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Speaking of advertising woo... transients...

Discussion in 'Amps and Cabs [BG]' started by JimChjones, Nov 17, 2018.

  1. JimChjones


    Aug 6, 2017
    SE England
    Just reading the ampeg advertising for their 8*10s, and they are saying that 10s react far quicker to transients than 12s and 15s. Is there really any logic to this or is it just more advertising woo... A 15in engine and cone is quite capable of reacting fast enough to deliver 1.5khz or higher signal, what transients can possibly require the speaker to respond any faster than that? And what do they really mean by transients anyway? Surely all the speaker knows is its getting a wave form which it does its best to respond to? Yeah sure by their nature 10s are delivering a few khz higher than a 15, at least on axis, but what has that to do with transients?
    Pbassmanca likes this.
  2. Kro

    Kro Supporting Member

    May 7, 2003
    New Jersey
    I have heard it stated before, from those with far more experience than myself, that all else being equal (which we know is never the case) the driver with less moving mass will respond marginally faster.

    How much of a difference that makes is debatable, and again, I'd expect that speaker size does not necessarily equal lighter.

    That is officially every shred of information that I have in my head on that subject. Interested to hear the thoughts of others that I hope will weigh in, as I find it an interesting topic.
    Pbassmanca likes this.
  3. agedhorse

    agedhorse Supporting Member Commercial User

    Feb 12, 2006
    Davis, CA (USA)
    Development Engineer-Mesa, Product Support-Genz Benz
    Everything related to transient response is contained within the bandwidth (or frequency response) information. The faster the transient response, the greater the bandwidth.

    Bandwidth is mostly affected by motor strength, moving mass, cone shape/stiffness and damping. Size mostly affects pattern uniformity, as the size increases interference can degrade response.
  4. fdeck

    fdeck Supporting Member Commercial User

    Mar 20, 2004
    Madison WI
    HPF Technology LLC
    Here's a way that I think about it, FWIW. This is based on working through the speaker modeling equations and seeing how the parameters combine with one another. I got interested in this stuff, purely as an intellectual exercise, but it led me to a better understanding of how speakers work.

    Sure, the bigger cone is heavier, but in order to maintain decent frequency response, the motor has to be made proportionately stronger. There's a factor BL/m which shows up in the frequency response equation, which suggests that you can balance a change in mass with a proportionate change in motor strength (B is magnetic field and L is the length of wire suspended in the field). There are a couple more details (spring constant and damping factor also have to change), but this is the gist of it.

    But... the "speed" that you actually hear is the sound pressure wiggling back and forth in your ear canal, and this is related to the linear speed of the cone, and its frontal area. When you account for the area of the cone, then the 15" driver actually wins the speed war at your ears. And this is apparent in the fact that 15" systems tend to have higher sensitivity than 10" systems when both are competently designed to have similar response curves.

    Like @agedhorse says, transient response and frequency response are really two sides of the same coin in speakers.
    BassikBrad, bobcruz and Kro like this.
  5. Wasnex


    Dec 25, 2011

    The normal argument I see is sealed cabs have "better" phase/group delay characteristics so the lows are perceived as faster.

    Here's a thread that cites an article related to this claim:
    Bass alignment methods and group delay

    With the right type of measurement equipment (for example SMAART) I believe you can easily see the difference, but I don't feel the difference when I play.

    My personal opinion is an Ampeg 810E sounds and feels extremely sluggish because it doesn't have enough high frequency extension to communicate what feels fast to me. I would describe my Greenboy Dually pretty much the same way and it is a ported design.

    My Dually is loaded with Faital 15PR400s, but if you look at the 45 degree off axis response, the highs drop off pretty significantly above 3kHz. 15PR400 by FaitalPRO

    I believe 3kHz is also about where the 810E starts cutting off.

    I have run an 810E and the Dually as the woofer in a biamped rig and both felt fast when I added a mid-high pack to extend the high frequency response.
  6. Rick James

    Rick James

    Feb 24, 2007
    New Jersey
    It is. When I see claims like that I have to wonder if whoever wrote even knows what transient response is. Either they don't or they're assuming that whoever is reading it doesn't.
    In blind testing with ported and sealed cabs EQ'd for identical response listeners can't tell one from the other. The differences in phase response and GD are pretty obvious when charted, but this is just one of the many instances where what can be charted can't be heard.
    agedhorse and Wasnex like this.
  7. fdeck

    fdeck Supporting Member Commercial User

    Mar 20, 2004
    Madison WI
    HPF Technology LLC
    Indeed, if you EQ the systems, the EQ will have its own transient / GD behavior.
    agedhorse and Wasnex like this.
  8. ThisBass


    Aug 29, 2012
    Transients is a thing that (unfortunatelly) is poorly understood by most of all engineers.
    Try to imagine the sound of a ballon that explodes. Rather than harmonics which can be described by Fourier analytics in this case (the exploding ballon) can be roughly discribed as a dirac impulse which is nothing but a spike which is very short in the time domain. Interstingly those spikes generate a frequency spectrum which starts at DC, shows a peaking in the frequency domain, and rolls off in level with higher frequency but spreads to infinite frequency.
    Roughly the genertaed frequency response spectrim looks very familar to Gaussian bell curve.

    The "quicker" a speaker can react on those "transients" the better the speaker can reinforce the "sound" of a exploding balloon.

    You may ask a question what the hell a bass guitar might ever have to do with an exploding balloon?

    Just the moment we hit the string and the string tries to "start" to "oscillate" this moment is kind of a process which is (roughly) comparable with an exploding ballon, thus the string really does generate "transients" and generates a spectrum which is out of order versus "typical" harmonics schemes.

    The decay envelope of an oscillating string as well does generate "transients" thus generates a spectrum way off from "harmonics" but with a different spectrum characteristic versus the initial process when we "hit" the string.

    There is no cabinet on this planet available which could really perfectly reinforce the sound of an exploding ballon or reinforce the sound of a breaking branch but, the better a speaker can "react" on transients the better the speaker can reinforce typical "transient" sound events.

    Last edited: Nov 17, 2018
  9. micguy


    May 17, 2011
    Transient response and freq response are intrinsictly linked, as has been covered. The question I have is: Do you want to hear it?

    My pedalboard has a lowpass filter on it because... less bandwidth sounds better, especially if there’s dirt involved. All the folks that don’t like tweeters or that insist on micing their cabinet are also fans of limited bandwidth.
  10. cazclocker

    cazclocker My social skills are rapidly dwindling.

    Oct 24, 2014
    Newton, Kansas
    I used to drive through parts of Skid Row in L.A. on my way to certain gigs. Neither my amps nor my cabs reacted negatively to any transients, at least not that I could tell.
  11. BogeyBass


    Sep 14, 2010
    But yet transients are better.

    It's a sealed system

    People that are to sissy to move a 810
    Might still convince themselves that it's not.

    Way before I spend 300 on a wittle filter.
    I'll just drop another 810 on stage.

    Most the amps I use already have natural or designed high pass.

    Limited bandwidth and punch is perfect for distortion. I've been torturing 810s for years with fuzzy Velcro sustain for long time.

    Most amps overheat before the 810 even sneezed a sign of complaints.

    On axis off axis or doing keg stands lol
    Last edited: Nov 17, 2018
  12. agedhorse

    agedhorse Supporting Member Commercial User

    Feb 12, 2006
    Davis, CA (USA)
    Development Engineer-Mesa, Product Support-Genz Benz
    Sounds like it's time for a prescription refill...
  13. beans-on-toast

    beans-on-toast Supporting Member

    Aug 7, 2008
    You can define speaker cabinet transient ad copy as a momentary lapse of reason.
    agedhorse likes this.
  14. BogeyBass


    Sep 14, 2010
    I'll agree it is pretty cheesy.
    I chuckle a little when I read ampeg add copy lol
  15. Bass reproduced through highly capable tens layed out in squares instead of columns lose a great deal of intelligibility in the midrange off axis.
  16. Thumpin6string

    Thumpin6string Supporting Member

    Apr 25, 2013
    Redding CA
    I've not heard it put that way as transient response, but I've heard many times and have experienced that 10s are punchier. Maybe that is what they are referring to? My Epifani UL410 smacks you upside the head no matter what amp I run through it. None of my 12s or 15s ever did that. Hey, but what do I know? I'm just a dumb old bass player.:bassist:
  17. nilorius


    Oct 27, 2016
    Riga - Latvia
    I think it's just an advertising woo.
  18. agedhorse

    agedhorse Supporting Member Commercial User

    Feb 12, 2006
    Davis, CA (USA)
    Development Engineer-Mesa, Product Support-Genz Benz
    Not necessarily true, the mid radiating pattern may be different but that doesn't make it better or worse.
  19. beans-on-toast

    beans-on-toast Supporting Member

    Aug 7, 2008
    At some point, good sounding 10” bass speakers were elusive. That changed and manufacturers were quick to adopt them and they became popular. Before that, there wasn’t much of a choice, Ampeg used a 30W speaker in the early 810’s.

    Technology advancements opens up new possibilities.
    agedhorse likes this.

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