Pinkmouse,
I notice that you didn't say that the sub with many small drivers sounded bad.
The reason you prefer pro sound drivers to typical high Le high excursion sub drivers is that they don't sound as "slow". I consider it a valid and easy way to avoid the mushy slow sound of typical subs and multiple small drivers is another easy method. You do however run into similar hurdles to overcome in terms of output and extension on the bottom end.
Paul,
I'm sorry but "slow" and "mushy" are much more descriptive and you know exactly what I mean when I use them. In the list of "more appropriate technical" terms, the only one that comes close is transient response but I believe that encompasses much more than just what occurs below 100hz. Of course, you're just looking for something to argue about anyway.
The fact of the matter is that you can take a bunch of cheap little TV drivers and make much better bass than you can with a typical high excursion subwoofer driver and have money to spare.
I notice that you didn't say that the sub with many small drivers sounded bad.
The reason you prefer pro sound drivers to typical high Le high excursion sub drivers is that they don't sound as "slow". I consider it a valid and easy way to avoid the mushy slow sound of typical subs and multiple small drivers is another easy method. You do however run into similar hurdles to overcome in terms of output and extension on the bottom end.
Paul,
I'm sorry but "slow" and "mushy" are much more descriptive and you know exactly what I mean when I use them. In the list of "more appropriate technical" terms, the only one that comes close is transient response but I believe that encompasses much more than just what occurs below 100hz. Of course, you're just looking for something to argue about anyway.
The fact of the matter is that you can take a bunch of cheap little TV drivers and make much better bass than you can with a typical high excursion subwoofer driver and have money to spare.
I made the dig on the pr not so much because theres anything wrong with them, but because in this cases its whats making alot of the real LF response, and well, its 10 inches and not tiny. This is internally inconsistent with thier marketing line of BS. And in one interpretation of "speed" a pr has more group delay than would an active sealed woofer.
And the magazine quote claims "great results from 1-100Hz". Seeing as how a PR enclosure is at least 4th order, dare we imagine a corner frequency somewhere around 2 Hz or less? *snort*
I can just see a quartet of 5" drivers struggling valiantly to push the 15 Hz component of the "Apollo 13" liftoff - even with a PR in the box the viewer'd probably be using voice coil for dental floss after booster ignition.
In a more serious vein, "slow bass" to me seems correlated with flat response followed by a sharp rolloff, which with room gain tends to leave a peak right around the corner frequency (draw the graphs and see), which I suspect is why Linkwitz has a switchable 1st order 50 Hz highpass in the Orion crossover. Vented boxes can mitigate that by using alignments which roll off earlier and less steeply, such as Bessel, instead of Butterworth or Chebyshev. Wilson speakers take that approach, and most people describe them as "fast" even though they use 8", 12" or (heaven forfend!) 15 inch woofers.
Francois.
I can just see a quartet of 5" drivers struggling valiantly to push the 15 Hz component of the "Apollo 13" liftoff - even with a PR in the box the viewer'd probably be using voice coil for dental floss after booster ignition.
In a more serious vein, "slow bass" to me seems correlated with flat response followed by a sharp rolloff, which with room gain tends to leave a peak right around the corner frequency (draw the graphs and see), which I suspect is why Linkwitz has a switchable 1st order 50 Hz highpass in the Orion crossover. Vented boxes can mitigate that by using alignments which roll off earlier and less steeply, such as Bessel, instead of Butterworth or Chebyshev. Wilson speakers take that approach, and most people describe them as "fast" even though they use 8", 12" or (heaven forfend!) 15 inch woofers.
Francois.
Tweeker,
I agree the sub that started this thread is probably a piece of crap like most storebought subs. Using the small drivers it is likely to sound better in the 50-100hz range than most of the stuff they pawn off on the public as subs. They took what I consider a valid point about using multiple small drivers and twisted it to suit their marketing strategy. It's very possible that some accountant told them the 4 smaller drivers would be cheaper than one larger driver and the marketing department is using that as a way to differentiate their product from the other stuff out there and charge extra.
I agree the sub that started this thread is probably a piece of crap like most storebought subs. Using the small drivers it is likely to sound better in the 50-100hz range than most of the stuff they pawn off on the public as subs. They took what I consider a valid point about using multiple small drivers and twisted it to suit their marketing strategy. It's very possible that some accountant told them the 4 smaller drivers would be cheaper than one larger driver and the marketing department is using that as a way to differentiate their product from the other stuff out there and charge extra.
Dave Jones said:
That's the kind of response I'd expect from someone who thinks bass using a pr alignment is the cats meow.
Your little blurb WRT what Klipsch claims is just more justification to use lots of small drivers, more surface area, less excursion. While using ported or pr alignments may help reduce IM distortion, they do plenty to mess up the sound in other ways. If you can't hear the difference, that's your problem.
WRT to references to Fast or Slow bass, they are subjective references to what the bass sounds like, not the velocity of the driver cone. You and Paul already proved that the high excursion drivers have to move their cone with greater velocity. Throw on top of that the high Le which makes those types of drivers slower to get going to begin with and what you end up with is "slow" sounding bass.
Can the people referring to high Le slow bass please refer me to some facts not fiction - AES or similar -Im yet to see a real reason to convert to low Le subwoofer drivers.
Cheers
Are you sure you know HIS reason for enjoying the prosound woofer sound? its probably more along the lines of flux shorting rings and lack of <20hz output making people think its faster bass.
Cheers
Are you sure you know HIS reason for enjoying the prosound woofer sound? its probably more along the lines of flux shorting rings and lack of <20hz output making people think its faster bass.
Check out the texts that Dan Wiggins did in Adire's technical papers. Added mass to the cone didn't slow down the impulse time of the driver, but added Le did.
I'm prepared to accept the use of the term "slow bass" as long as we keep it purely subjective. I think part of the problem here is that those who use that term often don't stop there, but venture into theory that seems a bit shakey and lacking any firm foundation. It's one thing to make observations and subjective descriptions, but it's another altogether to match what we hear with a technical reason. Let's be honest, we mostly amateurs here, some of us have designed speakers, most of use have heard a lot of systems, some of us can measure speakers but few of us have the means to really conduct research here, the kind that can back up claims adequately of what really is the technical reason behind the perception of "slow bass." Most of us form theory to try to make sense of what we have heard.
There are statements here that seem plausible, but I don't see enough evidence here to pin down conclusively what fast/slow bass means technically.
* small woofers are faster
I think if you really want to prove that you want to do some serious research, try to eliminate the differences that can skew perception - it may be that they are only "faster" since they have less bass down low, it might be related to rolloff, it might be transient response, it might be distortion/linearity issues, it might relate to the nature of the cone itself or features of the motor design ....
* higher inductance means better transient response and faster bass
I'm familiar with this article on Adire's website, and they make a good point regarding the inductance impact on the timing of the peaks in an impulse response test. What is not clear is how this actually relates to perception. A study would be needed to determine this with a decent sample and blind listening tests. I suppose if anyone wanted, they could in fact try this out, adding inductance to one of two identical woofers, then using eq to get the same frequency response. They could do blind AB listening tests with a group for 1) standard 2) inductance added 3) frequency response compensated with eq.
I have heard a vented tumult subwoofer that I would describe as very fast. It was calibrated along with 4 other subwoofers to be flat inroom. The Tumult despite its XBL2 design has a high inductance, and that along with the vented box would in the opinion of many, lead to slow bass, but it was certainly not that.
Again, I suggest that we don't really understand fully what produces "fast bass" from a technical point of view. Depending on how I set up my subwoofers, which have lower inductance and are currently in sealed boxes, I can get them easily to sound slower, from what I recall.
So what does this fast bass really mean in technical terms?
I don't know ... I'd like to see someone demonstrate it with credible research, but I'm not sure it will happen. If someone could really prove it, it would be interesting to see if it would change the industry. I have a feeling marketing is a stronger force than research, as the former often feeds on misinformation, being perception based.
But I'll take a stab at what might be involved:
* room modes
I think this is a biggie. My room has a massive peak around 35 - 40 Hz depending on placement and then a dip around 80 Hz. When a sub is placed in the room uncalibrated, that mode creates an exaggerated character to the bass, which for a while I liked, especially on movies since a lot of the potent LFE are around there. If you have small monitors rolling off below 50 or 60 Hz then most likely you avoid room gain and modes which is possibly one of the biggest causes of "slow bass."
* group delay
already suggested, but inconclusive. As you get lower down, it gets harder to keep GD low. A rumble filter increases GD below 40 Hz to crazy high levels. If GD really is a big factor, then this points things in favour of sealed subs, which don't rely on a rumble filter as much, but also have much lower GD, so after a rumble filter is used, they don't look too bad.
* transient response
I'm a little undecided on this one ...
* integration
I've heard the suggestion that "fast bass" relates to having higher frequency content coming from the subwoofer. If the sub level is set louder, or there is a gap in between the sub and mains, they will not integrate well, and the deeper bass will be disconnected from the upper bass and lower midrange, which may in fact be the critical region in giving the impression of "fast bass."
* distortion
as you get lower you have more excursion and higher distortion
There are statements here that seem plausible, but I don't see enough evidence here to pin down conclusively what fast/slow bass means technically.
* small woofers are faster
I think if you really want to prove that you want to do some serious research, try to eliminate the differences that can skew perception - it may be that they are only "faster" since they have less bass down low, it might be related to rolloff, it might be transient response, it might be distortion/linearity issues, it might relate to the nature of the cone itself or features of the motor design ....
* higher inductance means better transient response and faster bass
I'm familiar with this article on Adire's website, and they make a good point regarding the inductance impact on the timing of the peaks in an impulse response test. What is not clear is how this actually relates to perception. A study would be needed to determine this with a decent sample and blind listening tests. I suppose if anyone wanted, they could in fact try this out, adding inductance to one of two identical woofers, then using eq to get the same frequency response. They could do blind AB listening tests with a group for 1) standard 2) inductance added 3) frequency response compensated with eq.
I have heard a vented tumult subwoofer that I would describe as very fast. It was calibrated along with 4 other subwoofers to be flat inroom. The Tumult despite its XBL2 design has a high inductance, and that along with the vented box would in the opinion of many, lead to slow bass, but it was certainly not that.
Again, I suggest that we don't really understand fully what produces "fast bass" from a technical point of view. Depending on how I set up my subwoofers, which have lower inductance and are currently in sealed boxes, I can get them easily to sound slower, from what I recall.
So what does this fast bass really mean in technical terms?
I don't know ... I'd like to see someone demonstrate it with credible research, but I'm not sure it will happen. If someone could really prove it, it would be interesting to see if it would change the industry. I have a feeling marketing is a stronger force than research, as the former often feeds on misinformation, being perception based.
But I'll take a stab at what might be involved:
* room modes
I think this is a biggie. My room has a massive peak around 35 - 40 Hz depending on placement and then a dip around 80 Hz. When a sub is placed in the room uncalibrated, that mode creates an exaggerated character to the bass, which for a while I liked, especially on movies since a lot of the potent LFE are around there. If you have small monitors rolling off below 50 or 60 Hz then most likely you avoid room gain and modes which is possibly one of the biggest causes of "slow bass."
* group delay
already suggested, but inconclusive. As you get lower down, it gets harder to keep GD low. A rumble filter increases GD below 40 Hz to crazy high levels. If GD really is a big factor, then this points things in favour of sealed subs, which don't rely on a rumble filter as much, but also have much lower GD, so after a rumble filter is used, they don't look too bad.
* transient response
I'm a little undecided on this one ...
* integration
I've heard the suggestion that "fast bass" relates to having higher frequency content coming from the subwoofer. If the sub level is set louder, or there is a gap in between the sub and mains, they will not integrate well, and the deeper bass will be disconnected from the upper bass and lower midrange, which may in fact be the critical region in giving the impression of "fast bass."
* distortion
as you get lower you have more excursion and higher distortion
Ofcourse i saw those years ago. The issue is,is the discrepancy audible! thats what no one will answer me.
johninCR said:
mike.e said:
I'll give that great all-purpose answer: "depends".
Essentially Le is like an inductor in series with an ideal resistive voice coil, so it behaves as a first-order lowpass filter, with the attendant effects on frequency and phase response. The second is what slows down the "impulse time" of the woofer, as first-order LPF phase response is still noticeable at points where the frequency response is essentially flat.
In other words, just treat it as another pole in the crossover. Most woofers don't have an Le large enough to affect response at subwoof crossover points, so my attitude is Hakuna Matata.
Francois.
Ok, let see, you want to go with alot of drivers to beat a bigger one, based on Le, and you said we can save money.
For example, how would you beat a 160$ USD Ascendant Audio Atlas 15 with a Le of 0.86 mH ?
Vd = 2.91 liters
I'll try with a DAYTON SD215-8-8 8" SHIELDED DVC SUBWOOFER...
First inductance is higher at 1.2 mH, slower transient response.
Vd = 0.23 liters
With our 160$ budget, we will buy 8 drivers, so 170.80$ USD, going over slightly.
Vd total = 1.86 liters
OK, the Atlas have 40% less inductance and 56% more linear displacement. It will need less displacement to achieve the same SPL, so less THD than 8 drivers, but it already had less THD because the inductance was lower. It's also cheaper.
I guess you will need to give more information to convince me.
For example, how would you beat a 160$ USD Ascendant Audio Atlas 15 with a Le of 0.86 mH ?
Vd = 2.91 liters
I'll try with a DAYTON SD215-8-8 8" SHIELDED DVC SUBWOOFER...
First inductance is higher at 1.2 mH, slower transient response.
Vd = 0.23 liters
With our 160$ budget, we will buy 8 drivers, so 170.80$ USD, going over slightly.
Vd total = 1.86 liters
OK, the Atlas have 40% less inductance and 56% more linear displacement. It will need less displacement to achieve the same SPL, so less THD than 8 drivers, but it already had less THD because the inductance was lower. It's also cheaper.
I guess you will need to give more information to convince me.
Simon,
I'd throw the Dayton in the class of typical subs regardless of size that I wouldn't let near my music. The Atlas on the other hand is the latest thing out there and I wouldn't classify it in the typical category, but 100 of the 50 cent NSB's might do the trick and 200 surely would. The biggest hurdle with little drivers is that to function as a sub you need multitudes of them because you are loading them below Fs and you have to start a low pass filter at the lowest frequency you want to play to get them flat up to Fs, but it can be done.
I'd throw the Dayton in the class of typical subs regardless of size that I wouldn't let near my music. The Atlas on the other hand is the latest thing out there and I wouldn't classify it in the typical category, but 100 of the 50 cent NSB's might do the trick and 200 surely would. The biggest hurdle with little drivers is that to function as a sub you need multitudes of them because you are loading them below Fs and you have to start a low pass filter at the lowest frequency you want to play to get them flat up to Fs, but it can be done.
Well, I just calculated that it would in fact need around 200 NSB to compete against one Atlas 15.
So, it will cost 100$, then I wonder how much it will cost for shipping hehe (around 240 pounds). Another problem is the need for a complete sheet of plywood only for the front baffle.
I'm still not sure it will be cheaper in the end when it's built and all. Also, do you see a driver to replace the NSB when they are depleted? This 49 cent driver is a rare occurence... IMHO.
So, it will cost 100$, then I wonder how much it will cost for shipping hehe (around 240 pounds). Another problem is the need for a complete sheet of plywood only for the front baffle.
I'm still not sure it will be cheaper in the end when it's built and all. Also, do you see a driver to replace the NSB when they are depleted? This 49 cent driver is a rare occurence... IMHO.
Wanna hear what SOUNDS like slow bass? Turn off your mains and lose the opening punch of each bass note. That'll make it seem nice and muddy.
For now this seems to make sense to me.
First of all it's way to early in my experimenting to make solid statements. If I knew for sure what the cause for "slow bass" is, I would have eliminated it already.
Looking at a spectrumanalyser, analysing the music, it's interesting to see that the low frequencies from a bassdrum have a slight delay on the higher bassfrequencies from that same bassdrum.
You can clearly see the kick coming in as a peak around 120-250 Hz and then, about (rough guess) 0,1-0,3 seconds later the lower frequencies with a peak around 60 Hz. It looks more like something that would be easiest corrected with the right crossover frequency and a delay on anything but the sub.
It sure isn't very hifi since your basically changing the signal. But it wouldn't be the first time mankind wants the impossible to be accomplished.
The music that I tested so far that did sound slow also looked slow on the analyser, and vice versa.
Mvg Johan
Rademakers, are you sure you aren't getting confused between the source itself and the reproduction system? Delays of 1 - 3 seconds in the source are one thing, but when you talk about things like transient response and group delay, we are looking at milliseconds!
I have a RTA permanently in my system and I often observe. What I notice is that in movies especially, when you have exaggerated bass, particurly in the midbass region, it can sound boomy, if it's over the top. Most LFE, even when a little exaggerated, as in most action movies are fine. However, occasionally you encounter a burst of bass that is just too much - the room shakes, doors and windows rattle and its this ugly sound.
I have a RTA permanently in my system and I often observe. What I notice is that in movies especially, when you have exaggerated bass, particurly in the midbass region, it can sound boomy, if it's over the top. Most LFE, even when a little exaggerated, as in most action movies are fine. However, occasionally you encounter a burst of bass that is just too much - the room shakes, doors and windows rattle and its this ugly sound.
What is there to be confused about? I wasn't confused (at least I think I wasn't) but now I wander what it could be that could confuse me
I know, I know.
The main question would be: What do you consider slow bass?
I'm just stating perhaps there could be slow bass even when transient response is excellent and groupdelay is around zero.
But perhaps my defenition of slow bass is quite different than yours. So how would you define it then?
Mvg Johan
Interesting discussion.
I don't think one should get bent out of shape about "slow bass". It's a useful concept as long as most people using it know what it means. I would say it's primarily an audiophile term, and audiophiles have a pretty good idea in general of what it means subjectively, even though most would only have a rudimentary idea of why.
There are a couple of obvious things that lead to the perception of slow bass; poor cabinets and/or woofers and room modes. These are things an audiophile would know. As to what makes a poor woofer, audiophiles wouldn't likely know.
The main thing is, slow bass is easy to diagnose. The bass is supposed to drive the music. If the bass seems to lag behind or drag, then it impacts on the musical involvement. The sound is there, but the emotional connection, the intense interest that music can generate, is damaged.
I have a pair of 10" Rocket subs, which have a good reputation for being "musical". But I can destroy their musicality with the wrong crossover point, or with the phase control, or with the onboard single-point eq.
I hear a lot of people saying that fast bass is mainly due to the absence of extreme LF. I think this is probably due to room modes being excited by the lows. But I'll give up extension for musicality any day of the week.
Dan
I don't think one should get bent out of shape about "slow bass". It's a useful concept as long as most people using it know what it means. I would say it's primarily an audiophile term, and audiophiles have a pretty good idea in general of what it means subjectively, even though most would only have a rudimentary idea of why.
There are a couple of obvious things that lead to the perception of slow bass; poor cabinets and/or woofers and room modes. These are things an audiophile would know. As to what makes a poor woofer, audiophiles wouldn't likely know.
The main thing is, slow bass is easy to diagnose. The bass is supposed to drive the music. If the bass seems to lag behind or drag, then it impacts on the musical involvement. The sound is there, but the emotional connection, the intense interest that music can generate, is damaged.
I have a pair of 10" Rocket subs, which have a good reputation for being "musical". But I can destroy their musicality with the wrong crossover point, or with the phase control, or with the onboard single-point eq.
I hear a lot of people saying that fast bass is mainly due to the absence of extreme LF. I think this is probably due to room modes being excited by the lows. But I'll give up extension for musicality any day of the week.
Dan
Johan,
you guys and your blumin' commas! wish we could all just have the same units and symbols!
What you are talking about the source. A delay in the source should not be messed with, if I understand you correctlly in what you are describing.
I have experimented with delay to subwoofers digitally and you have to make quite a change for it to be audible.
Audiophiles .... hmmmm, why is it we all talk about them as if it is some other group? Doesn't audiophile mean "audio loving" ie an audio enthusiast? And if so, aren't we all in fact audiophiles? Seems like we like to use that term to dump on others all the things we think are silly.
you guys and your blumin' commas! wish we could all just have the same units and symbols!
What you are talking about the source. A delay in the source should not be messed with, if I understand you correctlly in what you are describing.
I have experimented with delay to subwoofers digitally and you have to make quite a change for it to be audible.
Audiophiles .... hmmmm, why is it we all talk about them as if it is some other group? Doesn't audiophile mean "audio loving" ie an audio enthusiast? And if so, aren't we all in fact audiophiles? Seems like we like to use that term to dump on others all the things we think are silly.
- Status
- Not open for further replies.