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.

 

Bjorn, in the scheme of the "High End Audiophile" world, we "know" that price and quality are linked together, so 30.000 grand probably won't make it. Some people (audiophiles) love to belong to a "special" group and in their mind, purchasing a top dollar system elevates them to a position above the rest of us Joking aside, I believe you actually get some "real estate" for your money's worth. Just to be clear, I'm not affiliated with Stage Accompany or any other player on the audio market.

Nice horns by the way

 

Probably have to price it super high to be considered high-end. That's unfortunately how many audiophiles think. I'm continually surprised by the fact that when going to hifi shows with very poor or mediocre sound from extremely expensive systems, still it seems many are convinced about good sound based on price, looks and bias. You start to wonder how many are actually using their ears or what kind of references people have.

The Stage ribbons are very nice BTW. I'm working on a speaker with a tall ribbon/planar as well.

 

You start to wonder how many are actually using their ears or what kind of references people have.

I think the reality is that audiophiles in general, seldom "trust their ears". When it's suggested that they do ears only auditions (blind test), they find countless excuses for not doing so. That has always been a conundrum to me.

 

I think the reality is that audiophiles in general, seldom "trust their ears". When it's suggested that they do ears only auditions (blind test), they find countless excuses for not doing so. That has always been a conundrum to me.

I think it's the exact opposite with many seeing no value in measurements and don't believe in DBT's because they absolutely do trust their ears and feel it's pointless. As in don't need too. "I know what I hear"

I don't think you can pigeonhole the whole group as I see what we both stated as extreme positions.

It's obvious both measurements and preference are equally important. I think most recognize both are important and more a situation of assigning the amount of priority given to each.

Sounds like a pole!

Rob

 

Sure Rob, I'm just generalizing to make a point (and maybe be a bit polemic), the subject of "just using your ears" vs "measurements" is of course a bit more nuanced. But I will say that it is quite uninteresting from an objective point of view, what a random person thinks about an amplifier, speaker or other component in isolation, as the biased meat calculator under the bonnet always will destroy the quality of all objective assessments, based on other factors than pure sound quality. It immediately becomes more interesting, when components are compared directly with other options back and forth, and even more interesting, when no one has a clue as to which components are actually playing at a given moment. Only then will you know whether it is bias or ears, which constitute the biggest explanation for the differences you hear. For my part I use changes in frequency and time domain to tune my sound, not component bingo and the infamous "synergy matching", I only need synergy in my horns.

Measurement will take me roughly 85 % of the way, but in the time domain (FIR) I find it difficult to evaluate the sound, comparing 2 different settings and corresponding measurements. In that situation I need to listen for center image stability, transparency, overall dryness in the sound (direct sound vs reflections), bass slam and tightness. These attributes are linked to the time domain and how much of the impulse response that is corrected for and this is very much room dependent and to some degree subjective, oops I said it In two different filters I can have two EQ profiles that are almost exactly the same, but the differences in the time domain makes them easy to distinguish between. Which one is correct? Here I have to resort to using my ears and what I find is best.

 

Do audiophiles actually prefer a linear frequency response? I'm not so sure! The reason I ask is because I had a recent experience, where I was invited to a hifi meeting, where DSP would be demonstrated. The system was Focal Alto Utopia BE speakers, McIntosh C2300 Tube preamplifier, McIntosh MC312 power amp, McIntosh MCD600 cd player and a Michell GyroDec turntable, so a pretty costly hifi system.

We took some nearfield measurements of the speaker aprox. 120 cm (48") from the speaker on and off-axis. Unfortunately I did not take a screenshot of them, but I found a measurement of the bigger brother from the same family line; Focal Nova Utopia BE which resemble well from my recollection. A BBC dip a 3 khz followed by a raise in the FR. The dip can give the impression of more depth behind the speakers and the following raise will give an impression of more detail.



Two participants of the meeting preferred the non eq version and one of them, was a former renowned reviewer for the Danish version of High Fidelity magazine. The other guy was smiling when the non eq version played and said "this is how it should sound". He later told us that he played on Wilson Sasha W/P speakers and they look somehow similar in the FR. What a coincidence


Wilson Sasha W/P

Overall to my ears, this system was decent but still lacking in transparency, dynamics, imaging ect. This was specially true playing from the turntable. But then again, this was a living room not optimized for hifi and with a big coffee table between the speakers and listening positions.

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If you took measurements at 48cm but were listening behind the coffee table then there could be other things going on (including compensations to the dip you mention) which could explain the preference for EQ vs non EQ.

 

Hopkins it was 48 inches (120 cm) from the speakers and it was the non eq version that some preferred. In general we hear the direct and reflected sound as a lumped total sound (soundpower), so the dip would be there in all horizontal off axis directions and be prominent in the listening position, with or without the coffee table. I think the biggest impact of the coffee table would be in a skewed and not so stable image.

 

Sorry for the mistake and thanks for the clarification.

 

Those on axis Frequency Response plots are of limited use. There is not a direct correlation between what you hear in room vs a tiny slice of the entire response. You can't predict the in-room balance looking at just the on-axis.

On axis vs in room 1/6 octave averaged same speaker.

Rob

 

Rob, those measurements are taken from Stereophiles webpage.

"Fig.2 Focal-JMlab Nova Utopia Be, quasi-anechoic response on tweeter axis at 36", averaged across 30 degrees horizontal window and corrected for microphone response, with the nearfield responses of the midrange unit (blue), woofer (red), and port (green), and their complex sum (black), taking into account acoustic phase and distance from the nominal farfield point, plotted below 300Hz, 450Hz, 650Hz, and 360Hz, respectively."

I believe you have too much spare time

 

I got the measurements taken of the Focal Alto Utopia BE speakers.
Here on-axis and off-axis.


And here an average

 

Looks to be a measurement fault. Very low level above 10 kHz which I doubt is correct.

 

Bjorn, I have talked to my friend who did the measurements, he will have a look at it. He mentioned something about the impulse response perhaps not being aligned properly. He uses Groundsound software, so it's a bit different than REW that I'm used to.

 

Did he measure the speakers together instead of separately?

 

No, the measurements were taken properly, only one speaker was measured, I myself moved the mic, but the analysis in the software might have gone wrong. Hopefully we will get to the bottom of this, there is enough misinformation in this hobby as it is

 

For what it is worth, my friend sended me these "updated" measurements.

1 m response


Listening position

 

Strange drop in the treble in the listening position. Above 12 kHz there's almost no level. Doesn't make sense and seems to be a measuring issue.

 

For what it is worth, my friend sended me these "updated" measurements.

1 m response
View attachment 119882

Listening position

View attachment 119883

How can that be??? 20 db down at the listening position on the high end??? I can see several db but not that much. Looks like a hinge point at 500Hz??

Rob

 

I agree Rob, it looks a bit strange, but my overall point here is the classic BBC dip in the 2-3 KHz, that some seem to prefer. At least 2 persons attending the hifi meeting preferred the non-eq version (#246). Probably of no surprise, I did not.