Introduction of Vera Audio Coherence 12 - a high quality speaker many can afford

[Bjorn]

Want to introduce the Vera Audio Coherence 12 speaker to the ASR community. A speaker that we're getting quite close to release.

The picture here is of a prototype. The final model will have a new and better looking platform. Disregard the plywood panel underneath the speaker here. The speaker will come with feet that is tailored to minimize resonances.

This is an active design with the choice of either built in Hypex FA252 or sold with an external crossover as miniDSP Flex (various options), Danville dspNexus. DEQX is also possible. 4-channel amplification is needed when choosing an external crossover and this can be chosen freely by the customer, but the gain should be equal.


Prices for a pair are rough estimates and may change.
1. Estimated price with a balanced 4-channel miniDSP Flex: Below $5300 ex VAT and shipping

2. Estimated price with built in Hypex FA252 amp: Below $6200 ex VAT and shipping

Will get into the design in the coming posts.

 

[DanielT]

Good luck with the marketing and sales. They look nice and cool. I like the style with that width of baffle with round baffle corners. Most likely good for the sound but in addition it looks nice. Black piano lacquer, nice.

I suspect you were experimenting with the length of planar tweeters in them? How did it become the planar tweeters that are in them?

Please let us know if you will bring them to a HiFi fair in Norway or Sweden. It would be fun and interesting to see and hear them IRL (although the acoustics in such demo rooms can be pretty crappy).

 

[holdingpants01]

Looks cool! Are those prices for a single speaker or a pair?

 

[Bjorn]

Good luck with the marketing and sales. They look nice and cool. I like the style with that width of baffle with round baffle corners. Most likely good for the sound but in addition it looks nice. Black piano lacquer, nice.

I suspect you were experimenting with the length of planar tweeters in them? How did it become the planar tweeters that are in them?

Please let us know if you will bring them to a HiFi fair in Norway or Sweden. It would be fun and interesting to see and hear them IRL (although the acoustics in such demo rooms can be pretty crappy).

Thank you. Next prototype will have a veneer top. We'll see how that looks, but all piano black will for sure be an option.

I'll get into driver details later.

May bring them to the hifi show in Asker outside Oslo in March.

OSLO HIFI SHOW | Oslo HiFi Show

www.oslohifishow.no

I don't know when the next hifi fairs are in Sweden, but we might only prioritize max 1-2 events each year and have to choose these carefully. This is one way of keeping the cost down and lower sales price to customers. Marketing, and including many hifi events, can be very expensive and it's customer who eventually pays for this.

 

[Bjorn]

Looks cool! Are those prices for a single speaker or a pair?

For a pair for sure. Apologize, should have included that right away and have updated the first post with the prices for a pair. Buying a single one is of course possible if anyone wants to use one as a center speaker behind a sound trasparent screen.

 

[GXAlan]

Magnetic grilles? Maximum SPL?

 

[GXAlan]

For a pair for sure. Apologize, should have included that right away and have updated the first post with the prices for a pair.

That’s a good sign when the asking price could be per speaker but also per pair

 

[miero]

What rule was used to determine a distance between tweeter and midwoofer? Is this distance accounted in the crossover?

 

[Matt_Holland]

What rule was used to determine a distance between tweeter and midwoofer? Is this distance accounted in the crossover?

Based on driver separation and woofer size I would guess at a crossover of no higher than 400Hz. I assume the smaller driver is full-range?

 

[Soniclife]

They look great. Are they a 2 way? And as this is ASR, show us the measurements.

 

[TimW]

I'm sorry but all I can see mounted to the cabinet is a subwoofer driver and a planar tweeter. Am I missing something?

 

[Bjorn]

Questions will be answered along the way.

General goals of the design

- From the very start of the design, a coherent sound stage was a requirement. Based on experience and testing, getting the crossover far away from the sensitive area is important for a speaker to sound more like real instrument and voices. For a speaker of this type, this meant either using one driver that could cover a large frequency area or a coax. A large amount of drivers have been tested, which I will get into later.

- Coherency, among other features, required an active design. So a passive speaker was never considered. Going active means drivers can be perfectly time aligned, so they arrive at listener’s ear simultaneously. Active also opens the door for other benefits.

- Having directivity control was another primary goal. A uniform directivity in the most sensitive area is important for a correct tonality, especially when room treatment is sparse. With a uniform directivity, the reflected energy from the room will to a much greater degree resemble the direct signal.

- However, a uniform directivity doesn’t alone mean that a speaker will yield an even response when actually placed in a living room. What good is it if the speakers only measures well anechoic. So another important design goal was to have a speaker that actually measured very even when placed in living rooms.

- The speaker needed to be engaging to listen to. Large speakers with bigger drivers can simply do things smaller cannot. The combination of a low baffle step where more sound is being send forward towards the listener with a good size woofer lay the ground for this.

 

[Bjorn]

Sensitivity and SPL

The sensitivity of the speaker is around 95 dB.

As I'm sure many of you know SPL will vary with frequency. So rating the speaker with a certain SPL can be misleading.
But the speaker can play loud, and especially at the important midbass area where often the highest SPL is needed. Here one speaker can reach above 120 dB at 1 m at peaks.

Every speaker will drop SPL at the lowest frequencies. However it reaches high SPL in the subwoofer frequencies too. About 113 dB without room gain from walls at 30 Hz from one speaker. With the second speaker and possible room gain, level can easily exceed 120 dB. Will need a serious subwoofer or several to keep up with it! So adding something like one 15" subwoofer in a large bass reflex would actually minimize the total SPL in the subwoofer range.

 

[sigbergaudio]

Is the bottom driver a 12"? And is the cabinet ported?

 

[Matt_Holland]

For a speaker of this type, this meant either using one driver that could cover a large frequency area or a coax. A large amount of drivers have been tested, which I will get into later.

I’m impatient. Please tell us about the drivers ASAP. It’s the obvious curiosity here because of the large spacing between woofer and mid-high.

 

[Sokel]

Based on driver separation and woofer size I would guess at a crossover of no higher than 400Hz. I assume the smaller driver is full-range?

More like about 200-250Hz with the 1/4 rule if I get the size right .

 

[Sokel]

More like about 200-250Hz with the 1/4 rule if I get the size right .

Scrap that,if by the looks the ribbon is an LM8K,it can't be lower than 500Hz.
I wonder if there's a passive correction network for up-high except for the active one.

 

[DanielT]

More like about 200-250Hz with the 1/4 rule if I get the size right .

1/4 rule, which at the crossover point at around 2.5-5kHz with a bass driver of 4-8 inches and a 1 inch tweeter can be very difficult to put into practice. Solution for that addresses the creator of VituixCAD Kimmosto who says can be that:

Minimum c-c is 1.0 x wave length and maximum about 1.4 x wave length at XO frequency assuming that design is conventional uni-directional box (not open baffle) with phase matching (acoustical 4th order) slopes. Good and quite flexible initial/design value for c-c is 1.2 x wave length at XO, giving smooth combination of power and early reflections i.e. balanced sound without significant power dip at XO due to bump in DI and dip in vertical early reflections. In other words, this concept aims lobe nulls to directions which are the least significant for power response and vertical early reflections - and listener sitting in sweet spot of course.

VituixCAD thread on diyaudio contains three examples with real life data and simplified theoretical study about c-c = 1.2 x wave length concept. It's actually quite common in practice. Traditionally XO frequencies 2.5-5 kHz were common, and sound of those speakers was typically smoother and more tolerable than (modern) low XO point. So I'm not trying to invent anything new or provoke. Just giving an answer why some sound features were better in the past; no blood from ears while listening 80s' Gary Moore or Iron Maiden.
Common (modern) opinion/statement is that c-c should be as short as possible. With "normal luck" it hits c-c = 1/2 wave length at XO which causes the worst possible power dip and balance break with conventional unidirectional box speaker. Also risk of power bump above XO point increases with conventional tweeters without wave guide. c-c = 1/4 wave length at XO is just an utopia - worthless to mention for other than XO between mid and woofer, or woofer and small full-range as a tweeter.

Quote from #2 and #9 in this thread:

Some help with lobing

I think I understand the concept but can't figure out the solution. "Lobing occurs with any two drivers producing the same frequency range in parallel (identical signal) where the distance between the drivers is greater than 1/4 wavelength of any frequency they are reproducing." So if I am...

audiosciencereview.com

VituixCAD Loudspeaker simulator

 

[Sokel]

1/4 rule, which at the crossover point at around 2.5-5kHz with a bass driver of 4-8 inches and a 1 inch tweeter can be very difficult to put into practice. Solution for that addresses the creator of VituixCAD Kimmosto who says can be that:

Minimum c-c is 1.0 x wave length and maximum about 1.4 x wave length at XO frequency assuming that design is conventional uni-directional box (not open baffle) with phase matching (acoustical 4th order) slopes. Good and quite flexible initial/design value for c-c is 1.2 x wave length at XO, giving smooth combination of power and early reflections i.e. balanced sound without significant power dip at XO due to bump in DI and dip in vertical early reflections. In other words, this concept aims lobe nulls to directions which are the least significant for power response and vertical early reflections - and listener sitting in sweet spot of course.

VituixCAD thread on diyaudio contains three examples with real life data and simplified theoretical study about c-c = 1.2 x wave length concept. It's actually quite common in practice. Traditionally XO frequencies 2.5-5 kHz were common, and sound of those speakers was typically smoother and more tolerable than (modern) low XO point. So I'm not trying to invent anything new or provoke. Just giving an answer why some sound features were better in the past; no blood from ears while listening 80s' Gary Moore or Iron Maiden.
Common (modern) opinion/statement is that c-c should be as short as possible. With "normal luck" it hits c-c = 1/2 wave length at XO which causes the worst possible power dip and balance break with conventional unidirectional box speaker. Also risk of power bump above XO point increases with conventional tweeters without wave guide. c-c = 1/4 wave length at XO is just an utopia - worthless to mention for other than XO between mid and woofer, or woofer and small full-range as a tweeter.

Quote from #2 and #9 in this thread:

Some help with lobing

I think I understand the concept but can't figure out the solution. "Lobing occurs with any two drivers producing the same frequency range in parallel (identical signal) where the distance between the drivers is greater than 1/4 wavelength of any frequency they are reproducing." So if I am...

audiosciencereview.com

VituixCAD Loudspeaker simulator

That's a 2-way speaker so the x-over is between mid (let's say it that way) and woofer.
It falls under the last sentence of Kimmosto and it's pretty common.

 

[DanielT]

That's a 2-way speaker so the x-over is between mid (let's say it that way) and woofer.
It falls under the last sentence of Kimmosto and it's pretty common.

But is it the distance between the planar tweeter and the bass driver you see in the picture of Bjorn's speakers we are talking about? I may have missed something.
I thought that was it.

You mention 500 Hz. That doesn't seem to be an impossibly long distance then between then in that case.

If I start from a calculation example that Kimmosto brings up in the thread I referenced but pop in 500 Hz instead:
With sound speed = 344 m/s and XO frequency = 500 Hz, c-c = 1.2 * 344000 / 500= 826 mm.

So 826 mm distance between drivers in that case, given the 4 order crossover.
With the addition that I don't know where to put the c in c-c distance with an oblong planar tweeter.
(probably in the center but still)

In any case, Bjorn can describe the design later.