Active Pre Amps - bass mostly 40hz?

[redbandit599 251]

1 hour ago, TrevorR said:

Setting the bass peak at 40hz seemed bonkers to me. Do most active circuits do that? Seems unlikely. Thought I’d have a look at my Audere preamp’s spec... I do love how that preamp sounds!

I can't claim to have conducted an extensive analysis, but certainly most that I have looked at seem to be 40hz.

That Audere has the highest bass frequency I've seen by a long way. Interesting! Glad you like it.

 

[redbandit599 251]

1 hour ago, TrevorR said:

The shelving control makes our specs look very different than most preamps. Our spec is at the 1/2 boost or cut frequencies.

This is probably the clue as to why. Though I've no idea what that second sentence means🤔

[acidbass 201]

3 hours ago, TrevorR said:

Setting the bass peak at 40hz seemed bonkers to me. Do most active circuits do that? Seems unlikely. Thought I’d have a look at my Audere preamp’s spec... I do love how that preamp sounds!

Wow, really interesting. I think a 200hz bass frequency (while a bit on the high side) would be infinitely more useful and musical than one set at 40hz. Also a fan of the mid and treble ranges. Will be looking into this pre for def!

[bloke_zero 128]

I think the Ampeg ultra lo and hi buttons do a thing, slight boost at 40, and dips the mids at 500. I remember trying it the first time and getting an instant "oh, thats how a recorded bass sounds" feel from it. I think there is a lot to be said from restrained use of shelving EQ. Though I'm more of a cut than boost guy.

[Jus Lukin 2,345]

11 hours ago, redbandit599 said:

This is probably the clue as to why. Though I've no idea what that second sentence means🤔

It means that the frequency centre is not where the greatest boost occurs- that happens lower. Not knowing the slope, it's hard to be exact but if it were ⅓ Oct, there would be no change from 210hz and up. At full boost of 16db, 180hz would be up by 8db, and the full 16db would be realsised by 150hz. If the slope is gentler at, say, an octave, then the boost would begin at 360hz, still be at 8db at 180hz, and realise the full 16db by 90hz. Of course being a shelf, all frequencies below that point will be boosted.

This would be easier with a pen and paper. If I come across an image I can post, I will!

[mcnach 2,477]

On 19/10/2020 at 06:46, E sharp said:

No idea what the bass frequency is set to , on the 3 band EQ's in my Stingray and Bogart , but it's higher than 40 , and very useful .

 

I checked this a while ago (years before the newer models came out) on the Ernie Ball forum:

Quote

Our 3 band basses use a standard baxandall circuit centered appx. 500hz. Frequency slope is 6 db per octave. With bass control in max position, max output will occur at 40hz and drop at 6db per octave above 40hz. Maximum treble response drops at 6 db per octave at frequencies below appx.12 khz. Mid range is centered appx.500 hz. Control settings are interactive, therefore 6 db per octave slope only occurs when one control is in maximum position and the two remaining controls are set to minimum.

 

So it looks like it extends higher than some other preamps, but the maximum boost is still around 40 Hz. However the 3EQ has an HPF too, which will remove some of the lowest frequencies too (I was unable to find the specs of this HPF at the time).

Edited October 22 by mcnach

[drTStingray 626]

This shouldn't really come as a surprise - the bass control on an amp is often centred on 40. However there are other controls (in some cases another three) - they also CUT as well as boost - so you can cut those frequencies (eg 40 hz) if you want to. 

[redbandit599 251]

19 minutes ago, drTStingray said:

This shouldn't really come as a surprise - the bass control on an amp is often centred on 40. However there are other controls (in some cases another three) - they also CUT as well as boost - so you can cut those frequencies (eg 40 hz) if you want to. 

Yes, a 40hz cut is handy, but imho probably better done on the amp. I do frequently boost the lows for a particular song or two mid gig via the bass controls - having a boost at 40hz isn't as useful as a cut at this range. 

A comment further back mentioned a control cutting at 40hz and boosting at 80hz. That sounds simple and covers both requirements. 

IME the additional mid controls are usually centred a bit higher and so don't boost lows.

 

 

[Stub Mandrel 8,091]

On 19/10/2020 at 12:36, bloke_zero said:

Don't forget shelving eq - Ampeg for example use james or baxendal looks like this:

Much nicer sounding to my ears - though I agree putting it at 40hz is limited!

The frequency is probably the point where the straight line in off the left is notionally (it varies with the amount of cut/boost) 3dB down.

If the full scale is 50dB, for the yellow and green I would say the 3bd point is probably not a long way from 40Hz on that plot. The magenta is a bit closer to 70-80Hz

Edited October 22 by Stub Mandrel

[drTStingray 626]

4 hours ago, redbandit599 said:

Yes, a 40hz cut is handy, but imho probably better done on the amp. I do frequently boost the lows for a particular song or two mid gig via the bass controls - having a boost at 40hz isn't as useful as a cut at this range. 

A comment further back mentioned a control cutting at 40hz and boosting at 80hz. That sounds simple and covers both requirements. 

IME the additional mid controls are usually centred a bit higher and so don't boost lows.

 

 

Yes a subject which divides opinion - however I use the onboard pre amp on the bass for minor adjustments between songs or even mid song - this usually entails a slight mid range bump for greater articulation, harmonics and prominence in the mix (where required by the song). I wouldn't want to do that on the amp although I might slightly up one of the mid controls if I feel the need - but that would stay for the set.

I also change pick up settings mid song - a very good example of this is in Stomp by the Brothers Johnson - using a twin pick up Musicman, the humbucker is selected for most of the song but both humbuckers for the slap section (different - more scooped sound). 

The point I was really making was that it's possible to cut the bass control which would also influence the 40 hz - however all the controls interact on basses and in any case they affect adjacent frequencies. 

As well as the practical issue of not being able to change the amp EQ readily, by having the tone controls on the instrument, the interaction of the player and their playing style with the pick up, bass and tone controls is different from the effect of adjusting the amp, which is more remote in the chain. Just the same as passive bass tone controls v tone controls in the amp - in reality most of us use both to an extent. 

I guess it depends on your viewpoint and what sound you're seeking. 

Edited October 22 by drTStingray
Apple induced spelling error

[itu 862]

11 hours ago, drTStingray said:

The point I was really making was that it's possible to cut the bass control which would also influence the 40 hz - however all the controls interact on basses and in any case they affect adjacent frequencies.

I do admit that this is pretty common, but there are solutions, where interactions are really limited to the specified bands. There's lots of bass specific stuff which is not studio quality, on the contrary. It is possible to design electronics up to the studio level (John East, anyone?), although a simple capacitor and a lousy carbon track pot seems to be the solution for many. Cost: under £1 in a £1659 Jazz ( https://www.thomann.de/gb/fender_am_original_60_j_bass_3tsb.htm ).

I understand Anthony Jackson's idea of having only the pickup in his Fodera. Obviously Mr. Jackson does not want any sound deteriorating component to his signal chain in studio. One Penny & Giles pot in a big mixing board costs easily as much as bag of carbon track Alphas.

[CameronJ 1,545]

I’ve always the thought the EQ from TC Electronic’s BH Series heads would be pretty cool in an onboard pre form. They put the same EQ section into the Spectradrive preamp pedal. 4 bands, with each band cutting at a different frequency than it boosts. The bass control cuts at 50hz but boosts at 80hz:

 

Having owned a BH800 head I can say it’s a very intuitive system and just makes a tone of sense.

Edited October 23 by CameronJ

[redbandit599 251]

25 minutes ago, CameronJ said:

I’ve always the thought the EQ from TC Electronic’s BH Series heads would be pretty cool in an onboard pre form. They put the same EQ section into the Spectradrive preamp pedal. 4 bands, with each band cutting at a different frequency than it boosts. The bass control cuts at 50hz but boosts 

That does look bang on for my tastes. Love a little boost at 800hz.

Who's going to tell TC to build it? 😉

[CameronJ 1,545]

11 minutes ago, redbandit599 said:

That does look bang on for my tastes. Love a little boost at 800hz.

Who's going to tell TC to build it? 😉

I doubt they ever will - the Spectradrive is as close as we’ll likely ever get.

Although I feel like it’s the kind of project John East @John-E-Retro could make happen! 

[TrevorR 1,292]

On 20/10/2020 at 22:41, redbandit599 said:

This is probably the clue as to why. Though I've no idea what that second sentence means🤔

Me neither - sounds fab, though!

[grenadillabama 75]

On 19/10/2020 at 12:29, drTStingray said:

If you mean the 2 band Musicman circuit, then that is boost and cut (but doesn't have a centre detent).

Ive also seen it described as a Baxendale type circuit. 

That Baxendale eq was also used well on old Vox stuff . It is well-liked , but not hard to understand. Those fancy narrow-wide Q preamps or Alembic controls are interesting .

[itu 862]

https://en.wikipedia.org/wiki/Peter_Baxandall

[ikay 239]

Here are the cut and boost freq curves for the Musicman 2-band.

Also an interesting technical article about the original Baxandall circuit https://learnabout-electronics.org/Downloads/NegativeFeedbackTone.pdf

[drTStingray 626]

Thanks for posting that again. It's very interesting and demonstrates how controls interact as well.

I said in an earlier post that I sometimes boost one of the mids on the amp when using a 2 band Stingray - it's to compensate for that mid cut.

Remember this bass was originally designed in 1976 - at that time everyone used a smiley face type EQ with Fender type basses - this bass put your sound into that direction straight out of the box and sounded more like a recorded bass sound.

Its worth remembering the original hang tag manual for a Stingray bass suggested moving the controls back towards centre from full to enhance the mids. So none of this is new at all!! 👍

To answer earlier points on 2 band Stingray pre amps, you can see both the bass and treble controls can cut as well, although the treble more so than the bass. @ped mentioned the frequencies changed over the years - for the 2 band it's the same since 1979 (there were several iterations of the original pre EB preamp. 

Those charts also demonstrate the point of adding a mid range control to it, and high pass filter to cut some of those lower, muddier frequencies out. It's how you use the mid control which gets you close to the 2 band sound. 

Edited October 24 by drTStingray

[krispn 1,088]

The tidal preamp as used on Alien Audio basses and available as a stand alone stomp box pre is really good! Designed by Mo West from SWR it’s a very musical pre and has a built in drive. Worth checking out some alien audio bass demos to hear it on you tube! Chopper from Alien Audio talks about each tone control working on more than one frequency centre so boosting works on more than just 40Hz on the bass for instance. I’m not sure if the technical spec for the unit but I’ve played one and really liked it. 

Edited October 25 by krispn