Bass pedal

[tallis]

Yes I was pretty surprised how subtle the differences are too, but I think they're big enough to make a difference. Distortion only is very raw and punky, which I like. The pre- and post-emphasis one has a much cleaner and dynamic bottom end, which is also nice. From my own perspective, I like the third one the most, because the bottom end is much more constant. I know what you mean about being slightly disjointed, but a clear and constant rumble under the guitars is what I'm more after really. Dynamics can do one! ...well until I take distortion off anyway.

Interestingly, I couldn't get 6dB filters to work to my taste. Too much of the clean string noises were getting through (which is actually what I disliked about the Billy Sheehan pedal, ingenious though it is). So I had to go 12dB/oct. So looks like 2 state variable filters.

Thanks to whoever suggested doing the experiment. I've learned quite a bit about what I'm really after. And generally for your comments. I'll keep you informed on the build.

Peace!

[tallis]

...
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...

...guitarists are just show-offs! (I'm allowed to say that as well being both!) I think the point is that a good bassist is part of a good rhythm section, which really underpins the music. If the rhythm section works properly, the others can get away with doing what they like. Maybe we're just happy to do a vital job and be completely ignored!

On the proposed pedal, yeah that might just work, y'know. Good luck!

[12Bass]

Yes I was pretty surprised how subtle the differences are too, but I think they're big enough to make a difference. Distortion only is very raw and punky, which I like. The pre- and post-emphasis one has a much cleaner and dynamic bottom end, which is also nice. From my own perspective, I like the third one the most, because the bottom end is much more constant. I know what you mean about being slightly disjointed, but a clear and constant rumble under the guitars is what I'm more after really. Dynamics can do one! ...well until I take distortion off anyway.

Interestingly, I couldn't get 6dB filters to work to my taste. Too much of the clean string noises were getting through (which is actually what I disliked about the Billy Sheehan pedal, ingenious though it is). So I had to go 12dB/oct. So looks like 2 state variable filters.

IIRC, the Sheehan pedal does not use a LPF in the clean path, allowing clean finger/string noise to come through.  The DP-3X and Microtubes X series pedals use a LPF in the clean path.  Also, consider raising the frequency on the HPF going to the clipping stage, as it makes quite a difference in the sound quality of the distortion produced.  The DP-3X uses pretty high frequency (above 1kHz IIRC), which gives it a very characteristic metallic clanky/grind. 

Compression on the clean LPF path helps to keep the dynamics under control and more closely matched with the natural compression derived from clipping the HPF path.  Carefully dialing in the HPF and LPF frequencies and relative blend of the two makes a huge difference in terms of how cohesive or "together" the resulting sound turns out.  I'd suggest experimenting by playing around with the frequencies and relative balance between the two paths and see what sounds "best" to your ears.   

[tallis]

Thanks for your thoughts. Appreciated.

[phasetrans]

Yes I was pretty surprised how subtle the differences are too, but I think they're big enough to make a difference. Distortion only is very raw and punky, which I like. The pre- and post-emphasis one has a much cleaner and dynamic bottom end, which is also nice. From my own perspective, I like the third one the most, because the bottom end is much more constant. I know what you mean about being slightly disjointed, but a clear and constant rumble under the guitars is what I'm more after really. Dynamics can do one! ...well until I take distortion off anyway.

Tom, let me validate that in a rock mix context I too would pick the evenness of #3. Against a full mix you don't notice the disjointedness, and the evenness of the LF is more important.

That said, I'm part-way through a pedal design, for guitar, where you can pick the frequency range of pre / post emphasis filters on either side of the clipping using a single knob. You can pick the clipping character by choosing how much of the lows and mids to cut before the clipping.

Interestingly, I couldn't get 6dB filters to work to my taste. Too much of the clean string noises were getting through (which is actually what I disliked about the Billy Sheehan pedal, ingenious though it is). So I had to go 12dB/oct. So looks like 2 state variable filters.

Behind the live desk, I also use 2nd order LPF and HPF. I would use 12 dB/octave filters in the mid boost pedal I proposed. Regarding corner frequencies, I will set the LPF 170-180Hz on the low channel, and the HPF on the mids channel at 280-300Hz. I usually run around 5dB more makeup gain on the mid channel compressor than the LF channel, hence the gap in the filter corner frequencies.

Compression settings (for rock):
Low Channel
4:1, hard(ish) knee, 3-8ms attack, 50-80ms release

Mids Channel
4:1, softer knee, 1-5ms attack 25-50ms release

Since it seems like you are mixing music that is more aggressive than what I normally used to, I would be curious if something like the settings above work for you in a mix.

[phasetrans]

...guitarists are just show-offs! (I'm allowed to say that as well being both!) I think the point is that a good bassist is part of a good rhythm section, which really underpins the music. If the rhythm section works properly, the others can get away with doing what they like. Maybe we're just happy to do a vital job and be completely ignored!

On the proposed pedal, yeah that might just work, y'know. Good luck!

I don't think I would try a guitar pedal with a "bump" and latching options, as I would expect most guitar players to "latch it and leave it"

The more I think about the mid bump pedal, it should probably be on a toggle that provides either +2dB or +4dB fixed gain boost on the selected mid frequencies

[Fancy Lime]

Hi Tom,

Ok so you got clearity about your principle architecture. Time to tackle the details then. I would advocate Sallen-Key filters for the second order hpf and lpf. These are much simpler than state variable filters and work just as well in you application. Do you have a specific kind of distortion and compressor in mind yet? Distortion is probably the effect that is most subject to personal taste so I will hold my breath with smartassing on that. For now  For the compressor, I would go with an optical design. They are pretty simple, low noise and easy to tune to a really fat bass sound. DOD 280 or the Lightspeed Compressor are simple and really good. OPA designs are more flexible but also more finicky, more noisy and typically more subtle. Merlin's Engineer's Thumb is great though. Search for it in this forum. JFET compressors even more so except for the noise. VCAs are expensive(ish) and therefore not awfully common in diy designs. Most other options are even more complicated or involve expensive or hard to get parts.

Andy

[phasetrans]

Echoing Andy and expanding on filtering:

1. If you fix the frequency, then sallen key is easier to implement.

2. A fixed sallen key pair, but adjustable bandpass levels has the functional effect of shifting around the corner frequencies

3. If you want the crossover frequency adjustable, you could copy the Elliott Sound state variable crossover: https://sound-au.com/project148.htm

4. You could uses the Sound Semiconductor SSI2140 quad filter to implement an adjustable sallen key HP/LP pair. Or similar idea with ssi 2164

5. You could also cheat the response by setting up one or two poles of fixed HP / LP at the boundaries of the range you want to control, and use another adjustable pole in between the ends of the bandpass with simple HP or LP

[11-90-an]

Compressor? @jonny.reckless's Poor Man's Compressor. Only uses common transistors.