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.

 

Zeotrope, did you watch the video? The measurement shown is from Stereophile and here is the in-room response that Morten took.





The listening room and the Gryphon Diablo amp. The Nuprime Evolution Two mono amps clipped, because of the speakers very difficult load.

 

Jägerst.​

You are asking some relevant questions, but we can only speculate on Raidho's behavior of being afraid of a little negative criticism, when the critique from the majority of the review team is overly positive. I can reveal that Morten pretty much agreed with my critique.

And yes, a speaker at this price point should not give in at semi high SPL, that is a total bummer.

The problematic entanglement of manufacture and reviewer, is old in hifi. Too much money and interests is at stake from both sides. When I approached Morten some time ago, we had a conversation about this problem and he said that I could be quite frank in my reviews. I told him that he couldn't handle the truth and he said "true"

 

gleeds, pls watch the video, it's all in there. Measurement from Stereophile correlates pretty well with the measurements taken by Morten in his EBU certified listening room. As to exciting bass room modes, it is an ever returning problem, when you place a (big) speaker in a room. As such, I don't think that the Raidho is more sensitive to this, than other speakers, as it all comes down to physics.

 

Horizontal response




Vertical response



With the dispersion pattern in combination with the measured frequency response, I think it is fair to say that an objectively more neutral engineered speaker, will sound quite different.

 

In this video from 9:09 Morten talks a bit about room acoustics and how his listening room is build to EBU standards.

 

It's basically a broken frequency response. Needs to be equalized or change the passive crossover for decent sound quality from it.

 

Wow that's what you get for 100K!!! There is no excuse for the FR response or the ridiculously low impedance. From Stereophile :

The electrical phase angle (dotted trace) is occasionally high, especially at low frequencies. The equivalent peak dissipation resistance, or EPDR (footnote 1), lies below 3 ohms between 170Hz and 540Hz and below 2 ohms between 56Hz and 101Hz. The minimum EPDR values are 1.1 ohms at 70Hz and 2.17 ohms at 287Hz. The TD3.8 is a demanding load.

Rob

 

Yep, the Raidho is a tough load, brought the Nuprime Evolution 2 mono amps down to their knees. I find that a major issue with many so-called high end speakers, they are ridiculously hard to drive. From my perspective it just boils down to bad engineering.

 

Have you had a chance to listen to these speakers?

 

Hopkins, no unfortunately not. Morten tried to get a review pair to his home, but Steinway & Lyngdorf refused, as they wanted to control the review setup/session. So Morten apparently got a quick chance for an audition, at a local dealer and only team member Tim got along, damn . But I have enjoyed the review so far, only seen session 1 and 2.

Me and Morten have pretty much agreed in the reviews so far, so I think they are very good speakers. Actually, I have some plans of making my own take on the speaker, I have the parts. The design is a hybrid of open baffle and cardioid, so you need some serious bass power. Instead og 6 x 12" I will use 4 x 15" and then a B&G NEO8S as a fullrange pointsource from 400 hz, should work nicely.

 

Hopkins, no unfortunately not. Morten tried to get a review pair to his home, but Steinway & Lyngdorf refused, as they wanted to control the review setup/session. So Morten apparently got a quick chance for an audition, at a local dealer and only team member Tim got along, damn . But I have enjoyed the review so far, only seen session 1 and 2.

Me and Morten have pretty much agreed in the reviews so far, so I think they are very good speakers. Actually, I have some plans of making my own take on the speaker, I have the parts. The design is a hybrid of open baffle and cardioid, so you need some serious bass power. Instead og 6 x 12" I will use 4 x 15" and then a B&G NEO8S as a fullrange pointsource from 400 hz, should work nicely.

Thanks. I look forward to hearing about your "build"

 

Hopkins, don't hold your breath, lots of projects in the pipeline, but eventually things will happen.

 

Currently I have added some DIY freestanding absorbers on the first reflection points in my living room, so I can hide them when I have visitors.

I am impressed with the "increase" in detail and especially the sharpness of the image / instruments. Only I do notice that some tracks seem less spacious.

Perhaps making some wooden slats on some panels to make a hybrid between diffusion / absorption? I don’t want to diffuse much since I have a small room.

My second question is regarding room acoustics when use a synergy horn. I can imagine that because of the constant directivity there are no timbre accuracy issue’s when ditching some panels, is this correct? Meaning it will only a compromise between imaging and spaciousness, or are there more disadvantages in consideration?

 

Wood slats don't offer proper diffusion and will cause specular energy. If you room is sufficient wide, you could use the RPG Modffractal for the side walls reflections farthers away from each speaker and possibly at other later arrival reflections. These are the best diffusers in the market IMO and I have tried many. You need to consider the time of flight when choosing the right type of treatment.

 

Nicktube, in a small room I would go with absorption over diffusion. You will still have lots of reflected sound with relative high amplitude to the direct sound in a small room, so damping the room seems to work best. I have 0.2-0.3 sec. RT60 time above 500 Hz, which can be considered quite dry, but I like it.

 

Is there a diffuse sound field in a small room? No, and that's the requirement for a RT60 to exist.

 

Well, many still use RT60 for comparison. What about waterfall plot, is that "useless" as well?

 

These are a bit old measurement and more absorption has entered the room since.

Left speaker



Right



Left decay



Right



Are these measurement useless in terms of bringing information of a system/rooms behavior, to the table?

 

Waterfall and reverberation time have nothing to do with each other.

RT60 is the measurement of the decay time of a well mixed reverberant sound field well beyond Dc, a real critical distance.
RT60 is the time in seconds for the reverberant sound field to decay 60 dB after the sound source is silenced.

Since in small rooms, there is no Dc, no well mixed sound field, hence, no reverberation but merely a series of early reflected energy, the measurement of RT60 becomes meaningless in such environments.

What becomes meaningful is the control of early reflections because there is no reverberation to mask them.”

Modal decay rates are not reverberation. Reverberation is “the time in seconds that it takes a diffuse sound field, well beyond a real critical distance, to lower in level by 60 dB when the sound source is silenced.” Modal decay rates are dB-per-second (dB/s) rate of decay for a specific modal frequency.

 

Please don't take this as criticism, but 0.2 -0.3ms is very dry in terms of sound. This is how control rooms are tuned for mastering - you basically only hear direct sound. This is very good for evaluating and tuning the recording.
The rooms where the musicians play have a reverberation time of 0.4 -0.5 ms so that the tones of a piano, for example, can fade out particularly realistically.if you would like to hear as if you were there live my tip.

In the bass below 150hz your room is excellent, I wouldn't change anything there. My tip is to remove some sound-absorbing materials, which also makes a room more like a living room and you feel more comfortable.