The transients (or the beater part) of a kick drum usually consists of frequencies from around 1.5kHz and up. The fundamental (body) of kick drums lies somewhere between 60-120Hz. Below that there is mostly arbitrary, unwanted mush which tends to get eq'd out during the recording/mix stage.
Sometimes a little 'air' (6kHz and up) helps to get a good, well-defined kick drum sound.
All transients tend to be high frequency components of sounds with much lower fundamentals.
Sometimes a little 'air' (6kHz and up) helps to get a good, well-defined kick drum sound.
All transients tend to be high frequency components of sounds with much lower fundamentals.
A resonant system with Q=1 has a faster rise time than one with Q=0,5 at the cost of overshoot and slow decay. You can use the overshoot to counteract the slow ring-in of a membrane and you can ignore the decay, because it will be concealed by the decay the room adds to the equation.
Charles Darwin explained it right. What you need to perceive a bass note as fast happens in the frequency range above that of a subwoofer. The important thing is to get the integration right. Look at what they do in cars. They have big long-stroke subwoofers for the extreme low end and 6 inch drivers that add the kick or what you would call the speed.
Integration - Lowther Acousta
Hi guys,
quote, pacificblue: "...The important thing is to get the integration right...."
And that gets us back to the original question: what would integrate best with a Lowther Acousta, i.e.: a backloaded horn with at least somewhat questionable low frequency behaviour. I still think that a tapped horn should integrate well with the horn output.
Regards,
Hi guys,
quote, pacificblue: "...The important thing is to get the integration right...."
And that gets us back to the original question: what would integrate best with a Lowther Acousta, i.e.: a backloaded horn with at least somewhat questionable low frequency behaviour. I still think that a tapped horn should integrate well with the horn output.
Regards,
Experience here shows if there is not a 6"-8" driver in the system there will never be good drum sounds. It takes all the best drivers have to match the sound of a drum which mean a driver about the size of the moving part of a snare... about half the diameter of the drum head. Think of a "black dot" drum head.
Best impulse (closest to drive signal) response of a loudspeaker transducer occurs with a Q=.577 (Bessel) in a closed box. Rise time is more closely related to the Fb than the Q. Pacificblue has an accurate description except for noting frequency has more to do with rise time. Obviously a tweeter has a shorter rise time than a woofer.
Want to "speed up" the bass? Move the woofer closer to the listening position than the mid and high frequency transducers. The bass will arrive "sooner" and seem faster. Try it and see. Very easy to do!
Best impulse (closest to drive signal) response of a loudspeaker transducer occurs with a Q=.577 (Bessel) in a closed box. Rise time is more closely related to the Fb than the Q. Pacificblue has an accurate description except for noting frequency has more to do with rise time. Obviously a tweeter has a shorter rise time than a woofer.
Want to "speed up" the bass? Move the woofer closer to the listening position than the mid and high frequency transducers. The bass will arrive "sooner" and seem faster. Try it and see. Very easy to do!
To put this in simple terms that most people can understand, in order for a bass system to be perceived as 'fast' assuming the integration is there and the rest of the frequency range is being competently reproduced, the loudspeaker/enclosure/bass loading/room acoustic system needs to be capable of reproducing 'all the sound' - low-frequency wavefronts at full magnitude in proportion to the rest of the signal - without any delay outside the integration time of the ear, instead of taking several cycles to 'rise' to a steady-state output level. That is, if there are multiple cycles where the system is getting louder and louder with each cycle, the length of that time to rise to full output level is perceived as 'speed'.
A kick drum does have plenty of high harmonic content, but it also has high-level content down to just above DC. And rise times that are less than half a cycle aren't meaningful, so studying the rise time of the first quarter of a sinewave at a certain frequency isn't what I'm after. I'm talking about resonant systems (including room excitation) that require several cycles to pick up steam until the combined magnitude of both the active radiator and the resonant means is the same for every subsequent cycle.
Beyond a certain point I realize I'll be talking to people with their heads in the sand, since it seems high-end audio is equal parts superstition, religion, and engineering, which is why I typically prefer to inhabit the professional domain (where superstition and religion only go so far as brand loyalty). That article that MaVo posted wasn't very good once you look past the mumbo-jumbo, but I'm not going to dissect it here (unless someone asks me to or challenges me on some point of the article). That guy seemed to have only a listener's grasp of acoustic engineering, and beyond that it was obvious he was a poseur and out of his league, even to the point of confusing comb filtering (a frequency-domain artifact) with beating (a time-domain artifact). It seemed he ignored the role of enclosures and rooms entirely and focused only on the mass and acceleration of the driver itself. If you do that, then yeah - a 'fast' woofer is a woofer with midrange extension.
That 'moving the sub' thing really does work. I've employed a similar technique to produce 'faster' bass in an install I did in a contemporary (rock music) church sanctuary by using digital delay in the system processor (which most newly-installed professional audio systems employ unless their designer was a bonehead), and subjectively it did improve the speed of the bass. The subs were flown less than 2 feet behind the FOH mains, and the amount of delay applied to the rest of the system was about 7 ms in this particular room (long and narrow).
A kick drum does have plenty of high harmonic content, but it also has high-level content down to just above DC. And rise times that are less than half a cycle aren't meaningful, so studying the rise time of the first quarter of a sinewave at a certain frequency isn't what I'm after. I'm talking about resonant systems (including room excitation) that require several cycles to pick up steam until the combined magnitude of both the active radiator and the resonant means is the same for every subsequent cycle.
Beyond a certain point I realize I'll be talking to people with their heads in the sand, since it seems high-end audio is equal parts superstition, religion, and engineering, which is why I typically prefer to inhabit the professional domain (where superstition and religion only go so far as brand loyalty). That article that MaVo posted wasn't very good once you look past the mumbo-jumbo, but I'm not going to dissect it here (unless someone asks me to or challenges me on some point of the article). That guy seemed to have only a listener's grasp of acoustic engineering, and beyond that it was obvious he was a poseur and out of his league, even to the point of confusing comb filtering (a frequency-domain artifact) with beating (a time-domain artifact). It seemed he ignored the role of enclosures and rooms entirely and focused only on the mass and acceleration of the driver itself. If you do that, then yeah - a 'fast' woofer is a woofer with midrange extension.
That 'moving the sub' thing really does work. I've employed a similar technique to produce 'faster' bass in an install I did in a contemporary (rock music) church sanctuary by using digital delay in the system processor (which most newly-installed professional audio systems employ unless their designer was a bonehead), and subjectively it did improve the speed of the bass. The subs were flown less than 2 feet behind the FOH mains, and the amount of delay applied to the rest of the system was about 7 ms in this particular room (long and narrow).
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Yah that is it also, toast to Tater.
Pro ehy? Me too.Have got a cone treatment for waterproofing & damping made with unequal parts "superstition, religion, and engineering." Works good.
Don't design, service, or install without DSP. Always tell the prospective to go find an amateur instead. No ports allowed either.
It is always worth it to see a person's face the first time in their life they hear real bass. It's FUN!
Gastronomical Distress! I have made myself sick more than once listening to Madonna Erotica with that heavy gut punch bass on that album to loud.
Pro ehy? Me too.Have got a cone treatment for waterproofing & damping made with unequal parts "superstition, religion, and engineering." Works good.
Don't design, service, or install without DSP. Always tell the prospective to go find an amateur instead. No ports allowed either.
It is always worth it to see a person's face the first time in their life they hear real bass. It's FUN!
Gastronomical Distress! I have made myself sick more than once listening to Madonna Erotica with that heavy gut punch bass on that album to loud.
It is not so much a question of which type of subwoofer to choose, but to get the crossover right. That means to
- choose the right crossover frequency
- choose the best filter slopes for the drivers involved
- choose the correct filter Q factor
all to get a flat frequency response.
Then you need to phase and/or time align the drivers, which is what Taterworks and sumaudioguy are talking about. That can best be done with professional equipment. Several Forum members use the Behringer DCX2496 which can do all of the above tasks and is still affordable.
Maybe you can point me to some literature about that. So far I have seen many graphs that show the ring-in for different Q factors like the one below.
I have not yet seen one that shows ring-in for different resonant frequencies.
The short rise time is an effect of the motor force to mass and friction ratio which is much higher in a tweeter than in a woofer. The high resonant frequency is an effect of the interaction between suspension, losses and mass. A high resonant frequency is not the cause of short rise time.
In a large orchestra the bass instruments is actually played before higher instruments to not sound slow.
The rise and fall time of a resonance in a subwoofer is seldom talked about when talking "fast" bass.
It's usually "fast bass is a tweeter" or "there is no such thing as fast bass". Makes me annoyed and I eventually got tired of explaining it.
I think I find slow decay worse than slow rise as midrange takes care of "attack" anyway, a long decay gives sort of a slow muddy residue.
I have not found that much "transient" bass below 40Hz so a well designed resonance based system should be fine, although I would rather use quarter wave based system than half wave (BR).
Besides it's easier to get a good decay that way.
The rise and fall time of a resonance in a subwoofer is seldom talked about when talking "fast" bass.
It's usually "fast bass is a tweeter" or "there is no such thing as fast bass". Makes me annoyed and I eventually got tired of explaining it.
I think I find slow decay worse than slow rise as midrange takes care of "attack" anyway, a long decay gives sort of a slow muddy residue.
I have not found that much "transient" bass below 40Hz so a well designed resonance based system should be fine, although I would rather use quarter wave based system than half wave (BR).
Besides it's easier to get a good decay that way.
<snip>
Maybe you can point me to some literature about that. So far I have seen many graphs that show the ring-in for different Q factors like the one below.
I have not yet seen one that shows ring-in for different resonant frequencies.
The short rise time is an effect of the motor force to mass and friction ratio which is much higher in a tweeter than in a woofer. The high resonant frequency is an effect of the interaction between suspension, losses and mass. A high resonant frequency is not the cause of short rise time.
Really thought the graph posted is the normalized curves with Q and omega (2*pi*F) of an any filter. No matter the frequency the shape of the curve is identical. Only the time scale and resonant frequency change. Even amplitude stays the same. So would say you already have the info you seek.
Because the filter function is always the same it is easy to see rise time is exactly related to Q and Fs of any filter. The motor and all that have to do with the final Q of the mechanical filter so ... Q and Fs becomes Qb and Fb in the box.
Do suppose pacific blue suggest bigger magnets and so on and all that is fine. Did not have any comment worth writing with your other post and sorry for that confusion. Really thought more that you were mired in details. Second order filters are all the same. Only Q and Fs change. Rise time is closely related to Fs and Q and may be determined from those parameters. Mass and motor and magnet may change those values for Fb and Qb but the curves always remain the same.
As for fast bass only DSP here but this gentleman wanted analog and the Merchand part I linked to is still the cheap good/best answer. Also move the subs closer will help apparent speed.
In music the bass player hits just "front of the beat" and the drummer hits on the end of the beat to have the timing sound right in music. Moving the woofer more near moves the bass ahead in time, faster.
All that stuff about crossovers and so on is another major subject and on DIYaudio there seems to be almost no agreement on how to make a crossover. I have my method which works for me and the installs done here. Others have theirs. MUCH disagreement here on DIY!
=SUM
A word from a (justifiably) modest poster: there seems to be some lack of attention to basic Fourier-transform issues. Whatever sound the drum is making, the low tones go to the woofer and the middle to the squawker and the high.... As long as the woofer woofs well, it plays the low notes honky-dory. The midrange and to a surprising great extent, the tweeter does the "impact."
Am I missing something?
BTW, I am entirely in agreement with Taterworks about the poor sound of anti-resonant tuned boxes. But isn't the oddly-named tapped horn just such a tuned box?
Am I missing something?
BTW, I am entirely in agreement with Taterworks about the poor sound of anti-resonant tuned boxes. But isn't the oddly-named tapped horn just such a tuned box?
The best sub is a good midbass.
The tweeter might fill in the last "snap" but a good midbass does most of the work.
I did a quick experiment a while back where I tested out some 15" midbass. I already had a two way hooked up for 80Hz+ and TH for sub.
The midbass was run 80-800Hz with the two way doing 800Hz+
I used the DCX to shift between the two setups and for some reason the 15" midbass made the sub go lower.
Same volume and everything. Just lower with more impact.
"But isn't the oddly-named tapped horn just such a tuned box? "
Indeed. But for some reason I find it fast and "punchy".
I just looked at a recorded IR of my first TH that I am not 100% happy with and compared it with a Q0.577 simulated rolloff at 30Hz bandpassed to similar range. The difference is minimal and shows very little resonant behavior even though it was measured in-room.
The amp was a crappy "thing" that powers a 2.1 computer "sub" connected through signal cable instead of real cable.
Here is the graph, not the best but you get the point.
http://img263.imageshack.us/img263/9861/ircompare.png
The tweeter might fill in the last "snap" but a good midbass does most of the work.
I did a quick experiment a while back where I tested out some 15" midbass. I already had a two way hooked up for 80Hz+ and TH for sub.
The midbass was run 80-800Hz with the two way doing 800Hz+
I used the DCX to shift between the two setups and for some reason the 15" midbass made the sub go lower.
Same volume and everything. Just lower with more impact.
"But isn't the oddly-named tapped horn just such a tuned box? "
Indeed. But for some reason I find it fast and "punchy".
I just looked at a recorded IR of my first TH that I am not 100% happy with and compared it with a Q0.577 simulated rolloff at 30Hz bandpassed to similar range. The difference is minimal and shows very little resonant behavior even though it was measured in-room.
The amp was a crappy "thing" that powers a 2.1 computer "sub" connected through signal cable instead of real cable.
Here is the graph, not the best but you get the point.
http://img263.imageshack.us/img263/9861/ircompare.png
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One more thing about the Merchand piece is it address the apparent increase in output around 80Hz due to second harmonic distortion (from 40Hz) where that piece provides a dip in the response. Have done exactly the same thing with the DSP for a lot more money and it does help the "muddy" sound.
As a note, using DSP and 5 woofer with 5 amps was able to get +/- 2dB for 24-100Hz except for the +3 at 20Hz. Many hundreds of engineers have used this studio system and even the rappers believe it has good bass. Qb=.5, Fb=28Hz. Not that this is a normally "sane" solution. Fun to listen to though.
As a note, using DSP and 5 woofer with 5 amps was able to get +/- 2dB for 24-100Hz except for the +3 at 20Hz. Many hundreds of engineers have used this studio system and even the rappers believe it has good bass. Qb=.5, Fb=28Hz. Not that this is a normally "sane" solution. Fun to listen to though.
I think you are right but for the wrong reasons and you are forgetting Fourier. Let's get guts feel out of this: the impact isn't in the woofer.
Going clean down to say 80 Hz does give great bass and if it cut off there, nobody would know, typically. The struggle to get good bass below leads to grief UNLESS you aim, as you have, for good "mid bass" and then have some further dedicated specialized subwoofer.
Yeah, I had to re-think "tuned" when I wrote my first post because almost all systems have resonances in the operating range and hence have to work with them. Bass reflex "works" with them in a more inherent way than say, a sealed box or dipole and is correspondingly more affected (for the worse) by them.
In order not to be tossed from this forum or at least cautioned, I better not offer my true opinion in basic language on where tapped horns fall in this spectrum.
Footnote: ESLs are fairly free of resonance issues, at least big resonance issues. Curiously, a Klipschorn does have a rather small sealed box behind the driver but the horn helps control the box and vice versa.... ummm, an idea to improve a tapped horn???
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Hi guys,
quote: "bentoronto: ...anti-resonant tuned boxes..."
I must have missed that one, where does Taterworks talk about such a thing, and what is it?
quote: "sumaudioguy: ...the Merchand piece..."
I assume you are talking about Marchand Electronics' WM8 from your Post #8? Nice unit.
David_Web: Can you, please, expand on the test signal, and setup, used for the very interesting impluse response comparison in Post #52, and do you have more data you can share pertaining to the impulse response of tapped horns? To me that is where the meat is in finding a suitable mono-sub for cr0wl3y's Acoustas.
Regards,
quote: "bentoronto: ...anti-resonant tuned boxes..."
I must have missed that one, where does Taterworks talk about such a thing, and what is it?
quote: "sumaudioguy: ...the Merchand piece..."
I assume you are talking about Marchand Electronics' WM8 from your Post #8? Nice unit.
David_Web: Can you, please, expand on the test signal, and setup, used for the very interesting impluse response comparison in Post #52, and do you have more data you can share pertaining to the impulse response of tapped horns? To me that is where the meat is in finding a suitable mono-sub for cr0wl3y's Acoustas.
Regards,
Post #40..."This becomes a problem when a loudspeaker relies heavily on resonant means to reinforce its low-frequency output, because this initial pressure wave contains information almost down to DC, but the loudspeaker's resonant means (port, passive radiator, transmission line, horn, daline, acoustic lever, etc.) may require several cycles to reach its steady-state condition. Every resonant system stores and releases energy over time, and the ratio of this stored energy to the released energy describes the resonant character of that system."
"The way to achieve bass with a short 'rise time' is to first design a low-frequency system that itself has a very short rise time (a critically-damped sealed alignment with Qtc of 0.5 or less would work well but have low sensitivity, so you'll need multiple drivers and plenty of power), and then apply something like the Geddes multi-sub approach together with room EQ to confound the room's own modal behavior and compensate for whatever you can't eliminate with the multi-sub approach by applying the EQ, so that the combined output of the multiple subbass sources is roughly in-phase at the listening position and the average output of the multiple sources is relatively free of modal reinforcement and the summation of the room pressurization is even throughout the room."
It was not a real test per say.
I used HOLMImpulse (sine sweep) to measure the response, going with a cheap mic and laptop. The goal was to remove most HF garbage with the BFD due to crappy lowpass in the amp. It was a quick setup used for a movie and I simply happen to have the last measurement saved.
Yet a resonant behavior should have been clearly seen if present.
The Q0.755 was generated by HOLMImpulse and lowpassed by it's internal filter.
I intend to make some real measurements and compare IR to what hornresp models at some point.
But it already looks to match very well.
I might be wrong but due to the size of the opening in relation to the pipe there is not much there to trap and sustain a resonance. But that definitively depends on how the TH is made.
I think that the biggest mistake is tuning too low with too much bass. Inviting too much resonance.
Read the quotes by Tom Danley here.
Simple Tapped Horn Tutorial using Hornresp - AVS Forum
I used HOLMImpulse (sine sweep) to measure the response, going with a cheap mic and laptop. The goal was to remove most HF garbage with the BFD due to crappy lowpass in the amp. It was a quick setup used for a movie and I simply happen to have the last measurement saved.
Yet a resonant behavior should have been clearly seen if present.
The Q0.755 was generated by HOLMImpulse and lowpassed by it's internal filter.
I intend to make some real measurements and compare IR to what hornresp models at some point.
But it already looks to match very well.
I might be wrong but due to the size of the opening in relation to the pipe there is not much there to trap and sustain a resonance. But that definitively depends on how the TH is made.
I think that the biggest mistake is tuning too low with too much bass. Inviting too much resonance.
Read the quotes by Tom Danley here.
Simple Tapped Horn Tutorial using Hornresp - AVS Forum
Hi guys,
BP1Fanatic: I do get the general drift of the discussion, but I have not heard of "anti-resonant tuned boxes" before, and neither had the google - until now (aperiodic maybe?, but that has its own definition). Thanks for the reference.
David_Web: I think you mean Q=0.577? Thanks for the clarification, and I hope you get to make more measurements that you can share. I have been very interested in the tapped horn's workings, and am sad to say that I have not been in a position to build or measure anything lately. Thus I'm just trying to learn by observing, and asking dumb questions.
I do appreciate all the efforts being put forth. Thank you.
Regards,
BP1Fanatic: I do get the general drift of the discussion, but I have not heard of "anti-resonant tuned boxes" before, and neither had the google - until now (aperiodic maybe?, but that has its own definition). Thanks for the reference.
David_Web: I think you mean Q=0.577? Thanks for the clarification, and I hope you get to make more measurements that you can share. I have been very interested in the tapped horn's workings, and am sad to say that I have not been in a position to build or measure anything lately. Thus I'm just trying to learn by observing, and asking dumb questions.
I do appreciate all the efforts being put forth. Thank you.
Regards,
the deeper you go, the slower it gets
thats the nature of the frequency
but I suppose thats been said before
tho, phase variations can make it seem slower, or faster
integrated well, and you wont notice neither fast nor slow, its just there
whether one design is better than another I would say also depends on design of the main speakers
and the music, listening habbits, electronics, etc
in the early days of subs design, it concerned only whats below 40hz
today I would strech it to maybe whats below 50hz
but today some use a sub even up to 100hz, some even higher
seems todays subs are difficult to be specific about
thats the nature of the frequency
but I suppose thats been said before
tho, phase variations can make it seem slower, or faster
integrated well, and you wont notice neither fast nor slow, its just there
whether one design is better than another I would say also depends on design of the main speakers
and the music, listening habbits, electronics, etc
in the early days of subs design, it concerned only whats below 40hz
today I would strech it to maybe whats below 50hz
but today some use a sub even up to 100hz, some even higher
seems todays subs are difficult to be specific about
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