• TalkBass has been independent since 1998. Add your voice.
    Create a free account to reply to discussions, view embedded media, and browse with fewer display ads.
    Join free Log in
    Want zero display ads or expanded classifieds tools? Compare plans.

Why basses don't come with a HP filter in the electronics?

#41
Munjibunga said:
Why not just get any active preamp that has boost/cut bass (which would be most of them) and cut some bass? Pope preamps even give you a choice of frequencies at the bass end - all bands actually.
Click to expand...
Typical on-board bass preamps control a range that is centered on a certain frequency; the width of the range controlled is usually referred to as the "Q".

For example, the common 31 band equalizer used in pro audio racks is also often refered to as a "1/3 octave equalizer" because each slider controls a range of frequencies that is 1/3 of an octave wide, centered on the frequency specified for that slider, i.e. each slider has a Q of 1/3. When you raise the slider marked "100Hz", you're actually adjusting everything between roughly 85Hz and 130Hz, with a little "peak" at 100Hz.

In your example, the bass control might be centered at 30Hz or 40Hz, but it's controlling frequencies on both sides of that center frequency. Usually, the fewer knobs you have, the wider the Q is. A three band EQ will have a fairly wide Q just so you can have fairly smooth, full control over your entire audible frequency range. With a 31 band EQ, each "knob" can control a much smaller slice of the range, and so they can each have a fairly narrow Q.


So, bottom line is, the bass control in a typical oboard preamp is going to affect frequencies well up into what most of us consider the meat and/or potatoes of our tone. Turn it down and you will lose all your booty, and you may find yourself being identified as a "guitarist".

High pass filters are designed to attenuate all frequencies below a specified point - they basically have a "Q" that is infinitely wide on the bass side of the cutoff frequency.
 
Last edited:
#42
I don't know why, but it is rare to see any manufacturer include "Q" in the equalizer specifications of most equipment, even though it plays a large part in how an equalizer behaves.. There's a few things that have the Q as a standard part of the device name (1/3 octave, 2/3 octave, parametric = adjustable center and Q), but outside of those devices, it's a rarely seen specification.
 
#43
As far as the original question - why don't basses come with onboard high pass filters?

Because high passing at 30Hz or 40Hz takes some of the thickness out of your tone. How much is debateable (of course), but 30Hz is the fundamental frequency of a low B string, so many players are going to be reluctant to cut in that frequency range.

Also, electric basses don't really generate subharmonics on their own, so the only problem frequencies you'll encounter are generally going to be caused by issues that could be remedied by more careful/improved technique - "thump" from fingers coming to a hard rest on the string below the one plucked is a major contributor. There is a device called a "Thumpinator" designed to help with this exact thing, and I've heard plenty of players that say they're very effective.

With an acoustic bass, there's a good chance that the body of the bass will pick up vibrations from the floor and the drum kit; also, it's very common for these basses to use a piezo pickup. The combination of attaching a vibration-sensitive pickup (aka "piezo") to a large hollow structure that is probably coupled to a hollow stage, which has people walking around on it, and also has somebody beating on large hollow objects (aka "drummer") which are also coupled to the same hollow stage......... is a perfect design for picking up rumble......... so subharmonics are a genuine problem for acoustic upright bass, and a lot of these players have found a HPF to be very useful.
 
#45
SanDiegoHarry said:
Okay, so explain to the audience of what utility might a HPF be on a bass guitar?
Click to expand...
I have an amp that IIRC is flat (+/-3db) down to 20Hz. My cab unloads below 35Hz so anything lower than 35Hz is wasting power (and headroom as already stated) and likely to damage my driver.

Palm muting my strings produced a large visible jump of my driver cone. Adding a 35Hz HPF with a steep roll off (24db/octave) eliminated the cone excursion and made no difference to the sound. Win/win situation for me but as always YMMV dependent upon the design of your equipment.
 
#46
delta7fred said:
I have an amp that IIRC is flat (+/-3db) down to 20Hz. My cab unloads below 35Hz so anything lower than 35Hz is wasting power (and headroom as already stated) and likely to damage my driver.

Palm muting my strings produced a large visible jump of my driver cone. Adding a 35Hz HPF with a steep roll off (24db/octave) eliminated the cone excursion and made no difference to the sound. Win/win situation for me but as always YMMV dependent upon the design of your equipment.
Click to expand...

Very good. Thanks.
 
#47
BruceWane said:
Typical on-board bass preamps control a range that is centered on a certain frequency; the width of the range controlled is usually referred to as the "Q".

For example, the common 31 band equalizer used in pro audio racks is also often refered to as a "1/3 octave equalizer" because each slider controls a range of frequencies that is 1/3 of an octave wide, centered on the frequency specified for that slider, i.e. each slider has a Q of 1/3. When you raise the slider marked "100Hz", you're actually adjusting everything between roughly 85Hz and 130Hz, with a little "peak" at 100Hz.

In your example, the bass control might be centered at 30Hz or 40Hz, but it's controlling frequencies on both sides of that center frequency. Usually, the fewer knobs you have, the wider the Q is. A three band EQ will have a fairly wide Q just so you can have fairly smooth, full control over your entire audible frequency range. With a 31 band EQ, each "knob" can control a much smaller slice of the range, and so they can each have a fairly narrow Q.


So, bottom line is, the bass control in a typical oboard preamp is going to affect frequencies well up into what most of us consider the meat and/or potatoes of our tone. Turn it down and you will lose all your booty, and you may find yourself being identified as a "guitarist".

High pass filters are designed to attenuate all frequencies below a specified point - they basically have a "Q" that is infinitely wide on the bass side of the cutoff frequency.
Click to expand...
Thanks - I'm very familiar with full parametric EQ.
 
#48
BruceWane said:
So, bottom line is, the bass control in a typical oboard preamp is going to affect frequencies well up into what most of us consider the meat and/or potatoes of our tone. Turn it down and you will lose all your booty, and you may find yourself being identified as a "guitarist".
Click to expand...

It all depends on why you want the LPF. The Bass VI instruments have a LPF precisely so you can sound like a guitarist. Many active basses have a "shelving" filter for the bass and treble bands and they intentionally affect frequencies that we are interested in, that is the whole point of having the onboard preamp. You can't color your tone with filters that only affect inaudible frequencies. For example the preamp found in many Fender active basses does this:

FenderPreampChart1.jpg


And the tone controls on many amps do basically the same thing. If the OP wants this kind of filter in his bass then he already has it in his active preamp or his stage amp or perhaps even an external preamp.

If he wants a super steep sub-sonic filter to protect his speakers or whatever then an onboard preamp isn't going to cut it and rather than add more active stages which suck current to get one, why not just put it into the amp which gets all the power it wants from the wall outlet? Besides it is the amplifier's job to protect the speakers, the bass's job is to smoke those puppies!
 
#49
I'll often put Fdeck's HPF pedal just after my bass in the signal chain, on a high-volume gig. It stops anything below below 35 Hz (like sloppy palm muting, as mentioned above, or--in my case--overly aggressive dead thumps on the low strings) from moving along to the compressor or amp. Those freqs are not musically useful to me (on a 5 string in standard tuning), but they can trigger the compressor or burden the amp. These are points raised above, in the thread.

To the OP, I'd just as soon do the high-passing (i.e., remove the subby non-musical content of the signal) after the bass. I don't feel a big need to do this in the bass itself.

The microthumpinator is another high pass pedal. OP, it may be helpful to pull up the TB threads on those boxes to get the idea of what they're used for.

A good point KJung raised on the Fdeck HPF thread is that some amps roll off the sub range, and other don't. So how much you need a HPF filter depends on the amp.

Again, it's definitely worth the time to peruse the threads on HPF filters to get a feel for when they're most beneficial.
 
Last edited:
#50
Ewo said:
To the OP, I'd just as soon do the high-passing (i.e., remove the subby non-musical content of the signal) after the bass. I don't feel a big need to do this in the bass itself.
Click to expand...

Same here, but I could see it being useful for others. I prefer it just in front of the power amp in many cases, but as usual, just depends. Not all subby content is necessarily non-musical either, IMHO.
 
Last edited:
#53
delta7fred said:
The 3 band Musicman preamp does have a HPF built in, can't remember the cut off frequency but IIRC it is 12db/octave, admittedly it is not as steep as the Fdeck but better than nothing.
Click to expand...

walterw said:
wait, it has a rolloff at 60Hz? is that independent of the actual bass EQ knob? where does said knob boost typically?
Click to expand...

Passinwind said:
Walter, my model isn't optimized for MM pickups at all, so I wouldn't put any great stock in it beyond that there is indeed a 2nd order HPF. That 60Hz figure (-3dB point, cut actually starts well above that) is with the bass control at noon, which appears to be the nominal flat position. Looks like the bass control boosts with a peak at 70Hz, taking interaction with the HPF into account, but cuts from an octave or so higher up. I haven't built one of these yet, but I definitely want to eventually.
Click to expand...

Does anybody know whether the on-board high pass filter was installed in Sterling MM bass made in nineties?
 
#56
On the original question: HPF could easily be integrated into an active bass design, on a passive not so much. Two problems doing it on a passive: 1) Too gradual slope. 6 Db per octave would suck out much of the low end as well as the problem sub-frequencies. 2) Pickups are inductive components. Add a capacitor, or another capacitor as the tone control already uses one, creates an LC tuned circuit which resonates at a specific frequency, that frequency will either be sucked out or boosted. That effect is sometimes used, and useful on guitars, on bass not much.
 
  • Like
Reactions: JfetPre775
#57
Lorenzop said:
Hi all

I'm a electronics noob but:

1) Why basses always lack a HP filter (say integrated with the tone knob, active or passive) - when instead a mix Engeneer reaches for a HP asap when mixing bass?

Ok in mix context is different BUT wouldn't a HP filter in tone control, maybe set at the lowest fundamental of bass (4 or 5 string) or indeed a sweepable HP make ALOT of sense, as first in signal chain thus removing crap out of bass before hitting pedals, preamps, compressors and power amps?


2) Second question, is a HP filter difficoult to build? As an inboard HP? Wouldn't it be possible to put in an active bass electronic? Or even passive for that matter?

A lot of good, even hi-end active bass preamps (Jreteo, Glockenklang, Eden etc etc) offer a lot of good tone filters but why none has a switch for HP filter???
Click to expand...

-Easy answer; They’ve been equipped on electric guitars & basses since well.. guitars and basses have existed. But even though they’re still standard fare for passive instrument’s, nobody actually REALLY utilizes or likes them especially..
*Okay I’m being a bit facetious including “everyone” in that statement. Even so I’d still wager that a poll would show the majority (95% plus) gtr/bassist’s never touch the tone pot, keeping it wide open permanently.
Traditional country guitarists who play bright voiced Fender and Vox amps dead clean alongside ice-pick brittle Tele/Esquire bridge pickups.. Are one instance where a cap bleeding highs to ground is welcome.

-Second, In an active 2/3/4 band Bass Eq; the treble pot moved counterclockwise from center cuts high frequencies in a very specific, controlled, arguably more musical way. Most circuit designers and musicians feel this is a more than adequate (often superior) way to deal with excessive highs.

-The answer to your question about whether it’s difficult and/or prohibitively expensive to incorporate a passive tone control into a design; The answer is no not really.. It will increase overall cost somewhat. But mainly it just depends on what most customers want & if your circuit will still be sized within spec. Generally speaking the smaller the circuit is the easier it will be to install, customize, and fit the multitude of different of basses without needing to permanently route or modify an instrument..
 

Latest posts

Top Bottom
Back