Dumb frequency questions.

[fretmeister]

If I'm listening to a particular bass sound and I don't have a 'scope how can I tell the frequency range of the tone.

For example - Marcus Miller's tone has a lot of crisp high end, and his signature cabs have a range up to 20Khz

But - Steve Harris also has quite a lot of high end, in a very different tone, using old style 12 inch cones that I can't imagine get anywhere near 20Khz.

 

So what range is actually needed? 

At what frequency is the highest crisp-ist most percussive part of Miller's tone?

At what point would that disappear in a cab that doesn't go as high?

 

[itu]

I measured a pair of splittable humbuckers in an LCR measuring unit. I think it cost something like £10 000, so the results should be reasonable. The coils should give this kind of results from the theory point of view, too.

The exact numbers are elsewhere, but barely nothing was coming out after few kHz. When the unit reached 5 or 6 kHz, nothing was coming out. I do not remember the -3 dB limit, but it came earlier. I try to find the numbers and you will see that 20 kHz is a joke with a coil-magnet-system. Piezo or optical system can go higher, but they need good buffering.

If the coil-magnet pickup is done with very low impedance (and very low output), the range can be extended somewhat. This kind of system needs always a good preamp.

[fretmeister]

26 minutes ago, itu said:

I measured a pair of splittable humbuckers in an LCR measuring unit. I think it cost something like £10 000, so the results should be reasonable. The coils should give this kind of results from the theory point of view, too.

The exact numbers are elsewhere, but barely nothing was coming out after few kHz. When the unit reached 5 or 6 kHz, nothing was coming out. I do not remember the -3 dB limit, but it came earlier. I try to find the numbers and you will see that 20 kHz is a joke with a coil-magnet-system. Piezo or optical system can go higher, but they need good buffering.

If the coil-magnet pickup is done with very low impedance (and very low output), the range can be extended somewhat. This kind of system needs always a good preamp.

If that is the case then why does a variable tweeter still have an audible effect when turned off? Does that mean the tweeter's range starts below 5 or 6Khz and turning it off is only removing that bit?

[itu]

Here are some results. I used these frequencies while measuring coils (five of them; the dummy coil of the D5E was also quite similar in performance) of the two pickups: 50, 100, 200, 500, 1k, 2k, 3k, 5k, 6k, 7k, 10kHz. Both were splittable humbuckers, namely bartolini C5C and D5E (from a 1991 Modulus Graphite Quantum 5 SPi Custom). The pickups were desoldered from other electronics (pots, switches & the TBT preamp - the one with external capacitors).

One interesting detail was that the pickups had a 3 dB difference (neck vs. bridge), but the coils within one pickup produced exactly similar curves from 50 Hz to 3 kHz.

The response curves were as expected. Between 50 Hz and 1 kHz the curve stayed within 6 dB, but then the curve changed to a slope. In the 1 - 3 kHz area the drop was 9 dB, and 3 - 6 kHz 6 - 8 dB depending on the coil. This means that the total drop from 50 Hz to 6 kHz is around 20 dB. To get an idea of this amount, it's like the 50 Hz would be 100 % and 6 kHz 10 %. It is not very much, although ears are very sensitive at around 1 kHz. This is the area that gets hurt easily, not the 10 kHz area.

[The frequencies around 1 kHz are very important because of the speech recognition (Say what!?). Play hard, use ear plugs.]

If you want some ordinary coil-magnet pickup to produce something serious in the frequency area of 3 - 20 kHz, prepare to be able to amplify the signal a lot! 12 - 18 dB of amplification in a bass preamp is not so uncommon, new strings help, too. I heard a rumour, that Mr. Miller changes the strings in studio after 3 hours of playing. True or not, that could explain one part of his sound.

Edited June 29, 2020 by itu

[Bill Fitzmaurice]

4 hours ago, fretmeister said:

For example - Marcus Miller's tone has a lot of crisp high end, and his signature cabs have a range up to 20Khz

Possibly, but there's very little bass content above 10kHz even with single coils, and what's above 15kHz you probably can't hear anyway unless you're a teenager.

Quote

Does that mean the tweeter's range starts below 5 or 6Khz and turning it off is only removing that bit?

Most start around 3.5-4kHz. I run mine down to at least 2.5kHz, because ten and twelve inch woofers don't have useful off-axis response above that.

[Jus Lukin]

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Edited March 6, 2022 by Jus Lukin

[Jus Lukin]

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Edited March 6, 2022 by Jus Lukin

[fretmeister]

This is useful.

I’m thinking about a new cab, and looking at specs. And whether I want a HF driver in it or not.

[itu]

I would opt for the tweeter. When it is there, you can use the pad to turn it down. If not, you are not able to dial in any more of it. And price is always one part of the equation.

[la bam]

With Marcus' sound I'd also check out his bass. The Fender or the Sire v7s.

I'm one of those finger style players who somehow seem to remove all the potential zing and character from a bass when playing, but I have a marcus designed v7 and honestly it is so full of bright zing even I sound lively.