Why 40Hz for most preamps?

[-=DanAtkinson=-]

This is related to my thread about on-board preamps, which I know very little about, being a passive guy.

I have some background in recording & mixing. One of the keys to a good mix is cutting the "mud" and rumble in the bass, and carving things up so that the bass and the kick each have their own "space" in the frequency range. You don't want the bass and kick stepping on each other.

A common solution is to rolloff the boomy frequencies on the bass, like everything below 60Hz. So I was surprised to see that most active preamps center the bass control at 40Hz. That's way low. I'd prefer a boost around 80-100Hz instead. Does anyone know of a pre like that?

[JackANSI]

Maybe it has something to do with curve they've selected behind that control? Who knows what goes on inside the mind of an EE...

That being said, the more time I spend with it, the more I like the Stingray's 2-band EQ. I read a thread somewhere else.. can't remember where.. that said it lives in a wide band between 20 and 100hz with a center around 50...

[A440Hz]

One reason for the 40Hz center point is that it's usually a shelving control. For such a shelving filter, the center point is the midpoint of the shelf. The shelf actually goes a decade above and a decade below in action (4Hz - 400Hz). That creates quite a bit of action below 400Hz, then.

That's assuming a certain kind of filter and certain filter parameters. The shelf slope can be designed more steeply, and the filter f0 could be spec'd as the end of the range (e.g., a 40Hz shelf with 40Hz as the corner point of the shelf, not the midpoint).

Sounds like your listening with your ears, and not your eyes, and that's a good thing. But there are good purposes for such low filters. The old Pultec has the low control switchable to 20, 30, 60, or 100Hz. I believe that's a shelf and not a peaking EQ.

[mongo2]

Originally Posted by JackANSI

Who knows what goes on inside the mind of an EE...

Being an EE, I might.

[Marcus Willett]

Originally Posted by -=DanAtkinson=-

I'd prefer a boost around 80-100Hz instead. Does anyone know of a pre like that?

The Demeter onboard pre has a bass control centered at 100Hz, IIRC. Great sounding pre too, but a bit on the bright side.

[A440Hz]

Who knows what goes on inside the mind of an EE...

Originally Posted by mongo2

Being an EE, I might.

+1. Not much good, I assure you.

[FunkMetalBass]

Personally, when I think of boosting bass, I think of the low/low-mids and fattening up my tone. At mastering time, they can cut the sub-40hz frequencies, but from my bass, I want to keep them boosted.

Any chance you could boost the bass frequencies on your bass and then run through a HPF set around 40hz? You really wont find an onboard preamp with the 80-100hz center. And even if you did, it would still boost the low "mud" frequencies as well.

[line6man]

As mentioned, 40Hz is only the center frequency of a shelving control.

[A440Hz]

There may be some confusion in thinking that 40Hz (or whatever the bass control is) is the center of a peaking EQ or something. If it's shelving, it's not peaking.

For shelving filters, there's really a lot of effect on the mid-bass, too. One of the reasons that Neve and Pultec EQs are so renowned and "musical" is because of their gentle slope on the highs and lows and the pronounced effect of the bass and treble controls on neighboring frequency regions.

http://www.manleylabs.com/PDF/PRO_Ma...C%20manual.pdf

Pages 11 and 12 in that manual are full of great pictures.

[line6man]

Originally Posted by A440Hz

There may be some confusion in thinking that 40Hz (or whatever the bass control is) is the center of a peaking EQ or something. If it's shelving, it's not peaking.

You know what I meant.

[witness]

Originally Posted by -=DanAtkinson=-

This is related to my thread about on-board preamps, which I know very little about, being a passive guy.

I have some background in recording & mixing. One of the keys to a good mix is cutting the "mud" and rumble in the bass, and carving things up so that the bass and the kick each have their own "space" in the frequency range. You don't want the bass and kick stepping on each other.

A common solution is to rolloff the boomy frequencies on the bass, like everything below 60Hz. So I was surprised to see that most active preamps center the bass control at 40Hz. That's way low. I'd prefer a boost around 80-100Hz instead. Does anyone know of a pre like that?

Performanceguitar.com has a preamp, the BP-300 with the bass at 60hz +/-24db, not sure how it will sound, but I will find out after they finish my bass

[A440Hz]

Originally Posted by line6man

You know what I meant.

I wasn't disagreeing with anything you said. I was piling on. Sorry that wasn't clear.

[FunkMetalBass]

Dan, this may interest you. It's a 3-band EQ with frequency controls for each band.

http://www.noll-electronic.de/sites_e/tcm_3p.html

[Alivefor5]

The 3 band Audere preamp bass control is shelving centered at 80 hz.
The 2 band Audere preamp bass control is shelving centered at 100 hz.

[-=DanAtkinson=-]

Originally Posted by FunkMetalBass

Dan, this may interest you. It's a 3-band EQ with frequency controls for each band.

http://www.noll-electronic.de/sites_e/tcm_3p.html

Looks awesome. But I'm not seeing any source in the USA.

[joeyl]

you should go with an active filter system, no set frequencies of any kind

[FunkMetalBass]

Originally Posted by -=DanAtkinson=-

Looks awesome. But I'm not seeing any source in the USA.

No, they'd have to come from overseas. I didn't realize a local source was an important factor. Who knows - you might even be able to collaborate with the manufacturer and become a dealer of their systems.

Think of it as a business opportunity.

[G.Bisson]

I have always assumed 40Hz was used because it is approzimately the frequency of the note 'E1', an open E on four string bass. Centering the EQ band at that frequency makes open E's very predominant in the mix by boosting the fundamental.