How important is the sidechain HPF for a bass compressor?

[Zooberwerx]

Preach!

Agreed. I value a blend and well-executed single compression knob over & above dedicated parameter controls (attack, release, ratio, threshold), even metering.

Riis

 

[Mr_BK]

The Empress will probably do what you want if you actually know what you want and and take the time to learn how to make the Empress do it.

I would guess that for most bass players that is not the case and a simpler compressor will generaly yield better results. It will compress the bass signal with less margin of variables that could take the effect further away from the desired output.

 

[colin0154]

On the Empress, the center points on all the controls are all good starting points - if you don't know what you are doing, set everything at noon, and it'll sound fine. As you learn, you have the flexibility to do things with it that a compressor with less controls won't do.

That's definitely makes me more into Empress compressor. I don't have much experience with attact/release settings though, and some of my friends say that they calculate the release time with song BPM, which is impractical when playing multiple songs with different BPM at stage.

 

[Zooberwerx]

That's definitely makes me more into Empress compressor. I don't have much experience with attact/release settings though, and some of my friends say that they calculate the release time with song BPM, which is impractical when playing multiple songs with different BPM at stage.

That sounds more like a delay-associated tap tempo.

Riis

 

[NKBassman]

I've reviewed more than 100 compressors now and that has led me to believe that I personally do appreciate an adjustable side chain filter. That said, I value a wet/dry blend more. Read my reviews of both of the compressors the OP is considering here: Compressor Pedal Reviews | More than 100 compressors reviewed

I agree.

 

[NKBassman]

Applying EQ in the sidechain, definitely has an impact how sensitive a compressor is to different frequencies.

Let's a say a compressor responds equally to all frequencies and the threshold is set to 0dB. Any frequency that goes above 0dB will trigger the compressor. It does not matter what frequency exceeds the compressor threshold, compression will be applied to the full bandwidth of the signal.

This shows a 6dB per octave HPF set to 2khz.
View attachment 7442264

Let's imagine this 2k HPF is inserted in the sidechain of our compressor. Now, the level in the sidechain is attenuated -3dB at 2k; so the compressor will be 3dB less sensitive at 2k. In other words now +3dB is required to trigger the compressor at 2k. However at some point above 2k, the compressor is still triggered by exactly 0dB.

At 250hz the level in the sidechain is attenuated by -18dB; so the compressor will be 18dB less sensitive at 250hz. Now +18dB is required at 250hz to trigger the compressor.

At 125hz the level in the sidechain is attenuated -24dB; so the compressor will be 24dB less sensitive at 125hz. Now +24dB is required at 125hz to key the compressor.

For all practical purpose the compressor is not going key off low frequencies, because the signal in the side chain is attenuated so far below the threshold.

That doesn't mean the low frequencies won't be compressed. Anytime the signal at the detector goes above 0dB, compression will be applied to the full bandwidth of the signal.

It's just semantics. On a system level yes, the comp is less sensitive at frequencies below the HPF knee. At the component level, the sensitivity of the compressor hasn't changed, only the content of the detector signal.

We are in agreement, just different ways of looking at what's going on.

Carry on.

 

[wolffire99]

If I’m going to for fat flatwound pick sound I turn HPF side chain off so it hits compressor harder. Otherwise, much more natural compression with it on.

 

[ElectricBass72]

I like my Empress Compressor.

 

[el murdoque]

This year I'd like to upgrade my comrpessor pedal, but I can't seem to decide between Empress Bass Compressor and the Trickfish VCA Compressor. One of the difference is the variable sidechain HPF.

I know how sidechain HPF works, which only affects the detect signal, but I'm wondering how important is that? Why isn't it a norm for the bass compressor?

Or is it possible that most compressors designed for bass have some fixed HPF built in the sidechain?

It's quite simple.
Just buy a few compressors and try it out for yourself, in your personal circumstances and signal chain, and judge by feeling and ear.
Start with the ones you singled out, and maybe get a Cali76, a capable tube comp like the Effectrode LA-1A, the Keeley Bassist, the MXR M-87, one of the Becos (all are good), the RMI/Lehle Dual Band Comp and the Diamond Bass Comp as a start.

 

[Bob_Ross]

FWIW I spent 20 years as a full-time professional recording and live sound engineer, and in all those years I can probably count the number of times I used a high pass filter in the sidechain of a bass compressor on one hand. Maybe two hands.

 

[Moredator]

I like to get ~6dB of gain reduction across all my strings so I highpass around 100hz. I find it very important for more consistent sound between the strings.

 

[kyral210]

The MXR M87 doesn’t have one, and it’s an excellent compressor. So I’m going with ‘not that important’.

 

[Sam_Empress]

An external side chain source would be more accurate relative to the post I was quoting where I reference another use case for the sidechain input on the Empress which bypasses its internal sidechain HPF.

Some great info in this thread, and we love seeing our Bass Compressor come up in these discussions!
To be certain: The sidechain path on the Empress Bass Compressor goes sidechain insert (the 'input' is normalized to the sidechain if unpatched) -> HPF , the sidechain input does not bypass the internal SC HPF.
With that in mind, you can still tweak the HPF, Attack, Release, and Ratio settings even when using external sources for sidechain on the return. However, you cannot control the amplitude of the external sidechain signal with the 'input' control, that comes before the sidechain circuit and only affects the signal coming into the 'input' jack.