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

[Downunderwonder]

You need the hpf after any octave down.

 

[agedhorse]

You need the hpf after any octave down.

Correct, this will (probably) help the octave down circuit to track better.

 

[The Mouse]

I put the hpf+lpf just before the pre-amp. It's working well, tames all the madness. I did like it before the comp too but I think it's utilised better where it is now. Thanks for your help peoples, I appreciate it!

 

[Zbysek]

I put the hpf+lpf just before the pre-amp. It's working well, tames all the madness. I did like it before the comp too but I think it's utilised better where it is now. Thanks for your help peoples, I appreciate it!

My point was tu put (envelope) filters in front of compressor...

 

[dabis]

Results are here: 60 per cent of sound techs preferred to be sent pre HPF signal, 1.5 per cent preferred post HPF signal, 38.5 per cent did not care. 70 sound techs participated in the survey...

One thing I'm thinking about these preferences: with PA support, good subwoofers can go down to 25Hz -10dB (an exemple are L-Acoustics KS28, that can be seen here in Barcelona on the biggests festivals, large stages). If my bass is producing freqs. from 29 Hz and I'm cutting lows at 45Hz to protect my speakers, there's something in the subwoofers that I'm missing. Don't know if these frequencies are producing something nice or just vibrations to the venue. I'm refering anything between my lowest not (29Hz) and the HPF cut that I think as you teached us, safer for my equipment (45Hz).

Maybe the techs that prefer pre HPF signal it's because the bass is the best source of lows to move them subwoofers

 

[The Mouse]

My point was tu put (envelope) filters in front of compressor...

I tried that too. Think I prefer putting dirt before filters though.

 

[Downunderwonder]

Maybe the techs that prefer pre HPF signal it's because the bass is the best source of lows to move them subwoofers

or they want to make @JimmyM sound like a subwoofer.

 

[BadExample]

Sound guy could also just be better able to eq the signal and make the whole mix sound right.

Gigging with unknown sound guys at shaky venues might be an argument for a switchable and adjustable HPF

 

[Stumbo]

v

@Al Kraft:
Fdeck HPF PRE Series 3. I find a variable HPF can work miracles in acoustically difficult rooms and allows for interesting tone shaping options when you flip on a deep switch or crank some bass EQ with the HPF dialed up a bit.

Other than that, an Aguilar TH pedal, Tech 21 BDDI (especially the new V2), PDDI, VTBass, MXR M-80, or Xotic Bass RC Booster all have plenty of extra tone shaping ability for me.

 

[K-2]

Sorry guys for a stupid question, but searching for a answer to this specific question is quite hard . What is the difference between HPF and EQ. In my situation I have 3 bands of low I can adjust (head - Peavey minimega, preamp - tech21 dp3-x, Bass - Sire M2) . As far as I know Sire preamp can cut and boost @20 Hz, whic is pretty low and is the lowest Point of my EQ. Would shaping low end with head and preamp (as well as compressing low end) and then cutting lowest lows with Sires onboard preamp yield similar results to having an HPF? Or the EQ curve down low would be different from HPF?
Apologies for any English mistakes.
Cheers and thanks in advance!

 

[agedhorse]

A high pass filter is a shelving type of filter with the response flat above the selected cutoff frequency and the response falling at a specified slope (or rate) below the cutoff frequency (often 24dB/octave). With a typical bass eq, when you turn it down, it rolls off like a high pass filter to about -12dB and the slope is almost always 6dB/octave.

As you turn the eq control down, the cutoff frequency typically shifts up relative to flat response.

 

[Kukulkan61]

Pretty much every amp I have designed over the last 20 years includes at least a fixed HPF.

Depending on the intended application of the amp, it's typically somewhere in the high 20's Hz to low 30's Hz.

Does the D800 have a fixed HPF?
Thank you Sir..

 

[agedhorse]

Yes, approximately 30Hz, 4 pole.

 

[AaPee]

Here is my tone board.

 

[Stumbo]

v

@Darkglass:
I think that’s where our miscommunication happened: I can’t speak for what Dug used back in the day or Andrew at Tech21 to replicate it (huge respect to both guys by the way).

But the guitar distortion sound you described can be achieved with a bass signal with a HPF cutting a lot of low before a high gain stage.

 

[Craig4003]

After some months of use, I'm still really, really happy with my FDeck HPF v3. It's the perfect cure for the booms. I adjust it a bit one way or the other depending on the room situation and which bass I'm using. It amazes me that I played bass for 30+ years with no clue that I needed such a thing.

 

[Stumbo]

How fdeck's HPF came about and lots of great info on it: Review of new pre-amp/high-pass filter

 

[lowplaces]

Hosted an open mic last night and forgot my pedalboard. Now I realize how indispensable my Broughton HPF has become.

One of the regular guitarists that shows up ask to me if my amp needed new tubes LOL

 

[Dubsly]

I promised a gig report a while back, but was waiting until I played every type of gig I usually encounter. I have to say the HPF is a total game changer. From small strangely shapped bars to old converted churches with 30ft ceilings, or larger venues with raised usually boomy stages. I even went as far as to switch up to the Quilter 800 for my gigging amp, so I have the feature available if my pedal were to quit working.

 

[Stumbo]

I promised a gig report a while back, but was waiting until I played every type of gig I usually encounter. I have to say the HPF is a total game changer. From small strangely shaped bars to old converted churches with 30ft ceilings, or larger venues with raised usually boomy stages. I even went as far as to switch up to the Quilter 800 for my gigging amp, so I have the feature available if my pedal were to quit working.

Cool! Thanks for the gig report.

Which HPF and rig are you using?

Bass?