High Pass Filters

[peteb]

4 minutes ago, stewblack said:

Thread revival. 

20 pages way too much to plough through. 

Quick question: how, given the HPF removes inaudible frequencies, do you tell if it's working?

 

If you're amp is working a little more efficiently and you are not getting issues with low frequencies in larger rooms with dodgy acoustics. 

 

[krispn]

You could observe the speaker cone movement if you can take the grill/cover off the cab too. 

[Maude]

6 minutes ago, stewblack said:

Thread revival. 

20 pages way too much to plough through. 

Quick question: how, given the HPF removes inaudible frequencies, do you tell if it's working?

Look at your speakers. 

 

You can usually set the cut off level higher and you can hear the bottom end rumble disappear. 

But when it's set to just lose the inaudible rumble you can honestly see the speakers move less. 

I use an FDeck with doublebass through my PJB Suitcase and without the FDeck my little speakers were pumping back and forwards, switch the FDeck on and the sound is the same but my speakers are barely moving. 

Therefore my amp is getting a huge rest as well not having to produce all that power to move those speakers. 

I also find that the entire band sounds cleaner as a result of there being less subsonics in the room. 

 

[Stub Mandrel]

16 minutes ago, stewblack said:

Thread revival. 

20 pages way too much to plough through. 

Quick question: how, given the HPF removes inaudible frequencies, do you tell if it's working?

 

You stop seeing the cone move when you handle the bass or hit a string.

[PaulWarning]

funnily enough, I was messing around with the 30 Hz slider on my Trace Elliot GP12 today, couldn't tell any difference whether it was right down or half way, so I left it right down

[JPJ]

I’ve ended up with two on my board. The first, always on and completely unadjustable Micro Thumpinator, just does what it’s supposed to do and protects whatever amp/speaker combination I have down stream from mechanical damage due to over excursion. The second, is switchable and on the bloody marvellous Sushiboxfx Finally ‘with bass in mind edition’ v2 valve DI. This seems to have a much steeper slope and you can really feel/hear the difference when it’s switched on. Great for those problematic booming stages, but I find best left off at most venues as the Micro Thumpinator is doing its thing and I already have the HPF enabled on the desk. 

[stewblack]

Thanks guys.

[Baloney Balderdash]

14 minutes ago, JPJ said:

I’ve ended up with two on my board. The first, always on and completely unadjustable Micro Thumpinator, just does what it’s supposed to do and protects whatever amp/speaker combination I have down stream from mechanical damage due to over excursion. The second, is switchable and on the bloody marvellous Sushiboxfx Finally ‘with bass in mind edition’ v2 valve DI. This seems to have a much steeper slope and you can really feel/hear the difference when it’s switched on. Great for those problematic booming stages, but I find best left off at most venues as the Micro Thumpinator is doing its thing and I already have the HPF enabled on the desk. 

It is not steeper, it's just that cut off frequency is higher on the Sushiboxfx.

[Baloney Balderdash]

12 hours ago, stewblack said:

Thread revival. 

20 pages way too much to plough through. 

Quick question: how, given the HPF removes inaudible frequencies, do you tell if it's working?

Depending on where the HPF cutoff frequency is set and how steep the curve is it can also audible tighten up the low end, making it less floppy and boomy, and a bit more punchy, and well, tight, sounding.

 

Edited July 22 by Baloney Balderdash

[Dood]

9 hours ago, PaulWarning said:

funnily enough, I was messing around with the 30 Hz slider on my Trace Elliot GP12 today, couldn't tell any difference whether it was right down or half way, so I left it right down

 

I was sure I rememebr reading a Trace Elliot manual that said as much many years ago (which is interesting as I have never owned a TE 12 band)

I have found it on page 8 of a TE manual for the 12 band range:-

 

"Do not use excessive bottom ( 30 to 40Hz ) boost on the graphic unless your speakers can handle it. Very few speaker systems are capable of handling frequencies as low as 30 and 40Hz with any degree of efficiency.

N.B. Boosting at 30Hz for instance will not add to the perceived amount of bottom end in the sound, it will only make your speakers flap to no useful effect. In fact boosting at 100Hz or 180Hz will have the apparent effect of adding far more bottom end than boosting at 30, 40 or even 60Hz.

Do not use excessive top ( 10 to 15kHz ) boost, this will add mostly hiss to the sound as there is very little signal output at this frequency from a bass.

The 30Hz slider has been provided to allow precise tailoring at very low frequencies. This

slider should be used to CUT ( not Boost ) the 30Hz to a level that allows the speaker system to

work at its maximum efficiency."

 

 

[paul_5]

8 hours ago, Dood said:

 

I was sure I rememebr reading a Trace Elliot manual that said as much many years ago (which is interesting as I have never owned a TE 12 band)

I have found it on page 8 of a TE manual for the 12 band range:-

 

"Do not use excessive bottom ( 30 to 40Hz ) boost on the graphic unless your speakers can handle it. Very few speaker systems are capable of handling frequencies as low as 30 and 40Hz with any degree of efficiency.

N.B. Boosting at 30Hz for instance will not add to the perceived amount of bottom end in the sound, it will only make your speakers flap to no useful effect. In fact boosting at 100Hz or 180Hz will have the apparent effect of adding far more bottom end than boosting at 30, 40 or even 60Hz.

Do not use excessive top ( 10 to 15kHz ) boost, this will add mostly hiss to the sound as there is very little signal output at this frequency from a bass.

The 30Hz slider has been provided to allow precise tailoring at very low frequencies. This

slider should be used to CUT ( not Boost ) the 30Hz to a level that allows the speaker system to

work at its maximum efficiency."

 

 

I seem to remember the 30Hz slider having a red cap instead of the standard white one - this is why.

[PaulWarning]

4 minutes ago, paul_5 said:

I seem to remember the 30Hz slider having a red cap instead of the standard white one - this is why.

it does indeed

[Lfalex v1.1]

I would tend to use HPFs and amp eqs to protect drivers/amps and clean up the on stage/ rehearsal sound. 

 

If I have to use the onboard DI, it'll be pre-EQ if possible.

 

I favour outboard preamps for instrument tone manipulation,  and it's their DI I'd rather send to the desk. 

[SuperSeagull]

12 hours ago, Baloney Balderdash said:

Depending on where the HPF cutoff frequency is set and how steep the curve is it can also audible tighten up the low end, making it less floppy and boomy, and a bit more punchy, and well, tight, sounding.

 

Exactly how I describe mine working. 

[Downunderwonder]

On 22/07/2024 at 08:33, stewblack said:

Thread revival. 

20 pages way too much to plough through. 

Quick question: how, given the HPF removes inaudible frequencies, do you tell if it's working?

Play about raising the HPF until it sounds like it is missing something. Back it off until it isn't. It's working.

 

You should find that the bass control on the amp now behaves a little differently. You can bring it up with no ill effect instead of causing speaker to flap. It may be that an extra bit of HPF can work with significant bass boost to tailor a much more full low end.

[Frank Blank]

Just now, Downunderwonder said:

Play about raising the HPF until it sounds like it is missing something. Back it off until it isn't. It's working.

☝☝☝ this exactly. It's a difficult to define effect but I have set mine in exactly the way described above and everything just sounds tighter, as if the speaker is working more efficiently, which of course it is.

[msb]

A surprising number of modern amps have built in high and low pass filters. 

[Al Krow]

Agree with all the comments about the benefit of HPF's to eliminate low end crud to improve speaker efficiency, particularly in the subsonic range (<20Hz) and equally also below the low B fundamental at 31Hz (or 41Hz for the low E for 4 string basses).

 

My key learning point, with very helpful input from fellow BC'er @ratman, who is both a pro bass player and a capable sound engineer, and who kindly came along to one of our gigs recently, is to think of the business end of the bass frequency range as being up to 200Hz.

 

Our analogue desk has a built in HPF with cut-off kicking in at 100Hz - engaging that for the bass left the sound feeling thin and lacking weight, so I've gone instead for a pedal setting at 50Hz with a 12dB/oct cut but then adding a 3dB boost at 140Hz in the "low mids". (Fwiw I've personally found it unhelpful to think of 120hz+ as "mids" because it's very much in the bass frequency range and mids go so much higher! Maybe time to reclaim this end of the spectrum as "bass", haha!)

Bingo, the bass is now 'back' adding that proverbial 'heft' that had been lacking.

 

So we are currently HPF'ing everything on the desk other than the bass and kick drum, and applying a separate HPF at 50Hz to just the bass.

Edited July 24 by Al Krow

[Chienmortbb]

9 minutes ago, Al Krow said:

I've gone instead for a pedal setting at 50Hz

I cannot agree more. The area below the fundamental is not musical at all and most of our sound comes from the 2nd harmonic upwards. A simple hearing test will prove this. If anyone can get to grips with WinISD, you can apply a filter ans see how little difference an HPF make to the response of the bass sound when modelling a cabinet/driver.

[Baloney Balderdash]

On 02/02/2018 at 17:47, Al Krow said:

Here's the Dood's excellent review of the (it's big brother) B1Xon. (Well done @dood btw - I hope GAK are paying you royalties?)

Takes up too much real estate on my little pedal board (MS-60B wins hands down for compactness) and I do prefer the user friendly interface on the B3n over this; but you're right the B1on is cheap and does do a lot.

The first comment in the YouTube comments section made me laugh! 

 

Also you can't assign any given parameter of any given effect in each patch to be controlled by the expression pedal, at any interval or direction on the B3n, as you can on the B1Xon.

 

They sure did make the B3n more "user friendly", if that is what you chose to call dumbing it down by removing, not only useable, but great features and flexibility.

 

In my opinion the B3n and every proceeding Zoom multi effect was a step back in the wrong direction.

 

The effects (bar the drive and amp/cab emulations, but then again they are also not great on the B3n) on the B1Xon even sound better (and again are more tweakable/flexible), despite using less processing power.

 

Edited July 24 by Baloney Balderdash

[Al Krow]

@Baloney Balderdash - impressed with you quoting a post of mine from 6 years back! I'll happily admit to not being the same BC'er I was back then! Maybe it is actually possible to grow wiser and not just older? 😅

[Baloney Balderdash]

10 minutes ago, Al Krow said:

@Baloney Balderdash - impressed with you quoting a post of mine from 6 years back! I'll happily admit to not being the same BC'er I was back then! Maybe it is actually possible to grow wiser and not just older? 😅

Well, good for you, genuinely. 

 

But I did not look at the date of the post, since this thread still seems very current (even if admittedly I did went off topic, but so did you).

 

Edited July 24 by Baloney Balderdash

[Stub Mandrel]

3 hours ago, Al Krow said:

Our analogue desk has a built in HPF with cut-off kicking in at 100Hz

 

A killer for keyboards, bass and some kick drums.

[Stub Mandrel]

My view (which may be a minority one) is that the troublesome frequencies from handling noise putting your palm on the strings etc. are effectively sub-audible, that is below 20 Hz where we hear them as a 'purr' or thump rather than a musical tone.

 

This is full octave below our E string and well below even a low B at 32 Hz, so a 12 or 18dB/octave filter at 30Hz will stop all the non-musical sounds like a wall with minimal effect on the fundamentals if our equipment is able to reproduce them.

 

Personally, I would only look at a higher frequency (say 50Hz) if I was using a speaker with limited high-end response or a lower power amplifier and I wanted the extra headroom.

[Al Krow]

10 hours ago, Stub Mandrel said:

 

A killer for keyboards, bass and some kick drums.

 

Our keys player is banned from using her left hand 😅

Edited July 25 by Al Krow