Well, I think Dan is right. But there are a couple of other ways of being "right." The problem is, "fast bass" is a nebulous term. Dan is right that suppessing true deep bass is what some folks are talking about. Or, maybe they are talking about room treatments to minimize resonant modes. Or, maybe they are talking about heavy bafflestep eq, or, lack of eq. Or, maybe they are talking about low nonlinear distortion in the 50-200 Hz range. Or, maybe they are talking about heavily stuffing/reducing internal cabinet modes which lead to issues 100-1k.
So, I don't know what the heck people mean when they say "fast bass." It's a lousy term that should probably be abandoned.
As far as this whole ribbon thread, well, I'll have a thing or two to say about it on my blog in a couple of days.
Mark K's Speaker Pages
So, I don't know what the heck people mean when they say "fast bass." It's a lousy term that should probably be abandoned.
As far as this whole ribbon thread, well, I'll have a thing or two to say about it on my blog in a couple of days.
Mark K's Speaker Pages
ShinOBIWAN said:
Yup. Got it in one. Linkwitz, as usual the fount of wisdom, includes a selectable 50 Hz first order highpass in his crossovers so people can compensate for the +6dB/octave tendency of room gain below about 50 Hz. In many situations using this properly changes bass from thick-sounding to balanced.
Note that Wilson speakers use a Bessel alignment in their vented systems, which rolls off a bit earlier and slower than the standard Butterworth alignment, at close to 6 dB/octave for an octave around the box tuning, and they've gotten good reviews for fast, accurate bass.
"Slow" bass can also come from room modes (different from gain), because a resonant system will take some time to develop full amplitude. For example, if a room has concrete floor and a concrete ceiling eight feet high, then it will tend to develop a floor-to-ceiling resonance around 70 Hz [1]. If there is little furniture and no carpet, the Q could be as high as 10, which means the resonance won't level out until after about a quarter-second of steady-state tone. It'll also take that much time to decay away, too, and that overhang is perceived as sluggish bass. Sorting out this kind of problem goes a long way to making bass sound "fast".
[1] Node at the ceiling and another at the floor yields a half-wavelength of 8 feet. Multiplying by 2 gives a full wavelength of 16 feet, which with the speed of sound at 1125 feet/second comes it at 70 Hz.
Cheers,
Francois.
However we got into a bass discussion from "ribbon tests" amazes me. But fast bass also relates with the phase characteristics of a bass driver and it's integration with the next higer driver. This can be identified listening to Taiko Drums comparing recorded versus listening to live performances. Note the continuity of the harmonics from the moment the drum is hit and the first wave of drum skin rebound, the later portions of the sound would be effected by room modes and ported type designs.
DanWiggins said:
I don't know about the math itself (seems right), but there are a few problems here..
1. moving mass includes the air "load".., though note that this may not be significant since most ribbon manufacturers seem to specifically reference mass (as opposed to moving mass). (...and Raven does this.)
2. 1mm of excursion? I don't think so.. more like .1mm.
ScottG said:
Air load is drag instead of mass, this is proportional to velocity. Mass load is proportional to acceleration. So in a ribbon motion, the peaks are where the mass load is dominant, and the slops are where the air load becomes dominant.
"1mm of excursion? I don't think so.. more like .1mm."
It's not clear, to me anyway, how far from the diaphragm the air is moved.
I don't see any reason to assume it's equal to the diaphragm excursion.
"Air load is drag instead of mass"
That's the case when the air is moving along a surface.
Here, the direction is perpendicular, and the air mass hass to be accelerated by the diaphragm.
I suppose the air at the edges of the ribbon can move sideways, but either way the acclerative force is coming from the diaphragm.
It's not clear, to me anyway, how far from the diaphragm the air is moved.
I don't see any reason to assume it's equal to the diaphragm excursion.
"Air load is drag instead of mass"
That's the case when the air is moving along a surface.
Here, the direction is perpendicular, and the air mass hass to be accelerated by the diaphragm.
I suppose the air at the edges of the ribbon can move sideways, but either way the acclerative force is coming from the diaphragm.
noah katz said:
Drags caused by the pressure difference between the front side and the back side of an object plus skin friction. From a speaker driver point of view, the pressure difference is dominant. Air moving along the surface is dominant only when the head-on cross section is very small and the side surfaces are very large. At least that's what the text books show.
Fast bass
Fast bass can be described as: a bass lunging forward when attempting to injest a worm.
Large mouth bass seem to be a little slower than small mouth bass in this regard.
Jeez, don't any of you guys fish?
Fast bass can be described as: a bass lunging forward when attempting to injest a worm.
Large mouth bass seem to be a little slower than small mouth bass in this regard.
Jeez, don't any of you guys fish?
Not everyone lives near the water like us John😉 . I've posted this article before when the ol' "fast bass" issue popped up (as it will again🙄 ). I believe other posters have mentioned it, but it's really related to the cohesion of the entire bass range: http://www.soundstage.com/maxdb/maxdb061999.htm
Cheers,
AJ
Cheers,
AJ
Here is a subjective review of a product containing the LCY driver Zaph tested:
http://www.6moons.com/audioreviews/jas/orior.html
I think there are two subjective responses here that should be noted:
1. is the "speed" of the ribbon (vs. that of the accuton mid-bass)
2. is that the ribbon sounded louder to the reviewer than the mid-bass driver. (I'll assume that the crossover region was pretty flat.. at least in the reference position.)
Now the reviewer doesn't really transition well from one aspect to the other (..more or less he says the ribbon is "lightining-fast" and then imeadiatly starts talking about a perceived increase in spl).
I've previously discussed what I think "speed" is, but I haven't gone into the subective quality #2.
IMO, #2 "clearly" represents distortion. Typically if two drivers are at the same spl, and one driver sounds louder than the other - that louder sounding driver has signifiantly more harmonic distortion.. (and/or the crossover isn't steep enough in the crossover region and the driver that isn't "louder" has a fair bit of distortion at the top of its passband that "bleeds" into the passband of the "louder" driver - thus increasing the "louder" driver's apparent loudness.)
Of course this subjective "look" at harmonic distortion isn't inclusive of all its character. Different spectrums (or orders) add their own "flavor" to the sound, but as I mentioned previously - this is typically well overstated at the levels found in most loudspeakers when reproducing direct sound.
http://www.6moons.com/audioreviews/jas/orior.html
I think there are two subjective responses here that should be noted:
1. is the "speed" of the ribbon (vs. that of the accuton mid-bass)
2. is that the ribbon sounded louder to the reviewer than the mid-bass driver. (I'll assume that the crossover region was pretty flat.. at least in the reference position.)
Now the reviewer doesn't really transition well from one aspect to the other (..more or less he says the ribbon is "lightining-fast" and then imeadiatly starts talking about a perceived increase in spl).
I've previously discussed what I think "speed" is, but I haven't gone into the subective quality #2.
IMO, #2 "clearly" represents distortion. Typically if two drivers are at the same spl, and one driver sounds louder than the other - that louder sounding driver has signifiantly more harmonic distortion.. (and/or the crossover isn't steep enough in the crossover region and the driver that isn't "louder" has a fair bit of distortion at the top of its passband that "bleeds" into the passband of the "louder" driver - thus increasing the "louder" driver's apparent loudness.)
Of course this subjective "look" at harmonic distortion isn't inclusive of all its character. Different spectrums (or orders) add their own "flavor" to the sound, but as I mentioned previously - this is typically well overstated at the levels found in most loudspeakers when reproducing direct sound.
Made that speaker with the planar (YAG20). OK, it has some of the ribbon traits like much detail and body and projection but its timbre sucks. I prefer domes vs YAG 20. Its synthetic. Fountek is another story. Here's the FR of a very good monitor for tonal balance and transparency (2xHM130C0 in each speaker with the planar on their side inwards), but I cant live with the YAG. I will hand the birch cabs with the YAGS to a mate. The midbass cancellation is due to floor - mic path relative distances.
Attachments
for completeness' sake
This is a bit late-had a bit of trouble uploading to my server. My ribbon comments.
http://206.13.113.199/ncdiyaudio/mark/blog.htm
This is a bit late-had a bit of trouble uploading to my server. My ribbon comments.
http://206.13.113.199/ncdiyaudio/mark/blog.htm
I've been running the BG Neo3PDRs in my living room for the past year and a half. Picked them up early on in my initial DIY experimentation when PE was running them at $35 special. I thought they sounded like crap, even after burn in, so, figuring that it couldn't possibly hurt, and I was playing around with all my various toys in OB config (cheap and easy) I stripped the much vaunted rear chambers off them to get dipole sound out of them.
That's the key. Those back caps or whatever BG is calling them sound like crap. I know the thing was damped with a little bit of fluffy material, but it rang like sticking a tweeter in a soup can. The dipole thing is nice, too, and the Neo3s make excellent drop in replacements for box speakers that use 4" mid drivers. Just remember that if you're going to cross them low (1khz or a bit lower), make sure to use a steep slope (a simple cap won't adequately protect the Neo3 unless you cross at least 2khz in my estimation).
Good sounding, versatile, durable, cheap little drivers, as long as you pull the back cap.
Kensai
That's the key. Those back caps or whatever BG is calling them sound like crap. I know the thing was damped with a little bit of fluffy material, but it rang like sticking a tweeter in a soup can. The dipole thing is nice, too, and the Neo3s make excellent drop in replacements for box speakers that use 4" mid drivers. Just remember that if you're going to cross them low (1khz or a bit lower), make sure to use a steep slope (a simple cap won't adequately protect the Neo3 unless you cross at least 2khz in my estimation).
Good sounding, versatile, durable, cheap little drivers, as long as you pull the back cap.
Kensai
Does anyone know what the BG's effective xmax is?
If you XO these BG's at 1.5 or 2kHz, how is there output capability compared to a good dome like the SEAS?
I'm wondering how they'd be for HT use.
Thanks
If you XO these BG's at 1.5 or 2kHz, how is there output capability compared to a good dome like the SEAS?
I'm wondering how they'd be for HT use.
Thanks
(sorry for my english)
Hi all,
With my Neo3PDR , ( no baffle + rear absorber chamber cm 8 x11x14 stuffed) a minimum safety cap is 10 microFarad. Not for ultra high SPL but adeguate for audiophile-use , IMO.
cheers,
Hi all,
With my Neo3PDR , ( no baffle + rear absorber chamber cm 8 x11x14 stuffed) a minimum safety cap is 10 microFarad. Not for ultra high SPL but adeguate for audiophile-use , IMO.
cheers,
Re: for completeness' sake
Thanks for the comments Mark. Your support means a lot to me. December 2, looks like you wrote that the day after I posted. Judging by some of the forums, it was only an hour or so before riots ensued. Like you, I've stayed out of the debates also. In fact, this posting right here will be my only one in this thread.
"ten most common misconceptions repeated over and over on the boards" So... We're only going to cover 1% of them? 😀
I pulled the rear chambers off my pair last night also. It was severely overdamped without one. Reponse was still relatively smooth but tilted down and extended to about 600hz. I don't think the stock rear chamber was ringing, as it seemed very solid and non-resonant to me, but I do think it was a bit too small. This could have been an intentional power handling ploy by B&G. I would guess that running these dipole would require some serious considerations about running out of Xmax.
I can visually see through the slots that this tweeter has about +/- .5mm Xmax.
As I mentioned above, I'm out of this thread. If anyone wants to start a new thread about the Neo3, I'll join in there. Mark, I'm curious of your comments about the Neo3 also. I'm considering a custom aperiodic damped rear chamber to better shape the low end response. There's some strange raggedness on the low end that I suspect goes away with a better rear chamber.
ucla88 said:
Thanks for the comments Mark. Your support means a lot to me. December 2, looks like you wrote that the day after I posted. Judging by some of the forums, it was only an hour or so before riots ensued. Like you, I've stayed out of the debates also. In fact, this posting right here will be my only one in this thread.
"ten most common misconceptions repeated over and over on the boards" So... We're only going to cover 1% of them? 😀
Kensai said:
I pulled the rear chambers off my pair last night also. It was severely overdamped without one. Reponse was still relatively smooth but tilted down and extended to about 600hz. I don't think the stock rear chamber was ringing, as it seemed very solid and non-resonant to me, but I do think it was a bit too small. This could have been an intentional power handling ploy by B&G. I would guess that running these dipole would require some serious considerations about running out of Xmax.
noah katz said:
I can visually see through the slots that this tweeter has about +/- .5mm Xmax.
As I mentioned above, I'm out of this thread. If anyone wants to start a new thread about the Neo3, I'll join in there. Mark, I'm curious of your comments about the Neo3 also. I'm considering a custom aperiodic damped rear chamber to better shape the low end response. There's some strange raggedness on the low end that I suspect goes away with a better rear chamber.
Just for the record, the word I typed started with "C" and is so tame I had no idea the board with censor it.
And I would have to agree with Zaph's assessment that the chamber inside the cap was simply too small. Left off, but with the driver mounted into a relatively large bookshelf speaker (Yamaha NS6490, using the flush mount BG face plate), they sound better than my initial dipole use.
The "PDR" technology seems to be effective as these speakers are currently mounted in the botom of a large entertainment center, on their sides (I've got the Neo3s mounted in their proper direction, rotated 90 degrees from the supposed "top" of the cabinets), putting the Neo3s a scant 12"-14" from a carpeted floor. Even so, I'm not having any off axis issues or high end attenuation. In fact, on certain well authored DVDs, I'm often startled by the perception of depth and width of sound stage well beyond the stereo pair being used.
Bring on the BG Neo3PDR thread. I'd love to see some folks who actually know what their doing put them to creative use. I'd also love to pick their brains about proper crossover designs for these things so I might squeeze a bit more SQ out of my current (and WAF constrained) setup.
Kensai
And I would have to agree with Zaph's assessment that the chamber inside the cap was simply too small. Left off, but with the driver mounted into a relatively large bookshelf speaker (Yamaha NS6490, using the flush mount BG face plate), they sound better than my initial dipole use.
The "PDR" technology seems to be effective as these speakers are currently mounted in the botom of a large entertainment center, on their sides (I've got the Neo3s mounted in their proper direction, rotated 90 degrees from the supposed "top" of the cabinets), putting the Neo3s a scant 12"-14" from a carpeted floor. Even so, I'm not having any off axis issues or high end attenuation. In fact, on certain well authored DVDs, I'm often startled by the perception of depth and width of sound stage well beyond the stereo pair being used.
Bring on the BG Neo3PDR thread. I'd love to see some folks who actually know what their doing put them to creative use. I'd also love to pick their brains about proper crossover designs for these things so I might squeeze a bit more SQ out of my current (and WAF constrained) setup.
Kensai
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