Why Synergy horns?

In another thread I was asked, if I would provide more details about my speakers, so I thought why not?

I have played on active 4 way horn systems since 2016. First iteration was front loaded bass horn, midbass horn, tractrix midrange horn and tractrix tweeter horn. I worked nicely, with all the attributes associated with well implemented horns. Clarity, dynamics, realistic live sound etc.

However some problems will arise, with such horns. First of all, the center to center distance between the different horns is big, compared to the crossover frequencies. We need to be within 1/4 wave in distance at x-over for a seamless transition. For instance if you x-over from the midrange horn to the tweeter horn at 3 KHz the c-to-c distance would have to be 340/3000/4= 2.83 cm (1.11 inch). This is virtually impossible with "normal" horn configurations. This problem rears its ugly head, at every x-over throughout the audio frequency range. As frequency decreases, the wavelengths gets bigger, but so does the horns in the specific bandpass and then c-t-c also increases. It is a linear problem, that can't be solved with the regular approach, aka stacking horns on top of each other. This creates interference problems and lobing in the vertical response curves, that will color the reflection from floor and ceiling. Secondly a large column of vertically stacked horns, will push the sweet spot (SS) further back, for the horns to be perceived as more coherent and integrated, with one another.

But the biggest problem is that almost all horns beam with increasing frequency, it's their way of nature so to speak. What that means, is that the off-axis FR will not be similar to the on-axis FR. This translate into a poor power response, which is not considered a good thing, in terms of best sound quality.

Luckily we can circumvent all these problems with clever engineering and have our cake and eat it too, so to speak. Enter the Synergy horn.

 

The BBC dip is often needed due to crossover in a very audible area (phase anomalies), uneven frequency response, lack of uniform directivty, cabinet diffraction, and poor acoustics. So typical speakers in a modern home will often need to cover up weaknesses, so things can sound smooth. And of course, poor recordings doesn't make it easier.

 

Another listening experience and very fresh in my mind, as it is from yesterday. I got to hear the brand new Dali Epikore 11 speaker, costing 40.000 euro or 60.000 $, so a much steeper price if you pay in dollars. A ton of RD went into the making of the Dali speakers. New motor structures, easy amplifier load, bass drivers with different x-over frequencies to prevent floor bounce suck out. The tweeter is 35 mm, so double the surface area of a normal dome, but to have even dispersion higher in frequency it is coupled with a ribbon tweeter, coming in at 10 KHz.

I can, hands down, honestly say that this is the best monkey coffin speaker I have ever heard. It just took 10 sec. to realise that his is something different. Incredible dynamics, clarity, power and slam, almost horn like, a sort of a homecoming An impeccable detailed sound, the center image and soundstage surprised me again and again with details and a precision, I have not heard before, with well known recordings. In the scheme of this, it's price almost seems reasonable and compared to the competition, it is heads and shoulders above. If I wasn't a DIY guy, I could happily live with this speaker and be a happy camper and I can't say that with many speakers.

 

Divide the price by 10 and you have a winner

 

How can two spaced tweeter drivers lead to a more even dispersion?

 

Bjorn, the 35 mm tweeter will start to be more directional in its upper passband, so the ribbon tweeter is coming in above 10 KHz, but of course this will only work in the horizontal domain.

 

Divide the price by 10 and you have a winner

Sure, 40.000 euro is a lot of money so it's all relative, but compared to the general "high end" jewelry, I think Dali Epikore 11 really delivers at this price point. The research and development that went into this speaker, will surely trickle down, just like we see it from other brands like KEF, Bower & Wilkins etc.

 

In the forthcoming months there will be a series of speakers, that I'm going to audition. A guy called Morten Stjernholm, has assembled a team of 8 or 9 hifi enthusiast (audiophiles?). We are going to listen to the speakers one by one, as not to bias each other and then Morten is going to sum up the reports. There is no affiliation of any kind. Some companies have even turned down the offer to get their speakers (and other gear) reviewed, because Morten has said from the beginning, that it will be honest reviews, where nothing will be left out, buried or hidden with flowery language. The speakers for review will be in the more exclusive segment like the Dali Epikore 11.

 

There is a little side story to my Dali session. As mentioned we are a team of 8-9 people, who independently, are gonna listen to different speakers, in the near future. A fellow named Lars, who had been listening to the Dali's a couple of days before me, had had some trouble of getting a correct soundstage and image from the Dali. He had tried different toe-in angles, even tried some toe-out on the speakers and nothing had helped. So he came late afternoon after I finished my critical listening. I had never met him before and we said hello and then I just sat at the dining table with a cup of coffee. I did not tell him anything about my impressions of the Dali. Lars sat down in the sweet spot and ran through 4-5 tracks and then he jump up and said "this is the best speaker I have ever heard". Quite funny

We never found the "fault" of his first impression with the soundstage missing and all that, although it was carried out with a different amp and DAC. Morten and Lars were also sure that all cables was connected properly. We switched back to the amp and DAC from his session and nothing was wrong, so maybe Lars just had a bad earday, who knows?!

 

Well, let's look as some technical aspects of the design.

Vertically this speaker has large amounts of combing and polar lobing. And crossover in areas that is very problematic. Coherency wouldn't be good. There's no time alignment between the drivers, meaning the sound will arrive at different times to the ear. The horizontal directivity is likely ok (would need to see a polar), but it's not constant particular low in frequency. Baffle step isn't very low, so sound will start to radiate backwards with less sensitivity in that area. Despite of the hefty price tag and curves on the sides, the speaker has some edges and drivers are also mounted on top of the baffle, and thus suffering some cabinet diffraction. It's a passive speaker design where power is lost and distortion increases (i.e thermal distortion).
While the several woofers may reduce the floor and ceiling interaction a little, the result of that is overall small when you use limited amount of woofers. Some will also increase the floor bounce compared to some of the others. The speaker will have a wide vertical dispersion, meaning high amounts of vertical early reflections that are detrimental.
Not surpisingly, Dali isn't showing any mesurements.

Perhaps you were impressed because there wasn't a better speaker design to directly compare to in the same position/room? This is a fairly common speaker design. Sure the drivers may be of high quality and improved to previous models and I'm not saying it doesn't sound good at in certain ways. But it does suffer from many major weaknesses that are considered very important to sound quality. Sometimes though, we are impressed with a speaker like this right away, but that in the longer run with various music material we start to experience the drawbacks more and more.

 

Thanks for your reply Bjorn! Hopefully the Epikore will be measured by somebody, I would also like to see some polars on these. In the meantime have a read a the "white paper". Some of your objections will be explained.

https://static.hifiklubben.com/4ab9ff/globalassets/01-enricher/10-pdfs/dali-kore/epikore_white.pdf

I'm quite certain that this is the best box speaker I have heard, for all it's worth. We will see how the rest of the "team" will respond.

 

I will add to my impressions of the Epikore, that the speakers totally mastered the "disappearing act". At no time did I have any sense of sound, emanating from the speakers itself. For me, that counts as a strong argument of good and solid speaker engineering.

 

New weekend audio escapades. My friend got the opportunity to get a quick listening session with the Dali Epikore 11. General same impression as I had, reference holographic soundstage, imaging and "speaker disappearing" act. Dynamics and clarity top notch, nice bass even without EQ, but he felt the tweeter, in some areas, was a tiny bit too hot, he would have liked to move the listening chair 50 cm back. Well, he is a bit younger than me and haven't been to hundreds of live concerts



On the same trip, we also played a visit to the founder and owner of Groundsound, which makes amplifies and DSP units. We got to hear his latest DIY setup, with a coax Oberton, with Sica bass drivers and 4 big subwoofers, in a nice big room. The overall impression was good dynamics and the ability to play loud without compression. The tonality was a bit heavy, with powerful but even bass, but on that same token, the music never sounded harsh og pierced, even with full throttle on wind instruments.

 

Fortunately I'm not the only one who thinks that Dali Epikore 11 is something quite special. The other guys at the review team, pretty much agree.

Just for clarification, none of us has any affiliation with the products under review.

 

A new review is up. This time it is another danish speaker Raidho 3.8. They can be yours for around 100.000 $ grand I must admit that I was not overly impressed with the sound, especially the price considered, so most of my review/opinion had to be uhm, how to put it, be diminished or toned down, as Raidho would not accept my criticism.

As I'm a totally independent with no money involved, so I feel that I can spill my beans elsewhere, but on the youtube channel. So what do I think of Raidho 3.8?

First, I don't think that there are any bad sounding speakers per se at 100.000 $, at least I hope that's not the case. On the other hand, I do think that there is plenty of mediocre speakers at all price points, also at a 100 grand and above.

The tonality of the 3.8 is a variation over the common "happy smile" frequency response. Raidho is probably trying to aim at the +middle aged well heeled audiophile, that often has a recessed top end hearing. Along with the lifted bass response, that does not go down that low, I think it is fair to say, that they sound a bit colored.
The Raidho had a wide soundstage, but lacked some image pinpoint focus, between the speakers. A big let down, for me, was that the bass drivers distorted, when pushed a little. It was by no means at high SPL, probably around 95 dB in the listening chair. No louder than I could have a "normal" conversation, while playing music. That was a big "turn off" for me. In the end the Raidho did not "encourage" me to put on more music, so that's that!

 

Interesting, thanks for sharing.
What was the amplification used, perhaps that’s the problem? Also, the room, etc. Is that response done in room?
The reason I often don’t listen to components before buying them is it’s so hard to judge if they are not in your room and with your components. For example, one could reduce the bass hump with room treatment. Pinpoint focus can be achieved with proper setup of the speakers, room treatment (makes a big difference in this regard!), listening position, and even changing a cable or adding vibration isolation under components.
It’s crazy how everything makes a difference!

 

Hi "Doc",

Theses reviews are well done, and entertaining! It is unfortunate that you were not given a little more space to explain your objections, but I think the message still came through.

 

most of my review/opinion had to be uhm, how to put it, be diminished or toned down, as Raidho would not accept my criticism.

Would you say the most essential aspects of your criticism on the Raidho's have been covered in your post above? The manufacturer's unwillingness to accept your criticism in the youtube review confounds me, as other review members expressed a nigh on perfect speaker to their ears, and so one would believe it's only a natural reflection of a diversity of opinion with some being ecstatic and others more withheld in their enthusiasm. Why wouldn't Raidho accept that?

On the other hand, the aspect concerning bass distortion (mechanical noises?) creeping in at less than prodigious SPL's isn't about subjectivity (apart from the fact that it mayn't be an issue to some listeners who only listens at more moderate SPL's), but rather a serious flaw; from my chair a pair of floor standing speakers going for $100k/pair this shouldn't be an issue.

As it is I'm sure your example with the Raidho's (and the manufacturer's meddling with the review) is only the tip of the iceberg. I mean, to those who're willing to let that fact simmer a bit it certainly exposes the mechanisms of the industry and its unfortunate entanglement with the reviewing community, with the sad part being that customers - both literally and figuratively - are buying into it all too easily and thus joins the entanglement as well.

 

A new review is up. This time it is another danish speaker Raidho 3.8. They can be yours for around 100.000 $ grand I must admit that I was not overly impressed with the sound, especially the price considered, so most of my review/opinion had to be uhm, how to put it, be diminished or toned down, as Raidho would not accept my criticism.

As I'm a totally independent with no money involved, so I feel that I can spill my beans elsewhere, but on the youtube channel. So what do I think of Raidho 3.8?

First, I don't think that there are any bad sounding speakers per se at 100.000 $, at least I hope that's not the case. On the other hand, I do think that there is plenty of mediocre speakers at all price points, also at a 100 grand and above.

The tonality of the 3.8 is a variation over the common "happy smile" frequency response. Raidho is probably trying to aim at the +middle aged well heeled audiophile, that often has a recessed top end hearing. Along with the lifted bass response, that does not go down that low, I think it is fair to say, that they sound a bit colored.
The Raidho had a wide soundstage, but lacked some image pinpoint focus, between the speakers. A big let down, for me, was that the bass drivers distorted, when pushed a little. It was by no means at high SPL, probably around 95 dB in the listening chair. No louder than I could have a "normal" conversation, while playing music. That was a big "turn off" for me. In the end the Raidho did not "encourage" me to put on more music, so that's that!
View attachment 124467

Schlager, thanks for the report on these speakers. I'm curious which environment you measured the speakers in? I am quite familiar with these speakers and others in their line and while they are not my preferred choice I have not found the ribbon tweeters to be rolled off above10,000 cycles. They are however extremely sensitive to placement, easily exciting bass room modes and also can be overly ripe in the bass unless they are in the exact right spot. I will say Raidho needs to redesign the footers which do not level well at all which can lead to poor measurement out of the ribbon tweeters if not properly aligned in the vertical axis.

 

Interesting, thanks for sharing.
What was the amplification used, perhaps that’s the problem? Also, the room, etc. Is that response done in room?
The reason I often don’t listen to components before buying them is it’s so hard to judge if they are not in your room and with your components. For example, one could reduce the bass hump with room treatment. Pinpoint focus can be achieved with proper setup of the speakers, room treatment (makes a big difference in this regard!), listening position, and even changing a cable or adding vibration isolation under components.
It’s crazy how everything makes a difference!

Did you look at measurement graph that was shown?
The poor frequency response cannot be remedied by any amps. It would need to be equalized by a component person. If the anechoic response is whacky, it will be so no matter the amps and room treatment. This needs to be right before getting great sound.

 

. If the anechoic response is whacky, it will be so no matter the amps and room treatment. .

Was this measurement taken by you or provided by manufacturer?