Do you look at the woofer movement while mixing?

Discussion in 'Mixing & Editing' started by rasputin7095, Aug 23, 2005.

  1. rasputin7095

    rasputin7095 Guest

    I read an article in Sound on Sound, where the writer recommends looking at how much the woofer moves in order to estimate the low bass which you would otherwise not hear. Here's what he says:

    "Anyone listening at home with a system that includes a subwoofer will often come across commercial recordings with all manner of strange problems in the bottom end. Also, the level of very low bass varies tremendously between recordings. The reason for this will be that the mix and/or mastering engineers simply couldn't hear that low in the studios they used. I also find that there are great benefits in being able to see the woofer cones in the mix room. This is one of the reasons I do not recommend using speaker grilles -- try playing Steely Dan's Two Against Nature while watching your monitors to see what I mean!" from: (

    Is this really a valid mixing technique?

    Usually when you hear too much bass, it corresponds to the woofer moving way too much (obviously), and when the woofer moves too much, you hear too much bass. Here's what I don't understand: Is it possible for the bass to sound good, but for the woofer to move way too much?

    The only way I can see this happening is if there's a boosted 20-40 Hz in there for some reason, and you don't hear it, even though it's moving your speaker. But nearfield monitors don't usually go down to 20 Hz!

    A long time ago I was using some cheap M-Audio monitors. Their bottom end started around 60 Hz, but when I put a 20Hz sine wave through them, I could see large and slow movements in the woofer. Does this mean that every speaker DOES go down to 20Hz, or even lower, but we just don't hear it because of the speaker's design, and our natural hearing limitations?
  2. Kev

    Kev Well-Known Member

    Nov 13, 2001
    welcome to monitoring

    speaker systems and rooms can have quite unexpected end results

    I do occasionally look at the woofer while recording and mixing
    ... and just add it to all the other information I have, like meters etc don't over-emphasise or focus on just one piece of info


    it should be noted that when a speaker is at resonance .. the cone excision is great and the acoustic output is low ... it is the point at which the system contains the greatest energy. The port and chamber combine together to give the system a hopefully flat response through the resonance ...
    I've over-simplified that so speaker builders don't jump on me

    most people don't have great systems so here comes a choice you need to make
    who is your end target audience and how will they listen

    the 80's had people using ghetto blasters to mix on ??

    The classical boys don't care and just make the best most truthful recording they can.

    The Rock boys want their CD's louder than the opposition.

    The Jazz boys ... well they just do their own thing ... always.

    speakers just don't keep going lower
    I would put it that most speakers don't go as low as people think
    and certainly not at full power.
    The acoustic output gets very low and the cone excursion go up dramaticaly ... the coil moves out of the magnetic feild and the spider gets strained .... all very non-linear and can change or damage the speaker.

    for most drivers it would be typical to use a them from an octave above it's resonance
    yet we use woofers and sub woofers below resonance

    so much more to the whole story
  3. Davedog

    Davedog Distinguished Member

    Dec 10, 2001
    Pacific NW
    With the Urie 803's I used to measure the bass extrusion. In millimeters of course.....Or was it excursion?...uhh...the length the cone travelled....
  4. johnwy

    johnwy Well-Known Member

    Jan 6, 2003
    Smithtown, NY
    Home Page:
    the only time I looked at the woofers were if they were:

    A) contorting into different shapes... ns-10's were good for this, one engineer I knew was a pro at achieving this.

    B) shooting sparks out of the voice coils ...witnessed this first hand during a loud r&b session, nearly singed my eyebrows (earplugs were in, of course, since my face was about a foot away from the speaker while trying to troubleshoot the problem)

    C) the charred remains of four (yes, four) pioneer tad-1601b's (15" LF drivers for a TAD 2401 system) when the voice coils literally became red hot during an extremely fargin loud rap/hip hop session (I think they had to use a fire extiguisher).... the speakers were fatigued to begin with, the client put them out of their misery, I guess.

    good times
  5. Kev

    Kev Well-Known Member

    Nov 13, 2001
    I had a Drum Fill expire that way
    I was caught half way between stage and FOH desk when the bass guitarist found his on/off switch
    he revelled in 1200 Watts of double 15 bliss .... then flames
    cooooolll he said
    simply had no idea what he had just done.
    I also lost two SM58's one mic-stand and one quality mic-lead that night ... lead singer threw them.
    All part of the act they said.

    AND the band just couldn't understand why I wouldn't hire myself or the rig to them ever again.
  6. JoeH

    JoeH Distinguished Member

    Jun 22, 2004
    Philadelphia, PA/ Greenville, DE
    Home Page:
    That's a great article in SOS magazine, and I took another look at it in order to comment on what you've asked about.

    They make a very good point about knowing what you're hearing, and why, esp when it comes to bass levels: what you may or may NOT be hearing while working on tracks.

    In my own experience, 90% of the systems out there are not giving people the true, full spectrum of hearing, esp when it comes to bass. (Nearfield, 'Studio-in-a-box", self powered stuff) I totally agree with the author when he/she speaks about "wildly differing levels of bass from one recording to another." It's a common problem when you start examining what's below 80 hz in most recordings out there.

    It is slowly starting to get better as more and more folks add subs and surround options to their mixes. (One advancement here, another change there...all for the better, IMHO.) I have indeed found all kinds of bizarre bass levels on other recordings.

    Since I do as much critical listening, mixing and editing as I do mastering, I moved up to a better system to include a subwoofer about six years ago. (I can tell you it seriously changed my entire approach.) I will never mix anything critical without one again.

    Several upgrades later, I have finally found the gear I want/need, and my mixes, in all humility, are what I call "Transportable" in that they sound good pretty much anywhere they go, and my return calls to redo things (or catch some wildly DIFFERENT instrument that is popping out of a mix on someone ELSE's speakers) are becoming non-existant.

    Most people who work at my place still complain that everything sounds BETTER when working at my facility, but they no long complain it sounds "different' when they take it home. They hear more detail, here but not "strange" things back home. ANd, I think that's the goal for anyone's mixing/monitoring system. Accuracy, overall. With the entire sonic spectrum represented.

    That includes the "junk in the trunk" - all the low-end that most people are missing without a sub. You may not hear it, but it wastes power, it muddies up mixes (esp the kind where you DONT KNOW WHY it sounds like $*^t.) I can't tell you how many "Professional" mixes I've heard, done on commerical Big-Label CDs have p's-popping, footsteps, room rumbles, even cars or trucks going by in the background, all because of no low-end subwoofer management during the mixing process. Not all, but a lot of stuff has some very embarassing moments that should have been caught.

    The suggestion to "Watch your speakers moving" is a good idea as a stop-gap IN CASE you dont' have a sub in place. Sadly, it's many times the only way someone would know that there's a lot of low end going on down there, potentially messing up the mid-bass and above. (remember, if your power amp is of limited ablity, it may be wasting a LOT of juice trying to reproduce 20-40 hz material that you don't even know is down there...a good sub will let you hear this, and dial it out if nec.)

    The next question is then, do you want to risk passing that on to the next person - ie: Your client? (And, are you trying to get tons of level out of something that is mysteriously not responding to your efforts? It COULD be a lot of garbage down there messing things up...)

    I have to go back and re-listen to the Steely Dan CD in question. I've found them to be mixed quite well overall, and while they have a lot of extra low end (same as any other rock CD), I don't think they're any worse than some others out there. Honestly, there are a few guys (major players, too) who don't mix with subwoofers, and I personally think they're seriously mistaken (Ok, I think they're idiots. One particular pro actually brags about it) . I'm NOT suggesting using a sub to get ridiculous levels or massage one's privates while working at the console, I'm talking about using it for accuracy, allll the way down.

    Wobbling woofers is a sure sign that something is seriously going on down there, whether you meant it to, or not.
  7. rasputin7095

    rasputin7095 Guest

    I tend to think that most low bass problems can be easily corrected in mastering, given that full-range speakers are used. If the kick drum or bass is too boomy (during mixing), I just shelf (down) or roll off the entire low end, and it usually works.
  8. JoeH

    JoeH Distinguished Member

    Jun 22, 2004
    Philadelphia, PA/ Greenville, DE
    Home Page:
    <<I tend to think that most low bass problems can be easily corrected in mastering, given that full-range speakers are used. If the kick drum or bass is too boomy (during mixing), I just shelf (down) or roll off the entire low end, and it usually works. >>

    See, that's the kind of thinking that keeps mastering engineers busy (and often wringing their hands in frustration).

    You're talking about a "one-size-fits-all" fix for a host of problems. What if it's the bass guitar and not the bass drum? Fix one, you've hurt the other. What if it's a vocal mic track with low end plosives? What about a synth bass track combined with a bass guitar; the synth could easily have a subharmonic that's too loud and you'd never know it without the sub. Fix that after the fact, and you're chipping away at the sound of the bass as well.

    It's better to hear what's going on down there in the first place instead of trying to fix it later. That way, you can work on the important stuff while it's happening, before it's being combined with the other tracks and then a fix becomes a compromise.

    Trust me, mastering guys have enough to deal with than fixing messed up bass levels. They'd much rather you got it right in the first place and give them something they can work with. Sure, a good mastering engineer can fix a lot of stuff, but it's always better to get it right before it's mixed.
  9. rasputin7095

    rasputin7095 Guest

    How low are we talking about? My speakers go down pretty low, so I'm able to hear some nice juicy bass :) Let's say the bass synth is too loud at around 60-70 Hz; if I lower it, I'm not going to just scoop out 60-70, I'll consistently roll it off, all the way down. Most of the "bass punch" is not in the sub-bass, so even if you take out too much sub-bass, it might not make that big a difference.
    Also what I do sometimes is I figure out the frequency of the lowest note the bass guitar/synth plays, and I cut everything below the lowest fundamental. Then the only thing left to deal with is the kick drum, which I mix by bringing the bass all the way down with a shelf, and bring it up slowly until it's good.
    Now, if we're talking about NS-10s, then that's a different story. They have no bass at all. But if you're working on some big Genelecs, Events, or (like I will be soon) on Dynaudios, there's plently of bass.
    Then again, even though I mix once in a while, I'm more of a composer/producer. I tend to focus on creative decisions rather than trying to make it sound good on other peoples' speakers. I trust the mastering guy to "fix it" for me :)
  10. JoeH

    JoeH Distinguished Member

    Jun 22, 2004
    Philadelphia, PA/ Greenville, DE
    Home Page:
    Kev wrote: I've over-simplified that so speaker builders don't jump on me most people don't have great systems so here comes a choice you need to make who is your end target audience and how will they listen

    the 80's had people using ghetto blasters to mix on ??
    The classical boys don't care and just make the best most truthful recording they can.
    The Rock boys want their CD's louder than the opposition.
    The Jazz boys ... well they just do their own thing ... always.

    Ok Kev, I'll assume you're being humorous here. :wink:

    IMHO, one should assume you'll have all kinds of listeners, on all kinds of systems. Yes, there are genres that determine the overall sound you're going for, but even small computer systems have additional bass (Subs) speakers, etc. nowadays, so it's best to just make sure it's a good mix overall. You should have the bass you want IF there a subwoofer present, but not so overdone to the point where it ruins the mix on a small or non-sub system.

    As for "The Classical Boys" - it's no different than a pop or rock approach for accuracy and bass where needed. (I assure you that a good pipe organ recording needs as much - or more - bass than anything else out there, same with a concert bass drum or a 6-bass orchestral section.) Ditto with Jazz - there's not a serious Jazz engineer working today that doesn't stress accuracy and max available power when it comes to mixing a trio or a hot jamming session.

    I'm sure you're having a little fun here, but regardless of the genre, the same rules still apply. Good accurate sound is the same goal for every engineer. There's no mystery here; truthful monitors are the goal, regardless of the music being played on them.
  11. Kev

    Kev Well-Known Member

    Nov 13, 2001
    fun yes
    but I disagree

    some clients are now asking for genre specific stuff

    pipe organ may have a strong bottom end BUT some dance is way hot
    Jazz singers may want accuracy so how does that fit with a squashed Green Day or Offspring vocal sound.
    Then there is the music being written for specific mediums
    NON CD audio mediums.
    ... net streaming , games and oh help us ... ring tones !!

    one size does not fit all

    I was asked to make sound sound scape stuff that did not sit on my acurate monitors at all well.
    Ended up final mixing on the theatre system for that specific show.
    SO much stuff below 40 hz my system just couldn't. I had to hire in low end gear and omit my normal low end. that's my PA system I'm talking about ... not my control room.
    This was back in the days of tape where I had a little more low end that on ProTools.
    The very lowest stuff was live out of signal generators and an analog synth.

    Just thinking about that show sends me back into shivers ... :shock:

    YES I am having some fun but there is a serious undertone here.

    The ghetto blaster was used to final check some 80's mixes.
    Unfortunately if the client asks for it ... they get it.
  12. Cucco

    Cucco Distinguished Member

    Mar 8, 2004
    Fredericksburg, VA
    Kev and Joe -

    I think you guys are approaching the same subject from different directions.

    Kev - what you're referring to in your most recent post is the sound that they're after during the recording process

    Joe - what you're talking about is how it sounds coming out of the speakers.

    In this case, I would kind of agree with both of you. Jazzers, Classical-ites, Rockers and all others (if they're serious about music) all want good/accurate loudspeakers. They may not understand what this truly means, but they still want it. This is why Bose is still in business - people *think* they're accurate.

    Of course, Kev, you're absolutely right - certain genres prefer to have their sounds recorded differently - more compression, less compression, more bass, linear bass and so on.

    Now, back to the monitors -

    Rasputin -

    Sorry to tell you - The Dynaudios still don't have enough bass energy to accurately monitor the lowest octave. I use the BM15s now quite religiously and for anything uber-critical (particularly classical stuff) I switch in my REL subwoofer to give me the tones between 5Hz and 35 Hz. This also frees up some of the wasted energy from the Dyns and the Hafler amp. (When I cross over the Dyns, I use a 12 dB/octave low cut starting at 50 Hz. These speakers sound amazing in that range and do just fine below it, but the REL is designed for these frequencies).

    And I do agree with Joe - fix the mix as much as possible before going to the ME. It's not the ME's job to remove plosives or footfall - it's the RE's job.

    Now, back on subject again -

    Remember one fundamental rule of physics -

    Sound, by definition, is air molecules moving in a specific manner to produce pitch, timbre, and amplitude.

    Hence, if a cone during play has an excursion of roughly 2 inches in and out (or 4 inches of total travel) than a crap load of air is being moved. The bigger the woofer in this case, the lower the frequency possible. (of course, only if excursion distance and cone linearity or rigidity is a constant).

    When you don't hear anything but you magically see your cone pop out and back then you have a fast transient acting in the lower frequency and the likely scenario is that the sound was a brief impulse at best and since the wave is too long to actually strike your ear directly (though you will obviously have air molecules in motion and thus *some* sound at the ear), it would rely on "filling up the room" or using the box that is your room to assist in reigning in that particular frequency so that the energy does not dissipate too quickly or even worse, resonate at prime or sympathetic frequencies.

    If the woofer, however, is providing even front to rear excursion continually, it is in fact producing a tone. If it is a continuous excursion but you can't hear it, this doesn't mean it's infrasonic - it just simply means that the energy is minimal - so much so that it dissipates before it reaches you at a detectable level. (Remember, energy cannot be created nor destroyed - the dissipation is often in the form of heat - not enough to change room temperature, but it's there. B/C remember from physics - kinetic energy of air, or for that matter any molecules, most often transforms into heat energy. Example - try bending a paper clip over and over at the same point very quickly. Then touch the clip to the top of your lip, just below the nose (a very temperature sensitive area). You'll notice the heat generated by molecules in motion.)

    If your room is technically accurate (i.e., no excessive modes or nulls) and you're speakers have the physical properties necessary to create lower frequencies, any *regular and even* cone movement will be quite audible.

    As Kev states - no, speakers do not generally go all the way down as most people think. Think of the way a speaker works (slightly simplified)-

    You have a magnet structure and a voice coil - a charge is passed to the voice coil which is suspended in the center of a hole in the magnet. As such, the voice coil - attached to the cone uses the principal of "opposites attract and likes repel" So, by passing a charge identical to that of the magnet, the voice coil is forced out of the magnetic field. Once it is cleared of the magnetic field, it begins it's return trip back to its resting place. (B/C again, remember rules of physics here - all actions have an equal and opposite reaction - hence, if there is a 2 inch excursion, there will be 2 inches of rearward travel beyond the cone's natural resting point - which consequently helps to make a nicely formated wave. Of course, usually another charge is passed to the voice coil interrupting its return voyage - and since energy can't be destroyed, the return trip (a physical requirement) heat is generated. The faster this happens (IOW, the higher the frequency) the greater the cooling requirement on the driver because more energy is converted more quickly.

    So, in other words - once the cone has reached the point where the voice coil has cleared the magnet, it has reached it's greatest excursion point (under natural conditions - there is the possibility of excessive momentum from an incredibly loud impulse) and therefore, the cone will only vibrate/move so much air. So, these are the natural limitations of a driver's low frequency.

    Now, let's imagine you have a 4" voice coil on a 5" woofer. The potential for a total of 8 inches of travel on a woofer without that much surface area would be disastrous. The cone could not remain rigid (or if it were made of a material capable of remaining rigid under this circumstance, you would find out very quickly that you have yourself a little "Voice Coil Missile") and thus the pure sound that has been passed to it is now broken up (distorted). This will destroy a speaker.

    So - long story (err, very long story) short - if you're watching your woofers and seeing a lot of activity - it's not infrasonic and it ain't something you "can't hear." It is in fact sound and it is in fact in the audible register. (Unless you have a pair of monitors with 15" or 18" monitors and they're flopping around like mad.) The difference is, your monitors may not be able to produce the air movement energy necessary to make the sound "loud" OR your room is zapping the sound altogether. (Usually a pretty good combination of both.)

    The simple solution is to mix with a true full range system comprised of components that are designed to reproduce their respective frequencies. Mini-monitors are perfect for stuff above say 50 to 80 Hz b/c their woofers/midranges/tweeters are designed for that (as are their cabinets - you don't want to imagine 8 inches of 12" cone travel in a 2.5 cubic foot box -- That's the definition of a ***BOOM*** box.) Subwoofers do bass and that's it. Good ones (and well-calibrated ones) do it well, others just plain suck. Be careful in your sub selection.

    So, when in doubt, use a sub. If you can't - trust what you hear, not what you see. Oh, and BTW - a continuous 30 Hz tone will make your woofer move quicker than you think it will - think about it - 30 cycles per second. If you see your woofer slowly rocking in and out - you might wanna check your connections or your power line - you've got some serious issues and your speaker is potentially in danger.

    I hope this helps and doesn't confuse...

  13. JoeH

    JoeH Distinguished Member

    Jun 22, 2004
    Philadelphia, PA/ Greenville, DE
    Home Page:
    Well said, Jeremy!

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