High Pass Filter (HPF) and Low Pass Filter (LPF) Mega Thread

[Stumbo]

I just realized that my live wireless system transmitter (Sennheiser Freeport) has a frequency response of 60Hz-16Khz ± 3 dB.
Does anyone knows what exactly happens with the freqs. out of this range?
Thanks

So, you have a wireless HPF? Cool.

 

[Downunderwonder]

So, you have a wireless HPF? Cool.

More likely the 3dB response dropoff point.

 

[agedhorse]

Generally wireless system rolloff is 6dB/oct but there are exceptions such as some AT models.

 

[Stumbo]

Generally wireless system rolloff is 6dB/oct but there are exceptions such as some AT models.

So most wireless users have a default HPF built-in that's always on? Wow. That'll be news to a lot of wireless users.

 

[loopee]

really? All Wireless units?

 

[PraiseBassing]

So most wireless users have a default HPF built-in that's always on? Wow. That'll be news to a lot of wireless users.

really? All Wireless units?

Not all. Digital units usually have a wider frequency range.

 

[dabis]

Line 6 states on theirs a freq. response of 10Hz-22KHz. Don't know the
± x dB.
I only read the manual of my unit (Sennheiser freeport) that it's a guitar oriented, others maybe are wider.

 

[Stumbo]

HPF's and down-tuning?
HPF/LPF list- which do you use or know about?
Ampeg PF500 EQ and HPF
In praise of the HPF
Geez, now I'm all freaked out cuz I don't have a HPF
best 15" or bigger cab(s) to add for big clean low end?
Bass frequency/waterfall plots: what they mean to rigs and HPF/LPFs

 

[basst scho]

i´ve read a few times that a hpf can give you more headroom (that i really need, when playing with the band) and thighter low end

can i get that benefit from a hpf, even if i use compression on the low frequencies anyway?

the only pedal i can find in my part of the world is a hotone skyline gate, which is a noisegate (would be also really handy with my bad technique) with lo-cut and hi-cut filters.

[Invalid or Expired Link Removed]

you guys think this is worth a try?

 

[adje]

i´ve read a few times that a hpf can give you more headroom (that i really need, when playing with the band) and thighter low end

can i get that benefit from a hpf, even if i use compression on the low frequencies anyway?

the only pedal i can find in my part of the world is a hotone skyline gate, which is a noisegate (would be also really handy with my bad technique) with lo-cut and hi-cut filters.

[Invalid or Expired Link Removed]

you guys think this is worth a try?

The VONG filter is local to you, but it's a DIY kit - all you need is the stuff you need to do some soldering.
VONG-Filterung – Schalltechnik_04

 

[Old Garage-Bander]

Generally wireless system rolloff is 6dB/oct but there are exceptions such as some AT models.

So, in general, not as effective as some of the true HPFs that roll off at 12db/oct or more?

 

[JimmyM]

So most wireless users have a default HPF built-in that's always on? Wow. That'll be news to a lot of wireless users.

Not all. Digital wirelesses usually have more down low. Honestly, though, I was always fine with the analog wirelesses that had 60 hz as the -3db point. Probably because I always used cabs that did, too

 

[NKBassman]

i´ve read a few times that a hpf can give you more headroom (that i really need, when playing with the band) and thighter low end

can i get that benefit from a hpf, even if i use compression on the low frequencies anyway?

Of course. All that low frequency content is still there, just now it’s being compressed.

If you like your compressed sound the way it is, then put the HPF after the compressor and you still get the benefit of filtering out mud before the amp.

If you put the HPF before your compressor you’ll probably notice a difference in how the comp reacts to the signal. Low frequency mud can trigger the compressor to clamp down harder on the incoming signal than it should, so if you filter out the lowest lows before the compressor you’ll get a much more natural reaction to the actual peak of the note.

 

[NKBassman]

The thing with the wiresless system cutoff at 60 Hz is a good example of how high pass filtering can be used to optimize a system.

I don’t know anything about the ins and outs of wireless units per se, but the system designer will have made a choice to set the cutoff that high in order to optimize the system to work more efficiently, and not waste energy transmitting <60Hz content that won’t be heard from a guitar rig anyway.

This is exactly what we are doing when you put your HPF pedal in front of your amp. You are filtering out “useless” frequencies so that your amp and cab can work more efficiently with the remaining signal.

 

[agedhorse]

Not all. Digital units usually have a wider frequency range.

Generally true, but many digital wireless systems also have programmable HPF features too.

So, in general, not as effective as some of the true HPFs that roll off at 12db/oct or more?

Correct.

Of course. All that low frequency content is still there, just now it’s being compressed.

If you like your compressed sound the way it is, then put the HPF after the compressor and you still get the benefit of filtering out mud before the amp.

If you put the HPF before your compressor you’ll probably notice a difference in how the comp reacts to the signal. Low frequency mud can trigger the compressor to clamp down harder on the incoming signal than it should, so if you filter out the lowest lows before the compressor you’ll get a much more natural reaction to the actual peak of the note.

The problem with keying the compressor's action on the very low or subsonic signals is that it can artificially squash the entire signal based on an out of band signal's control. It it an unnatural action that usually doesn't sound (or feel) very good. Some comp manufacturers high pass the key (or side chain) signal for this reason.

 

[scottfeldstein]

The problem with keying the compressor's action on the very low or subsonic signals is that it can artificially squash the entire signal based on an out of band signal's control. It it an unnatural action that usually doesn't sound (or feel) very good. Some comp manufacturers high pass the key (or side chain) signal for this reason.

Hm. So maybe I put the HPF before my comp. I'm liking "beginning of the chain" more and more. In theory. I guess I'll see when mine arrives.

 

[RoadRanger]

Hm. So maybe I put the HPF before my comp. I'm liking "beginning of the chain" more and more. In theory. I guess I'll see when mine arrives.

The Fdeck series 1 is first off a high impedance pickup preamp so with my passives always goes first anyways.

 

[basst scho]

The VONG filter is local to you, but it's a DIY kit - all you need is the stuff you need to do some soldering.
VONG-Filterung – Schalltechnik_04

Of course. All that low frequency content is still there, just now it’s being compressed.

If you like your compressed sound the way it is, then put the HPF after the compressor and you still get the benefit of filtering out mud before the amp.

If you put the HPF before your compressor you’ll probably notice a difference in how the comp reacts to the signal. Low frequency mud can trigger the compressor to clamp down harder on the incoming signal than it should, so if you filter out the lowest lows before the compressor you’ll get a much more natural reaction to the actual peak of the note.

thx guys. yeah, another 60 bucks gone , sounds like i need one...

i´ll try the hotone, soldering is not one of my strenghs. at least it wasn´t 20 years ago, when i had to solder in school...

 

[GrapeBass]

Hm. So maybe I put the HPF before my comp. I'm liking "beginning of the chain" more and more. In theory. I guess I'll see when mine arrives.

I think the point is that the compressor, like the Broughton APEX, is the proper way to go. I also believe the HPF/LPF should go last in the chain except for spacial effects such as chorus or verb.

 

[agedhorse]

I think the point is that the compressor, like the Broughton APEX, is the proper way to go. I also believe the HPF/LPF should go last in the chain except for spacial effects such as chorus or verb.

Why would you think this? Can you give us some rationale for your recommendation?