More detailed response to Earl and "Vac" later, in the interim -
Yes, they have.
The mid driver based the structure "d" of this work is the 2164 and I think there was a successor with the same structure.
Prior to that, IIRC the 2227 bass driver (15") and an 18", the 2242 I think.
I can probably find more, why do you ask?
Best wishes
David
Yes, they have.
The mid driver based the structure "d" of this work is the 2164 and I think there was a successor with the same structure.
Prior to that, IIRC the 2227 bass driver (15") and an 18", the 2242 I think.
I can probably find more, why do you ask?
Best wishes
David
I was looking for some information on voice coil winding on both inside and outside of the former, could not find anything on the subject, so I was wondering whether there are some specific terminology to use for such searches. Has anyone come across any?
I also found somebody did patent a full ring conductive voice coil former design. I am quite sure this design had been done before because I had talked with a manufacturer whom had considered such design at least over 10 years ago, the same person involved also indicated he had a very flat impedance motor design.
I also found somebody did patent a full ring conductive voice coil former design. I am quite sure this design had been done before because I had talked with a manufacturer whom had considered such design at least over 10 years ago, the same person involved also indicated he had a very flat impedance motor design.
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I have always been a big Fane fan.
My first mobile disco set up was four Fane 12"-50WRMS speakers.
For their size they were very loud and sounded great.
I sold that disco and later built another one using Eminence speakers.
I was disappointed in the Eminence speakers as they just weren't as loud and didn't sound as good despite being more powerful wattage.
So I went back to Fane and have various Fane setups now.
For disco I like the Fane 12-250TC's.
For living room use I have a Fane 12-50WRMS in a folded horn cabinet working off a USB DAC.
My first mobile disco set up was four Fane 12"-50WRMS speakers.
For their size they were very loud and sounded great.
I sold that disco and later built another one using Eminence speakers.
I was disappointed in the Eminence speakers as they just weren't as loud and didn't sound as good despite being more powerful wattage.
So I went back to Fane and have various Fane setups now.
For disco I like the Fane 12-250TC's.
For living room use I have a Fane 12-50WRMS in a folded horn cabinet working off a USB DAC.
Thanks for the reply, I will take a little time to think some of the points over.
I have a few immediate comments
The paper #8989 was not about more cost effective ways.
He just adds extra cost elements to reduce the distortion even further.
As well as some use of the aluminium frame as a shorted turn and the usual aluminium piece inside the flux path there is a copper coil on the top plate plus a copper sleeve on the inner pole piece.
I note he has published, not just on transducer distortion but it's audibility.
Assessment of Nonlinearity in Transducers and Sound Systems — From THD to Perceptual Models
Measurements and Perception of Nonlinear Distortion—Comparing Numbers and Sound Quality
My university doesn't have these two, so I haven't read them yet, but I assume he wouldn't spend extra money on distortion reduction if he considered it fully under control.
Best wishes
David
I have a few immediate comments
The paper #8989 was not about more cost effective ways.
He just adds extra cost elements to reduce the distortion even further.
As well as some use of the aluminium frame as a shorted turn and the usual aluminium piece inside the flux path there is a copper coil on the top plate plus a copper sleeve on the inner pole piece.
I note he has published, not just on transducer distortion but it's audibility.
Assessment of Nonlinearity in Transducers and Sound Systems — From THD to Perceptual Models
Measurements and Perception of Nonlinear Distortion—Comparing Numbers and Sound Quality
My university doesn't have these two, so I haven't read them yet, but I assume he wouldn't spend extra money on distortion reduction if he considered it fully under control.
Best wishes
David
Dave,
Because they left out the information on the effect of just a single ring in the top plate, and I am just curious if secondary information like whether they implemented it in some of their drivers could point in the direction of what is in the missing info. So apparently they did. Thanks for mentioning this, will have a look at those drivers.
Vac
Because they left out the information on the effect of just a single ring in the top plate, and I am just curious if secondary information like whether they implemented it in some of their drivers could point in the direction of what is in the missing info. So apparently they did. Thanks for mentioning this, will have a look at those drivers.
Vac
Dave,
According to my Google and the information provided by JBL, both the 2227 and the 2242 only have a copper ring in the pole piece, not in the top plate. There appears to be a JBL 2106 according to one link I found, but this speaker apparently is based on a patent to have a thermal pathway from the driver to the rear of the enclosure. Nothing about a copper ring in the top plate.
Based on this, my provisional conclusion is that JBL has not implemented a copper ring in the top plate of any speaker they put on the market.
So, I come back to my earlier presumption: a copper ring in the top plate does not make much sense, because it is outside the magnetic field created by the VC.
To be more precise: in the absence of a copper ring on the pole piece, I would expect a copper ring in the top plate to have some effect. However, since a copper ring on the pole piece will be much more effective, the effect of a copper ring in the top plate will be negligible in case there is already a copper ring over the pole piece. Therefore, no manufacturer I am aware of has implemented a copper ring in the top plate.
According to my Google and the information provided by JBL, both the 2227 and the 2242 only have a copper ring in the pole piece, not in the top plate. There appears to be a JBL 2106 according to one link I found, but this speaker apparently is based on a patent to have a thermal pathway from the driver to the rear of the enclosure. Nothing about a copper ring in the top plate.
Based on this, my provisional conclusion is that JBL has not implemented a copper ring in the top plate of any speaker they put on the market.
So, I come back to my earlier presumption: a copper ring in the top plate does not make much sense, because it is outside the magnetic field created by the VC.
To be more precise: in the absence of a copper ring on the pole piece, I would expect a copper ring in the top plate to have some effect. However, since a copper ring on the pole piece will be much more effective, the effect of a copper ring in the top plate will be negligible in case there is already a copper ring over the pole piece. Therefore, no manufacturer I am aware of has implemented a copper ring in the top plate.
Alex's two papers do not speak to my points at all. They are extensions of the papers that Lidia and I did many years prior, and that is how to determine the perception of nonlinearities, in his case more specifically loudspeakers. But there is no mention of the audibility and the effectiveness of shorting rings.
Dynamics is just a word. But what I think people are describing in dynamic speakers is a lack of energy storage in the speaker itself. This is related to efficiency and how easily or "effortlessly" the speaker transmits sound into the air.
This would explain why both horns and arrays have good dynamics because of efficiency and lack of resonance. Multiple drivers and less flexing and stress per driver and also the coupling effect that increases efficiency (by <3db) as has already been discussed. Also large light weight cones with strong magnets and well braced heavy cabinets would all avoid energy storage issues.
I would be interested in seeing some decay plots of horns vs tweeters and dedicated subwoofers vs a typical 6" mid bass trying to play lower frequencies.
This is not necessarily mutually exclusive with the idea that dynamics are the ability to play loud and soft quickly. Something like a compression driver can do this because it is small and light weight and stiff and so probably has good energy release (aided by the horn) and so can start and stop on a dime.
Dynamics thus is a bit like a speakers agility. Starting, stopping, and getting power into the air efficiently all create dynamics. This would show up in CSD plots and maybe some other measurements of distortion. Internal energy storage and cone inertia and cabinet vibration would all work against it.
"Dynamics" is just a word, but then so is every other stated impression of sound quality. What this word needs is a concrete definition and a way to quantify it.
You suggest CSD, and perhaps one could glean "dynamics" from this, but my suspicion is that it can't or at least not the whole story. I fail to see anything in CSD that is not in the frequency response except in a few rare cases. There is a reason for this and that is because the frequency response and time response are intimately linked via the Fourier Transform. Thus, they are not separate things with one indicating something that the other cannot.
The one issue that I have seen where one would not guess correctly the CSD from the FR is when there are two resonances close together such that in the steady state they tend to cancel, creating a dip, but as they ring out they become separate resonances. This is not readily apparent from a single FR curve, but it is also fairly rare and I don't see this rare effect as having the aspects of "dynamics".
It seems then that the issue is how to objectively measure "dynamics" so that various designs can be compared. To me MaxSPL and its headroom above NormalSPL for a speaker would be a big part of this, but that's still not very well quantified.
You suggest CSD, and perhaps one could glean "dynamics" from this, but my suspicion is that it can't or at least not the whole story. I fail to see anything in CSD that is not in the frequency response except in a few rare cases. There is a reason for this and that is because the frequency response and time response are intimately linked via the Fourier Transform. Thus, they are not separate things with one indicating something that the other cannot.
The one issue that I have seen where one would not guess correctly the CSD from the FR is when there are two resonances close together such that in the steady state they tend to cancel, creating a dip, but as they ring out they become separate resonances. This is not readily apparent from a single FR curve, but it is also fairly rare and I don't see this rare effect as having the aspects of "dynamics".
It seems then that the issue is how to objectively measure "dynamics" so that various designs can be compared. To me MaxSPL and its headroom above NormalSPL for a speaker would be a big part of this, but that's still not very well quantified.
Its not just total loudness, which is more a matter of avoiding heat damage. Its more the ability to go loud fast, which means shedding the kinetic energy. CSD isn't the whole story but l'd imagine horns do have quick decay, as do ribbons, within their own target band. I wasn't aware that CSD is linked to frequency response, I know cabinet noise often isn't and that is a form of energy storage.
I would also think that the less wide a band a driver has to cover the better the energy transfer.
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I don't think that "shedding the kinetic energy" has much meaning scientifically so I would hate to use it in a definition of "dynamics".
Also, CSD is derived from the impulse response and the impulse response is the Fourier Transform of the frequency response, so yes, the two things are intimately related.
Cabinet noise is part of the system response and the impulse response so it too is completely tied to the frequency response through the same transform. These are topics which people get wrong all the time. I think that it is important to clear them up.
Also, CSD is derived from the impulse response and the impulse response is the Fourier Transform of the frequency response, so yes, the two things are intimately related.
Cabinet noise is part of the system response and the impulse response so it too is completely tied to the frequency response through the same transform. These are topics which people get wrong all the time. I think that it is important to clear them up.
Is it wrong to examine a speaker by depicting an impulse response unless the impulse is band-limited to the speaker's intended bandwidth?
Is it ever done that way?
I suppose it wouldn't matter with a waterfall display based on a freq sweep. Or would it?
B.
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Well, I'm facing the question of assessing SQ in my home trials. Not getting far.
With square waves, you wouldn't expect a woofer to have sharp corners on a scope of its output. So why would you test a woofer for reaction to an "infinite" impulse? Wouldn't you use a band-limited impulse because that's all the woofer is supposed to manage?
Is a group-delay plot an image of what the cone is supposed to be doing?
B.
I don't know that much about how the measurements are derived. But the concept of shedding energy is important. If you take something like a race car for example, if you lower the reciprocating mass of the engine and drive train and mass of car itself, it will more quickly convert the energy into motion.
I'm saying that what I think dynamics is is the transfer of energy into the air quickly and efficiently. Maybe this is a bit of a colloquial explanation. I'm not sure how this would be properly scientifically measured, but as a concept it certainly exists.
Two things that occurred to me are that multiple drivers and horn loading both reduce excursion at a given spl. This means less velocity which means more rapid and responsive movements of the cone itself.
I wasn't aware of such a huge dynamic range on something like a piano. Thanks for the post.
Hi Ben;
Isn’t a perfect impulse defied as having all frequency/infinite energy in zero time?
No woofer could follow it and no tweeter could survive it. Would driving the transducer into non-linearity with a signal like that give meaningful data?
I think the impulse response derived from a frequency sweep is more like you were thinking being band limited, theoretically.
All in all aren’t we attempting to know how well the driver follows the signal?
Barry.
Isn’t a perfect impulse defied as having all frequency/infinite energy in zero time?
No woofer could follow it and no tweeter could survive it. Would driving the transducer into non-linearity with a signal like that give meaningful data?
I think the impulse response derived from a frequency sweep is more like you were thinking being band limited, theoretically.
All in all aren’t we attempting to know how well the driver follows the signal?
Barry.