Shootout between JBL M2 and Revel Salon 2

[watchnerd]

So a speaker system that controls its output so that the directivity in the bass is no longer omni but, say, cardioid, must not be called "controlled directivity"?

BS

If you want to argue about the common definition of controlled directivity and what it usually refers to, you'll need to start with editing dozens of AES papers dating back to 1973.

 

[Cosmik]

Keith, you don't get to redefine acoustic terms of art just to suit your own purposes.
Directivity refers to managing reflection and diffraction patterns above the Schroeder frequency.

So if the room was huge you wouldn't have "controlled directivity" at all?

To me, this looks like the the hijacking of a general term "directivity" by people whose noses are out of joint because they never thought of the idea of using DSP and multiple drivers to control directivity in the bass!

Mr. Linkwitz summarises the Kii Three thus on his "Constant Directivity" page:

Controlled Directivity: 4.8dB (80Hz - 1kHz, slowly rising thereafter)

so he does not refer to the presence of the room or its size at all.

 

[Purité Audio]

What a manufacturer calls it is immaterial, the cardiod response of the Kii's and Beolabs and Dutch&Dutch 8C ( different technically ) improve sound quality which is corroborated by measurement, it really is that simple.
I fully expect every manufacturer to copy these designs if they can bring together the technical skills necessary.
They are the future.
Keith

 

[Cosmik]

What a manufacturer calls it is immaterial, the cardiod response of the Kii's and Beolabs and Dutch&Dutch 8C ( different technically ) improve sound quality which is corroborated by measurement, it really is that simple.
I fully expect every manufacturer to copy these designs if they can bring together the technical skills necessary.
They are the future.
Keith

A simple "thanks" (and maybe a 'like'?) would have been sufficient.

 

[Purité Audio]

The plain brown envelope is in the post.
Keith

 

[Jakob1863]

@watchnerd,

Two points:

1. Yes, manufacturers are doing sophisticated things to reduce bass nodes in localized areas and to mitigate boundary effects (not just in the bass). However, calling this "directivity control" conflates the activity with "controlled directivity speakers", which is primarily concerned with a very different phenomenon, namely that of addressing above-the-bass reflections off walls, objects, etc.

If for no other reason to avoid confusion, a different term should be used.

2. Applying phasing effects to reduce the bass by 6 dB - 10 dB behind the speaker will reduce the boundary effect, but the wavelengths involved are > 2.9 meters / 9.4 feet, making them above the beaming frequency of any normal driver and thus tending towards omni (as gated by baffle width). And, again, the primary acoustic problem with sub-Schroeder frequencies isn't directivity, but room nodes, so calling it 'directivity' is just confusing and isn't speaking to the main problem.

I think i understand what you´re after, but at the same time you seem (if i got it right) to advocate the correct use of terms of technical acoustics.
As the socalled "directivity index" describes the relation between the radiation of an assumed ideal omnisphere to the actual measured loudspeaker in the technical definition there is no frequency bandwidth restriction included.

Given that the assumed omnisphere is radiating the exact same amount of energy in every direction at every frequency it follows that any attempt to depart from that behavior is "directivity control".

But it still describes a virtue of the specific loudspeaker that still is given if you would use it in free space.
In contrast you argue with the different ramifications if loudspeakers are used in rooms, which is true but does not change the directivity index of the loudspeaker.

If you want to argue about the common definition of controlled directivity and what it usually refers to, you'll need to start with editing dozens of AES papers dating back to 1973.

I don´t think so, as derived from the definition of the directivity (index) the perfect, albeit unobtainable, controlled directivity or constant directivity would be the exact same difference (compared to the assumed ideal omnisphere) over the whole frequency bandwidth if measured under a specific angle.

 

[dallasjustice]

I know a guy who said he prefers to have a wooden box filled with kitty litter and an antenna attached to it and his system which creates distortion. In fact, there's a lot of people who prefer it.

jtwrace, please don't feed the trolls.
Simpler just to put them on your ignore list than to listen to the bull schitt.

 

[12B4A]

What a manufacturer calls it is immaterial, the cardiod response of the Kii's and Beolabs and Dutch&Dutch 8C ( different technically ) improve sound quality which is corroborated by measurement, it really is that simple.
I fully expect every manufacturer to copy these designs if they can bring together the technical skills necessary.
They are the future.
Keith

I think the future will be a pseudo-tension between controlling bass nodes at the speaker level via its radiation pattern and controlling bass unevenness at listening positions via system level processing to multiple speaker positions. I think the system level solution will be preferred for multi-channel applications while 2-channel folks will gravitate towards the speaker level solution.

 

[Sal1950]

I know a guy who said he prefers to have a wooden box filled with kitty litter and an antenna attached to it and his system which creates distortion. In fact, there's a lot of people who prefer it.

These types of problems sadly effect millions of US residents alone.
"A mental disorder, also called a mental illness[2] or psychiatric disorder, is a behavioral or mental pattern that may cause suffering or a poor ability to function in life. Such features may be persistent, relapsing and remitting, or occur as a single episode. Many disorders have been described, with signs and symptoms that vary widely between specific disorders.[3][4] Such disorders may be diagnosed by a mental health professional."

 

[dallasjustice]

The "I know a guy" rhetorical device is still undefeated on audio forums.

These types of problems sadly effect millions of US residents alone.
"A mental disorder, also called a mental illness[2] or psychiatric disorder, is a behavioral or mental pattern that may cause suffering or a poor ability to function in life. Such features may be persistent, relapsing and remitting, or occur as a single episode. Many disorders have been described, with signs and symptoms that vary widely between specific disorders.[3][4] Such disorders may be diagnosed by a mental health professional."

 

[DonH56]

Hmph. Maybe we should just rename all the speaker threads "Kii and B&O vs. xyz" and be done with it?

Directivity is one of many terms that practical usage has corrupted and mostly superseded the original "pure" definition.

 

[RayDunzl]

Hmph. Maybe we should just rename all the speaker threads "Kii and B&O vs. xyz" and be done with it?

What about Dutch & Dutch?

They're better than everything else too...

 

[Purité Audio]

It is rather a shame that US speaker manufacturers are technically rather lacking, perhaps a stern talking to is in order?
Keith

 

[Mivera]

It is rather a shame that US speaker manufacturers are technically rather lacking, perhaps a stern talking to is in order?
Keith

Much better audio from Europe. Most North American crap is made in China anyways. I'm hoping Trump brings the audio back.

 

[Fitzcaraldo215]

What about Dutch & Dutch?

They're better than everything else too...

Of course they are better. Keith carries them, does he not?

 

[Sal1950]

Of course they are better. Keith carries them, does he not?

Yea,, but too bad the listening tools in his closet aren't powerful enough to make sound decisions. (pun intended). LOL

 

[Purité Audio]

God bless America

 

[Wayne]

It is rather a shame that US speaker manufacturers are technically rather lacking, perhaps a stern talking to is in order?
Keith

How do Vandersteen speakers compare to those commonly discussed on this forum, ie Kii, JBL, etc? Are they worlds apart or similar in sound quality?
Thanks

 

[A.wayne]

I concurred with some comments in the AVS thread about panel speakers. Someone said they preferred panels in stereo, but found them poor and uninvolving in mono. I agree. I have owned 7 different panel speakers over the years. I have considerable time spent listening to about twice that many owned by friends. I've the curious experience that mono recordings over a pair of panels is great. A mono recording over one panel is not so great. A really good box speaker in mono using only one speaker seems much better.

Now it makes me wonder about the Harman testing of panels in mono. Yet I am not sure where it should stand. It is also true that most panels have rather poor frequency response. You would expect that to hurt it in mono. The directivity issues and dipole nature also get swallowed up some when you mix all that from two sources in ways it will not listening to one.

Then I have this experience. At one time I put one Soundlab on one channel, and one well regarded box speaker on the other channel. Used my Tact room correction to run the test signals and develop correction curves just that way. A wildly different curve of correction between the channels. The correction was good enough you heard nothing obviously amiss. Imaging, which I thought would suffer badly, instead sounded fine. It did not quite seem like either speaker, but it wasn't all messed up or wavering up and down the frequency band. It actually was one of those experiences that kept pricking my audiophile mind about how highly discriminating (or not) our hearing was. The room correction impressed me, and impressed upon me that your hearing wasn't that hard to fool. That keeps me skeptical when people who know more than me tell me it isn't a good idea to correct above the Schroeder frequency. I actually tried that at the time. Without correction above 500 hz it was just about the mismatched mess you would imagine.

So I sound like an audiophool this way, but I wonder if there isn't something about panel dipoles in mono that alter that spin-o-rama vs listener preference correlation curve. Yet the little data I have read about seems like the measured panel results of strange directivity and uneven FR predict just about how poorly they do in the blind testing. My experience correcting panels indicates a greatly improved listening experience yet I can't correct for the directivity issues. Plus the several Harman speakers I have heard since getting cued into their design method have simply out-performed anything close at all to their price. And as a lifelong panel guy, I don't miss the panels. The panels still have attributes I prefer, but on balance Harman seems to be onto something important.

You cant test a dipole speaker with anything close to it , the speaker will interact and you will havd phasing issues.

This kind of testing and i have always maintained this position, is absolutely rigged to give the best outcome to the home team ...


Regards

 

[DonH56]

I suppose the good news is that I can cross this thread off those I watch and just go downstairs and listen to them. Once I get over this durn cold/flu/whatever junk I've got...