I was just re reading this interesting thread and would like to point out that when someone specifies a driver size, say 6.5 inches, that is not the size of the cone which is producing the wavelength. Drivers are specified by the basket size. Since all drivers are built a little differently, you have to find the true diameter of the radiating area and then simply use the speed of sound which is
13,514.17
inches per second at sea level.
So you'll find that, say, a driver is listed at being 6.5 inches, the radiating area will be around 137cm2 and the actual diameter of the cone is 5.19 inches. At sea level it starts beaming at 13,514.17/5.19=2600 Hz which is smack dab at the place where most dome tweeters have to be crossed over.
So that's why there are so many "6.5 inch" woofers out there. They just make it to the glory point with a 1 inch dome tweeter.
Which is not to say that there are some very pleasing speakers that have been made using larger midranges.
I listened to a 3 way horn hybrid speaker with a 15 inch woofer crossed over at 800 hz for 15 years until the woofer rotted away and I had to sell the thing for parts. Lots of ways to skin a cat.
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Phusis, we agree to disagree (which is just fine with me). :-)
I'm happy that you subscribe to some Nathan Lewis' opinion on this matter but it's just his opinion & I have no idea what his exposure & knowledge of audio is? |
Bombaywalla -- They take an interesting approach, Brodmann Acoustics, and seem fairly priced. Never heard them. One of the more memorable sonic demoes I've had came from the Peak Consult Kepheus at their home facility in Denmark. The twin Audio Technology 5" midrange units presented some of the most natural (and dynamic) mids I've encountered - certainly coming from cones - just as they are beautiful and coherent sounding overall. Although steeply(!) priced it's beyond me why these handcrafted speakers aren't referred to more often, if at all in the "audiophile arena;" it can't be the high price, for that alone seems to have its drawing power all by itself. One suspects that what sounds natural simply isn't interesting enough.. But in the end, to my ears, nothing trumps the ease, tone, clarity and relaxed power from a well-implemented waveguide/horn, preferably conical variants, and larger cones. This sums it up nicely: I am amazed today that 99% of all "audiophile" speakers are the basic "monkey coffin" cones and domes in a box that have defined the industry for the last forty years. This is fine for general consumer stuff, but, no matter what the price, you can only get so much out of a 5" cone midrange and a 1" dome tweeter, and it isn't enough, in my opinion, for even modest ambitions. It's just the physical nature of the elements involved. http://www.newworldeconomics.com/archives/2013/111713.html"It's just the physical nature of the elements involved" - indeed... |
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Phy hp, from France makes a very good 30 cm speaker. Makes magical midrange |
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Bombaywalla -- I have a fair bit of world-wide listening experience & have listened to a lot of speakers (& a lot of electronics) yet to but yet to have a positive experience of a 12" midrange playing midrange. If you look at my systems I do own a Tannoy DMT10Mk2 which has a 10" playing midrange all the way up to 1.4KHz. It sounds good for the most part & is just fine for the use that I've put it to but when I had a time-coherent speaker with a 4.5-5" Eton midrange, the Tannoy was nowhere near that quality. Having not heard the Tannoy model you own I still believe what you hear could be categorized under 'preference' with regard to certain aspects of sound. Take 6moons review of the Austrain WLM Diva Monitor speakers (for a hopeful illumination): (excerpts) 10-inch paper cones with hard cloth surrounds simply sound different than 5-inch Beryllium or ceramic cones that are hung off loose butyl rubber. The former are more natural, relaxed and full to my ears. In turn, they're not as overtly 'resolved'. The sharpness and leanness often associated with accuracy is missing.
...
It's a speaker that will tweak certain people because it lacks what they consider prerequisites for a hi-end worthy design - narrow baffles, small midrange drivers, exotic diaphragms, famous tweeters. WLM gets by with apparently lesser ingredients. Still and to my ears, the end result is a more inviting, tastier dish. What that really says about current high-end hifi sensibilities you may ponder yourself in some spare time.
...
As our own Jeff Day reminds us, there's a music lover's perspective which deviates from the studio monitor credo of 'warts'n'all'. Music lovers first and foremost insist on an emotional connection with the music. Secondly, they insist -- very sensibly if you ask me -- that all of their music and not just a very narrow selection thereof be enjoyable. The Diva Monitor conforms perfectly to this omnivorous demand. It's a tone monster. That makes it a fabulous addition to the retro/vintage sector of loudspeaker design where large paper cones with pleated cloth surrounds remain en vogue. Those counter the over-articulated 'starving super model' ideal that's pursued to excess elsewhere. It returns us to the earthy curves of a Sophia Loren, the power and brio of Classic Rock and the soulful tone of a Mesa Boogie. http://www.6moons.com/audioreviews/wlm/divamonitor_4.htmlTime coherency of definately an important factor in sound reproduction, but it's a singular aspect attainable in many forms with many variables. The WLM Diva's are one way to get there, and going by the floorstander version of the Diva's it's a sonic imprinting I enjoyed immensely. In other incarnations though, despite being time coherent speakers, it could be an entirely different matter - to my ears at least. |
Phusis
My impressions is that it's not without audible importance how a given amount of air is moved; either "gently" via a larger area, or "forcibly" through a smaller ditto. My preference - if it is indeed explained fundamentally through this aspect - is for the former, and this goes for the whole frequency spectrum. And I agree with you. The larger the radiating surface, the smaller the excursion required to achieve the same SPL. A 5" midrange has about 19.5 sq. in. of radiating surface; The Magnepan 1.7 has 456, or 23 times as much. The Magnepan's microscopic excursion has a profound effect on inertial artifacts--the mechanics of acceleration, stopping, ringing, and reversing. It results in a relaxed, natural presentation. Note the expensive and herculean efforts to reduce this in a pistonic driver: the TAD coincident drivers are made of vapor deposited beryllium--brittle, fragile, but incredibly light to minimize inertial effects.
Moreover, the number of point sources (convering the same frequency span) is also a factor. With regards to bass (and the rest of the sprectrum), generally, I'd rather have one unit covering what two or more units equaling the same radiation are can muster.
I agree here, too The miraculous thing about the Maggie 1.7 is that it speaks in such a single, coherent voice for just $2K/pair. The TADs also do it with a 6.5" coincident driver that covers 8 octaves. Its point source would have an imaging advantage over the Maggies' line source, and the upper models have more bass reach, but at a significant price difference. |
Johnnyb53 -- ...
Finally, the name of the game isn't just radiating area; it's air displacement. A 4.5" driver has a radiating surface of 15 sq. inches. My Mag 1.7s have a radiating surface of 456 sq. inches. Yet, a premium 4.5" midrange might have a maximum excursion of .2", which amounts to around 3 cu. in. of displacement. My big panel, if its excursion is .01" (I'm guessing here, but it's probably in the ballpark), displaces about 5 cu. in. of air even though it's spread over a wider area. So two of those 4.5" midranges would displace about the same amount of air at full excursion. This is an interesting aspect. My impressions is that it's not without audible importance how a given amount of air is moved; either "gently" via a larger area, or "forcibly" through a smaller ditto. My preference - if it is indeed explained fundamentally through this aspect - is for the former, and this goes for the whole frequency spectrum. Moreover, the number of point sources (convering the same frequency span) is also a factor. With regards to bass (and the rest of the sprectrum), generally, I'd rather have one unit covering what two or more units equaling the same radiation are can muster. |
08-25-14: Psag
TAD concentrics use a 6.5" midrange.
Point? _ |
TAD concentrics use a 6.5" midrange. |
Love the Maggies! Just wish they were more efficient. |
And Magneplanar X.7 series--1,7, 3.7(i), and 20.7--have sort of blown past the stereotypycal limitations of Maggie speakers. My 1.7s are dynamic, coherent, and can play loud and clean on 100 wpc (200 into thei 4 ohms) in a vaulted ceiling open architecture living room. The X.7 series are the first Maggies not to have been designed by founder Jim WIney. They were designed by his son, who apparently successfully addressed the chronic complaints about the previous iterations. |
The Martin-Logan Summit X's are rated 91 dB/2.83 volts/meter, and can handle 200-600WPC. The CLX's; 90dB/2.83 volts/meter, and can handle 20-450WPC. Either should be capable of satisfying most SPL cravings, quite well. I've always said, "size matters!" |
I think the planar route is the way to go.
I'll have to wait for Martin-Logan to vapor deposit
diamond onto their panels so they can play at higher SPLs
without breaking up.
Peace |
08-25-14: Dweller
Thanks guys for trying to teach an old dog new tricks.
I'm looking for a way to get a more life-like listening experience.
You're trying to tell me why I can't have it.
Nobody said you can't have midrange coming from a large radiating surface. Some of us were pointing out that as the wavelength approaches and exceeds the diameter of the driver, the driver starts beaming and continues from there on up. When you have a range of beaming frequencies, it may sound OK on-axis, but those beaming frequencies go missing in the overall in-room balance. This is expressed as in-room power response. A couple of the exceptions cited in this thread have reasons to work. We established that the 6.5" midrange of the Hyperion hps-938 has an active dustcap that funcions as a small-diameter midrange to offset the beaming of the 6.5" section between 2K and the crossover at 3K. Furthermore, I read up on your Dvoraks with their MTM arrangement with 8" midranges, and it turns out that this is a dipole design. That makes a world of difference, because even though the 8" midranges would be beaming at 1700 Hz, since they're also firing backward and hitting the wall behind, this compensates for the beaming by adding to the power balance in that frequency range. It's also how panel speakers, which tend to have narrow dispersion, have good overall in-room power response, because the backwave hitting the back wall compensates for the narrow dispersion to the front. As for getting a large radiating surface for the midrange, there are several approaches. First is panel speakers. I have Magneplanar 1.7s. They have approx. 456 sq. in. of bass/midrange radiating surface--radiating both front and back. They are transparent and (with good setup), well-focused. Second, you can get a speaker with dual or multiple midranges such as your Dvoraks had. If you have 8" midranges it helps if they're mounted in an open baffle as your Dvoraks were. Third, you can get a large diameter full range driver which has compensations for the beaming aspect. I recently visited an audio buddy whose main speakers are Audio Nirvana 15" full-range drivers. These raw drivers are $500-$1000/pair depending on magnet type. His are mounted in large ported enclosures--2'x2'x4'tall, with three big ports to the front. Despite the large diameter, these speakers had excellent power response. I detected no beaming when listening off-axis, and walking around the room the overall tonal balance was excellent with no noticeable suckout. How'd they do this? The speaker has both a whizzer cone and a copper phase plug. This is exactly what whizzer cones are for--they provide a small diameter cone to keep higher frequencies from beaming. The phase plug also gives a focused surface for these frequencies to bounce off of, futher improving dispersion of the highest frequencies. He is considering remounting the speakers in an open baffle (like your Dvoraks), however, to open up the sound a bit and eliminate cabinet resonances. Yet another way to increase radiating surface is with multiple dynamic drivers, with two or more 4-5" midranges. Axiom makes some examples of this including their M100, which has three 6.5" woofers, dual 5.25" midranges plus dual 1" tweeters. They also make an omnidirectional speaker with the same front array plus two more 1" tweeters and two 5.25" midranges firing to the rear. These speakers are engineered by Andrew Welker, who designed those great omnidirectional speakers for Mirage before Klipsch shut them down. Bryston's new line of speakers show a decided dependence on Axiom for their design philosophy, including dual mids and tweeters for lower distortion and greater dynamic range. Yet another alternative is a tall column speaker with a dozen or so midranges and even more tweeters in a line array. Finally, the name of the game isn't just radiating area; it's air displacement. A 4.5" driver has a radiating surface of 15 sq. inches. My Mag 1.7s have a radiating surface of 456 sq. inches. Yet, a premium 4.5" midrange might have a maximum excursion of .2", which amounts to around 3 cu. in. of displacement. My big panel, if its excursion is .01" (I'm guessing here, but it's probably in the ballpark), displaces about 5 cu. in. of air even though it's spread over a wider area. So two of those 4.5" midranges would displace about the same amount of air at full excursion. |
08-25-14: Dweller
Thanks guys for trying to teach an old dog new tricks.
I'm looking for a way to get a more life-like listening experience.
You're trying to tell me why I can't have it.
it appears to me that you have, very broadly speaking, 2 choices: a speaker with large diameter midranges (like 10" or 12") that are crossed over in the low midrange region & a speaker with a more conventional 4-5" midrange driver crossed over at the upper mid-bass The large diameter driver speakers seem to be made of proprietary drivers - from Altec Lansing, JBL, Tannoy, RCA, Westinghouse & your former Audio Artistry Dvorak. If there are any other names other members can please chime in. And, these drivers, being proprietary are not available to the general public for other speaker manuf to make speakers. So, if you are convinced that a large midrange is what you want you'll have to go with these limited speaker brands. OTOH, you can have a perfectly fantastic realistic/life-like listening experience with a 4-5" midrange if you get yourself a time-coherent speaker. This is a really -l-o-n-g- discussion & I will NOT go into it here. Please read the "Sloped Baffle" thread (which has some 220 posts) here in the Speaker forum. http://forum.audiogon.com/cgi-bin/fr.pl?cspkr&1403209611&&&/Sloped-baffleConcentrate on Roy Johnson's posts as to why time-coherence is important in music playback & how it maintains the correct information in the music signal & why it delivers a realistic/life-like music experience. There are a few speaker manuf making these time-coherent speakers so unfortunately once again a limited choice. That's the way it is - most speaker manuf do not understand the physics to make a time-coherent speaker - they think that time-coherence is one of many parameters that can be traded-off with some other speaker design parameter. It is not! Either a speaker is time-coherent from the get-go or it is not. The speaker manuf needs to select time-coherence as the design paradigm & then solve all the speaker manuf issues within the time-coherence paradigm. It is my belief (becoming firmer & firmer as I listen more to various systems & talk to others & their disappointing listening experiences) that large amounts of phase distortion from the speaker is what's destroying people's listening pleasure & causing people to make remarks like I'm looking for a way to get a more life-like listening experience. If you had a time-coherent speaker you wouldn't be saying this. Of course, not everyone participating in this thread has a time-coherent speaker & not everyone in this thread is complaining of a lack of realistic experience. I.E. many people with NON time-coherent speakers are very happy. I'm finding out that today a lot more people are dissatisfied compared to the year 2002/2003 when I was 1st exposed to time-coherence. So, it's good to see that more people are realizing that the life-like experience is diminishing. This awakening is good - hopefully it'll make the speaker manuf change their design philosophies.... |
but while I appreciate your addressing "physics" I believe you adhere to them in a rather non-flexible fashion that cares more about numbers than, it would seem, actual listening impressions - or at least you're without the positive experience of a 12" playing midrange above 1kHz, in which case I respect. I just don't share the same experience. I have a fair bit of world-wide listening experience & have listened to a lot of speakers (& a lot of electronics) yet to but yet to have a positive experience of a 12" midrange playing midrange. If you look at my systems I do own a Tannoy DMT10Mk2 which has a 10" playing midrange all the way up to 1.4KHz. It sounds good for the most part & is just fine for the use that I've put it to but when I had a time-coherent speaker with a 4.5-5" Eton midrange, the Tannoy was nowhere near that quality. Johnnyb53, thanks much for the clarifications. |
Bombaywalla -- To reiterate from an earlier response of yours (to the OP): The Tannoy Kingdom Royal has NO MIDRANGE driver contrary to what you seemed to allude to.
Their new HF compression driver tweeter is doing all the midrange.
Like you seemed to indicate - Tannoy is not foolish & they wouldn't put a 12" midrange! The 12" unit does upper bass to 700Hz & the lower bass unit does the bottom-most octave. Well, the Tannoy Kingdom Royal has got a midrange driver (sorely needed to play midrange) - that is, not only one but two of them: the 12" unit for the lower mids, and the compression driver for the rest above 700Hz. In your reply to me: no dispute here Phusis. I was not stating otherwise. Merely stating that the bulk of the midrange freq is handled by their new tweeter. Yes, freq below 700Hz is handled by the 12" mid driver which seems to be more suited to the lower freq. Tannoy smart as they are did not try to do any more midrange with the 12" driver - that was my point. Given the choice of two well-implemented speaker systems I'd not necessarily choose the one where a compression handles midrange duties from 700Hz up (which, in effect, would likely be a 3-way setup, or more) compared to a 12" unit handling the mids up to 1.3kHz (which, crossed over to a compression driver, could be a 2-way ditto). You seem fairly adamant in claiming that a 12" can't do midrange much above 700Hz; I say it can - and certainly the beaming limit for a unit this size (with an effective cone diameter of ~10") is not yet reached, even at 1kHz. In the case of the Tannoy's mentioned I do believe they made the right choice crossing over the 12" unit no higher than 700Hz, also being that the compression driver here is augmented by a "supertweeter." You continue: good advice Phusis. I keep an open mind while keeping Physics in my mind at the same time. Hopefully you do the same....
Timlub tried to explain some of the physics to you but it went over your head. I tried too in my very 1st post & it looks like that went over your head as well.
Well, you can take a horse to water but you cant make it drink... I find the writings of Mr. Timlub enlightening, indeed there's something to learn here, but while I appreciate your addressing "physics" I believe you adhere to them in a rather non-flexible fashion that cares more about numbers than, it would seem, actual listening impressions - or at least you're without the positive experience of a 12" playing midrange above 1kHz, in which case I respect. I just don't share the same experience. Something went over my head? I don't think so, but while I'm glad to learn I have no problem going contrary to stated physics if my ears tell me otherwise, and in my case and with my speakers there's no seeming dissonance between what I hear and what physics should imply. |
Thanks guys for trying to teach an old dog new tricks.
I'm looking for a way to get a more life-like listening experience.
You're trying to tell me why I can't have it. |
johnnyb53, I get it. the point is do the likes of you & Dweller get it?
Once again: Tannoy smart as they are did not try to do any more midrange with the 12" driver - that was my point. Hopefully you got that?
thanks. That was sloppy editing on my part. I was totally agreeing with you. Where I said "apparently you refuse to catch on..." I was addressing Dweller, not you. I was trying to corroborate your assertion about the 700 Hz crossover, that it's well below the frequency where a 12" driver would start beaming, and that the Tannoy 12" driver functions more as a woofer than as a midrange. I don't usually get that jumbled up in pronouns and their antecedants. |
To clarify: 700Hz er certainly part of the midrange (indeed the lower part of the central mids), and voices typically contain a lot of energy even lower in the frequency spectrum. no dispute here Phusis. I was not stating otherwise. Merely stating that the bulk of the midrange freq is handled by their new tweeter. Yes, freq below 700Hz is handled by the 12" mid driver which seems to be more suited to the lower freq. Tannoy smart as they are did not try to do any more midrange with the 12" driver - that was my point. What's to learn is oftentimes to unlearn, keep an open mind, and be willing to go against accepted (read: rigid) norms. good advice Phusis. I keep an open mind while keeping Physics in my mind at the same time. Hopefully you do the same.... Timlub tried to explain some of the physics to you but it went over your head. I tried too in my very 1st post & it looks like that went over your head as well. Well, you can take a horse to water but you cant make it drink... 700 Hz wavelength is over 19" long, so a 12" driver wouldn't even be close to beaming. Tannoy knows what they're doing, but apparently you refuse to catch on, even with multiple corroborating explanations. johnnyb53, I get it. the point is do the likes of you & Dweller get it? Once again: Tannoy smart as they are did not try to do any more midrange with the 12" driver - that was my point. Hopefully you got that? thanks. |
The Tannoy Kingdom Royal has NO MIDRANGE driver contrary to what you seemed to allude to.
Their new HF compression driver tweeter is doing all the midrange.
Like you seemed to indicate - Tannoy is not foolish & they wouldn't put a 12" midrange! The 12" unit does upper bass to 700Hz & the lower bass unit does the bottom-most octave. 700 Hz wavelength is over 19" long, so a 12" driver wouldn't even be close to beaming. Tannoy knows what they're doing, but apparently you refuse to catch on, even with multiple corroborating explanations. Fool that I am, I'll give it one more go: In the '70s I owned a pair of Altec-Lansing 9845a professional studio monitors. They had the typical Voice of the Theater (VOTT) components--15" woofer and compression-driven aluminum horn. Around that same time I worked at a stereo store where we carried Altec, including some home versions of the VOTT. But they sounded significantly different. My pro audio VOTT crossed over at 500 Hz, which is a 27" wavelength and well outside the beaming frequency (900 Hz) of a 15" wavelength. The home version, however, crossed over at 1200 Hz, which is an 11" wavelength. That means that *that* 15" woofer was beaming from 900 Hz on up past the 1200 Hz crossover frequency. And you could hear the difference--a kind of "cupped hands" coloration in the crossover frequency area. I think the difference in crossover frequency was due to the pro version having a better, more expensive and rugged compression driver that could play lower. The cheaper home version crossed over at 1200 Hz for power handling. These days, no one in their right mind would cross over a 15" woofer that high without a wave guide, whizzer cone, or at least a phase plug. Unaware at the time about beaming, dispersion, and in-room power response, we typically figured that the horn was making the music sound horn-like. Yet my pro monitors had no such coloration (in fact, they kicked ass!). I also found that this suckout wasn't very noticeable when playing jazz combos and larger scale instrumental music, but was immediately noticeable on solo voice. From that point on--as much as I like instrumental music--I can't consider a speaker without hearing what it does with vocals. So there's a little more anecdotal evidence for the impact of beaming on an inappropriate crossover point. |
Bombaywalla --
What's to learn, exactly - that 12" units can't do midrange? To clarify: 700Hz er certainly part of the midrange (indeed the lower part of the central mids), and voices typically contain a lot of energy even lower in the frequency spectrum. Upper bass sits below 300Hz, not at a high 700Hz.
12" units can do wonderful midrange, but you wouldn't expect an 88-90dB, fs 20-30Hz hifi bass ditto to do this job; it's supposed, or certainly restricted to do bass only. There are other 12" units to come by with higher efficiency, higher fs, and lighter cone movements, and there's good reason to seek out their qualities in the mids department as opposed to the smaller diameter alternatives - depending of course on the design they are to be implemented.
What's to learn is oftentimes to unlearn, keep an open mind, and be willing to go against accepted (read: rigid) norms. |
08-24-14: Dweller
Hey! Tannoy! You've only been making speakers since 1926 so take some more lessons because somebody on this web-site thinks you and I are "confused".
Stop making your $55,000 Kingdom Royal until you get straightened out and start using 5" midrange drivers!
(dang this is fun!)... Dweller, you asked the question & when info has been given to you, you don't want to learn! There seems to be disbelief on your part. Why ask the question if you don't want to learn??? Just curious to know... This info from 2 websites: tannoyspeakers.com & tannoy.com (it looks like you haven't spent much time reading it..) The first Dual Concentric loudspeaker, designated the monitor black, and designed by Tannoy's chief engineer at the time, Ronnie H. Rackham, appeared at the London Radio Show in 1947. It was in 1926 when Guy R. Fountain (GRF) perfected a new type of electric rectifier with the aim of designing a charger more suitable for use in the home. I really don't know when Tannoy built it's 1st speaker but it wasn't in 1926. the following info is about the Tannoy Kingdom Royal loudspeaker from Tannoy's website. Read a little about the Kingdom Royal's drive unit - scroll to the middle of that webpage & look under "Drive Unit": The crossover to the DCs high frequency unit occurs at an exceptionally low 700Hz to ensure the majority of the vocal region is handled by the new tweeter. The Tannoy Kingdom Royal has NO MIDRANGE driver contrary to what you seemed to allude to. Their new HF compression driver tweeter is doing all the midrange. Like you seemed to indicate - Tannoy is not foolish & they wouldn't put a 12" midrange! The 12" unit does upper bass to 700Hz & the lower bass unit does the bottom-most octave. You know, Shakey might have a very valid point..... |
Hey! Tannoy! You've only been making speakers since 1926 so take some more lessons because somebody on this web-site thinks you and I are "confused".
Stop making your $55,000 Kingdom Royal until you get straightened out and start using 5" midrange drivers!
(dang this is fun!)... |
Johnyb53, unfortunately Hyperion went bankrupt since design is only small part of success. Now, I feel uneasy about spare parts or service. |
Kijanki: I just checked out the 6Moons in-depth review (from 10 yrs ago) of the Hyperion hps-938. The midrange unit addresses this dispersion challenge in its design. Notice that the Hyperion midrange has a large, flat dustcap. It's not a typical dustcap, however. Hyperion called this the SVF--Synchro Vibrate Flattop. This dustcap floats independent of the main diaphragm and is connected directly to the voice coil. What this does is provide a midrange-within-a-midrange of smaller diameter to ensure wider dispersion of high frequencies that would beam at 6-1/2" but not at 3" (or whatever diameter this floating dustcap is). That's a pretty ingenious solution to have it both ways--larger diameter for more radiating surface and deeper reach while keeping dispersion consistent as frequencies rise toward that rather high 3K crossover point. That's what whizzer cones and phase plugs are used for in many fullrange drivers (e.g. Fostex and Audio Nirvana). But Hyperion's flattop dust cap strikes me as a more ingenious and precise way to achieve that. |
Kijanki, yes larger diameter voice coils are definitely desirable from a thermal standpoint, all else being equal. Ferrofluid helps as well, assuming it's a good heat conductor, which it probably is. On the other hand I don't recall seeing any prosound company using ferrofluid, so it may have downsides when subjected to high temperatures over time.
I can't comment on the unorthodox suspension system of the cone drivers in the Hyperion; I don't know enough about suspension systems.
Duke |
Lewinskih01, I have no idea. Hyperion went bankrupt (poor marketing,
poor dealer base) without any parts sale. I'm not sure why they decided
upon such large midrange driver but I suspect they wanted to reduce
membrane excursion making it more linear. 3kHz xover was probably
selected to stay away from the tweeter's resonance that is around 1.5kHz.
If this xover is single pole 6dB per octave then tweeter helps keeping
dispersion around 2.5-3kHz, as Johnyb53 stated. It is possible to
improve linearity at large excursions by using underhung, instead of
common overhang motor. It is rare, likely because of the increased cost
(large magnet). I've seen this only in Acoustic Zen woofers or Morel
Supreme tweeters. In underhung motor coil is very narrow while
magnetic gap is very wide. Coil is all the time inside opposite to
overhang design where coil is long being mostly outside of very narrow
magnetic gap. |
Johnk..... I betcha that wherever that baby beams it smacks you in the head.
Really though, we're off of the ops topic, but what we have been discussing about cone drivers is the where the driver starts losing dispersion characteristics. I kinda eluted to that in my snide question. Once the width of dispersion starts decreasing, we hear the beaming effect... Yes, I'm sure that is known, but just wanted to clarify for others.
There are ways around the beaming effect.. Ohm fires off the back side of their cone... Bose uses direct reflecting technology... both have their own issues. Mainly, any decent designer will properly work around the individual drivers problems do a fair degree. There are trade off on any speaker... period. Frequency extention capabilities, driver peaks or dips, excursion limits, Impedance/phase dips, etc, etc, etc. |
Have a loudspeaker that I'm working on with 14ft long horn 43x62in bell 4in compression driver used as a mid range. |
As well as bombaywalla tried to explain it, I think dweller is still confused.
Shakey |
Kijanki,
Do you know who makes good ferrofluid suspended drivers like the ones in you Hyperions - or better yet, the ones found on your speakers? I'd like to learn more for a DIY project.
----
FWIW, back in the "slopped baffle" thread Roy Johnson from Green Mountain Audio made several points about driver size and selection. He mentioned he used a 4.5" midrange driver for his Calypso as it was designed to work in living rooms and audio rooms, but he used larger drivers when designing speakers for vary large rooms. So I wonder how much of a concern is beaming for him, as it would seem the detrimental effect of beaming would be more notorious the larger the room.
Good thread! |
The largest cone midrange I can find is in the Tannoy "Kingdome Royal" speaker.
It uses a "12in Dual ConcentricTM drive unit" with a tweeter in its center.
Now we're talking (where did I put that Tool CD?"! |
Duke, midrange drivers in my speakers use ferrofluid suspension instead of spiderweb (to increase speed by lowering overall mass). Coils are oversized connected to flat ring that holds membrane (instead of dust cap). http://www.enjoythemusic.com/superioraudio/equipment/1104/hyperionhps938.htmI assume that oversized coil in ferrofluid has low thermal compression. I'm only worrying that ferrofluid will dry out one day. |
Of course every designer has different priorities, but one of Siegfried Linkwitz's top priorities in the Dvorak was radiation pattern control. His target radiation pattern called for fairly large diameter midrange cones.
Impact and dynamics are preserved when the loudspeaker system doesn't impose audible thermal or mechanical compression on the signal. Mechanical compression of midrange drivers shouldn't be an issue in a well-designed system, as the crossover should protect them from reaching their linear excursion limits.
Minimizing thermal compression is not necessarily a function of cone diameter; it is more a function of efficiency and the thermal capacities of the motor/voice coil assembly. Generally, the more powerful the motor and larger the voice coil, the less thermal compression. Obviously increasing the number of drivers reduces the thermal compression at a given SPL. (Thermal compression is a rather complicated subject and detailing it is beyond the scope of this post, so I'm painting with a broad brush here.)
I'm very much a fan of Linkwitz's work, and his designs combine excellent performance in many areas. In my opinion, radiation pattern control where his designs really excel.
Duke
dealer/manufacturer |
Some of the more important reasons why we rarely see midrange drivers above, or even approach 7-8" in the typical regime of "hifi" speakers seem dictated by the use of direct radiating dome tweeters and their lack of <2kHz handling, as well as a common demand for midrange drivers to co-act as low fs bass units in 2-way systems, where 6.5" driver would see limitations in speed and agility starting already in the upper bass and lower mids. Even "dedicated," smaller midrange drivers (up to ~5") in 3-ways systems seem to emulate almost the design of the more typical hifi bass drivers, certainly going by their efficiency and overall specs, making you wonder what is gained by the smaller diaphragm diameter when this again limits the preservation of energy (and not least its nature) that comes through added, sheer displacement area. My own speakers sport a 12" bass/mid driver (crossed at ~1.3kHz to a 12" compression driver-driven OSWG waveguide) with a relatively lightweight paper cone and moderate sensitivity of about 94dB, and though this sits close to the beaming wavelength of the effective cone diameter the audible outcome is nonetheless more dynamic, natural, relaxed and uncolored than most mids I encounter from other, even much more expensive speakers with smaller, more "exotic" midrange drivers. Perhaps the best mids I've ever heard comes from 3' diameter fiberglass JMLC-horns (300 - 3.5kHz) driven by compression drivers as well - go figure. |
08-22-14: Timlub
Johnnyb53, are you saying that all 6.5 inch drivers start beaming at 2086hz....???
Actually no; it's not that simple. The significant measurement is the actual moving cone's diameter. A 6.5" driver with a large surround might have a 5" cone, but that would still beam at about 2700 Hz, somewhat shy of 3K. However, this can be offset by a 1st order slope for the tweeter crossover. If a tweeter crosses over at 3K at a 6dB/octave slope, then it's still putting out significant output at 1.5K, and would be down only 3dB at 2250Hz, which would be enough for good dispersion at the crossover point. There are other ways to cheat the dispersion formula somewhat with phase plugs, waveguides, and whizzer cones. Still, I mentioned the formula with a link to the wavelength calculator to answer the OP's question--why have a small diameter midrange when a larger one would provide larger radiating surface? One answer is that the larger driver has the potential to create an in-room 1/2-octave wide suckout around the crossover point. A better solution might be dual mids or dual or triple tweeters. Dual small mids would provide more radiating surface while maintaining small diameter diaphrams for better dispersion. Multiple tweeters would allow using a lower crossover point without overdriving the tweeter. This is what Tekton does in mating a 10" woofer with a 1.5" ring radiator. Some of the 10" woofers have whizzer cones with 3 tweeters instead of one on his top line models. This enables lowering the crossover point to let the tweeters cover for the woofer's beaming. The worst case is a 2-way with a large woofer, small tweeter, and 4th order (24 dB/octave) crossover to increase power handling. It means the tweeter wouldn't be able to improve dispersion just below the crossover point because output would be too far down to help out. Why do you think there are so many speaker manufacturers and DIYers? Dynamic speakers in boxes present balancing acts with an infinite number of possibilities in driver sizes, driver numbers, crossover points, crossover slopes, as well as cabinet size and bass alignment. Not to mention the actual individual driver characteristics. |
Hi Ptss,
I've been down this road before, I won't push it, but I've been in the discussion of calling a frequency peak vs reduced dispersion before. I've experimented with curved cones, phase plugs and even flat cones.... I have found some variance in dispersion characteristics. overall the formula is accurate, but I can't say it is cast in stone.
I'll leave it at that and hope that makes sense. |
It's not hard to look up Tim. |
Johnnyb53, are you saying that all 6.5 inch drivers start beaming at 2086hz....??? |
Johnyb53, I cannot hear that. Perhaps others couldn't hear it either since it received whole bunch of awards including Absolute Sound "Speaker of the Year" 5 years in a row, Enjoy the Music "Best of 2004" and "Decade Award", Stereo Times 2005, 2006 award, Blue Moon award and many glowing reviews like this one: http://hyperionsound.com/Images/Hear%20the%20Hype_low_res.pdfPerhaps one shouldn't judge speaker sound by one calculation? |
If you consult the wavelength calculator, you'll find that a 6.5" driver starts beaming at 2086 Hz, whose wavelength is 6.5". By the time you get to 3Khz the wavelength is 4.5", which would be a total beam from a 6.5" driver. This beaming isn't noticeable on-axis, especially if you're listening nearfield, but it disrupts the in-room power response and you'll get cupped-hands sounding suckouts right in the midrange where it counts when you have too large a midrange crossed over too high to the tweeter. A 6.5" mid crossed over at 3Khz will beam from 2K to 3K Hz--1/2 an octave in the midrange. |
6.5" midrange drivers in my Hyperion HPS-938 speakers
cover range of 230-3000Hz. They have ferrofluid suspension
instead of traditional "spiderweb". Here is what
hyperion says about it:
"The Magnetic Fluid Damping System (M.F.D.S.) is
another innovative design for our revolutionary speaker
drivers. The S.V.F. driver does not have a spider, which is
an essential part of conventional speaker drivers for
holding and stabilizing the sound coil. Although the spider
is important for conventional speakers, it is also
considered as a source of vibration and sound coloration.
Our M.F.D.S replaces the spider completely, increases the
driver speed dramatically, and enables the purity of sound
reproduction."
[url]http://www.hyperionsound.com/HPS-938.htm[/url]
These relatively inexpensive speakers have one of the best
midrange I've ever heard. Unfortunately company went
bankrupt in spite of very good product (poor marketing, poor
dealer base). |
08-21-14: Dweller
Ptss: So you're saying that most of everything emanating from a symphony orchestra can be reproduced by a five inch driver? A symphony orchestra has a very large range of frequencies which extend well beyond a 5" midrange driver. So, no the 5" midrange driver cannot reproduce all those frequencies. the speaker would need to be multi-driver where the midrange will reproduce everything in the, say, 300Hz - 2500Hz region (assuming that the midrange driver's freq response is flat over this region & that there is no cone break-up). I think we're just brain-locked into the current paradigm and are waiting for our "Einstein" to show us the way to the next level. The Einsteins have come & gone. I believe it's up to you to understand why certain driver choices have been made for the various speaker designs. See if you can talk to your speaker designer or tech support of your particular speaker & see if he is willing to share his thoughts on the driver choices of your speaker. It might be enlightening to you.... |
08-21-14: Dweller
Ptss: So you're saying that most of everything emanating from a symphony orchestra can be reproduced by a five inch driver?
I think we're just brain-locked into the current paradigm and are waiting for our "Einstein" to show us the way to the next level.
We've been shown various paradigms concurrent with the development of the loudspeaker. Klipsch horn loaded everything starting in 1949. The electrostatic has been around since 1919 and has had a presence in high fidelity since the mid-'50s. The Magnepan has been around for 45 years, and the Heil air motion transformer has been in production for 44 years. Even within pistonic loudspeakers, there are variations such as high excursion drivers, line arrays and other arrays of multiple drivers, downfiring woofers to couple with the floor, transmission lines, etc. Personally, I choose the planar magnetic. My humble Magneplanar 1.7s have 509 sq. in. of diaphragm area per speaker, and in my experience provides a decided advantage in preserving clarity and voice placement in larger works, such as full scale orchestra plus 100+ voice chorus. Each of these driver designs presents strengths and weaknesses unique to each design. We're left to pick our poison. |
Ptss: So you're saying that most of everything emanating from a symphony orchestra can be reproduced by a five inch driver?
I think we're just brain-locked into the current paradigm and are waiting for our "Einstein" to show us the way to the next level. |
If you are after realistic dynamics, try using front-loaded horns driven by compression drivers. Perhaps Danley has something you might enjoy. They are commercial speakers and look it but they get the job done like few others. For better looks in horns, expect to pay dearly unless you are able to score a deal on the used market. |
Revel Salon use about 4.5 inch drivers for good reason. Look into driver size, dynamics and dispersion. |
