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What the heck is a transient?

Discussion in 'Amps and Cabs [BG]' started by Nick Gann, Jan 12, 2004.


  1. Nick Gann

    Nick Gann Talkbass' Tubist in Residence

    Mar 24, 2002
    Silver Spring, MD
    I have never heard this word used to describe amps or sound until I look over the ads and posts for the new BBE BMAX preamp, which seem to use "transients" as the new magic word.

    This quote is from Judd from BBE:

    "I think the reason folks have gravitated to the BMAX is not price alone but also the very open sound of it and the quickness of its response to fast transients. "

    So, what is a transient, how does it effect sound, how can I tell a fast one versus a slow one, etc.?
     
  2. Munjibunga

    Munjibunga Total Hyper-Elite Member Gold Supporting Member

    May 6, 2000
    San Diego (when not at Groom Lake)
    Independent Contractor to Bass San Diego
    Transients are sounds (or voltages) that come and go very quickly. Another word often used for transient is "spike." If you pop or slap a string, it produces a sound that is there then gone very quickly. That's a transient. Some electronic equipment cannot react quickly enough to accurately reproduce these transients. BBE is bragging that theirs can.

    Transients are not necessarily a good thing. If you turn on your power amp first, then turn on other devices in the chain (like, say, a mixer or an effect), it can produce a speaker-damaging POP. That's a bad transient. Speakers have a tough time dealing with high-energy transients.

    More than you wanted to know, probably.
     
  3. Nick Gann

    Nick Gann Talkbass' Tubist in Residence

    Mar 24, 2002
    Silver Spring, MD
    Nope, thats just about right :)

    Thanks Munji!
     
  4. Munjibunga

    Munjibunga Total Hyper-Elite Member Gold Supporting Member

    May 6, 2000
    San Diego (when not at Groom Lake)
    Independent Contractor to Bass San Diego
  5. Nick Gann

    Nick Gann Talkbass' Tubist in Residence

    Mar 24, 2002
    Silver Spring, MD
  6. notanaggie

    notanaggie Guest

    Sep 30, 2003
    BTW, if you can hear it, it is in the "audible range".

    Since most any half-decent amp has frequency response to way beyond the audible range, it can reproduce any audible sound. That includes any audible transient.

    So, saying that an amp has excellent transient response is nice. But it doesn't mean automatically that you will hear things from it that other amps can't reproduce. It has a significant "marketing hype" to it.

    If you go talk to the hi-fi audiophile folks, they argue about whether an amp with a frequency response 10 times the audible range is better than one with a response "only" 6 times the audible range.

    And, to some extent there is truth to their arguments, for hifi uses. But for bass amps, it is stretching a point.

    If it sounds good it is good. Good rule.
     
  7. judd levison

    judd levison

    Jun 2, 2003
    hi guys,

    i appreciate all your comments. just my two cents.

    first, i completely agree with notanaggie, let your ears be the judge. one man's ****e is another man's gold.

    with regards to my comments regarding the BMAX' transient response, i made that comment in the context of comparing the BMAX-T to the BMAX. There was no qualatative judgement or boasting made, simply a point of fact that typically our solid-state device responds more quickly to transients. i apologize if this was percieved as a boastful response, again the context was in answer to someone asking me to compare and contrast the differences in sound between the two units.

    if your playing style and preferences go towards solid-state designs (like Glockenklang or EBS) because of thier tigher tone and quicker response, then the BMAX is for you.

    check one out and let your ears be the judge.

    peace
     
  8. technically, a transient is any changing signal. that is why it isn't to use the phrase "fast transient".

    that's not exactly true, either. simply because an amp has frequency response from 20Hz to 20Khz doesn't mean that it can do it well. the power supply dictates a lot of what can and can't be done by the particular device.

    if something is said to have excellent transient response, it's usually a combination of frequency response and clean power supply design that gives it a little more nuance or detail, especially in the higher frequencies.

    robb.
     
  9. judd levison

    judd levison

    Jun 2, 2003
    hi rob,

    the "fast transients" comment was mine and you're correct, it isn't the proper use.

    i stand corrected.

    thanks
     
  10. secretdonkey

    secretdonkey

    Oct 9, 2002
    Austin, TX
    Transients may be prone to setting beverages on your amp, which may spill and degrade the equipment's performance.
     
  11. kmacleish

    kmacleish

    Nov 19, 2003
    Atlanta, GA
    There actually is a spec (slew rate or slewing rate) that somewhat corresponds to "transient response". You see it most commonly on high-end stereo power amps, expressed in volts per microsecond. This does provide a somewhat meaningful measure of how "fast" the amp is.
     
  12. well, it depends. i've listened to samples of both BBE preamps (sounded great, by the way!). if you're referring to the solid state versions generally cleaner and brighter sound, then "fast transients" is the proper phraseology.

    if you were referring to a generally more dynamic and nuance-able sound, however, "fast transient" is not very accurate.

    kmacleish got closer to the idea -- at least for power amps. but slew rate isn't the only factor that makes for a dynamic power amp, one, and two, slew rate is only useful when the power supply is fully charged. when you're playing continuously, the power supply is in a state of flux that may or may not be able to source adequate current to meet the demands of the load for a particular passage.

    it's easy to describe it, but it's hard to spec or analyze it. that doesn't make it invalid, however. since i've listened to the BBE bmax, i'm inclinded to agree with judd that it has good transient response.

    do these explanations make sense or do i need to "de-tech" them?

    robb.
     
  13. Gabu

    Gabu

    Jan 2, 2001
    Lake Elsinore, CA
    I hate it when that happens. ;)
     
  14. Jerrold Tiers

    Jerrold Tiers

    Nov 14, 2003
    St Louis
    News to me, slew rate is always meaningful. Although if the power supply falls a bit under load, the amp output power at clipping also falls, and less voltage swing is available. The slew rate does not change, but the ratio of slew rate to max output voltage gets better.

    Slew rate actually predicts whether reproducing the "transient" will affect reproducing the rest of the signal as well. If slew rate isn't high enough, the attempt to reproduce the transient makes a "transient modulation distortion" (or "intermodulation distortion"), which your ears hear as a lack of clarity. The audiophiles call it T.I.M. or T.I.D., and there are specs and tests for it.

    A "transient" is any signal which has a large amplitude, but which doesn't represent continuous power. It is "transient", here now, but gone away the next moment.

    String pops are a good example. Not much continuous power there, but a lot of peak power demand.

    What a lot of people mean by "transients" is stuff in the signal that can be heard, but that also contains frequencies you can't hear. That messes up some amps, (see T.I.M. above). That's one way transients can cause trouble. Not a big deal with basses, probably, the pickups limit the high frequencies.

    Another thing, if you string pop, you are already playing, so you already are using some of the power capability of the amp, leaving less headroom for a "pop" with a peak of maybe 5 or 10 times the power. That isn't about "transient response" as the BBE folks meant it, but it sure is audible.

    Pretty much any reasonably "pro" amplifier anymore has response that is wide enough to sound good and have "good transient response" (not sound bad if fed transients that you can actually hear). But that doesn't say it has the power headroom for them.

    If the power supply can't handle the demand, that generally shows up as the amp simply clipping (voltage clipping, current clipping, whatever, it all usually sounds bad in SS amps). It isn't strictly about transients.

    In fact, since transients don't represent much continuous power, they don't draw the supply down much. But they need extra voltage headroom.

    The real deal is that if you are already maxed on power, you don't have headroom for transients, never mind the power supply coming down a few percent. The pops get clipped.

    That's one major reason why a big power amp usually sounds so much more open than a lower power head. Nothing much gets clipped, because you are using only maybe 10 or 20 percent of max power and the rest is available for "transients".
     
  15. Munjibunga

    Munjibunga Total Hyper-Elite Member Gold Supporting Member

    May 6, 2000
    San Diego (when not at Groom Lake)
    Independent Contractor to Bass San Diego
    Oh, don't take the "bragging" thing so personally. It's just another word I use for "marketing." I brag about my company all the time (in a tasteful way). BBE didn't seem boastful at all, just informative. Hey, if you're good, you're good.
     
  16. Mud Flaps

    Mud Flaps

    Feb 3, 2003
    Norton, MA
    The word "transience" is used frequently in my English class. It means something that is changeable over time. Maybe transients are simply variations in tone and there impact over a given period. That's my guess.
     
  17. embellisher

    embellisher Holy Ghost filled Bass Player Staff Member Supporting Member

    You're such an ass. Er, I mean goose.:D
     
  18. secretdonkey

    secretdonkey

    Oct 9, 2002
    Austin, TX
    And a fast-moving target to you, sir!

    :D
     
  19. nonsqtr

    nonsqtr The emperor has no clothes!

    Aug 29, 2003
    Burbank CA USA
    Here's a couple of pennies on transients.

    What you "hear" out of the speakers is the net effect of all the electronics in your signal chain, plus the mechanical properties of the speaker (and cab).

    The dynamics of the sound are only as good as the slowest element in your signal chain.

    You can easily check this out on your gear at home. If you pop or pluck one of the strings on your bass (at a reasonable volume level), sometimes you can hear what comes out of the speaker as being a bit "sluggish".

    In solid state gear like preamps, much of this IS related to the slew rate of the chips, and the design of the circuitry (like "servo amps" for instance are specifically designed to maintain an accurate response to rapid transients).

    IMO the overall response of a circuit has a lot to do with the "other" parts, so for instance you can have a really precise chip, but you can put it into a circuit with some capacitance in the wrong place, and easily lose the benefit of the well designed chip.

    Also the speakers are very important. IMO speakers can be the most influential component in the signal chain, in terms of precision in the transient response of the system.

    That being said, some people "like" sluggish amps (or rather, a sluggish "sound"). Typically your solid state amps are going to be more precise than a tube amp, and some people prefer the tube amp because of its fatter more sluggish response.

    It kinda depends on your playing style. If you're going for the Pink Floyd at Pompeii sound, fast electronics probably won't help you (much).

    On the other hand, if your style is cleaner and you like to do a lot of fast accurate slapping, then a clean solid state amp with good dynamics and lots of clean headroom will probably serve you well.

    One caveat though, if you're using a big solid state amp with lots of clean headroom, and the ability to transmit rapid transients accurately to the speaker, it's a good idea to be careful. A good loud "thump" on the low B string can easily cause your speaker cones to try to jump out of their frames! In my lifetime I've seen more than one speaker cone flying all the way across the stage (we're talking twenty or maybe thirty feet).

    This would typically be true for basses with a strong fundamental, especially 5-strings. For instance, I typically have to EQ down the extreme low frequencies on my rig, when I'm using an Alembic Series II bass. The fundamental is so strong on those basses that it causes problems for many of my speakers. There's a compromise to be achieved in that area, 'cause I can hook up big ol' subs that will easily handle the low frequency transients (electronically speaking), but the bigger speakers typically result in a more "sluggish" sound (that's why a lot of people prefer 10" speakers to the big 18's, 'cause they tend to be "snappier" and "punchier").

    All IMO of course (and based on my experience). Just a couple of pennies for free... :)