Bass pedal

[Ben N]

Amazing, thanks for that Ben.

No problem it's the least (and probably also the most) I can do. But when you finally hatch this thing, please call it the Fantasia. A guy named Tallis (or Tallys) should really have a Fantasia.

[tallis]

Thanks to all!  Some really useful stuff.  Definitely got a better idea of how to achieve what (I think) I want.

Andy, you're definitely right about things muddying up when miking up a cab owing to the physical nature of the endeavour.  Clearing that up is definitely one of the benefits of the mixing technique I described.

I should say, I'm a bassist myself (I call myself one anyway!) and my objective is really to have a distortion sound coming out of my amp that has more clarity in the bottom end to start off with.  It's not so much the low-mid mush that's the problem really, although I know exactly what you're talking about.  It's the fact that the bottom end itself is less solid when you apply distortion - any distortion really.  Spongier somehow and lacking focus.  That's what I think I have a chance of mitigating.

You right - what I realise I need to do is "design" the pedal using plugins, and then reamp it into an actual cab, and see how it sounds.  Also to try an experiment with the tonal preemphasis you're talking about to see if I can pull back some of the clarity in the lows, while keeping them consistent.  Will post up the results.

Thanks again for your time and experience.  Looking forward to seeing what I get.

[tallis]

Amazing, thanks for that Ben.

No problem it's the least (and probably also the most) I can do. But when you finally hatch this thing, please call it the Fantasia. A guy named Tallis (or Tallys) should really have a Fantasia.

"Fantasia," it is!

[phasetrans]

...It's the fact that the bottom end itself is less solid when you apply distortion - any distortion really.  Spongier somehow and lacking focus.  That's what I think I have a chance of mitigating.

Any nonlinear circuit produces sum and difference tones. Some of those are related to the fundamental by simple intervals (harmonics), and some do not (intermodulation or IMD). The IMD plus the reduction in amplitude of the attack amplitude are just effects of the clipping process. Which is why the distortion character you experience is universal.

Human hearing doesn't really prefer distant perfect harmonics, see for example the different tuning temperaments of a piano. Also we tend to not like an-harmonic content (i.e. IMD), or harmonics well away from the fundamental (i.e. "fizziness"). By narrowing the bandpass in which we create harmonics, we reduce the amount of IMD. Then we usually post filter the very high harmonics for fizziness. That can be an electrical post filter, or it can be an acoustic low pass filter (i.e. guitar or bass speaker).

As the amount of clipping increases, tones tend towards the midrange. This is due to bandpass pre-filtering before clipping that helps reduce IMD and upper harmonics. The frequency of midrange focus can (and does) change, but the general trend is towards a central bandpass filter region.

Sometimes people reverse the pre-filtering after clipping for more neutral overall tone, but often they don't. So many "tight" distortion circuits also have minimal low frequency content.

Tube amps give you back some lows, and cut some highs, by the electro-mechanical nature of their power section:
-A tube amp has a comparatively high "output impedance." This means that overall frequency response of the speaker is changed by the amplifier circuit, the mechanical frequency response of the cone, and the electrical impedance of the voice coil "reflected" back through the output transformer.
-The net result of these behaviors is a boost to the top end (mostly from the cone) and a boost to the low end (from the coil impedance and electrical damping of the speaker).
-Then there is an overall low pass filter behavior. Part of that low pass is from the acoustic response roll-off of the guitar/pass speaker, and the rest is from flux modulation of the output transformer.

---

For a COTS pedal that might do what you want, the Billy Sheehan Signature bass overdrive gives you a clean and dirty path (pretty common for bass guitar effects), but also an effects loop for each branch of the circuit for inserting other stuff (which I haven't seen): https://ebssweden.com/content2/effects/ebs-billy-sheehan-ultimate-signature-drive/

[marcelomd]

For a COTS pedal that might do what you want, the Billy Sheehan Signature bass overdrive gives you a clean and dirty path (pretty common for bass guitar effects), but also an effects loop for each branch of the circuit for inserting other stuff (which I haven't seen): https://ebssweden.com/content2/effects/ebs-billy-sheehan-ultimate-signature-drive/

Billy Sheehan's pedal also has a compressor on the clean path. Billy himself uses another unit of the same pedal to put a bit of hair in the clean signal.

[phasetrans]

For a COTS pedal that might do what you want, the Billy Sheehan Signature bass overdrive gives you a clean and dirty path (pretty common for bass guitar effects), but also an effects loop for each branch of the circuit for inserting other stuff (which I haven't seen): https://ebssweden.com/content2/effects/ebs-billy-sheehan-ultimate-signature-drive/

Billy Sheehan's pedal also has a compressor on the clean path. Billy himself uses another unit of the same pedal to put a bit of hair in the clean signal.

I missed the compressor, that's great. My long time friend Andy knows Billy pretty well, and it's clear from listening to Andy talk about their discussions together, that Billy has a technicians mind. I could see him as the type that would lurk here.

[tallis]

For a COTS pedal that might do what you want, the Billy Sheehan Signature bass overdrive gives you a clean and dirty path (pretty common for bass guitar effects), but also an effects loop for each branch of the circuit for inserting other stuff (which I haven't seen): https://ebssweden.com/content2/effects/ebs-billy-sheehan-ultimate-signature-drive/

Billy Sheehan's pedal also has a compressor on the clean path. Billy himself uses another unit of the same pedal to put a bit of hair in the clean signal.

OMG unreal! I have to check this out when I get chance.  Sorry been teaching all day!  Looks brilliant, thanks!

I missed the compressor, that's great. My long time friend Andy knows Billy pretty well, and it's clear from listening to Andy talk about their discussions together, that Billy has a technicians mind. I could see him as the type that would lurk here.

[Fancy Lime]

A quick follow-up on intermodulation distortion (IMD): Keeping IMD in check is actually one of the reasons why most drive pedals boost the treble or cut the bass before the clipping stage(s). If you don't then you end up with a fuzz rather than a distortion. For guitar this really matters a lot because there you often play chords (at least power chords) through the distortion device, meaning you get the sums and differences of, e.g. a fundamental, it's fifth, and it's octave. I love the resultant discordant mess, most people don't. For bass, this aspect is less relevant since you normally play single notes whenever heavy distortion is involved. Unless you are trying to get kicked out of the band. With single notes, IMD can only produce the sums and differences of the fundamental and it's own natural overtones and  harmonic distortion products. And what are those? Thought experiment: a 100Hz note is played. The first overtone is the octave at 200Hz. Sum with the fundamental is 300Hz, which is the fifth above the octave and also the second natural overtone and the third harmonic. The difference between 200Hz and 300Hz is the fundamental again, whereas the sum is 500Hz, yet another harmonic overtone. The point being: IMD ist not a big deal with single notes unless you have very hard clipping with strong high order harmonics because the higher overtones are actually sharp due to the tensioning of the string by it's own vibration. But for bass I would advocate soft knee clipping with few high order harmonics anyway. But IMD is certainly a fascinating topic worth keeping in mind when designing any distortion device.

Cheers,
Andy (no, not that one)

[phasetrans]

Cheers,
Andy (no, not that one)

Based on what I've read of your work here, I imagine that you'd get along well with the Andy in question. Do you happen to be in Nashville / Brentwood?

[DIY Bass]

I have a Deluxe Bass Big Muff on my board. It has the distortion of a big muff, with a clean/dirty blend, but also has a foot switchable crossover so only the top end is sent to the distortion if you want.  I have never seen a schematic though, so it might be tricky to do as a DIY build with mods.

[willienillie]

For a COTS pedal that might do what you want, the Billy Sheehan Signature bass overdrive gives you a clean and dirty path (pretty common for bass guitar effects), but also an effects loop for each branch of the circuit for inserting other stuff (which I haven't seen): https://ebssweden.com/content2/effects/ebs-billy-sheehan-ultimate-signature-drive/

Billy Sheehan's pedal also has a compressor on the clean path. Billy himself uses another unit of the same pedal to put a bit of hair in the clean signal.

And didn't Billy Sheehan come to us from a band called Talas?

[12Bass]

FWIW, the Tech 21 Geddy 2112 and YYZ and DP-3X along with the Darkglass X series pedals employ a similar approach, whereby the mids/highs are distorted and mixed with a clean LPF path.  Compression is also used in the LPF path of some circuits.  This provides the ability to add some grind to the top end whilst keeping the lows clear and deep.

[tallis]

For a COTS pedal that might do what you want, the Billy Sheehan Signature bass overdrive gives you a clean and dirty path (pretty common for bass guitar effects), but also an effects loop for each branch of the circuit for inserting other stuff (which I haven't seen): https://ebssweden.com/content2/effects/ebs-billy-sheehan-ultimate-signature-drive/

Billy Sheehan's pedal also has a compressor on the clean path. Billy himself uses another unit of the same pedal to put a bit of hair in the clean signal.

0

And didn't Billy Sheehan come to us from a band called Talas?

Ha! Unreal!

[phasetrans]

While I have a captive audience of bass players, indulge a digression that I have considered building as an effect:

Background
I have 20 years of experience in live sound. Primarily as system tech and mixer. Splitting bass guitar at the console into two inputs has been standard for me for better part of a decade. One channel carries the mids, and the other lows. Different compression on each, some reverb and/or chorus on the mids channel. I primarily ride the mids channel to keep bass planted in the mix.

effect idea
-Mid boost with effects loop on a "smart" switching
-Circuit is clean path plus mid boost path.
-You can set the upper and lower mid boost corner frequencies with knobs, and also amount of boost.

Foot Switch operation (proposed)
1. Momentary press latches the mid boost on
2. Press and hold makes the mid boost momentary
3. Holding latched boost switch keeps boost engaged until release
4. Double press latches both mid boost and effects loop. Or maybe some selectable logic about when to include the effects loop with the boost.

The idea is to let the bass player push the mids when they know that they need them, based on what they are playing.

Thoughts? Would anyone use it?

[tallis]

While I have a captive audience of bass players, indulge a digression that I have considered building as an effect:

Background
I have 20 years of experience in live sound. Primarily as system tech and mixer. Splitting bass guitar at the console into two inputs has been standard for me for better part of a decade. One channel carries the mids, and the other lows. Different compression on each, some reverb and/or chorus on the mids channel. I primarily ride the mids channel to keep bass planted in the mix.

effect idea
-Mid boost with effects loop on a "smart" switching
-Circuit is clean path plus mid boost path.
-You can set the upper and lower mid boost corner frequencies with knobs, and also amount of boost.

Foot Switch operation (proposed)
1. Momentary press latches the mid boost on
2. Press and hold makes the mid boost momentary
3. Holding latched boost switch keeps boost engaged until release
4. Double press latches both mid boost and effects loop. Or maybe some selectable logic about when to include the effects loop with the boost.

The idea is to let the bass player push the mids when they know that they need them, based on what they are playing.

Thoughts? Would anyone use it?

It's a really cool idea if you could get it to work.  I personally wouldn't use it - I tend to have quite a middy clean sound anyway, just play with dynamics and add distortion when I need it.  But if some bassist wanted a tone boost it might be useful for them.  Bassists are easily confused (I'm allowed to say that!) so I would try simplifying the operation, just latch on and off, and maybe add another foot switch for an fx loop.

Hope that helps.

Good luck!

T

[tallis]

OK drumroll......
I've dont the experiments, and the results are in.  I thought before saying what I thought, I'd share my method with you and let you respond.

I did three experiments:
- A "control" experiment, where I just fed a DI signal through an emulated stomp box distortion.
- One with a single band distortion with matched pre- and post-emphasis tilt EQs to favour treble on the way in and bass on the way back out.
- One with a dual band approach, as per original idea - one split goes distortion then HPF, the other goes LPF then compression. Then blended. Crossover was 220Hz.

I then reamped them all separarely through a Hartke head and Laney 4x10 and miked up the best speaker with a neutral condenser mic.  The results  can be heard here:
https://soundcloud.com/tomhenthorn/sets/bass-experiments

...and you can see below what I did with the plugins.

DISTORTION ONLY


SINGLE BAND WITH PRE- AND POST-EMPHASIS EQ


DUAL BAND: DISTORTION TO HPF, AND HPF TO COMPRESSOR



Tell me what you think!
T

[marcelomd]

Single band pre/post emphasis sounds the best to me, which is a surprise. A bit of tone shaping and it's pretty good.

[phasetrans]

OK drumroll......
I've dont the experiments, and the results are in.  I thought before saying what I thought, I'd share my method with you and let you respond.

I did three experiments:
- A "control" experiment, where I just fed a DI signal through an emulated stomp box distortion.
- One with a single band distortion with matched pre- and post-emphasis tilt EQs to favour treble on the way in and bass on the way back out.
- One with a dual band approach, as per original idea - one split goes distortion then HPF, the other goes LPF then compression. Then blended. Crossover was 220Hz.

I then reamped them all separarely through a Hartke head and Laney 4x10 and miked up the best speaker with a neutral condenser mic.  The results  can be heard here:
https://soundcloud.com/tomhenthorn/sets/bass-experiments

Tom,

Of these three, I prefer #2.

BUT, I think for #3 you should do the filtering first, and then the distortion. I also think you need a bit more makeup gain on the compressor to better match the overall tonal balance of the other two clips. I would try a crossover frequency of 175Hz. Somehow that's where I usually end up with when behind the live desk.

[Fancy Lime]

Thanks for posting the tracks! I am actually a bit surprised how subtle the differences are. I also like the second version best, but that's no dramatic twist at this point in the thread, is it? All in all it seems to me that if you add a bit of tasteful EQ in post to get the best sound out of each version, I might find it difficult to tell which is which in a band context. That being said, track three nicely demonstrates what I personally dislike most of the time about the splitting method: it always sounds a bit like two separate instruments playing in unison to me. That can be good for a wall of sound or as a deliberately extreme effect for bass intros and such but most of the time I prefer to have a clear cut monolithic bass sound that is easy to spot in the mix. Seems to me that both methods have their place depending on the role of the bass player in the particular band and the desired overall band sound.

Cheers,
Andy

[phasetrans]

...
effect idea
-Mid boost with effects loop on a "smart" switching
-Circuit is clean path plus mid boost path.
-You can set the upper and lower mid boost corner frequencies with knobs, and also amount of boost.

Foot Switch operation (proposed)
1. Momentary press latches the mid boost on
2. Press and hold makes the mid boost momentary
3. Holding latched boost switch keeps boost engaged until release
4. Double press latches both mid boost and effects loop. Or maybe some selectable logic about when to include the effects loop with the boost.

The idea is to let the bass player push the mids when they know that they need them, based on what they are playing.

Thoughts? Would anyone use it?

It's a really cool idea if you could get it to work.  I personally wouldn't use it - I tend to have quite a middy clean sound anyway, just play with dynamics and add distortion when I need it.  But if some bassist wanted a tone boost it might be useful for them.  Bassists are easily confused (I'm allowed to say that!) so I would try simplifying the operation, just latch on and off, and maybe add another foot switch for an fx loop.

The feedback is helpful, but I think that latch only defeats the purpose of being able to provide the bump intermittently based on what is being played.

What about two different foot switches (one for loop, and one for boost). You can pick them latching or momentary with a clear toggle, and you can either link or separate their actions?

The vast majority of live sound people that have an instrument, in my experience, are bass players. So maybe there's a technically minded subset of bass players? I don't see guitar players doing crossovers or clean/dirty mixing on their pedalboards...