I'm wondering why the fabric/soft dome tweeter is prevalent with manufacturers. Few seem to make metallic domes and those that do often have a bigger selection of fabric domed tweeters on offer. I have also noticed, in the specs, that fabric dome tweeters appear to have greater power handling capabilities. then there's the coles mylar tweeter... What's going on there?
The break up modes in soft dome tweeters are less severe due to the damping inherent within the dome material and most people find this pleasing to the ear.
Metal domes produce more severe breakup modes resulting in large peaks in the frequency response but some people perceive this as increased detail.
Mylar may be a half-way house?
Of course, the sound of a tweeter depends on other design factors, not least the design of its associated crossover, and there are good examples of all of the above dome types.
Metal domes produce more severe breakup modes resulting in large peaks in the frequency response but some people perceive this as increased detail.
Mylar may be a half-way house?
Of course, the sound of a tweeter depends on other design factors, not least the design of its associated crossover, and there are good examples of all of the above dome types.
Manufacturing complexity plays a role. Metal dome units require more effort to get good performance. Now, metal dome tweeters perform very well and are my preferred choice. There are good examples on both sides of the fence, but good metal domes don't break up at all in the audio band. I am not sure that can be said of soft domes.
While they don't necessarily break up in the audio band, they still show harmonic distortion spikes lower down in the frequency range.
Chris
Metal dome break up occurs (if at occurs at all) at frequencies in excess of 20kHz so that recorded music rarely excites it (CD is steeply filtered at 22KHz for example).
Soft dome break up occurs well within the audio range (around 8-10KHz) and relies on doping to control it.
Both types have advantages and disadvantages. Customer preference must be the factor which dictates the relative numbers of each type which are manufactured
Soft dome break up occurs well within the audio range (around 8-10KHz) and relies on doping to control it.
Both types have advantages and disadvantages. Customer preference must be the factor which dictates the relative numbers of each type which are manufactured
Hi nigelb63 I can think I can help with the Coles models. (This is Coles Electroacoustics you're referring to, correct?). I understand the mylar unit you have in mind to is the 19mm 'super tweeter'. This is the old (very old!) STC 4001 (now CE4001) unit (early Spendor BC1,2 and 3, B&W DM2a, IMF, Rogers etc). I think I'm right in saying that it began life as the diaphragm of one of their (STC) microphones and then it had its purpose reversed, i.e. emitting sound rather than capturing it. Coles bought the tooling. The other tweeter they sell is the CE3000 which is the old Celestion HF1300 with a new faceplate/mounting plate.
If you wish to follow these units up the guy to speak to is called Royal and he's active on the forum of 'hifiloudspeakers' a UK website dedicated to early KEF units and systems.
If you wish to follow these units up the guy to speak to is called Royal and he's active on the forum of 'hifiloudspeakers' a UK website dedicated to early KEF units and systems.
Last edited:
I guess there are some bad examples of both metal domes and soft domes,
But to be honest, I am listening to both, every day, and have no complaints.
(JBL titanium domes, in my XPL 200`s. And Morel 28mm soft domes in my car)
Both are doing a very good job, without any noticeable oddities.
But to be honest, I am listening to both, every day, and have no complaints.
(JBL titanium domes, in my XPL 200`s. And Morel 28mm soft domes in my car)
Both are doing a very good job, without any noticeable oddities.
The venerable SEAS 27TDFC/G soft domed vs. 27TBFC/G aluminium (yes, they made an acoustic lens / hexagrid version of the softdome 27TDFC/G)... the 27BFC/G makes recordings with emphasis in the 2 - 4KHz range more unpleasant than the 27TDFC/G. This is using the same crossover with the 27TBFC/G (metal dome) being ~ 1dB more sensitive across the spectrum.
I preferred the soft dome in this example. The metal required more notching on these recordings to be listenable.
I preferred the soft dome in this example. The metal required more notching on these recordings to be listenable.
I think the answer on tweeters is "Nobody Knows"! 😀
Here's a speaker that might make you think. The Spendor S3/5SE:
Spendor S3/5se loudspeaker | Stereophile.com
I have heard soft dome, metal and mylar 3/4" domes that all do the top end "crashing cymbal" business extremely well. When we move into 1" tweeters, some are good, some are bad.
The other issue is crossover point and filter steepness. We all know this matters for low distortion. TBH, not many 3/4" tweeters are comfortable below 3.5kHz.
The legendary 3/4" soft dome is Hiquphon: HIQUPHON dome tweeter OWI, OWII, OWIII, OW3, OW4
Scanspeak make something similar in the D2008. SB Acoustics make a very respectable 1" metal tweeter in the SB26ADC-C000-4 :: SB Acoustics which can cross quite low.
SEAS make more goodies in their H1280-06 22TFF and H1283-06 22TAF/G style.
You will be hard-pressed to buy a good mylar tweeter these days. That rising response and impedance that played nicely with a grille cloth. Never mind Vifa and SB ring radiators. TBH, I could work with any of them. I'd just apply the legendary system7 "half-Zobel" for ultimate tweeter sweetness. 😀
Here's a speaker that might make you think. The Spendor S3/5SE:
Spendor S3/5se loudspeaker | Stereophile.com
I have heard soft dome, metal and mylar 3/4" domes that all do the top end "crashing cymbal" business extremely well. When we move into 1" tweeters, some are good, some are bad.
The other issue is crossover point and filter steepness. We all know this matters for low distortion. TBH, not many 3/4" tweeters are comfortable below 3.5kHz.
The legendary 3/4" soft dome is Hiquphon: HIQUPHON dome tweeter OWI, OWII, OWIII, OW3, OW4
Scanspeak make something similar in the D2008. SB Acoustics make a very respectable 1" metal tweeter in the SB26ADC-C000-4 :: SB Acoustics which can cross quite low.
SEAS make more goodies in their H1280-06 22TFF and H1283-06 22TAF/G style.
You will be hard-pressed to buy a good mylar tweeter these days. That rising response and impedance that played nicely with a grille cloth. Never mind Vifa and SB ring radiators. TBH, I could work with any of them. I'd just apply the legendary system7 "half-Zobel" for ultimate tweeter sweetness. 😀
Last edited:
Partly down to marketing expectations, metal must sound hard and the soft or fabric domes must sound soft/smooth
While on the subject of tweeter breakup, KEF and B&W use a stiffened 'double dome' design that appears to be very effective, pushing the breakup of a 1" aluminum dome to about 40khz (confirmed by independent measurements), higher than many beryllium domes.
kef-stiffened-tweeter-dome
zaphaudio-KEF-CSD
kef-stiffened-tweeter-dome
zaphaudio-KEF-CSD
Last edited:
This stiffened aluminium dome business is actually something called anodising.
SB Acoustics call it "ceramic":
SB Acoustics :: SB26CDC-C000-4
But we know it's a way of adding a layer of oxide to the aluminium. The oxide layer is actually more rigid than aluminium metal. SEAS do it to some metal midbasses too.
Pushes the breakup beyond 27kHz. I'm not sure I really care about frequencies so high, but who knows. You pays your money and you makes your choice! 😀
SB Acoustics call it "ceramic":
SB Acoustics :: SB26CDC-C000-4
But we know it's a way of adding a layer of oxide to the aluminium. The oxide layer is actually more rigid than aluminium metal. SEAS do it to some metal midbasses too.
Pushes the breakup beyond 27kHz. I'm not sure I really care about frequencies so high, but who knows. You pays your money and you makes your choice! 😀
This is clear. But I guess it is not very relevant because a harmonic at 25 kHz caused by a 12.5 kHz input signal can't be heard IMO. But maybe someone can convince me of the contrary. Regarding IMD it might look different probably.
Regards
Charles
IMD is the main question; depends on the inherent motor & suspension linearity (i.e. how low HD is in the audio band) & the size of the breakup / bell mode. It may be an issue, it may not; as always, no fixed answer to that, just one that varies according to driver characteristics. On the whole, it's not unreasonable to say that the closer an ultrasonic breakup peak is to the audio band, the greater the chances become of it causing problems, but this is not a given or anything like.
Thanks for all responses. Steve, System 7 sums up pretty well. He cares not- he has a Zobel that will present the sound he wants from a speaker. Also, I have to say thanks and gratitude to Steve, with my project and Dave Bullet. Steve understands that few on here understand that not all members are familiar with the empirical language used. Steve has mentored me and has a great skill when articulating a response to my question.
That's not to say that I am ungrateful, I am very, but I'm a pragmatic learner.
Here's a thing. The Coles mylar tweeter was all of the rage. They have only two models, compared to everyone else. With the resurgence of vintage HiFi- will we see a resurgence of the classic KEF's that used them?
That's not to say that I am ungrateful, I am very, but I'm a pragmatic learner.
Here's a thing. The Coles mylar tweeter was all of the rage. They have only two models, compared to everyone else. With the resurgence of vintage HiFi- will we see a resurgence of the classic KEF's that used them?
Hello nigelb63,
A Zobel does not do anything to remedy the acoustic output imperfections of a dome tweeter or any other driver for that matter; it merely flattens the impedance above the Fo peak. The standard Zobel is just a simple RC network.
And yes, before others jump in , it is also possible to flatten out the Z-peak at resonance, but that requires a more complex LCR network.
On a side note: the Coles 4001 's I had in my PRO9 TL's back in 1977-1988 did not add anything audible. Just listening to the Audax HD12x9 without the Coles made no difference whatsoever. So I threw out the Coles..
A Zobel does not do anything to remedy the acoustic output imperfections of a dome tweeter or any other driver for that matter; it merely flattens the impedance above the Fo peak. The standard Zobel is just a simple RC network.
And yes, before others jump in , it is also possible to flatten out the Z-peak at resonance, but that requires a more complex LCR network.
On a side note: the Coles 4001 's I had in my PRO9 TL's back in 1977-1988 did not add anything audible. Just listening to the Audax HD12x9 without the Coles made no difference whatsoever. So I threw out the Coles..
- Status
- Not open for further replies.