I Don't Understand Markbass EQ

Discussion in 'Amps and Cabs [BG]' started by socknroll1, Dec 2, 2022.

  1. socknroll1


    Jun 20, 2011
    I will try to make this more of an observation than a complaint. Also, I just read part of a very long thread about how there really is no "flat" when it comes to amps, and I agree in concept, but so be it, part of my observation involves "flat".

    I bought a gently-used Markbass Mini CMD 121P IV, the later edition with mute button. Here is what confused me:
    • To my ears, with all EQ settings at 12 noon, it sounds like the mids are turned way up.
    • Fair enough. There is a switch for mid-cut. However, per the manual, this switch does a lot more than cut mids. It also boosts a lot of lows and highs. Flipping this switch really over-compensated from the first bullet point, so it wasn't useful, at least without a lot of other knob-turning. Read on...
    • There 4 EQ knobs. That is usually plenty, but the frequency of the high/treble knob really puzzled me. Most amps have the high/treble centered somewhere between 2KHz and 6KHz, a sweet spot to my ears for a little "bite" in the tone. The Markbass high knob is centered at 10KHz, the highest I saw in any manual. This seems too high. Turn it up a few clicks and the instrument sounds the same, only I'm hearing more string/finger noise. Crank it and I've finally got some bite, but the tone is irritating, clicky and thin.
    • The 3rd knob (mid-high) is centered at 800Hz, so there is a quite a range missing between 800Hz and 10KHz.
    I'm not usually so picky with amps. Generally leave most knobs flat, maybe boost a little between 1K-3K for "bite", and do everything else with the instrument's tone knob(s), so this is the first amp where I really struggled to get a good (to my ears) tone. I tried several rounds of "bedroom tone" and a few gigs. I ended up selling the amp after only a few months.

    Similar experiences?
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  2. I went through two Markbass heads in some months also, but not because of the EQ. I found that I could get a fairly wide range of good and useful sounds from them and I enjoyed the overall character. The problem I had was their threshold for low impedance...my 4 Ohm cabinet that wasn't going anywhere would trip protection at gig volumes.

    I don't think the point to be taken from the other thread is that "there really is no flat when it comes to amps", IMO, it's that flat (meaning something like "equal levels of frequency content from each band") doesn't mean the same thing as uncolored, which is the absence of individually defining character, where two amps that are truly uncolored should sound more or less the same. So, with regard to amps we use, it's probably more meaningful and fruitful to concentrate on what sounds pleasant to us rather than trying to find flat, especially while assuming that flat EQ on various amps strikes everyone the same way or makes them sound identical.

    One way you can look at it is that EQ band boost/cuts are like food seasonings. Just as you could potentially find an amount and balance of salt, black pepper, red pepper and garlic that strikes you as "flat", meaning that no seasoning stands out and in that balance and amount, the combination simply complements the food it's on. That doesn't mean that same combination of seasonings makes everything taste the same...it wouldn't make beef, chicken and fish indistinguishable. Each of those things have many other aspects that give them characteristic flavor.

    In that this has been an odd occurrence for you from the rest of your experiences, there's not much to say other that you didn't care for the sound of the Markbass CMD 121. Or, if you want to chase it down, maybe for you and from your observations, it'd be a good idea to consider amps that have some level of parametric eq. But also, while I agree it's a good idea to try to gain an understanding of the impact of various changes at different specific frequencies, I think that focusing on certain numerical aspects makes it very easy to fall into all kinds of thinking traps that seem logical.

    For instance, focusing on the numerical difference between 800 and 10,000 (where, "Wow! 9,200 is a lot of hertz!") skews the magnitude of difference that we're looking at in the aspect that's more relevant...it doesn't include the logarithmic nature of aspects of sound. In this case a difference of 9,200 Hz is a smaller magnitude change in pitch than the next lower 750 Hz difference...50 to 800 is 4 octaves while 800 to 10,000 Hz is 3.6 octaves. That and not really taking into account how wide the adjustment range is makes it easy to visualizing a gaping frequency hole that isn't really accurate.

    So, while it may not work for you, I don't think it's the obvious design flaw you might feel you've uncovered by looking at numbers. The EQ is as it was designed and it works for many other people.
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  3. Gearhead17

    Gearhead17 Supporting Member

    May 4, 2006
    Mount Prospect, IL
    OP, Nearly the exact same experience for me too! I have never liked the Markbass EQ. As far as hearing the mids jacked up immediately, perhaps your past amp heads had more of a scooped tone to begin with?

    I always found the 2khz zone on the Markbass heads to sound very strange compared to any other amp head. It was strangely hollow sounding there. My solution? Don't buy a Markbass head. Mesa D800 is my friend for life
  4. But does it go to eleven?
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  5. mellobud


    May 17, 2007
    I have two eq sections that are footswitchable. I usually have both on though. My complaint is that the ultra low is super boomy and I usually have to dial it back. The parametric is super helpful in dialing in my mids though.

    E3B048F4-ADBF-49EA-864F-DCAF0A89764A.png 322C5FD7-0A8E-4A3E-9774-D215ABF40E39.jpeg
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  6. socknroll1


    Jun 20, 2011
    Thanks for the replies. DrPepper, thank you in particular for the thoughtful reply. You're totally right that I was pointing out some numbers without fully understanding the scope, but I still find it strange that no other amp even approaches 10KHz as the center frequency on a treble knob, and my ears told me it sounded strange. Case in point - mellobud posted a Markbass head he likes. The High is centered at 3.8KHz. I have an idea of what that knob would sound like, and it's a lot more usable than 10KHz. But to be clear, I wouldn't say it's a design flaw, just an unusual design that didn't work for me. I learned that I should always read manuals/spec sheets first.

    As for going to eleven, I hope to never have the need.
    Gearhead17, drpepper and JRA like this.
  7. mellobud


    May 17, 2007
    That parametric eq on mine does go up to 12.
  8. agedhorse

    agedhorse Supporting Member Commercial User

    Feb 12, 2006
    Davis, CA (USA)
    Development Engineer-Mesa Boogie, Development Engineer-Genzler (pedals), Product Support-Genz Benz
    The problem is because you don't understand what the specs actually mean and not the specs themselves.

    The high eq is a shelving filter, and what the spec is actually indicating is the point of maximum boost/cut. Since it's a 6dB/octave slope, and say it's +16dB at 10kHz, it's also +10dB at 5kHz and +4dB at 2.5kHz. Most shelving controls operate this way, but how they are specified can be the difference. Also, since how far from the knee is not specified, there's no way to know if they are taking the -3dB point from +16dB or +20dB. This lack of clarity is common to this type of filter (Baxandall shelving).

    In reality, there's nothing wrong with the eq points IMO.
  9. Very nit picky, but two things...first, I understand you, but the adjustment frequencies for bass and treble tend to be shelving type, not centers. For treble, the adjustment the the higher side doesn't strictly have a slope set by the control; all frequencies beyond that point are boosted or cut. The upper rolloff can be dictated by a separate filter or inherent limitations. And again, the slope matters...it's not an immediate cutoff at 10 KHz, if it's 2 octaves, it's effects are reaching down pretty far.

    Secondly, no other amp that you're aware of has 10 KHz as the fixed treble shelving. I'm pretty sure that there are other amps that use 10 KHz, possibly higher. I had an Eich, and it's not the kind of thing that just pops up in a search without digging a bit, but if I'm remembering correctly, it was 10k or more.
    Al Kraft, socknroll1 and agedhorse like this.
  10. DanAdams


    Nov 3, 2013
    Whenever anyone mentions confusing controls, I can only think of this...
    Last edited: Dec 2, 2022
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  11. Bassamatic

    Bassamatic keepin' the beat since the 60's

    Please be aware that the 121P FILTERS (VLE and VPF) are at 50% when at 12 o'clock position. OFF is at full CCW
    MrKpawz, Gruff, gypsyfelon and 5 others like this.
  12. socknroll1


    Jun 20, 2011
    Hey, that's exactly why I come to TalkBass - learning from experts! Thanks.

    As for VLE and VPF this model was updated and does not have those anymore. Instead, it's a switch for the mid-cut I mentioned above, and an "old school" knob, which I left all the way off (0 or 7pm) for my tone-testing.
    Al Kraft and SJan3 like this.
  13. Gormsgade


    Jun 17, 2005
    The very well respected Glockenklang Bass Art Classic pre-amp is designed with
    +/- 15 dB at 12 kHz, so don`t think it`s that unusual.
    Al Kraft, SJan3 and AlexanderB like this.
  14. Bassamatic

    Bassamatic keepin' the beat since the 60's

    I think that the "Old School" filter is the same as the VPF was. Anyway, be sure that it is full CCW for your testing
  15. I don’t own a Markbass and I can never remember what those filters do when I encounter one. Hopefully I’ll remember they are off at full CCW.
  16. VLE and VPF are what I mainly use , the combo of the 2 gets me almost anything I want , mostly I use the scooped mid of the VLE ?? or is it VFP !! lol gotta look at the amp , ok VPF
    SJan3 likes this.
  17. non


    Aug 4, 2015
    my practice amp has the treble at 10 khz. it sounds great using a speaker without a tweeter or a speaker that you can turn the tweeter off.
  18. Zbysek


    Mar 23, 2017
    Czech Republic
    VPF is mids scoop, VLE is low pass filter…
    mcnach, ahbradot, SJan3 and 1 other person like this.
  19. SJan3

    SJan3 Supporting Member

    Dec 8, 2010
    He's talking about a LittleMark IV head. There is no VPF filter. Only the VLE renamed Ol Skool filter which by the way will calm the 10k that some of you are so sensitive about.
  20. SJan3

    SJan3 Supporting Member

    Dec 8, 2010
    No. It's the VLE renamed.
    mcnach likes this.