This describes perfectly how a bass horn sounds.
The sound character is strikingly noticeable in outdoor venues.
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cabinet frequency response
- Thread starter bearjew
- Start date
The sound character is strikingly noticeable in outdoor venues.
So many of the arguments on this thread depend on certain musical styles.
For instance, if you're in a top-40 cover band, you'd have to be loopy to be lugging around a stack of massive cabs, tuned for true 20-30Hz performance at club levels. Almost none of the music you're playing was recorded with that kind of low end in it, FOH isn't trained or equipped to deal with it, and you're virtually guaranteed that no-one in the audience is used to hearing real sub-bass anyway. Roll off everything below 50Hz, give 'em nice tight midbass until they start to shake their behinds, and everyone will be happy.
But not everybody plays in a rock band!
When I first got into 5-string basses, I went on a quest for the perfect low B, and at one point, I built a cab according to a 6th order Thiele alignment. It needed an external processor to get there, but it was theoretically flat down to 30Hz. I had to build my own preamp as well, because I couldn't find a bass head that didn't have a built-in rolloff.
The cab didn't play very loud, and it was a royal pain to transport. Also, the fundamental still wasn't produced at an equal level to the second harmonic, because my basses weren't flat down to that frequency.
Regardless, there was a noticeable and pleasurable difference when you heard (and felt) the actual fundamental at the level that it was coming off the bass. I was playing a lot of quiet acoustic music at the time, and it sounded GREAT in that context.
Contrary to TB myth, it didn't sound muddy at all. In fact, because the cab didn't have the usual midbass hump, it sounded surprisingly articulate. It didn't cause problems in bad halls, and I got lots of compliments for the way my tone complemented acoustic piano and guitar. Doubling the left hand of a good pianist on a concert grand, was particularly sweet.
IME, problems with interference are actually far more likely to happen in the midbass region, where hall acoustics and FOH tuning conflict with regular bass cabs that have a big bump in the low mids, downtuned guitars, undisciplined keyboard players, and bad drum mixes.
For instance, if you're in a top-40 cover band, you'd have to be loopy to be lugging around a stack of massive cabs, tuned for true 20-30Hz performance at club levels. Almost none of the music you're playing was recorded with that kind of low end in it, FOH isn't trained or equipped to deal with it, and you're virtually guaranteed that no-one in the audience is used to hearing real sub-bass anyway. Roll off everything below 50Hz, give 'em nice tight midbass until they start to shake their behinds, and everyone will be happy.
But not everybody plays in a rock band!
When I first got into 5-string basses, I went on a quest for the perfect low B, and at one point, I built a cab according to a 6th order Thiele alignment. It needed an external processor to get there, but it was theoretically flat down to 30Hz. I had to build my own preamp as well, because I couldn't find a bass head that didn't have a built-in rolloff.
The cab didn't play very loud, and it was a royal pain to transport. Also, the fundamental still wasn't produced at an equal level to the second harmonic, because my basses weren't flat down to that frequency.
Regardless, there was a noticeable and pleasurable difference when you heard (and felt) the actual fundamental at the level that it was coming off the bass. I was playing a lot of quiet acoustic music at the time, and it sounded GREAT in that context.
Contrary to TB myth, it didn't sound muddy at all. In fact, because the cab didn't have the usual midbass hump, it sounded surprisingly articulate. It didn't cause problems in bad halls, and I got lots of compliments for the way my tone complemented acoustic piano and guitar. Doubling the left hand of a good pianist on a concert grand, was particularly sweet.
IME, problems with interference are actually far more likely to happen in the midbass region, where hall acoustics and FOH tuning conflict with regular bass cabs that have a big bump in the low mids, downtuned guitars, undisciplined keyboard players, and bad drum mixes.
Yeah---unloaded means that below the tuning frequency in a ported cab that the compliance or "spring" or air isn't there. The compliance of the surround and the power of the motor (magnet and coil) aren't enough to control cone motion. So the cone essentially flaps around wildly. Like it's not in an enclosure.
So there is no control in the starting and stopping of the notes in this range. Now as we've said---these fundamentals are pretty cool but the sound of them is subtle. Here's the important part---the second harmonic--or octave above is typically louder than the fundamental at this point. So---the second harmonics above the fundamental also have the overhang of a speaker flapping wildly. You get a big "woof" without much definition that doesn't stop and hangs way too long. That's why people think that the uber lows muddy up the live sound. Uber lows aren't muddy at all---it's the octave above (second harmonic---I was mistakenly calling it the first harmonic--I looked it up) and to a lesser degree the harmonics above which are also displaying the lack of control.
That's why people think that their B strings sound tighter when a HPF is applied.That lack of control that exhibits its behavior in the harmonics in the "meat and potatoes" range is gone because the fundamentals in the unloaded range are gone.
In the uber lows it's the second harmonic (octave) that we key off of for pitch definition and pulse. I'm not saying that the fundamental isn't super cool---it is if you can reproduce it.
But that's why guys use the HPF's and say how their B strings got "tighter and with better definition" because the cone is now controlled and the second harmonic---which is louder and arguably more functional than the fundamental---is now controlled without overhang.
So there is no control in the starting and stopping of the notes in this range. Now as we've said---these fundamentals are pretty cool but the sound of them is subtle. Here's the important part---the second harmonic--or octave above is typically louder than the fundamental at this point. So---the second harmonics above the fundamental also have the overhang of a speaker flapping wildly. You get a big "woof" without much definition that doesn't stop and hangs way too long. That's why people think that the uber lows muddy up the live sound. Uber lows aren't muddy at all---it's the octave above (second harmonic---I was mistakenly calling it the first harmonic--I looked it up) and to a lesser degree the harmonics above which are also displaying the lack of control.
That's why people think that their B strings sound tighter when a HPF is applied.That lack of control that exhibits its behavior in the harmonics in the "meat and potatoes" range is gone because the fundamentals in the unloaded range are gone.
In the uber lows it's the second harmonic (octave) that we key off of for pitch definition and pulse. I'm not saying that the fundamental isn't super cool---it is if you can reproduce it.
But that's why guys use the HPF's and say how their B strings got "tighter and with better definition" because the cone is now controlled and the second harmonic---which is louder and arguably more functional than the fundamental---is now controlled without overhang.
Another important thing that Ken posted---Even if you can get those lows---it's going to take a lot of power and cone area to have it the same volume as without. That's why people notice that (especially when using a 5 stringer) that they can go noticeably louder when using a HPF without farting out---the farting out---if from the B string--is likely an unloaded driver.
Greenboy--who designs cabs known for their killer low end recommends the HPF with his cabs---he very well understands these principles.
Greenboy--who designs cabs known for their killer low end recommends the HPF with his cabs---he very well understands these principles.
When the cone unloads like that it affects everything coming out of it it would seem, the upper harmonics as well. Afterall, they're all coming from the same cone (in a typical one-way bass cab) and that cone is out there flapping in the wind.
Raising the tuning can bring up the midbass response and give it the boom that makes it sound louder/more impressive than a competitors product sitting next to it at the store. Then out on a real gig, that ends up working against you and the other, less "ballsy" cab may've been the better choice, even though it may not have sounded as impressive on the sales floor.
Raising the tuning can bring up the midbass response and give it the boom that makes it sound louder/more impressive than a competitors product sitting next to it at the store. Then out on a real gig, that ends up working against you and the other, less "ballsy" cab may've been the better choice, even though it may not have sounded as impressive on the sales floor.
A further complication arises from Xmax being exceeded. When this occurs the number of voice coil windings (or the length of wire immersed in the field within the gap) decreases on both positive and negative peaks. Motor strength (BL) then decreases. Lower BL results in higher Qes and higher Qts. Depending on the small signal Qts and the design alignment, You could then have a potentially gross misalignment. For a cab designed with a near maximally flat alignment, the higher Qts alignment (from being overdriven) will have a strong peak in the 80-120 Hz range. This peak covers a critically wide range for the bass guitar, crosses 0db in the 60-80 Hz range and comes back down around 200Hz. This accentuates the second and third harmonics of the deeper notes and the tonic of higher ones. Interestingly, starting with an over-damped driver (like Qts below 0.25) and alignment (tuned below maximally flat Fb) can result in a more normal, non-peaked alignment under overdrive conditions (when Xmax is exceeded). The cab appears to 'open up' at higher drive levels.
acmebass
Commercial User
acmebass
Commercial User
I don't "rail" against anybody," thank you, and I can speak for myself.
My words were to the effect that all matters of taste are legitimate, and it's all good.
I don't have a problem with dogma, though. If I've said anything that makes you feel "railed against," it probably has to do with that.
Thanks,
Andy
Fabulous point. That's a much clearer and concise explanation of the mechanics that are occurring. That accentuation in the 80 to 120hz range---THAT'S what we're hearing when we say that when we try to get fundamental in the B string our sound gets muddy and loads up the stage. That's also why Andy points out in an earlier post that it's probably wiser going with a huge sealed box to accomplish this.
I'm not a speaker designer---just a serious tinkerer since I was a kid. I build speakers based on other people's smarts. I would always tune my boxes lower---looking more like a sealed box curve. As I got to learn why I liked that it was because the driver unloading occurred at a lower frequency. Of course it also meant a gentle slope that needed to be eq'd up. I'd love to hear Andy chime in---he really knows his stuff---I assume that he's using similar tuning---more emulating a sealed box curve but with greater efficiency. And I know he's using proprietary drivers which I assume he can get to offset the inevitable slope drop.
When I got Dukes Thunderchild 12 I found that I preferred the response with one port plug installed. This again dropped the tuning and more emulated a sealed box. I guess that's the sound and response I like. It did require a bit of a bass boost and I assume I sacrificed some efficiency.
acmebass
Commercial User
I like to see an HPF on mine in a lot of cases as well, but I recommend a low frequency for it- 35 or lower. No reason to send stuff below "B" through the thing. It just wastes power.
Thanks,
Andy
Yeah--on fellow tb'er Fdeck's HPF the lowest setiing (24db/octave) is 35hz. Another point--piezo pickups are notorious for very loud subsonic garbage---but electric bass also can have some subsonic junk going on.
svtb15
Inactive
- Mar 22, 2004
- 13,004
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- Disclosures
- I play it all. Whatever works for the gig. Q+
I just found this on my FB page links
If this cab really does 32Hz for its size.. that is a pretty wide response.. No?
http://www.formfactoraudio.com/1bis15-single-15-bass-cabinet/
If this cab really does 32Hz for its size.. that is a pretty wide response.. No?
http://www.formfactoraudio.com/1bis15-single-15-bass-cabinet/
Only if it does 32 Hz At the -3db point or better. If it does 32 Hz at -10db or worse, not all that special.
What is typically used by cab manufacturers is a -10db point. That's about as useful as mammaries on a bull. Andy states -3db and -6db points---now that's useful.
