The other was the Xenoliths, my first attempt, and my daughter still uses them.
They were built around 2013, and theme driven for InDIYana that year. Xover was mounted on the back in a cage as it could not fit inside. Ported rather than PR, and the mids are NLA. Might be on PETT and not over here.
They were built around 2013, and theme driven for InDIYana that year. Xover was mounted on the back in a cage as it could not fit inside. Ported rather than PR, and the mids are NLA. Might be on PETT and not over here.
+1 and also cleaner upper mid low treble as well I have found, hence the little 3 ways I have made for small room. sealed, it needs the help of the room gain.
then you can use a normal 2 way (6" midbass+tweet) augmented with dual subs and highpassed (if needed of high spl)
this kind of system can rival even big 3 way speaker if perfectly done and if High Efficiency is not needed
I understand your point however
OP's system have not been disclosed i think. What Amp do you plan on using with your speakers?
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Possible but would require DSP help - boosting the range down to where the target excursion limit is reached and then adding a steep transfer function to limit overexcursion. It is indeed overexcursion that is the enemy here.
I really don't think you need to go that far unless you play at really high output levels. I've achieved some really good results for even moderate levels.
This is of course a very important topic and I have built both 2 and 3 way recently (actually 2 + sub and 3 + sub). I am a sphere speaker guy that has a great concern about minimizing diffraction effects and increasing soundstage. Spheres largely eliminate baffle issues. I also like to avoid larger cones as much as possible producing the mid or high frequencies, as the outer part of the cone itself can be a diffraction source. So I prefer domes for tweeters and mids. Metal vs. fabric? Metal is a bit sharper and has break-up issues but better transients, in general, while fabric avoids these issues. Domes also can have good off axis response. There are lots of good 1" - 3" domes available. There are also very good smaller cones (3" - 4") that address mid frequencies. As pointed out here, and I agree, for mid bass (mid-woofer) frequencies down to 100Hz or so, 5" - 6 -1/2" is probably where you need to be. For really low bass, subs are a solid option and relieve you of the larger cabinet problem for larger bass drivers. Plus you may need just one good sub to meet your low bass needs. Some larger designs have a couple bass drivers and bigger cabinets and that adds cost.
3 way can incorporate a mid driver that may be more precise in certain ways but as you point out, the crossover becomes twice as complex as you have two points to address rather than just one with a 2 way. Blending 3 drivers is harder than 2 (plus you have to buy 3 vs. 2). One of the considerations is that with domes for the mid in a 3 way, the lowest they can usually be crossover is 500-800 Hz, so that's right in the midst of the vocal range and many instruments.
So I tried a 2 way design so the 100Hz - 2000 Hz range could be done with a single driver BUT not using a 5"- 6" traditional shaped cone driver. I selected a Dynavox LW5004PMR 5 1/2" polycone (so not paper, not metal but polyester based) that can cover 100 - 2,000 Hz (and higher if you like) AND it uses a 3" VC, very uncommon. So it handles power and it has a dome configuration over the coil area, and then an outer cone to the rim surround, but overall the cone area is shallow. So the diffraction is minimized and the off axis better supported, i.e. its not "beamy" sounding in any way. The key thing is it covers the entire vocal range with a higher dispersion dome configuration while also producing the mid bass down to 100 Hz.
The next selection was an 1-1/8 fabric dome tweeter (a Dayton) that could crossover at 2,000 Hz (12 db/octave) and thereby provide the higher mids and treble with also a wider dispersion driver. Most dome tweeters can't cross as low as 2,000 Hz, but this one can. This also avoids the cone induced FR irregularities of the Dynavox that begin to occur at about 4,500 Hz and up. The overall result is a very smooth mid that you can listen to all day long and still crisp highs. The tweeter is more efficient than the midwoofer, so had to adjust with an L-Pad.
While the separate 2" mid dome in my 3 way (also a Dayton) can be a bit crisper in some situations, it can also be sharper with certain vocalists and instruments (also depends on the recording) especially at higher amplitudes. Since we are most sensitive in the mid area, there is a trade-off between a separate mid and a 2 way which may yield a smoother sound.
The 2 way portion is supplemented by an 8" sub, which gets down to about 40-45 Hz before roll off, enough to audibly reproduce well bass guitars and tympani kettles, etc. but a bigger sub of course will shake the room a bit more.
I find that 85 db (and peaks can be higher) is a safe listening level for the ears while also providing the dynamic range that makes music sound more real. While say 75 db is above "background" music, it's not enough to fill out the dynamic range. I have a typical decent size family room (20 x 20) so these fill it just fine. They could go easily above 90 db but that gets into the area of potential hearing damage especially if for any length of time. Plus the spouse or roommate may not like it so loud 🙂
So I looked for a 2 way solution (plus sub) that avoided using a traditional cone for the mids and avoided a higher crossover frequency (many speakers use 3,000 - 4,000 Hz).
Pic below but a little distorted.
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i think i disagree with everything
from your diffraction theory, to your dislike of paper cone to your love for small drivers to your 90db hearing damage.
Well, they look cool, and there are definitely specific design choices that have been implemented!
Baffle diffraction has been well documented although people do debate it, paper is better in smaller drivers less so in larger ones IMO but domes are typically not paper, and consistent levels over 90 db have been documented to risk hearing loss. An article about this from ASHA, prob. the definitive authority (my daughter is a speech, language, hearing pathologist).
https://www.asha.org/public/hearing/loud-noise-dangers/
Safe listening at 90 db may be a couple hours, but it declines rapidly as db increases. My experience is (for what its worth or not) dynamic range for home listening is good at about 85 and is safe for long periods of time.
Small drivers of course depend on the application, but plenty tweeters out there at 1".
Its about 8" or so, but I don't sit 3 feet away from them. At 10 feet, the angle at listening point of the intersecting lines emanating from the tweeter and mid woofer is less than 5 degrees.
Thx - attached is the Demand Better Audio Envy 2 - I kinda took some inspiration from them but the DBAs are expensive and have lots of hi tech aspects. The spheres are 1 mm thick carbon fiber, so you need a mold but also avoid problems of box enclosures plus they use extensive internal damping to avoid resonances (which I do as well). The woofer (I think it's about 7-8" so doesn't necessarily need a sub) shows a pretty larger dust cap "dome" to overall cone size, which I like. It's got a ribbon tweeter, pros and cons to that. A review (at least one guy's experience):
https://www.tnt-audio.com/casse/dba_envy2_e.html
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id love to read more about paper being worst the larger it gets. what is your source?
8" center to center distance between mid and treble is BIG mistake.
"hi-tech"?
even the tweeter used is a budget unit from hivi.
8" woofer doesnt need a sub?
i guess i should remove my 15" woofer from my room then
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So attached a pic of an AR 3a, still IMO one of the best 3 ways ever made. Notice the CTC on the tweeter to woofer is prob. 8 in, maybe a bit more. Or how about a Yamaha NS 10? A bit less but not much. There are plenty of good speakers with CTCs that are not 5-6". If you have an 8" woofer and stick a 1" tweeter right on top of it which will have usually a faceplate, for example, your CTC will be about 6" min. So how much does an extra 2" make at 10 feet away?
I think the Envy's tweeter is a Swan, doesn't mean it's not good.
https://www.swanspeakers.com/product/view?id=597
You can take a look at a interesting video on the Vandersteen site about cone break up, and paper is prominently referenced.
https://www.vandersteen.com/news/the-truth-about-pistonic-driver-cones
I didn't mean to say an 8" woofer doesn't need a sub, if you're okay getting down to say about 60-70 Hz, an 8 is okay. If you want lower, then add a sub.
Attachments
https://www.vandersteen.com/news/the-truth-about-pistonic-driver-cones
ive read just a few sentences
Vandersteen is out of his marble.
im shocked actually
"
Because You Need To Know The Truth About Pistonic Driver Cones …
Bringing paper cones to a super-speaker today is like bringing a horse and buggy to a Formula One race. Materials and performance have evolved and so must loudspeakers, especially at the high-price super-speaker level. Crucial to avoiding performance-killing distortion in loudspeakers are driver cones rigid enough to remain pistonic throughout their pass band, i.e., the range of frequencies each driver is required to reproduce.
“Pistonic” refers to the motion of the driver cone in response to the audio signal from the driver’s voice coil. If the driver cone stays rigid and moves in and out in truly pistonic fashion, distortion is avoided and the purest replica possible of the signal from the amplifer is produced by the speaker. If any part of the cone flexes or bends in the opposite direction of the signal, part of the cone is out of phase, and distortion is output from the loudspeaker.
In the dramatic video above, Richard Vandersteen talks through a comparison of two midrange driver cones using highly advanced imagery from a Klippel analysis. Klippel allows us to see the cones’ behavior in response to audio signals in real time and evaluate their performance. One cone is Vandersteen Audio’s “Perfect-Piston™” midrange cone, which is a patented ultra-rigid carbon-fiber/balsa core design. The other is a very expensive paper driver cone that is employed in some very high-end speaker designs …
This Is Your Driver Cone On Paper …
What’s truly shocking in this video is that so much audible distortion is readily visible at 1.4kHz with approximately half of the paper cone flexing out of phase. 1.4kHz is of course well within the crucial midrange frequencies this driver cone would be expected to reproduce in any speaker design. This range comprises so much of the soul of the music we love, and the sad truth is that this midrange cone is incapable of faithfully reproducing music in this critical band.
The video shows too that the paper cone is in complete chaos at 5kHz, the middle of the “presence region” of the frequency spectrum. The presence region is above the midrange but well within the overlap region where the midrange driver transitions to a tweeter. This range has a distinct effect on vocals and instruments, as recording and mixing engineers are very aware of.
The types of gross distortions demonstrated in this video are audible not only as a loss of resolution, but also as noise and dynamic compression. When the driver cone motion becomes chaotic, sounds are still produced in the areas of the cone that are in “breakup mode.” But those sounds aren’t related to the musical signal. Sound you can hear that bears no relation to the signal is pure distortion. Or, in a word, just noise. And the paper midrange in the video is producing a LOT of it.
The paper cone distortions demonstrated in the video also soften transient impact and blunt dynamic peaks. Loudspeakers simply cannot deliver full dynamic range when large portions of the driver cones are not moving with the signal in pistonic fashion. The orchestra can no longer play at full power when the loudspeaker’s driver cones are in “break-up mode” and the cone’s motion is chaotic.
Speaker distortions such as these are often explained away as sins of omission. In fact the “lossy” nature of these distortions might smear enough musical information to hide flaws in other components in an audio system. While speakers with paper cones exhibit compromised dynamics, they can often be played VERY loud which fools less experienced listeners into believing they are hearing real dynamic range. But all distortion factors increase as the volume goes up, especially in power amplifiers. There is no free lunch.
These may be acceptable compromises in entry level or mid-fi systems. At Vandersteen Audio, we see no reason on earth to accept compromises like these in statement loudspeakers at high prices.
Vandersteen Audio customers have always demanded more and so has Richard Vandersteen. Richard spent a decade on the R&D that led to Vandersteen’s patented Perfect-Piston carbon-fiber/balsa core driver cones, shown in the video to be truly pistonic and unflappable.
Vandersteen’s Perfect-Piston driver cones are handmade in Vandersteen’s California factory. They debuted in the Model Seven in 2009 and are still used in the Model Seven Mk II, Vandersteen’s current flagship. Driver cones descended directly from these amazing designs are also featured in Vandersteen’s Model 5A Carbon (Carbon Midrange and Tweeter), Quatro Wood CT (Carbon Tweeter), and Treo CT loudspeakers. For home theater enthusiasts, CT versions of the Vandersteen’s VCC-5 center channel and VSM surrounds are coming soon.
The video here dramatically demonstrates the distortion-free pistonic performance of these incredible drivers over a wide range of frequencies. It is not a coincidence that the Model Seven and Seven Mk II are on an unprecedented tear of great press and “Best of Show” accolades that is nearing a decade in duration. Other brands merely claim state-of-the-art components and performance. Vandersteen Audio proves it."
https://www.vandersteen.com/news/the-truth-about-pistonic-driver-cones
This is another interesting video showing the effect at low frequency and high amplitudes...
Here is an interesting post from Paul DiComo (RIP 2021) on the Polk Audio Forum about cone materials. One of the two key things he pointed out is that composite materials can offset undesirable characteristics of just one kind (whether paper, plastic, etc.), and that plastic-based cones can be molded to have varying thicknesses from center to the edge (if the designer deems it of value) vs. paper that cannot. But read for yourself...
https://forum.polkaudio.com/discussion/512/paper-vs-plastic-drivers
Paul DiComo Polkosaurus Rex Posts: 272
September 2001 edited September 2001
First, for those who don't know me, I've been at Polk for over 18 years and have had more Polk speakers in my home than I could ever remember.
The paper-based cones from days past were revolutionary in their day. They were among the frst designs to use a composite structure to reduce cone resonance for flatter response. The principle is that if you combine materials with dissimilar resonance characteristics they tend to cancel each other's modal breakup modes. Think of a sheet of metal and a sheet of plastic. Alone the metal sheet "rings" when struck. The plastic sheet doesn't ring but has low frequency resonance and lacks the stiffness to be an efficient piston. But combine them together and you now get the best of both worlds. The plastic damps the ringing of the metal and the metal stiffens the plastic. The net result when you do that sort of thins in a speaker cone is flatter frequency response and reduced distortion.
The old paper cones were treated with one polymer material that stiffened the paper and a second (the sticky shiny stuff) damped the surface (acted like the soft plastic sheet in the analogy above).
In the new cones the different materials are combined together in the cone. There are both damping and stiffening elements. Yes, it is true that the new composite plastic cones are easier to produce BUT have innumerable advantages over the treated paper cones. Here are two:
1. The composite plastic cones are injection molded. That means we can (and do) vary the thickness of the cone across its cross section. The cone is thicker near the voice coil and thinner at the circumference (is that spelled right?). That makes it better in ways I am too lazy to explain. Trust me it is better.
2. The new cone is lighter, yielding higher efficiency and better transient response.
So what does this all mean in terms of sound? IMHO (well maybe not Humble), the new drivers have MUCH better detail and sound far more natural. It is an objective fact that they produce a flatter and broader frequency response with lower distortion than the old drivers.
I have a couple of pairs of older Polks with paper cones (including SDA-CRS+) and as much as love them as I do for some of their other qualities, I must recognize their weaknesses. The new models I have had at home sound more life-like with far better articulation and detail. The old models sound a bit "congested" and "thick" in the midrange.
As for the change in look to the tri-laminate tweeter - we changed the substrate material to get a little better performance and the metal coatings look a little different on the new material. There always has been noticeable color variation in the metal coatings from batch to batch but that makes absolutely no difference in measurable or subjective performance - just color.
BUT all the above having been said - you can't judge a book by its cover and you can't judge a speaker entirely by the materials used in its drivers. I have heard good very sounding paper cones and bad. I have heard LOTS of very bad sounding speakers that used exotic cone materials. A hack can screw up anything and a good designer can get the most out of the materials he has to work with.
Use your ears to judge. Use the standard of live acoustic music to set a proper frame of reference.
https://forum.polkaudio.com/discussion/512/paper-vs-plastic-drivers
Paul DiComo Polkosaurus Rex Posts: 272
September 2001 edited September 2001
First, for those who don't know me, I've been at Polk for over 18 years and have had more Polk speakers in my home than I could ever remember.
The paper-based cones from days past were revolutionary in their day. They were among the frst designs to use a composite structure to reduce cone resonance for flatter response. The principle is that if you combine materials with dissimilar resonance characteristics they tend to cancel each other's modal breakup modes. Think of a sheet of metal and a sheet of plastic. Alone the metal sheet "rings" when struck. The plastic sheet doesn't ring but has low frequency resonance and lacks the stiffness to be an efficient piston. But combine them together and you now get the best of both worlds. The plastic damps the ringing of the metal and the metal stiffens the plastic. The net result when you do that sort of thins in a speaker cone is flatter frequency response and reduced distortion.
The old paper cones were treated with one polymer material that stiffened the paper and a second (the sticky shiny stuff) damped the surface (acted like the soft plastic sheet in the analogy above).
In the new cones the different materials are combined together in the cone. There are both damping and stiffening elements. Yes, it is true that the new composite plastic cones are easier to produce BUT have innumerable advantages over the treated paper cones. Here are two:
1. The composite plastic cones are injection molded. That means we can (and do) vary the thickness of the cone across its cross section. The cone is thicker near the voice coil and thinner at the circumference (is that spelled right?). That makes it better in ways I am too lazy to explain. Trust me it is better.
2. The new cone is lighter, yielding higher efficiency and better transient response.
So what does this all mean in terms of sound? IMHO (well maybe not Humble), the new drivers have MUCH better detail and sound far more natural. It is an objective fact that they produce a flatter and broader frequency response with lower distortion than the old drivers.
I have a couple of pairs of older Polks with paper cones (including SDA-CRS+) and as much as love them as I do for some of their other qualities, I must recognize their weaknesses. The new models I have had at home sound more life-like with far better articulation and detail. The old models sound a bit "congested" and "thick" in the midrange.
As for the change in look to the tri-laminate tweeter - we changed the substrate material to get a little better performance and the metal coatings look a little different on the new material. There always has been noticeable color variation in the metal coatings from batch to batch but that makes absolutely no difference in measurable or subjective performance - just color.
BUT all the above having been said - you can't judge a book by its cover and you can't judge a speaker entirely by the materials used in its drivers. I have heard good very sounding paper cones and bad. I have heard LOTS of very bad sounding speakers that used exotic cone materials. A hack can screw up anything and a good designer can get the most out of the materials he has to work with.
Use your ears to judge. Use the standard of live acoustic music to set a proper frame of reference.
Another good video IMO on cones and materials, and impact on characteristics, from the speaker engineer at PS Audio...
As far as I understand, the problem is not about angle. It's about interference (comb filtering) between the two drivers in the frequency range where they cross over. So, if your crossover point is 2 kHz, the distance between the drivers should be close enough so that they are acoustically co-located (behave as one source rather than two) at and around that frequency. I don't know if it's one wavelength or half a wavelength. At 2K, wavelength is 6.7 inches.
Most of the work done waggling our eardrums comes from reflections not the direct sound. The brain pays more attention to the initial louder direct sound but the reflections are heard and logged. With a wide apart tweeter and midrange one can arrange for the direct sound to be fine but the reflections will have spectra with strong and varying peaks and dips. This is clearly audible. So long as one uses decent drivers of adequate size operating over a reasonable frequency passband of about a decade the main speakers (e.g. a 3-4 way with a 12"(ish) woofer and a well designed active crossover) can reproduce the direct sound with a high level of fidelity to the extent it has a neutral contribution to the perceived sound quality. What dominates the perceived sound quality are the reflections following from the off-axis response.