Members pepsi_max2k Posted July 22, 2015 Members Share Posted July 22, 2015 Hey guys, not sure if this is the right place to put this, but you seem knowledgeable enough I'm experimenting a bit with some piezo pickups, and trying to figure out the best way to make and use them. I have a few specific questions right now I'll put below, and then just random stuff after that that you may or may not be able to point me in the right direction with. What I'm using so far: Preamp: http://www.cherubtechnology.com/eq_d...&id1=43&id2=48 Discs: http://www.maplin.co.uk/p/3v-ceramic...cer-2718-yu87u Amp: http://www.tdpri.com/forum/modeling-...tang-i-v2.html 1. I cut a cheap mono audio cable (basically like this but without the conductive pvc: http://www.heritage-music.co.uk/shop...aight-mono.jpg ) in half and soldered it to the discs. Now the whole cable is basically a pickup (and the first part of the preamp, but nothing after that). I don't know if this is because any knock/vibrations on the cable travels up to the piezo and back down, or if the cable is effectively now a piezo too, but I don't like it. Is it fixable? Better cable? Better connections? Better anything? 2. I have to boost the gain quite a bit, which then picks up footsteps, or the tv (very quietly), and can cause feedback with the amp. Any obvious way around this (shielding the whole piezo + cable somehow) or just put up with it? So anyway that's the basic stuff for now. In general though, any tips? Have any of you guys made some and know some stuff to avoid? What's so special about http://kksound.com/products/twinspot.php to make it $80 and not $2 (basically what mine cost)? Does my 2-into-1 count as wiring in parallel (see pic)? Currently sounds a bit like this after random fx (ignore the clipping, and I only have half the instrument miced up): Thanks for any advice. Link to comment Share on other sites More sharing options...
Members WRGKMC Posted July 22, 2015 Members Share Posted July 22, 2015 If you used television, cable TV stuff with the solid core its the wrong cable. Its 300 ohms, designed for high frequency applications, not audio. I can see where the sound may travel through it because of its solid core. Next, those disks suck. They have crappy tone, low output and don't come nearly close enough to sounding acoustic like. In my trials the best you get is muted low quality tone which sounds awful. The disks get all wood vibration and practically no metal tone from the strings. What you need is a bridge piezo sensor. You can buy them as low as $2, but you have to know the size. These fit under your bridge saddle and then you drill a small hole at the end under the bridge to feed the wire inside. Most come with a 1/8" jack you just plug into the preamp. You then run a normal Hig Z audio wire to your end pin jack so you can plug it into your guitar amp. The preamp should have enough gain to amplify the sensor for a decent quality sounding output. The only thing you may have to so is sand down the bottom of the bridge saddle to lower the strings. The piezo saddle pickup is thin but it does raise the saddle up about a millimeter so you want to compensate by lowering the height a little. Draw a line on the bottom of the saddle so you know how much it needs to be lowered. Then tape sandpaper to a wood block and rub the saddle on the flat block and check and make sure the saddle bottom remains flat so it contacts the element evenly. This job isn't that hard to do and the sound quality will be much better then those low fidelity disks because the strings will inject sound nearly directly into the sensor. Link to comment Share on other sites More sharing options...
Members DeepEnd Posted July 22, 2015 Members Share Posted July 22, 2015 An undersaddle transducer will also give you what's known as "piezo quack" because of the way the piezoelectric element reproduces sound. I tried piezo disks similar to yours a while back when I made a DIY stompbox that was supposed to produce a percussion sound. There wasn't enough signal and, as a result, there was a lot of hiss and noise. What you've done in your case is to turn the entire top of the guitar into a microphone. A feedback buster will help but only up to a point.The cable you linked doesn't look like TV cable to me, and you did say it was "audio cable," but since it's a drawing instead of a photo I'll withhold judgment for now. Anyway, a properly executed "soundboard transducer," like the K&K or the much cheaper JJB Prestige 330 (http://jjb-electronics.com/prestige-330.html) is well liked by the folks over in Acoustic Guitars. Frankly, I have no idea why they cost so much but since the cheap ones you and I made pretty much sucked and the K&K and JJB don't, I'm guessing there must be a reason. Link to comment Share on other sites More sharing options...
Members pepsi_max2k Posted July 23, 2015 Author Members Share Posted July 23, 2015 Hey guys, thanks for the replies. I should probably clear some stuff up: - This isn't for a guitar. It's for a Steelpan - an idophone similar to a handpan / hang. I have no saddle or wood to vibrate or sand . Maybe I should have put this thread in DIY... :\ - I'm experimenting, so spending money isn't the aim unless it's gonna improve things considerably. - See pic of cable below. It's a very thin and cheap mono audio cable (stranded copper core and ground, thin plastic covering both). Chosen because I didn't want an extra audio wire hanging around, didn't want something heavy hanging off the piezo, and it was all I had at the time - I tried a cheap undersaddle piezo (see pic) that came with the preamp. If you think the discs suck, oh boy.... this thing only ever picked up itself. I'm loathe to try a bar piezo at all due to the instrument's physical note arrangement (see pic again) - I'm guessing a bar would be more unfairly biased towards whatever notes it ran between If anyone has a link to a "very high quality" piezo disc (supposedly used in the JJB etc) then please let me know. The pan's root note frequencies range from 261.6 Hz to 1318.51 Hz, with overtones probably up to at least 2637.02 Hz. - Is there a way to limit the pickup's sensitivity so I don't "turn the entire top into a microphone", yet retain signal level? I'm trying multiple piezos, 2 so far, I think it needs 4 at most, but it does feel like I'm just creating a massive mic / feedback machine :\ Link to comment Share on other sites More sharing options...
Members WRGKMC Posted July 23, 2015 Members Share Posted July 23, 2015 You're talking about a calypso steel drum. My father lived in the Caribbean for awhile and brought one back to me as a kid so I'm familiar with the instrument. Its a unique from the point it was made from old oil drums that used to wash up on shore during the WWI or II. The islanders found they could bend the steel top of the drums into domes and get different pitches from the bends and they would tune them to pitch and play them like an Xylophone. Pretty cool actually and out of all the instruments out there its actually very new compared to others. The music these steel drums produces were actually unique too. Problem you have is amplifying it. You have three major problems. One its a single head that produces multiple chimes. Second physically attaching anything to the surface changes the pitch, The pitches produces are localized to the positions of the domes but the entire head resonates too. I understand now why you'd have issues using contact mics because a contact mic cannot be isolated. its like hearing sounds under water. If you're ears are under water in a pool and someone makes a noise on the other side of the pool you hear it clearly because solids and liquids conduct sound much better then the air does. What you're hearing with a contact mic is the resonance of the entire steel top, not the isolated domes producing tones in the air. There's only two options for amplifying this instrument. One is obviously a mic which is the preferred method used to record and amplify the instrument. The second may work in theory but you'd have to experiment and see what the results are. A pickup coil like the kind used on guitars will pick up metal vibrations in a localized manor. If the magnetic coil is placed close under the individual domes without touching, it should produce sound the same as a guitar string does. It would essentially be similar to tapping on a mic diaphragm. You can either make your own single pole pickups using a small relay and inserting a magnet from a single coil guitar pickup like this http://cdn.instructables.com/FHJ/JBXG/H2WEWRQ4/FHJJBXGH2WEWRQ4.LARGE.jpg Or you can look around and find someone who can make them for you. This company makes them for bass guitars. http://www.atlansia.jp/ You would need one for each dome of the drum and the suspension of the coils would be fairly difficult. Some of the domes close to the edges don't have allot of space to get a coil under them so you'll have to judge if its possible. The cheapest way is to use a mic. Of course you'd have issues with feedback and the best placement of a mic is above the head so you capture overtones properly. It would be interesting using the coil method because you could crank the amp up and not be worried about as much feedback like you would with a mic. Micing it would have better results through a PA for sure because a PA is Full Frequency and would produce natural tones. A guitar amp is limited to midrange frequencies so its going to have allot of ring frequencies in the midrange. These are essentially bell tones that are in the same range of many mic feedback frequencies so scooping the mids is what you'd want, not boosted mids that exacerbate the problem. Anyway, that's my opinion. I don't think your Piezo experiments will work as you've already found out. The cable isn't the problem. The entire head is being picked up instead of individual domes and having the sensor mounted to any of the domes will lower the pitch the same was as if the metal was thicker. Link to comment Share on other sites More sharing options...
Members pepsi_max2k Posted July 23, 2015 Author Members Share Posted July 23, 2015 Hey, thanks for the details. I'd love to try magnetic pickups, but just don't have the time or money to get 29 of the things As for it working or not, in theory it can, but these guys mostly used magnetic and strain gauge pickups (the piezo details are generally limited to saying they worked better). https://sta.uwi.edu/eng/wije/vol1802...icSteelpan.pdf Also hand-pan users (basically an inverted steelpan) tend to be using piezos too - http://www.handpan.org/forum/viewtopic.php?f=10&t=7522 . So I have confidence, just not enough experience yet You're right about putting anything on individual notes though - it kills them, so the space between notes and the skirt are all you can use with contacts. I don't quite fancy figuring out how to hang magnetic pickups under each note either. There's a decent article on regular mic useage and placement at https://sta.uwi.edu/eng/wije/vol3502...dRecording.pdf , but that's way too easy and uninspiring. And tons of details on production and tuning at http://stockholmsteelband.se/pan/tun.../pantuning.pdf . Anyway basically the advice so far is eq the midrange out at the preamp, move the amp as far away as possible, and get some better pickups? I can work with that Link to comment Share on other sites More sharing options...
Members WRGKMC Posted July 23, 2015 Members Share Posted July 23, 2015 These are different then the calypso drums. they look more like a Bar-B Cue pit. He says: I had been placing the pickups on the inside, experimenting with placement on the top and bottom half. When we moved them to the bottom half, on the outside, I was once again blown away and reminded why I wanted these pickups in the first place. Placement of a Piezo element is a key item. If there's an outer chamber that resonates like the drums in the video shows then I'd try different places and see if you can find a spot that picks up the resonation of all the notes. he also uses the K&K elements that are small and absorb less resonance and probably allot better then the Piezo buzzer type you're using. He did use a PA, not a guitar amp too so maybe that provides the extra fidelity a guitar amp lacks. Link to comment Share on other sites More sharing options...
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