The problem with the horizontal polar chart in post #13635 is the drastically narrowing off-axis response from 100 to 1kHz caused by the side by side 15" drivers won't match the off axis response of your high frequency horn at any frequency within that range.
A single driver won't have that problem.
One strategy to avoid that is to only use both woofers in the low end where needed. Have only one reach the midrange horn.
One product is the JBL Everest which has two woofers but allows only one to run up to match the midrange horn. https://www.jbl.com/floorstanding/DD67000RW-.html
My guess is they use fairly low Qts in a relative large sealed enclosure and want the low boost. They also provide a switch to control which woofer is full range.
“We” tend to focus on metrics. There is nothing wrong with this approach per se, but it is sometimes interesting to learn more about actual perceived differences between topologies. Yes, it's subjective and room dependent, but we already knew that.
Earlier I referred to different preferences between Westerners and Asian people.
The latter group prefers a 'lighter tonal balance' > less prominent low-end and more mid/high output + extension.
Despite these differences, I believe there is much to learn from the Asians, especially the Japanese, considering their impressive heritage in audio engineering.
An excerpt from one of the more prominent Japanese audio blogs on dual woofer systems:
Horizontally mounted twin woofer system (JBL Everest DD66000/67000)
This speaker is extremely luxuriously constructed, using a large horn for the mid-high range and two large woofers at the bottom for the low range.
With speakers this large, the sound reproduced is powerful and amazing, something that is hard to get at home.
The sound quality is also excellent, with the clear, fresh mid- and high-range tones that are unique to a large horn and powerful bass that resonates through your body. Because it is driven by two large woofers (double woofers), the balance ends up with more bass.
This speaker's large horn provides good/powerful coverage of the mid- and high-range frequencies, so even if there is excessive bass, the sound does not become muddy due to being overwhelmed by the mid- and high-range frequencies.
Exceptional double woofer system
A vertical twin type large horn speaker is a speaker that has one large woofer above and one large woofer below the mid-to-high range (horn).
Even with a vertical twin woofer system, the sounds reproduced from the two woofers can be bassy, but because the sound axes are aligned, the bass is not diffused excessively to the side and the large rectangular horn for mid- and high-range frequencies effectively suppresses this excessive bass.
To be precise, the mid-to-high range reproduced by a large horn has a higher density of sound due to the directionality of the horn, and this density of the mid-to-high range can effectively cover up the overlapping bass sounds.
If the double woofers were placed under the horn, the bass would spread too far to the sides and would not be able to be covered by the high density of the mid-to-high range reproduced from the horn, resulting in even more excessive bass.
Although this large vertical double woofer horn speaker is the best method among double woofer types, it has the disadvantage that it requires a lot of material and is therefore a very expensive speaker.
It could be said to be the ultimate form of a horn speaker, or even the ultimate form of a speaker.
A possible objection is that the most ideal speaker for audio reproduction has a flat response from ultra-low to ultra-high frequencies.
However, even a well-made horn speaker will have distorted frequency characteristics because sound will be reflected at the opening of the horn.
Because of this disturbance, it is not possible to create a flat response horn speaker.
In other words, no matter how well designed a horn speaker is, it is impossible to achieve the ideal flat response with high fidelity reproduction, and compromises must be made with some degree of distortion in the frequency response.
However, even though horn speakers cannot reproduce flat frequency characteristics, there are many attractive aspects of the sound they produce.
The appeal of horn speakers is the freshness of their mid-range sound. The fresh, clear sound of the mid-range of horn speakers is hard to obtain with other speakers.
Vertical twin woofer type horn speakers are the most well-balanced of all horn speakers, and if built well, you can expect the best sound quality.
Earlier I referred to different preferences between Westerners and Asian people.
The latter group prefers a 'lighter tonal balance' > less prominent low-end and more mid/high output + extension.
Despite these differences, I believe there is much to learn from the Asians, especially the Japanese, considering their impressive heritage in audio engineering.
An excerpt from one of the more prominent Japanese audio blogs on dual woofer systems:
Horizontally mounted twin woofer system (JBL Everest DD66000/67000)
This speaker is extremely luxuriously constructed, using a large horn for the mid-high range and two large woofers at the bottom for the low range.
With speakers this large, the sound reproduced is powerful and amazing, something that is hard to get at home.
The sound quality is also excellent, with the clear, fresh mid- and high-range tones that are unique to a large horn and powerful bass that resonates through your body. Because it is driven by two large woofers (double woofers), the balance ends up with more bass.
This speaker's large horn provides good/powerful coverage of the mid- and high-range frequencies, so even if there is excessive bass, the sound does not become muddy due to being overwhelmed by the mid- and high-range frequencies.
Exceptional double woofer system
A vertical twin type large horn speaker is a speaker that has one large woofer above and one large woofer below the mid-to-high range (horn).
Even with a vertical twin woofer system, the sounds reproduced from the two woofers can be bassy, but because the sound axes are aligned, the bass is not diffused excessively to the side and the large rectangular horn for mid- and high-range frequencies effectively suppresses this excessive bass.
To be precise, the mid-to-high range reproduced by a large horn has a higher density of sound due to the directionality of the horn, and this density of the mid-to-high range can effectively cover up the overlapping bass sounds.
If the double woofers were placed under the horn, the bass would spread too far to the sides and would not be able to be covered by the high density of the mid-to-high range reproduced from the horn, resulting in even more excessive bass.
Although this large vertical double woofer horn speaker is the best method among double woofer types, it has the disadvantage that it requires a lot of material and is therefore a very expensive speaker.
It could be said to be the ultimate form of a horn speaker, or even the ultimate form of a speaker.
A possible objection is that the most ideal speaker for audio reproduction has a flat response from ultra-low to ultra-high frequencies.
However, even a well-made horn speaker will have distorted frequency characteristics because sound will be reflected at the opening of the horn.
Because of this disturbance, it is not possible to create a flat response horn speaker.
In other words, no matter how well designed a horn speaker is, it is impossible to achieve the ideal flat response with high fidelity reproduction, and compromises must be made with some degree of distortion in the frequency response.
However, even though horn speakers cannot reproduce flat frequency characteristics, there are many attractive aspects of the sound they produce.
The appeal of horn speakers is the freshness of their mid-range sound. The fresh, clear sound of the mid-range of horn speakers is hard to obtain with other speakers.
Vertical twin woofer type horn speakers are the most well-balanced of all horn speakers, and if built well, you can expect the best sound quality.
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My brother listened extensively to the DD67000 in combination with various amplifiers.
In full range mode, the system is not suitable for SET amps (Audio Note Ongaku), but this can be overcome with solid state on the woofers.
An Ayre gave a more satisfactory result than the obvious Levinsons.
These speakers require some space to breathe.
In full range mode, the system is not suitable for SET amps (Audio Note Ongaku), but this can be overcome with solid state on the woofers.
An Ayre gave a more satisfactory result than the obvious Levinsons.
These speakers require some space to breathe.
Hi,
only if horn profile curvature is not gradually changing, iow is not a good design. You can make a horn with pretty much ideal output, without any hints of secondary sounds, iow no reflection at mouth or any other issues. This can be a freestanding horn, or one that terminates to a baffle, but then the baffle would likely diffract and show the issues.
Probably the most interesting character I see from pretty much every model of large monitor that I've seen, is that no one is using a sealed cabinet.
In my mind I know why people have favor for these 15" side by side woofer multi ways. If those people think they like that, try two 18's paired together.
So I am entertaining two 15's side by side with a 15" slot down the middle, to widen the horizontal pattern. Problem is, I have no way to simulate this to see how comb filtering plays out.
In my mind I know why people have favor for these 15" side by side woofer multi ways. If those people think they like that, try two 18's paired together.
So I am entertaining two 15's side by side with a 15" slot down the middle, to widen the horizontal pattern. Problem is, I have no way to simulate this to see how comb filtering plays out.
It's very simple: sealed does not provide the required efficiency and extension at the low end.
Tbh, I've slowly started to ignore the discussions about ported vs sealed.
As usual, it all depends...
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pretty sure they do this in some pa line arrays but I can't remember why I think it's to reduce the center to center distance between cabs .
These high sensitivity LF drivers don't get low in a sealed cabinet.
But when aiming for the highest possible audio reproduction a (double) bass array is the way to go. So you solve the 20-100Hz area as good as possible and then you are free to use some smaller drivers for the rest of the lower midrange.
But with 2way ... there are compromises.
But when aiming for the highest possible audio reproduction a (double) bass array is the way to go. So you solve the 20-100Hz area as good as possible and then you are free to use some smaller drivers for the rest of the lower midrange.
But with 2way ... there are compromises.
Along similar lines, ime big woofers which have nice enough midrange for use in a high-end large-format two-way have parameters which do not work well in a sealed box, at least not without subwoofage for the bottom couple of octaves.
Yes, a 2.5 way works well, but requires another crossover point, which Camplo wants to avoid.
Good feature, allows to pick which compromise is better ;^).
Imo there is a conceptual difference between "two-way speakers with subwoofers optional" and "two-way speakers with subwoofers mandatory". The former would arguably be a two-way concept which may be augmented with subs; and imo the latter would clearly be a three-way concept.
In my opinion, the Faital 15PR400 paired with a good big horn in a big vented box would be a "two-way speaker with subwoofers optional", whereas the same components in a sealed box would be a "two-way speaker with subwoofers mandatory".
Below is an example of a vented-box "two-way speaker with subwoofers mandatory" before shipping to a client for installation in a recording studio. Protective highpass filter also mandatory.
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I'm at 3 channels right now, not cause I want to but out of necessity
What I am envisioning is the above with the PPSL taking up part of the cabinet and exit below the dual 15's in a 9"X5.5" terminus. I have come to the conclusion that my goal seems to be really, reducing baffle size. Particle velocity reaches 16(m/sec) near max spl