Kii Three have the purifi amp now
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Vera Audio midrange horn - polar measurements
- Thread starter Bjorn
- Start date
Kii Three have the purifi amp now
There was talk of an ‘all out’ design using Purifi drivers!
All the best for the New Year.
Keith
All the best for the New Year.
Keith
Imo the internal geometry of the TAD drivers is inferior to that of more modern drivers. The long, almost-straight-sided internal "snout" between phase plug and exit is a source of coloration. I have worked with the 4001 and 2002, and it's a time-domain aberration rather than a pure frequency-response aberration so it's not readily addressable via EQ.
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Duke you may well be right, I have no knowledge of driver design let alone compression drivers they were expensive though!
Keith
Keith
Da cynics
Member
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- Jun 21, 2020
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I remember this.
Could someone help me to think through my ABX result using Bayesian reasoning?
Priors: 1. For many years, I'd been certain that I could hear clear differences between bit-identical playback means (e.g., different USB cables, streaming vs. local playback, different software players and their bit-identical settings, etc.) - something that has bugged me no end over the years...
www.audiosciencereview.com
He, too, used powerful horns.
OP
- Thread Starter
- #46
I knew this would be controversial here. But in defence, this isn't something that's important to most. And clearly this isn't about selling expensive electronics considering the low cost of a miniDSP Flex.
The Hypex' DLCP has a SINAD of about 100 dB. That may very well be good enough, but it uses a bit of an odd sample rate which be the cause of both my experience and others who have tested I have only done the AB testing with digital in. According to someone else, the Hypex' was fine with analoge.
Either way, especially for those who listen in untreated rooms with high gain specular energy and resonances and long decay, it may not be an audible difference at all as these will have a masking effect. For someone who does mixing/mastering in a well treated room or an audiophile who equally listens in a critical environment, it's different IMO. Age/ears also come into play in these situations.
But disagreement is fine. Some people will never believe in something like this unless there's and ABX. Something I do understand.
The Hypex' DLCP has a SINAD of about 100 dB. That may very well be good enough, but it uses a bit of an odd sample rate which be the cause of both my experience and others who have tested I have only done the AB testing with digital in. According to someone else, the Hypex' was fine with analoge.
Either way, especially for those who listen in untreated rooms with high gain specular energy and resonances and long decay, it may not be an audible difference at all as these will have a masking effect. For someone who does mixing/mastering in a well treated room or an audiophile who equally listens in a critical environment, it's different IMO. Age/ears also come into play in these situations.
But disagreement is fine. Some people will never believe in something like this unless there's and ABX. Something I do understand.
Reasoning for the Hypex sample rate:
"The clock circuit is the same as that used in the CC1
except that the sampling rate is set to 93.75kHz instead
of one of the more traditional audio rates. This is specifically
done to improve the performance of the SRC chip.
An uncommon clock frequency reduces the odds that mix
products between the incoming clock and the internal
clock fall inside the PLL loop bandwidth of the SRC."
Personally I find Hypex to be transparent both with analog and digital inputs (but I am not objective in this matter).
"The clock circuit is the same as that used in the CC1
except that the sampling rate is set to 93.75kHz instead
of one of the more traditional audio rates. This is specifically
done to improve the performance of the SRC chip.
An uncommon clock frequency reduces the odds that mix
products between the incoming clock and the internal
clock fall inside the PLL loop bandwidth of the SRC."
Personally I find Hypex to be transparent both with analog and digital inputs (but I am not objective in this matter).
OP
- Thread Starter
- #48
This placement illustrates one of the clear benefits of this horn speaker.
It can be placed close to the side wall with basically no detrimental effect and even benefits from it.
How so? The combination of sufficiently narrow and broadband directivity means it avoids the nearest side wall reflection completely. Not only in the higher frequency like some horns may do, but all the way down to the Schroeder frequency. Meaning a true neutral result without the typical coloration from the nearest surface. And it picks up efficiency/gain with such a placement.
Whether a speaker should also avoid the opposite (from opposite wall) side wall reflection is a matter of discussion. With normal toe-in there will be a reflection here from the opposite wall. This means it's up to the customer if they want to have it reflective ala Toole, absorb it or diffuse it. I believe having this choice is the best. For example, one could use diffusion on the opposite side wall reflections to enhance spaciousness and envelopment. Something that's quite addictive and sounds great if the diffuser works to the highest frequencies. While removing it with absorption will give the highest insight to the recorded signal.
It can be placed close to the side wall with basically no detrimental effect and even benefits from it.
How so? The combination of sufficiently narrow and broadband directivity means it avoids the nearest side wall reflection completely. Not only in the higher frequency like some horns may do, but all the way down to the Schroeder frequency. Meaning a true neutral result without the typical coloration from the nearest surface. And it picks up efficiency/gain with such a placement.
Whether a speaker should also avoid the opposite (from opposite wall) side wall reflection is a matter of discussion. With normal toe-in there will be a reflection here from the opposite wall. This means it's up to the customer if they want to have it reflective ala Toole, absorb it or diffuse it. I believe having this choice is the best. For example, one could use diffusion on the opposite side wall reflections to enhance spaciousness and envelopment. Something that's quite addictive and sounds great if the diffuser works to the highest frequencies. While removing it with absorption will give the highest insight to the recorded signal.
OP
- Thread Starter
- #50
I can offer the speaker with a compression driver with aluminum diaphragm instead of beryllium as well. This brings down the cost substantially. The compression driver I'm using also sounds very open, clear and detailed with aluminum diaphragm.
It's been a while since I've made a good AB comparisons between aluminum and beryllium diaphragm. But my experience was that the difference in a direct comparison with shorting listening sessions was subtle. It's certainly not a day and night difference and you're paying a lot extra for beryllium. However, both my experience and others is that beryllium sounds easier on the ear over time. The lack of break up and less ringning makes it a tad smoother and this means IMO more with longer listening sessions. To quantify this with blind tests would likely be impossible, but it is the general experience by those who tried both.
But the horn is much more important than the compression driver as long as the latter holds good quality. If the horn is of poor quality, it's never going to sound great just because it's using a quality driver. Beryllium diaphragm is at best icing of the cake. I would much rather take a well designed horn with aluminum diaphragm vs a low quality horn with berylllium diaphragm. I have done the comparison.
As for TADs, the newer TAD 4003 is the better one. But it's not being produced anymore and had an insane price tag at the end.
OP
- Thread Starter
- #51
I'm going to to mention briefly a few other speakers we're also working on. When time is right, I'll present them in an own thread.
Obviously not many can fit such a large horn speaker like this and it may also be well above budget. But we'll have other options which are also speaker designs that I believe are different from the crowd out there and will also measure very even when placed in the room. As I've stated several times, a speaker with good spinorama data doesn't necesserarily mean it will meassure particular even when placed in an actual room. We design speakers where the chances for an even response above 120-150 Hz is much greater. Anyone is welcome to do an AB test vs other speakers with various placements, whether it's a cardioid speaker or another design.
1. Vera Audio Coherence 12 (I'll show some more pictures later which gives a different look on the proportions).
Approximate dimensions (may change slightly): 50 cm width x 23 cm depth x 128 cm height with feet (not shown on pictures). Platform is about 40 cm deep.
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, but not sure how many will consider an expensive DEQX for a speaker in this price range. A 4-channel amp is needed to buy separately with the external crossover and this can be chosen freely by the customer, though the gain should be equal.
Some key words:
- Coherent sound with one driver covering the treble and almost all of the midrange, thus the name Coherence
- Constant and wide horizontal direcitivty up to 5.5 kHz area and graduals narrows in the highs
- Minimizes vertical reflections with a narrow vertical directivity in part of the frequency range
- No floor bounce, meaning very even frequency response in the midbass area
- A super elliptical shape to minimize diffractions
- Very low intermodulation distortion with a planar driver and a 12" high quality midwoofer
- Very even frequency response on-axis
- Linear phase
- High sensitivity of around 95 dB
- Can play loud, especially at the important midbass area where one speaker can reach above 120 dB at 1 m at peaks
- Reaches high SPL in the subwoofer frequencies too, thus can work great without a subwoofer. 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!
- Feet that isolates the speaker from vibrations and not the typical spikes that most often simply enhances vibrations
- Thick cabinet material with a lot a bracing
Can obviously be tailored to the placement in the room (room gain and listening position) with the DSP. And it will be possible to hire assistance from us with this.
Finish: Glossy black. Considering also a second painting option and we're open to custom painting in RAL colors.
Prices are rough estimates and may change.
Estimated price with a balanced 4-channel miniDSP Flex: Below $5300 ex VAT and shipping
Estimated price with built in Hypex FA252 amp: Below $6200 ex VAT and shipping
Estimated release date: Hopefully before the summer of 2024
Following up with next speaker in the following post.
Obviously not many can fit such a large horn speaker like this and it may also be well above budget. But we'll have other options which are also speaker designs that I believe are different from the crowd out there and will also measure very even when placed in the room. As I've stated several times, a speaker with good spinorama data doesn't necesserarily mean it will meassure particular even when placed in an actual room. We design speakers where the chances for an even response above 120-150 Hz is much greater. Anyone is welcome to do an AB test vs other speakers with various placements, whether it's a cardioid speaker or another design.
1. Vera Audio Coherence 12 (I'll show some more pictures later which gives a different look on the proportions).
Approximate dimensions (may change slightly): 50 cm width x 23 cm depth x 128 cm height with feet (not shown on pictures). Platform is about 40 cm deep.
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, but not sure how many will consider an expensive DEQX for a speaker in this price range. A 4-channel amp is needed to buy separately with the external crossover and this can be chosen freely by the customer, though the gain should be equal.
Some key words:
- Coherent sound with one driver covering the treble and almost all of the midrange, thus the name Coherence
- Constant and wide horizontal direcitivty up to 5.5 kHz area and graduals narrows in the highs
- Minimizes vertical reflections with a narrow vertical directivity in part of the frequency range
- No floor bounce, meaning very even frequency response in the midbass area
- A super elliptical shape to minimize diffractions
- Very low intermodulation distortion with a planar driver and a 12" high quality midwoofer
- Very even frequency response on-axis
- Linear phase
- High sensitivity of around 95 dB
- Can play loud, especially at the important midbass area where one speaker can reach above 120 dB at 1 m at peaks
- Reaches high SPL in the subwoofer frequencies too, thus can work great without a subwoofer. 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!
- Feet that isolates the speaker from vibrations and not the typical spikes that most often simply enhances vibrations
- Thick cabinet material with a lot a bracing
Can obviously be tailored to the placement in the room (room gain and listening position) with the DSP. And it will be possible to hire assistance from us with this.
Finish: Glossy black. Considering also a second painting option and we're open to custom painting in RAL colors.
Prices are rough estimates and may change.
Estimated price with a balanced 4-channel miniDSP Flex: Below $5300 ex VAT and shipping
Estimated price with built in Hypex FA252 amp: Below $6200 ex VAT and shipping
Estimated release date: Hopefully before the summer of 2024
Following up with next speaker in the following post.
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OP
- Thread Starter
- #52
2. Keele & Omholt Technologies - CBT Atlantic
CBT is short for constant beamwidth transducer. A lot of papers on the CBT design here: https://www.keele-omholt-technologies.com/papers.php
I'm showing some pictures here of an early prototype cabinet without drivers. Finish may change from this.
This will also be an active speaker design, but probably only sold with an external crossover and 4-channel amp can be chosen freely by the customer. miniDSP, Danville dspNexus or DEQX are also options here.
Vertically this speaker is basically text book in constant vertical directivity and maintains this down to the Schroeder area. It's also very narrow vertically, where it avoids floor reflections (by using the floor as mirror) and greatly minimizes ceiling reflections.
While the Coherence 12 requires one to sit in order to get great treble, the CBT Atlantic sounds great both standing and laying down. I love the illustration below with Don Keele and with the older CBT36. It also work great in near field.
Horizontally this speaker will be wide and have a broadband uniform dispersion. However, it's important to understand that because of the narrow vertical dispersion it's only wide at certain height or at a small horizontal window. Compared to for instance a cardioid speaker, the early arriving reflections from this speaker will therefore be less in a typical living room.
The cabinet here is also a super elliptical shape to greatly minimize diffraction. This may the closest shape you get to a sphere acoustically.
Distortion is also very low here with the multiple drivers and sound is very coherent with one row of drivers covering the treble and most of the midrange. Unlike a traditional line array, with the CBT design the drivers sum as one up to a certain frequency (high in frequency and where lobing probably isn't audible anymore). There's no vertical lobing like tradtional speakers.
The CBT Atlantic can also play very loud and again; particular high in the important midbass area where we often the highest peaks in music. Below about 40 Hz it doesn't output as much SPL as the Coherence 12 because this is sealed design. But with room gain, it can get quite high here as well, and a subwoofer or more can of course be integrated with the DSP.
With a FIR crossover, we can also achieve linear phase with the speaker.
I don't have an estimated price here yet. This is much more costly speaker to manufacturer and assembly. But it's not going to have a typical high-end crazy price tag and will cost much less than the our large horn speaker. Direct sales keep prices down.
As for release time, that's also uncertain. Should know more in the next months. Could be that we only release a few pairs in the beginning to people who are willing to pre-order. That will help us get started and pre-orders could give a discount.
The widest part of the speaker is about 29 cm and obviously it's a tall speaker. Will get back with exact dimensions.
CBT is short for constant beamwidth transducer. A lot of papers on the CBT design here: https://www.keele-omholt-technologies.com/papers.php
I'm showing some pictures here of an early prototype cabinet without drivers. Finish may change from this.
This will also be an active speaker design, but probably only sold with an external crossover and 4-channel amp can be chosen freely by the customer. miniDSP, Danville dspNexus or DEQX are also options here.
Vertically this speaker is basically text book in constant vertical directivity and maintains this down to the Schroeder area. It's also very narrow vertically, where it avoids floor reflections (by using the floor as mirror) and greatly minimizes ceiling reflections.
While the Coherence 12 requires one to sit in order to get great treble, the CBT Atlantic sounds great both standing and laying down. I love the illustration below with Don Keele and with the older CBT36. It also work great in near field.
Horizontally this speaker will be wide and have a broadband uniform dispersion. However, it's important to understand that because of the narrow vertical dispersion it's only wide at certain height or at a small horizontal window. Compared to for instance a cardioid speaker, the early arriving reflections from this speaker will therefore be less in a typical living room.
The cabinet here is also a super elliptical shape to greatly minimize diffraction. This may the closest shape you get to a sphere acoustically.
Distortion is also very low here with the multiple drivers and sound is very coherent with one row of drivers covering the treble and most of the midrange. Unlike a traditional line array, with the CBT design the drivers sum as one up to a certain frequency (high in frequency and where lobing probably isn't audible anymore). There's no vertical lobing like tradtional speakers.
The CBT Atlantic can also play very loud and again; particular high in the important midbass area where we often the highest peaks in music. Below about 40 Hz it doesn't output as much SPL as the Coherence 12 because this is sealed design. But with room gain, it can get quite high here as well, and a subwoofer or more can of course be integrated with the DSP.
With a FIR crossover, we can also achieve linear phase with the speaker.
I don't have an estimated price here yet. This is much more costly speaker to manufacturer and assembly. But it's not going to have a typical high-end crazy price tag and will cost much less than the our large horn speaker. Direct sales keep prices down.
As for release time, that's also uncertain. Should know more in the next months. Could be that we only release a few pairs in the beginning to people who are willing to pre-order. That will help us get started and pre-orders could give a discount.
The widest part of the speaker is about 29 cm and obviously it's a tall speaker. Will get back with exact dimensions.
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OP
- Thread Starter
- #53
3. We're also considering some more horn speakers. I have love for horn speakers due to directivity control, low distortion with very "real life" quality, the engaging sound combined with high dynamics.
Unfortunately high quality horn speakers needs to be big. But it's certainly possible to make them smaller than the horn presented here and still achieve a great result. Considering two smaller versions and of course active designs with DSP. Have already worked some on the designs.
Unfortunately high quality horn speakers needs to be big. But it's certainly possible to make them smaller than the horn presented here and still achieve a great result. Considering two smaller versions and of course active designs with DSP. Have already worked some on the designs.
OP
- Thread Starter
- #54
Here a few more pictures of the Vera Audio Coherence 12 speaker. It's gloomy here today, so difficult to get enough light.
And here's the how rear looks on the prototype when external eletronics is used instead of the Hypex FA252 plate amplifier. It has a speakon connector (sorry for the present silver screws on the speakon).
Due to the narrow vertical disperson, and broad band uniform direcitivty the speaker can also work in a such narrow space with low ceiling height one on side as seen below.
Not many speakers sound good at this placement, but the Coherence 12 works great despite that there are only one absorption panel on each side wall. This speaker also sounds large, coherent with no break up in a sensitive area, and it also sounds more realistic than speakers with traditional drivers . The 12" woofer is very punchy and powerful. Absolutely no need for a subwoofer for music if one achieves an even response with the speakers.
Presently driven by our 4-channel prototype. Built like a tank and supert cooling to ensure long life span. Will be quite modest priced as well. Final model will look a little different.
And here's the how rear looks on the prototype when external eletronics is used instead of the Hypex FA252 plate amplifier. It has a speakon connector (sorry for the present silver screws on the speakon).
Due to the narrow vertical disperson, and broad band uniform direcitivty the speaker can also work in a such narrow space with low ceiling height one on side as seen below.
Not many speakers sound good at this placement, but the Coherence 12 works great despite that there are only one absorption panel on each side wall. This speaker also sounds large, coherent with no break up in a sensitive area, and it also sounds more realistic than speakers with traditional drivers . The 12" woofer is very punchy and powerful. Absolutely no need for a subwoofer for music if one achieves an even response with the speakers.
Presently driven by our 4-channel prototype. Built like a tank and supert cooling to ensure long life span. Will be quite modest priced as well. Final model will look a little different.
Bjorn you have some truly intriguing designs.
Keith
Keith
so this only the mid-range horn?Vera Audio is developing a horn speaker system. It consist of a midrange horn, a midbass horn and requires a bass/subwoofer solution. It will be active and offered with a separate high quality DSP.
The 2-horn system look like the following:
I'll show some measurements of the midrange/top horn. With the driver we're using, it's able to cover the range from approximately 500/600 Hz and all the up to the highest frequencies.
The measurements of a prototype horn were conducted in a small gym with the ground plane method.
Due to size of the facility, the measuremen isn't anoechoic and we couldn't measure far enough away in order to get the beamwidth 100% correct. The horn has a likely a narrower directivity then what's seen in these measurements. New measurements under better conditions will be made later.
The horizontal directivity without any gating looked like this:
A gating with 24ms isn't sufficient to rule out all reflections as there were reflections arriving as early at 15ms at certain angles, but is shown below:
The horn was also measured vertically.
Vertical directivity with no gating:
Vertical directivity with 24ms gating:
Conclusion
The midrange horn measured with an extremely uniform directivity. Horizontally the directivity is text book apart from a small widening at 800-900 Hz. Vertically the polar is also very constant with some minor abberations. The horn is able to maintain direcitivity both high in frequency and very low in frequency which is unusual for speakers. How low exactly will require measurements in a more anechoic environment.
https://www.vera-audio.com/
The speaker link gives an error for me
OP
- Thread Starter
- #58
It's a 2-way horn that requires a separate bass solution/subwoofer.
The 2-way horn looks like this:
Our subwoofer will get some aesthetic modifications, but prototype looked like this:
The subwoofer is a dual 18" design with horn loading in a small area.
Ok, I see, but the picture for the measurements who only one. So they were measure one by one and then combined? what is the xover freq?
OP
- Thread Starter
- #60
The polars are measured separately. However, there's a measurement of both indoor over a reflective floor at different heights here:
Vera Audio midrange horn - polar measurements
Vera Audio is developing a horn speaker system. It consist of a midrange horn, a midbass horn and requires a bass/subwoofer solution. It will be active and offered with a separate high quality DSP. The 2-horn system look like the following: I'll show some measurements of the midrange/top...
www.audiosciencereview.com
Crossover is in 500-600 Hz area. Not 100% decided yet, but it will not be higher than at 600 Hz or lower than 500 Hz.
Polars of both will be published later. Requires a very large space to measure it accurately.
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