Dipoles are good at constant directivity but as @sarumbear said they are not suited to small UK sitting rooms.
we can limit the dipole range to from 2KHz to 20KHz like the LXmini, removes the placement restrictions.
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Dipoles are good at constant directivity but as @sarumbear said they are not suited to small UK sitting rooms.
To quote yourself:Is there consensus on whether it's better to have the sharp (off-axis) transition between omni and narrow-constant directivity of the 8c:
I don't know, are you asking for me personally or generally?
Really want to avoid a waveguide unless it is part of the tweeter design. Amir has reviewed a number of speakers with good directivity without needing waveguides. This was already discussed in r1.
Linkwitz's design is a dipole and my question was around the OB bass module. Ofc, the upper part is going to need space as the those drivers are open baffle and have significant energy output from the back.
I had already planned a separate the bass module and upper monitor, so not sure where the confusion may be. The high level goal is to improve directivity over r1. So r1 is the reference. Am still not clear on where the most audible improvement in directivity may come from. At the risk of repeating myself, am interested in the audible benefit. Lacking this, not interested at all in something superficial like making a prettier polar map or chasing other cool designs without knowing the problem they are trying to solve...
For example, if controlling bass directivity has the benefit of clearer bass and better room integration, then this seems like a good goal. However, if improving the directivity above 5 kHz will be more audible, then would not spend time or money for better bass directivity. As I have not heard a kii 3 or the d&d 8c, am relying on others to articulate the benefits.
Hoping the discussion turns towards what benefits a given feature has and less of how a feature may have been accomplished.
To quote yourself:
But seriously: obviously, in most systems, the bass is omni. However the gradient system has specific directivity for mid and high, and I'm not sure that is the best idea. You'd either want a smooth transition or quite uniform throughout, exactly like the two examples you posted already.
I'm inclined to think the D&D version is the better deal overall.
Well, it's probably the best one can do given the size restrictions. All in all, it's pretty amazing for such a small speaker.It doesn't look to me like the D&D produces a smooth transition between constant and omni...
Theoretically, kind of. I haven't tried it, so I can't say how realistic the result is.Can this be modeled in vituixcad directly I wonder?
With the available 4 or 8 ohm drivers, the combination of three drivers is rather unusual. Therefore, two front woofers were chosen for the comparison.For a good comparison you need the three front plus rear enabled/disabled. Having 2 or three woofer on the front already changes directivity. I think things might improve when you filter the rear for < 500 Hz.
Yep, that's on my list too. I actually wanted to wait with further simulations until it is clear whether such a concept is being considered, since the effort for the simulations is not insignificant.Also try mounting the rear driver all the way down like Genelec goes. That will make the path length different to the listener longer.
This gets complicated quite quickly due to the wiring of the drivers and that you also have to keep an eye on the overall impedance of the bass module.You could also experiment with an all-pass passive filter to make the delay longer. That won’t be cheap though…
Yes, you are right and for a single project this would be a very good option, but the bass module is now intended to serve as a platform for many other speaker tops. A single channel for the MT unit is quite limiting, makes the top speaker more expensive (passive crossover parts) and less flexible.If three processing channels per audio channel is the limit, one could do a hybrid crossover - passive MT unit (passive parts to roll off the drivers and correct for individual driver breakup, use the processing channel to set the response, a la JBL 7-series i-line) + bass. That gives you 2 channels for bass.
There is an example here which is about as accurate as a Vituix sim can be of side slots, plenty of real prototype measurements later to compare withTheoretically, kind of. I haven't tried it, so I can't say how realistic the result is.
If you carry on in the thread linked above DonVK has made some ABEC simulations and there is some information on the simulation of side ports through lumped elements. If Don manages to make good plane wave tube measurements of different acoustic materials then a better model could be made. Given that most of the things necessary to make a good passive cardioid are known, measuring them is harder than making them.But there the simulation effort is again significantly higher. Therefore, do not expect to see this in the near future - unless someone makes me an "Indecent Proposal"
If you don't agree how about showing the math behind your argument? Or a reference where someone did?I don't agree in this case. What instead is you have a leaky box--the "vent" is not storing energy, and instead is modeled as a resistor, Rx, whose value is independent of frequency, and introduces another order to the system with the loss the RC product of Rx and Cab (cabinet compliance). In any e-vent, the system is now 3'rd order and rolls off at -18dB/octave. Been kicking around for 50 years now, but is seldom employed except unintentionally by crappy cabinet construction . http://diyaudioprojects.com/Technical/Aperiodic/Aperiodic-Closed-Box-Loudspeakers.htm
Since you brought up the point about audible benefits, I wonder how much the subject of high sensitivity is worthy of exploration, as per the topic below:
Do high-efficiency speakers really have better 'dynamics'?
A very experienced audiophile on another forum recently asserted that high-efficiency speakers were inherently more dynamic than other types. By high-efficiency I believe he meant >92 dB sensitivity; by "dynamic" I believe he meant more brilliant response to transient signals. Do hi-eff...www.audiosciencereview.com
I don't agree in this case. What instead is you have a leaky box--the "vent" is not storing energy, and instead is modeled as a resistor, Rx, whose value is independent of frequency, and introduces another order to the system with the loss the RC product of Rx and Cab (cabinet compliance)
We had this discussion back in March when Erin's D&D 8c review came out.If you don't agree how about showing the math behind your argument? Or a reference where someone did?
The question is what is that math behind the suggested behaviour, which is different to the standard resonator? Why would reducing the efficiency of the port will do anything other than reduce the Q at the resonance frequency?The question now is whether the damping material changes the behavior of the slot so much that the characteristic of the Helmholtz resonator is completely lost.
my expertise on this topic is abysmal in comparision to the two of you, but the simulations he produced should be 'mathematically representative' of what is going on. Isn't that true?We can discuss as much as you want but without mathematical representation of the suggested behaviour there’s no possible way to agree on anything.
I apologise if I missed but what I remember was a discussion about the possible cause of distortion on the 8C. Those simulations were about standard port designs that acted like ports. May I ask you to please point me to calculations where port stuffing causes the port to stop acting like a resonator and shifts the frequency as you suggested.my expertise on this topic is abysmal in comparision to the two of you, but the simulations he produced should be 'mathematically representative' of what is going on. Isn't that true?
The entire history of loudspeaker design is people imagining things that are audible and important and then spending enormous amounts of time implementing their ideas only to find that their design priorities are not supported by psychoacoustic research. Most of the 'errors' that designers seek to correct are things they see in measurements first, not from reported listener experiences. The history of technical 'issues' which designers seek to correct is exactly the same as the history of acoustical measurements. First they were obsessed with flat axial FR and bass Q, because that's all they could measure or model. Then in the 80s, you have software acoustic measurement and designers become obsessed with 'transient perfection' because it's one of the new things their tools showed them. More measuring tools create more imaginary issues and invented solutions.
Harmonic distortion and IMD is an example of this. Harmonic distortion is a crude metric that mathematically characterizes one simple type of deviation from an ideal signal. There is absolutely no reason to assume that it is audible except in extreme cases, and if it is audible, it is almost certainly the wrong metric to use to characterize the audibility. People have this intuition that orchestral music is 'complex' presumably because it has a lot of instruments, and this is more susceptable to IMD distortion, but let's be real. What is 'complexity'? A square wave has an infinite series of odd harmonics, is it 'complex'? The sound of a single familiar voice almost never sounds correct played back - is it 'complex'? Is IMD the correct metric to describe why your orchestral recordings sound like a cloudy soup? Unlikely.
A lot of audio designers clown audiophiles like Romy the Cat who has this very famous multiway horn system, all DIY, with a mishmash of exotic and unusual drivers such as a compression driver from the 50s, an english PA speaker for the bass, and a huge RAAL tweeter for the treble, all connected to passive line level crossovers and tube amps. And I would agree that it is not a cost effective way to create good sound - but consider the methodology. Romy the Cat doesn't 'suppose' something sounds bad due to measurements - he tries to make determinations about what he wants his system to sound like. He identifies the problem with the reproduction first, in his own experience and in his own terms. Then, he makes a change and listens to it.
There are obvious problems with this approach from an engineering perspective, but making assumptions about the importance of technical issues is not a shorter path to audio quality. Rick seems to want to bring the focus to audibility, but what do we really know about what performance metrics matter?
Lots of bass, user adjustable for quantity and to correct room issues. Smooth off axis without major resonances down to Schroeder. Narrow mid/treble dispersion less room-dependent than wide, but not necessarily better. What else does psychoacoustic research say about speakers?
I apologise if I missed but what I remember was a discussion about the possible cause of distortion on the 8C. Those simulations were about standard port designs that acted like ports. May I ask you to please point me to calculations where port stuffing causes the port to stop acting like a resonator and shifts the frequency as you suggested.
I’m buying a pair of single driver speakers...The entire history of loudspeaker design is people imagining things that are audible and important and then spending enormous amounts of time implementing their ideas only to find that their design priorities are not supported by psychoacoustic research. Most of the 'errors' that designers seek to correct are things they see in measurements first, not from reported listener experiences. The history of technical 'issues' which designers seek to correct is exactly the same as the history of acoustical measurements. First they were obsessed with flat axial FR and bass Q, because that's all they could measure or model. Then in the 80s, you have software acoustic measurement and designers become obsessed with 'transient perfection' because it's one of the new things their tools showed them. More measuring tools create more imaginary issues and invented solutions.
Harmonic distortion and IMD is an example of this. Harmonic distortion is a crude metric that mathematically characterizes one simple type of deviation from an ideal signal. There is absolutely no reason to assume that it is audible except in extreme cases, and if it is audible, it is almost certainly the wrong metric to use to characterize the audibility. People have this intuition that orchestral music is 'complex' presumably because it has a lot of instruments, and this is more susceptable to IMD distortion, but let's be real. What is 'complexity'? A square wave has an infinite series of odd harmonics, is it 'complex'? The sound of a single familiar voice almost never sounds correct played back - is it 'complex'? Is IMD the correct metric to describe why your orchestral recordings sound like a cloudy soup? Unlikely.
A lot of audio designers clown audiophiles like Romy the Cat who has this very famous multiway horn system, all DIY, with a mishmash of exotic and unusual drivers such as a compression driver from the 50s, an english PA speaker for the bass, and a huge RAAL tweeter for the treble, all connected to passive line level crossovers and tube amps. And I would agree that it is not a cost effective way to create good sound - but consider the methodology. Romy the Cat doesn't 'suppose' something sounds bad due to measurements - he tries to make determinations about what he wants his system to sound like. He identifies the problem with the reproduction first, in his own experience and in his own terms. Then, he makes a change and listens to it.
There are obvious problems with this approach from an engineering perspective, but making assumptions about the importance of technical issues is not a shorter path to audio quality. Rick seems to want to bring the focus to audibility, but what do we really know about what performance metrics matter?
Lots of bass, user adjustable for quantity and to correct room issues. Smooth off axis without major resonances down to Schroeder. Narrow mid/treble dispersion less room-dependent than wide, but not necessarily better. What else does psychoacoustic research say about speakers?
When doing these kind of experiments, I tend to not concern with those kind of things at first. It only leads too many variables that change at ones. Better to first prove or compare single concept, and if it has merit, one can see how things like impedance can work out.With the available 4 or 8 ohm drivers, the combination of three drivers is rather unusual. Therefore, two front woofers were chosen for the comparison.
Looks like it indeed makes quite a difference. But I suspect removing the driver in favor of a lot will save one woofer, and a bigger effect due to the larger delay.Normalized sonogram for bass module with rear driver up and rear driver down (don't get confused, in the first vertical sonogram the negative angles are up, in the second sonogram positive angles are up):
View attachment 160667
View attachment 160668
On the whole, this brings a slight improvement in the radiation. This is probably the better option.
The entire history of loudspeaker design is people imagining things that are audible and important and then spending enormous amounts of time implementing their ideas only to find that their design priorities are not supported by psychoacoustic research. Most of the 'errors' that designers seek to correct are things they see in measurements first, not from reported listener experiences. The history of technical 'issues' which designers seek to correct is exactly the same as the history of acoustical measurements. First they were obsessed with flat axial FR and bass Q, because that's all they could measure or model. Then in the 80s, you have software acoustic measurement and designers become obsessed with 'transient perfection' because it's one of the new things their tools showed them. More measuring tools create more imaginary issues and invented solutions.
Harmonic distortion and IMD is an example of this. Harmonic distortion is a crude metric that mathematically characterizes one simple type of deviation from an ideal signal. There is absolutely no reason to assume that it is audible except in extreme cases, and if it is audible, it is almost certainly the wrong metric to use to characterize the audibility. People have this intuition that orchestral music is 'complex' presumably because it has a lot of instruments, and this is more susceptable to IMD distortion, but let's be real. What is 'complexity'? A square wave has an infinite series of odd harmonics, is it 'complex'? The sound of a single familiar voice almost never sounds correct played back - is it 'complex'? Is IMD the correct metric to describe why your orchestral recordings sound like a cloudy soup? Unlikely.
A lot of audio designers clown audiophiles like Romy the Cat who has this very famous multiway horn system, all DIY, with a mishmash of exotic and unusual drivers such as a compression driver from the 50s, an english PA speaker for the bass, and a huge RAAL tweeter for the treble, all connected to passive line level crossovers and tube amps. And I would agree that it is not a cost effective way to create good sound - but consider the methodology. Romy the Cat doesn't 'suppose' something sounds bad due to measurements - he tries to make determinations about what he wants his system to sound like. He identifies the problem with the reproduction first, in his own experience and in his own terms. Then, he makes a change and listens to it.
There are obvious problems with this approach from an engineering perspective, but making assumptions about the importance of technical issues is not a shorter path to audio quality. Rick seems to want to bring the focus to audibility, but what do we really know about what performance metrics matter?
Lots of bass, user adjustable for quantity and to correct room issues. Smooth off axis without major resonances down to Schroeder. Narrow mid/treble dispersion less room-dependent than wide, but not necessarily better. What else does psychoacoustic research say about speakers?