Steve,
Depending upon the spectral content (frequency, amplitude, and time duration) of those resonances they may make the sound perceived as faster OR slower. You have to take many things into account...
For example, many consider the classic BBC monitors as great for fast bass; of course, they have a very high Q design (in the 1.3-1.5 range), while many speakers considered "slower" have Qs below 0.7. Plotting or measuring the total impulse response will show the "fast" speaker as having more ripples for a longer time, but the "slow" speaker will have a longer initial curve (because of the lower frequency it reproduces).
As far as vibration goes, the heavier the moving mass, the lower the resonant frequency for a given compliance. Drivers are a spring-mass system, not a pendulum.
Dan Wiggins
Adire Audio
Depending upon the spectral content (frequency, amplitude, and time duration) of those resonances they may make the sound perceived as faster OR slower. You have to take many things into account...
For example, many consider the classic BBC monitors as great for fast bass; of course, they have a very high Q design (in the 1.3-1.5 range), while many speakers considered "slower" have Qs below 0.7. Plotting or measuring the total impulse response will show the "fast" speaker as having more ripples for a longer time, but the "slow" speaker will have a longer initial curve (because of the lower frequency it reproduces).
As far as vibration goes, the heavier the moving mass, the lower the resonant frequency for a given compliance. Drivers are a spring-mass system, not a pendulum.
Dan Wiggins
Adire Audio
Of course it does. Silly of me. I should have remembered from the time I designed a passive radiator and tuned it with mass.DanWiggins said:As far as vibration goes, the heavier the moving mass, the lower the resonant frequency for a given compliance. Drivers are a spring-mass system, not a pendulum.

What do I know about drivers, Dan?

Interesting, Dan. Thanks.DanWiggins said:For example, many consider the classic BBC monitors as great for fast bass; of course, they have a very high Q design (in the 1.3-1.5 range), while many speakers considered "slower" have Qs below 0.7. Plotting or measuring the total impulse response will show the "fast" speaker as having more ripples for a longer time, but the "slow" speaker will have a longer initial curve (because of the lower frequency it reproduces).
Please clarify. In terms of this subjective impression of speed that we're discussing, are you saying that a high Q design seems faster or that a speaker that doesn't extend as deep seems faster?
It funny how people can get all wraped up in "something" (in this case physics and common driver measurements), and just miss the obvious..
[Most] of what is subjectivly referred to as "speed" is simply a function of driver's excursion.
Common comments:
1. a group of smaller drivers sound "fast".
2. large diameter drivers sound "fast".
3. electrostats sound "fast".
4. bandwidth limited drivers sound "fast".
5. dipoles sound "fast".
6. horns sound "fast".
For #1 your increasing surface area which is virutually the same as #2 (but with a few extras) which limits excursion. For #3 the driver is excursion limited physically. For #4 the limited bandwidth itself, (depending on the driver's paramaters), physically limits excursion. (Of course #4 also coincides with crossover's and #2.) #5 is a bit trickier, at first it appears to be inopposite to the rule I've postulated BUT it isn't. In actuality your average dipole design combines the elements in #1 & #4***. For #6 your obviously limiting excursion via horn loading (provided again that the drivers param.s are suited to this and the horn configuration is correct - and even if this is FURBAR'ed it might be limited simply because the driver itself is physically limited in excursion) - and all this despite hearing audible time-delay.
This of course doesn't mean that there aren't other factors that go into the subjective sense of speed - but the primary factor is in fact driver excursion.
***LOL.. those who skoff at lay-like newbs who ask the question "at what freq. does this occur?".. I mean, they just don't understand the physics behind this.. Right?.. WRONG! Intuitivly these people have grasped something fundamental that others haven't. For instance dipole bass sounds "fast" in the upper bass region but it often does NOT sound "fast" lower in freq. (though other subjective descriptors might apply at these lower freq.s - like "open" or "transparent"). In fact MOST people have never heard low fundamental "fast" bass outside of the event itself. This means then that "fast" bass as a general descriptor is typically limited to freq.s in excess of 50 Hz (i.e at best 50Hz to 220? Hz). A proper basshorn will give you an idea of what "fast" low fundamental bass can be (though you'll really be annoyed at the time delay).
[Most] of what is subjectivly referred to as "speed" is simply a function of driver's excursion.
Common comments:
1. a group of smaller drivers sound "fast".
2. large diameter drivers sound "fast".
3. electrostats sound "fast".
4. bandwidth limited drivers sound "fast".
5. dipoles sound "fast".
6. horns sound "fast".
For #1 your increasing surface area which is virutually the same as #2 (but with a few extras) which limits excursion. For #3 the driver is excursion limited physically. For #4 the limited bandwidth itself, (depending on the driver's paramaters), physically limits excursion. (Of course #4 also coincides with crossover's and #2.) #5 is a bit trickier, at first it appears to be inopposite to the rule I've postulated BUT it isn't. In actuality your average dipole design combines the elements in #1 & #4***. For #6 your obviously limiting excursion via horn loading (provided again that the drivers param.s are suited to this and the horn configuration is correct - and even if this is FURBAR'ed it might be limited simply because the driver itself is physically limited in excursion) - and all this despite hearing audible time-delay.
This of course doesn't mean that there aren't other factors that go into the subjective sense of speed - but the primary factor is in fact driver excursion.
***LOL.. those who skoff at lay-like newbs who ask the question "at what freq. does this occur?".. I mean, they just don't understand the physics behind this.. Right?.. WRONG! Intuitivly these people have grasped something fundamental that others haven't. For instance dipole bass sounds "fast" in the upper bass region but it often does NOT sound "fast" lower in freq. (though other subjective descriptors might apply at these lower freq.s - like "open" or "transparent"). In fact MOST people have never heard low fundamental "fast" bass outside of the event itself. This means then that "fast" bass as a general descriptor is typically limited to freq.s in excess of 50 Hz (i.e at best 50Hz to 220? Hz). A proper basshorn will give you an idea of what "fast" low fundamental bass can be (though you'll really be annoyed at the time delay).
That's very interesting. Presumably this driver excursion theory goes hand-in-hand with frequency response aberrations, or is perceived bass response solely based on excursion? And how about varying delay times, caused by the room, and possibly system infrastructure (acoustic feedback?)?
I believe the perception of 'fast' bass depends largely on two things for most woofers: how well it integrates through its xover range with the next higher frequency driver and how constant its group delay is as the frequency is lowered (which depends also on its loading and any electronic eq).
A high mass woofer or one with a high inductance vc will probably be more difficult to integrate well in its hf xover region, everything else being equal and the resulting phase and amplitude discrepancies in its xover region, as well as any cone breakup and stored energy in the woofer, will in all probability detract from the impression of a 'fast' bass. Also, with the rapidly increasing group delay at lower frequencies that comes with high order br tunings or even relatively high lf rolloffs with closed box systems, the lowest frequencies are progressively delayed in such a way that the lowest frequencies reproduced sound noticeably slower than the rest of the reproduced range of the driver.
One common characteristic of systems with all minimum phase LF poles (or zeroes) is that as you start moving higher in frequency above the highest frequency pole or zero that affects the LF rolloff (but before you get high enough in frequency to approach those that affect the woofers HF rolloff), you always will see group delay declining at 40db/decade regardless of the overall order of the mechanical and electrical transfer functions, since the overall transfer function can be expressed as the product of first and second order polynomials and their respective group delays are additive.
This is all to illustrate that pushing the LF poles as low as possible in frequency, everything else being equal in a relatively flat passband system, will significantly improve the subjective impression of bass 'speed', assuming, of course, that the woofer is also well integrated with the rest of the system through its HF xover range and is operated without producing much distortion.
A high mass woofer or one with a high inductance vc will probably be more difficult to integrate well in its hf xover region, everything else being equal and the resulting phase and amplitude discrepancies in its xover region, as well as any cone breakup and stored energy in the woofer, will in all probability detract from the impression of a 'fast' bass. Also, with the rapidly increasing group delay at lower frequencies that comes with high order br tunings or even relatively high lf rolloffs with closed box systems, the lowest frequencies are progressively delayed in such a way that the lowest frequencies reproduced sound noticeably slower than the rest of the reproduced range of the driver.
One common characteristic of systems with all minimum phase LF poles (or zeroes) is that as you start moving higher in frequency above the highest frequency pole or zero that affects the LF rolloff (but before you get high enough in frequency to approach those that affect the woofers HF rolloff), you always will see group delay declining at 40db/decade regardless of the overall order of the mechanical and electrical transfer functions, since the overall transfer function can be expressed as the product of first and second order polynomials and their respective group delays are additive.
This is all to illustrate that pushing the LF poles as low as possible in frequency, everything else being equal in a relatively flat passband system, will significantly improve the subjective impression of bass 'speed', assuming, of course, that the woofer is also well integrated with the rest of the system through its HF xover range and is operated without producing much distortion.
Crossover integration has little to do with with perceived "fast" response - at least out of the crossovers passband. (though this isn't to say that it can't screw up the freq. balance and detract from a "fast" characterstic.)
The context of the orginal post was with regard to *a* driver - not an integration of multiple drivers. More over, just looking at the subjective qualities of a single driver places this context in rather stark relief with regard to crossover integration. i.e. some drivers have a "fast" sound while others do not, is the crossover really going to ADD to that subjective quality?.. Highly unlikely. Proper integration of a "fast" high freq. driver with a "slow" bass driver is always a matter of "slowing down" the "speed" of the high freq. driver (typically by increasing dampening factor with a resistive device). In fact this is also one of the primary reasons why active crossovers tend to allow drivers to sound "faster" - simply because the driver isn't "slowed down" by components in a passive network. (Note however that the increase in percieved "speed" is usually far less than the difference between what a "fast" driver will sound like in comparison to a "slow" driver.)
Also note that phase has little to do with most sound charactersitics, (disregarding 1 kHz to 4 kHz and HRTF's), except at the cross point (and its bandwidth) where it directly impacts freq. response. Remember that phase rotation in drivers is usually quite substantial over their operating bandwidth and people don't seem to notice it (again excepting the HRTF region). And as for it impacting a "fast" quality - not really. Consider a lowther in a good large backhorn (or scoop). The perceived low freq.s (what little their are) have substantial phase, time delay, and freq. response abberations - and yet you'll be hard pressed to find a loundspeaker with a "faster" sound within that bandwidth. (here is a nice mag. review description of a lowther like quality down to about 50 Hz: http://www.tnt-audio.com/casse/lothpolaris_e.html)
As to SimontY's question:
freq. response abberations are somthing else altogether, but of course if it's driver related then it CAN cause additional excursion. As for perceived bass response - it most certainly is NOT based solely on excursion. Nor is even the subjective quality of "speed" based soley on excursion - BUT in this case it is the primary reason for a "fast" quality. Room characterstics don't seem to alter this charaterstic either (unless you are a substantial distantance from the sound source and the level of the fundamental is substantially lower than the room induced harmonic level).
The context of the orginal post was with regard to *a* driver - not an integration of multiple drivers. More over, just looking at the subjective qualities of a single driver places this context in rather stark relief with regard to crossover integration. i.e. some drivers have a "fast" sound while others do not, is the crossover really going to ADD to that subjective quality?.. Highly unlikely. Proper integration of a "fast" high freq. driver with a "slow" bass driver is always a matter of "slowing down" the "speed" of the high freq. driver (typically by increasing dampening factor with a resistive device). In fact this is also one of the primary reasons why active crossovers tend to allow drivers to sound "faster" - simply because the driver isn't "slowed down" by components in a passive network. (Note however that the increase in percieved "speed" is usually far less than the difference between what a "fast" driver will sound like in comparison to a "slow" driver.)
Also note that phase has little to do with most sound charactersitics, (disregarding 1 kHz to 4 kHz and HRTF's), except at the cross point (and its bandwidth) where it directly impacts freq. response. Remember that phase rotation in drivers is usually quite substantial over their operating bandwidth and people don't seem to notice it (again excepting the HRTF region). And as for it impacting a "fast" quality - not really. Consider a lowther in a good large backhorn (or scoop). The perceived low freq.s (what little their are) have substantial phase, time delay, and freq. response abberations - and yet you'll be hard pressed to find a loundspeaker with a "faster" sound within that bandwidth. (here is a nice mag. review description of a lowther like quality down to about 50 Hz: http://www.tnt-audio.com/casse/lothpolaris_e.html)
As to SimontY's question:
freq. response abberations are somthing else altogether, but of course if it's driver related then it CAN cause additional excursion. As for perceived bass response - it most certainly is NOT based solely on excursion. Nor is even the subjective quality of "speed" based soley on excursion - BUT in this case it is the primary reason for a "fast" quality. Room characterstics don't seem to alter this charaterstic either (unless you are a substantial distantance from the sound source and the level of the fundamental is substantially lower than the room induced harmonic level).
Hi, Scottg -
If a bass driver is in its breakup mode and/or suffering from audible resonant peaks within its pass band, then it is unlikely to sound 'fast' when integrated into a system. Not impossible to accomplish, just unlikely. The same thing holds true for a higher order bandpass SW systems with considerable phase shifts at their hf corner frequencies which are notoriously hard to integrate in high quality systems.
As others have pointed out and contrary to your assertions, the subjective 'speed' of bass drivers (as in the thread title, bass covering that region below, say 300 hz) cannot be effectively evaluated on its own apart from the higher frequencies from other drivers and xover components that it needs to be integrated with.
I believe a 'fast' sound is a result of good group delay characteristics of the entire system, such as a design of mine that will produce well shaped square waves through its xover region, indicating that transient energy is being reproduced with constant overall group delay and amplitude response throughout this region and without significant ringing. The result is a fast, detailed, nearly seamlessly integrated sound between a 15" dynamic woofer and a compression driver driving a CD horn. Of course, I also took care to match their lateral dispersions over the xover region which helps maintain a flat power response. Quasi first order filtering (segueing to third order) and well behaved out of band responses for both the LF and HF drivers without resonant problems avoid subjective slowness and muddiness through the xover region and maintains something approximating the proper envelope response of the signal being reproduced.
I happen to be one of those people who are more sensitive to phase and group delay errors than those who claim they cannot hear them. I can and do, as I discovered when designing HF and LF phase correction circuits for open reel analog tape electronics that corrected phase errors below 100hz and above 5khz. Their effects on the signal were readily audible to me, purely due to their phase correction characteristics. Large phase shifts from steep initial cutoff xovers smack in the middle of the audible range are not my cup of tea, as you might imagine.
Full range drivers sans xover networks are a somewhat different matter than the above, and the discussion above of course does not deal with them.
If a bass driver is in its breakup mode and/or suffering from audible resonant peaks within its pass band, then it is unlikely to sound 'fast' when integrated into a system. Not impossible to accomplish, just unlikely. The same thing holds true for a higher order bandpass SW systems with considerable phase shifts at their hf corner frequencies which are notoriously hard to integrate in high quality systems.
As others have pointed out and contrary to your assertions, the subjective 'speed' of bass drivers (as in the thread title, bass covering that region below, say 300 hz) cannot be effectively evaluated on its own apart from the higher frequencies from other drivers and xover components that it needs to be integrated with.
I believe a 'fast' sound is a result of good group delay characteristics of the entire system, such as a design of mine that will produce well shaped square waves through its xover region, indicating that transient energy is being reproduced with constant overall group delay and amplitude response throughout this region and without significant ringing. The result is a fast, detailed, nearly seamlessly integrated sound between a 15" dynamic woofer and a compression driver driving a CD horn. Of course, I also took care to match their lateral dispersions over the xover region which helps maintain a flat power response. Quasi first order filtering (segueing to third order) and well behaved out of band responses for both the LF and HF drivers without resonant problems avoid subjective slowness and muddiness through the xover region and maintains something approximating the proper envelope response of the signal being reproduced.
I happen to be one of those people who are more sensitive to phase and group delay errors than those who claim they cannot hear them. I can and do, as I discovered when designing HF and LF phase correction circuits for open reel analog tape electronics that corrected phase errors below 100hz and above 5khz. Their effects on the signal were readily audible to me, purely due to their phase correction characteristics. Large phase shifts from steep initial cutoff xovers smack in the middle of the audible range are not my cup of tea, as you might imagine.
Full range drivers sans xover networks are a somewhat different matter than the above, and the discussion above of course does not deal with them.
fast bass?
After wading through this thread and finding myself sometimes agreeing, and sometimes laughing in disbelief, I decided it's time to post a few pics to help illustrate what I think on the subject.
Picture 1 shows a simulated response of the 14cm (5.5") Vifa BC14SG49 mid-woofer in a box that was automatically chosen by Subsim as being an optimal size for the flattest amplitude response. Note that the plot of the group delay indicates that there will be substantial drum-like ringing at around 45Hz, because there the delay is a lot longer than for adjacent frequencies....
After wading through this thread and finding myself sometimes agreeing, and sometimes laughing in disbelief, I decided it's time to post a few pics to help illustrate what I think on the subject.
Picture 1 shows a simulated response of the 14cm (5.5") Vifa BC14SG49 mid-woofer in a box that was automatically chosen by Subsim as being an optimal size for the flattest amplitude response. Note that the plot of the group delay indicates that there will be substantial drum-like ringing at around 45Hz, because there the delay is a lot longer than for adjacent frequencies....
Attachments
Picture 2 shows the same speaker tuned to a lower frequency, and with a lowered box Ql to simulate the addition of extra damping material. Note that the group delay is actually worse, however the ringing will occur at such a low frequency and a reduced amplitude that it's unlikely to be audible. It may sound a lot "tighter"....
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Picture 3 shows what I believe to be the crux of the discussion. The box is undersized, the port is too short, and yet... the group delay is almost flat and very well controlled to practically eliminate any ringing. That sort of group delay is usually associated with Bessel filters, and they produce no ringing when applied to transient waveforms. On the other hand, the amplitude response has a mid-bass peak and quieter low-bass, which may either be seen as a bad design, or seen as a useful transition to a subwoofer + passive baffle-step compensation.
Lech
Lech
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Hi Ya thoriated!
you wrote this:
"..the subjective 'speed' of bass drivers (as in the thread title, bass covering that region below, say 300 hz) cannot be effectively evaluated on its own apart from the higher frequencies from other drivers and xover components that it needs to be integrated with."
My response to this would be that your puting the proverbial cart before the horse. Unless I'm mistaken, Ashok essentially was looking at driver paramaters to select drivers with a certain subjective characteristic. Are you saying he (or anyone else) can not possibly select a driver for a certain characterstic, within the bandwidth they are considering, without integrating it with other drivers via a crossover?
In otherwords what I'm trying to state is that driver selection and eventual integration begins first with selecting a driver for the required bandwidth - not a complement of drivers and crossover components.
you wrote this:
"..the subjective 'speed' of bass drivers (as in the thread title, bass covering that region below, say 300 hz) cannot be effectively evaluated on its own apart from the higher frequencies from other drivers and xover components that it needs to be integrated with."
My response to this would be that your puting the proverbial cart before the horse. Unless I'm mistaken, Ashok essentially was looking at driver paramaters to select drivers with a certain subjective characteristic. Are you saying he (or anyone else) can not possibly select a driver for a certain characterstic, within the bandwidth they are considering, without integrating it with other drivers via a crossover?
In otherwords what I'm trying to state is that driver selection and eventual integration begins first with selecting a driver for the required bandwidth - not a complement of drivers and crossover components.
Adire has a tech paper that indicates that low Le equates to better woofer "speed". Because Le, voice coil inductance, is the driver's magnetic resistance to change in direction. Check out http://www.adireaudio.com/tech_papers/woofer_speed.htm
Although I don't understand all of the math, but I believe the conclusion because:
1. It's a conclusion that's not that favorable to Adire because their woofers have a relatively high Le, especially compared to pro sound woofers like JBL and Eminence.
2. Personal experience - I have a Tempest and JBL 1500gti. The Tempest has a much higher Le than the JBL, but the JBL has a much heavier and stronger cone. The JBL has a much better transient response and sounds much "faster".
As long as the magnet is strong enough, mass of the cone doesn't matter.
Enclosure type is another factor. Vented enclosures, while they can "hit hard" have a delay inherent in the design. Sure they can sound good, but the bass from them doesn't real because delays in the port output cause the sound to mush together. If you really want "fast", what I call dynamic, bass that really sounds like the bass instrument played, then dipole is the way to go.
Although I don't understand all of the math, but I believe the conclusion because:
1. It's a conclusion that's not that favorable to Adire because their woofers have a relatively high Le, especially compared to pro sound woofers like JBL and Eminence.
2. Personal experience - I have a Tempest and JBL 1500gti. The Tempest has a much higher Le than the JBL, but the JBL has a much heavier and stronger cone. The JBL has a much better transient response and sounds much "faster".
As long as the magnet is strong enough, mass of the cone doesn't matter.
Enclosure type is another factor. Vented enclosures, while they can "hit hard" have a delay inherent in the design. Sure they can sound good, but the bass from them doesn't real because delays in the port output cause the sound to mush together. If you really want "fast", what I call dynamic, bass that really sounds like the bass instrument played, then dipole is the way to go.
Well I never!
It makes sense, I noticed better transient response from PA drivers (along with their ragged frequency response).
I wondered how and why, and it makes sense🙂
Thanks for the link, johninCR.🙂
Now what do we do about it?😕

It makes sense, I noticed better transient response from PA drivers (along with their ragged frequency response).
I wondered how and why, and it makes sense🙂
Thanks for the link, johninCR.🙂
Now what do we do about it?😕
Don't buy a woofer without knowing its Le. For 12's and 15's Le's around 1 or less seems good. Once you get up into the 2's and 3's then they definitely slow down as far as musical bass goes.
That paper is rooted in fundamental speed, NOT in the subjective sense of speed. In othwords (like most advertising, its pure crap for the purpose its espoused for.)
Fundamental speed is directly related to freq. response, not surprisingly the higher the inductance the less extended in freq. response for a given SPL.. just like its graphically shown in the paper. When you typically use an inductor in a passive network what are you trying to achieve?.. A lowpass function to reduce high freq. output.
What they try to explain in their graphical view as a time delay does NOT show a delay - instead it shows DAMPENING of the signal. Note however that because of the dampening the negative pulse (or the second "bump" in the impulse response) appears delayed which MAY create a subjectivly "slower" sound - less likely though because its the positive pluse that essentially defines the subjective sense of speed. Subjectivly I've found that instead what it is doing is "butchering" the signal's harmonics.
In otherwords VC Inductance as a value by itself is nearly worthless for the subjective sense of speed. IF your finding that pro drivers are providing a "faster" sound then there are other reasons that may well coincide with a lower VC Inductance. And by the way, though it isn't a physical paramater of the driver, Impulse response can give a relativly decent graphical view of the subjective sense of speed - the closer the two pulses in time the "faster" the driver.
Fundamental speed is directly related to freq. response, not surprisingly the higher the inductance the less extended in freq. response for a given SPL.. just like its graphically shown in the paper. When you typically use an inductor in a passive network what are you trying to achieve?.. A lowpass function to reduce high freq. output.
What they try to explain in their graphical view as a time delay does NOT show a delay - instead it shows DAMPENING of the signal. Note however that because of the dampening the negative pulse (or the second "bump" in the impulse response) appears delayed which MAY create a subjectivly "slower" sound - less likely though because its the positive pluse that essentially defines the subjective sense of speed. Subjectivly I've found that instead what it is doing is "butchering" the signal's harmonics.
In otherwords VC Inductance as a value by itself is nearly worthless for the subjective sense of speed. IF your finding that pro drivers are providing a "faster" sound then there are other reasons that may well coincide with a lower VC Inductance. And by the way, though it isn't a physical paramater of the driver, Impulse response can give a relativly decent graphical view of the subjective sense of speed - the closer the two pulses in time the "faster" the driver.
ScottG,
I didn't think that paper was advertising for Adire. In fact, I thought it was the opposite because Adire's woofers don't compare so well in the Le department.
I'm no expert but the graphs showed me that added mass didn't affect the transient response, yet I read online quite often about "slow heavy cones".
Also, the Tempest and JBL that I own have comparable specs except for the moving mass and vc inductance. The JBL had twice the moving mass and the Tempest has twice the inductance. The transient response (speed) difference is quite audible. Regardless of enclosure type the Tempest sounds tubby and slow by comparison.
So please tell us what affects transient response, if it's not Le.
I'm here to learn, so if I've picked up some bad info, I'd like to know.
I didn't think that paper was advertising for Adire. In fact, I thought it was the opposite because Adire's woofers don't compare so well in the Le department.
I'm no expert but the graphs showed me that added mass didn't affect the transient response, yet I read online quite often about "slow heavy cones".
Also, the Tempest and JBL that I own have comparable specs except for the moving mass and vc inductance. The JBL had twice the moving mass and the Tempest has twice the inductance. The transient response (speed) difference is quite audible. Regardless of enclosure type the Tempest sounds tubby and slow by comparison.
So please tell us what affects transient response, if it's not Le.
I'm here to learn, so if I've picked up some bad info, I'd like to know.
Just to be crystal clear here, did the tempest and jbl have very similar f3 points?
It's a very interesting observation nevertheless!
I have a Tempest, and I should chime in and say (for what it's worth) that I ran it for ages with only one voice-coil, then one day I decided to run it parallel ie. 4ohms total - the bass tightened up and became stronger, and this was a very considerable improvement - it actually started to keep up with my main speakers... Why is this?
It's a very interesting observation nevertheless!
I have a Tempest, and I should chime in and say (for what it's worth) that I ran it for ages with only one voice-coil, then one day I decided to run it parallel ie. 4ohms total - the bass tightened up and became stronger, and this was a very considerable improvement - it actually started to keep up with my main speakers... Why is this?
It may be that the inductance of the two voice oils cancelled out to a degree. It may be that you increased your effective BL.
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