AVS Forum banner

check all which are true

  • reducing moving mass all else being equal always improves performance

    Votes: 0 0.0%
  • low moving mass is good for midranges and tweeters while subwoofers benefit from higher moving mass

    Votes: 0 0.0%
  • increasing BL all things being equal always improves performance

    Votes: 0 0.0%
  • BL has to be tuned to the application. more is not always better

    Votes: 0 0.0%
1 - 20 of 56 Posts

·
Registered
Joined
·
2,245 Posts
I have an issue with your questions. "better" or "improves" is dependent on the designers goals.

I might assume you mean that for a given volume enclosure, f3 is lower.

If I were manufacturing, I might consider "better" as light enough to ship via UPS.

Your last question alludes to what I am saying: It depends on the designers goals.
 

·
Registered
Joined
·
2,136 Posts
Discussion Starter · #9 ·

Quote:
Originally Posted by LTD02 /forum/post/17012295


1. is false

2. may be true

3. is false

4. is true

i guess if you were tuning a sports car you would screw out all of the spark plugs except in one cylinder and then load the car with 5,000 pounds of lead.


that will make it perform !


it doesn't matter if you're going in a straight or around the corner - you still want less weight and more power. a car needs the same thing to win as the subwoofer needs to be loud - it needs to move fast. and this in turn means power to weight ratio.


DSP in this analogy would correspond the an intelligent all wheel drive system like the one found in nisssan GT-R


extra weight can only increase output at a single frequency at the expense of decreasing it at all other frequencies. lower BL accomplishes exactly the same ! ! ! in other words if your car brakes with the engine and you want to make sure you go fast when you you mash the brake pedal - then this is the only scenario in which your strategy will succeed.
 

·
Registered
Joined
·
2,245 Posts
"Mr. Smith walked down the hall. He knew how it would come. A single bullet to the head."


Or as best I can remember. It was probably 40 years ago since I last read it. Certainly it was before 1984.


"it needs to move fast." It only needs to move as fast as required by the input signal. The louder the faster as it must travel more distance for a given frequency cycle. "Fast" generically would be inaccurate. I don't need a car as "fast" as the GTR ( or that shuts down if I am not at a track) as I try to stay away from 3-digit speeds on the street. Summit Point is another matter. Same with a sub. It only needs to be fast enough for the level and frequency I ask of it. I want only enough mass to be rigid enough for low nonlinear distortion but not so heavy as to bring the ringing into the range where it may be excited. So the answer is a definitive, exactly "it depends"
 

·
Registered
Joined
·
2,136 Posts
Discussion Starter · #11 ·

Quote:
Originally Posted by tvrgeek /forum/post/17014990


"Mr. Smith walked down the hall. He knew how it would come. A single bullet to the head."


Or as best I can remember. It was probably 40 years ago since I last read it. Certainly it was before 1984.


"it needs to move fast." It only needs to move as fast as required by the input signal. The louder the faster as it must travel more distance for a given frequency cycle. "Fast" generically would be inaccurate. I don't need a car as "fast" as the GTR ( or that shuts down if I am not at a track) as I try to stay away from 3-digit speeds on the street. Summit Point is another matter. Same with a sub. It only needs to be fast enough for the level and frequency I ask of it. I want only enough mass to be rigid enough for low nonlinear distortion but not so heavy as to bring the ringing into the range where it may be excited. So the answer is a definitive, exactly "it depends"

at any given frequency faster = louder ...
 

·
Registered
Joined
·
21,345 Posts

Quote:
Originally Posted by vasyachkin /forum/post/17014440


i guess if you were tuning a sports car you would screw out all of the spark plugs except in one cylinder and then load the car with 5,000 pounds of lead.


that will make it perform !


it doesn't matter if you're going in a straight or around the corner - you still want less weight and more power. a car needs the same thing to win as the subwoofer needs to be loud - it needs to move fast. and this in turn means power to weight ratio.


DSP in this analogy would correspond the an intelligent all wheel drive system like the one found in nisssan GT-R


extra weight can only increase output at a single frequency at the expense of decreasing it at all other frequencies. lower BL accomplishes exactly the same ! ! ! in other words if your car brakes with the engine and you want to make sure you go fast when you you mash the brake pedal - then this is the only scenario in which your strategy will succeed.

nah, you used the term "always", as such you must argue against *any* other requirement no matter how ridiculous. if the system is current limited at a particular frequency and adding mass pushes the impedance peak to that frequency, the system may become unconstrained and perform better.


you just need to be more careful with words.


to retort your example, if performance in a car is defined as "smoothness of ride", then adding weight can actually optimize "performance". that's what i call a doozy. ;-)





[for those who didn't get the quip: http://en.wikipedia.org/wiki/Duesenberg]
 

·
Registered
Joined
·
21,345 Posts

Quote:
Originally Posted by Scott Simonian /forum/post/17015524


All those poll questions appear to be answerable either as "true" or "false" depending on application.
So I just skipped them all and labeled it as 'irrelevant'.

#4 is always true.


i guess that you threw in the towell before getting all the way through. can't blaim you. ;-)
 

·
Registered
Joined
·
21,345 Posts

Quote:
Originally Posted by vasyachkin /forum/post/17015111


at any given frequency faster = louder ...

what if instead of "faster", which implies the first derivative aka speed, we go the the second derivative and define "faster" as acceleration. then, perhaps, "faster" becomes _more accurate_, which may or not be louder.


no?
 

·
Registered
Joined
·
21,345 Posts

Quote:
Originally Posted by Scott Simonian /forum/post/17015581


It says, "...has to..." though I felt that it wasn't. Cheaper drivers that aren't optimised to perfection need love too, ya know.

right you are. it's entirely possible that a driver could "slop" its way into a perfect application. that said, the probability of a point estimate being accurate in a statistical distribution actually drops to zero...but now we are just p!ss!ng in each other's faces...perhaps we should redirect our streams at the op.


isn't your next project, a battery of big sealed subs where tweaks don't matter anyways? if yes, then i am sympathetic to your practical approach and your answer to the question. ;-)
 

·
Registered
Joined
·
2,245 Posts

Quote:
Originally Posted by LTD02 /forum/post/17015563


what if instead of "faster", which implies the first derivative aka speed, we go the the second derivative and define "faster" as acceleration. then, perhaps, "faster" becomes _more accurate_, which may or not be louder.


no?

First derivative I think: Speed, distance per time

acceleration, distance per time squared

jerk, distance per time cubed if I remember Calc 101. Gad that goes a long way back. Actually we solved this graphically in drafting. A lot more fun exam than how clean your corners were.
 

·
Bass Enabler
Joined
·
21,719 Posts

Quote:
Originally Posted by LTD02 /forum/post/17015878


right you are. it's entirely possible that a driver could "slop" its way into a perfect application. that said, the probability of a point estimate being accurate in a statistical distribution actually drops to zero...but now we are just p!ss!ng in each other's faces...perhaps we should redirect our streams at the op.


isn't your next project, a battery of big sealed subs where tweaks don't matter anyways? if yes, then i am sympathetic to your practical approach and your answer to the question. ;-)

Roflz!!!



I am a practical man, so yes to that.
These RLp18's are pretty nice drivers though.
 

·
Registered
Joined
·
2,136 Posts
Discussion Starter · #20 ·

Quote:
Originally Posted by LTD02 /forum/post/17015563


what if instead of "faster", which implies the first derivative aka speed, we go the the second derivative and define "faster" as acceleration. then, perhaps, "faster" becomes _more accurate_, which may or not be louder.


no?

doesn't matter which derivate it is. its still going to be a sinewave proportional to BL/MMS.


more BL/MMS means more acceleration means more speed means more displacement means more SPL.


as a matter of fact sound PRESSURE arises from ACCELERATION of air mass unless we're talking about a small sealed chamber then it arises from DISPLACEMENT and if we're talking about a chamber with a resistive vent then it arises from SPEED


confused enough ?

 
1 - 20 of 56 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top