Interesting find! These men have published a number of papers on electrodynamic loudspeakers.Actually, the problem of loudspeaker behavior at low levels is is scarcely studied and practically there is no papers on the topic. At least, I have no found systematic study when I was interested on the problem. However, I have found several interested articles. I remember interesting experimental study presented at the AES convention 126 by I.Djurek, A.Petosic and D.Djurek. The authors investigated the cone displacement at different levels and how suspension and spider influences it. Unexpectedly to me, they have observed, that at low signal levels (<1mA) the spider was unable to move due to residual strains and viscoelastic properties of the spider material. Thus, your assumption is not baseless. It seems, that under a certain conditions certain loudspeakers, actually, can behave quite complicated when they are driven by low dynamically changing signals.
This is one of those:
I am not sure if I got this right. As you emphasized "...two PhDs...", should this represent something like an opinion amplifier?
that don't make overkill system, okTDA 2009
Cool!
Two TDA 2009 for the mains and two in BTL for the sub
We will just have to disagree on this one. I think it is worth exploring.
To paraphrase a great guy - in God we belive, everyone else we verify.
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Thanks Dmitrij. Was it only when trying to make the spider move from still, or during every other "zero position" crossing?
Actually, the problem of loudspeaker behavior at low levels is is scarcely studied and practically there is no papers on the topic. At least, I have no found systematic study when I was interested on the problem. However, I have found several interested articles. I remember interesting experimental study presented at the AES convention 126 by I.Djurek, A.Petosic and D.Djurek. The authors investigated the cone displacement at different levels and how suspension and spider influences it. Unexpectedly to me, they have observed, that at low signal levels (<1mA) the spider was unable to move due to residual strains and viscoelastic properties of the spider material. Thus, your assumption is not baseless. It seems, that under a certain conditions certain loudspeakers, actually, can behave quite complicated when they are driven by low dynamically changing signals
Thanks Dimitrij.
Related to Ro8o8's post and now that it is free download:
ANSI/CEA-2034-A Standard Method of Measurement for In-Home Loudspeakers
A B revision will be out at the end of the year.
camplo, have you considered a two way like this: Denovo Audio HTM-12 with sub(s)?
I know it ain't AE...
Yah, I love CD's on waveguides. No more 1" domes for me
ANSI/CEA-2034-A Standard Method of Measurement for In-Home Loudspeakers
A B revision will be out at the end of the year.
camplo, have you considered a two way like this: Denovo Audio HTM-12 with sub(s)?
I know it ain't AE...
Yah, I love CD's on waveguides. No more 1" domes for me
It was conventional electrodynamic loudspeaker, but materials of the parts are not specified (total moving mass of the system is 14.8g).
As for silicone damped spiders, once I was triyng to measure Bl factor of loudspeaker having double silicone spider by adding a weight of known mass and measuring current through coil required to hold the cone in the rest position. I used laser position sensor to control the cone displacement. I was surprised how long the cone was relaxing to the rest position after I have added a weight (several hours !). This was the reason why I became interested in viscoelastic phenomena
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...and my comment is not really off topic as vinyl mastering induce mono-ed low end, giving a nice punchy sound to the vinyl masters versus the digital ones.
This is enhanced by the fact you can't limit as much with vinyl masters as you can in digital domain so overall vinyl mastering are often 'better' to the ears than digital one.
This is enhanced by the fact you can't limit as much with vinyl masters as you can in digital domain so overall vinyl mastering are often 'better' to the ears than digital one.
Thanks for sharing that interesting info and history.
Having a strong business/finance background, I'd call you lucky and wise, to have realized biz isn't where your heart/mind are, and not be tempted by it further. So many folks understandably trip up there...
It's awesome you have the math and coding skills to have mated crossovers design with polar measurements.
I really need to learn some more simulation skills, but i guess my passion is trial and error building, along with measuring...being one of those thickheads that needs to understand things in simple from the ground up terms...
The Q-Sys Designer software shown earlier continues to blow my mind with its capabilities. I've only begun to understand all the components that can be placed in a schematic.
One capability i really like for speaker development, is the ability to instantly switch designs. The changeover can be between entire speaker systems for usual a/b comparisons;
or even better, it allows instantaneous complete processor settings changeover. Like going from an IIR built crossover design, to a FIR design.
Allows real time FIR file exchange. Real time signal probing/tracing ..even lets you place dual FFT analyzers anywhere in the schematic.
And I haven't even got to the control side of q-sys yet, which allows conditional logic into a design. For instance, I can see trying to make an accurate, fairly continuous, level dependent, fletcher-munson EQ adjustment.
Actually, the problem of loudspeaker behavior at low levels is is scarcely studied and practically there is no papers on the topic. At least, I have no found systematic study when I was interested on the problem. However, I have found several interested articles. I remember interesting experimental study presented at the AES convention 126 by I.Djurek, A.Petosic and D.Djurek. The authors investigated the cone displacement at different levels and how suspension and spider influences it. Unexpectedly to me, they have observed, that at low signal levels (<1mA) the spider was unable to move due to residual strains and viscoelastic properties of the spider material. Thus, your assumption is not baseless. It seems, that under a certain conditions certain loudspeakers, actually, can behave quite complicated when they are driven by low dynamically changing signals
"Stiction" ~ Friction dynamics. At very low power inputs, the spider remains a source of non-linearity, more so with woofers with heavy moving masses and a strong spider.
Yes, "stiction" is the correct term and, as I said before, I have seen this before in a protype speaker, but that was a single case in thousands, so it remains to be seen if this is a common problem. I highly doubt that it is.
That said, I'll look at any data along these lines. It is an easy experiment to do. It's identical to the one that I did for amplifiers. You simply look at the Harmonic distortion spectrum on an FFT as you lower the signal level. (Mic very near the cone.) The harmonics will rise as the signal lowers if stiction is present. If you run into noise issue (the harmonics fall below the noise floor,) which is likely, then you can do some tricks to average down the noise and raise the harmonics out of it. I can describe that process although it takes some custom software to do it.
As of now however, we only have a few instances of this occurrence and no real data showing its significance. Without that we are all just guessing.
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Click on buy now button on the lower right. It will add to cart and then checkout. Yes, it is free, but you will need to create an account with minimal information. A user name, valid email address and phone number is required. If one is concerned about privacy, use a throwaway email account.
The standard was $103USD, but now free. It embodies the work of Floyd Toole and Sean Olive and others wrt how a neutral loudspeaker should measure (and sound). It also provides the basis for estimated in-room response calculation. I.e. providing a usefully accurate preview of how a given loudspeaker might perform in a typical domestic listening room. While the predicted curve is quite accurate, it cannot estimate the effects of room modes below transition/Schroeder. But we know how to take care of that
"Is it possible to cover the whole spectrum, high spl, low distortion with a 2-way?"
That simple question has a simple answer: No! Subwoofer(s) must be added, and the "ways" you divide up the audio spectrum to do so, is 3 or more, not 2. WHG
Given all this rational, why not build upgraded EV Pat4s? or Klipsch Jubs? A superb 3-way implementation is possible using today's technology if room corners are available in your listening space. WHG