Change to Horns or stay Dynamic

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.

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

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

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

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.

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

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

"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.

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