Is there any EQ under 400 Hz applied to get a better room integration?
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Introduction of Vera Audio Coherence 12 - a high quality speaker many can afford
- Thread starter Bjorn
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OP
- Thread Starter
- #162
No EQ other than adjusting the gain of one standard low shelf. If the speaker was pulled out at lot from the front wall, the gain of that low shelf would had to be increased.
OP
- Thread Starter
- #163
It's probably a very valid point. Personally I have always disliked when only top recordings have been used at demoes. What I might do is to mention it before I put on a poor recording and play them generally less.
In both cases, room nodes seem to be very well controlled.
OP
- Thread Starter
- #165
Above approximately 110 Hz, the speaker generally measures very even in most rooms. That's a strength of the speaker design.
That's because the woofer is so closed to the ground that it's essentially coupled, or something like that? If you could explain it better I would be thankful.
OP
- Thread Starter
- #167
That's part of it and as much as I want to share. The result of the overall speaker design is a more even response measured in the actual room.
As I have measured before in this thread, a Spinorama wouldn't tell this and is why it is quite misleading. I'm sad to see this is becoming something many demand and also follow in their purchase. Not to mention that it even gives high scores to speakers with only directivity control in the treble and possibly also higher midrange (a classic collapsing polar), which is actually where the directivity control means a lot less! The understanding of the importance of a more broadband directivity control seemed to be much higher in the 70s and 80s, especially in the acoustic community.
Most of the high score Spinorama speakers will simply not measure that even when placed in the room. Plus many of them suffer from high specular energy in very sensitive area and crossover in a problematic area. Of course, many here don't believe some of things I'm sharing and demand a research. But in a AB test with level matching, which we have done of course, it's easy to hear the difference for trained listeners with various music material.
I have shared this measurement before where the drivers are identical and only placed differently in regards to the floor bounce. The speaker that avoids the floor bounce (green graph) was clearly better in listening session, despite that the polar is actually worse in some areas than the red one.
OP
- Thread Starter
- #168
Below are the ETC graphs at the Horten show in Norway. ETC shows the reflections from the room after the direct signal. One can see that early reflections are at a very low level, which is very important for clarity and details.
Left channel ETC:
Right channel ETC:
We used Broadsorbor Plus for the nearest side wall reflection and BAD Arc for the opposite side reflection. A double carpet on the floor but no ceiling treatment. However, the Coherence 12 avoids the ceiling reflections in the higher frequencies and also minimizes it some in midrange area.
Left channel ETC:
Right channel ETC:
We used Broadsorbor Plus for the nearest side wall reflection and BAD Arc for the opposite side reflection. A double carpet on the floor but no ceiling treatment. However, the Coherence 12 avoids the ceiling reflections in the higher frequencies and also minimizes it some in midrange area.
The main spinorama chart is useful for a lot of things, but I wouldn't rely on it for in-room behaviour below the transition frequency.
Anyway, it displays the on axis response of a speaker in an anechoic room. And the sound power and reflections DI integrate data over solid angles in a way that can obscure relevant details, so you have to know the limitations of what the spin chart can tell you and what it cannot.
OP
- Thread Starter
- #170
I set up a pair of Coherence 12 at a customers home recently.
This is how left and right measured with speakers 1 m out from the front wall, which is the position he used before. The room is untreated. No room correction was used.
He has less gain from the walls in the deep bass than what's typical, so we may raise that some. The cancellation between 60 Hz and 120 Hz is something I hope we can tame with better positioning and some treatment. The slightly high level around 150-200 Hz is also something we will try to remove mostly with some RPG Broadsorbor panels first and possibly additonal EQ later. Apart from that I'm happy with the response.
This is how left and right measured with speakers 1 m out from the front wall, which is the position he used before. The room is untreated. No room correction was used.
He has less gain from the walls in the deep bass than what's typical, so we may raise that some. The cancellation between 60 Hz and 120 Hz is something I hope we can tame with better positioning and some treatment. The slightly high level around 150-200 Hz is also something we will try to remove mostly with some RPG Broadsorbor panels first and possibly additonal EQ later. Apart from that I'm happy with the response.
OP
- Thread Starter
- #171
Tried placing Coherence 12 in the corners at a customer. Frequency response with 1/12 octave smoothing below with no EQ or acoustic treatment.
Added a few RPG Broadsorbor panels than evened out the response some and applied EQ to the 48 Hz peak. Adding more low frequency below 40 Hz is of course easy here with the miniDSP Flex in the chain.
Not many speakers work well placed in corners due to nearby surfaces end and early arriving reflections. But we can see, at least for the higher frequencies, that the ETC is quite free from early reflections despite of no treatment here.
Added a few RPG Broadsorbor panels than evened out the response some and applied EQ to the 48 Hz peak. Adding more low frequency below 40 Hz is of course easy here with the miniDSP Flex in the chain.
Not many speakers work well placed in corners due to nearby surfaces end and early arriving reflections. But we can see, at least for the higher frequencies, that the ETC is quite free from early reflections despite of no treatment here.
Attachments
Y-axis is customarily only 50dB.
Keith
Keith
Torin Krell
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Agreed - and a large woofer crossed to a tall narrow tweeter planar or ribbon driver will result in a significant dispersion disparity unless the crossover is very low. Unfortunately the narrow tweeter depicted does not seem to have enough surface area (not long enough) to go as low as is likely needed to cross over to the large woofer seamlessly. The baffle is also rather wide to house a tweeter centered within it. Off axis dispersion measurements will likely display some significant issues, despite on axis linearity.
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OP
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- #174
It's interesting to see how the speaker measures in different rooms. Below is an average of the VA Coherence 12 in four different rooms. Two of these rooms had little gain in parts of the deep bass which of course effects the average here. And nedless to say; this can of course be compensated by in the DSP that follows the speakers.
1/12 octave smoothing.
Notice especially the low level of comb filtering in the higher frequencies, and the lack of floor bounce with the result of a correct tonality that gradual falls towards the treble. There are not many speakers that measure as aaccurate at this above 120 Hz when placed in a room.
1/12 octave smoothing.
Notice especially the low level of comb filtering in the higher frequencies, and the lack of floor bounce with the result of a correct tonality that gradual falls towards the treble. There are not many speakers that measure as aaccurate at this above 120 Hz when placed in a room.
norman bates
Senior Member
crossover point ?
Slope ?
Slope ?
OP
- Thread Starter
- #176
Haven't shared it, but it's low.
Slope and crossover depends on the DSP being used. With external DSP (unamplified version) we're using a type of FIR. For the amplified version it's 4th order LR. The unamplified version with FIR is audible better.
norman bates
Senior Member
fair enough
Torin Krell
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Within a just released December SOS magazine review Phil Ward (speaker designer and studio gear reviewer) appears to be closely on the same page as I on this area of speaker design:
"Any conventional two‑way speaker, in which the full audio band is covered by a bass/mid driver and a tweeter, potentially incorporates a challenge: engineering a bass/mid driver that extends high enough in frequency to integrate with a tweeter that extends low enough is inherently difficult. If the bass/mid driver has a diaphragm large enough to reproduce low frequencies at a reasonable volume level, it will become significantly directional at the top end of its band; and at said top end of the band, a large diaphragm will have stopped moving as a whole and be working in a somewhat chaotic, resonant mode. The tweeter issue is that if the diaphragm is small and light enough to reach up to 20kHz with acceptably wide dispersion, it might struggle to reach low enough in frequency to integrate with the already bandwidth‑challenged bass/mid driver whilst retaining acceptable power handling and distortion levels. Furthermore, even when a bass/mid driver and tweeter are successfully integrated, there is likely to be a significant dispersion mismatch between them. The dispersion of the tweeter at the bottom of its band will be inherently wider than the dispersion of the bass/mid driver at the top of its band. The result of that will be potentially audible non‑linearity in the off‑axis response."
Phil Ward Dec 2025 Sound on Sound magazine, Amphion One 18X review: https://www.soundonsound.com/reviews/amphion-one18x
OP
- Thread Starter
- #179
The 12" in Coherence 12 isn't crossed over high as typical speakers, so it avoids the issue mentioned here. The top driver used can be crossed very low and it can be done with very low modulation distortion. Low crossover was a clear design goal here from the start.
Directional at higher frequencies is correct though but I don't see that as necessarily weakness.
Vertically, the Coherence is very narrow in both in the upper mids and the top frequencies. And it gradually narrows. Meaning we have less detrimental early reflections from floor and ceiling and which is IMO only a benefit. This was very clear when we compared it to drivers with a wider vertical directivity. The widest in the higher frequencies was coax drivers since these have a very small diaphragm (not shown in picture but many coax' were tested).
Horizontally we also have a narrowing towards higher frequencies, which starts around 4-5 KHz. Again, something I think is more of a benefit for most rooms than a drawback due to less reflections. After all, most place their speakers close to side walls.
But let's say you have a very wide room and place the speakers far from side walls. In that case, it's certainly possible that the horizontal narrowing above 4-5 KHz may be perceived as the speaker sounding a bit dark in the highest frequencies. In that case, EQ of the direct sound can easily be implemented with the DSP that follows. What we can't do something about, is widening the highest frequencies far to the sides. If that's important (for backround listening way outside the sweetspot), a speaker like the CBT seen below is a better speaker for sure.
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OP
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- #180
It's possible to order the Coherence 12 with a custom finish now as we're ordering more cabinets. Both different types of painting and veneer. Matte or glossy. With a custom finish, we need 50% pre-payment. Contact us very soon if you want this. Prices may vary some depending on finish.
We will also be offering the Coherence 12 with the option of the CoLinear Acoustics DSP-8C. The DSP-8C has 8 channels as oppose to only 4 channels with the miniDSP Flex. Meaning there's the possibility of running multiple subwoofers and/or using a Coherence 12 as a center speaker.
Will get back with price with the CoLinear Acoustics DSP-8C.
We will also be offering the Coherence 12 with the option of the CoLinear Acoustics DSP-8C. The DSP-8C has 8 channels as oppose to only 4 channels with the miniDSP Flex. Meaning there's the possibility of running multiple subwoofers and/or using a Coherence 12 as a center speaker.
Will get back with price with the CoLinear Acoustics DSP-8C.
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