A waveguide is generally shallow and has a wide throat with no compression chamber. A horn loaded driver uses a compression driver mounted behind a deeper horn.
A waveguide can control dispersion and allow for a much better match between drivers - it is very useful and completely underestimated by most designers.
As a conventional woofer driver starts to beam at the top of its useful range then you can limit the dispersion of the tweeter with a waveguide to get a completely smooth transition.
Another trick is to extend the useful LF range of a driver a little in order to get a better crossover point and a device that will give 6db higher output without distortion at is lower opertaing range (where Xmax starts to be an issue).
Waveguides are essential to good speaker design, IMHO...
Interestingly B&W go completely against this philosphy with their baffleless tweeters mounted on top...inevitably the transition between midrange and tweeter is most evident in the off axis response which often shows a discontinuity that is distinctly audible but also regarded as pleasurable by B&W owners. IMHO, depedning on the room setup, it can make one all too aware of the fact you are hearing sound from three or more drivers... |
Hi All
I am Earl Geddes and I do think that Waveguides are unique from horns. To me they are not the same thing. The theories behind them are completely different.
I'd be happy to expound in more detail on the differences, but that's best done through questions than my just writing a monogram on the subject.
On my website www.gedlee.com there is a letter to Audio Express which outlines the general ideas. That's worth reading as a start.
And as far as my website goes, I am a scientist not a web designer. My web designs are better than a web designers speaker designs - thats about all I can say. |
Try to listen to Tactrix horns or LeCleach profiles too, new profiles, implementations and time alignment clean out the tipical horn sound, I had a lot of Vintage horns from Altec Valencias to Hartsfield toploaders and the newer versions are way more sophisticated and better sounding. |
Fair enough. I have heard most of the highly touted, and might I add fairly expensive horns, but not the Geddes "waveguides". I will try to remember to make an effort to do so. If the Geddes "waveguide" systems are indeed so different, perhaps they shouldn't be grouped with horns at all? |
Unsound, many horns do sound quite nasty. I have yet to hear a prosound hornspeaker that doesn't, especially at high volume levels.
Two potential sources of nastiness are frequency response problems and diffraction. Horns all need some sort of equalization, and usually fairly complex equalization, before their frequency response is reasonably smooth. Not all designers go to the trouble to smooth the frequency response - perhaps because many horns still sound edgy even after they measure smooth. Which brings us to the second problem: Diffraction.
Diffraction occurs where there is a fairly sharp discontinuity in the horn flare or profile. For example, many horns have a fairly sharp-edged mouth, which results in diffraction at the mouth. Others deliberately induce diffraction within the horn to widen the radiation pattern. Diffraction has little measurable effect on the steady-state frequency response curve, but it's audible because of where it occurs in the time domain: Just a little bit later than the original sound. The ear is good at masking (ignoring) a lower-level coloration that occurs at the same time as the main signal, but very poor at masking a coloration that occurs later in time. Also, the ear's sensitivity to the type of coloration diffraction imposes is level-dependent; that is, diffraction becomes more audible (and more objectionable) as the level goes up. Those prosound horns that drill your ears at high volume levels - that searing edginess is probably diffraction (and higher order modes - a diffraction-like phenomenon that occurs within any horn, but is worse in some than in others).
So to get back to Unsound's comment, not all horns are created equal, and not all horns are employed equal. In fact, historically low coloration has not been the top priority in horn design, perhaps because knowledge of how to build a truly low-coloration horn was lacking. Dr. Earl Geddes is the leading expert on low-coloration horn design; he calls his devices "waveguides" to emphasize that their function is guiding the sound waves (controlling the radiation pattern), rather than acoustic amplification. The "horn" that I use is a Geddes-inspired waveguide.
Duke |
Horns sure have their fans, but to my ears, they sound nasty. To each his own, YMV, etc.,etc.. Unsound, I agree that horns can sound harsh and have colorations and just plain sound bad, but what loudspeaker technology doesn't have it's bad examples? Factors affecting horn performance include abrupt mouth termination, discontinuities in the profile (diffraction horns are notorious for this), forcing a horn to play outside of it's design bandwidth etc. I am sensitive to horn artifacts and the main reason I originally brought up these two speakers is because by all accounts they do not have the traditional horn sound. Lynn Olson, a well known speaker designer and a person that by his own admission is very sensitive to horn honk, was impressed by the Jazz Module when he auditioned it at one of the shows. Keep in mind that both the Summa and the Jazz module use waveguides, that are shallower than wide with straight sided walls and have smooth round-overs at the mouth termination. As i mentioned earlier waveguides and the theory behind them, have been developed by Dr. Geddes who is also the one that coined their name. Suffice to say that there are key differences between waveguides and horns. This last statement does not of course preclude the fact that horns can sound good and some actually do so, namely some examples of the pro monitors mentioned by Shadorne. George |
Horns sure have their fans, but to my ears, they sound nasty. To each his own, YMV, etc.,etc.. |
So Change to horns or stay with cones?
I guess this is the right answer not in my words:
Your argument about home audio listening is valid if you listen at fairly low average spl levels of lets say, around 75db. Because for a good sense of dynamics a loudspeaker must be able to easily handle 20db peaks above the average level with no compression. That is the minimum requirement and unfortunately the Scan-dinavian favorites (the drivers used in most high end dynamic speakers) fall short of this target at anything above mid 90's db. So if you want to listen at realistic average levels of say 95 -100 db you will need the speaker to handle a not-so-unrealistic 120db peak levels and that's at the listening position no less.
For audiophile drivers core size and voice coil size are of secondary importance. Contrast this with the pro drivers' big voice coils and oversized and vented magnetic cores that can sustain prolonged periods of abusive power (read 400-600 watts) with just maybe 2db of thermal compression while playing at around 120db average level. There really is no comparison! Thermal compression is real and one of the most important as well as overlooked parameters in loudspeaker performance. It's perhaps not surprising that this is the case for the audiophile speakers as the driver core is the most expensive part of the assembly and the designers using the same logic consciously chose this set of compromises.
But make no mistake, as excessive as these db levels might seem at first, for the person that wants realistic reproduction at the home this is what will be required of the system. (Manga)
Is there a need for an audio system to produce 120 db peak?
Symphony orchestra is playing one flute, but in the next second the orchestra barks with the whole power.
Most of the brass instruments can alone produce 120 db. There are 120 or so different instruments in the orchestra.
You are sitting at row 20, a flute is about 40-45 db. The orchestra BARKS. It is about 120 db at the row 20.
The difference is 80 db.
CD can record 90 db of a difference (called dynamic range). Recording engineer has to compress the sound. Some engineers can hide compression better though, but all sounds are too BIG to fit on CD.
No matter what it is, Jazz you name it. I bet to record a girl with the guitar some 6 db of compression is still needed. (Yurmac)
In my opinion the single most important benefit of a good horn is not increased dynamic contrast, but improved radiation pattern control (though it's nice to have both). The radiation pattern of most loudspeakers narrows and blooms and narrows again very significantly across the spectrum. The result is that the reverberant energy - mostly composed of off-axis radiation - has a different tonal balance from the on-axis sound. Since the ear/brain system is constantly analyzing incoming sounds as either first-arrivals or reflections, and using spectral constant to do so, a large discrepancy in the spectral balance of the first-arrival and reverberant sound makes correct classification more difficult for the ear/brain system; in effect, CPU usage goes up. Often the result over a half-hour or so is listening fatigue - literally, a head-ache because the ear/brain system having to work harder to correctly classify the reverberant energy whose spectral balance is unnatural.
But, don't get the idea that reflections are bad - early ones often are, but late-arriving ones are usually beneficial. A dense, late-arriving, highly diffuse, slowly decaying, spectrally correct reverberant field is what makes a good concert or recital hall sound so delicious.
Horns don't ordinarily give a more diffuse reverberant field than direct-radiator dynamic speakers. If anything, their typically narrower pattern results in a less-diffuse reverberant field; but that narrower pattern often makes it easier to "aim" the horns to minimize early-arrival reflections.
You see, reflections arriving before 10 milliseconds (corresponding to a path length of about 11 feet) are usually detrimental, whereas reflections arriving later than that are usually beneficial, assuming good spectral balance. (Audiokinesis)
Wonderfully put by this fellow audiogoners.... |
the radiation pattern of horn speakers are just as important as their increased dynamic contrast That was my point to Dgad early on. Horns are great for dynamics/detail - especially with TAD drivers - just be careful of extremely long throw horns with tightly narrow dispersion as these will beam at you like a spotlight - get a "floodlight" design instead. If you look at pro studio horns (Westlake's, Augspergers and many others) - generally you will always find wide dispersive horns rather than long "victrola" type narrow designs - there is a good reason for this as Duke has pointed out => the reverbernat field needs to match the primary direct signal reaching your ears to a chieve a relaxed pleasing and natural sound. (as per Dr Floyd's many many listening tests that confirmed this in the 70's) |
Duke-
Congrats on the TAS GEA!
Seems like you're saying the radiation pattern of horn speakers are just as important as their increased dynamic contrast. Less negative room interaction = better
spectral balance.
I note that you're a Gradient dealer. Their new Helsinki 1.5, which are designed to reduce room interactions, seems like the ticket to a more natural-sounding spectral balance. |
Dgad,
Thanks for asking for clarification - it sounds like I was giving an incorrect impression.
Horns don't ordinarily give a more diffuse reverberant field than direct-radiator dynamic speakers. If anything, their typically narrower pattern results in a less-diffuse reverberant field; but that narrower pattern often makes it easier to "aim" the horns to minimize early-arrival reflections.
You see, reflections arriving before 10 milliseconds (corresponding to a path length of about 11 feet) are usually detrimental, whereas reflections arriving later than that are usually beneficial, assuming good spectral balance. This is why Maggies and such sound great 5 or 6 feet out from the wall, but have coloration and poor clarity when pushed back against the wall. Likewise, when you see MBL demo'ing their omnidirectional Radialstrahlers they are positioned well away from all walls, again to avoid detrimental early reflections.
A highly diffuse reverberant field arises from a combination of wide loudspeaker radiation pattern and diffusive room surfaces - like book cases and plants and furniture, or even diffusion panels, instead of bare walls or Sonex-lined walls.
In my opinion most loudspeakers don't put enough reverberant energy out into the room, hence my top-of-the-line speaker is a bipole - but if it can't be positioned properly then its monopolar little brother sounds better. My reason for using horns is to control the spectral balance of that reverberant field; the bipolar pattern is where I get my additional diffusion from, and then I like a fairly "live" room as opposed to a "dead" room.
Let me know if this doesn't answer your question.
Duke |
GerryM5,
I am curious what horns you have tried that lead you to your conclusions. I wouldn't say all are equal. That would apply to most speakers. You and I are in a similar place but mybe coming on different paths but I would love to know more. I have heard many a horn that didn't do it. But a few that did.
AudioKinesis,
I am a little confused about horns. Do they actually have a more diffuse reverberant field than dynamic speakers? Does this apply to all horns or to some? I would love a bit more of an explanation in terms of design and what the different benefits are. Thanks. |
Thanks for the mention Manga, and the clarification, Kana813. The ones that got the award are indeed bipolar, kinda like their designer....
The subject of fullrange horns came up. Well, the Edgarhorn (with Seismic sub) and Classic Audio Reproductions Hartsfield are in my opinion excellent examples of fullrange horn systems. And I bet JohnK has some highly competitive offerings of his own in this arena.
As one who builds hybrid horn systems, my vote on "dynamics vs horns" is totally predictable - but probably not for the reason you'd think.
In my opinion the single most important benefit of a good horn is not increased dynamic contrast, but improved radiation pattern control (though it's nice to have both). The radiation pattern of most loudspeakers narrows and blooms and narrows again very significantly across the spectrum. The result is that the reverberant energy - mostly composed of off-axis radiation - has a different tonal balance from the on-axis sound. Since the ear/brain system is constantly analyzing incoming sounds as either first-arrivals or reflections, and using spectral contant to do so, a large discrepancy in the spectral balance of the first-arrival and reverberant sound makes correct classification more difficult for the ear/brain system; in effect, CPU usage goes up. Often the the result over a half-hour or so is listening fatigue - literally, a head-ache because the ear/brain system is having to work harder to correctly classify the reverberant energy whose spectral balance is unnatural.
But, don't get the idea that reflections are bad - early ones often are, but late-arriving ones are usually beneficial. A dense, late-arriving, highly diffuse, slowly decaying, spectrally correct reverberant field is what makes a good concert or recital hall sound so delicious. Indeed, much of the appeal of a good omni or quasi-omni or dipolar system is because of the relatively large amount of beneficial reverberant energy such a system puts out into the room when set up properly.
Some people talk about a good horn system as having a natural-sounding tone, and when you consider that most of the sound that reaches your ears is actually reverberant energy, a good horn's superior off-axis (reverberant field) performance starts to seem like a good idea.
Duke
dealer/manufacturer |
To Gerrum6
You are right about "merry-go-round"
Horns, dynamics, planars are like cars. How can you compare Lamborgini to a Hummer? People tend to replace SUVs with Corvette for no reason. Is there a need for a car to drive 200 mph?
Is there a need for an audio system to produce 120 db peak?
Symphony orchestra is playing one flute, but in the next second the orchestra barks with the whole power.
Most of the brass instruments can alone produce 120 db. There are 120 or so different instrumens in the orchestra.
You are sitting at row 20, a flute is about 40-45 db. The orchestra BARKS. It is about 120 db at the row 20.
The difference is 80 db.
CD can record 90 db of a difference (called dynamic range). Recording engineer has to compress the sound. Some engineers can hide compression better though, but all sounds are too BIG to fit on CD.
No matter what it is, Jazz you name it. I bet to record a girl with the guitar some 6 db of compression is still needed. |
I done horns, planners and dynamic speakers - some a couple of times. It was fun, painful and rewarding. Each time I settled on a speaker type I had changed out other components to better match that speaker type. So figure that in too, because it will happen. Now i got off that merry-go-round and picked dynamics, third time, for better all around performance (IMHO). You may decide something else. My only advice is get the dealer support you deserve. Insist on it.
How many responses on these thread where from dealers? Bet there are a few and that's good. Why not sept up to providing a home demo, free or not, of some of these expensive horns? This might be difficult to arrange, but once you narrowed down your preferred horns to three. Find dealers that will do that home demo. |
This loudspeaker also uses pro-drivers made by TAD and Beyma. See a trend here? Sadly - the use of pro drivers is all but ignored - however a nice shiny aluminium driver with stunning shiny copper phase plug => that will catch the eye everytime and have audiophiles reaching for their credit card everytime - especially when the listener is reminded about how fast these small lightweight woofers are and how plodding the old dumb sound reinforcement dated big woofers of the 70's JBL crowd are.... Furthermore a big ugly black paper Volt woofer with massive 3 inch voice coil and a massive frontal ribbed heat sink which is also ugly black to help dissipate heat and reduce thermal compression and as used on PMC speakers...no that is butt ugly and so out of place among those tall slender veneered beauties...forget it...most dealers won't even carry this kind of monster! As Jaybo puts is so well - some audiophiles hear what they see! |
Kana,
Oops! Guess you're right.
Although this is the case it should also be known that the Dream Maker uses the same drivers arranged back and front in a bi-pole configuration, so it's sonic signature should be close to that of the monopole. |
"The Jazz module is similar in design to the Summa. It has recently received a golden ear award from TAS"
The TAS GEA was given to Duke's Dream Maker. |
"Bear in mind mastering engineers compress the crap out of what you mostly can buy in recorded music - so you won't always achieve realism except on recordings where dynamics have been deliberately preserved" Excellent point, very well said and perhaps a topic deserving it's own discussion under the heading "atrocities sound engineers commit during post mastering" although I have a feeling it's been discussed before. |
Shadorne,
Thanks, and right you are about the tweeter sized woofer voice coils of the north european drivers. Very well put.
To further my point, let me say that in addition to the Summas' reviews that more than anything else cite that speaker's unrestrained dynamics, there's another loudspeaker that I mentioned earlier, the Jazz module by Audiokinesis (Duke Lejune by the way, is the designer and is one of the nicest and most helpful posters right here on the Audiogon forum). The Jazz module is similar in design to the Summa. It has recently received a golden ear award from TAS and the word on the forums from people that have heard it is that it too excels in dynamics being able to play very loud without compression. This loudspeaker also uses pro-drivers made by TAD and Beyma. See a trend here?
It's also worthwhile to note that in all the reviews of both of these systems, people are reporting the lack of horn coloration and horn-honk from the waveguides. So, the reason I am excited (even though I haven't heard either of these two yet) is that you can finally have your cake and eat it too having the dynamics of horns with out the artifacts.
Cheers,
George |
For audiophile drivers cone size and voice coil size are of secondary importance. Contrast this with the pro drivers' big voice coils and oversized and vented magnetic cores that can sustain prolonged periods of abusive power (read 400-600 watts) with just maybe 2db of thermal compression while playing at around 120db average level. There really is no comparison! Agreed - "there really is no comparison". I'd re-iterate to try Shefield Labs Drum Tracks on a pro design speaker like (PMC, ATC, Meyer, Westlake, custom Augsperger and many other pro designs) and your audiophile ears are in certainly in for a big surprise...hey that actually sounds like a real drum set in the room! (Bear in mind mastering engineers compress the crap out of what you mostly can buy in recorded music - so you won't always achieve realism except on recordings where dynamics have been deliberately preserved.) |
Thermal compression is real and one of the most important as well as overlooked parameters in loudspeaker performance. Absolutely...northern european woofers with a voice coil the size of a mere tweeter and a metal phase plug to try and keep cool the pole and connected to a lightweight rigid driver work well up to mid 90's at 1 meter. Great engineering for great sound at modest levels for low cost but far from realistic reproduction. On the other hand - money saved from purchase of expensive drivers can go into woodwork and veneer to create a work of art... Great point George! |
Dgad: You bring up a common misunderstanding about active systems. Many do have built-in amps, but that's not necessarily a given. Some use external amps, e.g., Linkwitz Lab Orion, Gradient Revolution (I think), Morrison, Nomad Ronin, among others, including what I build.
Yes, the initial set-up is a little more involved, but once you've got it connected, you're done. The gains of active out weight the extra work. And if you want control, an external active x/o allows for far greater control than a fixed internal passive.
Here's another link that goes into the specific benefits of active: http://www.tnt-audio.com/casse/active_speakers_intro1_e.html |
Pacific,
Your argument about home audio listening is valid if you listen at fairly low average spl levels of lets say, around 75db. Because for a good sense of dynamics a loudspeaker must be able to easily handle 20db peaks above the average level with no compression. Thats the minimum requirement and unfortunately the Scan favorites fall short of this target at anything above mid 90's db. So if you want to listen at realistic average levels of say 95 -100 db you will need the speaker to handle a not-so-unrealistic 120db peak levels and that's at the listening position no less.
For audiophile drivers core size and voice coil size are of secondary importance. Contrast this with the pro drivers' big voice coils and oversized and vented magnetic cores that can sustain prolonged periods of abusive power (read 400-600 watts) with just maybe 2db of thermal compression while playing at around 120db average level. There really is no comparison! Thermal compression is real and one of the most important as well as overlooked parameters in loudspeaker performance. It's perhaps not surprising that this is the case for the audiophile speakers as the driver core is the most expensive part of the assembly and the designers using the same logic consciously chose this set of compromises.
But make no mistake, as excessive as these db levels might seem at first, for the person that wants realistic reproduction at the home this is what will be required of the system.
Cheers,
George |
I dont feel active has any advantage in sound quality over well designed passive, you will get greater dynamics for you are running multiple amplifers with an active and a bit less insertion loss over passive but this is a nonissue if networks of proper design. I agree that "well designed" is far and above more important than active or passive...good drivers and good drivers selection and implementation is fundamental starting point for a good speaker no matter how it is amplified...which is why I trust design to experts like yourself! although.... How about eliminating IMD and higher order harmonic crossover distortion from an amplifier for a large bass woofer driving both a woofer and a tweeter? Correcting for Phase? How about using a Class AB for the woofer and pure class A for the tweeter? Fundamentally there seems something at cross purposes in most passive designs where you hook up the same power source to something as delicate and sensitive as a tweeter (milli amps) AND to something as big and powerful and thunderous as a bass woofer (amps)... Active Speaker Proponent |
I dont feel active has any advantage in sound quality over well designed passive, you will get greater dynamics for you are running multiple amplifers with an active and a bit less insertion loss over passive but this is a nonissue if networks of proper design. A well designed 1st order will not limit dynamic range. I will say its easy to design a loudspeaker for active crossover much harder to design proper passive networks. For awhile I ran a 4 way horn system with active crossovers had 8 mono amplifiers what a pain to get it all right so many cables so much to go wrong. Still I use active for crossover designing. Gets me in the ball park so I have to exparament with values a bit less. |
Pacific Island,
I have heard some excellent active systems. The main negative with them, is that the market is unresponsive to them. I think, audiophiles would rather be able to choose thier amps then have them dictated. Yet, I am in agreement that well executed active systems (I have only heard a few, not ATC or PMC yet) can easily outperform most passive systems in terms of dynamics. A speaker that truly surprised me was Backes & Muller that is fully active with what appears to be a digital crossover or something similar. But the price was close to 100K fully executured. |
Johnk, yes, thoes horn bass units do get huge and expensive, fast.
Dave |
My horns systems never cop out in the bass. Horn bass has wonderful detail notes are not lost to drivers massive movements, its fast with less distortion than convetional designs, plus the amazing bass pressures one can generate with ease realy the only -s are size and cost. If you can get around that then horn bass to me is the best reproduced bass can get. |
There's no denying horns win hands down in the efficiency and dynamic department. This is why they are used for high SPL applications. Yet, all driver types have their advantages and disadvantages. Keep in mind that we're talking about *home* audio. This is not the large scale amplification that very big spaces need. So, do we need horns to accomplish our goals at home? Conventional cone/dome drivers can provide ample SPLs and dynamics (in a well designed system) for home-scale rooms without the drawbacks (cost, size, limited dispersion) of horns.
One solution is to get rid of the passive crossover. Active systems eliminate the power loss of passive crossovers allowing for greater dynamics while also providing other benefits. For home audio, this is a viable, cost effective alternative that takes advantage of fewer compromises. |
Dgad, you nailed it. The room, even treated, will likely produce more distortion to the frequency response curve than the speaker's curve is off-kilter in the first place.
I would, however, take issue with people's ideas that horns "cop out" in the bass. The worst that happens (if you choose your implementation), is as good as any other form of woofer section out there. |
Dave,
Dr. Geddes teamed up and went into a partnership with a music producer / sound engineer to manufacture and market pro-sound loudspeakers. The company, AI Audio is based and operates out of Thailand. The ESP15 is the Summa, using the same drivers as the original but with a somewhat different cabinet construction to save on costs. There are two other smaller speakers using 10" and 12" woofers that are just scaled down versions of the esp15. Sorry but I am really not sure on the availability of the Thailand products but the Summa is probably made to order. As per Dr. Geddes the specs of the esp15 shown on the AI website are the same as those for the Summa.
As for him exhibiting in any of the shows he has stated in the past that that is not going to happen. Only way to audition is in his home or possibly in one of the homes of the few owners of the Summa. He lives somewhere in Michigan and if I am ever close by I 'll certainly try to have an audition.
Here's another review:
http://www.audiocircle.com/circles/index.php?topic=24627.msg218373#msg218373
Hope this Helps
George |
I read the review of the ATC. Has me very interested. All the recommendations here are excellent. But listening & time are the limitations.
In the end there seem to be few choices for ultimate dynamic capabilities outside of Horns. And yes, bass is an issue. But I do believe there are some great horns w. bass. I need to hear it myself. Most people don't have the room big enough to sustain bass in thier rooms properly. |
even the largest horns cop out in the bass(falling back on a driver in a box), and in some cases the highs.... |
Dgad, It is funny how ATC & PMC have not been as successful in the US as other companies. You need to hear one of their "ugly" three ways playing Sheffield Labs drum tracks in order to immediately understand why pros go for them. They are definitely overkill for most peoples requirements. PMC have better marketing than ATC as ATC rarely if ever advertise. Incidently, an astrophycist that uses PMC recently handed in his PHD. So if you go "active" you will be joining a rarified crowd along with Mark Knopfler, Pink Floyd etc ;-) |
Thanks Manga. So, is the Summa a modified Ai???
Ai is from Asia and Summa is in the US, I think. That guy really needs to bring his site into focus. Like so many brilliant people he has trouble presenting what he's all about.
Will he be at RMAF this year?
Dave |
well live music is horrifically over amplified, so i am not surprised you would feel fatigue. Some speakers do "sing" a little more at higher volumes, but most good speakers will sound pretty good at both low and high volume within reason.
I am not up on all these new horn designs, but i worry about the usual horn issues of getting proper bass and placement. The planar camp deals with these issues too. |
Dave,
On the above links you will just gonna have to scroll down a bit to get to the posts that I am referring to. I agree that the site needs work if he is going to promote the product but Dr. Geddes is a scientist and an author and places more emphasis on the theoretical aspect of speaker design. He has said that he 'd rather license the technology than produce speakers himself.
AI Audio is/was his attempt to branch out into the pro audio arena and teamed up with a sound engineer/producer partner. The company is based in Thailand and it's not clear if production is ongoing and if any product is imported into the US. The Summas that have been sold in this country were made by the man himself in his own garage. |
Dave,
Here's a few links to reviews and impressions on the Summas:
http://www.diyaudio.com/forums/showthread.php?postid=1507485#post1507485
http://www.diyaudio.com/forums/showthread.php?postid=1527971#post1527971
http://www.diyaudio.com/forums/showthread.php?postid=1532393#post1532393
To see what the speakers look like go to:
www.ai-audio.com/factory.html
Hope this helps |
All I can find about Geddes' Summa is talk and theory, but no real reviews. Their web site absolutely sucks. Anyone got a picture of one of these???
Dave |
darren, sounds like you and i are after the same thing; after listening to the WP6s for years, i'm growing tired of their distortion, their blurred microdynamics, and the lack of dynamic expression...despite wilsons being the most dynamic monkey coffins i've heard.
the ? to you in your experience w/ cessaro et al: how'd they do w/ a drum kit? bass guitar? seems like this hobby is all about compromises, and horns mean you compromise the bass & weight of the performance, or you compromise your domicile with a gigantic speaker.
ATC might be an interesting solution.
best |
Two horn speakers with your stated requirements of wide dynamic range with low distortion at high output levels are the Summa by Dr. Geddes and the Jazz Modules by Duke Lejune of Audiokinesis. I have heard neither of the these speakers but the general consensus in the various forums is that for both loudspeakers these are the main characteristics where they excel.
It may not be coincidence that the design philosophies are similar in both cases. Both Loudspeakers use high quality pro drivers and waveguides for the compression drivers and are constant directivity designs. Dr. Geddes has done extensive research in distortion perception and dynamic compression issues in loudspeakers, has put forth the Waveguide Theory (as opposed to Horn Theory) and holds a number of patents related to loudspeaker design.
I Have no relation nor have I ever met Dr. Geddes but I have been impressed with the depth of his knowledge in his postings. For a crash course and to deepen your knowledge and understanding of horns and waveguides do a search on diyaudio.com under the author "gedlee". Oh, and by the way both of the aforementioned choices will leave a chunk of mullah in your wallet compared to the high-end darlings of today!
Cheers,
George |
Shadorne,
It is funny how ATC & PMC have not been as successful in the US as other companies. The truth is, they don't have the looks or the WAF to make them special. I am going to make the effort to hear them, as too many ears I respect have migrated to this direction. It is a gap in the market that really needs filling. I heard a wonderful speaker in Munich that I would almost accept. Backes & Muller. A German brand with some truly unique design elements. The sound was incredible and they use a unique "horn" type tweeter with active amplification. I didn't read a lot about it but it was one of the best sounds at the show. Something special. The price was also "special" in the 60-100K range at least.
As far as eye watering abilities, I am going to merge this conversation w. Exlibris question and do a redirect on the thread.
Exlibris,
It depends on what we listen to as our reference. The truth is a true live concert leaves me fatigued. That is for Rock & Roll. Classical is a different stor as is Jazz. But there is pressure and it can be fatiguing. I think live music is fatiguing at times as well. Especially anything with a large group. We feel the pressure.
So my question is - are we able to live long term w. the pressure or do we need 2 systems. I think the pressure will get to be much at a certain point. But any large venue does produce sound pressure/air pressure. From the crowd the room etc. Have you ever been to a restaurant w. poor acoustics. I find leaving the restaurant to be a relief after a point in time.
Is the pursuit of live vs. "musicality" in conflict. Is that why many people use SETs for horn systems? Mind you many people are using class D amplification or digital amplification on horns these days. I have a feeling that is probably too honest for long term listening enjoyment.
I am speaking in circles but at some point this hobby is steering me and many others in circles.
I just went to a live jazz show last night and I didn't find the pressure too much. But the room was very large and it allowed the sound to relax. and not overload the room. I guess the speakers we buy determine what venue we want to be inside. |
Sirspeedy,
You have the right guy. It was nice meeting you at the show. That room didn't do much for me. I just wanted to give it a chance.
Rhyno,
Found it a few days ago. Thank you. Romy seems to really hit a few key points in his analysis about horns that line up exactly with what many others say & with what I have heard.
The bass speed & extension limit remains the most difficult to circumvent without having tremendous horns. I need to read more. One thing I will say for sure, understanding design first will allow a more informed choice in speakers. It will also help explain what we hear. The problem with 20 Hz in a horn is the size requirements and length of the horn. Hence all the back loaded horn designs etc. |
Just quick note from Wikipedia about Woodstock 1969.
Do not think it is irrelevant to home listening.
JBL D140 drivers and Altec horns in good condition is almost impossible to find.
"Sound for the concert was engineered by Bill Hanley, whose innovations in the sound industry have earned him the prestigious Parnelli Award. "It worked very well," he says of the event. "I built special speaker columns on the hills and had 16 loudspeaker arrays in a square platform going up to the hill on 70-foot [21 meter] towers. We set it up for 150,000 to 200,000 people. Of course, 500,000 showed up." ALTEC designed 4 - 15 marine ply cabinets that weighed in at half a ton a piece, stood 6 feet straight up, almost 4 feet deep & a yard wide. Each of these woofers carried four 15-inch JBL LANSING D140 loudspeakers. The tweeters consisted of 4x2-Cell & 2x10-Cell Altec Horns. For many years this system was collectively referred to as the Woodstock Bins"
And now for people who hate math, but have money.
Horns are very simple to understand. Sound pressure is not a linear but logarithmic function:
1. You start at 1 watt.
2. To get first 10 DB above your speaker's sensitivity you need 10 Watt
3. To get second 10 DB you need 100 Watt
4. To get third 10 Db you need 1000 Watt
5. So if you draw the curve.
Your DB's are on vertical scale Y, and your Wattage on horisontal scale X.
From 0 to 1 watt it is almost steeply upward. First watt is the most linear part of the curve.
6. From 1 to 10 watt it is flatten up to ~ 45 degree (compression starts to build up)
7. From 10 to 100 watt the curve goes only 15 degree uphill
8. From 100 to 1000 watt the curve is almost horisontal. You pump 600 more Watts and get 1 db more. Ha Ha.
With horn I have 111 DB with one watt. Nondistorted linear 111db. To get those 111 db with the cone speaker (Sens. 85Db at 1 watt) I need to pump ~750 watt. Guess how heavy the coil will be to handle 750 Watt.
Think.
|
Kana813,
Disappointed? Not really. In this hobby I know only too well that "you can have anything you want, you just can't have everything you want."
My guess at this point is that there is a 90% chance that I'll stay with the MBLs and a 10% I'll buy something else.
I'm told that there will soon be a mkII version of the 101Es with a new upper midrange driver. That just may do the trick. |
Thanks exlibris. There are a few places in Japan with ridiculously large horn systems. I would love to visit a place like those on the ACA page but have no idea if any are open to the public... |
Exlibris-
None of the amps you've tried or mention can generate the
2.2kW peaks your speakers are capable of handling.
The Spectron Musician III SE Mk. 2 monos can deliver 7000 watts (and hold it for 500 msec).
But like you say, "the problem isn't amplification, itÂ’s the drivers."
It must be very disappointing to spend over $40K on speakers and find out their drivers come up short of the volume levels you want.
Good luck with your search for new speakers. |
darren
for more on horns, see
http://www.goodsoundclub.com/Forums/ShowForum.aspx?ForumID=32
anyone have any thoughts on how a horn would do in a small (15*11) room, w horns on 15' wall?
best |
I went from electrostats to omni-directionals. Your speakers look very cool. I also like the idea of building a house around horns like they do in Japan. |
