Double Bass Dealing with sub lows

[dukeorock]

Been wanting to hear from people much smarter than myself on this topic...

I like a pretty tubby sound and one of my bands is quite loud. I've seen and heard about products like the fDeck or the Thumpinater(?)...basically HPF's.

I keep a DBX 2031 graphic eq in my rack to deal with different rooms quickly...

My question is, at what frequency does 'real' usable low end start? I've started doing a taper from about 40hz slightly down, 32hz slightly further down, 25 a little further down, etc. Does this serve the same purpose? Sometimes live, I feel like my lows are clipping a bit, even though it doesn't sound too bassy to me a bit.

Currently using a Genz ShuttleMax 12.0 with a Genz Uber 410 and sometimes an Uber 212 on top of that for the loud gigs. For the smaller gigs, I have ordered an AudioKenesis TC 115AF which should be here in a week

Would love any advice on this subject.

 

[agedhorse]

It depends entirely on the source and the ability to amplify/reproduce it.

With an average 4 string EB, somewhere in the low 40's is probably a good (as in practical) target for the fundamental but you must consider that the second and third harmonics can be a large as the fundamental so while there will be a difference in a system that can not reproduce quite as low, it may not be as important as you might initially think. The real world limitations are generally in the speakers rather than the amp.

You need to be careful when using a 1/3 octave eq on a bass signal because the filters might be a bit narrow or might combine (in response) less than favorably, or not quite as you might expect. This is especially true when executing large boost and cuts.

To extend the LF response on your Max, try using the LF Boost (actually an extend circuit) as that amplitude & phase response of this filter is probably more intuitive and useful in tailoring low end extension. Be sure your cabinets can handle the power and are large enough to allow for adequate response if you use a lot of extension (general comment for others who may be reading this)

Hope this helps.

 

[Ric Vice]

Been wanting to hear from people much smarter than myself on this topic...

I like a pretty tubby sound and one of my bands is quite loud. I've seen and heard about products like the fDeck or the Thumpinater(?)...basically HPF's.


Currently using a Genz ShuttleMax 12.0 with a Genz Uber 410 and sometimes an Uber 212 on top of that for the loud gigs. For the smaller gigs, I have ordered an AudioKenesis TC 115AF which should be here in a week

Dude O Rock,
Although their will be times when FDeck's HPF Pre will be a necessity, it's my court of last resort. The Thunderchild has such great frequency response and even coverage, and smooth transition between the horn and driver that you're going to hear you're instrument better.
You can't beat the HPF/Pre when you need one though, especially at the price. He's also working on a new one, but it's in the development stage.

Ric

 

[iiipopes]

"Real" usable low end also is a function of the room. I find my fdeck indispensible for gigging to tailor to the room as well as generally eliminating rumble. However, in years past, there are rooms I've played in that have particular resonances that a tight notch filter would be nice. But this was more of a problem when I played heavy slab gigs. Then, the sound man was usually good enough to have eq'd the room, and I went through the system, so it wasn't an issue.

"Real" usable low end can be as high as the 98 Hz baritone vocal G in a small room, or as low as the 8.18 Hz tone produced by the pedal 64' reed stop on the famous pipe organ in Sydney, Australia Town Hall.

 

[dukeorock]

You need to be careful when using a 1/3 octave eq on a bass signal because the filters might be a bit narrow or might combine (in response) less than favorably, or not quite as you might expect. This is especially true when executing large boost and cuts.

To extend the LF response on your Max, try using the LF Boost (actually an extend circuit) as that amplitude & phase response of this filter is probably more intuitive and useful in tailoring low end extension. Be sure your cabinets can handle the power and are large enough to allow for adequate response if you use a lot of extension (general comment for others who may be reading this)

Hope this helps.

It does, thanks! I use the LF boost for sure, and I'm pretty sure you know my cabs can handle it The Uber 410 is my favorite 410 I've ever used, and I've used more than a couple As for the graphic, I usually start soundcheck with it more or less flat, start by dialing the amp in, then when people get into the room, the sound changes onstage for me, so I have the graph if I need it for a quick grab of whatever the problem frequency appears to be...I run it thru the FET channels FX loop, which seems to sound best.

 

[dukeorock]

"Real" usable low end can be as high as the 98 Hz baritone vocal G in a small room, or as low as the 8.18 Hz tone produced by the pedal 64' reed stop on the famous pipe organ in Sydney, Australia Town Hall.

I understand that it isn't always the same...just curious if there is a general rule of thumb...I don't want to be eating up all of my amps headroom with frequencies no one is actually hearing, and only cause stress to the speakers with no audible benefit

 

[drurb]

...but you must consider that the second and third harmonics can be a large as the fundamental...

...but only because something is limiting the power of the fundamental.

 

[agedhorse]

...but only because something is limiting the power of the fundamental.

Not always true.

Look at the profile of the waveform of a bass guitar note and especially lower notes are full of 2nd and 3rd harmonics, and the sum of the harmonics can easily equal or exceed the fundamental. This is the nature of the generation of a plucked string's periodic motion, location of pickup on the string, etc.

I recall first learning of this important concept probably 30 years ago from Bartolini, and then again when I was developing some acosutic bass pickups a few years later. It's a large part of what makes one instument sound different from another and why all instruments sound different than a sine wave generator.

Here's a good overview:
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[fdeck]

I remember that article. In fact my speaker modeling program has a function that applies a realistic bass waveform to the cone excursion and port air speed computations. It would be interested to see how a DB pickup signal compares.

But then the electric players often plug into amps with "scooped" voicing that could bump up the fundamental by a fair amount.

 

[drurb]

Not always true.

Look at the profile of the waveform of a bass guitar note and especially lower notes are full of 2nd and 3rd harmonics, and the sum of the harmonics can easily equal or exceed the fundamental.

I recall first learning of this important concept probably 30 years ago from Bartolini, and then again when I was developing some acosutic bass pickups a few years later. It's a large part of what makes one instument sound different from another and why all instruments sound different than a sine wave generator.

Yes, you are quite correct. I was referring to the physics of pure vibrating strings and should not have given so terse a response.

The sum of the power of the harmonics surely can exceed the power of the fundamental. Now, the power spectrum you reference does show that the second and third harmonics, each have more power than the fundamental. That is decidedly not part of the "nature of the generation of a plucked string's periodic motion" but certainly is related to details regarding the pickup transducing that vibration. The plot in question was generated by playing the bass through electronics. That includes the pickups and the mechanical properties of the instrument. Those are limiting the power of the fundamental, in the sense I meant. If you were to measure the power spectrum of a vibrating string in isolation, then you wouldn't see that spectral profile at all.

You are, however, quite correct in the practical sense. If you measure the spectral profile of the acoustic waveform of the double bass, as Olsen did (see below), indeed, you find that the power of the second and third harmonics each can exceed that of the fundamental. In that case, it is the mechano-acoustic properties that are limiting the power of the fundamental.

So, what I'm saying is that, considering the entire instrument and the limitations it imposes, which, after all is all that really matters, you are quite correct, your point is well taken, and people should be aware of it!

See page 217 here which illustrates your point rather explicitly. I've posted this here before.

Believe me, I understand the role of the spectral profile in giving instruments their unique perceived sound and character. Actually, what is also of crucial importance in identifying an instrument is the temporal attack and decay profile. In fact, if you apply the temporal profile of one instrument to the long-term spectral profile of another, you can have people identify the sound as the instrument associated with the temporal envelope.

 

[iiipopes]

Everybody is also forgetting the Tartini, also called difference tones, effect: the difference tones from the harmonics, especially the 2nd and 3rd harmonics together, reinforcing the fundamental. If you have good overtone development, out front you will get fundamental even though the source may be somewhat rolled off by the amplifier and/or speaker.

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In the summer of 1984 I was studying legal history and international law at Cambridge. I sang in the Great St. Mary's choir for the summer. The last Sunday I was there we all went up to sing Evensong for the Bishop of Ely at Ely Cathedral. The choir was small, and I believe only three of us went, possibly only another gentleman or two. We had a tenor and a bass as well as yours truly on baritone. One of the service pieces, in the key of G, of course, had as its final chord the bass on bottom line G, the tenor on 4th space G, and yours truly on the midline D. We locked. The difference tone sub octave G absolutely rolled up and down the nave, as prominent as if we had another singer or instrumentalist actually playing that note. It's all the more notable since unlike most gothic cathedrals which have stone vaulting, Ely has wood vaulting, which does tend to damp the resonances. We all looked at each other with wide eyes, as none of us, individually, had ever had that wonderful experience of "filling up" an entire cathedral, simply by being in tone and in tune, but not loud.

 

[agedhorse]

Note that I am trying to dispel the myth that a bass's note is a single frequency like many simplistic articles and explanations often suggest. I think that the average TB forumite (read as gearhead) is beyond the simplistic answer and can benefit from a more in depth discussion of... say what makes one instrument sound so much different from another even though both look the same on the surface.

Just the difference between round wound and flat strings changes greatly the harmonic profile. It's not something that can be done with simple eq because you can't proportionally alter just the broad-band harmonic ratio.

 

[dukeorock]

I was just trying to see if I need to slide down some of the very lowest frequencies on my DBX 2031, if they can't really be heard and are just eating up headroom

 

[drurb]

Everybody is also forgetting the Tartini, also called difference tones, effect: the difference tones from the harmonics, especially the 2nd and 3rd harmonics together, reinforcing the fundamental. If you have good overtone development, out front you will get fundamental even though the source may be somewhat rolled off by the amplifier and/or speaker.

Not everybody is forgetting them. You are talking about distortion products, the most common of which is typically 2f1​-f2​ in non-linear syetems. Actually, in the context of this discussion, the distortion products don't play much of a role at all.

 

[Jake deVilliers]

I was just trying to see if I need to slide down some of the very lowest frequencies on my DBX 2031, if they can't really be heard and are just eating up headroom

Yeah, but you've initiated an interesting discussion!

The short answer is 'Yes.' That's what the FDeck Pre does best, tidy up your bottom end with its sweepable high pass filter. Try it, you'll like it.

 

[agedhorse]

Excellent topic, and one that could take hundreds of pages to discuss and explore. It's WAY more complicated than it appears on the surface. It's at the fundamental (no pun intended) core of why stringed instruments sound as they do.

 

[iiipopes]

Not everybody is forgetting them. You are talking about distortion products, the most common of which is typically 2f1​-f2​ in non-linear syetems. Actually, in the context of this discussion, the distortion products don't play much of a role at all.

It's not distortion. It's the hetrodyning product of the overtones. Go read Hemholz and Tartini.

 

[drurb]

It's not distortion. It's the hetrodyning product of the overtones. Go read Hemholz and Tartini.

It's Helmholtz and, yes, they are distortion products resulting from the nonlinerarities of the ear and/or system (instrument). I dare say I'm rather familiar with Helmholtz's work, I'm guessing, far more familiar than you are. Look up the definitions of Tartini tones, heterodyning, etc. You'll see the words "nonlinearity" and "distortion." Those are what distortion products are. They are called that because the nonlinearities of the system are such that the spectrum at the output contains components that did not exist at the input. So, it's not I who should go back and read more.

Here's an example.

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