Experiments with the 104-Z Analogue Delay

The Moog Forum Moogerfooger Forum
1

I have been thinking about the MF-104Z Analogue Delay. What seems rather unique about this delay is the use of an effects send and return.

So I started thinking about this composition:

http://www.youtube.com/watch?v=Jfssj80oNuM

Alvin Luciern was brilliant in his out of the box thinking about experimental music at a time there was not a lot of equipment around. Lucier’s works span the time from 1952 with his “Kyrie” for young woman’s voices organ accompaniment 2000 with “Piper” for solo bagpipes.

http://alucier.web.wesleyan.edu/index.html


The work I posted is one of him most famous by the title “I am sitting in a room” written in 1970, a work written for voice and electromagnetic tape. This same year the minimoog came out. At this time, digital electronics were not around so either bucket brigade or tape delays were used.

“I am sitting in a room” is a rather simple but powerful idea. Think of yourself, simply, sitting in a room and talking into a tape recorder. Then, you play that back in the same room using another recorder and repeat the process several times. What happens is that the recording begins to take on the characterisitics both of the tape and the room.

So what does that have to do with the fooger delay?

Well, here is my idea. I have discussed it here before but I started to do some experiments and just ordered a few DIY instrument electronics to complete it (or at least the first phase). I was walking in a Home Depot of all places (no musical instruments there right?) and I saw it. PVC pipe. Simple pipes which make for great resonators.

So I go a mic and hooked up some of my foogers to it and right away the resonanator (as I call it - you might call it PVC pipe) changed the character of the freqbox which became a strong stable waveform expecially at the resonance frequencies of the resonator.

So then I go this idea. I just ordered a cheap midrange speaker. I am going to glue it to the PVC. One end goes to the effects send. On the other end is a mic or contact mic (I ordered a piezzo because it can be shaped to the inside of the pipe) and this is connected to the return. The idea here now is that at short delay time and relatively high feeback, the fooger is going to start picking up the natural resonance of the PVC pipe much the way Lucier picked up the charactersitics of the room he spoke into.

I am not sure what I will get but there are some variations on this I want to try and I will post what I find. I guess this is a long way from the typical fooger stuff but thought I would give it a try being an experimental composer.[/url]

2

Be sure to make a video, as this sounds like an amazing idea! :mrgreen:

3

It sounds like an interesting experiment. I tried a digital reverb in the loop of my 104Z, but found that the effect wasn’t particularly interesting. Once the sound dispersed it stayed dispersed, you know?

I think your pipe is going to act more like a bandpass filter, which will make for some particularly interesting effects (and runaway oscillations) when you find the resonant peak. You can get a similar effect with a low pass filter with the resonance turned up fairly high (but not self-oscillating).

Bryan

4

Hello,

I’m not sure about the delay aspect, but something close to this was done with a rather popular 80’s recording.
Quincy Jones, in his autobiography stated, “We put the final touches on Michael’s vocals on “Billie Jean”, which he sang through six-foot cardboard tubes”. The context of the quote was the chapter titled,“Thriller”.
The delay, as a variation on this will no doubt do some interesting things.


Regards,


Lawrence

5

What I am trying to produce is something similar to Lucier’s “I am sitting in a room”. Now clearly the tools being used to do it are different. In Luicier’s work, the effects is produced by painstakingly recording an iniitial recording over and over again. If you listen to the link you will hear something very different than a low pass filter. In this case, the coloration is a product both of the room and the tape.

Before the age of digital reverb, reverb effects where produced primarily in three ways:

  1. Spring reverb (found in many older guitar amps - and probably some new ones as well)
  2. Plate reverb (much more difficult to implment)
  3. Echo Chamber

What I want to build is a variation on that.

I don’t expect the frequency response however to be the same as a low pass filter found in this study:

http://www.ndt.net/article/v10n11/volkovas/volkovas.htm

This particular study was in regard to sediment in pipes but the frequency response curve gives you the idea of what I am talking about. You can see several resonance peeks.

This is a pretty intersting discussion of filters I found on this forum:

http://www.moogmusic.com/forum/viewtopic.php?p=12321&sid=0b89e977c048726eb85ef32721dd8312

You can find frequency responses for low pass fitlers here:

http://images.google.com/imgres?imgurl=http://www.timstinchcombe.co.uk/synth/poles/4p_tf_static.gif&imgrefurl=http://www.timstinchcombe.co.uk/synth/poles/poles.html&usg=__1PGeUQMnypc7UAIyWXcxlhRJoaI=&h=448&w=448&sz=16&hl=en&start=5&um=1&tbnid=eUlgYlZYsjL8QM:&tbnh=127&tbnw=127&prev=/images%3Fq%3Dmoog%2Bladder%2Blow%2Bpass%2Bfilter%2Bfrequency%2Bresponse%2Bcurve%26hl%3Den%26sa%3DN%26um%3D1

I am in no way and expert or even a neophite when it comes to electronics and filters but I do know there is a subtantial difference between the frequency response of a fooger LPF and a PVC pipe.

I also am planning on using a piezzo pickup for a few reasons. First, it can be molded to the inside of the pipe but also because it has a good frequency response. It will also react differently than a mic and if the I put it in front of an amp of the audio out of the delay it will also pick up and react to those vibrations.

All of this is going to creat a physical system with what I hope to be interesting audio properties that I hope to exploit.

I ordered most of the parts yesterday so in a few weeks I should have some resuts I can post her.

6

Been there, done that.
It was fun.

7

I understand that. My point was that the pipe isn’t going to act like a room, but rather more like a filter. Rooms have lots of resonant modes compared to pipes. As you mentioned, the tape also acts to distort, filter, and modulate the sound.

Before the age of digital reverb, reverb effects where produced primarily in three ways:

  1. Spring reverb (found in many older guitar amps - and probably some new ones as well)
  2. Plate reverb (much more difficult to implment)
  3. Echo Chamber

What I want to build is a variation on that.

I wonder if you could find an impulse response of a pipe for use in a convolution reverb.

I don’t expect the frequency response however to be the same as a low pass filter found in this study:

No, of course not. I suggested that the pipe was similar to a band pass filter. Then, I suggested you could get potentially similar results with the low pass filter, at least to my conception of what sound you are going to get with the pipe in the loop of the delay. You set up a resonance (but not self-oscillation) with the filter and the repeats of the delay get increasingly focused around that resonance. I suspect that is what will happen with your pipe.

Like I said, I’ve used reverbs in the loop of the delay and didn’t find the effect particularly useful or interesting. Your mileage may very.

I am in no way and expert or even a neophite when it comes to electronics and filters but I do know there is a subtantial difference between the frequency response of a fooger LPF and a PVC pipe.

Of course. I wasn’t suggesting otherwise. More that you can get a first order approximation of what you’ll hear using the gear that you already have.

I also am planning on using a piezzo pickup for a few reasons. First, it can be molded to the inside of the pipe but also because it has a good frequency response. It will also react differently than a mic and if the I put it in front of an amp of the audio out of the delay it will also pick up and react to those vibrations.

I would probably use a transducer from K&K. They’ll have pretty good output and are (potentially) more ‘musical.’

I wonder if you’ll be frustrated by the initial repeat of the delay not passing through the loop on the delay pedal.

Also, the speaker that you use is going to drive (no pun intended) the frequency response of your system quite a bit.

8

I just posted a long response to this and it never took for some reason. I will shorten it for time sake.

I understand everthing you are saying. It’s true that a pipe, being short, does not have long tailed reverbs. If you think about this in terms of impulse response then yes, most of the effect of the filter is going to be filtering. Sure, the speaker (midrange) will act somewhat like a band pass, but the interaction of all the elements I mentioned I am hoping is going to be more complex. Complex physical systems can yeild some fascinating results. Karlheintz Stockhausen did many many experiments with all sorts of electronic and acoustic equipment. I am becoming a bigger and bigger fan of his but unfortuntely like Robert Moog he is dead.

I know that you can get impulse responses of pipes and all sort of things. I have the 2nd to latest version of Altiverb which I very much like and also use the another one that used to be freeware that I run some Spirt Canyon impulse responses through. I tend to twist things and abuse them so that they are not used for their original purpose. You could also call it bending in a sense. Spirit Canyon’s IRs are far from standard. But Audio Ease Altiverb had some nice experimental stuff including echo chambers and pipes (big ones) and even toys like the Zube Tube:

http://www.zubetube.com/ which of course on hearing you would have to admit is the “ultimate cosmic sound machine”. Well, mabye not but altiverb liked it enough to get it’s impulse response and it resembles this:

http://www.youtube.com/watch?v=DC9w4KWEgJE

Of course I dont’ think the boy in the Zube Tube commerical has mastered circular breathing or the fine points of dreamtime but you can’t have everthing when making cosmic sound machines. :slight_smile:

There is also an interesting article in Electronic Musican but on intersting recording techniques using old equipment like dictaphones and even childrens toys.

Here is the Hanna Montana one for those who like kiddy pop, not a fan myself but I don’t think Miley can play as mean a trumpet as Miles Davis so…

http://www4.shopping.com/xPO-Birthday-Express-Hannah-Montana-FM-Wireless-Microphone

OK, a little diatribe of humur there but my point is that if you are dealing with what is “musical” when you enter into experimetnal music, what is clear and precise is not always the way to go.

Consider this from John Cage:

http://www.youtube.com/watch?v=Ep5fNEeoh74

Wonder what would happen if you ran that though an LPF fooger :bulb: :stuck_out_tongue:

Perhaps, something like this:

http://www.youtube.com/watch?v=D89ACmoDmVQ :open_mouth:

Bottom line, I am looking for color not somethng precise. I want to blend and abuse foogers (not the circuts just the sounds) with other unusual sounds and come up with somethng new and I hope musical.

Hope that makes some sense. Otherwise, I guess I will have to go back to the experimental drawing board. Of course, I coudl get a teen with a lousy voice and a bad attitute and turn her into a lip sinking adult who can handle her own life let alone her kids and makes lots of money, or no, wait, that is pop music isn’t it. I think I will stick with my PVC tubes and foogers and who know what might happen.

9

I like your pvc idea, but I just has one sugguestion. Get either a larger pipe to go over the pipe you already have, or a smaller one to go inside. This way you can create more variation in the sound. Kinda like turning room reverb into hall.

On second thought get both, a larger and a smaller pipe. Using them all at once could be fun.

10

I actually did think of a few variations on this. One would be to have multiple pipes at tuned lengths much like a pipe organ. Each would have its own speaker although that could vary (for example using midrange, tweeter and woofer perhaps) and then mix them together.

My other idea would be to basically do what you are talking about and create a slide much like a trombone so I would vary where the resonance peaks are.

11

Years ago when I was working in a music store we had what we liked to call “The sewer pipe reverb”. It was an amp and speaker into a section of corrugated pipe with a mic at the other end. Very different sound. Lot’s of resonance and many short tails each affecting the others. I don’t remember if it was a homebrew or from a company. I’ve never seen one before or since. (We had a lot of strange things then. Chapman sticks, sitars, hurdy-gurdys, synths, Heil talk boxes, tape echos and unfathomable studio gear.) The thing was large, but not as large as a plate reverb and a ton lighter. I don’t remember kow if it was one pipe or multiples. It was 30 years ago.

12

You hit the nail on the head when you said:

each affecting the others

Electronic circuts like foogers are great and even digital eletronics are great but they don’t often create the kind of feeback situations that you can get with physical objects. Impulse response is also a great way to sample reverbs but there are certain interactions in physical systems that I don’t believe can be duplicated by impulse response.

The object you describe is very much like the one I am trying to make with the addition that I add of a piezzo pickup which I am not adding for sake of utility but to intentionally create more interaction. The pipe vibrates, which effects the speaker. The contact mic is pickuping up all these vibrations and feeding them back. I don’t think this is going to respond like impulse response. The idea with impulse response is that by sending a very short term burst of theoretically a zero duration time and all frequencies event, or what is called a Kronicker Delta, you can convolve (sort of like a big sonic adding machine) a sound so reproduce the reflection and filtering of sound in an acoustic environment. The problem is that physical systems this complex are going to react at different volume levels and frequecy distributions in ways that are not going to match the limited physical model of impulse response.

I ran into this with additive synthesis. I spend a few years fooling around with this to realize that it has limited usefulness. It’s based on a mathetmatical theorem of Fourier that is based on static waveforms. The problem is, and anyone who looks at a sonogram of an instrument, is going to realize that waveforms of instruments are anything but static especially in their transient phase. When an oscillatiing system is first exitied it is going to take a while for it to settle into periodic vibrations. Books like Roads “Microsound” are great books to explain granular theories which often come closer to the truth.


http://mitpress.mit.edu/catalog/item/default.asp?tid=8587&ttype=2

In fact, for those who have some level of scientific/engineering or mathematical background I would reccomend anything from MIT press.

Many want to gloss over this stuff as to hard so we tend to go with our standards. It’s like a man who buys a hammer which the manufacter claims can do anything and then use it to bang a screw in. Foogers, digital effects and synthesizer, modular synthesizers and physical instruments and effects can all be tools musically. Mics and loudspeakers can to and their placement (which you can see in the work of those like Stockhausen and Lucier).

Moog stood in a rather unusualy position of appreciating that which is “musical” and that which is technical. If you have ever opened up a Fooger to mount them, you probably took a peak. Not exactly the average effect box is it? Not just a few op amps or oscillators or timing ICs? Blending knowing of the physical world and the musical can yield great results.

You also mentioned those instruments with sympathetic and complex vibrations. Here are a few:

http://www.shrutibox.com/

http://www.youtube.com/watch?v=xLlIbMA6VFA

There are lots of examples and the idea of sympathetic vibrations has been used in instrument making for a long time.

Or then again, perhaps we can just pull out the latest program to make digital sound and trust that that hammer can screw in nails. I guess its a question of how far out of the box you are willing to go.

13

You seem to be taking my comments in the wrong light. I realize you aren’t familiar with the music that I’ve made, which has often involved physical systems in different ways (mainly prepared microphones, prepared instruments, and prepared spaces). My comments about things to try (filters in the loop, impulse responses for convolution reverbs) are just that - things to try. They aren’t intended as replacements for the mechanical system, but instead, things that might give you a hint what effects you’ll get or inspire new experiments. I’m trying to be helpful, not discouraging. Your comment about treating a digital box as a do-it-all hammer is insulting.

14

Sorry if you took offense, I did not intend it. I was not really responding to you but a general impression that is out their (i.e. my hammer comment). Please continue to respond. Your responses have been the most enlightening one’s here so please don’t take any offense and I will try to clarify my position more in the future.

15

One of the recomendations made here was to use the MP-101 for the effects loops for the MP-104Z. I tried that today and was rather impressed. While not creating the slow coloring effects I intended, it did create some incredible drones. In fact, all I need to do was turn up the resonance on the 101 to create great drones that seem to create there own dynamic effects. I also attached the LFO out of the CP-251 into the delay time and the combination of the two was fairly dramtic. The mixing the LFO and the envelope out of the MP-101 on the mixer and into the delay time create even more dramatic effects. I have never heard anything digital come even close to what I heard.

Granted, this is a bit difficult to control but worthy of some experimentation.

I am still working on the original part of my plan. My speakers came in for the PVC pipe I need to get some expoxy but the speakers works worked well and simply putting my ear up against the other end of the pipe produced a substantial coloration and short tailed reverb.. Using the MP-101 in the effects chain produces to strong a coloration and no smearing of the filter over time (short tailed reverb) so I am confident that this plus using a piezo pickup, which I also have and have tested, is going to produce an interesting effect. One other element I am hoping to get is a longer and smaller diameter pipe that I can slide back and forth and change the resonance frequencies of the pipe.

I should have time to work on the project more this week and perhaps have a finished product for testing soon.

16

I wanted to update people on this project I have been working on. I got all my parts and with a bit of carpentry and gorilla glue I was able to screw a speaker on to a board which I mounted on the PVC pipe I am using as a resonator and it fact, extended it with a narrower pipe so now its about 4 feet long.

I did run into a bit of a problem although not insurmountable. I never really thought about it before but its not clear to me what electronics I can used to amplify line level signals to drive a speaker. Clearly stereo amps do this as well as instrument pre-amps but also guitar amps. I am not sure which is the best or if there is another alternative.

Sending the effects send of the MF-107 directly into the speaker produced only a weak signal. I am using an 8" midrange speaker. An accidental but interesting result is when when I pluged it into the mic rather than the headphone jack of a boom box. Very colored and at close range very bad feedback but the darn thing started working like a mic. It could be very effective as an effect or even placed at the other end of the resonator.

Anyway, at the moment I am getting enough srength in the signal so that the speaker really starts to vibrate the tube enough to get a strong response from the piezo pickup that I want to use.

If anyone has any ideas on how to effectively, and with minimal distortion, pre-amp a line level signal into a speaker please let me know.

17

I had wondered what sort of amplifier you planned to use. You could do all sorts of things on the cheap. An old hi-fi amp is my first thought. A used Crate PowerBlock amp might make sense, too.

18

You can get single chip amps from mouser and take a line level to a half to two watts cheaply. The cheapest I can think of would be to take an amp out of a PC speaker housing.

19

Paia has a few amp kits, ranging from 1W to 8W…they are small, and could be housed in a simple project box. :wink:

20

Thanks for the suggestions. I will look into all of these.