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

[Koeitje]

He explained it in one of the previous posts. The low woofer removes the cancellation due to floor bounce. This is typically around 300-600Hz depending on woofer height and listening distance. The aim is to have the higher frequency drivers operating above the frequency at which they would otherwise create a floor bounce cancellation.

I'd like to see the vertical directivity then.

 

[Matt_Holland]

I'd like to see the vertical directivity then.

Me too. I suspect that if the crossover frequency is low enough that there won’t be any significant directivity error.

 

[Mnyb]

Historically hifi magazines always talked about the “sensitive area” around the crossover region at 2/4KHz. I think this is more likely because many speakers failed to create a smooth crossover transition off-axis leading to inconsistent sound quality from room to room, or just in general. The perceived fix to this would to move the crossover point away from this “sensitive” frequency range believing that our hearing is more critical of errors in that range. In reality it’s due to it being harder to achieve off-axis consistency between drivers crossing over at higher frequencies.

+1 before directivity where understood, x over was usually pushed towards to 3-4 k end in some designs as a band aid .

 

[Bjorn]

Why did you choose a lower placed woofer then and up to what frequency does the woofer play?

It avoids the floor bounce and measures more even over a reflective floor.

Here's an average of both types of speakers at 5 different locations. Red is with woofer placed right underneath the top driver and green is with the woofer at the bottom.

Not only have we avoided the detrimental floor bounce between 200-300 Hz, but we also have achieved a more even response in the midrange.

 

[Palmer]

Looks like a winner to me... Off topic, your company offers acoustic panels, at what I think are very competitive prices. Will your products, including this speaker, have representation in the US?

 

[Bjorn]

Looks like a winner to me... Off topic, your company offers acoustic panels, at what I think are very competitive prices. Will your products, including this speaker, have representation in the US?

Our panels are RPG products manufactured in England. While we have some custom acoustic products that I've been involved in developing, most products are possible to order from RPG Acoustics USA. However, I'm not sure they are selling in smaller quantities direct to customers anymore.

Acoustical Products & Superior Sound | RPG Acoustical Systems

RPG Acoustical Systems is a world-class provider of acoustic products with high-performance sound absorption and diffusion qualities.

www.rpgacoustic.com

Most likely we will have representation in Orlando area for our CBT speaker sometime, which is another speaker design we're working on. Picture further below without drivers. But not sure with our Vera Audio Coherence 12 speaker or other Vera Audio products. The drawback of this is a raise in cost. Direct sales keeps prices lower.

 

[Matt_Holland]

View attachment 403507

Good lord, that design needs some explaining

 

[Bjorn]

Good lord, that design needs some explaining

Plenty of that here: https://www.keele-omholt-technologies.com/papers.php

 

[Bjorn]

Back to topic. Let's continue with some indoor-measurements. More measurements will eventually be shared.

Obviously, room modes isn't something that the speake avoids. The room will always dictate the lowest frequencies. Placement, using subwoofer(s), and acoustics treatment and EQ are ways to tackle this. What I will be sharing here is completely without any EQ of peaks and dips and no subwoofer. Sometimes the low frequency response is good, sometimes it isn't great.

In front of large windows in a room with cathedral ceiling. Good distance to both side walls here. Measured over a reflective floor and 1/24 Octave smoothing.

A placement in a narrow space is challenging. And especially with this type of ceiling. Most commercial speakers tested here measured and sounded very poor.

The measurements below of left and right are without the subwoofer FIY.

Left channel with 1/24 octave smoothing:

Right channel, 1/24 octave smoothing:

There are a few bass traps in the corners and two absorbers on each nearest side wall. No other treatment. Right speaker response is a bit rough here, but this is a challenging environment as well.

 

[Matt_Holland]

Back to topic. Let's continue with some indoor-measurements. More measurements will eventually be shared.

Obviously, room modes isn't something that the speake avoids. The room will always dictate the lowest frequencies. Placement, using subwoofer(s), and acoustics treatment and EQ are ways to tackle this. What I will be sharing here is completely without any EQ of peaks and dips and no subwoofer. Sometimes the low frequency response is good, sometimes it isn't great.

In front of large windows in a room with cathedral ceiling. Good distance to both side walls here. Measured over a reflective floor and 1/24 Octave smoothing.
View attachment 403516

A placement in a narrow space is challenging. And especially with this type of ceiling. Most commercial speakers tested here measured and sounded very poor.
View attachment 403521

The measurements below of left and right are without the subwoofer FIY.

Left channel with 1/24 octave smoothing:
View attachment 403522

Right channel, 1/24 octave smoothing:
View attachment 403523

There are a few bass traps in the corners and two absorbers on each nearest side wall. No other treatment. Right speaker response is a bit rough here, but this is a challenging environment as well.

Looks good. General trend very flat. Any chance you could rescale the graphs for 50dB vertical. The 100dB is a bit too kind

 

[Duke]

It avoids the floor bounce and measures more even over a reflective floor.

Here's an average of both types of speakers at 5 different locations. Red is with woofer placed right underneath the top driver and green is with the woofer at the bottom.
View attachment 403491

Not only have we avoided the detrimental floor bounce between 200-300 Hz, but we also have achieved a more even response in the midrange.

Excellent job of taking early room interaction into account. Your design choice makes sense to me.

 

[Bjorn]

Here's higher resolution on the last two graphs at the narrow space. Still 1/24 octave smoothing.

It will measure flatter in a better/bigger space, which we will see later.

 

[Matt_Holland]

Here's higher resolution on the last two graphs at the narrow space. Still 1/24 octave smoothing.
View attachment 403529

View attachment 403530

It will measure flatter in a better/bigger space, which we will see later.

Thanks @Bjorn
Very nice room response.
They don’t lack bass do they!

 

[MarsianC#]

Bold take in Boxsim, PAW30ND and G50FFL WG (seemed kinda suitable), xover 600 Hz LR4, housing/baffle pi*thumb
Vertical directivity with hard floor, maybe a lot salt to add

Unoptimized! I guess this concept has real potenial.
Bjorn knowns his business for sure.

 

[Bjorn]

Bold take in Boxsim, PAW30ND and G50FFL WG (seemed kinda suitable), xover 600 Hz LR4, housing/baffle pi*thumb
Vertical directivity with hard floor, maybe a lot salt to add
View attachment 403670
Unoptimized! I guess this concept has real potenial.
Bjorn knowns his business for sure.

We'll see how close your simulation is
We use a lower cross over by the way. This pushes the vertical lobing lower in frequency, and at a point where it really isn't an issue anymore with the needed listening distance.

You can see some of the design goal in your simulation. Combination of controlled and narrow vertical directivity. Minimizing vertical reflections is very important in my opinion. We used a driver earlier that gave us wider vertical dispersion and this was only negative as it triggered more high gain early reflections.
Beaming/narrowing in the highest frequencies is unavoidable with this design, but IMO not really something that's negative as long as one is listening at the right height.

I know many of you want to see measurements, and they will eventually arrive. Patience please. Still waiting for the final model, which will arrive in February.

Some pictures placed in a different room than before.

 

[Bjorn]

The response in the new room looks good. Haven't worked much with placement yet though, and eventually I will treat the room acoustically. It's an L-shaped room.

The response below is with 1/12 Oct smoothing. As always, I never use any room EQ.

There are a few peaks here I don't like, but that's what you can get with some high reflective surfaces close to the mic and possibly around the speaker. Proximity to the front wall is not much here, but this is a speaker you can place close to the front wall with a good result.

The cancellation around 49 Hz is of course a standing wave issue in the room. Can either be minmized with subwoofer(s), maybe move out of it or treatment. I always start with treatment after placement since it solves the root problem which has several benefits. Moving out of it isn't always a practical poosible solution andr it can make the sound worse in other areas.

 

[Bjorn]

New version with wooden top plate. Will provide better and more pictures later.

 

[Bjorn]

A neafield measurement of the woofer indoor.

This is a raw measurement with absolutely no equalization of the woofer. 1/24 octave smoothing. The low frequency level needs to be taken with a grain of salt since this is indoor.

I dare to say it doesn't get much better than this in terms of an even response with no equalization. Bass reflex done correctly.

 

[holdingpants01]

so it plays up to 5kHz from basically the floor?

 

[Matt_Holland]

A neafield measurement of the woofer indoor.

View attachment 431075

This is a raw measurement with absolutely no equalization of the woofer. 1/24 octave smoothing. The low frequency level needs to be taken with a grain of salt since this is indoor.
View attachment 431076

I dare to say it doesn't get much better than this in terms of an even response with no equalization. Bass reflex done correctly.

No equalisation? How do you explain the ruler flat response from 70Hz-5KHz?

But very nice!