Double Bass EQ's...can't decide between graphic or parametric

[MR PC]

50hz, fairly narrow Q, is sometimes a good freq for "punch" on your money notes. It really depends on the room though and what kind of kick drum sound is going on in the moment.

 

[drurb]

I was fortunate to find a Fishman Dual Parametric on eBay. How can I learn to use it optimally with my AI Focus Series III for tone control?

I suggest that you take a look at this. I hope you find it helpful.

The tone controls on the Focus are as follows:
Bass: shelving type, +-15 dB @ 60Hz
Mid: +-15 dB @ 650 Hz
Treble: shelving type, +-25 @ 10kHz

...Trying to figure out optimal frequency points and octave widths to essentially replace the single mid control with low-mid and high-mid controls. I thought I'd try to replicate the frequency points of the AI Flex preamp (+-12dB @ 50, 250, 1200, and 8kHz). I currently have the two bands set at roughly 250 and 1200 with a one-octave (on each side of the center freq) spread; seems like those settings should result in a pretty even distribution, leaving the AI's mid control flat. (Probably a bit short on the high end, which isn't of much concern.) Thoughts?

The charm of a parametric is that you can set the center frequencies of the filters so that the sound can be tailored for each situation. That said, if given three filters, useful starting points for centers would, IMO, be 40-60 Hz, 500-1500 Hz, and 2-4 kHz. By that, I mean that I would choose center frequencies between those ranges. That is, for the first filter, somewhere between 40 and 60 Hz, and so on for the other two. I'd start with a bandwidth of a half-octave. For those not familiar with the terms, "Q" refers to the "quality factor" and is a term from the old radio days when sharper tuning filters were more desirable. Q = Center frequency (CF)/Bandwidth (BW). So, as the bandwidth relative to the center frequency goes down (i.e., a sharper filter), Q goes up. Keep in mind that humans are most sensitive to changes in the spectral profile in the region of 1 kHz. Just a couple of dB either way can substantially affect how "forward" or "nasal" things sound.

...Also, where on the frequency spectrum does bass "punch" exist to push through a 17-piece big band? Hard to tell from where I stand.

That would be roughly in the octave around 80-160 Hz.

 

[Michael Eisenman]

I suggest that you take a look at this. I hope you find it helpful.

The tone controls on the Focus are as follows:
Bass: shelving type, +-15 dB @ 60Hz
Mid: +-15 dB @ 650 Hz
Treble: shelving type, +-25 @ 10kHz



The charm of a parametric is that you can set the center frequencies of the filters so that the sound can be tailored for each situation. That said, if given three filters, useful starting points for centers would, IMO, be 40-60 Hz, 500-1500 Hz, and 2-4 kHz. By that, I mean that I would choose center frequencies between those ranges. That is, for the first filter, somewhere between 40 and 60 Hz, and so on for the other two. I'd start with a bandwidth of a half-octave. For those not familiar with the terms, "Q" refers to the "quality factor" and is a term from the old radio days when sharper tuning filters were more desirable. Q = Center frequency (CF)/Bandwidth (BW). So, as the bandwidth relative to the center frequency goes down (i.e., a sharper filter), Q goes up. Keep in mind that humans are most sensitive to changes in the spectral profile in the region of 1 kHz. Just a couple of dB either way can substantially affect how "forward" or "nasal" things sound.


That would be roughly in the octave around 80-160 Hz.

Thx, Les. Not sure about your 40-60 Hz recommendation for the first filter; I run my HPF around 60 Hz. Maybe put the first filter in the 80-160 range, use the AI's mid at 650, and set the second filter at 2-4 kHz?

 

[drurb]

Thx, Les. Not sure about your 40-60 Hz recommendation for the first filter; I run my HPF around 60 Hz. Maybe put the first filter in the 80-160 range, use the AI's mid at 650, and set the second filter at 2-4 kHz?

For some reason, I thought you had three parametric filters. I now understand that you have two. Given where you run your HPF, I think yours is a good idea. It's just a starting point. You may find that in certain venues, you need to change the CF of the filters to tame a specific problem. That's when that device should really come in handy.

 

[Groove Doctor]

Also, where on the frequency spectrum does bass "punch" exist to push through a 17-piece big band? Hard to tell from where I stand.

EQ can only go so far. First make sure you've got enough speaker surface area to match the room size/volume/band lineup.

I'll use a small combo in the small rehearsal room, but a 2x12 at our last outdoor gig (no PA).

 

[Michael Eisenman]

EQ can only go so far. First make sure you've got enough speaker surface area to match the room size/volume/band lineup.

I'll use a small combo in the small rehearsal room, but a 2x12 at our last outdoor gig (no PA).

I usually ask one of the singers whether I'm loud enough, or the director will tell me to turn up the volume. If our PA had room for me, I'd use a channel.

 

[MR PC]

Goes to show that it's different strokes for different folks with para eq. I typically cut the 80-120hz region about 2db with a medium sort of Q. I'll set and forget that, it works with bridge transducers for me. "Punch" is never a problem for me really, maybe it's my playing technique. If I do need "punch" from the fundamental, for whatever reason, a slight boost at about 50hz with a very narrow Q does the trick. That's usually when the rest of the band is playing to loud and the room sound is folding in, and sucking up the bass zone I always try to stay out of their freq zones, but sometimes you just have to push back. My take.

 

[Matthijs]

Hoe to eq in a big band ime largely depends on how crowded the band is in the lower register. If I have to compete with bariton saxes or tuba the 80hz range can be a last resort. Most of the time one octave up is the range that gets me through

 

[Peck_Time]

Hoe to eq in a big band ime largely depends on how crowded the band is in the lower register. If I have to compete with bariton saxes or tuba the 80hz range can be a last resort. Most of the time one octave up is the range that gets me through

It depends on your strings too- I find it easier with guts to hear myself, they sit in a nice spot. Spiros tend to sit in a more crowded register for me.

 

[drurb]

Goes to show that it's different strokes for different folks with para eq. I typically cut the 80-120hz region about 2db with a medium sort of Q. I'll set and forget that, it works with bridge transducers for me. "Punch" is never a problem for me really, maybe it's my playing technique. If I do need "punch" from the fundamental, for whatever reason, a slight boost at about 50hz with a very narrow Q does the trick. That's usually when the rest of the band is playing to loud and the room sound is folding in, and sucking up the bass zone I always try to stay out of their freq zones, but sometimes you just have to push back. My take.

Such is the problem with subjective adjectives to describe sound. I think it's true that the typical characteristic of "punch," as in when the sound seems to hit you in the chest is in the octave I noted. The DB has almost no output at 50 Hz. The fundamental of the open E is 41 Hz and it's the second harmonic (82 Hz) that has the most power. Of course, as soon as one goes above the E, any power near 50 Hz is reduced further. When you boost the 50-Hz band, the change you hear likely results from increasing the intensity of frequencies at the upper end of the band you're boosting. For example, if you're using a low-Q (narrow bandwidth) of, say, a 1/2 octave, then the 3-dB-down point above 50 Hz is a quarter-octave above that, or ~60 Hz. Then, depending on the slope of the filter, the boost trails off above that.

Still, if that scheme works best for you, then so be it. No argument. I'm just trying to point out what's going on physically.

 

[MR PC]

All of that is true..and remembering he louder we play, the further we get from the true sound of an acoustic bass. Instead of reinforcing the acoustic sound, the bass becomes more of an electric instrument. Some very famous jazz bassists have distorted the general public's perception of what an acoustic bass sounds like by dumping mics altogether and going direct to the board with a pu. I recently had a tizzy with an engineer who told me pickup "X" was the best sound he'd ever heard from an acoustic bass. In reality, all pickups and microphones distort the sound of acoustic instruments. In the end, it's really a fools errand, trying to hear yourself over a bandstand full of musicians who strive for recorded sounds, not acoustic sounds. God bless Leo Fender for trying to solve the problem.

 

[DoubleMIDI]

Lower frequencies that are not present in the sustain phase of a note can be present in the attack phase, which will get some punch. It also depends how much of the attack gets captured by the pickup. I think it's more with a bridge mounted pickup than with a top mounted one.

 

[drurb]

...In reality, all pickups and microphones distort the sound of acoustic instruments. In the end, it's really a fools errand, trying to hear yourself over a bandstand full of musicians who strive for recorded sounds, not acoustic sounds. God bless Leo Fender for trying to solve the problem.

I suspect we agree that a really good mic does not "distort" in the engineering sense of the word (i.e., introduce substantial nonlinearities). Any microphone placed close to a DB will not really represent well the spectral content received by listener feet away. I'm guessing that's the type of "distortion" to which you were referring.

Lower frequencies that are not present in the sustain phase of a note can be present in the attack phase, which will get some punch. It also depends how much of the attack gets captured by the pickup. I think it's more with a bridge mounted pickup than with a top mounted one.

Indeed that's true with a pickup but they are not radiated acoustically with any substantial power at all. The impulse of the attack that is radiated acoustically is, I believe, dominated by frequencies well above 50 Hz with the bass acting as a substantial high-pass filter.

 

[MR PC]

Yup, Ron Carter, Ray Brown, Eddie Gomez, ect, all mined the gold on that attack phase...fool's gold that is.