# Is a Piezo Only Metal Tone Possible?



## cgmorrison (Jul 27, 2021)

I'm planning a build for a 6 string fretless headless bass. I'm really digging the super clean look of piezo only basses. I would ideally like to get the cliched clanky metal bass tone. Am I going to be disappointed without magnetic pups or can a decent metal tone still be achieved? I've tried searching all over various forums and videos, but everything I find has nothing to do with metal.


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## odibrom (Jul 27, 2021)

cgmorrison said:


> I'm planning a build for a 6 string fretless headless bass. I'm really digging the super clean look of piezo only basses. I would ideally like to get the cliched clanky metal bass tone. Am I going to be disappointed without magnetic pups or can a decent metal tone still be achieved? I've tried searching all over various forums and videos, but everything I find has nothing to do with metal.



Can you mod or access a bass loaded with piezos. Try it out first?


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## Adieu (Jul 27, 2021)

If you want clean look, just use a pup with a wood cover

Hell just glue a suitable veneer on an EMG or Duncan


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## cgmorrison (Jul 27, 2021)

I have an old 4 string that was given to me and I've never played that could be modded. From my reading I understand I would need a proper preamp along with the piezos to get a usable sound. I might go that route, but was looking for feedback from someone who knows before dropping money on an experiment.


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## cgmorrison (Jul 27, 2021)

The wooden pup cover is what I'll do if Piezo only isn't a viable option. I still just love the look of nothing under the strings.


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## Crungy (Jul 27, 2021)

I'm not sure if you'd get much of the clank, with no frets at the end of the neck for the strings to hit. It seems the frequency response would be pretty different as well, with way more top end that you'd probably want to eq out. Hard to say without trying it. 

Is your build something you could do with no magnetic pickups, then add pickups later if you're unhappy with the piezo only tone?


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## c7spheres (Jul 27, 2021)

I'll throw this in the mix in case you never knew of them. Prerty neat idea, but they have bass' with only the bridge-saddle area pickup, so a piezo rather than light beams seem it'd work and whethere it sounds good would be subjective. 

https://www.willcoxguitars.com/lightwave-optical-pickup-system/


- Also there's the Ibanez Ergodyne's with piezo, but still mag pickup too, but maybe if you can find one to try out you'd know if you like it.


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## Crungy (Jul 27, 2021)

I forgot about Lightwave! Never played one but they're interesting.


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## odibrom (Jul 27, 2021)

Ok, I'm back to the thread out of curiosity and because I re-read the initial post to understand that the bass to be is to be fretless...

So, with that in mind I have a few more words than just those above.

HELL YEAH!, metal needs more fretless basses, different tones to get different dynamics - so, this is just for the fretless metal bass. There are lots of good examples of fretless basses in metal.
Piezos and metal also works pretty well (in my opinion). Personally, I've been in the piezo loaded guitars since about 2002, and I've grown to understand them as a different timbre/tone to play with, even with distortion over them, not just for clean playing. So, this is a GO FORWARD with the idea of a PIEZO ONLY bass.
Personally, I've been modding my guitars to get the most tonal options possible out of them, so piezo only would not be my game, but your idea of having nothing under the strings is interesting. As far as bass tones go, I'm out of that loop long ago, but comparing piezo and magnetic tones, I can say that piezos sound "rawer" with a broader frequency range, bass and treble freqs will sound louder at the extremes of the spectrum.

Also, note that not all piezos are the same, not all piezos need a preamp (although I strongly suggest to get one to further shape your tone). My experience started with LR Baggs piezos for electric guitars, then Graphtech's, both with their own preamps. They sound different, although closer to each other than to magnetic pickups. In order to further shape your metal tone, you should probably also work with an EQ pedal such as the Source Audio's EQ2, or any other 10 band graphic EQ. Those can really help you shaping the fretless tone with just the piezos.

So, in conclusion, YES, GO FOR IT! Remember you can always rout a cavity for magnetic pickups if you find you'll miss them...


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## cgmorrison (Jul 28, 2021)

I looked into the lightwaves. The only reason I'm throwing that idea out is because I'm trying to go for something similar to the Ritter Roya concept. I'm not a fan of the body shape, but the strings passing through the body/head on both ends is appealing to me. I'm going for a super simple/clean look. But as said, pup cavities can be routed later. 

Beyond Creation's fretless bass sound is phenomenal to me. Even without the "clank" I'd still be going for the tight low end with distortion on the highs.


I figured I'd have to heavily EQ it. I'll be playing through my Helix. I don't play much other than metal. Usually, I'll only tweak the gain and IRs between patches to help my tone better match whatever I'm playing along with. Basically variations of the same patch, so I'm not too worried about having a wide variety of tonal options.

Would you still suggest having a preamp if I'm not going to constantly be tweaking my tone, or would EQing through the Helix suffice? I guess my biggest concern is that I'd be trying to force them to get a tone they can't do. It might come down to adding piezos to the junker I have and see how that works.


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## Hexer (Jul 28, 2021)

I have an Esh Stinger I 5-string that has dual active EMG singlecoils and a piezo bridge.

In my experience the piezos by themselves sound somewhat "thinner", more focused on mids and highs than lows and, as @odibrom said, more "raw" in a way. 

Personally, I like to use the piezos TOGETHER with the magnetic pickups. Blended together they don't change the sound a whole lot but they do give it a bit of that raw texture in the midrange and if I use overdrive/distortion, it gives that more to work with, too (I think the difference in sound is more obvious with overdrive than without).

My bass does have frets though so can't really comment on the combination of piezos and fretless...
As other have said though: There are several good examples of fretless bass in metal, even clanky sounding ones (check out some Steve DiGiorgio videos, he plays a fretless even in Testament). The ones I've seen used magnetic pickups but I don't see why you couldn't do it with piezos. They would sound somewhat different of course but yea...

So bottom line: you might have to adjust EQs differently either on your rig or the bass/preamp itself but in general, I think it should be pretty practical.


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## bostjan (Jul 28, 2021)

Yes, piezos lack the big feeling of the low end on a bass. I've tried playing with preamp settings, and I'm sure you can get there, but the amount of pain in the ass that you'd have to go through to get a useable tone makes me thing that it'd be impossible to get a really good tone, if you know what I mean.

I've only once demo'd the lightwave pickups, and they sounded a lot like piezos to me, but, in theory, they should be able to transmit low end better.

I played fretless bass (with Bartolonis) for almost ten years- including metal. I thought it was rad. But you definitely don't get as metallic an attack when you strike a note, no matter how hard you dig into it. That was never part of my sound, but I know there are other guys who rely on that tone to cut through better. It sort of depends on balancing the tone you want with the available sonic real estate left over after the band's guitars, drums, and cymbals stake their claims.


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## cgmorrison (Jul 28, 2021)

So Odibrom is saying the highs and lows will be louder and bostjan is saying they lack a big feeling low end. Is this a result of using different brands of piezos or am I not understanding something? 

If I end up adding a magnetic pickup, would the action on a fretless be low enough that a pickup hidden under a fretboard that extends all the way to the bridge would sound good? Hopefully that makes sense.


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## bostjan (Jul 28, 2021)

cgmorrison said:


> So Odibrom is saying the highs and lows will be louder and bostjan is saying they lack a big feeling low end. Is this a result of using different brands of piezos or am I not understanding something?
> 
> If I end up adding a magnetic pickup, would the action on a fretless be low enough that a pickup hidden under a fretboard that extends all the way to the bridge would sound good? Hopefully that makes sense.


There are in fact all sorts of piezoelectric pickups.

Pretty much all of the elements are small (to fit under the saddles) and made of lead zirconate-titanate (PZT). The bulk material tends to have a peak sensitivity above 100 kHz, which is higher than human hearing, but the sensitivity in the frequency domain is not increasing linearly up to that point, there are little local peaks and it's generally sort of a gradual bell curve up to that point. The sensitivity around 40 Hz (low E) is not so good, but not too bad, either, I suppose, but, often there is a little slump in sensitivity a little above that frequency, which can scoop out some of the low mids of the tone just by the nature of the pickup. That, to my ears, results in a sort of unpleasant tone for bass, since those low mids help bolster the output of the bass where it's most needed. Depending on the size of the piezo element, though, this could probably be engineered around, but it'd take a little bit of experimenting and might not even work very well without using some sort of nontraditional material as a pickup element (something with better low-frequency sensitivity). Magnetic pickups are generally less attenuated than piezo pickups at lower frequencies, although they do suffer from their own limitations.

The other drawback, versus magnetic pickups, is that, even though the pickup material attenuates bass frequencies, there is no isolation from external noise, so piezoelectric pickups tend to pick up more unwanted noise from jostling around or resonance from the instrument's body or whatever, even if just a little - magnetic pickups don't do that at all, since they only pickup vibration from the strings or other ferromagnetic substances.

The lightwave pickups should be focused optically right on the strings, so there should, in theory, be less noise interference than piezoelectric pickups, and they, in theory, should also be better at picking out low frequency oscillations. In fact, they ought to be fantastic at it. I was intrigued by the idea of them, but, after trying them out for the first time, probably 15ish years ago, I thought they were kind of obtrusive, expensive, and although I liked the sound, it didn't inspire me to install them on my own guitars and basses.

I've made my own piezo pickups and played around with them quite a bit, I think they are great when the convenience is necessary or when there is another option to blend tones, and I recommend playing around with the idea. But I'm not so sure you'd be happy with having them as your only option if you are going for a good metal bass tone. You can get a bag of 3/4" piezo elements on amazon. I'd say you should try one of those with 2-sided tape, attached under a bridge of an old bass, then either solder or clip the leads to your cable, and see if you can get in the ballpark of the tone you want with that. If you get close, you could certainly improve on it, but if you tweak the EQ and can't get anything other than an anemic brittle mess, I'd say that the idea would likely not work out to the end that you desire.


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## odibrom (Jul 28, 2021)

cgmorrison said:


> So Odibrom is saying the highs and lows will be louder and bostjan is saying they lack a big feeling low end. Is this a result of using different brands of piezos or am I not understanding something?
> 
> If I end up adding a magnetic pickup, would the action on a fretless be low enough that a pickup hidden under a fretboard that extends all the way to the bridge would sound good? Hopefully that makes sense.



Allow me to remember that I have no direct experience with piezos on BASS guitars. Not all piezos sound the same and that is due to either the piezo-electric element that produces signal as well as the material it is encapsulated in and/or the electronic add-ons that process the captured signal.

My experience with piezos is resumed to guitars and I can say that those I've tried do have way more bass and treble frequences present than magnetics, hence their rawer tone to them, almost hi-fi... magnetic pickups filter the captured tone, hence the huge variety one can find everywhere, piezos also do filter the tone but to a way less extent.

Piezos are way more demanding when playing, since they capture vibrations, a scratch in the guitar's body is then translated into audio signal, hence the (in my opinion) importance of using an onboard preamp (so it always travels with the instrument and is not forgotten somewhere). The preamp will filter out a huge amount of unwanted noise as well as level the frequencies (it kind of compresses them a bit, which is part of the preamp's job), bringing up the softer and down the harsher ones. In all of my piezo loaded electric guitars (5 in total), none has lack of bass frequencies when using piezo only tones, either with or without a trem bridge, either LR Baggs or Graphtech's.

I have an 8 stringer with Graphtech's and seldom down tune it to E1 on the 8th string. Never ever felt lack of bass frequencies, but, it's a guitar nevertheless. I also have a fretless 7 stringer with piezos from Graphtech and it sounds awesome, but the piezos alone on the high strings sounds dull and thin... it's a fretless guitar, sustain and tone are felt differently. However, the low end strings do have a nice tone to them, more so when combined with the neck magnetic pickup... yeah, I know, not an option for you, at the moment, that is...

@bostjan spoke about his experience with piezos from Amazon, not sure if it included a preamp. My experience is with both LR Baggs and Graphtech's Ghost system and both with their own preamps. I find Graphtech's to sound a little darker, but I think it is due to the teflon cover of the piezo-elements.

So, @cgmorrison, a question arises, what piezos are you looking at? DIY kind of thing or branded ones like those I've mentioned?


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## cgmorrison (Jul 28, 2021)

I'll be going for one of the branded setups. I'm not sure which yet. I've reached out to ETS because I like their designs and I've heard that they will add piezos. I don't know what their prices are like, though. If not them, then maybe ABM.


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## cgmorrison (Jul 28, 2021)

It would be nice to be able to try some out, but I'm currently living in the middle of the desert with no decent music shop locally.


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## CanserDYI (Jul 28, 2021)

I'm in the camp that believes the piezo and lack of frets will be difficult to get the clang you need.


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## odibrom (Jul 29, 2021)

CanserDYI said:


> I'm in the camp that believes the piezo and lack of frets will be difficult to get the clang you need.



He NEEDS a clang?


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## CanserDYI (Jul 29, 2021)

odibrom said:


> He NEEDS a clang?


Point taken!


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## cgmorrison (Jul 29, 2021)

After all of your very helpful input this guy answered all my questions when I stumbled across his video. This also happens to be the first song I was planning on learning. Oddly specific. Not the most amazing bass tone I've ever heard, but, to me, this shows me that I could at least get in the ballpark with some tweaking. Now I just need ETS to respond to emails.


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## Hexer (Jul 29, 2021)

I can try to record a short clip with only the piezos on my bass active if you tell me what kind of sound you're after. It's not fretless but maybe it helps...


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## cgmorrison (Jul 29, 2021)

That would be great. Archspire's Jared Smith's tone in Relentless Mutation would be my ideal tone. I understand that I won't be able to get the "clank" on a fretless, but it would be cool to see how close the piezos could get to that gritty sound.


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## Hexer (Jul 29, 2021)

cgmorrison said:


> That would be great. Archspire's Jared Smith's tone in Relentless Mutation would be my ideal tone. I understand that I won't be able to get the "clank" on a fretless, but it would be cool to see how close the piezos could get to that gritty sound.


Archspire, huh? Well, as long as you don't expect me to copy the playing.... 
I will try, it just might take a bit of time.

Also: it's not impossible to get somewhat clanky on a fretless:


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## CanserDYI (Jul 29, 2021)

cgmorrison said:


> After all of your very helpful input this guy answered all my questions when I stumbled across his video. This also happens to be the first song I was planning on learning. Oddly specific. Not the most amazing bass tone I've ever heard, but, to me, this shows me that I could at least get in the ballpark with some tweaking. Now I just need ETS to respond to emails.



That was cool, and dude was very very talented. I was just on the fence to me if that was a "usable" metal tone. Different strokes for different folks, but that sounded too woody for me to blend well with the cold compressed guitar parts. He might have had it sitting a bit forward in the mix to really hear what he was doing, maybe that's what didn't sit right with me.


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## CanserDYI (Jul 29, 2021)

Hexer said:


> Archspire, huh? Well, as long as you don't expect me to copy the playing....
> I will try, it just might take a bit of time.
> 
> Also: it's not impossible to get somewhat clanky on a fretless:



NOW THAT is how a fretless bass should sound in metal, man that was good.


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## bostjan (Jul 29, 2021)

Hexer said:


> Archspire, huh? Well, as long as you don't expect me to copy the playing....
> I will try, it just might take a bit of time.
> 
> Also: it's not impossible to get somewhat clanky on a fretless:



To my ears, that tone sounds perfectly useable for metal. The guy with the piezo only bass- the playing sounds amazing, but the tone is pretty far from what I would feel is acceptable to the style of music. YMMV.


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## CanserDYI (Jul 29, 2021)

bostjan said:


> To my ears, that tone sounds perfectly useable for metal. The guy with the piezo only bass- the playing sounds amazing, but the tone is pretty far from what I would feel is acceptable to the style of music. YMMV.


My thoughts exactly.


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## odibrom (Jul 29, 2021)

Although in fretted instruments, fingerboard material is a matter of aesthetics more than actual influence on tone, on fretless instruments it can, in fact interfere a lot. A wood fingerboard will sound drastically different to a metal one for example. ... and different woods will probably deliver different variations on the basic tone as well... food for thought.

... as far as taste goes, I also preferred the second video tone as well...


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## cgmorrison (Jul 29, 2021)

I bought the tab book for Archspire's Relentless Mutation album a while back. Some of the songs I'm just not there yet. I've got Human Murmuration and Involuntary Doppleganger down about 80%.

Watching the guys videos I think maybe his strong point is building guitars and not shaping tones. I liked his playing, but not his sound. 

I watched some Steve DiGorgio videos as recommended. I'm not sure if it's just his playing style, but I really wasn't digging it. I'll have to wait til I get home and listen to the last video posted.


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## Hexer (Jul 29, 2021)

Ok, here is some random noddling with just piezo pickups engaged:
https://soundcloud.com/user-917741605/piezo-noodling/s-lSuNWwnGrVb

Excuse the sloppyness and how simple it is, I use a pretty low action so it was difficult to keep fret-clank out of it as much as possible. This also means I had to play pretty softly which I am not used to. There is also one part where I just played like I normally do with fretclank and all. the overdrive towards the end is a Darkglass B3K.... Well not really, but a clone of that 

Setup was as follows: 
Esh Stinger I 5-string bass, only piezos engaged, wenge fretboard, maple bolt-on neck, ash body
EBS Multicomp
(Schalltechnik_04 GUMA Drive (B3K clone))
POD X3 Live simulating something like a slightly brightened ampeg head through a 410 cab


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## wheresthefbomb (Jul 29, 2021)

You should just do it.

Generally speaking, when posers/purists/gatekeepers tell you that something you're doing isn't "metal" or whatever their arbitrary metric is, that's a really good indicator that you're on the right path.


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## cgmorrison (Jul 29, 2021)

This might be a question better suited for the luthier section, but does anyone know where one could source a fretboard blank long enough to span the entire length of the bass? I found ones for upright basses, but they are way thicker and not quite shaped right. The local supplier (3 hours away) generally only has small turning stock of the nicer exotic woods.


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## cgmorrison (Jul 29, 2021)

I'm definitely going to do it. If I get tired of the sounds or can't achieve what I'm looking for I can always add holes for magnetic pickups.


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## bostjan (Jul 29, 2021)

I used to get my wood from a local exotic woods supplier, but they went out of business. There is also the tropical exotic hardwoods site that lists some very large pieces, but they seem to be out of stock with just about everything. With the lumber shortage, I'm not actually sure where you can get any material. If you are in a more populated area, there might be a lumber yard nearby that specializes in exotic woods and caters more to furniture makers than luthiers.

You might be able to find walnut if you can't get anything else, and the chain stores all sell maple boards online, but, again, there is a shortage of this stuff right now, so it'll take a little bit of luck.


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## cgmorrison (Jul 29, 2021)

I've got about 100 board feet of walnut lumber in my garage right now. It is my absolute favorite for furniture , but I'm not a fan of it for instruments. I'll just have to keep searching.


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## cgmorrison (Jul 30, 2021)

Just got the chance to listen to the DiGorgio video and the soundclip you posted through good speakers, Hexer. I liked his sound in that video much better than what I had watched before. Thanks for your sound file. With your playing and with the video I posted the piezos sound pretty hollow compared to how full it sounds with magnetic pickups. I think I might be starting to lean towards magnetic pickups. I just need to find the most discreet way to mount them to achieve the look I want.


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## Hexer (Jul 30, 2021)

Personally, I like having the piezos on this bass and I think I'll use them for recording some more "acoustic" sounding stuff but overall, for metal, I'll just use them combined with the magnetics.

Also aiming to get a 4-string version of this bass but probably without the piezo bridge to save some money. The dual singlecoils are more important to my sound than the piezos are.

I can absolutely see someone using piezos for this kinda sound though.


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## CanserDYI (Jul 30, 2021)

cgmorrison said:


> I've got about 100 board feet of walnut lumber in my garage right now. It is my absolute favorite for furniture , but I'm not a fan of it for instruments. I'll just have to keep searching.


What don't you like about using it for instruments? I have a walnut necked guitar coming my way and I'm stoked about it personally lol is it working with walnut? Or the end result you don't like


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## cgmorrison (Jul 30, 2021)

I love working with walnut. It has a nice smell. Pretty easy to work. I think it's fine as accent laminates in the neck. However, I made a walnut topped body for an RG8 neck and wasn't super pleased with how it looked. Remain stoked about your incoming guitar! It's just my personal visual preference.


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## cgmorrison (Jul 30, 2021)

Actually, there was a flying V I made a few years back. The body wings were walnut with a 1/4" flamed maple top and I think that was pretty sick. Maybe I just don't like it as a top. Searching through Google images for walnut guitar there are only a few options that were appealing to me.


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## LordCashew (Jul 30, 2021)

Here’s a thought I don’t think anyone’s mentioned:

What about creating an impulse response of a magnetic pickup you like and loading it near the beginning of your signal chain?

It’s getting pretty common for acoustic guitarists to make or use IRs to get their piezo pickups to sound more like a microphone signal. It should be just as doable to make an IR of a magnetic pickup, right? You’d just need DIs of your piezo bass and a magnetic pickup you want to emulate. You could even try to make an IR using a fretted bass if you want more treble, although you’d still have the attack and sustain characteristics of a fretless.


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## cgmorrison (Jul 31, 2021)

That's a pretty cool idea. I imagine I should be able to do this with an EQ matching plugin then create an IR out of it. Is that correct? Unless there is a way to make an IR of a pickup that I am unaware of.


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## ixlramp (Jul 31, 2021)

Wow, that piezo fretless video sounds amazing, complements distorted guitar so well. Nevermind what anyone considers an 'acceptable metal bass guitar tone', it is subjective anyway


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## LordCashew (Aug 1, 2021)

cgmorrison said:


> That's a pretty cool idea. I imagine I should be able to do this with an EQ matching plugin then create an IR out of it. Is that correct? Unless there is a way to make an IR of a pickup that I am unaware of.


That’s the gist of it. I haven’t done one yet myself but there’s plenty of info about it out there.


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## jack_cat (Aug 3, 2021)

Gentlemen: I am anything but a metal player but I have some experience with piezos.
I haven't seen that anybody has addressed the two interesting ways of shaping
piezo tone: adding capacitors and choosing a pre-amp - VERY IMPORTANT.
Because I play as weird a guitar as the rest of yous, I have gotten into do-it-yourself piezo tech
because I was forced into it in order to get down the road I wanted to go.

Since 2013 I have played a multi-scale nylon 9-string tuned F#1 - A4. I use home-assembled
piezo combinations. I bought a set of four piezo buttons prewired to a harness and had it
installed in my 2016 build, but I yanked it all out but the buttons, long story omitted, and...

Since then I use cheap $5 chinese piezos available online, with the red and black plastic housing.
I wire them in parallel to a single jack with a capacitor.
My latest and greatest rig is as follows:

(3) 3/4" piezo buttons wired in parallel with a .10 uf capacitor
across the jack poles; the jack is velcro'd to the butt end of the guitar. The signal goes to a BBE Acoustimax
"pre-amp" -- VERY IMPORTANT - and through its effects loop to a cheap chinese Ocean-Verb, thence to a
Yamaha mini-mixer which lets me plug a mic into my pedal board (also home-made: a wooden box w/ sliding top)
and run just one line out to my powered speaker or to anybody else's system.

The raw piezo is a doorbell in reverse. When it vibrates, it sends a signal at 20 million ohms. That's a lot of
signal repetition: and these cheap piezos fail inside of two years, which is why I have assembled several!
Either the ceramic disc shatters, or the solder joint fails because the wires fray at the point where they enter the solder blob. So be warned, if you are using these, to have the next one ready before the first one fails.

For this reason, I stick them on the exterior of my guitar, and there, they become tone controls. I can move them around and adjust the relative strength of the different strings.

The 20-zillion ohm signal has to be stepped down to a line level of 600 ohms, or to whatever the input impedance on your amp is. This is the job of the "pre-amp" - it doesn't have to "amp" hardly at all, because you can get gain from the piezo button, no problem. What is absolutely required is to step down the impedance, and if you don't do this, or do it poorly, then the pickup sounds like crap, tinny with too much high frequency. Inside the preamp is a component called a FET, which you can treat as a black box, but you need it. All the rest of the stuff in the preamp is bells and whistles, while the FET is the principal engine.

There is a bass player up in the northwest USA, maybe you can find him online, who makes a FET jobby that runs on a flat wafer battery and fits in a matchbox-sized cavity in the bass body. The closer the FET is to the piezo, the better it works. Mine is a full 10-foot cable away, but it still works OK. I had that guy make me a custom rig, and it sounded awesome, but because I did not install it close to the piezo enough, it picked up radio frequencies, awwww shooot!

The BBE Acoustimax works well: even if you are among those who hate the proprietary Sonic Maximizer, it has a good sweepable mid, a notch filter adjustable for freq and depth, and enough in/out options. I like it very much. A big plus for me is there is no LED screen - yay! - and the buttons are big and knurled, and each button has just one function. Easy in the dark. (I once lost a whole recording session trying to use the miniature buttons on a Sony mini-disc recorder, and my Zoom H2 isn't that much better. For this reason the Zoom A-2 preamp also rates last among the ones that I have used. I like big fat knobs that do one thing.)

The first preamp I got that worked was a Boss AD-2, which is a FET with 3 knobs, a tone, a reverb, and a notch: the notch works, the others are completely inadequate for tone shaping, and must have another EQ downline. But for a Boss pedal chain this would be the go-to tool for first in line pedal after the piezo.

I can also freely recommend the Zoom A-2, which my duet partner used for many years. It has a user interface like a two-button watch on steroids, and I hate it, but it does the job. I know there are similar boxes for bass, but I haven't tried them.

The first capacitor that I used was a .022 uf, which was recommended on the Cigar-box Guitar site. The next stronger capacitor is .049 uf, and the next one is .1 uf, which is what I am using now. I have no freaking idea what these specs mean. What they do is bleed off the high frequencies from the signal, soldered across both poles of the jack. I have no idea why this works. The .022 did not do this well enough, and I had to turn the treble controls all the way to zero on both the BBE and the mixer. With the current rig, I still turn the treble way down, but I have a little bit more room.

Capacitors are really cheap. Radio shack doesn't have them. I got them from Steren, a Mexican electronics supplier, for a few pennies each. I bought an assorted bag online from China, but they never arrived.

Capiche? Bottom line: tone shaping is done in four ways:
(1) Piezo placement on or in the instrument, look for sweet spot.
(2) Capacitor at jack to cut highs. Different size capacitors give different tones.
(3) FET to step down impedance - ESSENTIAL
(4) Signal processing up the wazoo, because you have to.

Some guy set up a piezo rig with a multi-poled switch to test different capacitors live.
I haven't done this.

- jack


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## GenghisCoyne (Aug 5, 2021)

would sending it through modeling software set up for a "good" metal bass tone be unrealistic?


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## jack_cat (Aug 10, 2021)

GenghisCoyne said:


> would sending it through modeling software set up for a "good" metal bass tone be unrealistic?


I don't have any experience with modeling software except inside the Zoom A2 preamp, which includes picking a guitar-model-sound as the mandatory first of the ahem "three wishes" that that box gives you. The choice of a model in that box does have a significant effect on the tone. However, it is applied after the FET and I am in some doubt that you could effectively process the piezo signal without the FET. I have tried to run the raw piezo signal through a 31-band EQ without the FET in front, and I couldn't get a sound I liked. But because i don't know any other modeling software, I don't rule it out, and the experiment is just sitting there waiting for you to do it and report back to us who are eager to know.

As an experiment, it makes perfect sense: feed the raw piezo signal through the modeling software and see what happens. It doesn't cost anything to try, I presume.

The 2nd experiment would be to apply the standard hardware signal processing before the modeling. This would start with the FET and then as a 3rd stage experiment include EQ before modeling. I presume that the reverb should come after the modeling. Anyway, please do it and let us know. Thanks.


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