I've chosen the drivers, finished the modeling, and have built the cab. I'd like an easy to follow sketch for a passive HPF around 35 Hz. A link to an easy to understand tutorial/PDF or page is OK, too.
I tried searching around, but didn't want to take anything for granted from a HIFI standpoint. This is for a bass guitar cab, and if there's going to need to be different voltage or other valued components better suited, I'll need someone to help me out there and tell me.
It'll be a 4 ohm cab, and the excursion plot is telling me that the drivers in that design will go to their full 300 watt (combined) power rating. The curve only peaks above xmax at (and below) 30 hz. This is just as much for protection as it is for power-savings, but easy is the key. If there's a harder way, but a lower cost, sure mention it, but EASY is key here, it's my first.
I tried searching around, but didn't want to take anything for granted from a HIFI standpoint. This is for a bass guitar cab, and if there's going to need to be different voltage or other valued components better suited, I'll need someone to help me out there and tell me.
It'll be a 4 ohm cab, and the excursion plot is telling me that the drivers in that design will go to their full 300 watt (combined) power rating. The curve only peaks above xmax at (and below) 30 hz. This is just as much for protection as it is for power-savings, but easy is the key. If there's a harder way, but a lower cost, sure mention it, but EASY is key here, it's my first.
Why on earth would you want one? - it's going to reduce power, be large, heavy, and expensive - and not produce any worthwhile result.
Because the cab it's going into is a bass cab and intended for sale. I can't predict what amplifier or specific instrument (EDB, EUB, ERB) will be used. The excursion is only peaking at max power below 33Hz. At 35Hz the models have the system -12dB anyway. I'm simply eliminating information the speakers might see which wouldn't be useful, will make the amp work harder, and be bad for the speakers anyway.
Edit: Also, VERY useful for DB players with super widely voiced piezo pickups. Those piezo's go super deep, and can really be a mess without some sub bass roll-off. Most 'bass' controls on all-in-one amps have a slope that is too shallow and a start point that is too high to really serve this function (i.e., they roll off too much of the 'good' bass relative to the sub bass). Last edited: May 7, 2014
KJung, May 7, 2014
#4
The high pass in most power amps is set too high to be too much use to most bass players. Usually around 100hz, which is tailored more for people who are using a dedicated sub with a set of speakers that have mid/tweeter capacity. BurningSkies, May 7, 2014
#9
for a long while now I have heard that sometimes a HPF is useful for a bass guitar, but I don't understand much of the reasoning behind it. I'm hoping someone can explain to me why it's used, and at what frequency it should be used, particularly with reference to lower than usual tunings (B0 and possibly F#0). also bonus points for suggesting the hardware necessary to implement it.
Thanks!
An external hi pass filter CAN be useful in some cases, but not all. If you are using a PA type power amp with a preamp, most PA power amps have a hi pass filter that you can turn on. If you are using an old model or a very low end model, then an external hi pass will help control the deep low end that can suck power and, in some cases, mechanically damage your speakers at high volumes. In this case, it will help make your rig more efficient and 'safe' without noticeable changing the tone.Thanks!
Edit: Also, VERY useful for DB players with super widely voiced piezo pickups. Those piezo's go super deep, and can really be a mess without some sub bass roll-off. Most 'bass' controls on all-in-one amps have a slope that is too shallow and a start point that is too high to really serve this function (i.e., they roll off too much of the 'good' bass relative to the sub bass). Last edited: May 7, 2014
KJung, May 7, 2014
#4
The high pass in most power amps is set too high to be too much use to most bass players. Usually around 100hz, which is tailored more for people who are using a dedicated sub with a set of speakers that have mid/tweeter capacity.
#9
fdecks HPF, Part II | TalkBass.com
^^ check out the fdeck thread. The link to the "part 1" of this thread is coming up blank, but the thread is good.
Helpful in many cases, of which a cab for sale to whomever for whatever bass job would benefit from having one built into it. Most people won't even notice it, but those who do use it for extended range or DB with piezos will find it a plus.
One that could be used as an add on, for it to be put in the front of the signal chain would be best, but I'm working a prototype, so I'm wanting to A/B two kinds.
^^ check out the fdeck thread. The link to the "part 1" of this thread is coming up blank, but the thread is good.
Helpful in many cases, of which a cab for sale to whomever for whatever bass job would benefit from having one built into it. Most people won't even notice it, but those who do use it for extended range or DB with piezos will find it a plus.
One that could be used as an add on, for it to be put in the front of the signal chain would be best, but I'm working a prototype, so I'm wanting to A/B two kinds.
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Sorry, I still think it's a crazy idea - and would probably make your cab too expensive to buy, whilst offering no advantage.
Any such filtering (assuming there's any slight advantage in doing it?) should be done in the amplifier - where it would be small, cheap, light and effective.
A passive version in the speaker is going to be none of those.
But if you want to play, have a look at the calculator here:
2-Way Crossover Designer / Calculator
Is your intention to do this at line level? If so, look at the FMod threads on TB. A passive solution in the speaker cab at power amp output level is pretty much out of the question if you want anything like what the fdeck offers for slope order, and I think you'll find that at least some adjustability is highly advantageous as well.
I'm wanting an instrument level adaptor, or something small and sweet, that the user can simply insert somewhere before the power section. Plugging the instrument cable right to it; the output is the 1/4" plug for the amp. I'm open to what anyone has to say on the topic.
After a bit of digging, I'm not going to try and hard-wire one in the box. I was going to a/b two cabs, one with a speaker level built in, and one with a low-powered one in the front. So your right, this work has been done, and as mentioned; it's no good in the cab.
So on to the next part which is this: Can a decent one with the cutoff I'm looking for be wired into a plug of sorts? I'm thinking 1/4" female to 1/4" male, with all the magic bits in between, yet still not too bulky (or long) to plug into the amp.
After a bit of digging, I'm not going to try and hard-wire one in the box. I was going to a/b two cabs, one with a speaker level built in, and one with a low-powered one in the front. So your right, this work has been done, and as mentioned; it's no good in the cab.
So on to the next part which is this: Can a decent one with the cutoff I'm looking for be wired into a plug of sorts? I'm thinking 1/4" female to 1/4" male, with all the magic bits in between, yet still not too bulky (or long) to plug into the amp.
You mean between preamp and power amp or between instrument and preamp/amp?
Anyway you will not have frequencies your Bass can't produce to begin with.
How low does a 5 or 6 string Bass go?
Piezo pickups or not, it's a matter of string lowest frequency and I doubt they go *that* low anyway.
Sensibly designed Bass amps already incorporate suitable HPF anyway.
Anyway you will not have frequencies your Bass can't produce to begin with.
How low does a 5 or 6 string Bass go?
Piezo pickups or not, it's a matter of string lowest frequency and I doubt they go *that* low anyway.
Sensibly designed Bass amps already incorporate suitable HPF anyway.
Any decent performing filter will require power, as it NEEDS to be active, not passive - but as others have said there's likely to be some kind of HPF in the amp anyway, and I still see no requirement for one on a bass guitar?.
Ok, here it is.
EASY ? sure, just 2 parts 🙂
Cheap?
😕 ... it´s up to you.
Second Order (12db/octave) Two-Way Crossover
Linkwitz-Riley
High Pass Impedance: 4 Ohms
Frequency 35 Hz
C1 = 568 µF
L1 = 36 mH
You can buy Crossover rated caps at some of the usual suppliers, but you´ll have to custom wind the inductor, which will look similar to this, although much larger and heavier.
Given that the speaker is 4 ohms, it should have a DC resistance lower than, say. 0.4 ohms so as not to absorb way too much power.
Online calculators do not go that low, but for reference here´s a roughly 1 ohm DC resistance one.
Yours should be some 3X larger and heavier :
Shavano Music Online
Air Core Inductor Calculator V 1.5
Air Core Inductor specs for 35.000 mH
Using copper wire in the following wire gauges:
Wire Gauge : 10
DC Resistance : 0.92 Ohms
Inductor Height : 2.48 Inches ( 63.07 mm)<-- actually 3X as much
Inductor Radius (internal) : 4.97 Inches (126.14 mm)
Number of Turns : 310
Wire Diameter : 0.104 Inches ( 2.64 mm)
Note: to reduce resistance to an acceptable level, you´ll need to use twice as thick wire, or wind it trifilar, using 3 #10 strands.
Estimated Wire Length, Plus 10 inches : 921.0 feet ( 280.7 m)
remember you´ll need 3X that length (and weight) because you´ll need to lower resistance to an acceptable level.
AWG 10 wire weighs 31.5 lbs/1000Ft so the 3 x 921 ft needed will weigh some 2.76 * 31.5=87 lbs of copper.
You´d better mount very good wheels in your cabinet. 😱
I have taken apart plenty of bass cabs in my time and have never seen a passive HPF on any of them, which is very probably due to the immense components as mentioned before. It's simply not feasible. And think about it: why on earth would amplify a signal only to attenuate it again? That's a headroom killer, especially in the lower regions. And how much power would it dissipate?
... It's so silly someone should really build it to prove how silly it is 🙂
The fundamental of a low-B-tuned bass guitar is 30Hz, few run-of-the-mill bass cabs can reproduce this anyway.
... It's so silly someone should really build it to prove how silly it is 🙂
The fundamental of a low-B-tuned bass guitar is 30Hz, few run-of-the-mill bass cabs can reproduce this anyway.
Putting some boring Math into projects often makes them sound SO silly 😉
Of course, many Believers brush that away just by firmly sticking fingers in their ears, closing their eyes, and making burping noises with their tongues 😉
Dumb And Dumber (1994) - The Most Annoying Sound In The World - YouTube
Of course, many Believers brush that away just by firmly sticking fingers in their ears, closing their eyes, and making burping noises with their tongues 😉
Dumb And Dumber (1994) - The Most Annoying Sound In The World - YouTube
The OP mentioned ERBs (extended range basses). I have seen and played one with a fundamental below 13Hz. That opens up a pretty serious can 'o worms I'd just as soon not look into, however...
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Thanks for replies. I'm still interested in checking out a very small, active one. Once I have the circuit, I can build the widget per cab. Some people will choose to not use theirs. Some rigs could roll of closer to 40 . Some cabs may be built for someone using ERB's like discussed. Low B on a 5 string has its fundamental down there, too. I could roll it off under the B for those cabs. 5 strings aren't exactly rare these days.
If someone is going down low, whether dropping or playing an ERB, I want to give them (even at -15dB) whatever the driver can handle down there; but, nothing below what it can produce safely if the signal is present. I agree that for most players, especially electric 4 string players, it's not something that is needed. When was the last time you used your auto emergency kit? Did you buy it? You may not have used it, but it's there, and you didn't pay extra for it. Same principal here.
If someone is going down low, whether dropping or playing an ERB, I want to give them (even at -15dB) whatever the driver can handle down there; but, nothing below what it can produce safely if the signal is present. I agree that for most players, especially electric 4 string players, it's not something that is needed. When was the last time you used your auto emergency kit? Did you buy it? You may not have used it, but it's there, and you didn't pay extra for it. Same principal here.
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And what musical use has an instrument with inaudible sound?
I'd seriously question the sanity of anybody playing or building one.
Well, if you call over 90lB of stuff "a widget", I can't go against that 😉
No, neither 6 strings.
But both stop squarely at 30 Hz.
So you won't charge extra for it?
Something with an estimeted cost around U$1500?
Wow!!! you are truly generous !!!!!
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I think you missed the part where I said "ok, thanks" and agreed with the cab not being where it's going. A small instrument or line level add on to include with the cab is what I'm after.
There are these (and similar) http://www.marchandelec.com/xm1.html , but really it's got more than I'm after, and requires too much power. I'd like to have something a 9V or even better, a AAA can run. If it's around, I'll find it. I'm simply seeking direction. Maybe a couple links to check out. Shure makes a 100Hz XLR filter. What I'm is like this, but 1/4", maybe, and I make one with the desired corner.
There are these (and similar) http://www.marchandelec.com/xm1.html , but really it's got more than I'm after, and requires too much power. I'd like to have something a 9V or even better, a AAA can run. If it's around, I'll find it. I'm simply seeking direction. Maybe a couple links to check out. Shure makes a 100Hz XLR filter. What I'm is like this, but 1/4", maybe, and I make one with the desired corner.
An externally hosted image should be here but it was not working when we last tested it.
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I tend to agree with you Juan, not that it matters much. What does sanity have to do with playing music anyhow though? 😎
You can hear the harmonics just fine and the harmonic series is different from any normal bass. There's a semi-viable niche market and at least a few people are successfully gigging and recording with these things. Synth bass can also go very low, as you of course know.
Besides the passive Harrison Labs FMOD I mentioned, Rod Elliot sells an active subsonic filter board on his website. Francis Deck also has a schematic for his older design posted on his site.
Personally, I tend to prefer having the HPF right in front of the power amp, or limiter if there is one pre-power amp. One can make a reasonable case for placing it in any number of other spots in the signal chain as well though. As JMFahey said, many/most well designed amps will already have one though, and most of my cab designer friends just let the end user decide if a separate appliance is really needed for their playing situations.
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