Jump to content
Left leaderboard
funkydoug

High Pass Filters

Recommended Posts

well that was interesting, tried the slapping over the pickup method @Jus Lukin suggested, once again the Zoom had little or no effect but turning down the 30Hz slider (-15db) on my Trace GP12 did, so maybe my zoom is a load of cack

Share this post


Link to post
Share on other sites

This lunchtime I've mostly been modelling HPF and LPF filter blocks in LTSpice... As you were...

Any feeling on LPF filter range? Looking at 700Hz - 14.5kHz at the minute.

Edited by Bigwan

Share this post


Link to post
Share on other sites
2 minutes ago, Bigwan said:

This lunchtime I've mostly been modelling HPF and LPF filter blocks in LTSpice... As you were...

Any feeling on LPF filter range? Looking at 700Hz - 14.5kHz at the minute.

Sounds like a pretty comprehensive range to me!

The Broughton goes from 330Hz to 20kHz, but frankly I'm not really sure I'd really ever want to cut below 3kHz so the ability to go down to 330Hz seems a bit redundant?

What do other folk think?

Share this post


Link to post
Share on other sites
3 minutes ago, Al Krow said:

Sounds like a pretty comprehensive range to me!

The Broughton goes from 330Hz to 20kHz, but frankly I'm not really sure I'd really ever want to cut below 3kHz so the ability to go down to 330Hz seems a bit redundant?

What do other folk think?

A wider range is easily achievable with a higher value of potentiometer, but this range is with same value as the HPF so only have to keep one value to hand.

Share this post


Link to post
Share on other sites

I think 14.5khz is as high as I can hear (13.5 in the left ear!) so that's good for me!

I think the VLE in Markbass pres goes down to 250hz, but it's hard to imagine much need below 700. We will still have our passive tone controls on board to do the really heavy lifting!

Share this post


Link to post
Share on other sites
4 hours ago, Bigwan said:

This lunchtime I've mostly been modelling HPF and LPF filter blocks in LTSpice... As you were...

Any feeling on LPF filter range? Looking at 700Hz - 14.5kHz at the minute.

Walter Harley (of cafe Walter) put a short article on his website detailing a variable low pass fiter he used about 2000. Unfortunately I cannot find any references to it now, but I still have a paper copy. It works from 200Hz to 20KHz,with a 12dB/octave slope,  but his stage gain was 1.16, which was considerably less than the 1.6 you would use for a Butterworth response, so the corner or knee of the graph is much smoother. I've built a couple and they sound good.

I've emailed him to see if there is still an electronic version of the original article available, but if anyone can trawl through historical web pages, they might ba able to find it;

Heading - Rackmount Bass preamp

Subheading - Walter Harley September 2000

Share this post


Link to post
Share on other sites

One(!) of the good things about this thread is that it's made me download the (free) Zoom GuitarLab software and add some of the various new effects they have for the B3n including this fabled 'LoEq' mentioned by a few of you earlier in the thread (and many thanks for spotting). All very straightforward and easy to use once I'd managed to filch an USB cable with the right connections for the B3n from our Amazon Fire TV box! 

Well the LoEq effect itself is a doddle to manipulate: choice between 'shelf' or 'HPF'; range from 20Hz to 640Hz and -12dB cut to a +12dB boost. I set up a patch with HPF/30Hz/-12dB and 2 of these LoEq effects in series to get the minimum recommended -24dB cut.

And there was me listing my B3n for a song a couple of weeks back, in a Dood-like quest for compactness, before realising the error of my ways - what was I thinking?!! (I've even managed to get a pretty good dirt patch using the SMR400 effect, which was a pleasant surprise, and could mean that one of my current digital dirt pedals is not long for it's stay on the Krow pedal board...)

Just need to work out somehow, how to persuade @bartelby to upgrade his B3 to a B3n so that we can get him to model some of this :) 

 

Edited by Al Krow

Share this post


Link to post
Share on other sites

When the LoEq effect is set to HPF the gain parameter has no effect. I assume this means that it is already a fixed cut at -24db so using 2 effects wouldn't be necessary. The gain parameter only works in Shelf mode.

Edited by Opticaleye

Share this post


Link to post
Share on other sites
On 2/5/2018 at 06:16, Bigwan said:

This lunchtime I've mostly been modelling HPF and LPF filter blocks in LTSpice... As you were...

Any feeling on LPF filter range? Looking at 700Hz - 14.5kHz at the minute.

At what slope?

 I once started in on a standalone variable HPF design, which I gave to a German friend to develop as he saw fit. That was years ago though, not sure if I can even remember who it was. All my DIY amp builds over the last few years have had one, but it has always been tightly integrated with all the pre-existing rolloffs of various other stages in the amps. LTSpice is great for modeling that sort of thing.

Edited by Passinwind

Share this post


Link to post
Share on other sites
4 hours ago, Opticaleye said:

When the LoEq effect is set to HPF the gain parameter has no effect. I assume this means that it is already a fixed cut at -24db so using 2 effects wouldn't be necessary. The gain parameter only works in Shelf mode.

Ah ok thanks for clarifying that. I would be surprised if a single Zoom effect managed to cut by more than 12dB though: 12dB seems to be the maximum cut with several of the EQ effect sims delivering individual cuts less than this from Bartelby's charts.  

Share this post


Link to post
Share on other sites
On ‎01‎/‎02‎/‎2018 at 20:49, Lozz196 said:

Havin read on this thread that the Rumble feature on the Tech 21 Para Driver v2 is a high pass filter I thought I`d give it a try this eve, and am pretty pleased with the result, albeit through my practice amp at home volumes. Engaged I have to push the bass on the PD a lot more, in fact to full on, plus back off on both the highs and mids a bit, add a bit more gain, and reduce the blend to 80% instead of full on in order to get the same sound as before.

So why do it then - well the sound is the same but seems more focused, and, being a heavy hitter the sound could boom a bit at times whereas now it doesn`t so I`m getting a more controlled version of my sound. I suppose it`s a bit like finally finding the compressor that actually does what I want it to really, keeping me as me, but also reigning me in a bit. I`ll update as to whether it works in the band or not next week, but am feeling pretty chuffed at the moment.

Update - tried it, didn`t like it, sounded too clean & cultured for me. In a 3 piece I need to fill out a lot of room, and trying this made the bass a lot clearer and focused, but removed a lot of the filling sound. ideal for recording, or in a band with 2 guitars, but not for my current band. I think I`m just too uncultured for this sophisticated sound stuff.

Share this post


Link to post
Share on other sites
4 hours ago, Lozz196 said:

... trying this made the bass a lot clearer and focused...

Sounds good to me Lozz! 

You thought about using an Orange rig with everything set on flat to get that completely yuk mush tone? I can't stand, but the corollary is that it's probably right up your street! :D

PS I should probably caveat my jibe by noting (in all seriousness) that the sound clips you've previously shared of you playing sound really very good.

Edited by Al Krow

Share this post


Link to post
Share on other sites
7 hours ago, Bigwan said:

-12dB/oct was my thinking 

I think that's a good call. If you haven't already, you might want to take a look at my (non commercial, completely free) open source onboard preamp design on Talkbass. I'd be happy to send you the LTSpice model to play around with, but the schematic is already available in the project WIKI over there. Here are max treble cut curves for one particular build:

PW3B_LPF_v4_TrebCut.jpg

 

But I've found that how you set up resonant overshoot/damping at the response knee makes a great deal of difference in play feel, and there are quite a few other interesting nuances to dive into. Looking forward to seeing and hearing what you come up with.

  • Thanks 1

Share this post


Link to post
Share on other sites
1 hour ago, Passinwind said:

I think that's a good call. If you haven't already, you might want to take a look at my (non commercial, completely free) open source onboard preamp design on Talkbass. I'd be happy to send you the LTSpice model to play around with, but the schematic is already available in the project WIKI over there. Here are max treble cut curves for one particular build:

PW3B_LPF_v4_TrebCut.jpg

 

But I've found that how you set up resonant overshoot/damping at the response knee makes a great deal of difference in play feel, and there are quite a few other interesting nuances to dive into. Looking forward to seeing and hearing what you come up with.

Yes please! I'll PM you my email address. 

Have a fairly simple starting point laid out in LTspice and the curves look along the right lines, but I bow to your superior knowledge! 

  • Like 1

Share this post


Link to post
Share on other sites
5 minutes ago, Bigwan said:

Yes please! I'll PM you my email address. 

Have a fairly simple starting point laid out in LTspice and the curves look along the right lines, but I bow to your superior knowledge! 

I really enjoy helping other DIY'ers work through Spice modeling, and that's actually a big part of how I came to do this open source thing. Essentially, a friend dropped a working model in my lap, and I revised and adapted it to a DIY friendly format.

There are links in my Talkbass thread to some interesting prior art as well: https://www.talkbass.com/threads/the-passinwind-open-source-preamp.1259692/#post-19536322

Share this post


Link to post
Share on other sites

In case anyone is still interested in HPFs after about a week off ... the Broughton I bought got held up at customs who, together with Royal Mail, added a lovely charge of about £18, taking the cost of the pedal to about £118 all in.   The Thumpinator or another home-made options would have avoided this! 

 

 

 

  • Like 1

Share this post


Link to post
Share on other sites

Yup it's bad news that 20% VAT payable at the EU customs border on anything above £15 (i.e. pretty much everything) and then (broadly) a further 2.5% customs duty on top of that for gear above £135. This is unless you (or f&f) are bringing in this personally in which case you get a £390 VAT and Customs duty free allowance. Makes things seem very expensive compared to what our fellow bass players get gear for in the US. Having said that their health insurance doesn't come cheap!

@krispn's very helpful suggestion I got in touch with both Josh Broughton and also Tom George at COG to see if they could come up with any 24dB cut variants. Josh is not currently taking any bespoke orders and suggested getting a couple of his pedals to the trick - well the ideal combination for me would actually be the Thumpinator and the Broughton LPF / HPF but you're looking at > £300 with transport and taxes thrown in for these two, which is getting a little spendy.

The exciting news (for me anyway!) is that Tom, with some spec suggestions thrown in from me, seems to have come up with something that could fit the bill in a single 1590BS enclosure pedal. Hoping to be able to confirm the agreed specs with you all shortly...

  • Like 3

Share this post


Link to post
Share on other sites

Micro Thumpinator just gone up for sale on the Bass Players Market UK Facebook group. Priced at £90. Get it while it’s hot!

 

Edit: never mind, turns out it’s on here as well!

Edited by CameronJ

Share this post


Link to post
Share on other sites

These are the specs I have provisionally agreed a couple of weeks back with Tom at COG.

  1. Fixed HPF with 12dB cut at 28 Hz
  2. Variable 12dB cut at HPF 20Hz to 400Hz (to deliver the desired 24dB HPF cut at 28Hz and below with a combination of the fixed and variable HPF)
  3. Variable LPF 12dB cut at 700Hz to 14kHz 
  4. Two true bypass switches: one for the two HPF filters, a second one for the single LPF filter; and
  5. Volume control to add +20db (to compensate, if required, for the effect of the cut being caused by engaging the filters)

With the unit housed in a 1590BS (11.2cm x 6.0cm x 3.8cm)

... although I've had radio silence for a couple of weeks from Tom which is always a little frustrating, but I guess he's busy.

What do folk think about the spec? Any other folks interested in getting something like this?

@Bigwan - something you could put together? If so, please PM me with your thoughts on pricing (I can't be doing with waiting for Tom to get back to me forever :) )

  • Like 1

Share this post


Link to post
Share on other sites
1 hour ago, Al Krow said:


@Bigwan - something you could put together? If so, please PM me with your thoughts on pricing (I can't be doing with waiting for Tom to get back to me forever :) )

Yes, but I'd likely take longer and produce something considerably less professional looking than what Tom could do! 

Share this post


Link to post
Share on other sites
36 minutes ago, Bigwan said:

Yes, but I'd likely take longer and produce something considerably less professional looking than what Tom could do! 

Hah! In which case I'd best just wait patiently for his response then :) 

Share this post


Link to post
Share on other sites
2 hours ago, Al Krow said:

Hah! In which case I'd best just wait patiently for his response then :) 

Julian Pohler's upcoming Vong kit is pretty close to what you're looking for. 

Share this post


Link to post
Share on other sites
Just now, Bigwan said:

Julian Pohler's upcoming Vong kit is pretty close to what you're looking for. 

Sounds interesting - you got a link?

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.


  • Recently Browsing   0 members

    No registered users viewing this page.

×
×
  • Create New...