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Double Bass Yamahiko Double Bass Pickup

#661
Ben Rolston said:
@SamuelHarris With the original jack I was basically always clipping whatever input I was using. On Felix turned ALL the way down, it still hit red, though it didn't sound like "clipping" - on the AI amp I tried it sounded like a buzzsaw

The new jack appears to have a capacitor in the housing, and allows me to get plenty of headroom. Not only is it not clipping anymore, but as a number of people have noted, with double bass pickups there can be a sweeter, more acoustic sound with a gain setting a fair bit lower than "barely not clipping".
Click to expand...
It is not so much a characteristic of the piezo pickup but the input stage of the (pre-)amp and the clipping indicator circuit.

The clipping might be shown when the RMS clips but peaks can clip much earlier than the clipping indicators shows or gets visible clear enough.

The (pre-)amp can clip if the gain control is after the first amplification stage (i.e. FET or valve). Then the first input stage can clip with a large input voltage and the gain only puts the volume of the already clipped signal down. In that case a attenuated input signal helps.

Since piezo signals deliver a very limited current (that‘s why we need the FET/valve preamps), it is better to use a capacitor-based voltage divider (piezo is one capacitor, the other one in the jack in series with the piezo) than a resistive voltage divider (which reduces the input impedance).

Usually foil capacitors are used for a good sound, the value depends on the pickup, but are probably in the nF range. Just in case one wants to make an adapter (cable) with a capacitor from hot input to hot output to experiment with.
 
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#662
Ben Rolston said:
@SamuelHarris With the original jack I was basically always clipping whatever input I was using. On Felix turned ALL the way down, it still hit red, though it didn't sound like "clipping" - on the AI amp I tried it sounded like a buzzsaw

The new jack appears to have a capacitor in the housing, and allows me to get plenty of headroom. Not only is it not clipping anymore, but as a number of people have noted, with double bass pickups there can be a sweeter, more acoustic sound with a gain setting a fair bit lower than "barely not clipping".
Click to expand...
I think this might happen when using just one side of the pickup. I do notice more gain myself that way. I generally now use both sides bridged which is probably more how the pickup was originally intended to be used.
 
#663
Using two passively coupled piezo elements the elements grab energy from its neighbor.
Piezos are not only sensors but also actors. Think about the greeting card piezo disc speakers. The same kind of piezo discs is used for the Fishman BP-100 and other similar pickups.

In my experiments with piezo disc elements as pickups, the sound of individually buffered piezo elements that are mixed after being buffered was a much better than buffering two interconnected piezo elements. They not only get mixed electrically but take some of the electrical energy to mechanically deform (just a very little bit and only temporary as long as the energy gets absorbed).

The parallel connection might help to reduce the peak voltage and that can be helpful to work with an otherwise overloaded input stage, but a capacitative attenuation and individually buffers pickups would deliver a better sound.
 
#665
Ben Rolston said:
With the original jack I was basically always clipping whatever input I was using. On Felix turned ALL the way down, it still hit red, though it didn't sound like "clipping" - on the AI amp I tried it sounded like a buzzsaw
Click to expand...

Ben, I just experienced the same issue with my Grace Felix and and
the Planet Wing piezo on my Kolstein Busetto Bass. As I recall their are internal jumpers on Channel 1 that
allow you to lower the input gain on that channel
 
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#666
Ric Vice said:
Ben, I just experienced the same issue with my Grace Felix and and
the Planet Wing piezo on my Kolstein Busetto Bass. As I recall their are internal jumpers on Channel 1 that
allow you to lower the input gain on that channel
Click to expand...

You're right, but I think mine came set on low gain default? So it's more of a gain boost. In any case, I like to blend a mic sometimes so taking over channel 1 was a no go.
 
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#667
Yeah, makes sense. I do seem to remember that when they replaced the Op Amp on the Amp Out, they reset the Channel 1 input to it's default setting
and since I use the Ehrlund I had to go inside (kinda scary in there!) and change out the jumper. Not a fun thing to do, at least for me. But I don't remember
if it was to hot or to soft.
 
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#671
Ric Vice said:
Let me know how that works, the CM4 is a incredible microphone for recording Double Bass. Inquiring minds want to know, if you get it to work live with a Grace Felix. Now that would be something wonderful.:)
Click to expand...

IMO, the CM4 is too good a mic at what it is designed to do for this to be likely to work. It could be a really nice mic for FOH reinforcement provided it was used sparingly or not at all in the monitors, but the mic is designed to pick up everything in its relatively wide polar pattern accurately, and it’s very good at that.

That also means that everything around it will bleed heavily into the signal, because it hears everything that you would hear if you put your head where it is placed. A good live mic is more likely to be a hypercardiod dynamic mic, designed to limit picking up off axis signal. Even then, reflections off the top of the bass come into play if the bass is not isolated.
 
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#672
Chris Fitzgerald said:
IMO, the CM4 is too good a mic at what it is designed to do for this to be likely to work. It could be a really nice mic for FOH reinforcement provided it was used sparingly or not at all in the monitors, but the mic is designed to pick up everything in its relatively wide polar pattern accurately, and it’s very good at that.

That also means that everything around it will bleed heavily into the signal, because it hears everything that you would hear if you put your head where it is placed. A good live mic is more likely to be a hypercardiod dynamic mic, designed to limit picking up off axis signal. Even then, reflections off the top of the bass come into play if the bass is not isolated.
Click to expand...

:) I guess the mic that's closest to the CM4 but designed for live performance, would be the Xlson that our fellow TB er Rick Wolf uses. While I'm not one to hang a microphone off the end of a Explore Audio boom clamped to my bass, it does sound pretty fantastic.
Unfortunately, that sound will cost you four times what the CM4 costs. The Remic Green that I use FOH is way easier to mount and remove but once again is four times the cost of the CM4.

Remic DB 5400 LB.png

It has it's quirks, but for me it works quite well. Just another possible option, it does not work back to an amplifier. It's for FOH
 
#674
I’ve been corresponding with Kiyohiko about a modified pickup to fit a low EUB bridge with very short feet. He has been happy to do custom work shortening the non-threaded part of the sensor shaft to get me something that fits with a threads up install. I am very impressed and after this one is sorted will likely install a stock Yamahiko on the acoustic too.

I’m not finished going through this thread in detail but it’s still been a huge resource. Many thanks to the contributors.

This is the mod Kiyohiko is doing for me. Assuming a threads up install this kind of mod should make it unnecessary to add wood to bridge feet to accommodate the length of the pickup as some have reported needing to do.

D811AB9C-123D-48BE-9BE9-08307322C1F4.jpeg
 
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#675
DoubleMIDI said:
The CM4 has a broad cardioid, something between an omni and a cardioid. So it does pic up sound from behind, but a little bit softer than from the front.
Should work well close to the top, but I haven’t tried it yet. I almost always play EUB with my Latino music group now.
Click to expand...

I've connected it to the Grace Felix through one of my powered MAS cabinets. As I recall (it's been some time since I tried that experiment) it was susceptible to feed back. That said, so are most microphones, into a cabinet at ground level, in close proximity, to the bass and microphone.
 

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