HPF + HPF

sears

sears

Supporting Member
Aug 7, 2005
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#1
What about running HPFs in series? I play a 4-string P. A PLX with its 30Hz filter engaged through a couple of Acmes. Sometimes people tell me they can't hear ME. I do get compliments on my "thick" sound but some people can't hear it.

What if I ran an HPF at 40Hz before the preamp? (an Ashly SC40 with a low shelf.) Or even another frequency depending on how it sounded right then and there? That (presumably higher-pitched) HPF would necessarily happen before the built-in filter in the power amp.

Does anybody do what I'm talking about, or would two HPFs be redundant, or would you want to run the higher HPF last anyway and my plan is backwards?
 
#2
Maybe I'm not getting something here, but why would you be running a bass, which is primarily lows, thru one, let alone two high pass filters? It's my understanding that high pass filters only let the highs pass thru. Running thru two would only allow a very high end and tinny sound to be heard, sort of negating the use of the bass as a low-end provider.

I use a high pass filter for an occasional special effect to remove all lows, but can't see my main bass sound coming from a pair of them. You sure you don't mean low pass filters?
 
#3
I think it may be redundant to have one at 30 and another at 40. The one at 40 would filter everything below it anyway.
As far as being heard, i dont really have any advice to offer, but i see lots of folks say that mids add definition, and helps a player be heard.
 
#4
Usually, if you employ an HPF to tighten up your low end, you want to use a very steep High pass filter, to better retain your low freqs above the cutoff frequency. If the Ashly is a low SHELF filter, it's probably not the optimal choice for what you seek.

Look into an fDeck or Broughton HPF. both are steep, adjustable, and you would only need the one filter.
 
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#5
MGR said:
Maybe I'm not getting something here, but why would you be running a bass, which is primarily lows, thru one, let alone two high pass filters? It's my understanding that high pass filters only let the highs pass thru. Running thru two would only allow a very high end and tinny sound to be heard, sort of negating the use of the bass as a low-end provider.

I use a high pass filter for an occasional special effect to remove all lows, but can't see my main bass sound coming from a pair of them. You sure you don't mean low pass filters?
Click to expand...
Have you never heard a bass in a room that sounded too boomy for its own good?
 
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#6
sears said:
What about running HPFs in series? I play a 4-string P. A PLX with its 30Hz filter engaged through a couple of Acmes. Sometimes people tell me they can't hear ME. I do get compliments on my "thick" sound but some people can't hear it.

What if I ran an HPF at 40Hz before the preamp? (an Ashly SC40 with a low shelf.) Or even another frequency depending on how it sounded right then and there? That (presumably higher-pitched) HPF would necessarily happen before the built-in filter in the power amp.

Does anybody do what I'm talking about, or would two HPFs be redundant, or would you want to run the higher HPF last anyway and my plan is backwards?
Click to expand...
Both the Fdeck 3 HPF preamp/pedal and the new Mesa Subway D-800+ amp basically do that - a fixed frequency lower frequency HPF coupled with a variable frequency HPF. You'll be fine - try it and see :) .
 
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#8
Got to agree with RoadRanger, the HPF-Pre Series 3 is excellent for what the OP wants help with. It has a fixed filter at 12dB /octave set at 35HZ and a second 12/dB/octave filter that is adjustable from 35-140HZ. It is outstanding for tightening up bass in a booming venue and/or preserving headroom by eliminating amplification of frequencies that aren't useful/usable.

Mesa D-800+ and other bass amps have similar features included. In many cases they are much more effective than traditional EQ controls in my experience.
 
#10
guy n. cognito said:
Beyond the hpf, what does the rest of your eq look like?
Click to expand...
In my case the EQ is usually close to flat/neutral unless I have some areas where I'm finding a problem and then my approach is to try cutting first. I own a number of amps and cabs so I tend to select the combination that is voiced for what I'm going for and don't need to use a lot of EQ.

More often than not I end up dropping some treble/high end and if I boost, it's usually low mids.
 
#11
Al Kraft said:
In my case the EQ is usually close to flat/neutral unless I have some areas where I'm finding a problem and then my approach is to try cutting first. I own a number of amps and cabs so I tend to select the combination that is voiced for what I'm going for and don't need to use a lot of EQ.

More often than not I end up dropping some treble/high end and if I boost, it's usually low mids.
Click to expand...

I'm sorry, that was a question for the OP
 
#12
MGR said:
Maybe I'm not getting something here, but why would you be running a bass, which is primarily lows, thru one, let alone two high pass filters? It's my understanding that high pass filters only let the highs pass thru. Running thru two would only allow a very high end and tinny sound to be heard, sort of negating the use of the bass as a low-end provider.

I use a high pass filter for an occasional special effect to remove all lows, but can't see my main bass sound coming from a pair of them. You sure you don't mean low pass filters?
Click to expand...
30hz and below isn't really adding much to your tone. I used to run my Hpf at about 60hz to clean it up.
 
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#15
2 hpf's in the 30 to 40 hz range won't make that much of a difference. Isn't it more likely you are boosting the 40 to 80 hz range to much? If you have the EQ options: maybe try to boost a bump somewhere in the 80 to 160 hz range. There's more to the bass range than 40 hz
 
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#16
MGR said:
Maybe I'm not getting something here, but why would you be running a bass, which is primarily lows, thru one, let alone two high pass filters? It's my understanding that high pass filters only let the highs pass thru. Running thru two would only allow a very high end and tinny sound to be heard, sort of negating the use of the bass as a low-end provider.

I use a high pass filter for an occasional special effect to remove all lows, but can't see my main bass sound coming from a pair of them. You sure you don't mean low pass filters?
Click to expand...


A high pass filter is used to remove sub frequencies, either because of the way the room is reacting to them (creating "mud") or because they causing over-excursion problems in the cab you're using (making the cab "fart out").

A very common practice when mixing rock music is to set a very steep HPF somewhere between 40Hz and 60Hz, your ears only really hear the 1st harmonic overtone from notes that low anyway :thumbsup:
 
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#17
sears said:
What about running HPFs in series? I play a 4-string P. A PLX with its 30Hz filter engaged through a couple of Acmes. Sometimes people tell me they can't hear ME. I do get compliments on my "thick" sound but some people can't hear it.

What if I ran an HPF at 40Hz before the preamp? (an Ashly SC40 with a low shelf.) Or even another frequency depending on how it sounded right then and there? That (presumably higher-pitched) HPF would necessarily happen before the built-in filter in the power amp.

Does anybody do what I'm talking about, or would two HPFs be redundant, or would you want to run the higher HPF last anyway and my plan is backwards?
Click to expand...

A single steep HPF set at 30Hz likely isn't doing much unless you've boosted the bass shelf a lot or are playing a lot of VERY low notes; even the fundamental of the low B on a 5 string is ~31Hz.

A others have mentioned, look into something like an FDeck: it does a great job of cleaning up the bottom end and eliminating cab or room issues.
 
#20
guy n. cognito said:
Beyond the hpf, what does the rest of your eq look like?
Click to expand...

Well, it's pretty flat except I'm using the low shelf as much as it can go, different frequencies. Probably at 40 when I'm outdoors and higher in some indoor places. I'm not very scientific. I think I sound pretty good and I do get compliments but the people who can't hear me tend to be non-musicians and I want very much to please them.
 
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