If my speaker is only rated to 45hz do I need a HPF to tighten up my B string?

Discussion in 'Amps and Cabs [BG]' started by Outbush, Sep 24, 2021.


  1. Outbush

    Outbush

    Nov 6, 2016
    Australia
    Sorry folks but I've looked and looked.

    The title says it all really. My B string sounds just fine through my headphones; nice really, like the E string but lower. Actually, the same applies when playing not plugged in at all. Once I'm playing through my rig the B string notes are not as defined. They are better at higher volumes than the low volumes I use messing about at home but still not as nice as through my headphones. To describe what I hear, it is almost to say I hear the multiple harmonics as clearly as any fundamental and that is quite different to what I hear when I play my A string. My A string just sounds like a single powerful note/frequency. I play through an EA Doubler with a Wizzy 10 stacked on a Wizzy M-Line (which is a 12" speaker) and EA say both my cabinets are very suitable for 5 strings and I am very happy with the rig, but I would love my B to sound as defined as my E and A strings.

    So if my speakers fail to produce much below 45hz (which is their minimum rating) is that a "natural" equivalent to a HPF?
    If I were to use a HPF set to 45hz would the rig respond any differently and would my B string be clearer?
    Would it be better to tune a HPF to just under 60hz to get the first (and subsequent) harmonics of the B string and add a bit of bass at the amplifier?
    Would that also improve my E string if the cabs aren't full generating the 40hz fundamental of E?

    To add to my confusion I have watched a few YouTubes where the B string sound reproduced with a HPF applied sounds worse to me than the intial take without HPF (and I don't want to spend $300 Aussie to find out a pedal would do the same).

    I have seen a few threads where the OP is confused by all this and yet seems to have done a bit of reading just like me so I am at your mercy. Plus, I'm sure there are others wondering the same... Ta!
     
  2. Wasnex

    Wasnex

    Dec 25, 2011
    The problem may be because you are mixing dissimilar designs.

    AFAIK the Wizzy 10 is a reflex cab and the M-line is a transmission line. If these cabs have drastically difference phase and group delay characteristics they may fight with each other, rather than summing perfectly.

    I suggest you try each cab by itself. You may get less volume and lows, but the sound may improve. Ideally you want a pair of identical cabs...or at least cabs that have compatible tunings.

    I do know that an HPF can help a reflex cab. All basic ported/reflex designs have sort of an "S" shaped excursion plot. Here is an example from the cab design document for the Eminence Deltalite 2512.

    upload_2021-9-24_4-5-36.png
    The 2512 is rated for 250RMS, but notice this particular design only has 125W of mechanical power handling below 100hz. Also it requires a steep HPF set to 35hz.

    Notice that excursion increases below about 500hz. Excursion peaks around 70hz and then starts to decrease. The reason is when the port starts becoming active it suppresses driver excursion. (Fb) port tuning is 44hz and Xmax is 4.9mm. Notice that excursion dips at 44hz and then picks up quickly as the frequency goes lower. The excursion line turns from black to gray at 35hz. This is where the driver hit's Xmax with 125W. With the HPF applied, the signal will be attenuated by 3dB at 35hz. A 3db change essentially means the power has been cut in half (125/2=62.5W), which keeps driver excursion below Xmax.

    Below Fb output of a ported design tends to drop off quickly. So excursion is increasing and response is decreasing.

    Here is the response plot for this design:
    upload_2021-9-24_4-15-46.png

    Notice how low the output is at 35hz compared to 100hz. Usable response is frequently defined as the point where output is down -10dB. The graphs shows almost 120dB at 100hz, but only about 105dB at 35hz. After you apply the 3dB cut for the HPF the response will be down to 102dB. So IMHO there is probably not really enough output at 35hz to be considered usable. AFAIK this is the raw response plot without the HPF applied. With the HPF, the low frequency cutoff will become steeper at 35hz.

    I don't know how EA rates the low frequency cutoff, but I would not be surprised if 45hz is the point where the cabs are down by -10dB.

    I do think an HPF would be good idea if you plan to push these cabs hard with heavy lows. In my experience, an HPF will tend to make the lows tighter and more clear/focused. These are qualities I like, but some prefer big pillow lows that are sort of loose and woolly. In some instances an HPF can also make it sound like there are more lows, but in my experience it tends to be very subtle.

    With the HPF, the driver is able to work better in it's intended pass band, because it is not flopping around like crazy trying to produce super low frequencies.

    Anyway you can try an HPF before you buy?
     
    mustbampeg, puff father, fig and 13 others like this.
  3. Outbush

    Outbush

    Nov 6, 2016
    Australia
    Thanks very much for the response - very clearly explained but I will still have to reread it a couple of times. :sorry:

    Sadly no, there are no bass shops for hundreds of kilometres really. A few music shops within a couple of hours drive but not that have this sort of specialised stuff so I'm really trying to get as much info as I can in advance of making a decision.
     
    DJ Bebop and Reedt2000 like this.
  4. el murdoque

    el murdoque

    Mar 10, 2013
    Germany
    In my experience,
    if you're after a tight low end and don't like muddy sound, a HPF will do wonders for you.
    Some units have HPF in place without advertising it too much, like the Sansamp pedals
    or some amp heads.
    I usually use a HPF unit with adjustable cutoff frequency and just set it to 'wide open', then
    turn it up while playing low.
    To my ears and with my gear, I can discern between unwanted mud and much wanted lows.
    I turn the knob until it starts cutting wanted lows, then back off a bit and I'm done.
     
    lomo, Ampslut, Zbysek and 7 others like this.
  5. Mushroo

    Mushroo Guest

    Apr 2, 2007
    Does cutting the Low EQ on your Doubler tighten up your B string?

    If the answer is "yes" then an adjustable HPF will allow you to cut low frequencies even more surgically and precisely.

    You could even do the classic boost/cut studio trick where you boost the Low EQ but then cut the low-lows with the HPF.
     
  6. beans-on-toast

    beans-on-toast

    Aug 7, 2008
    The speakers on paper is one thing. An important question is, how well does your amp actually reproduce 45Hz. Maybe it’s already rolling that off to some extent. A phone app spectrum analyzer can give you a rough picture of what’s going on.
     
    Outbush likes this.
  7. Lobster11

    Lobster11 Supporting Member Supporting Member

    Apr 22, 2006
    Williamsburg, VA
    In the meantime you can follow his suggestion to try each cabinet separately. If they each sound good alone, then the problem would seem to be simply that they don't get along well with each other and you need to replace one or the other. In that case no pedal will help.
     
    mikeswals, TomB, DJ Bebop and 3 others like this.
  8. Blues Bass 2

    Blues Bass 2 Supporting Member

    Oct 3, 2001
    Davenport Iowa
    What does the notch filter do on your amp ? I see it goes to 50Hz . Maybe this would do what you need. You could try it .
     
  9. micguy

    micguy

    May 17, 2011
    The curve posted above (to an Acoustical Engineer) says it all. If you play notes low on your bass, the speaker will move a lot, but not really put out much sound at the fundamental of the note. This is not something odd in your speaker - the desire for light and loud means that almost every commercially available bass guitar cabinet has this shortcoming.

    If you do play without a high pass filter (there is one in your amp, but it may not be enough), and play low notes at relatively high volume, the speaker's excursion (it's movement) will go past where it's "linear" - it goes past where it operates cleanly. At that point, it starts generating a bunch of harmonics. If you're playing a low E (41 Hz), it'll put out 82 Hz, 123Hz, etc. Those first two harmonics will sound OK, as will the 4x and 6x - they're "musical" overtones of the note you want to hear. But higher up - at 5x and especially at 7x the fundamental, you get into very non-musical territory. 7 times 41Hz is 287Hz, which is also in the area that we perceive as "mud" if there's too much. Contrary to popular belief, it's not the 41 Hz that's "mud", it's the non-musical overtones that result from driving the speaker too hard at low frequencies that is the "mud" that a high pass filter cleans up. If you ever get a chance to play through a clean, well set up (that's important) high powered PA with good subs, you can get a lot of 41Hz, and not have it sound at all muddy. It'll sound solid, and have a lot of impact.

    So, a high pass filter is the cure for mud, but not for the reason most folks around these parts think it is.
     
    T. Brookins, lomo, TomB and 7 others like this.
  10. burgerdj

    burgerdj

    Dec 4, 2006
    Maryland
    Using a HPF has been a game changer for me. Having a hard cut off of all frequencies below a selected frequency has been far more effective than simply cutting at a certain frequency. My little Walkabout combo works much more efficiently - and I still get all the low end I could possibly want (or use).
     
    Gearhead17 likes this.
  11. Jefenator

    Jefenator Supporting Member

    Aug 22, 2008
    Oregon
    HPF can be nice - I've used it mostly to tame the sometimes raging low end from the piezo pickups on upright basses.
    For the best articulation with a low B string on electric bass, the most helpful thing I've found is to use the bridge pickup (assuming the bass has one). Even the best low B axes I've tried benefit from at least some bridge blended in and even my weakest 5-string can growl out in that register when I solo that pickup. (Bit of an extreme measure for me - 100% bridge is not my thing normally.)
    HTH
     
  12. cassanova

    cassanova

    Sep 4, 2000
    Florida
    The HPF on my Mesa was a real game changer for me. It allowed me to cut out unwanted boominess and maintain clear, tight focused bottom end of the B string. In short, it helped make it sound less muddy, and more articulate, better than attenuating the bass frequency on the head.
     
    Jazzdogg likes this.
  13. pbassjbass

    pbassjbass

    Jun 21, 2013
    Maryland
    Might the problem be the room? In my practice room, I've resonance at around b flat (I'm using a four string).
     
  14. sawzalot

    sawzalot Supporting Member

    Oct 18, 2007
    The reality is that with our instruments most of what we hear is actually the 1st octave harmonic, not the fundamental. 40 hz is REALLY low and 30.87 hz is REALLY REALLY low. I set my HPF by ear, but I don't have any problem setting an HPF on a PA to somewhere in the 50-55 Hz range...there's just not that much content below that and it really frees up the amplifier watts to reproduce what actually IS there while simultaneously protecting against over-excursion of the drivers.
     
    Rip Van Dan and Phaidrus like this.
  15. Thumpin6string

    Thumpin6string Supporting Member

    Apr 25, 2013
    Shoals Indiana
    I always use an always on HPF for any head and for any cabinet. Besides cleaning up the lows, it helps keep your speakers safe. One of the best bass tools IMHO and even better with a compressor.
     
    Zbass82 likes this.
  16. jw23mind

    jw23mind

    Jan 16, 2017
    Reading MA
    It's not just whether you can hear the lows (due to speaker response), but that your amp is still trying to make them and thus eating up valuable headroom. Remove those sub lows with an HPF and there will be more "room" for the lows you want.
     
    Gearhead17 and puff father like this.
  17. makanudo

    makanudo

    Dec 26, 2008
    Amateur/enthusiast here, but from all the Mixing Bass videos I've seen and tried on my personal rig and recordings, HPF and compression are essential to a "profesional" sounding low end. You can turn the bass' volume higher without creating a mess in the room/mix and risk damaging speakers.

    I personally set a HPF at 72-80 Hz and boost bass if needed or move the HPF further down or up. Also from experience I would advice using a HPF on smaller and or lower powered combos/rigs to leave more headroom and squeeze a bit more performance out of the equipment.
     
  18. brianrost

    brianrost Gold Supporting Member

    Apr 26, 2000
    Boston, Taxachusetts
    Outbush,

    The original Doubler has a single adjustable HPF (a trimpot accessed from the top of the amp, frequency range not specified) and the later Doubler II head has one on each channel with a 3-way switch (25 hZ (factory setting), 50hZ or 80hZ). So no need to buy an external HPF just yet ;)

    Check the manual for details and experiment!
     
    Wasnex and Haroldo like this.
  19. JeezyMcNuggles

    JeezyMcNuggles Suspended Supporting Member

    Feb 23, 2018
    Santa Maria, CA
    I suck, but nobody really notices
    No, higher the frequency roll off, the tighter the low end will be.
     
  20. Phaidrus

    Phaidrus

    Oct 25, 2009
    Apologies in advance if my question is slightly off topic. My cab (a Markbass NY122) has a frequency response of 45Hz-20kHz. How does it manage to reproduce a low E at 41Hz? And would a cab rated, say, 35Hz-20kHz, be truer to what an open E string sounds like and hence sound better?

    PS. I asked this question a while ago in another forum but I'm not sure I understood the answer.
     
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