Objections to speaker qualifications

[Jim Taylor]

Sure, but isn't the lobing diagram just a 2D / 3D representation of interference in space, while a comb filtered FR is a representation of interference at a single point in space across multiple frequencies?

Yes. That was the second diagram. I'll edit my post to make the second link more obvious.

Jim

 

[amirm]

An example is the large MBL's, the most advanced technology available in speaker design today, not coaxials (old tech with some improvements by Kef) which seem to have taken over the market.

I have listened to MBLs countless times as they are at every audio show. On content that is supposed to be spacious, they sound excellent. On content that is not, e.g. studio mixed, they again make that sound spacious which is quite wrong. So unless you only listen to type of speaker where such added effect is fun, they not a general purpose speaker.

 

[Titurel]

If you’d like to propose a more comprehensive and/or more precise definition, please do so.

Perhaps you might consider publishing a gloss of forum specific definitions for words with real world meanings, so us newbies can avoid offending.

 

[Theta]

? Which are...?
Lobing is the first thing. What is the second thing?


If the drivers are working in the same frequency band (I don't know if it is true for this loudspeaker), than the comb-filtering is the only problem. Obviously, you are confusing lobing with comb-filtering.


No. LIne source speakers made from several drivers working in the same frequency band has no lobing. It has comb-filtering only (in the same frequency band).
Only if this line source is combined with other driver(s) working in the other frequency band (divided by crossover), than the lobing is created.
Obviously, you are confusing lobing with comb-filtering.


"Eliminate" and "Disqualify" are too strong word - I would say "that loudspeaker potentially has BIG problems". For example, look at the McIntosh XRT2.1K loudspeaker:

View attachment 379891

It has lobing between the two 6.5" drivers and the line array in front of them. And between the two 6.5" drivers and the other six 8" woofers. Period.
Whether the lobing is small or anaceptable big, depends on the exact crossover frequency and the exact distance between them.
About the comb-filtering here - I don't know if the 2' drivers and 3/4 tweeters are shaded or not.


Every conventional 2-way, 3-way, 4-way, ... has lobing. So, yeah, pretty common problem... and acceptable, if not too big.



Wrong! Klippel never said that!
Sitting on a chair with tweeter at ear level is how 99.9999999 % of all humans on earth are listening to music in their homes - it is convenient and relaxing. And all of those humans are moving with their heads when listening - what is the problem with that?
I am really curious - how are you listening to your loudspeakers (and which are they)?

For a reference point at ear leveI listening: tri-amplified Yamaha NS1000. OK but very constraining.
For omni-directional: Duevel Venus, not state of the art but very enjoyable. Looking for better on both count.

 

[pablolie]

MBL's aren't true omni. They are at best axially symmetric in the horizontal plane, but are definitely not vertically. And what qualifies them as "the most advanced technology"?

The term Dr Jack Oclee-Brown uses for coaxial driver is coincident source, not point source, meaning that the acoustic centers of the lower frequency driver and the higher frequency driver are (approximately) coincident. The advantage of coax drivers is that the horizontal and vertical dispersion is similar, with the absence of lobing (or significantly reduced lobing in the case of 3 or more ways with separate woofers) in the vertical plane.

I'd like to 10x like this post.

 

[Blumlein 88]

For a reference point at ear leveI listening: tri-amplified Yamaha NS1000. OK but very constraining.
For omni-directional: Duevel Venus, not state of the art but very enjoyable. Looking for better on both count.

You listen with NS1000s from Yamaha???

As for the Duevel Venus, Positive Feedback said it worked great on a Shelby Lynne homage to Dusty Springfield. What else does anyone need to know right? And still some comments on the review raised some factual questions.....those bloody trolls.

 

[Theta]

I have listened to MBLs countless times as they are at every audio show. On content that is supposed to be spacious, they sound excellent. On content that is not, e.g. studio mixed, they again make that sound spacious which is quite wrong. So unless you only listen to type of speaker where such added effect is fun, they not a general purpose speaker.

I can't argue with that, since studio mixed recordings is most people's reference. You kind of nailed it, as my reference is musician playing live which is very rare in studio .
But all the serious R&D, investment, and difficulty in manufacturing those Melon drivers, just to make a "fun" speaker?

 

[Theta]

You listen with NS1000s from Yamaha???

As for the Duevel Venus, Positive Feedback said it worked great on a Shelby Lynne homage to Dusty Springfield. What else does anyone need to know right? And still some comments on the review raised some factual questions.....those bloody trolls.

Yes Tri-amplified NS1000, is that bad?
Funny you should mention that Shelby Lynn recording. I actualy went to Shelby Lynn's live performance of that homage in Los Angeles, but never read that positive feedback review.

 

[tmtomh]

Perhaps you might consider publishing a gloss of forum specific definitions for words with real world meanings, so us newbies can avoid offending.

No offense taken - I was commenting on the utility, or lack thereof, of posting 3 or 4 or however many comments all saying the same thing that no one disagrees with ("there is no such thing as a true/absolute point source").

Perhaps you might consider not deflecting and instead just say what you have in mind as a useful working/practical definition of a point source or quasi-point source, given that a pure point source is not a thing.

 

[Theta]

No offense taken - I was commenting on the utility, or lack thereof, of posting 3 or 4 or however many comments all saying the same thing that no one disagrees with ("there is no such thing as a true/absolute point source").

Perhaps you might consider not deflecting and instead just say what you have in mind as a useful working/practical definition of a point source or quasi-point source, given that a pure point source is not a thing.

A microphone in reverse

 

[stoo23]

A microphone in reverse

Both AKG & Sennheiser produced specific Microphones that could perform that task.

 

[Blumlein 88]

A microphone in reverse

Are you taking into account omni, cardioid, figure 8 (ribbon or condenser) etc when you say this? Should we listen to ribbon recordings with panel speakers, omni with omni speakers, cardioids with most speakers which are something like a cardioid?

 

[MAB]

A microphone in reverse

Yes, you split this hair in your original post.
And continue to beat this dead horse, while we all watch.

 

[tmtomh]

A microphone in reverse

So you're proposing that only a speaker system with a full-range driver is a point source? I presume this speaker would also have to be in a sealed enclosure and not ported, yes? (EDIT: see @Blumlein 88 's comment just above for more along the same lines I'm raising here.)

That would fail the criteria in the question I posed that a working definition be useful and practical.

So then what are you arguing that we should call speaker systems that have two or more coaxial drivers?

 

[Titurel]

No offense taken - I was commenting on the utility, or lack thereof, of posting 3 or 4 or however many comments all saying the same thing that no one disagrees with ("there is no such thing as a true/absolute point source").

Perhaps you might consider not deflecting and instead just say what you have in mind as a useful working/practical definition of a point source or quasi-point source, given that a pure point source is not a thing.

You misread me. I wasn't deflecting. I was, until your intrusion, having a pleasant chat with (responding to) one of the other posters. Then, I simply suggested that someone both more motivated and more technically up to date, than I, might come up with such a metric.

 

[tmtomh]

You misread me. I wasn't deflecting. I was, until your intrusion, having a pleasant chat with (responding to) one of the other posters. Then, I simply suggested that someone both more motivated and more technically up to date, than I, might come up with such a metric.

Fortunately for everyone, we don't have to depend on your determination of what's an intrusion and what's a contribution to the discussion. If you're only motivated to allege a problem and can't be bothered to propose a remedy, then I think folks can draw their own conclusions about the utility of your pleasant chatting.

 

[stoo23]

May I humbly suggest, ... that a 'Point Source' is, by definition a 'Point', invariably a Single Point, not multiple. So it would be rather incorrect to define a device with More than one source of emanation, as a 'Point Source' ,.... Perhaps a Tannoy or similar dual concentric, mounted on an 'Infinite Baffle'

 

[Blumlein 88]

May I humbly suggest, ... that a 'Point Source' is, by definition a 'Point', invariably a Single Point, not multiple. So it would be rather incorrect to define a device with More than one source of emanation, as a 'Point Source' ,.... Perhaps a Tannoy or similar dual concentric, mounted on an 'Infinite Baffle'

How many angels can dance on the point?

 

[stoo23]

You'll Have to ask Paul Kelly about that

 

[NTK]

"Point source" is a concept in the analysis of waves, which includes acoustics. Any sound source can be approximated as a point source when the observer is in the far field. It allows certain simplifications in the mathematical analyses. (The >1 wavelength criterion below is just one criterion, another is that the distance from the observer to the sound source is >2-3x the largest dimension of the sound source.)

Source of the screen clip: https://community.sw.siemens.com/s/...ee-versus-diffuse-field-near-versus-far-field