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.

 

I do not consider myself an audiophile per se, as I find that angle of the hobby to be bended towards the hardware gear and on visual aesthetics. For me, personally, the hifi system is just a mean to an end, to enjoy the music that I cherish. Through the years I have been to quite some hifi shows, the biggest would be High End Munich Messe. I don’t expect upper echelon sound quality and nor have I heard it, at such shows. There are some good system setups, but they never seem to tick all of the boxes, that I know is achievable.

For me, most audiophiles are willing to live with too many compromises, sound wise, especially in the bass department, which often lacks capacity and most of all evenness, free from resonances and ringing. In that area, I don't sell myself short. I want to be able to play any kind of music, without “restrictions” or shortcomings, while retaining the dynamic aspect that makes music come to life.

Building your own loudspeakers seems, for me, the only logical way, if you want to reach the pinnacle of audio reproduction, compared to commercial solutions. Building speakers is time consuming and with high wages for production and a markup of 10 times or more, you are quickly looking at a price tag only the well-heeled can afford. I know that it is almost impossible to reach the same finish quality as a commercial loudspeaker, but I’m more than willing to sacrifice looks for sound.

 

The internet has made it a whole lot funnier to be in this hobby. The possibility to reach out and get in touch with fellow audiophiles and music lovers has brought many good experiences. Even if I had some personal reservations or plainly didn’t like the sound of a particularly system, it has always been fun to meet other people to listen, learn and have a chat and discussing various approaches and preferences.

One thing I have noticed out through the years in this hobby is that the “take it by ear” approach gives very different sound results, according to how the owners taste and preferences are. Our ears are prone to relative quickly adapt to a certain sound, correct or not. Therefore, without really knowing what is going on, with the sound in the room, we run into problems of pin pointing shortcomings and then do something about them.

Not being able to adjust the frequency response is just one the disadvantages. Removing the passive filter is often like removing a veil from the music and give more clarity. In addition, it gives the opportunity to time align the drivers in the right way, which provides better dynamics. The bass can be adjusted to the room, the crossover solution between the drivers can be improved and in addition, you have far more options in choosing speaker drivers.

 

Speakers in a room is typically a roll of the dice. Many audiophiles have the financial scars to prove it. Listening to speakers at the dealer and then in our own rooms, can come as a shock. It will often be two very different experiences. The room impact on the sound quality will over shade the generic quality of the speakers, unless accounted for. What strikes me is that I sometimes get the feeling that some audiophiles think that they can buy their way around the problems by investing in expensive equipment. Nevertheless, even expensive speakers are subject to the law of physics. I wonder if potential buyers in that market are aware of room interactions?

Which brings me to another point, which is that ’objectivists’ are jealous because we can’t afford expensive equipment or that our systems are not expensive enough to resolve the differences, that people with expensive equipment hear. I regard products dis-passionately; I rather ask ‘what is it, what is its nature’. It seems obvious that expensive audio equipment falls into the luxury goods category. They can have good measurements and be nicely packaged but not necessary audibly better. You could argue that expensive audio equipment give enjoyment of ownership, are build to last or provide better service, but I don't find that as a given. In the end, it really is important to learn to distinguish between actual measured performance and marketing blurb and bragging rights.

 

Often the main speakers will be positioned into the room approximately 0.5-1 meter from the front and sidewalls. Normal cone and dome speakers suffer in sound quality, if placed too close to nearby walls, because most of them lack dispersion/directivity control. The consequence is a whole range of unfortunate reflections, which are not frequency linear and arriving to soon after the direct sound, coloring the total sound power, smearing out transients and blurring imaging. Pulling the speakers away from the surrounding walls, will give a higher ratio of direct sound, but this still doesn’t solve the aforementioned problem, it only diminish it a bit.

All these issues brings in another problem, down the road. Folks with traditional speakers (cones and domes) are forced to place their bass sources where the midrange and tweeter will sound best i.e. out in the room away from walls. This creates speaker boundary interference response (SBIR) which is often seen in measurements as suck outs below 400 Hz. This often leaves the sound lean and fatigue in the upper bass and lower midrange. This is where most instruments and voices have their fundamentals.

I have personally measured and listened to Magico Q7 speakers, driven by D'Agostino Momentum Mono Amps in a private setup. The bass response had a big suck out at 60 Hz plus other dips in the upper bass, due to room interaction. This is a big expensive speaker with 2 x 12” bass woofers in each speaker. Luckily, this guy was pretty relaxed about the whole situation and did not mind take advice from others. The solution was to implement to 21” subwoofers placed diagonally in the room.

You mustn’t think that because you spend a fortune on gear that you are immune to physics.

 

Some extremely expensive commercial loudspeakers are not bad products by objective criteria, if price-performance ratio is not taken into account. They are luxury items, with their price tag completely detached from their performance as a loudspeaker, which is fine. There is a place for that and within the realms of hifi jewelry, some of these companies still seems to care about good engineering, which is nice and unfortunately not a given. One company that comes to mind could be Magico. A couple of years ago they put their new flagship speaker M9 on the market.

Not many reviews have been made of that speaker, probably because of its bulky size. People that have reviewed them all seem to suggest that this is something special, almost a paradigm shift. But wait, I think that I have heard that before, as in almost every time, some company sets assail a new topnotch expensive hifi jewelry on the market.

Some of those reviewers are recognized and well regarded, within the audio community, that is, and has probably been around the block once or twice. However, to me they often come out, as if they clearly don’t have much experience with top-notch DIY setups. Of course, reviewers have to put an angle to the product and praise it, so potential customers gain or retain the interest. But this is a clear indication, to me, that most audiophiles haven’t heard was is actually possible if you go all in, in a no compromise DIY setup.

Some have got out of the "trial-and-error pit" and endlessly component changes, while hoping to strike some luck of synergy. Instead they spent time reading what the really serious people in the industry have found out and then ended up with relatively non-commercial equipment, may indicate that they have discovered something that really pays off in the grand scheme of things of audio.

Typically, those same people also use DSP to keep track of everything, preferably set up with the help of a professional vendor with experience and a scientific approach. They find they also have significantly more control over what is going on in the setup, than what they had when they once experimented with cable changes and magical tweaks a-la such things as, for example, 6-moons love to present as almost brilliant investments.

And when you have come this far, how much do you care about testing gadgets, and then write supposedly generally valid subjective descriptions in a flowery language?

Should they still fall for the temptation and suddenly find themselves in the middle of a test of a new super tube amplifier, then they get the feeling that the language of flower poetry has no function, because first of all, it only describes one very specific situation and because what you really want to, is describing what the amplifier actually does.

But none of the readers really care about that. Strictly speaking, they only want confirmation that the amplifier they are considering has the right street cred, and we have all seen how poorly suited Amir's tests are to convey street cred.

So, maybe when these recognized, if not always liked, serious writers grows up, and we have no guarantee that that will happen, they will exchange flowery language for DSP and start listening to music too.

I think it's time to get real here and realize that in this industry there is no particularly link between well-known and serious.

To the reviewer’s defense, dealing with component replacement is a different way of dealing with hifi, than dealing with neutral electronics/dsp/tailored speakers. It would be impractical for a component-swapping reviewer to have such a tailored and fine-tuned setup. At best, he would have tested neutral amplifiers and DACs against each other, but if they sound the same, it would certainly be a boring reading. So basically reviewers engage in another discipline which not necessarily correlates with "the most credible reproduction of the music".

I don't mean that writers can't get good sound, but that when you have to deal with a lot of component switching, it sets some limits for what type of system is practical.

The reason for the skepticism/criticism I’m directing toward reviewers and their followers as a whole, is that you are constantly faced with the fact that science somehow only "thinks it knows", while those who really “know” are those who do or read a lot of tests. It's like a clique of a special elite group, for those who have “got a clue” about hifi. After all, “that is the way it is, and not what stupid science imagines”.

In the end those who think it's fun to “listen to their system” probably don't prefer the transparent variety.

I feel like I'm balancing on a knife's edge between making a point and offending someone. But then maybe the evening will be a little less boring

 

Just have at least 2 systems a review system and one tailored to your preferences.

Rob

 

Just have at least 2 systems a review system and one tailored to your preferences.

You would need the double real estate for audio unless you push 2 systems in one room. But I'm about to do exactly that. But the approach to each system will not differ, as I'm not a hifi reviewer. I find most of them having the "good old classic" hifi approach and that, to me, that has very little to do with high-end sound.

 

You would need the double real estate for audio unless you push 2 systems in one room. But I'm about to do exactly that. But the approach to each system will not differ, as I'm not a hifi reviewer. I find most of them having the "good old classic" hifi approach and that, to me, that has very little to do with high-end sound.

Hello schlager

What's wrong with "good old classic" HI Fi approach?? Everyone seems to forget High Fidelity means faithfulness to the source material. People were setting up outstanding systems long before DSP was available.

Back when it was all analog some systems could stun you and many still do. The basic premise of good acoustics, proper speaker placement, low distortion and adequate bandwidth are the foundation with systems today just as they were in the past.

Sure you may have better and more accessible tools but the basics from the 50's have not changed.

As far as having 2 systems I would expect them to sound similar in many aspects but never exactly the same. What's the fun in everything sounding the same?? One of the best things in this hobby is there are no absolutes and every system has "wiggle room"

We are never going to match a live performance. It's fun trying to get there and that's the point!

Rob

 

People were setting up outstanding systems long before DSP was available.

I have touched that point somewhere in this thread. I think we are talking of different degrees of "how good". I have also pointed out from time to time, that you can have good sound without the use of DSP, I have heard it myself, but there is more to it, for me.

We are never going to match a live performance. It's fun trying to get there and that's the point!

Agreed, but I believe with a high-end sounding system, we can come pretty close and the road, to get there, seems to be quite narrow. So in my experience, not many systems can get the honor of being truly high-end sounding. I have a whole list of criteria, that I find essential, if the goal is high-end sound. I'll probably get to that at some point.

 

Like you, my system is fully DSPed. I think the biggest revolution in the past 10-15 years is the tools that were available to professionals has filtered down to hobbyists like us. Software programs are available, some are even free (like REW). All that is required is to get an inexpensive microphone, get some software, and learn (arguably the hardest part). Every week, refinements in the way I implement my DSP bring improvements I could only dream about before.

 

Yes, I believe one of the biggest "mountains to climb" is the willingness to learn how to use all these tools at our disposal. Another "obstacle" is hifi traditions and "romantic" ideas on how things should be done, because that is what has been done for decades. We often hear about this "pure virgin signal", that is not to be molested. It is a funny way of thinking, the signal is totally molested (distorted) ones it reach our ears in the listening position. What clever DSP is doing is in fact restoring this distorted signal, to be as close as the original input signal as possible, in the given situation.

 

Yes, I believe one of the biggest "mountains to climb" is the willingness to learn how to use all these tools at our disposal. Another "obstacle" is hifi traditions and "romantic" ideas on how things should be done, because that is what has been done for decades. We often hear about this "pure virgin signal", that is not to be molested. It is a funny way of thinking, the signal is totally molested (distorted) ones it reach our ears in the listening position. What clever DSP is doing is in fact restoring this distorted signal, to be as close as the original input signal as possible, in the given situation.

What clever DSP is doing is not restoring a distorted signal but compensating for the deficiencies of a given loudspeaker or set of loudspeakers.

Your assumption that DSP is "harmless" is based on the idea that digital conversion steps are totally transparent, which is in fact only a hypothesis based on:

- assumptions that levels of distortion measured with simple test tones and a limited set of indicators reflect the behavior of equipment with more complex signals (which cannot be measured)

- circumstancial evidence that passing a signal repeatedly through ADC and DAC does not alter the results. This assumes that distortion would be "cumulative" while in fact this is not necessarily the case (random jitter or glitched being an example) and it also assumes that the amplification or speakers used to perform these tests are not going to mask any level of distortion of the conversion process.

There are indeed several "camps" in audio, and I am not sure which one is doing the "magical thinking". At the end of the day, it all comes down to listening, and here our experience is also limited, conditioned by the components used, and we all have our preferences or sensitivity (towards certain types of distortion).

 

hopkins, I don't agree with much of the above you said.

"Clever" DSP is much more than PEQ's and also takes the room and human psycho-acoustics into the equation. It's beyond the scope, for now, to dig deeper. Just look at an impulse response before and after DRC. Then you will see that the signal was indeed restored, also in the listening position.

The almost perfect IR (blue) shows that both frequency and time domain was restored.


A test you can do on AD-DA is, to connect an AD and DA one after the other and compare this with a cable. Some combinations are almost completely impossible to separate from a cable, while others are easy to separate from a cable.

This is how Topping D90 is measuring on the most advanced measuring rigg. I can assure you that it will be completely transparent, to the human ear.


In a DSP unit with ADC and DAC, all the digital components inside the product are synchronous, that is, they do not make timing errors. For a DSP with digital input, which I have, what comes out of the DSP will be bit perfect and reclocked. If it is fed via some variant of I2S, it is mathematically perfect and without possibilities for analogue errors such as jitter, and also without possibilities for bit errors.

I don't prefer any type of distortions, that is the whole point. I'm not discussing My-fi but Hi-fi as in high fidelity. It is about getting the output signal as close to the input signal, as possible and preferable in the LP. Adding distortion, does not help, how could it?

Maybe it comes down to that people really don't like the sound of their speakers, when they use transparent gear.

 

- assumptions that levels of distortion measured with simple test tones and a limited set of indicators reflect the behavior of equipment with more complex signals (which cannot be measured)

Sorry to be blunt, but it appears reasonably ignorant and a bit arrogant to reject engineering since 1928. These things are very well understood. But perhaps, that is where the magic comes in. 19 + 20 kHz intermodulation distortion is one of the hardest ways to test a component. This test can say more about how something sounds than, for example, the usual distortion spectrum at 1 kHz. What usually happens is that power amplifiers and other hi-fi electronics get less loop gain (NFB) at high frequencies, so IMD would be audible.

 

In a DSP unit with ADC and DAC, all the digital components inside the product are synchronous, that is, they do not make timing errors. For a DSP with digital input, which I have, what comes out of the DSP will be bit perfect and reclocked. If it is fed via some variant of I2S, it is mathematically perfect and without possibilities for analogue errors such as jitter, and also without possibilities for bit errors.

Sorry to be blunt but this is also fairly ignorant and a bit arrogant

I don't think we need to continue this exchange.it has all been debated before.

Your project is interesting. Your "balancing act", as you mentioned above, is not really required and doing you a service.

 

Choosing a loudspeaker may be the biggest challenge for an audiophile. There are countless brands from which to choose, all with their particular angle of what design is best. Almost none of them shows measurements to back up claims.

Since the room has such a profound impact on the sound of a loudspeaker and it is impossible to listen in a blind test at an audio store, there is little that an audiophile can do to make a rational decision. Fortunately, science has come to the rescue with a set of measurements, that have been proven to demonstrate an extremely close correlation with sound quality, as based on carefully controlled double-blind listening tests. This group of measurements have been adopted as the industry standard for measuring loudspeakers.

https://shop.cta.tech/products/standard-method-of-measurement-for-in-home-loudspeakers.

Contradicting the often repeated claim that choosing a loudspeaker is a very personal choice, research has proven that regardless of age, culture, or listening experience, all people with normal hearing generally agree on which speakers sound better than others. Indeed, there is a universal definition of what sounds good.

AES E-Library » A Multiple Regression Model for Predicting Loudspeaker Preference Using Objective Measurements: Part I - Listening Test Results

Part I of this paper presents the objective measurements and listening test results on 13 loudspeakers rated according to preference, spectral balance and distortion. In part II the data provides the framework for the development and verification of a multiple regression model that predicts...

www.aes.org

https://secure.aes.org/forum/pubs/co...ns/?elib=12847

At the same time, it is a hobby that can be enjoyed in different ways. And for some, the goal is perhaps sometimes the way, i.e. that the joy of testing a new amplifier or new damping feet or whatever it might be, is perhaps more fun than getting good sound with something as "boring" as a DSP. And that is totally okay.

 

Thanks for this. Some of the links are not working. Can you fix them?

 

Just to drive home the point of how much the room influences the sound, this image was posted on another forum:



In red, Monitor Audio MA-8 Silver. In green, Yamaha NS-1000m. The question was, "why do these two different speakers have almost the same in-room frequency response?". If you look between 40Hz - 400Hz, you can see the peaks and troughs match each other almost exactly. Only above 400Hz do the curves start to diverge.

Just by looking at this graph, I can calculate the approximate volume of his listening room. And maybe get reasonably close to the actual dimensions by making some educated guesses.

Anybody want to guess at the answer? (Not you schlager, you probably know the answer).

 

Extrapolation of room modes, but don't know the formulas.

 

~10x18?