Reading about this, it seems there are some obvious benefits of a cardioid midrange in terms of reducing reflections of the back wall, meaning we can potentially place the speaker closer to the back wall.
Gradient, Amphion and Dutch & Dutch seem to be among the only ones doing this.
So why not others?
Or in the world of DIY for that matter.
Gradient, Amphion and Dutch & Dutch seem to be among the only ones doing this.
So why not others?
Or in the world of DIY for that matter.
-the LXmini only produces a cardioid-like response between 700-900 Hz.
As to reducing reflections from the back-wall, it's easier to do a 3" thick pad of rockwool on the wall near the loudspeaker (assuming it's placed close).
Alternatively (wall-dependent), you could do an in-wall design.
IMO a cardiod for reducing back-wall reflections is not a great idea.
As to reducing reflections from the back-wall, it's easier to do a 3" thick pad of rockwool on the wall near the loudspeaker (assuming it's placed close).
Alternatively (wall-dependent), you could do an in-wall design.
IMO a cardiod for reducing back-wall reflections is not a great idea.
-well my post did have context, no? 
It's MUCH cheaper to do the absorptive panel on-wall than trying to integrate it into the loudspeaker design. IF you are truly concerned with back-wall reflections then an in-wall design is MUCH better.
Plus, there are (typically) significant detriments to having it in a design:
..substantial pressure loss creating: lower sensitivity (all-else-equal), higher resulting non-linear distortion,
..and added mechanical resistance (that tend's to reduce depth, design dependent).
That's not to say that I haven't recommended it in certain instances before, even recently as a design "notion" for a particular situation.
It's MUCH cheaper to do the absorptive panel on-wall than trying to integrate it into the loudspeaker design. IF you are truly concerned with back-wall reflections then an in-wall design is MUCH better.
Plus, there are (typically) significant detriments to having it in a design:
..substantial pressure loss creating: lower sensitivity (all-else-equal), higher resulting non-linear distortion,
..and added mechanical resistance (that tend's to reduce depth, design dependent).
That's not to say that I haven't recommended it in certain instances before, even recently as a design "notion" for a particular situation.
-well my post did have context, no?
It's MUCH cheaper to do the absorptive panel on-wall than trying to integrate it into the loudspeaker design. IF you are truly concerned with back-wall reflections then an in-wall design is MUCH better.
Plus, there are (typically) significant detriments to having it in a design:
..substantial pressure loss creating: lower sensitivity (all-else-equal), higher resulting non-linear distortion,
..and added mechanical resistance (that tend's to reduce depth, design dependent).
That's not to say that I haven't recommended it in certain instances before, even recently as a design "notion" for a particular situation.
Thanks for clarifying. Probably a good idea to have an absorptive panel on the back wall (by back wall I mean the wall behind the speakers) anyways. But WAF is low.
As I understand it, the cardioid approach cancels out sound radiation to the back and sides by some amount. Isn't this always a good thing?
Could you expand on the sensitivity loss?
I would think this was more of a bass issue and not a midrange one.
Problem with waveguides is that they typically have <90 degree dispersion, which means you need a large woofer to match the directivity at XO.
Hey defo, I think some of these opinions are a bit light on the data. probably the biggest problem is that its difficult to simulate this kind of enclosure. Probably possible with akbak but I'm not aware of anybody (publicly) doing it with a midrange.
might be possible to estimate this kind of enclosure with hornresp. but I dont think you'd be able to get away from just building some enclosures and actually measuring/tuning them.
Its easy enough to get sensitivity back with a better driver/larger/waveguide. so I dont really think thats a real problem. I'm with you. the idea sounds great. its getting good results thats the hard part.
Simulations of backside radiation and total directivity pattern are far from reality with midrange. With those wavelengths very small details of the baffle, driver's spider, frame and motor structure - interferences that they make - mess up ideal radiation pattern. Simulations suppose that radiator is a planar, symmetrical disc.
Dipoles and cardioids must be prototyped and meassured in 3-D. By doing those you gain experience for "an educated guess" of what will happen.
Dipoles and cardioids must be prototyped and meassured in 3-D. By doing those you gain experience for "an educated guess" of what will happen.
Except it requires about a quarter of a wavelength depth to effectively absorb and the first cancellation dip occurs at...
A cardioid radiation pattern not only greatly reduces the interaction with the wall behind the speakers it also puts a bit less energy into transverse room modes at frequencies above what can be treated by distributed subwoofers. These benefits come at the price of more cone area and complexity.
Agreed but it is simply not an option for many.
A simple but less common option is to place the woofer/s close to the wall, the midrange a significant distance from the wall and the crossover frequency so that the frequency of the cancellation dip for the woofer is in the midrange passband and the cancellation dip for the midrange is in the woofer passband.
Not too sure what you mean by in between. Something like a speaker in cupboard in an alcove? Or on a wall with a wide baffle and big chamfers? Or perhaps something else?
It is an interesting problem designing a speaker to work well on or near a wall which is where many speakers end up getting placed.
-well my post did have context, no?
Sure. But I was asking for the facts/science that produced your opinion, which your response was very light on.
Practical thicknesses of rockwool on the wall will have decreasing effectiveness as frequency decreases. Below a few hundred Hz, it may as well not be there.
Agreed that in-wall can be effective. But practical in most instances? Nope.
Again, interested to learn what basis these very vague statements arise from.
Not criticizing (yet
), just trying to learn.
-please note the title:
Why not cardioid midrange?
In this instance I'm treating "midrange" in the context of cardioid midrange loudspeakers.. which typically doesn't extend much lower than 400 Hz. (..of course if you need to go a bit lower then 4" instead of 3".. and if I remember correctly it starts running-out of effectiveness fast.)
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Again, interested to learn what basis these very vague statements arise from.
Not criticizing (yet
-you'll have to do a LOT of searching on that to get something more than "vague" then. ..and even then, you'll likely have to use common sense to extrapolate (..where you can find posts on real cardioid mid.s, but rarely with an equalized response and non-linear distortion results - so you'll just have to see what pressure drop (from the cardioid) and a resulting "boost" with eq. will do to non-linear distortion.)
Really, the only thing not proven is the subjective effect of adding resistance to a driver like this in the midrange. Subjective results are in general difficult to really "prove" at all.
Have you checked out the design and measurements of the Dutch & Dutch 8c?
I guess the definition of mid-range I had in mind (and D&D use) differs from yours: 100-1200Hz.
I have done lots of searching with good results, thanks. My only difficulty here is trying to understand what you're talking about - pressure drops, eq boosts, and non-linear-distortion - and how that relates topically.
I get the sense we have very different ideas in mind on how a cardioid is generated and what advantages/compromises they present.
Did you look at the measurements for the 8C?
If so, what did the non-linear graph represent? Why is it like that? What is different about that design from most, and why? (..connect the "loop" there and you'll have that answer on why the non-linear graph looks the way it does.)
-as far as understanding me, that's OK - Keyser didn't have a good time with it either (..even if he did go-on to create the 8C). ..and yes, you can search for that as well.
If so, what did the non-linear graph represent? Why is it like that? What is different about that design from most, and why? (..connect the "loop" there and you'll have that answer on why the non-linear graph looks the way it does.)
-as far as understanding me, that's OK - Keyser didn't have a good time with it either (..even if he did go-on to create the 8C). ..and yes, you can search for that as well.
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