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What is fast speaker?
- Thread starter SomeNoise
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stereofanboy
Addicted Member
Doesn't the amp come into play in this issue? Slew rate or something like that?
dnewma04
The Healer
IME, which is limited compared to Ken's and others on these forums, there are number of things that can make a woofer sound slow. Two things stand out to me as often leading to the impression of slow bass. 1.) Room integration. In low frequencies, the room is in control and the optimum position for mids/highs is very rarely the optimum position for the low frequency drivers. You can spend days trying to get the mids/highs and imaging type effects nailed down and end up with the listening position right in a bass null or a high pressure mode giving the impression of bloated or slow bass. 2.) Instruments that produce deep bass are often accompanied by higher frequency harmonics or possibly and instrument used in conjunction. For instance, a strike of a kick drum might be done in conjunction with the striking of a hi-hat. A lack of ability at higher frequencies can often affect the perception of low frequencies.
There is also the issue of people not really having a solid reference of what deep bass sounds like. When they encounter it, they find it slow even if it's being perfectly represented. Whenever I read about a subwoofer being musical, I can virtually guarantee it won't produce deep bass. Lower extension down to 30-35 hz is common.
Is this a serious question? I thought it was a joke..
Look, if you have a 60 Hz signal and the woofer produces 60 Hz, it is just as fast as any other driver producing 60 Hz... Remember, 60 Hz., means 60 cycles per second... Now if the woofer only produced 58 Hertz when fed a 60 Hz signal, it would be slow....
I think we're confusing damping or acceleration and deceleration. Or perhaps we're confusing efficiency?
Look, if you have a 60 Hz signal and the woofer produces 60 Hz, it is just as fast as any other driver producing 60 Hz... Remember, 60 Hz., means 60 cycles per second... Now if the woofer only produced 58 Hertz when fed a 60 Hz signal, it would be slow....
I think we're confusing damping or acceleration and deceleration. Or perhaps we're confusing efficiency?
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Yup, that's why I said that a "fast speaker" is a psychoacoustic phenomenon. It really isn't the speaker that we perceive as "slow". Our brains take several things that have nothing to do with speed and mush them together into a concept that we can put into words.
:scratch2:
First off, it's a different tone. It had better sound different.
Second, it was an example. I am not sure it's actually possible that you could send a 60 Hz. signal and only get 58 Hz. To do so, the voice coil would have to slip within the motor structure and decouple. I would guess that it would build heat rapidly.
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ken kantor
Fowl Humor
The internet has been a wonderful force for democratization and the spread of information in the world. But, at the same time, it has become utter hell for expertise in many fields. No matter what you say, somebody will contradict you. If you want to "prove" Obama is from Mars or that guns cause impotence or that relativity is incompatible with thermodynamics, Google is right there for you. There's an "expert" for and against every opinion and every claim.
Meanwhile, real professionals are busy doing real work, and cannot possibly win the constant game of whack-a-mole with misinterpreted science, bogus advertising claims and spurious personal testimonials. I am >not< suggesting that the establishment is always right or that experts agree on everything. I'm not even suggesting that all things have been or can be definitively answered. But, there are many established facts in audio science that are constantly dumped on by certain audio hobbyists and their chosen gurus. One of those established facts is: woofer risetime is not a factor in the "fast/slow" bass debate. There are many such myths in audio.
-k
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clydeselsor
Lunatic Member
An auctioneer? :scratch2:
DonQuixote99
just give me some truth
Rant taken, but do you agree or disagree with what Ray said?
And I hope you don't mean to say that things that have 'psycho' as a prefix are outside of the realm of scientific knowledge, and real scientists can only throw up their hands and ignore them. ALL phenomena can be understood (at least in theory).
Of course, while we're waiting, the masses may have to grope their way forward using heuristic folk wisdom.
ken kantor
Fowl Humor
Rant taken, but do you agree or disagree with what Ray said?
And I hope you don't mean to say that things that have 'psycho' as a prefix are outside of the realm of scientific knowledge, and real scientists can only throw up their hands and ignore them. ALL phenomena can be understood (at least in theory).
Of course, while we're waiting, the masses may have to grope their way forward using heuristic folk wisdom.
Don.
Sorry for the rant!
1- I agree with Ray, in that the sense the words "fast" or "slow" are just labels that people use to try and communicate their perceptions. The actual physical situation is unrelated to the "speed" of anything.
2- I do think that there are some consistent physical characteristics of bass reproduction that tend to make listeners use the terms "fast" and "slow."
3- One of the tricky problems is that the sense of "slow" bass can arise from really accurate, deep bass. However, it can also arise from underdamped woofers. Similarly, "tight" bass can arise from temporal masking, overdamped
woofers, a lack of deep bass, etc. etc.
4- "Psychoacoustics" is certainly a field of rigorous scientific study. Generally, the term refers to a broad variety of subjects ranging from those amenable to single variable, controlled experiments, to more difficult areas of cognition, language and opinion.
- k
BTW- I am no longer a Logical Positivist, so I would suggest only that MOST phenomena can be understood. I'm pretty much convinced that every matter currently under debate or study in the audio world falls into that category.
I said:
Then I said:
Then Ken said:
Call me Karnak.
Can you get a little more techy and straighten me out? Why doesn't imperfect tracking of a transient translate to "slow" in the melon? I can see it intuitively but I've never really delved into it so I'm looking to learn.
Most of the time I associate "slow" bass with room effects and the presence of really low bass that people aren't accustomed to hearing. I just intuitively threw the frequency reponse into the overall effect. What's the word?
That's actually where I got my start. I was doing research for the Army Corps of Engineers in psychoacoustics trying to relate sonic events with human annoyance. Measuring the sound was the easy part. Trying to figure out what happened inside the test subjects noggin is a bear. Trying to relate the 2 using math was a struggle that took up 6 years of my life.
Then I said:
Then Ken said:
Call me Karnak.
Can you get a little more techy and straighten me out? Why doesn't imperfect tracking of a transient translate to "slow" in the melon? I can see it intuitively but I've never really delved into it so I'm looking to learn.
Most of the time I associate "slow" bass with room effects and the presence of really low bass that people aren't accustomed to hearing. I just intuitively threw the frequency reponse into the overall effect. What's the word?
That's actually where I got my start. I was doing research for the Army Corps of Engineers in psychoacoustics trying to relate sonic events with human annoyance. Measuring the sound was the easy part. Trying to figure out what happened inside the test subjects noggin is a bear. Trying to relate the 2 using math was a struggle that took up 6 years of my life.
DonQuixote99
just give me some truth
Thank-you for the elaboration, Ken.
Ray, annoyance would often, it seems to me, be mainly a product of what the hearer thinks a sound means. I recall a time when I was setting up a video conference in a room, over ISDN lines, that involved some audible phone dialing noises, not terribly loud. These ordinairly would not be very annoying in an office context. However, they annoyed the HELL out of the woman who thought she owned the conference room at that moment, and resented my coming in to get things ready for the next event. To her, the sounds meant her two-person event at the other end of the room (and she) was not being respected.
Ray, annoyance would often, it seems to me, be mainly a product of what the hearer thinks a sound means. I recall a time when I was setting up a video conference in a room, over ISDN lines, that involved some audible phone dialing noises, not terribly loud. These ordinairly would not be very annoying in an office context. However, they annoyed the HELL out of the woman who thought she owned the conference room at that moment, and resented my coming in to get things ready for the next event. To her, the sounds meant her two-person event at the other end of the room (and she) was not being respected.
TerryO
Super Member
I'm in the same corner as Ray, Dave, Ken and Barred Owl, (and anyone else that I missed) in that I believe that the notion of Fast vs Slow bass can be attributed to either incorrectly damped woofers or room effects. While I certainly use computer sims on cabinet design, I also use the quick and dirty click test when stuffing a speaker, as it seems to work better than some rule of thumb relating to the proportional weight of the stuffing material to cubic volume of the cabinet.
Room effects, I believe, are better understood generally and there are enough threads relating to Acoustic Treatment of listening rooms that I'll leave it there.
Because I find it hard to climb into someone else's head, I'll venture a guess that an incorrect octave to octave balance may lead some to attribute what they hear as fast or slow bass. A reasonably well done FR measurement should show this for what it is. Many of the Subjectivists that relate stories of fast or slow bass, evidently don't perform measurements and may, therefore, be incorrect in depicting what is actually the cause of what they hear.
I therefore propose a new term, that should help in verbally describing the attributes of correct bass performance.
From now on, I will be looking for "Tidy Bass."
This is the ability of a woofer to clean up after itself when the bass note has been delivered. It is both depictive enough to give a general impression as to what's necessary for good bass performance, yet ambiguous enough to give the Audio Talking Heads and Reviewers some wiggle room to extricate themselves when they're dead wrong.
It's a beautiful thing
Best Regards,
TerryO
Room effects, I believe, are better understood generally and there are enough threads relating to Acoustic Treatment of listening rooms that I'll leave it there.
Because I find it hard to climb into someone else's head, I'll venture a guess that an incorrect octave to octave balance may lead some to attribute what they hear as fast or slow bass. A reasonably well done FR measurement should show this for what it is. Many of the Subjectivists that relate stories of fast or slow bass, evidently don't perform measurements and may, therefore, be incorrect in depicting what is actually the cause of what they hear.
I therefore propose a new term, that should help in verbally describing the attributes of correct bass performance.
From now on, I will be looking for "Tidy Bass."
This is the ability of a woofer to clean up after itself when the bass note has been delivered. It is both depictive enough to give a general impression as to what's necessary for good bass performance, yet ambiguous enough to give the Audio Talking Heads and Reviewers some wiggle room to extricate themselves when they're dead wrong.
It's a beautiful thing
Best Regards,
TerryO
ken kantor
Fowl Humor
OK, more technical. How about we start with some definitions? Let's say one presents a step function to the woofer terminals, and simply measures the position of the cone.
- There's a "risetime". In a linear system, this is completely defined by the frequency response. In a non-linear system, there may also be hysteresis and slew-rate behaviors.
- There's some amount of "under-shoot" or "over-shoot", generally related to the damping.
- There's the possibility of "ringing" and an attendant settling time, if the system is underdamped.
- There, hypothetically, can be other "energy storage" mechanisms which further influence woofer motion after a delay.
Is this a comprehensive list?
-k
- There's a "risetime". In a linear system, this is completely defined by the frequency response. In a non-linear system, there may also be hysteresis and slew-rate behaviors.
- There's some amount of "under-shoot" or "over-shoot", generally related to the damping.
- There's the possibility of "ringing" and an attendant settling time, if the system is underdamped.
- There, hypothetically, can be other "energy storage" mechanisms which further influence woofer motion after a delay.
Is this a comprehensive list?
-k
I said:
Then I said:
Then Ken said:
Call me Karnak.
Can you get a little more techy and straighten me out? Why doesn't imperfect tracking of a transient translate to "slow" in the melon? I can see it intuitively but I've never really delved into it so I'm looking to learn.
Most of the time I associate "slow" bass with room effects and the presence of really low bass that people aren't accustomed to hearing. I just intuitively threw the frequency reponse into the overall effect. What's the word?
That's actually where I got my start. I was doing research for the Army Corps of Engineers in psychoacoustics trying to relate sonic events with human annoyance. Measuring the sound was the easy part. Trying to figure out what happened inside the test subjects noggin is a bear. Trying to relate the 2 using math was a struggle that took up 6 years of my life.
Of components of "rise time", sure. So it looks like our definition is from start position to settling at end position including ringing, etc., yes?
Ok, next step?
Sorry, can't agree with that, and this is my take on a "fast woofer."
To show a point, lets take it to the extreme. Let's say the woofer is reproducing a 1/2 Hz sine wave. The cone makes a nice smooth transition from the peak to the trough at a nice lazy rate of 1 cycle per second then back to the peak the next second, etc.
But change the sine wave to a square wave. The speaker still moves in and out at 1/2 cycle per second. But it is no longer a nice lazy arc. The speaker has to instantaneously pop in and out over the course of milliseconds though it waits almost a second before its next movement. A speaker than can easily follow the sine wave may not be able to keep up with the square wave.
budgetaudio6
Addicted Member
toddalin, thats one of the better descriptions of clipping ive read. In how it relates to speakers.
