Klipsch R-41M Bookshelf Speaker Review

[tuga]

Resonances :
Would be interesting to see measurements of thin walled speakers (Few low price speakers are already tested) by clamping them with heavy planks/makeshift CLD of suitable materials. Isn't it ?

Not to me. I'm only interested in advanced "thin-walled" cabinets such as those designed by the BBC, not cheaply-built rubbish.

Factors in the design of loudspeaker cabinets
H.D. Harwood, R. Matthews - January 1977


The mechanical properties of timber, wood products and other materials potentially suitable for the construction of loudspeaker cabinets have been measured and details of the results are given. Various commercially available damping materials have also been assessed and their relative efficiencies are listed. A new method of test for the cabinets of completed loudspeakers has been devised and a tentative performance specification has been produced.

http://downloads.bbc.co.uk/rd/pubs/reports/1977-03.pdf

 

[Frank Dernie]

You might be assured you can hear it, but I bet you won’t have the assurance that it is invisible on the spinorama.

I don't doubt for a moment that both the sound being radiated by the cabinet and that being radiated by the drivers will both be combined in a spinorama. What I have yet to have to have understood is if they can be separated using just that data and if so how, and whether it matters.
I have confidence that the cabinet radiation is an important aspect of the SQ of a speaker. Having a "goodness" selection method that doesn't adequately take it into account seems a bad idea to me.
I am an amateur when it comes to speakers but through noise and vibration research I met people for whom it has been a life's work.
The most experienced of them tells me he predicts cabinet radiation using FEA and confirms on the prototypes using laser vibrometer. He tells me there isn't another way to do it accurately.
I believe him, so unless somebody can tell me how the effect of this aspect of loudspeaker shortcoming can be derived from the spinorama I am far from convinced it is the whole picture.
Yes I see the Harman research shows preference for certain shape of spinorama but would two speakers having similar spin profiles where one has an inert cabinet and another a lively one be equally favoured?
It seems unlikely to me so this data is not enough to score speakers IMHO, or I have yet to be convinced that it is.

 

[tuga]

The research on audibility of resonances I linked to was conducted when @Floyd Toole was at the Canada National Research Council, not Harman.

Isn't the NRC about state-funded industrial research?
Surely the goal is at least partly commercial profit.

The National Research Council of Canada (NRC) is Canada's largest federal research and development organization.

The NRC partners with Canadian industry to take research impacts from the lab to the marketplace, where people can experience the benefits. This market-driven focus delivers innovation faster, enhances people's lives and addresses some of the world's most pressing problems. We are responsive, creative and uniquely placed to partner with Canadian industry, to invest in strategic R&D programming that will address critical issues for our future.

Each year our scientists, engineers and business experts work closely with thousands of Canadian firms, helping them bring new technologies to market. We have the people, expertise, services, licensing opportunities, national facilities and global networks to support Canadian businesses.

https://nrc.canada.ca/en/corporate/about-nrc

 

[QMuse]

Any factory research is biased to support factory benefits.

True, but that in no way contradicts the fact that factory researches help production of high quality products from which customers will benefit too.

 

[BDWoody]

These returns are expected and factored in the business expenses. Don't feel sorry for Costco. Not that I approve it.

I feel sorry for the people who somehow justify to themselves this type of stealing.

I'm no Costco, but as a small business owner, dealing with dishonest customers gets old, and expensive quick.

 

[tuga]

True, but that in no way contradicts the fact that factory researches help production of high quality products from which customers will benefit too.

Quality can refer to many things: build quality, reliability, consistence of performance.

I think many of us are questioning how listener preference can be linked to performance, or the accurate transduction of the recorded signal.
With a TV display it's easy beacuse the reproduction is made on a flat surface but speakers spray sound into a room.

Is it meaningful to use a selection of listeners of varied experience asked to express their taste (I find the word preference a bit too pompous) to determine which dispersion patter and tonal curve is the most accurate?

 

[tuga]

No doubt a considerable undertaking but it would probably be beneficial to move this discussion about research based on listener preference vs. high fidelity to its own topic.

 

[QMuse]

Floyd Toole post on avsforum:

Originally Posted by Gooddoc
It was my understanding that resonances are captured in the spins as FR abnormalities that carry through the measurements. It's what a resonance would do, so if you don't see it, then it's not there.


Thanks Gooddoc, you anticipated my response.

Resonances originate in transducers, in mechanical resonances in enclosures, and in acoustical resonances in enclosures. They all exhibit themselves in anechoic measurements and if they are energetic enough we hear them. This 29 year old paper explains it all in great detail:
Toole, F.E. and Olive, S.E. (1988). “The modification of timbre by resonances: perception and measurement”, J. Audio Eng. Soc., 36, pp. 122-142.

Putting an accelerometer on the wall of a cabinet is not a reliable indicator of the audibility of a resonance (sorry John Atkinson). For example, some panel resonances radiate sound effectively and others do not, but both exhibit vibration at a point on the panel. Harman and other advanced designers use scanning laser vibrometers to reveal patterns, polarity and amplitude of panel movement which guides the placement of structural reinforcements to reduce acoustical radiation from the resonance. When it is below the audible threshold in the anechoic frequency responses all is well (see the paper, or my books). It is not necessary to have foot thick concrete enclosures to eliminate audible resonances, good engineering can do it in rectangular wooden boxes.

Box shape is a factor, but a small one. Internal resonances are easily damped with fluff. Curved surfaces can be beneficial, or not, depending on how they fit into the total structure. Mostly it is a visual aesthetic issue, part of the industrial design, and having something to say in the literature, whether it affects the sound or not.

 

[Sgt. Ear Ache]

If I'm not mistaken that particular reference is mostly about frequency response and I completely agree that frequency response dominates. Should we ignore other factors?
Preference is taste; it doesn't have a direct relationship with acuracy.
Preference is useful for a manufacturer for marketing reasons. The average consumer probably only cares about how low and how low, perhaps tonal balance. Audiophiles are or should be a bit more demanding, and expect more than just flat frequency response.

"audiophiles" are included amongst the many people who's preferences have been tested. Why do you keep ignoring that? And why exactly should an audiophile expect (or even want) a colored frequency response?

 

[Frank Dernie]

If that is so allow me to have some reservations here as phase issues don't really have reputation to be audible.

I did experiments on the audibility of phase error about 45 years ago. The speakers I was using were not phase coherent (most weren't then and still are not) but I could not hear any change due to phase shift, whereas the oscilloscope signal was very, very different. An important lesson for me at the time

 

[Hiten]

Not to me. I'm only interested in advanced "thin-walled" cabinets such as those designed by the BBC, not cheaply-built rubbish.

OK.
- - - - - - -
the cheap speakers choice was intentional to differentiate if difference/s are significant or not. As I guessed they will produce more pronounced resonances. I dont know I may be right or wrong.

 

[QMuse]

I did experiments on the audibility of phase error about 45 years ago. The speakers I was using were not phase coherent (most weren't then and still are not) but I could not hear any change due to phase shift, whereas the oscilloscope signal was very, very different. An important lesson for me at the time

LOL

Recently I was so proud when I adjusted phase of my speakers via room EQ. All those time domain graphs are looking so much better now that I have fixed them. And then I switched phase correction off leaving only amplitude correction active to hear the difference. I wasn't able to hear any.

P.S. There was one exception: once I corrected phase difference between speakers bass cancellation in the 80-100Hz range was gone and that was audible.

 

[tuga]

"audiophiles" are included amongst the many people who's preferences have been tested. Why do you keep ignoring that? And why exactly should an audiophile expect (or even want) a colored frequency response?

A considerable amount of audiophiles, maybe half, consistently or recurrently buys "coloured" gear: tube amplifiers, vinyl, flavoured speakers.
This is their preference taste. Or are they being fooled by their sighted bias?

 

[q3cpma]

After reading all of this, I agree on one point: resonances induce frequency response and sound power high Q spikes, but these aren't equivalent: if you use a PEQ to make a very high Q dip, there are good chances you won't hear it, but resonances like the one in the JBL 705p (see soundandrecording and SOS) are still audible. Basically, what I want to say is that time domain anomalies might show in the frequency domain, but that doesn't mean you can completely ignore the time domain; especially decay, since group delay isn't that important, but used by frequency fanatics as a strawman to completely disregard time domain examination.

tl;dr resonance => high Q dip/spike but !(high Q dip/spike inaudible => resonance inaudible)

 

[q3cpma]

A considerable amount of audiophiles, maybe half, consistently or recurrently buys "coloured" gear: tube amplifiers, vinyl, flavoured speakers.
This is their preference taste. Or are they being fooled by their sighted bias?

There is a lot of sighted bias, but the main question is: are you talking about ear preference or mind preference? Because I think this is just retro-LARPing, and people who actually had to deal with vinyl and tubes without any choice are very happy we progressed.

 

[QMuse]

After reading all of this, I agree on one point: resonances induce frequency response and sound power high Q spikes, but these aren't equivalent: if you use a PEQ to make a very high Q dip, there are good chances you won't hear it, but resonances like the one in the JBL 705p (see soundandrecording and SOS) are still audible. Basically, what I want to say is that time domain anomalies might show in the frequency domain, but that doesn't mean you can completely ignore the time domain; especially decay, since group delay isn't that important, but used by frequency fanatics as a strawman to completely disregard time domain examination.

tl;dr resonance => high Q dip/spike but !(high Q dip/spike inaudible => resonance inaudible)

Decay is much more affected by the room you're listening in than by speaker's own decay characteristic. Here room treatment and EQ will be of great help but unfortunately only a small number of audio enthusiast has done it properly. Yet many of them are willing to brag all day about CSD graphs.

 

[Sgt. Ear Ache]

A considerable amount of audiophiles, maybe half, consistently or recurrently buys "coloured" gear: tube amplifiers, vinyl, flavoured speakers.
This is their preference taste. Or are they being fooled by their sighted bias?

largely, yes. And also, what a "considerable" amount of audiophiles buy is really only meaningful if they also continue to prefer those colored flavors in blind tests...which they apparently don't...just like the fact that a "considerable" amount of the general public continues to buy bluetooth speakers and HTIAB kits but still ALSO have the same speaker preferences as the golden-eared audiophiles in speaker preference tests. The fact is, we are all humans and it turns out we all mostly like the same shit. Audiophiles are not special in any regard...

 

[q3cpma]

Decay is much more affected by the room you're listening in than by speaker's own decay characteristic. Here room treatment and EQ will be of great help but unfortunately only a small number of audio enthusiast has done it properly. Yet many of them are willing to brag all day about CSD graphs.

I completely agree, but something like this (at that frequency) will go over the room:

 

[QMuse]

I completely agree, but something like this (at that frequency) will go over the room:

Are you are referring to the artifact happening at 800Hz? While esthetically it looks very intriguing it translates to a narrow dip at FR which would be completely inaudible. As for the tone itself that would be lingering a little longer than others, that would be masked by other content.

There is probably a huge phase anomaly at the same frequency as well, but it seems that our hearing system simply doesn't pay attention to such things.

 

[q3cpma]

Are you are referring to the artifact happening at 800Hz? While esthetically it looks very intriguing it translates to a narrow dip at FR which would be completely inaudible. As for the tone itself that would be lingering a little longer than others, that would be masked by other content.

There is probably a huge phase anomaly at the same frequency as well, but it seems that our hearing system simply doesn't pay attention to such things.

I don't think you've read my first post. The dip is inaudible, but not the time anomaly. See https://www.soundonsound.com/reviews/jbl-7-series and https://www.audiosciencereview.com/...ty-jbl-705-i-speakers.8564/page-5#post-265573