrostat type designs like the ones from ML can sound amazing if we know their limits (do not play them loud). Of course its amazing what some manufacturers use in their speaker designs then sell them for maybe 50x their cost
Last edited:
Thanks Seebert , Portugal is still a great place to visit or live in , except for this economy that drives us all crazy.I tend to prefer metal dome tweeters though they sometimes sound harsh , i´m yet to find a soft dome that sounds right to my taste, that´s why i was asking about the focals.Ribbons are ok but the tend to have some distortion compared to domes.Kind regards Luis
Last edited:
Quality Ribbons have superior distortion measurements from all that I have seen so Im confused on that point
A Dome can not compete at all from everything I have seen.Granted a Ribbon does not play low but if we are comparing any driver we should be using the maximize performance range of that driver.
Quality Ribbons have superior distortion measurements from all that I have seen so Im confused on that point
Granted a Ribbon does not play low but if we are comparing any driver we should be using the maximize performance range of that driver.
You are right , but i cant spend more that 150$ on a tweeter and quality ribbons are expensive.
Yeah, I think its very important to first figure out all requirements. Driver selection/design selection can not happen all requirements are defined. Its nice to have a general discussion like this thread but some designs require expensive tweeters.
Case in point, my latest 2-way horn design is using the larger IWATA-300 horns with a 2" throat. Try pricing out a 2" CD that sounds/measures nicely above 10KHz (yes, for all the experts, I fully understand beaming above 8KHz with 2" CDs). I found two solutions, both are over $500 per tweeter Spent > $3K on tweeters alone to figure it out. Atleast I can sell the unused pair and maybe get back $1.5K
Some solutions do not have a < $150 tweeter option
btw, this same holds true for Ribbons, it seems that we have to spend $300 maybe $500 to get quality ribbon. Of course cheaper ribbons can be used above 3KHz which is okay in a multi-way type design like the Statements. Again, its important to handle that midrange and I think the most money should be spent on 20Hz to 5KHz.
Case in point, my latest 2-way horn design is using the larger IWATA-300 horns with a 2" throat. Try pricing out a 2" CD that sounds/measures nicely above 10KHz (yes, for all the experts, I fully understand beaming above 8KHz with 2" CDs). I found two solutions, both are over $500 per tweeter
Spent > $3K on tweeters alone to figure it out. Atleast I can sell the unused pair and maybe get back $1.5K Some solutions do not have a < $150 tweeter option
btw, this same holds true for Ribbons, it seems that we have to spend $300 maybe $500 to get quality ribbon. Of course cheaper ribbons can be used above 3KHz which is okay in a multi-way type design like the Statements. Again, its important to handle that midrange and I think the most money should be spent on 20Hz to 5KHz.
Last edited:
Now wait a minute. The new Focus is a whole lot better than most cars out there. I say drive one before you knock it. Sorry for the off topic....
When I bought my Raven 2's one of the reasons I put down the big money was the quality of the transformers being used. When I asked around they were arguably the best tweeters out there. I wanted to buy them once and be happy with them for the long haul and not feel the need to change them. Solid logic that has worked so far. It hasn't stopped me from building speakers, but it has made it so I am happy with the main speakers I have and have then played with building other things just for fun.
When I bought my Raven 2's one of the reasons I put down the big money was the quality of the transformers being used. When I asked around they were arguably the best tweeters out there. I wanted to buy them once and be happy with them for the long haul and not feel the need to change them. Solid logic that has worked so far. It hasn't stopped me from building speakers, but it has made it so I am happy with the main speakers I have and have then played with building other things just for fun.
Hi again Luis, good to hear that Portugal is still as beautiful - great country with very friendly people. I've been through one or two ribbon phases when I had the money to play with valve amps which to my ears at least brought out the best in them, but now I'm all transistor and couldn't afford to spend on an amp that worked well with good ribbons. I've never found the metal Focals to be harsh, just detailed, smooth and extended although I've always heard them matched in an all-Focal speaker but I know what you mean about metal domes. I have some in a pair of A3+2's and they can make your ears bleed
Focals do come up on EvilBay (eBay) from time to time - for example the 90TD5's you mentioned : FOCAL TC90TD5 Titanium Tweeters. New Pair. Tioxid Inverted Dome. Shielded | eBay
Cheaper than your store price but not good units IMHO. NO relation to the seller by the way. JMLabs (Focal) are not too helpful in giving information on older units but you might find the K's taken from an older KRK monitor (they do sound good) but the T120Tio2's are getting rare. Just out of curiosity I did try a pair of soft domes from a vintage pair of ADS L520's and they sounded very nice - you may find these pretty cheap and worth a listen.
I know how difficult it can be to get US parts sent to Europe (and some dealers don't ship to Europe) but if you find anything you want let me know and I'll be happy to do a pick up and ship for you at cost. As they say, we gotta stick together in this life
Best regards and wishes, Mike.
(Apologies to the OP - didn't try to hijack the thread)
Focals do come up on EvilBay (eBay) from time to time - for example the 90TD5's you mentioned : FOCAL TC90TD5 Titanium Tweeters. New Pair. Tioxid Inverted Dome. Shielded | eBay
Cheaper than your store price but not good units IMHO. NO relation to the seller by the way. JMLabs (Focal) are not too helpful in giving information on older units but you might find the K's taken from an older KRK monitor (they do sound good) but the T120Tio2's are getting rare. Just out of curiosity I did try a pair of soft domes from a vintage pair of ADS L520's and they sounded very nice - you may find these pretty cheap and worth a listen.
I know how difficult it can be to get US parts sent to Europe (and some dealers don't ship to Europe) but if you find anything you want let me know and I'll be happy to do a pick up and ship for you at cost. As they say, we gotta stick together in this life
Best regards and wishes, Mike.
(Apologies to the OP - didn't try to hijack the thread)
Quality Ribbons have superior distortion measurements from all that I have seen so Im confused on that point
Granted a Ribbon does not play low but if we are comparing any driver we should be using the maximize performance range of that driver.
I think it depends on the frequency they are supposed to cover.
As a regular tweeter Zaph was less than enthusiastic about them but if I remember correctly ribbons measured quite well above around 7kHz but quite bad below.
I do not think its that fair off topic, it goes to the subjectivity of the individual. Its not even close to what exists out there in terms of performance from Audi/BMW/Mercedes. I do rent new ones since I travel monthly but its crap to me, for a rental I try to get something like Malibu choice instead better highway performance. I think its always comes back to experience, any POV has to have extensive experience if its meaningful.
I bet those Raven choices sound amazing!! Im a huge fan of Ribbons for music but Im a waveguide/CD/high dynamics guy when it comes to HT and Im happy I bought TAD CDs.
I think Zaph simply had an agenda. He never even bother with a quality ribbon so I simply would ignore Zaphs opinon/measurements. Anyone that owns high end ribbons simply will disagree with Zaph's subjective conclusions. A person just needs to look at a RAALs measurements to know Zaph picked a bad Ribbon choice to prove a point. You can also use the Statement designs as an indicator to performance. Its one of the top DIY choices out there (atleast in the US).
Last edited:
The thing is, ribbon tweeters will never be "cheap" in the context of this thread, (eg under ~$100) because they require a very powerful but physically small magnet to get sufficient flux density to obtain a useful sensitivity. (It's very hard to get BL product in a ribbon as the gap is so wide and you only have one "turn" of voice coil cutting the lines of force)
In practice this means ferrite and other cheap magnetic materials are unsuitable with the only real option being neodymium. As we know, neodymium was never cheap, and it has recently seen a price hike, so all ribbon tweeters have gone up in price accordingly.
Before the neodymium price hike there were some tolerably priced good ribbons though - I think the G2 were down to around $140US just before the hike, comparable to a high end dome, and around half the price they were when I bought mine in 2004, but I see they're now back up to $219 on parts express.
It looks like both the US and Australia will be restarting mining of neodymium soon, so expect prices of neodymium based drivers to gradually fall over the next couple of years, but I doubt we'll ever see any good sub $100 ribbon tweeters so long as neodymium is required.
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.