Cheers. I meant to ask for a close measurement. Good call.
Your GD is a little higher than the headphones in the linked paper. (9vs4ms) The min. group delay in REW is prob the thing to compare to.
Check that the GD at 50hz is less than 5ms and the decay is less than 500ms. That seems to be the bar from the published tests. Decay and GD are separate issues.
The perception of decay issues changes with the volume level. The graph on the left is showing the threshold on headphones where the GD issues were removed with FIR.
from " A LISTENING TEST SYSTEM FOR MEASURING THE THRESHOLD OF AUDIBILITY OF TEMPORAL DECAYS " https://www.genelec.com/publications
So try cranking it up too!
I've only made 2 subs so there is that. Maybe I am reading too much into the audibility you describe.
Hi.
There are papers that show they are comparable (can't find with a quick search ATM- think they are on AES). That is why people do headphone studies.
I thought the same as you too based on my gut. But at some point, thresholds will show in all forms. The ear bone is part of bass sounds the louder you listen- this does not change if there are headphones or a speaker 30ft away.
For sure a room adds more confusion to listening.
I am just trying to draw a line through some diff. papers. The papers that isolate issues are the ones I like the most.
They are adding decay in that paper. I think it is more about nothing beaming or standing out in a small range.
Looks like more than -30db.
Actually that is not the case.
Having used headphones for noise control projects for decades we knew that the physical sensation of LFs was required for a valid psychoacoustic perception. Headphones did not provide this so addition LF augmentation was required.
But, for the most part headphones for psychoacoustic studies are so convenient that they are used regularly. Almost all of our studies used them.
at 500ms the graphon the right is down about -20db
A very even decay character. Just like the we want from the FR, no large peaks or valleys, but in regards to burst decay
Anyone familiar with this DIY loudspeaker? Claiming "One of my DIY designs in 2010. 2x18" BMS woofers, 2" BMS coaxial in a horn, 1" BMS in rear horn. Cardioid 20-20 kHz."
"Woofer box is resistance enclosure."
https://web.archive.org/web/20170429170853/http://kimmosaunisto.net/KS-1804/KS-1804mk2.html
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cardiod vs 23" tractrix horn, Comparing the lower end of the horns directivity to the 18" cardiod design. Unfortunately the Large horns measurements are cutoff....It should start to really directivity just below 600hz, and the graph obliges. The Cardiod speaker is crossed at 400hz, yet has as much directivity as the large horn at 400hz....On second look, the horn is likely about the same size as a 200hz tractrix lol
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The transition from the mid to the HF driver is so obvious. One reason why I dislike this approach. That problem will always be there.
Compared to the FR of the 200hz tractrix
That theres a good amount of directivity around 400hz that I can't say comes from the horn looking at the the FR in my previous post
That theres a good amount of directivity around 400hz that I can't say comes from the horn looking at the the FR in my previous post
Are you akin to hearing this error? I mean do you look at the chart and can easily imagine how this polar would sound, in effect. I can see something happening in the off axis around the XO. I would think there is a peaking frequency 400-700hz but its also -15db....
A cardioid has rather wide directivity frontally, and a deep horn is narrow, and has minimal spl outside it's beam. I remember kimmosto saying that he made this to overcome room reflections, but he didn't like the sound after all. He added a rearside small horn to get some more ambient sound above 1kHz later on.
Down till it looses directivity, the horn that is...I did not know that the cardioid effect could be achieved so easily. I have pictures of this system on my computer somewhere, showing for the resistive enclosure design a little more.
Outside of Cardioid polar, it would seem that such a box would be desirable for tonality? It seems a little open baffle like, maybe in between. I would be nice if you could fill the cavity with damping material.
I can't picture what the dynamics would be like.....Less box resonance, but non the less, some, and then the cardioid action improving phase, helps improve dynamics as well doesn't it? Less reflections, less, decay.
Most importantly, no cancellation of bass like a open baffle dipole, so, dual 18's would have similar dynamics to a Sealed box, wouldn't it?
I have all the materials to copy this style of "cardioid" but I am wondering why no one talks much about it, or recommends it, speaking towards this style of cardioid enclosures specifically. I see @mabat is making progress using ATH to design passive cardioid. Maybe now we will see more people implement pass cardioid in unique ways.
I wish I knew the theory behind this approach? The selection of rib size and spacing, etc. Pros n Cons, of this vs something like The Dutch or some of the other designs using a single port on each side. I just seen one design by Mabat where the cardioid resistive vent wrapped around the top of the enclosure. If I were to oversimplify what I see in these pictures....just put slots everywhere but the rear, put a sheet of porous craft material over the slots and call it a day. Obviously not that easy but does anyone have reading to better understand how this works? or an explanation and break down of the resulting performance in contrast to other popular solutions.
Active Cardioid is something I have not seen a lot of..... at least above 200hz or so, where excursion is small for most large drivers, even in a small sealed cab if not sealed back woofer, it would seem that this would be an ideal solution. If trying to reach sub range, efficiency would be an issue....I am imagining a large box with stacked 18's on the front and sides...and rear? Does cardioid ruin room gain? Is the corner an issue? No more corner loading?
Dutch
Also Dutch
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Hi,
such passive cardioid cancels bass like dipole give or take, hence two 18". One could make it 3-way system with omni bass as well. Cardioid action can be roughly 2 octaves before penalty on bass requires huge drivers so its not particularly suitable for a two way system.
Cardioid action in principle is easy to achieve but in reality will require some prototyping to get what you want. My perspective to such box is more about the box than the pattern, it can be really small, easy and cheap built as mid for a 3-way system. Sound inside box is harnessed to do work (cancel out sound to back towards front wall) and sound outside is harnessed to do work canceling the sound that would normally bounce around inside 😀 Baffle dimensions stay small (no baffle) so diffracting bandwidth is minimized. In a way, this removes box from the sound without hard to manufacture huge box with huge roundovers and all. Any panel on the box are very small so not much resonance, no bracing, no internal modes on pass band and the leaks ensure there really isn't any. Its relatively problem free solution for mid, small, easy and cheap to manufacture if prototyping doesn't count. Bass is traded-off.
Open baffle would be even easier to build and tune as there is no tuning involved, so if the speaker can be placed further into room and toed in to take advantage of dipole pattern then dipole would be wiser in my opinion. If the speaker needs to be close to a wall so that dipole doesn't work then perhaps cardioid pattern is better option of the two. If speaker can be very close to wall then omni might be even better as the pattern would be there due to the wall and on loss in bass. Dipole and cardioidish are alike, main difference is that the side nulls of dipole are at different angle, cardioidish variety have them anywhere from 90-180deg. Ideally the nulls reduce influence of early reflections, tailor fit to your speaker positioning. I need to have speakers on front wall so some cardioidish pattern is logical. Positioning is not ideal since even the nulls need some space to form towards the wall.
such passive cardioid cancels bass like dipole give or take, hence two 18". One could make it 3-way system with omni bass as well. Cardioid action can be roughly 2 octaves before penalty on bass requires huge drivers so its not particularly suitable for a two way system.
Cardioid action in principle is easy to achieve but in reality will require some prototyping to get what you want. My perspective to such box is more about the box than the pattern, it can be really small, easy and cheap built as mid for a 3-way system. Sound inside box is harnessed to do work (cancel out sound to back towards front wall) and sound outside is harnessed to do work canceling the sound that would normally bounce around inside 😀 Baffle dimensions stay small (no baffle) so diffracting bandwidth is minimized. In a way, this removes box from the sound without hard to manufacture huge box with huge roundovers and all. Any panel on the box are very small so not much resonance, no bracing, no internal modes on pass band and the leaks ensure there really isn't any. Its relatively problem free solution for mid, small, easy and cheap to manufacture if prototyping doesn't count. Bass is traded-off.
Open baffle would be even easier to build and tune as there is no tuning involved, so if the speaker can be placed further into room and toed in to take advantage of dipole pattern then dipole would be wiser in my opinion. If the speaker needs to be close to a wall so that dipole doesn't work then perhaps cardioid pattern is better option of the two. If speaker can be very close to wall then omni might be even better as the pattern would be there due to the wall and on loss in bass. Dipole and cardioidish are alike, main difference is that the side nulls of dipole are at different angle, cardioidish variety have them anywhere from 90-180deg. Ideally the nulls reduce influence of early reflections, tailor fit to your speaker positioning. I need to have speakers on front wall so some cardioidish pattern is logical. Positioning is not ideal since even the nulls need some space to form towards the wall.
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Thanks for your comment. I was thinking along the same lines as what you said here. My thought was that I want to be able to corner load the speaker but also have cardioid polar for the better FR if Corner loading was not the choice.
Hmmm.... in that case, I think that as hard as it was to reach the dynamic goals I've reached so far, using sealed. Then Passive Cardioid like the above system would leave me wanting. I've grown use to the SQ that Headroom gives lol. @tmuikku I think it is you who is fluent in VituixCad? In your experimentation, how does act ive cardioid fit into the puzzle? What do you say? A woofer cab with 8 - 18"s on it, with separate cabinet space for pairs of stacked woofers for each side.....Every side but the front side, used for cancellation?
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Yeah I'm quite fluent with VCAD but haven't really done active cardioid sims because passive cardioid is more appealing to me for my home system application. Well, also my passive cardioid sims are just emulations done with active parts, but I haven't really explored possibilities of active cardioid system. Member nc535 has posted several active cardioid system sims though, look them up.
Active cardioid has great control over pattern but "box problems" remain. I'm interested in very small construct (box), not going to happen with active cardioid. Active cardioid is easier to simulate and very little prototyping needed, safe bet if pattern control is what you are seeking. As pattern is made with destructive interference the bass power is lost also in active cardioid. I'm using passive cardioid mid down to frequency where monopole bass fits within 1/8wl from front wall, so effectively cardioid as well, no front wall reflection problems (in theory).
If you have requirement for very high SPL capability then perhaps neither is good solution. If space and positioning is not a problem in your system you could make bass horn, pattern control down to 100Hz is not that big of a horn. Great dynamics. Although, I'm not sure if excessive dynamics is proper requirement, anything excessive means trade-off somewhere else 🙂
Active cardioid has great control over pattern but "box problems" remain. I'm interested in very small construct (box), not going to happen with active cardioid. Active cardioid is easier to simulate and very little prototyping needed, safe bet if pattern control is what you are seeking. As pattern is made with destructive interference the bass power is lost also in active cardioid. I'm using passive cardioid mid down to frequency where monopole bass fits within 1/8wl from front wall, so effectively cardioid as well, no front wall reflection problems (in theory).
If you have requirement for very high SPL capability then perhaps neither is good solution. If space and positioning is not a problem in your system you could make bass horn, pattern control down to 100Hz is not that big of a horn. Great dynamics. Although, I'm not sure if excessive dynamics is proper requirement, anything excessive means trade-off somewhere else 🙂
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I would say that a bass horn that had directivity at 100hz would need to be at least 135" wide. Maybe some say 45" I don't know.