Life has sort of gotten in the way with this little project (health wise that is) and it has morphed into some other spinoff projects. God willing I'll have more time to spend on this and my main focus of design (Yuichi A290 w/ B&C DCX50 coax). The weather is finally settling down a little too.
I have some STh100s now as well with HF108s to try, but the NSD1095N + XT1086 are still on the agenda. The issue and challenge is EQing it passively with xover.
Now for 2023...
- The Faital Pro HF108 is (still) popular
- The same goes for the Tymphany DFM-2535R00-08, though availability may be problematic
- RCF ND350.
Quote from Joseph Crowe:
"Overall, I preferred the RCF. Following closely in sound quality was the Faital Pro. The RCF had more body to the vocal region and instruments sounded a little more smooth. However both drivers provided audiophile grade sound quality and I would be happy with either."
I have been using faital hf108r plus sth100 for one year. This is a great home setup, I couldn't complain. I use a little bit of shelf to boost the upper range and get a bit more air.
In ozone I use 8khz -1bd Q 4.9 low shelf
In ozone I use 8khz -1bd Q 4.9 low shelf
The soft ketone polymer that Faital uses for diaphragms sounds nice, but they tend to break up at a lower frequency than the best drivers with Titanium diaphragms > i.e. the B&C DE500 and the older RCF 1" Neo.
Tbh, I have my doubts about the 3P phase plug in the 18Sound 1" drivers.
Wrt (lack of) mid and treble details/refinement I (re)quote:
"The HF108R version has a thicker membrane and a more rigid clamping system. These details allow a more controlled movement, reducing the distortions and making less nervous and metallic the mid/high freq."
Due to the greater thickness of the already highly damped ketone polymer, the sound velocity of the material (roughly between 2000-2700 m/sec) may be too low for adequate reproduction of upper mids and treble.
For comparison:
Aluminium: 6320 m/sec
Beryllium: 12900 m/sec.
Titanium: 6100 m/sec.
Tbh, I have my doubts about the 3P phase plug in the 18Sound 1" drivers.
Wrt (lack of) mid and treble details/refinement I (re)quote:
"The HF108R version has a thicker membrane and a more rigid clamping system. These details allow a more controlled movement, reducing the distortions and making less nervous and metallic the mid/high freq."
Due to the greater thickness of the already highly damped ketone polymer, the sound velocity of the material (roughly between 2000-2700 m/sec) may be too low for adequate reproduction of upper mids and treble.
For comparison:
Aluminium: 6320 m/sec
Beryllium: 12900 m/sec.
Titanium: 6100 m/sec.
As indicated before, for me personally Be is 'too good' for use in loudspeakers.
The mismatch between high (Be), mid and low drivers is usually quite noticeable. Moreover, in my opinion Be sounds too sterile, too 'high end' and therefore unnatural.
While it may sound impressive with certain well-recorded material, it quickly becomes off-putting with less-than-great recordings.
The mismatch between high (Be), mid and low drivers is usually quite noticeable. Moreover, in my opinion Be sounds too sterile, too 'high end' and therefore unnatural.
While it may sound impressive with certain well-recorded material, it quickly becomes off-putting with less-than-great recordings.
Hi,
on a woofer, where voice coil is on the middle of the cone, sound travels via the material, reflects from the surround and back to voice coil and one would see blip in impedance plot due to back EMF, microphonics. Is this audible? Does it happen at all frequencies, or just above wavelength is short enough to size of the device? Is this the same as decoupled edge, when we see the effect in frequency response for example, edge in opposite phase as voice coil at some frequency? How is it related to a dome, where voice coil is at the edge? Longest distance for sound to travel along the material is the diameter, from one edge to another? If its 3", or 7.5cm diameter dome then sound would travel through it 2000m/s in 0,0000375 seconds, which corresponds to ~26kHz in air, seems adequate, well above hearing. Or, wavelength of 20kHz with speed of sound of 2000m/s is 2000 / 20000 = 0.1m, which is almost size of the dome. For ~6000m/s roughly 30cm, or for Be with ~13000m/s about 65cm, almost ten times diameter of the dome.
Its interesting, do you have any resources for the subject, how does this stuff work out?
on a woofer, where voice coil is on the middle of the cone, sound travels via the material, reflects from the surround and back to voice coil and one would see blip in impedance plot due to back EMF, microphonics. Is this audible? Does it happen at all frequencies, or just above wavelength is short enough to size of the device? Is this the same as decoupled edge, when we see the effect in frequency response for example, edge in opposite phase as voice coil at some frequency? How is it related to a dome, where voice coil is at the edge? Longest distance for sound to travel along the material is the diameter, from one edge to another? If its 3", or 7.5cm diameter dome then sound would travel through it 2000m/s in 0,0000375 seconds, which corresponds to ~26kHz in air, seems adequate, well above hearing. Or, wavelength of 20kHz with speed of sound of 2000m/s is 2000 / 20000 = 0.1m, which is almost size of the dome. For ~6000m/s roughly 30cm, or for Be with ~13000m/s about 65cm, almost ten times diameter of the dome.
Its interesting, do you have any resources for the subject, how does this stuff work out?
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Personally I didn't heard any metal diaphragm tweeter that didn't had some audible metallic taste/coloration to the sound (in not a good way, although that's subjective). Of course it's not noticable with every recording, but once you hear it, you know it's a metal tweeter.
Seems Be is no exception.
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What about textile/cloth? ;-)
Some may say it's the best material for a tweeter, not for a CD of course.
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It's fascinating, albeit very complex stuff. I've spent quite a bit of time reading many scientific papers on the topic of diaphragm materials - in light of the implementations > you can't just consider materials in isolation.
These subtle interactions are not usually measured with AP and similar measurement gear and - to answer your question, it's difficult to link measurable artifacts to audible effects one-to-one since we are dealing with sub-sub systems.
Clearly visible is the trend in R&D with regard to parameters/aspects that are sometimes at odds with the principles that were used in the past.
A recent example from another thread:
Quote from ‘Loudspeakers, for music recording and reproduction’ by Philip Newell and Keith Holland:
“Some manufacturers have tried to sacrifice system sensitivity by lowering the magnet flux in order to lower the system Q. There is a strong ‘amplifier power in cheap’ lobby, who believe that lower efficiency systems can exhibit higher Qs, and hence can be extended in their low frequency range. What they often seem to fail to realise is that a heavier current in the voice coil and a lower power magnet will drastically alter the ratio of the fixed magnetic field to the variable magnet field. The much higher variable field due to the voice coil current can severely distort the position of the flux lines of the weak, permanent magnet, and give rise to loss of low level detail in the sound and increased levels of intermodulation distortion.”
In my opinion, efficiency (~system sensitivity) is the most important objective in relation to 'following/replicating the input signal'.
"Apart from the phase shift that's inherent to mass-controlled woofers with 'flat' response, there's also an implicit efficiency loss and the incorrect replication of the waveshape of the input signal as byproducts, similar to 'attenuation' ".
This is the energy storage so often confused with resonances.
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Personally, I mainly use fabric (silk) dome tweeters, although I've also had good experiences with aluminum.
Here is quick overview about materials https://audioxpress.com/article/speaker-cones-fabrication-materials-and-performance
"
...
Speaker engineers know that three important physical properties determine a material’s suitability for use in loudspeaker diaphragms — stiffness, low density, and internal damping. Stiffness, in particular, determines the bending wave velocity, and for any given design, the frequencies at which the first break-up resonance occur. This resonance in a diaphragm determines the transition point above the frequency point at which the diaphragm loses piston motion and response becomes rougher.
The high Young modulus (and the steepness of the cone’s body angle and the diameter) determine at what point things become nasty. The degree of internal damping, or loss factor, determines the material’s effectiveness in suppressing such resonances, which is especially important near and above the upper resonance.
...
"
and
"
...
Young’s modulus (speed of sound), tan delta (internal damping), and mechanical parameters (e.g., tear strength, burst strength, etc.) are all factors that separate the toy cones from the audiophile, studio monitors, electric guitar, or pro sound diaphragms.
...
"
So, Young's modulus has to do with speed of sound. Young's modulus seems to measure stiffness of material per Wikipedia
From these, I would reason speed of sound in material doesn't have much to do with sound quality alone. For example geometry and damping of the material seems to be something that affects. Most likely its the combination of multiple things baked in to any speaker, and speaker system, for sound quality. Some are better set of compromises than others and there is no single parameter one could read sound quality from. Even if there was, it would have to be in context, some set of compromises works better / worse / equally well in some applications. Compression in a compression driver is probably one context that demands different set of compromises from dome than a direct radiating tweeter.
"
...
Speaker engineers know that three important physical properties determine a material’s suitability for use in loudspeaker diaphragms — stiffness, low density, and internal damping. Stiffness, in particular, determines the bending wave velocity, and for any given design, the frequencies at which the first break-up resonance occur. This resonance in a diaphragm determines the transition point above the frequency point at which the diaphragm loses piston motion and response becomes rougher.
The high Young modulus (and the steepness of the cone’s body angle and the diameter) determine at what point things become nasty. The degree of internal damping, or loss factor, determines the material’s effectiveness in suppressing such resonances, which is especially important near and above the upper resonance.
...
"
and
"
...
Young’s modulus (speed of sound), tan delta (internal damping), and mechanical parameters (e.g., tear strength, burst strength, etc.) are all factors that separate the toy cones from the audiophile, studio monitors, electric guitar, or pro sound diaphragms.
...
"
So, Young's modulus has to do with speed of sound. Young's modulus seems to measure stiffness of material per Wikipedia
From these, I would reason speed of sound in material doesn't have much to do with sound quality alone. For example geometry and damping of the material seems to be something that affects. Most likely its the combination of multiple things baked in to any speaker, and speaker system, for sound quality. Some are better set of compromises than others and there is no single parameter one could read sound quality from. Even if there was, it would have to be in context, some set of compromises works better / worse / equally well in some applications. Compression in a compression driver is probably one context that demands different set of compromises from dome than a direct radiating tweeter.
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Indeed, as stated.
For example, damping in cones has different effects/functions compared to domes in compression drivers.
Most modern woofers are inefficient, especially hi-fi woofers where η₀ is usually well below 1%.
The result of the quest for 'flat everything'. In doing so the baby is often thrown out with the bathwater.
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Kinda related, gotta mention: watched my favorite nerding YT channel recently, they've released a video about making graphene
and using it as stiffener in epoxy. In the end of the video some epoxy cast rods are bent and force measured. The rod mixed with 6% of this self made graphene requires more than 6 times the pressure than rod without any, seems crazy increase in stiffness 🙂 What if the paper cone pulp in previous AudioExpress article was mixed some, we'd get super stiff woofer cones?🙂 Possibly too expensive currently, perhaps in the future.
Why someone would pay € 429,95 for a mid with this response:
instead of spending €15 on this:
is beyond me.
instead of spending €15 on this:
is beyond me.
It's already being used:
Price: > €500 🤣
I know the ordinary magnesium Excel woofers and those leave me cold.
Price: > €500 🤣
I know the ordinary magnesium Excel woofers and those leave me cold.
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Seems to be graphene coated magnesium, thinking of normal paper cone with some graphene mixed in 😉