The Much Coveted Jump Factor - Friend or Foe

[cjfrbw]

The problem with these loosey goosey audio terms is they are in the ear of the beholder, and mean so many different things to different listeners.
This jump factor term was an audio critic generated term that I recall was used in some narrow context to glorify high slew rate, high damping (lots of feedback), high power amplifiers. The presumption was that such an amplifier's performance would translate into shock and awe on rapid massed instruments (or possibly closely mic'd blats) without dynamic compression, limiting or clipping. I'm not even sure any other distortion issue was even included. Whether the term has diversified to mop up a variety of issues, I don't know. Of course, it is still a matter of opinion and controversy whether these 'goals' are always going to sound good in a system.

Some of what the OP seems to be describing is dynamic pumping caused by leading edge distortion and compression effects, which do not sound like exactly the same thing. We also have amplifier manufacturers who are not set on a goal of zero distortion, but like to mix especially second and third harmonics like witch's oils to enhance the psychoacoustic experience. Not everybody believes that harmonics are bad things.

Race cars have 0-60 times, an audio system might have a 0db to 120db instantaneous rise time. Of course, with compression et alia, there are very few unfettered dynamic recordings and very few systems that could reproduce them to their full 120 db transient effect.

 

[Folsom]

There are a lot of reasons that the experience stehno has could be more how he describes with his stereo/stereos for him, and less for us in ours.

 

[the sound of Tao]

There’s been some great descriptions in this thread of the illusive jump factor.

Great musicians like great artists play with time and space. This is possible because for us consciousness is non linear. Our minds only recomposit our experiences to appear linear so that we can connect and correlate the threads but our perceptions are always slipping/dancing/jumping between that which was, that which is and that which may be.

Jump factor for me is like a super heightened sense of immediacy, an irrepresible near physical engagement in moments of near shock... and awe.

A temporal rollercoaster of annnn-tisss-iiiipashn,
unexpected experience and moments of shattered retention. Music that scales up in waves is more comfortably exciting, crescendo that crash more suddenly into us put us onto the very edge of the seat.

The thrill that comes from macro moments can also be in micro moments with the kinds of directed appearances of sound that catch our attention and dart with zeal across the stage. When the wave comes and it has travelled before expection and anticipated scaling up gets to us earlier, suddenly and greater than anticipated that is also part of that jumpy immediacy.

Some systems can only plod. This is for me one of the great audio deal breakers. Immediacy and the capacity to jump, when musical shifts can be seemingly instantaneous and quicksilver is a quality along with coherence, natural tone and timbre... immediacy and timing, it’s all in the timing of musicians that makes the impact and power so unexpected.

Temporal surprises that startle and capture our full attention and shock our perceptions absolutely to the fleet focal point of the music.

That on the edge of the seat near physical immediacy when the music is played with verve and drama, tension and excitement and includes the great moments of the unexpected that make us just follow and don’t allow for any other appreciation or thought than to just listen and experience.

It is rise time and dynamic envelope as others have said tho I’m not sure that jump factor was ever meant to be just quite so literal as the music experiences that physically make us jump out of our seats.

 

[Al M.]

Well said. Yes, music must be exciting first and foremost, and its drama must shine through.

 

[RogerD]

The only time I can remember experiencing jump
Factor is when a instrument is to close to the mic(Simon & Garfunkel Live at Carnegie Hall), movie soundtracks, and either drum whacks or cymbal crashes. These all have large transient peaks. I only recall a piano key strike once. No
To a sax, or any other woodwind. Although a sax can soar or burp and be pretty dynamic. Maybe a trumpet blast...Miles Davis. Also a jazz string bass can be dynamic.
Mostly though I measure dynamic power by the ability of the music to soar when it should or shear power of the bass like a Bosendorfer piano.
I’m sure there other examples.
After while you can get conditioned to some of this. Of course the fun is some abstinence and then the surprise. I think real jump at realistic volume levels is rare like I mentioned before.

 

[KeithR]

Ralph from Atmasphere posted on another forum that most of the SET jump factor is really distortion caused by higher order harmonics when pressed, not actual ability. I am not surprised by this actually as most push SET amps too hard vs the 20-25% of rated power they should be used for (SET amps have increasing distortion with wattage).

 

[Folsom]

I dunno about higher order harmonics specifically, but he's saying the same thing I'm saying... It's a function of the amps as much as the music for a lot of gear.

 

[DaveC]

Here’s a video of a live performance of Tchaikovsky’s 1812 Overture as the cameras pan the musicians (who should experience more jump factor than anybody) and a bit of the audience. This is fairly exhilarating, exciting, and otherwise dynamic performance with horns, bass drums, crashing cymbals, cannons, fireworks, bell towers, the works.

I challenge anybody here to point out a single instance where even one participant or observer appears even once to experience anything even close to YOUR OWN definition of the “jump factor”. How about the musicians sitting about 4 feet in front of the cymbals at the 10:00 min mark? Did they even bat an eye when the cymbals clanged directly behind them?

Lol, everyone's heard the 1812 Overture and knows exactly what's coming next... especially the musicians playing it!

 

[DaveC]

Of course, with compression et alia, there are very few unfettered dynamic recordings and very few systems that could reproduce them to their full 120 db transient effect.

Yup, imo it's often the recording that's the limitation. Recordings are compressed so the average system can play them...

As a musician I've felt this to be one of the largest differences vs live music, and even playing live many instruments are compressed real-time to limit their dynamics. This is one of the biggest issues comparing live vs recorded music.

 

[montesquieu]

"...historically high-end audio has perceived the “jump factor” as a much coveted characteristic and one to pursue " - If that is the case then it's something I'd like to know more about but at this point I don't know what "jump factor" is.

Can't say I'd heard of the term before reading this thread.

It seems on page 1 we are already on several definitions.

 

[morricab]

Ralph from Atmasphere posted on another forum that most of the SET jump factor is really distortion caused by higher order harmonics when pressed, not actual ability. I am not surprised by this actually as most push SET amps too hard vs the 20-25% of rated power they should be used for (SET amps have increasing distortion with wattage).

As Cheever pointed out the perceptability of distortion is SPL dependent. So, if you push a SET too hard and start making a lot of high order harmonics, how problematic that will be depends on how loud it is when that starts happening. So, the problem is really the opposite of what Ralph claims. With a SET suitable speaker you won’t get into trouble from a power until it is loud enough not to make too much impact perceptually. With a SET unsuitable speaker it may become objectionable but I doubt anyone would consider the combo to have great jump factor. There are exceptions with the best SETs giving good dynamics even with moderate sensitivity speakers. Funny thing is that the OTLs have even a narrower compatibility range than SETs and it overlaps quite a bit, so maybe Ralph is trying to backhand his main competition?

 

[microstrip]

Ralph from Atmasphere posted on another forum that most of the SET jump factor is really distortion caused by higher order harmonics when pressed, not actual ability. I am not surprised by this actually as most push SET amps too hard vs the 20-25% of rated power they should be used for (SET amps have increasing distortion with wattage).

Can you give us a link to this comment? Some reviewers consider that Atamasphere OTLs score very well in jump factor, and as there are very different definitions of "jump factor" I would like to read his words and definition of jump factor.

 

[KeithR]

I didn’t think it kosher to cross post forums, but you can do a search on Audiogon - it was a few days ago.

 

[microstrip]

I didn’t think it kosher to cross post forums, but you can do a search on Audiogon - it was a few days ago.

The only recent post I could find from Ralph on SETs at audiogon was on SET sound at very low levels, where he admits they excel, can you tell me the date of the one you referred? Ralph posts a lot of interesting information at Audiogon!

IMHO referring to a precise post in another forum is not cross posting, it is just good and fair referencing.

 

[KeithR]

Very well- this is Ralph’s post (mods feel free to delete if inappropriate):

“What you are up against is that to make more power, SETs have to sacrifice bandwidth. 300b amps are at about the limit of what can be considered 'hifi'; even then its very difficult to get them to go from 20Hz to 20KHz and most of them don't.

Because a horn system is about the only thing that has enough efficiency (or in some cases, single driver full range speakers like Lowther) to work with a 300b, this isn't too much of a problem because most horns and full range drivers can't make much bass below 40-60 Hz anyway.

Now of course you will hear of a lot of people running speakers that are less than the sort of efficiency you need (+99dB) but they really aren't getting the best performance out of their amps as a result unless they are listening in a smaller room. To really take advantage of what SETs bring to the table, you really don't want to push them past about 20% or so of full power, otherwise they start sounding 'dynamic' but this is entirely caused by distortion. BTW, once you know this fact, its easier to hear that such is the case so I may have ruined it for you- if so, my apologies.


The ear uses higher ordered harmonics to sense sound pressure, and SETs generate more higher ordered harmonic distortions once they start getting over about 20-25% of full power. Since music has lots of transients, as you turn up the power these harmonics initially are showing up on the transients of the music- and that is how they sound more 'dynamic' than one would expect for a lower powered amp.


If you really need more power (if a more efficient speaker is out of the question), IMO/IME you are far better off looking for a lower powered push-pull tube amplifier. You'll hear more detail and bandwidth won't be a problem. Most such amps won't be as lush since they don't make as much 2nd order harmonic distortion, but overall they stand a chance of being more musical than a larger SET.”

 

[microstrip]

Very well- this is Ralph’s post (mods feel free to delete if inappropriate):

“What you are up against is that to make more power, SETs have to sacrifice bandwidth. 300b amps are at about the limit of what can be considered 'hifi'; even then its very difficult to get them to go from 20Hz to 20KHz and most of them don't.

Because a horn system is about the only thing that has enough efficiency (or in some cases, single driver full range speakers like Lowther) to work with a 300b, this isn't too much of a problem because most horns and full range drivers can't make much bass below 40-60 Hz anyway.

Now of course you will hear of a lot of people running speakers that are less than the sort of efficiency you need (+99dB) but they really aren't getting the best performance out of their amps as a result unless they are listening in a smaller room. To really take advantage of what SETs bring to the table, you really don't want to push them past about 20% or so of full power, otherwise they start sounding 'dynamic' but this is entirely caused by distortion. BTW, once you know this fact, its easier to hear that such is the case so I may have ruined it for you- if so, my apologies.


The ear uses higher ordered harmonics to sense sound pressure, and SETs generate more higher ordered harmonic distortions once they start getting over about 20-25% of full power. Since music has lots of transients, as you turn up the power these harmonics initially are showing up on the transients of the music- and that is how they sound more 'dynamic' than one would expect for a lower powered amp.


If you really need more power (if a more efficient speaker is out of the question), IMO/IME you are far better off looking for a lower powered push-pull tube amplifier. You'll hear more detail and bandwidth won't be a problem. Most such amps won't be as lush since they don't make as much 2nd order harmonic distortion, but overall they stand a chance of being more musical than a larger SET.”

Thanks - IMHO jump factor is not related to this increased apparent loudness - on the contrary jump factor relies in very clean signal along all the dynamic range.

As Ralph says a few lines bellow your quote https://forum.audiogon.com/discussi...-upgrading-a-300b-set-amp/post?postid=1697710

"Yes- I get what the allure of the SET is all about. That inner detail they are known for comes out of the fact that as power levels are reduced, the distortion decreases to unmeasurable. When the distortion is gone, detail is revealed. There aren't many push-pull amps for which that is the case, but there are a few.

The problem is that you can't get much bigger than the 300b; people have built SETs with dual 300bs that aren't too bad but they are only 3dB more powerful (which is to say, twice the power); the problem is that the way the ear hears, 3dB just isn't that much louder "

Again IMHO SETs only have jump factor at low powers. Jump factor needs natural detail. As always, YMMV.

 

[Folsom]

Interesting. I find jump factor increases with a cleaner output as well. It sounds less like dry/plastic fuzz/mud.

 

[stehno]

It still doesn't seem there's much of a consensus on exactly what the jump factor is or what exactly causes it (live music), or when (live music). Startling, jolting, jumping are some of the terms tossed around. I've included the term "emotional impact" because I don't think there absolutely has to be a real physical response everytime when/if a jump factor event occurs.

RogerD mentioned jump factor in movies and home theater several times. But that really shouldn't count as it seems Hollywood would like nothing more than to shock and awe us with every event in every movie. At the very least, Hollywood has little / nothing to do with high-end playback music.

DaveC seems to imply that whatever jump factor means to him, it can only occur when one is surprised or not conditioned and he used the 1812 Overture as his reference since everybody and their mother has heard it. So maybe DaveC is implying that the jump factor can only occur on new unfamilier music. I don't buy that. To use an extreme example. If a .45 cal pistol was fired 5ft from my ears 50 times a day every day, I suspect my body would express an emotional impact every time whether blind-folded or not indoors or outdoors. On the other hand if the distance were 75ft. from my ears I may not be emotionally impacted even once.

Those who admit to experiencing this jump factor during a live performance seem to indicate it is a rare event. But even they seem elusive as to the actual frequency they encounter it. Does rarely heard imply a handful of times in one's entire lifetime, or a handful of times per live event?

With regard to playback music and jump factor, it does seem every few posts that distortions of some sort either directly or indirectly may come into play.

Efficient speakers entered into the discussion several times and based on my limited experience, I really don't see that as an issue worth consideration. At least not from my very limited experience. I think about the time back in 2006 when I owned a fairly highly touted McCormack DNA-2 Rev A amp at 300wpc@8ohm (1200wpc@2ohm). Peter Moncrieff of IAR in 1998 rated the DNA-2 Ltd Annerversary Edition amp (which I also owned) as the most musical and fastest/quickest SS amp among the 30 or 40 he evaluated and Rev A was significantly better. Anyway, I received from a distributor a pair of nuforce 9 SE Class D 160wpc mono-block amps he was begging me to audition. When I unboxed 7 lbs. amps I thought they were a joke but immediately upon install and especially after burn-in the nuforce amps were significantly more refined and musical across the board. Especially in the bass regions where the bass was deeper, tighter, more well-defined and my speakers at the time were among the very least efficient at 86db@4ohm. I immediately sold the DNA-2 Rev A and became a dealer for nuforce.

Also, one ingredient that seems for the most part overlooked in this topic (and in most other topics) is listening volume levels. I've mentioned that on average my listening level is most always around 96db - 98db. It's been my experience that the vast majority of those subscribing to high-end audio listen at db levels significantly lower than that. That I do not get. Why would audiophiles be trying to replicate anything in a live performance if they're not even willing to listen to playback music at roughly the same levels? In some ways, that seems like driving a top fuel dragster down the quarter mile strip at half-throttle but expecting to still get sub-4 second ET and 300+ mph.

To the best of my knowledge about 2 generations ago audiophiles started training themselves to listen at lower listening volumes because historically the distortions of our playback systems could be overwhelmingly unpleasant and unmusical. But in recent years it seems most everybody claims to know how to lower distortions so surely things have progressed but I've not seen any real evidence of volume levels increasing to higher more like live performance db levels.

Anyway, I find it difficult to believe that anybody can really expect to intelligently discuss comparisons about most any high-end audio topic if we aren't even willing to reach some common ground here listening volume-wise. But I digress.

 

[the sound of Tao]

It still doesn't seem there's much of a consensus on exactly what the jump factor is or what exactly causes it (live music), or when (live music). Startling, jolting, jumping are some of the terms tossed around. I've included the term "emotional impact" because I don't think there absolutely has to be a real physical response everytime when/if a jump factor event occurs.

RogerD mentioned jump factor in movies and home theater several times. But that really shouldn't count as it seems Hollywood would like nothing more than to shock and awe us with every event in every movie. At the very least, Hollywood has little / nothing to do with high-end playback music.

DaveC seems to imply that whatever jump factor means to him, it can only occur when one is surprised or not conditioned and he used the 1812 Overture as his reference since everybody and their mother has heard it. So maybe DaveC is implying that the jump factor can only occur on new unfamilier music. I don't buy that. To use an extreme example. If a .45 cal pistol was fired 5ft from my ears 50 times a day every day, I suspect my body would express an emotional impact every time whether blind-folded or not indoors or outdoors. On the other hand if the distance were 75ft. from my ears I may not be emotionally impacted even once.

Those who admit to experiencing this jump factor during a live performance seem to indicate it is a rare event. But even they seem elusive as to the actual frequency they encounter it. Does rarely heard imply a handful of times in one's entire lifetime, or a handful of times per live event?

With regard to playback music and jump factor, it does seem every few posts that distortions of some sort either directly or indirectly may come into play.

Efficient speakers entered into the discussion several times and based on my limited experience, I really don't see that as an issue worth consideration. At least not from my very limited experience. I think about the time back in 2006 when I owned a fairly highly touted McCormack DNA-2 Rev A amp at 300wpc@8ohm (1200wpc@2ohm). Peter Moncrieff of IAR in 1998 rated the DNA-2 Ltd Annerversary Edition amp (which I also owned) as the most musical and fastest/quickest SS amp among the 30 or 40 he evaluated and Rev A was significantly better. Anyway, I received from a distributor a pair of nuforce 9 SE Class D 160wpc mono-block amps he was begging me to audition. When I unboxed 7 lbs. amps I thought they were a joke but immediately upon install and especially after burn-in the nuforce amps were significantly more refined and musical across the board. Especially in the bass regions where the bass was deeper, tighter, more well-defined and my speakers at the time were among the very least efficient at 86db@4ohm. I immediately sold the DNA-2 Rev A and became a dealer for nuforce.

Also, one ingredient that seems for the most part overlooked in this topic (and in most other topics) is listening volume levels. I've mentioned that on average my listening level is most always around 96db - 98db. It's been my experience that the vast majority of those subscribing to high-end audio listen at db levels significantly lower than that. That I do not get. Why would audiophiles be trying to replicate anything in a live performance if they're not even willing to listen to playback music at roughly the same levels? In some ways, that seems like driving a top fuel dragster down the quarter mile strip at half-throttle but expecting to still get sub-4 second ET and 300+ mph.

To the best of my knowledge about 2 generations ago audiophiles started training themselves to listen at lower listening volumes because historically the distortions of our playback systems could be overwhelmingly unpleasant and unmusical. But in recent years it seems most everybody claims to know how to lower distortions so surely things have progressed but I've not seen any real evidence of volume levels increasing to higher more like live performance db levels.

Anyway, I find it difficult to believe that anybody can really expect to intelligently discuss comparisons about most any high-end audio topic if we aren't even willing to reach some common ground here listening volume-wise. But I digress.

Stehno, I’m especially not sure why you are discounting (high?) efficiency speakers especially if you have limited experience. If dynamics were a factor for some people’s correlation with what they consider jump factor to be (and I certainly also ascribe to this) then high efficiency speakers (horns come to mind here especially) could certainly be of relevance.

I also don’t understand where you evidence legions of scary audiophiles historically TRAINING themselves to listen at specific volumes. My heavens I’m glad I missed that part of the journey.

And the day that someone determines that there is an actual dB value for correct listening and that anyone who doesn’t listen at the volume is therefore somehow invalid or has less understanding then we should all consider getting out of this hobby and just topping ourselves.

Seriously dude... how desperate are any of us to be sooo correct we can’t see that there is already way too much objective argument over what is essentially subjective and really just more BS in this hobby where soooo many are pretending to know what’s really going on when the best parts of this experience lays in the marvellous mystery of human perception. As music lovers and gear heads we could all do with a bit of chill and just a dash of LATITUDE. Arbitrary rules and constantly arguing over noise with more noise isn’t fun. It’s all distortion, this is an illusion. There is no great and binding truth other than we should just enjoy the diversity of all our experiences and stop trying to tell people that their version of the experience isn’t true because it doesn’t align with ours. Said with peace and love and good music playing all the while on my SET amp through my high efficiency horn speakers and getting ready to factor in another jump... whatever and wherever that may be. Peace out brother and enjoy the epic joys of the great and the unknowable.

 

[morricab]

Very well- this is Ralph’s post (mods feel free to delete if inappropriate):

“What you are up against is that to make more power, SETs have to sacrifice bandwidth. 300b amps are at about the limit of what can be considered 'hifi'; even then its very difficult to get them to go from 20Hz to 20KHz and most of them don't.

Because a horn system is about the only thing that has enough efficiency (or in some cases, single driver full range speakers like Lowther) to work with a 300b, this isn't too much of a problem because most horns and full range drivers can't make much bass below 40-60 Hz anyway.

Now of course you will hear of a lot of people running speakers that are less than the sort of efficiency you need (+99dB) but they really aren't getting the best performance out of their amps as a result unless they are listening in a smaller room. To really take advantage of what SETs bring to the table, you really don't want to push them past about 20% or so of full power, otherwise they start sounding 'dynamic' but this is entirely caused by distortion. BTW, once you know this fact, its easier to hear that such is the case so I may have ruined it for you- if so, my apologies.


The ear uses higher ordered harmonics to sense sound pressure, and SETs generate more higher ordered harmonic distortions once they start getting over about 20-25% of full power. Since music has lots of transients, as you turn up the power these harmonics initially are showing up on the transients of the music- and that is how they sound more 'dynamic' than one would expect for a lower powered amp.


If you really need more power (if a more efficient speaker is out of the question), IMO/IME you are far better off looking for a lower powered push-pull tube amplifier. You'll hear more detail and bandwidth won't be a problem. Most such amps won't be as lush since they don't make as much 2nd order harmonic distortion, but overall they stand a chance of being more musical than a larger SET.”

Ralph’s post has some patent falsehoods in it, particularly about being limited to a 300B and getting wide bandwidth. There are a number of significantly higher output SETS with bandwidths from say 10-15Hz.to 50-60khz at full rated power.

He is right that higher order harmonics start to grow with high power output but what is important is whether the pattern stays roughly the same or if the high orders increase faster than the second, third and fourth . The ratios matter. The pattern in many amps changes not only with power but also frequency and this is detrimental to sonic quality and believability

Ralph is also not taking into account that most of PP tube amps have pretty high distortion at all powers and at low power and SPL it is most critical and at high power/SPL it is the least critical. I will state again, Sensitivity to distortion is SPL dependent.