OP
- Thread Starter
- #101
When gain isn't optimized and is much too high, distortion and incorrect measurements happen. The graph actually becomes flatter and flatter.
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Introduction of Vera Audio Coherence 12 - a high quality speaker many can afford
- Thread starter Bjorn
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Sokel
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I got your post but observing anything higher than 100Hz with 1/3 smoothing is close to useless except if you only want to see a general slope.
That's why we have this 50dB range -1/12 smoothing (at least) "rule" here.
OP
- Thread Starter
- #103
Those graphs have been showed with higher resolution before in this thread. For example one here: https://www.audiosciencereview.com/...ker-many-can-afford.58054/page-5#post-2263391
But lower resolution is also good to show. It does show the overall tonality well and is far from useless IMO. If we were to follow the standard, that's actually 25 dB decadent. Something no one hardly uses and has the tendencey to make most in room graphs look like crap.
Sokel
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To replicate your results, here's the exact same measurement shown as two different ones you posted:
These, are both useless to compare, right one is like this:
That's the one to make some* useful conclusions.
*of course that's not for pro use, people that fixed my room laugh at these kind of measurements. But still useful in a way.
These, are both useless to compare, right one is like this:
That's the one to make some* useful conclusions.
*of course that's not for pro use, people that fixed my room laugh at these kind of measurements. But still useful in a way.
OP
- Thread Starter
- #105
First of all, this is a development thread of the speaker. The overall tuning has been somewhat different. Plus of course it can easily be changed. Secondly, the measurements are from rooms and positions that are challenging. And there's hardly any acoustic treatment. Which is also part of the point, to show a speaker that can measure very eveny in even such space. Obviously a better room and acoustics can make this more even and a different tuning more flat or with less fall towards the treble is that's a desire.
The graph below is from the space in the picture. Not exactly an easy position for a speaker. And the graph is without the subwoofer in use.
The graph below is from the space in the picture. Not exactly an easy position for a speaker. And the graph is without the subwoofer in use.
Sokel
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Vladimir Filevski
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That planar driver is star of the show, obviously - I congratulate you on the right choice. I suppose that driver is made for you on a special order, because I am not aware of such off-the-shelf driver. Widely available GRS/chinese planar drivers are just bad.
Many years ago, I had very good experience with planar mid-high driver Bohlender-Graebener Neo8PDR. I mounted the planar driver on a small open-baffle atop conventional bass-reflex enclosure with ScanSpeak midwoofer. Essentially, it was dipole loudspeaker across wide mid-high frequency range, creating wonderful spaciousness. Did you make experiments with open-baffle arrangements for your planar driver? If not, I am suggesting to try it.
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OP
- Thread Starter
- #108
I have tested them all, including the GRS's and Bohlender-Graebener drivers.
Dipole has been tested as well. Definetly not the way to go if one uses a quality cabinet IMO.
Vladimir Filevski
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Interesting, what were the drawbacks with dipole mounted planar driver?
OP
- Thread Starter
- #110
You loose a lot of level, meaning one has to cross it over much higher. It wouldn't be a "Coherence" speaker anymore
It would render what's been the goal of the speaker design from the start. Low crossover here is key.Sound quality was also very polite and "tame", lacking in dynamics and engangement. The latter might have been better with a large open baffle, but it's not ideal for most room to send just as much energy backwards as forward either. This either requires good distance from the front wall or to absorb it with broadband absorption. With today's baffle, the speaker can be placed close to the front wall and still sound very good with no front wall treatment.
Vladimir Filevski
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OP
- Thread Starter
- #112
The Coherence 12 is in some ways like a full tone electrostatic speaker with great dynamics and low frequency extension. Obviously the dispersion pattern is different, but it has some of those qualities of a very coherent and large sound stage with transparency and high resolution of the vocal range.
Have you said what the crossover point is?
OP
- Thread Starter
- #114
No. Need to come back to that. No one has guessed it correctly by the way.
I wasn't aware we were ment to guess.
400Hz? If it's much higher than that I don't see how you can make it work, but I also doubt the tweeter can go that low. I assume you are using steep slopes.
Sokel
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500Hz was my second guess judging by the drivers used if the ribbon is LM8K (first one was too low, I haven't realized the distance between them)
I'm very curious too!
OP
- Thread Starter
- #117
If anyone is after a special veneer or paint, please contact us. We can do a lot of custom finishes here, but it would needs to be based on a pre-order.
Ebony finish like below is one possibility. We can do glossy veneer as well.
Ebony finish like below is one possibility. We can do glossy veneer as well.
OP
- Thread Starter
- #118
Are speakers with the classic crossover frequency at 1-4 KHz a faulty design?
Almost all speakers on the market have crossover frequencies at 1 KHz or higher. Most often in the 2-4 KHz range. This is also in the most sensitive frequency range for our ears. Two drivers playing in the same range will create what can be defined as superposition. Two sound sources that create interference with each other. Similar to two ripples on a water surface that meet each other.
If the interference is large enough, it will also create frequency deviations or what is called lobing in sound. But even without the lobing effect, there is destructive interference between the drivers that our ears are sensitive to. It primarily affects three areas:
- It sounds more messy, not as precise and creates listening fatigue faster
- It sounds less coherent
- The sound image becomes smaller
Sound from voices and instruments does not have this breakup. With Coherence 12, the crossover frequency is so low that you avoid the problem. The result is something different from traditional speakers. The soundstage is large, coherent and pleasant over time.
When you have become accustomed to this coherency then I would say that yes; The traditional crossover in speakers is largely a misconstruction.
Almost all speakers on the market have crossover frequencies at 1 KHz or higher. Most often in the 2-4 KHz range. This is also in the most sensitive frequency range for our ears. Two drivers playing in the same range will create what can be defined as superposition. Two sound sources that create interference with each other. Similar to two ripples on a water surface that meet each other.
If the interference is large enough, it will also create frequency deviations or what is called lobing in sound. But even without the lobing effect, there is destructive interference between the drivers that our ears are sensitive to. It primarily affects three areas:
- It sounds more messy, not as precise and creates listening fatigue faster
- It sounds less coherent
- The sound image becomes smaller
Sound from voices and instruments does not have this breakup. With Coherence 12, the crossover frequency is so low that you avoid the problem. The result is something different from traditional speakers. The soundstage is large, coherent and pleasant over time.
When you have become accustomed to this coherency then I would say that yes; The traditional crossover in speakers is largely a misconstruction.
OP
- Thread Starter
- #119
Recently, work has been done on the crossover frequency and FIR filters have been experimented with. The experience is that FIR for crossover sounds better than IIR, which also makes sense theoretically. You get linear phase in addition to the direcitvity being more even around the crossover frequency. The latter is possibly the most important.
Audibility of linear phase will depend on the listening room. In a room that is completely untreated acoustically and has a lot of high gain reflections, it will be difficult to hear the difference between a phase that is linear or unlinear. However, with more control over the reflections, phase linearity becomes audible. This was actually discovered during the development of the LEDE principle all the way back to the 70s and 80s. The result was that custom phase linear speakers were designed for certain LEDE rooms since it was so audible.
Audibility of linear phase will depend on the listening room. In a room that is completely untreated acoustically and has a lot of high gain reflections, it will be difficult to hear the difference between a phase that is linear or unlinear. However, with more control over the reflections, phase linearity becomes audible. This was actually discovered during the development of the LEDE principle all the way back to the 70s and 80s. The result was that custom phase linear speakers were designed for certain LEDE rooms since it was so audible.
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