If the drivers are mounted magnet-to-magnet, I think the theory is that Bl(x), Le(x), and any other f(x) will average together for the two woofers and the result would be superior to a single woofer. This is not cancelling, but an averaging of the asymmetric behavior. This is the theory...
I have mixed feelings on this. I am not entirely convinced that the theoretical benefits of isobaric are actually achieved. It seems there is some amount of handwaving in this theoretical explanation. On the other hand, the two isobarics I heard at the InDiyanna event sounded very good without any of the typical 2-way upper midrange congestion. Two observations don't make a trend, but they can't be dismissed either. It is entirely possible that there is something else at work here, and the isobaric architecture has an as-yet-unidentified benefit. It is also possible that the two I heard were just really well engineered 2-ways.
j.
I have mixed feelings on this. I am not entirely convinced that the theoretical benefits of isobaric are actually achieved. It seems there is some amount of handwaving in this theoretical explanation. On the other hand, the two isobarics I heard at the InDiyanna event sounded very good without any of the typical 2-way upper midrange congestion. Two observations don't make a trend, but they can't be dismissed either. It is entirely possible that there is something else at work here, and the isobaric architecture has an as-yet-unidentified benefit. It is also possible that the two I heard were just really well engineered 2-ways.
j.
They most definitely don't.
I have heard systems with the best drivers out there that just sounded like an absolute turd.
It doesn't say anything at all if you don't know how well the directivity is, and good the crossovers are done etc etc.
Not to talk about the room/environment and so many other variables.
I for one, never understood specific claims when people "heard something out there" that sounded great and therefor it MUST be that one and only specific thing making it performing so well.
I don't doubt the experience, but I have an hard time believing that just one specific solution is making or breaking things.
It's all about how well it's being implemented.
For the benefits from magnet-to-magnet, one could also make a impulse-corrected enclosure.
Which actually has a lot of other nice benefits.
Btw, the "averaging" effect again doesn't really work anymore for very well made woofers with very symmetrical behavior.
Or a better way of saying it, it doesn't have any benefits anymore.
But as far as I know, distortion elements always sum, never average.
If you cancel out inequalities between cone moving outwards and cone moving inwards that is reduction of H2.
(Edit: that may just be my very simplified understanding ... correct me if I'm wrong!)
Probably true with modern drivers. But it might still be a useful technique to extract performance from a $39 woofer which is technologically equivalent to a 1985 Peerless or Audax woofer.
From the standpoint of objective, technical measurements, dome midranges don't have many advantages over midrange cones, and they have several disadvantages. The dome mid often has a high sensitivity, and this is it's one big compelling advantage. But on the down side, the Fs is usually in the 200 - 400 Hz range, and this complicates passive crossover design. Even in an active design, it forces the crossover point to be fairly high... typically 500 - 900 Hz. Cone mids tend to have an Fs in the 40 - 100 Hz range, which is far easier to work with. Domes tend to be more expensive. Domes have a narrower bandwidth (as a result of the high Fs). If the application requires a midrange to run from 250 Hz to 2.5k, domes need not apply (except perhaps for the new Bliesma 140mm dome). If the bass driver is a 15" unit, there may be very good reasons for keeping the lower crossover as low as possible...
From a subjective standpoint, it is possible that dome midranges provide a different kind of listening experience. Perhaps they just sound better, for reasons we don't yet understand. I intend to explore this someday, with either the Volt driver or the Bliesma 74mm driver.
Domes are more common in studio midfield monitors and main monitors than they are in high end home hifi. This may be due to the higher sensitivity offered by the dome mid, but it may also be due to fashion. Domes are fashionable, and musicians and studio engineers are people too, and people shop with their eyes as well as their ears. People are influenced by biases and inertia. If I was going into the business of building an active 3-way midfield monitor for the professional market, I would strongly consider a dome midrange... not because I think it is better, but because I think it would sell better.
Your statement that "For me on a personal level, the only REAL midrange driver that’s acceptable for home hifi and critical monitoring is the dome"... I respect that. We all make choices. I can say with confidence that both the Satori MW16TX-4 and the Purifi PTT6.5M04-NFA-01 are very high quality midrange transducers in the range from 200 - 2k. For me, they are REAL midrange drivers.
j.
Domes have a (very) different directivity compared to woofers.
The main benefit I see, is more in the sense of lack of cabinet issues.
Good ones also seem to have better distortion, but I say that with a asterisk lol
(I haven't looked at them in a while)
But like you already said, it's difficult to find ones that can be crossed much lower.
Which I think it definitely possible, but there is just no market for it.
(People just love their traditional 3-way systems)
In the end it's just a different way of producing sound.
Each way has its pros and cons.
Thanks Jim……subjectively is purely my approach here. I can state unequivocally from personal experience that acoustic theory and measurements are just a scratch on the surface of understanding what we enjoy from sound reproduction. As a recording mix and live sound engineer, my first experience with an ATC monitoring system Equipped with their dome mid was a revelation…..I highly suggest everyone try it……it just might become your own personal reference going forward.
But again, some will argue that it was the entire system and NOT just the dome, but I beg to differ…..when a professional trained ear listens within a passband and it’s the dome radiating in that passband there’s just no other explanation. Subjectivity is at least a seven headed monster once you start exposing all of the attributes that people may apply as good, better or best. Take the visual aspect out of it and subjectivity gets obliterated by expectation bias……..like a pile of high end drivers and crossover components sitting on a table waiting to be put into a system……the more you look at them, the better they sound!
Had an experience with a Purifi 6.5…..nice driver….easy to work with and very low energy storage. And playing complex harmonic content, it sounds it……….very polite.…….sometimes a little sass is preferred you know?……some days black fishnets are more attractive than a grand ball gown. To each their own I suppose.
Every once in a while, a product achieves legendary status. And most of the time, there's a combination of factors that lead to its status.
It’s usually time that allows us to understand these things. Revisionist history.
Like the Yamaha NS10, brought into the states by Bob Clearmountain as his own personal monitor. Story goes that he visited different studios with this relatively portable 6.5“ sealed box 2 way. So who could blame people for looking to see what his advantage was, and outfitting studios with the NS10. Hint, it was‘t the NS10 specifically- but it was a portable compact speaker that HE was intimately familiar with. Other producers would have to try to get accustomed to sound from wildly different in monitors, in wildly different placement settings and acoustical environments.
The ATC SM75-150S 3” mid dome has a great combination of high sensitivity, low distortion and smooth response.
Objectively, we know that between 400Hz and 3KHz there were few others that can compete. At least not when it was released in the 1970s. Also helped by the fact that ATC were made exclusively for big studios, and the late Billy Woodman really pushed active biamped or triamped speakers in really large cabinets, long before it was in (and long after it was out of) fashion. Apart from technical benefits, it matched the correct amplifiers for the job, rather than let the installer choose the right/wrong amp.
I like their 200+ litres one’s, with 15” woofer, or the twin 12” or twin 15” woofers.
It deserves its place in the history books. Certainly a nice museum piece, with its gargantuan ferrite magnet, unique look of convex dome + concave waveguide assembly, and exposed wires to the voice coil.
I know the late Jeff Bagby did a design about a decade ago, and was rather impressed after taking measurements. the matched up with what John Krutke has found earlier. Which was a 3” soft dome with VERY low harmonic distortion.
I’m happy to bet (and fund/organise) that if you put that thing on an Klippel you’ll find a a rather flat and symmetrical Kms(x).
So apart from that tiny dip at 3.8K, and the after-market “spare parts” pricing (ie. obscene pricing), there’s really wasn’t much to complain about! Near perfection for a small fortune.
in your own your designs, what cones have you tried and what woofers or tweeters did you match them to?
What were you not happy?
some interesting developments in transducers have occurred in the decade, and will do so in the future, thanks to computer based modelling and rapid prototyping. there will be better understanding of the relative importance of directivity matching and diffraction control. The ATC 3” mid dome will be surpassed. (or has been)
No need to lust after the NLA SM75-150S. Though many will, purely because of the unobtainium status.
It’s usually time that allows us to understand these things. Revisionist history.
Like the Yamaha NS10, brought into the states by Bob Clearmountain as his own personal monitor. Story goes that he visited different studios with this relatively portable 6.5“ sealed box 2 way. So who could blame people for looking to see what his advantage was, and outfitting studios with the NS10. Hint, it was‘t the NS10 specifically- but it was a portable compact speaker that HE was intimately familiar with. Other producers would have to try to get accustomed to sound from wildly different in monitors, in wildly different placement settings and acoustical environments.
The ATC SM75-150S 3” mid dome has a great combination of high sensitivity, low distortion and smooth response.
Objectively, we know that between 400Hz and 3KHz there were few others that can compete. At least not when it was released in the 1970s. Also helped by the fact that ATC were made exclusively for big studios, and the late Billy Woodman really pushed active biamped or triamped speakers in really large cabinets, long before it was in (and long after it was out of) fashion. Apart from technical benefits, it matched the correct amplifiers for the job, rather than let the installer choose the right/wrong amp.
I like their 200+ litres one’s, with 15” woofer, or the twin 12” or twin 15” woofers.
It deserves its place in the history books. Certainly a nice museum piece, with its gargantuan ferrite magnet, unique look of convex dome + concave waveguide assembly, and exposed wires to the voice coil.
I know the late Jeff Bagby did a design about a decade ago, and was rather impressed after taking measurements. the matched up with what John Krutke has found earlier. Which was a 3” soft dome with VERY low harmonic distortion.
I’m happy to bet (and fund/organise) that if you put that thing on an Klippel you’ll find a a rather flat and symmetrical Kms(x).
So apart from that tiny dip at 3.8K, and the after-market “spare parts” pricing (ie. obscene pricing), there’s really wasn’t much to complain about! Near perfection for a small fortune.
in your own your designs, what cones have you tried and what woofers or tweeters did you match them to?
What were you not happy?
some interesting developments in transducers have occurred in the decade, and will do so in the future, thanks to computer based modelling and rapid prototyping. there will be better understanding of the relative importance of directivity matching and diffraction control. The ATC 3” mid dome will be surpassed. (or has been)
No need to lust after the NLA SM75-150S. Though many will, purely because of the unobtainium status.
It's mostly thanks to better and cheaper manufacturing as well as patents that have been expired.
Even very cheap drivers from brands like Dayton (and many others) outperform some very $$$$ drivers from two-three decades ago with ease.
To be very honest, I haven't seen that many ground breaking developments the last years at all.
More just improvements on stuff that was already known but most companies couldn't be bothered about it.
Or have been locked up by a whole bunch of patents.
Quite a few loudspeaker manufactures are just pretty conservative and stubborn, just staying where they are.
Which is sad, because if you purely look at production and sales costs and difficulty, it wouldn't be hard at all to produce a speaker that does 85% of the performance of a Purifi for 15% of the price.
Maybe actually even more if the production numbers are high enough and leave out all the aesthetic fluff.
(looks really nice, but doesn't do anything performance wise)
well said @tktran303
I don't mind paying Purifi price for Purifi performance. If what they are doing was so obvious and simple, why was it not done before at a substantially lower price... 15% as you say?
The free market is not instantaneously 100% efficient, but given enough time, prices are a very accurate reflection of where the customer desire/need meets the suppliers capacity to deliver. The idea that there is low hanging fruit in making better drivers (or any product) at a cheaper price doesn't pass the smell test. Making something both better and cheaper is very very hard.
I don't mind paying Purifi price for Purifi performance. If what they are doing was so obvious and simple, why was it not done before at a substantially lower price... 15% as you say?
The free market is not instantaneously 100% efficient, but given enough time, prices are a very accurate reflection of where the customer desire/need meets the suppliers capacity to deliver. The idea that there is low hanging fruit in making better drivers (or any product) at a cheaper price doesn't pass the smell test. Making something both better and cheaper is very very hard.
I can't answer the question WHY nobody is doing it for a lower price.
Although I already gave a few ideas why that could be.
But if you know something about mechanical construction and how much certain aspects cost, also in sense of production scale, than it's not hard to understand that the price can go down substantially.
For example you can make CNC a loudspeaker basket out of fancy materials, or just make a mold for sturdy reinforced plastics or use stamped frames.
All of those can results in a extremely nice performing speaker (plenty of examples out there), but the first one is a lot more expensive.
Get things better AND cheaper is just a matter of scaling, but it's absolute not true that it's not possible.
You can sell 5 pieces of fruit for 400 bucks each, or sell 100 pieces of the same fruit for 20 bucks.
The net total price is the same, although total production costs usually goes down (drastically) when scaling up.
If you have the facility and you're smart, you sell the 100 pieces for 40 bucks instead, gaining a awful lot more profit.
(in fact, you just doubled)
Which you could use for more and better development for example.
I think we’re all agreeing that quality will go up and prices will go down with time. It just doesn’t happen straight away.
For example, I considered myself late to the class D party- because some people were already enjoying the Hypex UcD stuff in early C21, soon after mass production started in 2004 IIRC (Ucd180)
In fact, it was @mac who recommended it to me against the tide of class D naysayers. I waited awhile, and got the Hypex nCore400 in 2012.
Now; almost 20 years later, we are on the verge of high performance, very affordable, Class D (ie. TI TPA3255 with PFFB). So in 2023-24, you can/will be able to can get very good/close to the same performance as Bruno Putzey’s UcD180, for cheaper.
20 years!
Similarly, one can criticise Scan-Speak for their prices. But you can’t criticise their performance- at least not in the mid 1980-1990s when they were the leaders.
Or… as a consumer, you can wait for the likes of Usher or Dayton Audio- In 10-20 years we’ll hopefully all have access to Purifi performance, for the price of Chinese chips.
For example, I considered myself late to the class D party- because some people were already enjoying the Hypex UcD stuff in early C21, soon after mass production started in 2004 IIRC (Ucd180)
In fact, it was @mac who recommended it to me against the tide of class D naysayers. I waited awhile, and got the Hypex nCore400 in 2012.
Now; almost 20 years later, we are on the verge of high performance, very affordable, Class D (ie. TI TPA3255 with PFFB). So in 2023-24, you can/will be able to can get very good/close to the same performance as Bruno Putzey’s UcD180, for cheaper.
20 years!
Similarly, one can criticise Scan-Speak for their prices. But you can’t criticise their performance- at least not in the mid 1980-1990s when they were the leaders.
Or… as a consumer, you can wait for the likes of Usher or Dayton Audio- In 10-20 years we’ll hopefully all have access to Purifi performance, for the price of Chinese chips.
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I won’t fill the OPs thread with any more off topic fluff on the subject of two way vs three way and domes vs cone mids other than to say this is all quite subjective and the room any system is placed in will be responsible for the majority of the performance factor.
I think far too often we all here and on other similar forums fall off the band wagon on the journey and then follow the road map of objectivity…..critical measurements, design analysis, etc…..to find that we didn’t get to the intended destination anyways. It’s important I believe to understand that when considering complex harmonic musical content along with in room acoustic variables, measurements and design guidelines don’t reveal much.….all too often the designer ends up with another box that sounds polite and does nothing wrong……but still fails to elicit any level of excitement after a few weeks of listening….just another Troels like box to look at and ask the question.
We as designers have the optimum choice of deciding on build parameters based around our intended space and use…..on a desk, up against a wall, in free space, near, mid ,far field, etc. If I know where my listening position is, id concentrat on measuring at that distance and even better IN THAT SPACE if possible. That’s the ultimate voicing of a system IMO….and yet we’ve replaced it with anechoic or infinite baffle lab measurements and simulation…….why?….are we building a commercial system than needs to sound good in a near exponential variety of environments or use cases?……. lets not forget the objective while establishing a process……other way around folks…..other way round.
I think far too often we all here and on other similar forums fall off the band wagon on the journey and then follow the road map of objectivity…..critical measurements, design analysis, etc…..to find that we didn’t get to the intended destination anyways. It’s important I believe to understand that when considering complex harmonic musical content along with in room acoustic variables, measurements and design guidelines don’t reveal much.….all too often the designer ends up with another box that sounds polite and does nothing wrong……but still fails to elicit any level of excitement after a few weeks of listening….just another Troels like box to look at and ask the question.
We as designers have the optimum choice of deciding on build parameters based around our intended space and use…..on a desk, up against a wall, in free space, near, mid ,far field, etc. If I know where my listening position is, id concentrat on measuring at that distance and even better IN THAT SPACE if possible. That’s the ultimate voicing of a system IMO….and yet we’ve replaced it with anechoic or infinite baffle lab measurements and simulation…….why?….are we building a commercial system than needs to sound good in a near exponential variety of environments or use cases?……. lets not forget the objective while establishing a process……other way around folks…..other way round.
yes they do... Measurements are crucial in getting us 95% to the success finish line. It is that last 5% that is adjusted subjectively. If we have done our jobs right, that last step of subjective voicing will be very slight adjustments of 1 dB or less. So it is important to use objective measurements and analysis to get the project nearly right, so that last bit of subjective voicing has a chance of success.
It's more like a better way to succes.
Or rather, a better way to less disappointment.