Audio Misconceptions?

[MBauer]

Further amplification

The delay to which you are now referring is propagation delay, and it decreases as the medium density increases. The physical delay at the pratically applied frequencies, from the center to edge of a midrange, for example, is not of a degree that is perceptually relevant within the context of hearing an actual delay. The resonances in a transducer diaphragm are classified as non-delayed resonances. The important issue[aspect] is the non-linear behaviour of the medium on propogation vs. different freqencies[causing resonances], when it becomes non-pistonic, and the result is frequency response anomolies[resonances]. But even these, due to the small scale of physical delay through the solid medium, can be corrected with corrective filters[for example a notch filter that is the inverse of a modal peak applied to the input signal of the transducer. The limitation of the amount of correction that can be performed is one of practical application: every filter adds cost/bulk to a physical crossover circuit, or alternatively requires additional processing power[in a DSP based system]].

-Chris

Perhaps I need to amplify my comments? My original post was in regard to your post about the excursion of a voice coil and Newton's Third law.

I won't be too tongue in cheek, nor I hope put my foot in my mouth on this response.

I was not referring to propagation delay in my post as propagation delay is simply the delay of a signal as it travels through a gate. You might see propagation delay measured in milliseconds if you designed a complex tube based series of gates but normally I would not expect propagation delays to be measured in anything more than microseconds.

I don't understand the part about the decrease as the medium changes? Perhaps that is some sort of hydraulic effect?

I think mass may have something to do with delay as it takes a force to have an object at rest begin its motion (Newtons First Law). I agree that in many instances it is not something that can be perceived but it does have an effect.

There is a lot of stuff in the above post that I won't dwell on but perhaps those wiser than I can. I confess my education is dated and I haven't done much work in semi-conductor and integrated circuit design in a long time. I know it is near sacrilege today but in my ee days we actually studied analog circuitry, however I am familair with some of the terms you discussed both from circuit design and my hobbyist construction of amplifiers and loudspeakers

Mike

 

[WmAx]

I was not referring to propagation delay in my post as propagation delay is simply the delay of a signal as it travels through a gate. You might see propagation delay measured in milliseconds if you designed a complex tube based series of gates but normally I would not expect propagation delays to be measured in anything more than microseconds.

I don't understand the part about the decrease as the medium changes? Perhaps that is some sort of hydraulic effect?

Propogation delay is a broad term, and can be applied to any number of things. My context/mention of the term was in relation to the differences of wave propogation in physical mediums: a higher density/stiffer material of a given mass will have less propogation delay. The issue in relation to speakers is not one shown to be of any significance[except in some marketing literatures. ], and that's why I was wondering if that is what you were talking about. It's now clear that's not what you were talking about at this point.

I think mass may have something to do with delay as it takes a force to have an object at rest begin its motion (Newtons First Law). I agree that in many instances it is not something that can be perceived but it does have an effect.

And the applicable laws in this case[since we are dealing with motion dynamics as well] is the 1st and 2nd law[F=ma]. There is no inherant delay associated with mass; only the amount of force required to produce the same motion. The net effect is that more energy is required to produce the same rate of amplitude/accleration for a higher mass. To put an extreme example out there: Which is going to go from 0-60 the quickest? A Corvette with over 300HP [around 3500 lbs.] or a man on a human-powered bicycle[180 lbs. total]?

-Chris

 

[MBauer]

More Newtonian physics

Propogation delay is a broad term, and can be applied to any number of things. My context/mention of the term was in relation to the differences of wave propogation in physical mediums: a higher density/stiffer material of a given mass will have less propogation delay. The issue in relation to speakers is not one shown to be of any significance[except in some marketing literatures. ], and that's why I was wondering if that is what you were talking about. It's now clear that's not what you were talking about at this point.



And the applicable laws in this case[since we are dealing with motion dynamics as well] is the 1st and 2nd law[F=ma]. There is no inherant delay associated with mass; only the amount of force required to produce the same motion. The net effect is that more energy is required to produce the same rate of amplitude/accleration for a higher mass. To put an extreme example out there: Which is going to go from 0-60 the quickest? A Corvette with over 300HP [around 3500 lbs.] or a man on a human-powered bicycle[180 lbs. total]?

-Chris

It's possible we may be in broad agreement however if I look at your last stateement (and putting all other variables aside, and looking only at power to weight ratio) reduce the mass of the corvette it can accelerate and decelerate faster. I know I added another outside force, brake friction.

I have to respectfully disagree on propagation delay. It is a very specific term in engineering and there may be other terms to describe similiar phenomena in other scientific disciplines but they are not propagation delay. I am hoping that since this is a Forum that often revolves around the performance of electronic and electro-mechanical objects we can use the definition of propagation delay as it would be used in those fields devoted to the study and use of the effected disciplines. Again, as you observed not necessaily found in marketing literature.

As to Newton's first and second law, yes I pointed that out in an earlier post
Mike

 

[WmAx]

It's possible we may be in broad agreement however if I look at your last stateement (and putting all other variables aside, and looking only at power to weight ratio) reduce the mass of the corvette it can accelerate and decelerate faster. I know I added another outside force, brake friction.

Right. But add more force to the same mass, at an inverse proportion to match the theoretical mass reduction that you suggest, and the same result will occur, at the expense of higher force[more energy].

I have to respectfully disagree on propagation delay. It is a very specific term in engineering and there may be other terms to describe similiar phenomena in other scientific disciplines but they are not propagation delay. I am hoping that since this is a Forum that often revolves around the performance of electronic and electro-mechanical objects we can use the definition of propagation delay as it would be used in those fields devoted to the study and use of the effected disciplines.

I'll agree that my use of propogation delay is not a standard use, and I apologize for that. I should have been more clear. I mean, specifically, delay as a result of mechanical wave propagation characteristics of a medium.

http://octavia.ce.washington.edu/DrLayer/theory/T-Basic-Concepts.html

-Chris

 

[pikers]

...Heck, one person told me his latest high-end CD player (with, ugh, a tube output stage) made the balance between orchestra and soloist "better" than his previous one, which put the orchestra "way in the background". Amazing---a CDP that can alter the mix![/QUOTE]

People like you take all of the fun out of this hobby, yet you post in places like this? My advice is let people spend THEIR money how they want, and continue to read graphs and white papers instead of enjoying the gear, since that's apparently what makes you happy.

 

[The Dukester]

Let's get back to the vinyl deal...I still like vinyl over CDs. CDs are obviously convenient and have an incredibly low noise floor, but there is still something about that vinyl. I have several recordings on CD and LP and to me, the album sounds best for most of them, aside from the occasional pop or click.

As far as the more power sounding better, well, maybe not, but who doesn't want MO POWER!? It's like cars...you really don't need it, but who can't resist more? For bragging rights if nothing else!