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Parametric Eq and low end

Discussion in 'Effects [BG]' started by ticol07, Jan 27, 2014.

  1. ticol07

    ticol07

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    Hello,

    I'm not sure if this subject is in the good thread since it's more an eq subject than an effect subject. So feel free to tell me if I'm in the wrong place.

    Here I am : I'm looking for advices to improve my low end tone especially live.
    I read a lot of threads regarding eq tips and since I have a parametric eq on my Zoom B3, I play with it a lot.

    What I understood is that what can create bad low end is a muddy tone and/or a too boomy sound.
    I read the tricks of using a parametric eq to find the frequencies that were culprit of this kind of problems. And then cut them a bit.

    So I choose a very narrow Q and swept the frequency between the ultra lows up to mids, with a big boost.

    And I hear 2 weird frequencies : 120Hz and 160Hz.
    If I boost them, I have a very bad ringing tone.

    They seem to be what many identified as the mud one (120Hz) and the Boom one (160Hz).

    For those who apply this kind of eq to clear their low end, do you sometimes point 2 frequencies too ?

    I'm already trying to raise or tilt my amp to have a better hearing of my tone on stage and already created a thread to talk about this. So, if possible I'd like the answer to be focused on the eq part of the low end :smug:

    Sorry if it's not clear, I do my best :)
  2. David Beers

    David Beers

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    In my opinion, the "mud zone" is more in the 180-250 hz range, right in the low mids. I almost always like to cut here, and if I want to boost the bass, I do so in the 50-90hz range. I also think it's good to roll off tones below 37hz or so, because you don't hear that and it just stresses out the speaker. Some power amps have this feature, but you should probably check out the micro-thumpinator from SFX.

    That said, trust you ears. You're doing the right thing by sweeping with a narrow peak to find the weird frequencies, and of course every bass and rig is different. :)
  3. ga_edwards

    ga_edwards

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    What you have likely found are room nodes. Resonant notes defined by the dimensions of the room your playing the the wavelength of certain notes. You may find that in a different environment the mud and boom frequencies you identified will change.

    Whilst it's always best to treat nodes acoustically by treating the space your playing in or moving your speaker can, this isn't always possible. A lot of us play in venues with small stages where you don't have the luxury of space, and in venues that are less than satisfactory in terms of acoustics.

    As such, I have added a Zoom MS-60B to my board mainly for its parametric eq for this very reason. Armed with this and a Gramma Pad, I fear no dodgy venue!
  4. David Beers

    David Beers

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    ^^^ that's also a great point, in addition to each bass and rig being different, each room is certainly another variable. Something you should do if you haven't already is experiment with where in the room you place your rig, as mentioned above. :)
  5. ticol07

    ticol07

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    Thanks for the replies.

    In the Zoom B3, there's a high pass filter which can but set from zero up to 200 Hz (the same is in the MS-60b : the AcBsPre which a copy of is the Fisherman Preamp). So I think there's no need to add a Thumpinator. It acts as a high pass filter too but with a fix frequency, no ?
    And yes, sometimes I use it. It can clean well some low frequencies.

    I think too that the weird frequencies I found are linked to the room. So I know the frequencies I found will not be exactly the same next time I move. But TWO weird frequencies : is it common ?
    And as you I often play in bad acoustic places. this is why I am investigating on all the good solutions to have the best tone and hearing it well.

    But I didn't thought of changing the place of the amp. I mean I try to not set it in a corner or against a wall, but I never moved it to listen the impact on the sound. Interesting !!

    And maybe I didn't tell the things the right way : when I talk about low end I think I'm looking to improve the low mids part of my tone. You know, the punchy lows.
  6. pbasswil

    pbasswil

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    So many aspects to this subject! Here are a few:

    1) Any time you boost a narrow freq. range, you will make certain harmonics stick out unnaturally.
    (In case you're not familiar with notes having fundamentals and then a series of overtones/harmonics piled on top, it'd be good to look it up.)
    Rule of thumb: if you must boost, do it with a medium or wide Q, and do it moderately.

    Btw: your "mud" and "boom" freq's are particular to your equipment and room, they're not universal in anyway -- except in the sense that too much of any freq will be annoying.

    2) Sometimes, weird tones that stick out when you boost are a result of poor quality EQ.
    One example: On the B3, if you use Graphic EQ, boosting the low mids sounds _bad_ (imho). The Para effect is better, smoother.

    3) Like someone mentioned, rooms almost always have certain frequencies that stick out -- at varying degrees of obviousness and annoyance! Boost there, and you're exciting the resonances so they stick out more.
    Also, instruments and speakers/cabs themselves have their own tonal idiosyncrasies, which can get exaggerated by the wrong EQ.

    4) Standard, simple EQ on basses and amps are not necessarily usefully configured!

    For instance:
    They all have Low shelving, which has its greatest effect at the nominal freq. elbow -- often 45hz, give or take 10hz.
    Being shelving, it also effects all freqs below that point; but also reaches up into the low mids to a lesser degree.

    The problem is: if you feel you want a little more "oomph" to your sound -- "oomph" being what I call the lows that you feel in your gut but can still hear -- what you often really want is an octave or so above that ~45hz.

    But you reach for the lows cuz that's all you have, and end up boosting all around that point, which turns everything to mud, and makes hollow objects shake, etc. etc.

    And at high volume, boosting low shelving will quickly challenge the limits of your amplification and speaker driver.

    I feel that the correct solution to getting a solid kicking bottom is a parametric band EQ (i.e., not shelving).
    I always start with a medium Q (width), and try around 100hz first. Then I adjust up and down to see what's best.

    But if you're getting boom or mud just above there, then by all means gently scoop it out until you're happy.

    It's amazing the volume you can get out of even a small speaker, if your EQ allows you to go easy on the sub freqs, while still have solid 100hz.
  7. David Beers

    David Beers

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    Particularly agree with this ^^^ :)
  8. ticol07

    ticol07

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    Thanks for the long explanation !

    I agree with regarding the paramatric eq vs the 7 band eq. I didn't find the use of the 7 band : you can't select precise frequencies and the bandwidths are very narrow.

    I wish the para eq as one more band. 2 is cool, 3 would be better. This is why I usually couple it with some preamp on my B3, to have more control on the tone.
    And since I think I understand well my eq from let's say 400 Hz up to the upper register, its lowest part is less intuitive for me.

    I like the principle of boosting some low mids with a bell curve (vs shelving). I always tried to do my best with the low control, but as you say it may boost to much sub frequencies, and this is why even if I hear more lows I don't feel my tone become stronger.
    I'll give it a try !

    In fact, I like simple things and was convinced that I could find a very simple way to shelve my low end. I mean, bass amps are supposed to be well designed !!
    But, the more and more I feel like the amps eq designs try to reach 2 goals which don't always work well together : the hability to sculpt your tone for real playing, and in the same time reaching good tones when you play alone.
    Usually when you try an amp before bying it, you try it without other musicians, so most of the people want to hear at that moment a good tone. But this tone will not be usable with bandmates...

    Ultimately, I think I'd like something like the AcBsPre on the Zoom products (the Fisherman copy) with a high mids sweepable frequency -> a High pass filter combined to a multi frequencies parametric eq. The perfect tone maker :)

    And what I don't understand is why parametric eq are not so common in a stompbox shape. It's so a powerfull tool !!
  9. jking138

    jking138

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    Probably because of the cost I would imagine.
    The AcsBsPre is brilliant, setting the depth to roll off the low end and the 40hz slider for any additional adjustments. I use the sweepable mid for a boost at 200 or 250hz to fatten my Jazz up, the next is set at about 1.5khz great for clarity and then the 5khz and 10khz as you prefer.
    I also use one of the amp sims with its mids set to 800hz to dial in some mids that the sim takes out, your graphs were extremely helpful in understanding amp tone shaping on the B3. They all share a similar shape, along with the sansamp and MXR sims, although I do prefer my actual MXR M80.
  10. ga_edwards

    ga_edwards

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    Yes, it does and can happen, especially if the room rectangular.

    Different frequencies have different wavelengths. The wavelength of low frequencies can be a few feet, whereas high frequencies can be measure in fractions of an inch (which is why guitarists don't have the same problems).

    If the dimensions of a room correlate with a certain wavelength, it will reflect the wave and either accentuate it, or diminish it, making it jump out or disappear.

    Thus, if you have perpendicular walls of different lengths, two frequencies could be affected.

    As mentioned before, moving the speaker can alleviate the problem. Move it in relation to the reflective wall and the wavelength won't reflect in the same way anymore, however, take care, as it could affect a different frequency instead! Sometimes, angling the speaker cab diagonally in a room so that is doesn't directly face a wall can help, or tilt it to point upwards slightly.

    Otherwise, you can acoustically treat reflective surfaces with soft furnishings and drapes to make surfaces less reflective. Or as you have discovered, the quick dirty way is to eq.

    Another thing to watch out for is hollow stages. The floor can resonate in sympathy with certain bass frequencies too, causing stage rumble and boom (stage acts like an acoustic guitar soundbox), this can sometimes creep up the mic stands and cause low end feedback too. I've started using a 'Gramma' isolation pad to alleviate this. In these problems venues, it really is quite wonderful. Nice tight and focussed low end without the mud!
  11. pbasswil

    pbasswil

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    It was fun to spout off. :^)

    Well that is indeed the nature of a graphic EQ (they're also quicker to adjust); but what I was referring to was the _quality_ of that particular effect on the B3. Some of the bands sound particularly artificial when boosted.

    You'd like 9 parametric bands in total -- Yikes, when would you have time to play bass?! :^>
    I guess it depends on if you need another effect taking one of the 3 slots, leaving 2 Para effects, = 4 bands.

    Well if you're determined to notch out every anomaly of the room, then the more bands the merrier, I guess; but you may have better and quicker results by moving yourself and your gear around the room a bit -- I would experiment with that first.

    As far as sculpting your tone (apart from resonances), I usually find 3 or 4 EQ bands are plenty, if they're the right ones.

    EQ has a strong psychological component, doesn't it?! Our ears and tastes are very influenced by context. Freq's that sound harsh or odd in isolation may actually help your tone in a band context.

    The biggest adjustment to playing in a group is usually mids-to-high-mids -- you simply need more to compete with guitars/keys/vocals.
    With experience, you learn to expect this, and plan for it even before the others start playing.

    Another lesson: Your bandmates all hear your tone differently, from their different perspectives on stage.

    More brain stuff: Your highs and mids effect your perception of your lows. If you don't have enough higher definition on your tone, it can sound like there's too much boom. Vice-versa: if you have a lot of highs and mids, you may not realize how much boom you're making -- whereas other people may find you boomy from a greater distance.

    Like above, add mids/high mids.

    Another strategy: if you have a Pre/Post switch on your D.I. Out, try to send the mixing board a Pre-EQ signal, and keep your EQ for your amp. A good sound man knows what your tone needs to blend into a front-of-house mix; let him do his thing, and you do your thing on stage. Your amp sounds _way_ different than the PA.

    Agreed! Empress makes a good quality one (although not as flexible as the B3).

    Btw, I've been gigging for 30+ years, and I feel like I'm only now learning to manage my tone. (Also, equipment is better today.)
    Keep on experimenting!
  12. ticol07

    ticol07

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    I made these graphs at first to teach myself :)
    Make a link between visual and audio is more simple for my simple brain !!
    And I guess it helps to understand the different cab tones.

    I didn't know the square / rectangular room effect. It makes a lot of sense. And moving its amp is more simple than cutting sepcific frequencies. Good trick !
    For the hollow stages, I already had figured that out (even if long years ago I was convinced that the more bass the more cool tone you had).

    I'm playing bass since more than 20 years and I don't know why it took me so long time to understand that I could achieve way better tones by understanding the eq subtilities.
    I guess the first years I was only focused on how to play the tunes without missing notes, then I was convinced that great tone was only very rich people with thousand dollars rigs. Next step was to see that bassists could have a perfect tone with a very simple rig when some others highly equiped could sound horrible.
    And then it's just a few years that I'm in the process of achieving the tone I'd like to hear. I know it's possible !!

    Mids and high mids : this part is OK for me. I can now set the things as I want (cut through the mix or being more in submarine mode).
    The only thing I miss (for my personal liking) is to calibrate well the low end : having the power without annoying everyone.

    And I understand well it's a matter of perception, which is more difficult to manage.

    I noticed another brainy thing. Don't know if it's the same for everyone : when I listen to me while playing I hear one kind of sound. If I record me on a looper, stays at the same place and listen to the loop, played on my rig, I hear a tone which is more defined and loud.
    Almost like if when you play you have the same kind of effect that occurs to a singer when he sings and can't hear well how he sounds in the speakers.
    Hum... if I'm alone in this case, don't tell it to anyone :bag:

    And I think there is some accomodation of the ears to a tone. If you play some tunes with a very thin tone, a small bass boost seems to be boomy immediatly and vice versa.

    Anyway, I think I begin to understand a lot of things with your answers.
    I'll try them on my next gig next week.
  13. ticol07

    ticol07

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    Hello, I could finally test all your good advices on rehearsal a few hours ago.
    Our rehearsal place is not good sounding so it's a good place to make some tone improvements (most of the walls are big windows, without curtains, so not really efficient to trap the sound !!).

    With my para eq I found the good low frequency to boost a bit to make my sound thicker without mud and without boom (in that precise case I had to boost a little at 150Hz). Sound was perfect.
    And I celarly heard the differences between the :
    - too low frequencies which brought some bass but not a lot af power
    - the mud/boom frequencies (in that room, in the 100/120 Hz area : so tipically the bass knob of my amp or the bass knob of the VT Bass I tried desperatly to use with no good results on the low end)
    - the good frequency (for my ears) at 150 Hz

    So, without para eq there wasn't simple issues to my problem.

    I'll try that trick on my next gig. I bet it'll work well !!
  14. Ladida67

    Ladida67

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    Hello,

    I think the Zoom B3 is available as a package with the Unzoom D69 at a Christian shop in Kansas City, Missouri. I FINALLY found it there, I just couldn't produce the sound I wanted before that.
    If any of you guys want any advice on how to plug it, feel free to ask, I'd be happy to answer your questions!
    by the way, hello Charlie C!

    Regards

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