Thank you Profiguy for your detailed and thoughtful response.
I also suspect the dome geometry of a cd diaphragm to be far less than appropriate for a direct radiator dome. But this is only my suspicion from reading about dome structures. My motivation for using a metal dome is to build up an XPL200 (JBL) as l have the woofers already and the 115H-1 can be obtained from eBay. Even through the dome in that design operated from 1.1Khertz to 4.5 khertz it was obviously used for a reason. A lower mid driver was used from 400 hertz to 1.1 hertz
This brings me to the diy quandary is a dome better used over a limited range than a wide range if this posses a costly engineering challenge.
I felt this was an interesting insight from a system design perspective. From a diy perspective are we better off looking at the SB acoustic 60mm soft some or the Dayton domes for use over a limited range?
Food for thought.
My intuition is that accuracy in the midrange 400-4000 hertz poses conflicting transducer requirements of displacement at 400 hertz versus break up at 4000 hertz. Low distortion and piston range mean a stiff, damped and light weight material.
While a 1.1 khertz might seem a compromise it may not be if a complimentary compromise of the above is found.
https://www.audiophilenirvana.com/audiophile-equipment-reviews/jbl-xpl-200a-holy-grail/
I also suspect the dome geometry of a cd diaphragm to be far less than appropriate for a direct radiator dome. But this is only my suspicion from reading about dome structures. My motivation for using a metal dome is to build up an XPL200 (JBL) as l have the woofers already and the 115H-1 can be obtained from eBay. Even through the dome in that design operated from 1.1Khertz to 4.5 khertz it was obviously used for a reason. A lower mid driver was used from 400 hertz to 1.1 hertz
This brings me to the diy quandary is a dome better used over a limited range than a wide range if this posses a costly engineering challenge.
I felt this was an interesting insight from a system design perspective. From a diy perspective are we better off looking at the SB acoustic 60mm soft some or the Dayton domes for use over a limited range?
Food for thought.
My intuition is that accuracy in the midrange 400-4000 hertz poses conflicting transducer requirements of displacement at 400 hertz versus break up at 4000 hertz. Low distortion and piston range mean a stiff, damped and light weight material.
While a 1.1 khertz might seem a compromise it may not be if a complimentary compromise of the above is found.
https://www.audiophilenirvana.com/audiophile-equipment-reviews/jbl-xpl-200a-holy-grail/
@profiguy : I tried this afternoon to remove the cavity cone of one of my SATORI MD60N-6... No way ! 😒
I removed the three Allen 2mm screws, but the cavity cone did not wanted to dismantle. I think that there is a sealing gasket, which may probably glued in between... 🤔
Understandably, I did not insisted further : so my apologies, but the mystery will remain... 😕
T
I removed the three Allen 2mm screws, but the cavity cone did not wanted to dismantle. I think that there is a sealing gasket, which may probably glued in between... 🤔
Understandably, I did not insisted further : so my apologies, but the mystery will remain... 😕
T
@tubelectron By all means don't risk damaging them. My first pair a few years back weren't sealed that way and literally came apart in my hands after the three screws were removed. Yours must be put together a little different being newer. There is a gasket on them but it looks like they may have gone to a permanent adhesive seal. Thank you for trying!
Yes. That's possible... SBAcoustics do not want their "Secret" to be unveiled too easily anymore ! 🙄 😉
T
Well, I wouldn't suspect that dome mid to be that much of a secret since I already noticed from mine that SB copied the SS D7608 diaphragm layout with the screen behind it with the aperiodic flow resistance dampening. Its a good mid dome but nothing special design wise.
My exspirience is that my 2 inch D54 dome is best used above 1 KHz. even it it can on paper go somewhat lower. These dome's do not have a lot of cm2 to move air and not much Xmax. A 2 inch dome mid. can go up to 5 - 6 Khz so you have basicly a two way + supertweeter with the benefit of covering 40 Hz - 5 KHz by two units. In my case a 8 inch woofer. Add a subwoofer and you have a ( semi) two way which covers 30 Hz - 20 KHz.
@tubelectron The big benefit of the MD60N is its sensitivity and smooth upper mid breakup. If you cross above 1k, it will do well and you'll avoid most of the less desirable quirks. Don't get me wrong, its a nice dome mid and compares favorably to the other middle of the road drivers in its class. I still prefer the sound profile of the MDM55 but the lack of sensitivity makes it less desirable unless you're building an average sensitivity 3 way with a typical 8" or very good 10" like Seas, Dayton Reference or ScanSpeak.
I have an open baffle design in mind with 2x Peerless NE315W, 1x NE180W, 1x Morel MDM55 and CAT308. The NE series blends very well with the Morel domes. The MDM55 has a very natural, smooth character which doesn't embellish at all and only plays what's there without mercy to any flaws in the time domain or acoustical balance. Any recording with rough midrange is hard to listen to over this mid. There's a reason why they still build the driver. One is the car sound market and the other is for use in studio monitors. Just don't cross it under 800 hz 3rd order or 1000 hz 2nd order and you'll get the best.out of it.
I have an open baffle design in mind with 2x Peerless NE315W, 1x NE180W, 1x Morel MDM55 and CAT308. The NE series blends very well with the Morel domes. The MDM55 has a very natural, smooth character which doesn't embellish at all and only plays what's there without mercy to any flaws in the time domain or acoustical balance. Any recording with rough midrange is hard to listen to over this mid. There's a reason why they still build the driver. One is the car sound market and the other is for use in studio monitors. Just don't cross it under 800 hz 3rd order or 1000 hz 2nd order and you'll get the best.out of it.
I see - Thanks @profiguy ! You pretty summed it up...
The Morel MDM55 :
Well, I looked at it also (following recommendations found in the thread), and I hesitated...
This superb Midrange dome has the advantage to be compact, therefore offering to reduce the distance between the Tweeter and the Midrange. It offers a low Fs combined with a nice linearity, but an efficiency at 89.5dB/W/m, according to its specs :
In comparison, the SBAcoustics SATORI MD60N-6 is indeed less favourable in dimensions, but it offers a 94dB/W/m sensivity for a quite similar frequency response in the 1kHz to 10kHz range.
The least sensitive of my speakers is the 12" BEYMA 12BR70 at 93.5dB/W/m, that is to say +5dB over the Morel MDM55 : that's why I preferred to chose a matching sensivity, hence the SATORI MD60N-6...
I possibly could have count on a baffle step effect to help the sensivity of the Morel MDM55, since my 475L project offers a quite large frontface :
For the better or for the worse, I did not wanted to take the risk of an imbalance of sensivity impossible to correct afterwards... 😕
T
The Morel MDM55 :
Well, I looked at it also (following recommendations found in the thread), and I hesitated...
This superb Midrange dome has the advantage to be compact, therefore offering to reduce the distance between the Tweeter and the Midrange. It offers a low Fs combined with a nice linearity, but an efficiency at 89.5dB/W/m, according to its specs :
In comparison, the SBAcoustics SATORI MD60N-6 is indeed less favourable in dimensions, but it offers a 94dB/W/m sensivity for a quite similar frequency response in the 1kHz to 10kHz range.
The least sensitive of my speakers is the 12" BEYMA 12BR70 at 93.5dB/W/m, that is to say +5dB over the Morel MDM55 : that's why I preferred to chose a matching sensivity, hence the SATORI MD60N-6...
I possibly could have count on a baffle step effect to help the sensivity of the Morel MDM55, since my 475L project offers a quite large frontface :
For the better or for the worse, I did not wanted to take the risk of an imbalance of sensivity impossible to correct afterwards... 😕
T
@Henk Haring One benefit of a higher sensitivity mid is the ability to pair it with the resulting higher sensitivity of using multiple medium sized woofers and still having the ability to linearize them on a narrow baffle with a passive xover. The driver also doesn't have to work as hard to stay linear from a power compression aspect. Higher power levels needed for more output with lower sensitivity drivers also increase non linear distortion mechanisms down low, including IMD. A more sensitive driver will usually be slightly more transparent. This isn't a hard rule and requires looking at multiple driver parameters, but it does appear to correlate this reasoning based on my experiences with higher sensitivity drivers, specifically smaller midrange drivers.
Most of the so called magic detail and downward resolution occurs in the quieter passages of music, occupying the equivalent power range just under the transition point to class B operation on a typical class AB amplifier. Staying in that power range will usually provide the lowest average amount of HD and the widest FR at flatter phase from an amplifier induced POV. Higher sensitivity allows you to stay mostly in the sweet spot of that average listening level just under the one or two watt range.
Modern, well designed class D can sound decent, but it always seems to be a little bit lacking, grittier and less precise sounding than a well designed class A or excellent class AB design. This is even more the case when employing more modern, discrete bipolar output devices and driven by J-FETS / lateral FETs. Obviously, vacuum tubes can get you there as well but these are usually noisier, less consistent and less reliable.
Most of the so called magic detail and downward resolution occurs in the quieter passages of music, occupying the equivalent power range just under the transition point to class B operation on a typical class AB amplifier. Staying in that power range will usually provide the lowest average amount of HD and the widest FR at flatter phase from an amplifier induced POV. Higher sensitivity allows you to stay mostly in the sweet spot of that average listening level just under the one or two watt range.
Modern, well designed class D can sound decent, but it always seems to be a little bit lacking, grittier and less precise sounding than a well designed class A or excellent class AB design. This is even more the case when employing more modern, discrete bipolar output devices and driven by J-FETS / lateral FETs. Obviously, vacuum tubes can get you there as well but these are usually noisier, less consistent and less reliable.
Depending on the width and Q of the passband voltage gain can occur in a passive network of a midrange driver. I have measured 2 db of voltage gain in passband with crossover points of 300 and 1300 hertz.
Yes, the bandpass amplitude gain created by filter Q addition and overlapping response with the LF.and HF drivers can be as high as several dB. This needs to be accounted for in estimated driver base sensitivity, chosing driver types accordingly. The closer the xover frequencies are, the higher the gain.
If we look at the hard numbers of distortion, noise levels, frequency response, power output, dynamic range ect. A good class D amp does perform at least as good or better then most class A, AB or not even to speak about tube amps. On a subjective level, our brain gets used to a “type” of sound and adapts to that. My subjective experience with my class A tube amp, 2x 30 watt (15 kg), my vintage AB Toshiba SB620 (14 kg) and my el cheapo Aiyima 07 (0,5 kg) is that all perform very well but the Aiyima has a better bass control which results in a more clean and neutral total image. Not far behind was the tube amp and the Toshiba was less controlled.
This is why bi amp of a woofer is such a cool idea in our diy scene.
You get to use amplifiers that work well in their respective roles and it removes the need to have a mid and tweeter at least as efficient as the woofer.
Don’t wanting to push someone’s design but l did evaluate Nelson’s 24 db crossover which originally used Fairchild Jfets and it’s hands down brilliant. No chip sound in these active filters what so ever. Grab one of the kits and give it a go. Grey Rollins has written a few articles on Jfet discrete active crossovers.
I tend to agree that at low levels the crossover distortion from A to B can be a problem.
But a biased class A design has only some 2nd harmonic but no high order. Earl Geddes research suggest the ear is more susceptible to detecting high order distortion at low amplitude while it is less susceptible to 2nd order at high amplitude.
This was revealed on a YouTube featuring Earl who l have a lot of respect as he is independent of any of the larger players like Samsung- Harman. I’m not bashing Harman but Earl tells us how the “Ear” actually works. I think Nelson Pass has made similar findings with the spread of distortion harmonics at low and high amplitude levels.
Anyway enough of my waffle. I’m off for a Sunday morning coffee ☕️
https://www.firstwatt.com/wp-content/uploads/2023/12/art_lxmini-crossover.pdf
You get to use amplifiers that work well in their respective roles and it removes the need to have a mid and tweeter at least as efficient as the woofer.
Don’t wanting to push someone’s design but l did evaluate Nelson’s 24 db crossover which originally used Fairchild Jfets and it’s hands down brilliant. No chip sound in these active filters what so ever. Grab one of the kits and give it a go. Grey Rollins has written a few articles on Jfet discrete active crossovers.
I tend to agree that at low levels the crossover distortion from A to B can be a problem.
But a biased class A design has only some 2nd harmonic but no high order. Earl Geddes research suggest the ear is more susceptible to detecting high order distortion at low amplitude while it is less susceptible to 2nd order at high amplitude.
This was revealed on a YouTube featuring Earl who l have a lot of respect as he is independent of any of the larger players like Samsung- Harman. I’m not bashing Harman but Earl tells us how the “Ear” actually works. I think Nelson Pass has made similar findings with the spread of distortion harmonics at low and high amplitude levels.
Anyway enough of my waffle. I’m off for a Sunday morning coffee ☕️
https://www.firstwatt.com/wp-content/uploads/2023/12/art_lxmini-crossover.pdf
Last edited:
I have mixed feelings about people claiming to be experts, telling me what is or isn't detectable by the ear as a hard fast rule. Its been sort of beaten into the ground for me and has caused alot of arguments based on this theory. Everyone has different taste and preference in what they musically prefer along with the psychology behind their reasoning. The statement that our ears all respond the same to specific types and combinations of distortion, FR imbalance and other anomalies isn't valid for all of us despite what some people claim. It depends on quite a few variables, some of which aren different from one person to the next.
I'll agree to a point that class D will do better quality LF for the same budget as class AB, B or multi tier H. I’ve owned a few cheaper chip based class D amps which can be surprisingly decent at average output levels. I use Icepower based plate amps for subs and they sound fantastic. They aren't cheap though and you get what you pay for in most cases. I don't use any of the usual vintage Japanese lower powered amps or receivers alot of DIY people prefer. They just don't perform well in the noise department and have elevated, rather audible distortion issues. My main amp is a Parasound JC5, which to my ears is an excellent example of a well designed high bias class AB amp. I'd rate it in the same league as a Pass X250. Most people haven't experienced a higher end speaker played through an honest low compromise class A or high bias AB amp.
The midrange is a delicate and critical area which reveals alot of nuances. Specifically 300hz - 10k has to be treated very carefully and should always be prioritized in any decent system. Going further, the 2 - 5k area is even more delicate and should be ideally covered by a single driver. The lower mids from 300 - 1000 hz will reveal even the slightest non linear, odd order distortion components. Any subtle issues here will stand out like a sore thumb, specifically crossover distortion.
2nd order HD is more pleasant but despite this, there's a limit here to what sounds accurate and natural. The amplifier plays a big role as to what is actually audible. Most push pull output amps don't have low enough overall distortion levels to allow for the audible detection of residual odd order HD. In theory, according to the experts, most (if not all) of us shouldn't be able to discern such small levels of odd order HD by ear, but you'll be very surprised to find out you actually can hear it. A tenth of a percent is easily detected by an educated listener. It may require careful listening with a fresh pair of ears, but it can be detected repeatably with confidence in most cases with the right music. Many higher end amps have audible levels of odd order, non linear HD higher than some of the best speakers available. Alot of the mid drivers on the DIY market are capable of very low HD. Higher end DIY designs using these drivers can pull off vanishingly low amounts of odd order HD. They're often revealing enough in the mids to draw negative attention to these minute levels of distortion typically buried by lesser quality speakers. There have been many occasions where a basic 2 way speaker could expose minute HD issues between different models of amplifiers, proving that some amps are better than others.
I'll agree to a point that class D will do better quality LF for the same budget as class AB, B or multi tier H. I’ve owned a few cheaper chip based class D amps which can be surprisingly decent at average output levels. I use Icepower based plate amps for subs and they sound fantastic. They aren't cheap though and you get what you pay for in most cases. I don't use any of the usual vintage Japanese lower powered amps or receivers alot of DIY people prefer. They just don't perform well in the noise department and have elevated, rather audible distortion issues. My main amp is a Parasound JC5, which to my ears is an excellent example of a well designed high bias class AB amp. I'd rate it in the same league as a Pass X250. Most people haven't experienced a higher end speaker played through an honest low compromise class A or high bias AB amp.
The midrange is a delicate and critical area which reveals alot of nuances. Specifically 300hz - 10k has to be treated very carefully and should always be prioritized in any decent system. Going further, the 2 - 5k area is even more delicate and should be ideally covered by a single driver. The lower mids from 300 - 1000 hz will reveal even the slightest non linear, odd order distortion components. Any subtle issues here will stand out like a sore thumb, specifically crossover distortion.
2nd order HD is more pleasant but despite this, there's a limit here to what sounds accurate and natural. The amplifier plays a big role as to what is actually audible. Most push pull output amps don't have low enough overall distortion levels to allow for the audible detection of residual odd order HD. In theory, according to the experts, most (if not all) of us shouldn't be able to discern such small levels of odd order HD by ear, but you'll be very surprised to find out you actually can hear it. A tenth of a percent is easily detected by an educated listener. It may require careful listening with a fresh pair of ears, but it can be detected repeatably with confidence in most cases with the right music. Many higher end amps have audible levels of odd order, non linear HD higher than some of the best speakers available. Alot of the mid drivers on the DIY market are capable of very low HD. Higher end DIY designs using these drivers can pull off vanishingly low amounts of odd order HD. They're often revealing enough in the mids to draw negative attention to these minute levels of distortion typically buried by lesser quality speakers. There have been many occasions where a basic 2 way speaker could expose minute HD issues between different models of amplifiers, proving that some amps are better than others.
Hi there all,
This is my first post in "The dome midrange thread", and I haven't read all previous posts.
I thought I should add some thoughts regarding the 'classic ATC dome midrange'.
Many years ago I had the opportunity to A/B listen to a very expensive 'top line' ATC speaker against the 15" Tannoy Arden.
I didn't like the midrange sound of the ATC's at all. I have always assumed that it could have been a crossover issue BUT >
at the price-point, why would a crossover be wrong ?
What are your thoughts regarding this A/B test ???
https://atc.audio/soft-dome-mid-range/
This is my first post in "The dome midrange thread", and I haven't read all previous posts.
I thought I should add some thoughts regarding the 'classic ATC dome midrange'.
Many years ago I had the opportunity to A/B listen to a very expensive 'top line' ATC speaker against the 15" Tannoy Arden.
I didn't like the midrange sound of the ATC's at all. I have always assumed that it could have been a crossover issue BUT >
at the price-point, why would a crossover be wrong ?
What are your thoughts regarding this A/B test ???
https://atc.audio/soft-dome-mid-range/
put this dome behind a 2 inch big horn and you could have a very nice mid driver from 600 to 6K 😉