In college my friends room mate had a very low distortion monitor. Quite high quality in the mid range especially and low measured distortion. My friend had a old pair of inexpensive Altec Lansing 2 ways with 8 inch folded paper surround that were not at that level of sophistication. Guess what, we all agreed that the lower budget Altecs were FAR more engaging in the bass/ mid bass region. The mid/treble was defiantly better in the high priced monitor BUT the Altecs completely trounced them in the bass region. NO not because there was more, they actually didnt go as deep, BUT they were much more alive, more like real bass.
So what am I saying. That it may not be so much the distortion overall as it may be the type of distortion that is a bigger issue and im not sure how well hysteresis distortions are understood or measured.
A relevant quote from Green Mountain Audio:
"Of great importance also is to find out how well a driver behaves at all loudness extremes from very soft to very loud. This is called dynamic linearity or conversely, power compression (at high power).
The louder the test signal becomes, the easier it is to measure what might be going wrong.
On the other hand, there is almost no way to measure how accurately the cone or diaphragm moves on very small strokes, something the small sounds of music requires.
One must discover what prevents motion on tiny signals by studying the principles behind the concept of flexibility, including 'stiction' and 'hysteresis.'
Then, the potential for good low-level behavior can be seen by examining the suspension of a raw woofer and tweeter."
"Of great importance also is to find out how well a driver behaves at all loudness extremes from very soft to very loud. This is called dynamic linearity or conversely, power compression (at high power).
The louder the test signal becomes, the easier it is to measure what might be going wrong.
On the other hand, there is almost no way to measure how accurately the cone or diaphragm moves on very small strokes, something the small sounds of music requires.
One must discover what prevents motion on tiny signals by studying the principles behind the concept of flexibility, including 'stiction' and 'hysteresis.'
Then, the potential for good low-level behavior can be seen by examining the suspension of a raw woofer and tweeter."
YES! and this is probably why tensioned film radiators have such good low level listening. They have very low to no stiction and hysteresis
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I fully agree with that. For bass, bigger drivers do it better, regardless of volume. That's just the laws of physics. Listeners do diverge, though, as to how much importance one attaches to bass vs midrange, and what kind of bass one prefers. I'm mostly a classical/jazz dude. The most important thing for me is to get the midrange right. And I like my bass clean and tight and overdamped, bordering on anemic. Others will like a less damped and "rawer" bass.
So for my musical taste, a two-way monitor with a 6.5 woofer does just fine for the listening I do when I get tired of answering emails (I spend more time listening to music at my office than I tell my boss). If I mostly listened to electronica and modern studio music on the other hand, I would never buy a monitor with anything less than 8" for the bass/midrange.
For my home system, though, I prefer to have my cake and eat it too.
Yea while there are preferences to be sure, I suspect we may be talking about something more universal here with the Hysteresis thing. I suspect you could have two systems with exactly the same FR and overall low freq damping/ roll off, BUT if one used a more linear spring type suspension and the other a more hysteretic suspension that most would prefer the linear spring. In other words the two have the same measured performance BUT one used hysteresis component to achieve it and the other did not.
I would say no or only by a small margin.
If you had an OB bass section with a highly hysteretic cone surround it would still have the problem.In fact with OB it may be an even bigger problem IMO.
And I suspect the stuffing materials are not as much of an issue so long as there isnt too much used.
I have built many OB systems. IMO simply getting rid of the box resonances AND the fact that the room modes are not as much of an issue as IB is the bulk of why OB sounds like it does.
Only just noticed this thread or I would have chimed in earlier.
I use Eminence Alpha 15a in one of MJK's small, passive OBs. I have always been surprised at how good the bass is at low volume. MUCH better than my other builds. And I note the the Alpha 15a has Q(ms)= 7.23 . One more data point in favor of high Q(ms) and OB.
I use Eminence Alpha 15a in one of MJK's small, passive OBs. I have always been surprised at how good the bass is at low volume. MUCH better than my other builds. And I note the the Alpha 15a has Q(ms)= 7.23 . One more data point in favor of high Q(ms) and OB.
Agreed!
Anecdotal evidence only
Did a couple of quick tests. Took out most of the stuffing on my sealed NE265W-08box. Was maybe a small perceived improvement?
Grabbed the 8NDL51 in sealed alignment stuck it behind the above box firing up like Audio Kenisis late ceiling splash. Delayed the main speakers a bit, xover around 250hz BW3, eqed to roughly the same curve as the single box above. Sound seemed much improved in the mid-base department. Clearer and able to listen at what seemed like lower volume comfortably.
To me in my room.....seems like the effects are additive. Low mechanical loss drivers + multiple sources up to 200 or 300 hz (either OB or multi box) + amplifier works correctly (with my yamaha nothing sounds good at low volume).
Can measure the difference in the impulse response because of the multi-source addition but frequency response is pretty close to the same overall.
I got nothing more to add good luck all and thanks for the tips 🙂.
Remember that Qms is only a derivative of resistance (Rms) AT RESONANCE.
Resonance is the "sloppy" area of a driver's motion, and resistance there is the driver's weak point.
Rms is the better parameter to look at.. BUT remember, that it is a composite that is mostly about the spider and NOT the surround.
The surround is usually what abbreviates that sub millimeter stroke range, so no parameter really provides the necessary clue to mechanical driver resistance at extremely low excursion. 😱
Qms as a derivative of Rms can be useful, Rms should be more useful, but neither are the "magic bullet".
Resonance is the "sloppy" area of a driver's motion, and resistance there is the driver's weak point.
Rms is the better parameter to look at.. BUT remember, that it is a composite that is mostly about the spider and NOT the surround.
The surround is usually what abbreviates that sub millimeter stroke range, so no parameter really provides the necessary clue to mechanical driver resistance at extremely low excursion. 😱
Qms as a derivative of Rms can be useful, Rms should be more useful, but neither are the "magic bullet".
😡. That makes it hard when looking at datasheets........probably why there are outliers when testing drivers.Im not sure what "Rms"is. Can U explain?
BTW one of the most pronounced examples of the effect of the surround I have ever heard was a 15 inch woofer that had a vynl based foam surround. I believe the idea was good cone termination into the midrange as the cone was designed to be used past 1 khz. This type of surround is highly hysteresis and the bass perf on this woofer was just not good. Always seemed confused and a bit soft /slow. (I kno silly word discriptions but thats all I have) I coated the surround with a very low loss rubber. The change was emediatly noticable. It was an obvious difference. Tunefull, dynamic, livley. This even at VERY low volume with speaker held up to ear and while the Fs changed a bit the overall frq response in the passband I was using (below 500hz) it was basically the same. Also this woofer was tested in 3 situations. Closed box passive crossed over at 400 hz, open baffle passive crossed at 400hz, and even as a car sub crossed active at 100hz. The result was noticable in all 3.
While I would agree that such things can and often are a combination of things, I have just too many similar real world hands on experiences with this one to say its a small contributor.
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Thanks marco
I wonder if one of the issues here is that Hysteretic properties are not linear with freq? AND as well the geometry of the component can have a solid effect?
I suspect both the spyder and surround play a similar role to each other in the mentioned respect particularly at low freq. as they are both being distorted in cone motion.
In one example I sited I changed only the surround from high loss to low loss.
In another experiment on a similar woofer with the same character I cut the spider out and replaced it with two tensioned kevlar threds in an X pattern giving a very low loss spider. The result was the same as the woofer where the surround was modified.
I wonder if one of the issues here is that Hysteretic properties are not linear with freq? AND as well the geometry of the component can have a solid effect?
I suspect both the spyder and surround play a similar role to each other in the mentioned respect particularly at low freq. as they are both being distorted in cone motion.
In one example I sited I changed only the surround from high loss to low loss.
In another experiment on a similar woofer with the same character I cut the spider out and replaced it with two tensioned kevlar threds in an X pattern giving a very low loss spider. The result was the same as the woofer where the surround was modified.
Of course they aren't.
But usually the lumped parameters at the resonance frequency (among which Rms, Qms, etc.) are all we have to go by, and I think we can still use them to provide at least some useful indications of the likely behaviour of a particular Woofer over most of the low frequency range.
Yes.
Hi,
My 2 cents. Look for a full ranger. The criteria that makes a full ranger ( or a widebander) able to reproduce high frequencies are also the same parameters quite often mentioned. Low loss, low mass and powerful motor..
One aspect, I think not fully discused is the effect of mass (Mms). A speaker in physics term is a simple harmonic system, a mass on the end of the spring. ( which is why you have things like spring constants (Cms) etc). What a simple harmonic system wants to do is to produce sine oscillations. So when a mass gets heavy it will more likely produce a sine wave even when you are not feeding it a sine wave. They store too much energy in them.
My thoughts on how to quantify it. I did a simple experiment on my speakers once. Using the volume control of my minidsp and my microphone positioned about an inch from the speaker. I gradually drop the volume at a time. My Faitalpro 3fe22. Could play a flat frequency responce at a -50 db volume. We are talking of power setting less than a mW. I haven't managed to get a chance to try it in other speakers. But I am quite surprised that a loudspeaker could produce any sound at those power levels.
Oon
My 2 cents. Look for a full ranger. The criteria that makes a full ranger ( or a widebander) able to reproduce high frequencies are also the same parameters quite often mentioned. Low loss, low mass and powerful motor..
One aspect, I think not fully discused is the effect of mass (Mms). A speaker in physics term is a simple harmonic system, a mass on the end of the spring. ( which is why you have things like spring constants (Cms) etc). What a simple harmonic system wants to do is to produce sine oscillations. So when a mass gets heavy it will more likely produce a sine wave even when you are not feeding it a sine wave. They store too much energy in them.
My thoughts on how to quantify it. I did a simple experiment on my speakers once. Using the volume control of my minidsp and my microphone positioned about an inch from the speaker. I gradually drop the volume at a time. My Faitalpro 3fe22. Could play a flat frequency responce at a -50 db volume. We are talking of power setting less than a mW. I haven't managed to get a chance to try it in other speakers. But I am quite surprised that a loudspeaker could produce any sound at those power levels.
Oon
"My 2 cents. Look for a full ranger. The criteria that makes a full ranger ( or a widebander) able to reproduce high frequencies are also the same parameters quite often mentioned. Low loss, low mass and powerful motor.."
Well the woofers I have goten this low freq perf on were high loss cones and whipy motors. I cant speak on midrange changes but the low freq were clearly different with low loss suspensions
As far as low volume clarity in the mid and up freq I would agree we want a low loss cone/dome regardless of the suspension type
Well the woofers I have goten this low freq perf on were high loss cones and whipy motors. I cant speak on midrange changes but the low freq were clearly different with low loss suspensions
As far as low volume clarity in the mid and up freq I would agree we want a low loss cone/dome regardless of the suspension type
Not that simple.
A "full range" driver is designed to strike a compromise between moving some air at mid-low frequencies and having an extended frequency response at the high end. As a result, it is typically electrically overdamped, and won't produce much bass at all unless back-loaded by a large horn (which places a large additional acoustical load on the rear face of the diaphragm, thereby decreasing damping at low frequencies).
For a dedicated woofer, instead, high frequency extension is no longer a design goal, and the electromagnetical force factor (BL^2/Re) is adjusted so as to produce "optimal" damping of the low frequencies for a given moving mass (Mms).
In fact, perhaps somewhat counter-intuitively for some, the moving mass per se doesn't mean anything. It's the ratio of the electromagnetical force factor to the moving mass that matters:
Electrical damping = "Efficiency Bandwith Product" =
= (Fs / Qes) = 1/(2*Pi) * (BL^2/Re) / Mms
Once the desired electrical damping is fixed - which by and large determines a woofer's achievable low frequency extension - then the (typically much lower) mechanical damping (i.e., Fs/Qms) comes into play.
THE ISSUE AT HAND IN THIS THREAD is that while the latter's contribution to the woofer's total low frequency damping is often neglibible...
Total damping = (Fs / Qes) + (Fs / Qms)
...at the same time, the mechanical damping still appears to have an important role in determining NOT the quantity, but the quality of the reproduced low frequencies at low listening volumes.
My Jordan Eikonas have an aluminium cone and the rubber surround is the softest I've come across, almost sexy soft! Anyhow....they sound very good at low levels
".at the same time, the mechanical damping still appears to have an important role in determining NOT the quantity, but the quality of the reproduced low frequencies at low listening volumes."
exactly
I would add though that this low freq quality was heard at both low and high volume
exactly
I would add though that this low freq quality was heard at both low and high volume
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