Theo Verelst Local Diary Page 26

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Tue Aug 2 0:10     2005

That was the start data, now it's august 9, lot of stuff, most relevant to current life, but maybe not hip.

This picture is taken in scheveningen, the Hague:

Is Verelst in Surround 7.1 ?

Well, lets take it easy. First, when Theo is in such things, he really is in such things, of course...

When I was I guess 15 (I'm from '66)  I made my first real impressive big audio system with solid Phillips 10 inch woofers and high quality Phillips tweeters in heavily srewed together 18 mm "spaanderplaat" (sort of MBF but of woodchips) with airtight kit in the corners and ample glasswool for damping, which matched with a 2x75 Watt (measured power) self made amplifier and my self made 4 channel stereo mixer which all made for good shows at school. I was way to far out for just about anyone, also qualitywise. Great fun.

Anyway now I'm into further challenges, studio and PA equipment, with High End HiFi quality in mind, but then louder and preferably even better, less limited, suitable for life sound and not affraid of 'straight' loudness, without the speakers and amp starting to sound like they are 'working' for a party level sound (distorting, essentially).

So the big system has been used for queens day balkony sound reenforcement, audible through the whole street, stopped because a neighbour thought the bass pounding and raw power (about 500 watts I guess) was enough for the day .. And what a quality! I received thumbs up, some dancing people, request for more loudness (early in the day, from across the street) etc, and of course checked downstairs myself,  and what a quality!

My current project is a set of medium sized powered, bi-amplified 2 way speakers, with hard alluminium edges, plastic protected corners, and water resistant skay covering, with pioneer woofers and good dome tweeters, and absolute world top pre/filter amplifiers, and active, electronic filtering built in. Veeery high quality, so they are also made to look good, of course:

      Cutting the slay to fit before Bison kit is applied

      the sides in setup

      The result (except for the left side because I was out of glue)

      Rugged and well looking notice the double
      cables for this slave biamped speaker

Maybe not justified, all this attention for the exterior? Well, uhm, no, in fact quite appropriate, see these figures:

(woofer specs)

The frequency graph (assuming no messup through the enclosure) is pretty good, considering a double filtering pole at 5kHz, just before the peak. Within a few dBs until 50Hz, thats good.

Remember that the specs of the amps and the preamp (and filters) are very good, as in studio quality.

Directly comparable, maybe better than examples from the famous Quested studio monitors (check the non-bass reflex smallest offering they have and compare). Speakers of theirs of comparable power as these are about $2000. A piece.

Now for the 7.1, actually I've tried a 5.1 or I call it 5.0 (the mid is only a subwoofer) from a Sade music DVD a while ago, which was good, but I could only use a AC'97 DA converter set, which is NOT so good, not compared to my USB converter.

My setup is to create with my self made reverb (see below) 4 extra channels, intended for side (short reverb part) and rear (long delay times).

The main big speakers are probably the best by far compared with most other speakers, so they are still the main ones!

The view from the main listening chair.

To the left, the side speaker (perspective shows it larger than it is) and the rear speaker, all at ear hight.

Amplifiers / Speaker combinations:
Main speakers: big 4-way (12" woofers, low squaker, high squaker, high power dome tweeter), 2 x 100 Watts RMS continuous amp
Centre subwoofer 15 inch (only front plate, no enclosure) (under 50 Hz, 12 dB/oct analog) about 250Watts RMS or about 70Watts (depending on supply) amplification
Side speakers: 2-way (small 15cm pioneer woofer/mid, small dome tweeter) 2x50Watts amplifier (depending on supply)
Rear bi-amped powered portable speaker set: rugged medium size enclosures with 17.5cm pioneer woofers (high frequency cone removed) and heavy dome tweeter, one with builtin 4 channel amplifier of very high quality with 120 Watt toroid transformer supply and analog 12dB/Oct electronic seperation filters around 5 kHz.

In total that is
   2 (main)
+ 2 (bridged sub)
+ 2 (sides)
+ 4 (biamped rear, what a luxury!)
 10  amplifier channels
(or 5 stereo amps) with a total power of about 200+250+100+120= 670Watts ! For real, I mean more or less R(oot) M(ean) S(quare) continuous power, not pmpo music power on a good sunday with the mains running at 240V and a measurement error of 400 percent, but normal power, which could be fed into lightbulbs of the equivalent power. Some amps and one supply in the set might not be up to this power continuously, but still that is of course significant power.

Which now is never used because of the attenuating mixer I use, and in fact the the most power greedy part, the 15 inch sub, is now limited to about 50 watts (because I use a old computer supply instead of a good and charged car battery), so the total noise is very limited, but of course impulses and peaks are very transparent and effortless with so much power reserve. The total number of speaker units in action is 2x4+1+2x2+2x2= 17.

   On top the main 2x 100W amp, lower left, the 4x200W car amp, with computer supply

   the small (but good) portable amp with supply options: small wall
   wart (few wats, charging), 20 rechargable penligths (lots of peak
   current), and a 160 Watts toroid transformer for high power.
   it can be usefull to place the amp aluminium case on a heatsink...

   The powered biamped system, four power amps (square in the middle), on a large aluminium plate

The toroid transformers have rated (nominal, full time) wattages of 300+160+120=580 watts, with the subs car battery (when used) giving another few hundred watts (easily 300)  that accounts for the supply power needed (about 900 watts). The speakers themselves are another story, the woofers add up to 2x100 + 250 (500 max) + 2x25 + 2x35 = 570 W  continuous, though the pioneers of the side and rear have very high peak power ratings (up to 170 watts), the tweeters, not fed by the sub amp, are up to 2x80 (I presume for the heavy jvc domes)  2x70 (the visatons in the sides) and again 2x80 = 460 W. The main domes are used from 8 or so kHz on, so can have a lot, the rears are 12db electronically filtered from 5kHz down, that's not bad either, they are coupled with high (normal) capacitor.

The only weak point are the main mid highs (and maybe the kenwood mid lows) of the main 2x100W system: they are only 20 official watts, but then again they need only reproduce the ear-sensitive range between a few and 8 or so kHz. The heavy 2x100 Watt main amp easily blows these little paper cones to kingdome come, happened only 4 times or so already.... So care must be taken pluggin a cable live: the transient and hum immedeatly cost a few tens of euros and high squaker replacement work when unlucky. And those broken cones sound real lousy: the typical heavily used guitar speaker sound. Yack. Even worse than compression drivers.

Those mid highs appear on the other hand to have high sensitivity, so they don't need that much power for significant dBs, I might have to give them a seperate amp one day with lower power rating.

The idea of multi media on a notebook? Good!

Current powerfull enoug notebooks are quite workable machines, even though of course windows is buggy and bogus as ever, while my redhat 9 is fast and powerfull and feature laden, but not allowing the video and audio drivers to work safe or very optimally.

Here is a setup where I used a full duplex reasonable quality audio link to another (Local network connected) location, meaning there is a microphonein the one place linked with the notebook and a speaker, and there is a mike with the notebook (a fairly good one in fact, the one I used for various high quality music recordings) which conversely connects to a media player at the other computer, which is connected to the high Quality DA converter, and to the big Personal Pa System aka studio monitors and subwoofer at moderately low volume.

Given about  10 seconds delay, people can talk with eachother in this way.

Meanwhile I watched almost full time the space shuttle up til the landing, and you can see an agilent webcast on the screen, and, the other computer encodes live a satelite or cable tv channel, and the USB AD captures the audio which also can be viewed (simulaneously) on the notebook with fairly good (but not very big) mplayer window.

For this page, I was using GIMP to process images. The other machine has GIMP2, here its still 1. Disc space isn't infinite with all the other software on, it's like having a dsp, cygwin and linux and Xilinx Devenv aslready on one portable machine and then maxima, Xwindows, al kinds of media players and coders and apps, video processing, various audio software including softsynths, etc. Come to think of it, the xilinx software is removed, because it was bulky without pruning away unneeded software, and I need a parallel port which I haven't got.

A tcl webserver and the full tree of documents like on this server is ready for backup use on the notebook as well. Server (or power) failure? Start the notebook, plug in the usb adsl modem, double click the tcl server shortcut, and the server is back online!

Image from the mars rover: a 360 view flattened out from the the standpoint of the lander:

4 channel (Surround) Reverberation Unit

Based on the 500 MHz Blackfin 561 Dual Core DSP with 64 MegaByte of memory and 4 channels in and 6 channel audio out, I made a heavy enough reverberation unit, that is a studio or synthesizer machine to produce the effect of a large space on sound, like echo, which makes the sound thicker, spacier, nicer.

A good reverberation unit isn't simple, and takes up quite some processing time on a computer or DSP (Digital Signal Processor, a special kind of processor chip), and usually wouldn't be very cheap either. I owned a Yamaha Reverberation unit called the Rev-7 in a previous life, which in 1985 or so cost me $1400 as a sale:

I picked up some images from the web, with some details (NOT from the machine I had. but the same type):

That unit would still sound good, for inportant reasons, but I'm sure later machine have heavier algorithms in there, to do nicer and harder things with the sound.

Currently, I've worked with the reverb unit in the Yamaha S90, which allows also an external mono signal to be used. And as I made clear, I've made my own reverb unit from the dual core blackfin DSP EZLITE board.

And a heavy reverb it is! And a 4 output one, so it can be used to create surround signals, as I've indeed made a setup for.

No Free Software or Open Source this time!

I'll give away the scientific idea behind the algorithms though: its a quadrically distributed set of delay times and feedback factors, of in total 16 delay lines with feedback, each individually mixed in the stereo image with its own panning in a non regular way.  The main extra is that all lines are cross coupled with each other, too. Processing is from 20 bits input essentially in 32 bits IIRC for the algorithm, and 4 times 24 bits output DAC resolution, at 48 KHz (DAT rate) sampling frequency. Delay lines are up to seconds in length, making use of the 32 mega byte dynamic memory of the board, and make for the current implementations very large space impression, maybe extreme, like a plane hall, but that makes the sound with the high Q audio system very spacious.

I've made a little piece of music with the reverb in use as effect over the overall mix (made on a PC with 16 bit AD converted inputs and 16 bit DA output to the reverb), which sounds good on the high quality system with the sub on, probably better on the 7.0 config, but I didn't have the back and side channels in place, the sides are in use as a high Q TV sound system, and the biampeds are being processed to become finished. So for these examples, I also only heard a stereo mix, and of course in this case there're only 16 bits/44.1kHz (though prety good), which is a audible difference.

Examples of my reverb in practice:

   Elvis Presley short piece of "All shook up" with my reverb mixed in    (CD Q wav format, 7.5 MByte)

   Synth bass, electric guitar and S90 drums, Theo Verelst                     (CD Q wav format, 10 MByte)

The spaciousness in the first example comes across best on a good audio system, with good transient response and enough power.

The second example is me playing on my self made synthesizer with chorus unit, with a self made guitar preamplifier also connected to that chorus, and a Yamaha S90 synthesizer for drums, digitized by my selfmade Usb AD converter.

The picture above shows the dual core DSP board connected up with the AD/DA converter with USB connection. In this configuration, I used on short and one long reverb output for the left and right channel of the 'effect return' use of the AD converter. Not shown in the picture is that the output signal from the reverb is first fed into my synths 19 inch racks high quality pre amplifier with volume control, of which the ouput then is connected with the AD input, so the signal can be fixed to fit exactly in the 16 bits headroom.

One day I might have to replace the elco output capacitors of the blackfin board with MKT or so decent regular ones, like in the AD/DA converter...

Richard Stallman and Music Software

I made a video of a Stallman (the main Gnu man, who if I'm not misinformed is responsible for the excellent and famous free (!)  gcc C compiler, the basis of Linux and Cygwin) lecture, at the large Open Source conference in Brussels this year, called fosdem, where I lectured, too, though in a small room.

The video was on their server with images from the the (free) conference,  but was taken down because it was downloaded too often, and caused bandwidth problems because of course 1megabit/sec video of 10 minutes or so is a lot of data!

I'll take the chance what will happen with this server, the video is here it's over 300 megabytes for the whole footage...

I thought I'd start a thread about free musical instrument software because I could think it is somewhat expensive, and takes a bit too much space on the shelves of a serious music store and I felt taken aback by the quality of my self made synthesizer .

This is the first mail of the correspondence:

Hi Mr. Richard Stallman,

With interest I've followed your lecture at Fosdem 2005 about copyrights, little had I suspected about the amount of issues around this subject, as EE student I decades ago did an extensive group work about the subject of software patents/copyrights, and I didn't think until recently about the implications of evil forces consistently claiming everything normal and valuable in computer software and hardware.

I have a question about memory management and thought I'd ask you about it: I use a blackfin DSP (on the Analog Devices EZLITE 533 and 561 dual core board) and 'of course' also the excellent gnu C compiler on the pentium, and was wondering about eperimenting with my Xilinx FPGA/CPLD boards in combination with the DSP and some external memory. Especially the idea of memory paging and protection somehow isn't feeling right, like with the pentium I remember from the datasheets LOTs of hassle to use segment structures and pointers.

Is it possible to sum the Linux policy wrt paging/protection up in short, and is their any thinking in the compiler around this subject?

Another subject which maybe can make it in your "Political Notes"section is the question of wether _musical_ algorithms can be copyrighted somehow and to what extend, like lets say the music business sample-trouble, I sent some major (windows based) european hardware-music-synthesizer music software producers this mail:



Dear Native Instruments, IKMultimedia,

I intend to make Open Source version of simulations of vintage and
modern synthesizers,
not unlike the software you put on the market.

I was wondering if there are specific or general Copyright Issues with
the software you produce,
in the sense of there being problems with me sampling output from your
products, and alternatively:
have you had to licence for instance the Yamaha / Stanford FM synthesis
algorithms or communicate
with lets say the Hammond Fender or Sequential factories to obtain
permission to immitate/sample/reproduce
the sound of their instruments?

I've appreciated the use of the free demo programs and even the free
guitar amp simulator available and
even used them a bit to make music with, and wondered why there are no
Linux and other versions
of this kind of software which is certainly quite quality limited when
compared with the quality of
modern synthesizers like from Yamaha, Kurzweil and others but then again
many people use windows
and al large audience has been introduced to electronical musical
instrument sound impressions and

So I intend to start a number of open source products running on pentium
machines with Windows
and Linux, other types of machines which run Linux (or Unix), on DSP
(with C compiler, like
the AD Blackfin single and dual core) and in dedicated hardware
(electronics, cheap FPGA like Xilinx Sparta-3),
and wondered wether I should stay with my orignal synthesis algorithms
like my string simulator

and general sampling and subtractive and additive synthesis algorithms
or reverse engineered
general synth structures (like OpenOffice compares to Microsoft tools),
or wether this can include
Samples or electronics circuit simulations ( from 7/14/'98) ?

Of course cooperation with you would be possible (I've even responded to
job postings from NI),
but thusfar hasn't been fruitfull.

Oh yeah, thanks NI for the T-shirt I received at 2005 Music Messe, and
honestly, did you lot have
look at my BWise blockwise programming program ( ) for your latest
block programming based synthesizer software  :)   ?


  Theo Verelst



  Theo Verelst

Of course I indeed have sent that other quoted mail, but received no answer yet!

I am thanked for deciding to change my terminology from Open Source to Free Software.
Unfortunately no knowledge about memory systems ackowledged. Maybe I should write Linus...

Some Larking plates

I've downloaded a lot of Clarence Larking religeous plates because I used to have a big book of him.

Microwave weapons indeed ?

I've suggested some years ago such things, well...:

"The ADS fires a 95-gigahertz microwave beam, which is supposed to heat skin and to cause pain but no physical damage (New Scientist, 27 October 2001, p 26)." see ufodigest.

On the down to earth side of things, I with effort some time ago could find a microwave leak meter:

from conrad.

The microwave prooved ok (given radiation patterns), a mobile phone not...

Talking about Unidentified Flying Objects

Is Theo Verelst a believer in Ufos ? Well, I don't know, some of those movies and reports seem authentic enough, I don't necessarily think there is a ufo maffia feeding bogus movies to us.

This one looks tricky, its from The Best UFO Videos Ever Taken, from the Ufocasebook:

1994-Area 51, Nellis AFB, This video supposedly was bootlegged out of Area 51 by a high ranking Military official who worked at the base. It was allegedly shot from military cameras. The object appears as an orb which makes remarkable movements, and changes shape. It covers approximately 13 miles in six seconds, making changes as it goes. Whether an extraterrestrial craft or secret military vehicle, this is a great clip:

Real ?! Scary? High tech from somewhere in the HUGE universe? Possibly.

Any news in the EE scene ?

I'm sure, there always is, isn't there. Most if not all branches of sciences and engineering are less interesting or developing than electronicists.

I might be checking out (photo-copying :) ) this bookw which is from a stanford course on using Mathematica (unfortunately not Maxima) for electromagnetical wave analysis example computations:

   Engineering electromagnetics / by Umran S. Inan and Aziz S. Inan

Also, I found this goodie from the Fraunhofer institure, Germany, I went there once with some marketing guy to promote my graphics project results in their computer graphics lab.

Now they've developed a little usb stick with beamer in it!

 Fraunhofer IPMS

That would be good for front plate things, like here, I wrote that years ago.

Oh, I put my video on the internet archive:

 Internet Archive "The Story of The Neuron"

I automatically creates various bandwidth streams and thumbnails, like above in an animated gif,

The battle against software imperialism

Apart from all kinds of drivers, we now seem to need action to prevent the Microsoft Moloch from taking over dominion of the graphics cards by subdueing OpenGL, the currently widespread computer graphics (including 3 dimensional) library originating from Silicon Graphics, to DirectX om some new windows operating system variations.

See the OpenGL main site.

Lets Ask Nvidia and other graphics card/chip makers not to let that mistake of reducing graphics performance of (often Free Software) OpenGL graphics with respect to Microsoft drivers. As an example, my string simulator and Maze with tcl driving also use OpenGL. OpenGL graphics can run pretty fast.

I might be using the string simulator setup to do some music software interface in 3D even.

The spartan-3 FPGA I use might also do some serious graphics, though a bigger one could really rock. I might want to do my bezier subdivision thesis algorithms on there in realtime.

Dutch fascism or worse ?

At least that's bad. The below is from a commercial about mobile phones, and is realy ugly, and representative of the badness I think rules way too much in holland. Nobody seems to care.

Luckily I'm not in nazi germany in '39, or around such power: holland is small and relatively meaningless.

The will of certain "hidden" circuits is to rule, but as it goes holland will not help all too much, things aren't the way they think, but seeing around sure makes me sick.

I looked at the site of the solar powered car competitors from holland:

and found that there wasn't even a single Electrical Engineer on the team ( or maybe one). bad.

Like in the mobile network pushers I saw a webcast from yesterday: what a hype and snale pit of parties wanting influence and power games. Brr.

If it weren't for electrical engineers, progress and good consumer products and prices would be far out of sight.

A Maxima wiki on sourceforge !

I'll be working on this I think, a wiki is nice:

 Maxima Wiki

I've added links to my tcl / maxima (a free symbolic mathematics package like mathematica) pages on the tcl wiki,

Electrical Circuit Behaviour

A double page from Neerhof's electrical network theory.

Some simple examples using SPICE the famous (approximating) electrical network simulator, now with G(raphical) U(ser) I(nterface).

a source and a resistor

the current is 5 milli amperes, correct.

A voltage divider, giving:

3.33 volts at the output, that seems right.

All the voltages and currents in the network:

Lets see if we can get these results ourselves with the network equations and a little or more help from maxima.

The branch equations are, using the node names and current convention from the second diagram:
Lets see if we can solve these with maxima:

(C95) solve([v1-v2=i*r1,v2=i*r2,v1=5],[v1,v2,i,r1,r2]);
                                   5 %R4            5
(D95)             [[v1 = 5, v2 = ---------, i = ---------, r1 = %R3, r2 = %R4]]
                                 %R4 + %R3      %R4 + %R3

lets add the values for the symbols r1 and r2:

(C96) solve([v1-v2=i*r1,v2=i*r2,v1=5,r1=1000,r2=2000],[v1,v2,i,r1,r2]);
                                  10       1
(D96)              [[v1 = 5, v2 = --, i = ---, r1 = 1000, r2 = 2000]]
                                   3      600

and determine the aproximation of the solution of the network equations:

(C97) float(%);
(D97) [[v1 = 5.0, v2 = 3.333333333333334, i = 0.00166666666667, r1 = 1000.0, r2 = 2000.0]]

that corresponds with the spice simulation of course. In many digits...


Are there, like normally would be associated with band leaders, world famous drummers, which have realy made a mark on their music and been influencial and famous amoung at least musicians?

Of course! One of the main ones being of course mr. Art Blakey, which was well known for leading and facilitating musical happenings.

An all time famous name would be Steve Jordan, very capable and known (e.g. Simon/Garfunkel Concert in Central Park) Steve Gadd, it wouldn't be bad to check out these clinic videos if you're interested in rymths. Check out the 'simple' paradiddle, for instance. Are there any modern 'hit' drummers amoung the talent scouting hitbreakers who can actually really decently play that even?

I've been checking out which has a long list of drummers, and per name lists the bands / people they played with, and often some video.

A small but important list for mr Stewart Copeland (Police), a for progressive musicians interesting CV for Omar Hakim (of course). There's a page for Phil Collins, too.

This is a great video with 3 famous drummers,  Vinnie Colaiuta - Steve Gadd - Dave Weckl:

One of the few I think  really renewing and currently top interesting drummers, of course in the Jazz(Rock)/Fusion scene (see little discussion on the wikipedia talk page on JazzRock -- > Fusion) is mr Dennis Chambers, known from working with the Brecker Brothers, John Scofield/Mike Stern/Bob Berg/David Sanborn, Steely Dan, George Clinton, George Duke, Jim Beard (most well known progressive Jazz names).

Check out those videos! Great music. Preferably on a 10 kilowatt sound system, but my high quality big system works cool, too.

The importance of a good clock

Shown is an example project of the starter board making the powerfull spartan 3 FPGA into an ordinary digital clock which can be set over a serial cable. Also, leds can be turned on and over over terminal commands and switches read.

The design is based on the Picoblaze microcontroller/microprocessor which is programmed into the xilinx.

There is an assembler (for windows) to make picoblaze programs, which then can be turned into vhdl and combined with the code for the fpga startup in the platform serial flash.

The example can be loaded as the kit comes in, but recompilation of the vhdl isn't just possible, you need the (free) picoblaze from xilinx, and glue the whole thing together, which isn't a button press procedure. This file contains the complete, working, project:

There'll be a new spartan 3e devboard in Q3 2005, that'll be interesting, too, with a bigger FPGA but also ethernet, usb2, 4MB parallel flash, 32MB dram, and an LCD for $150 . The full value would be in the connection support examples and drivers...

Firearms, the bottom line ?

Or the final word? No I'm sure that's not the idea, but then again when you're the target it could be...

In holland, firearms cannot be freely bought or owned, you'd need some statement of good behaviour, a police permit, and first a years experience on the practicet rack of a shooting club.

That is not needed for airpressure guns, with which I had experience when I was a kid, both with a large handgun and a airriffle I shot more than a few hundred little (probably 4.5 mm) bullets in the course of the years at the end of the 70s I'm sure. That was fun, official match shooting was like hitting a card the size of 12x12 cm or so with a bull of about 2 cm diameter, which I would hit a few times every 10 shots, on a good day, from about 10 meters away!

Airguns maybe had and transported freely in holland, though not carried in public (of course), and they may not resemble a 'real' weapon, there is a list of airguns which don't pass that criterion because they look too 'real'!

For the official dutch gouvernment information, see this link from the justice department.

They even have repeating airpressure guns...

TwinMaster * TOP *     Euro 5xx,xx 

De Top is een echt compleet wedstrijd pistool met een aantal bijzondere voorzieningen. Zo is het mogelijk het wapen als enkelschots pistool te gebruiken maar ook als 8 schots revolver. Er worden drie (3) trommesl bij geleverd waar 8 kogels in passen en door de trekker over te halen komt elke keer een nieuwe kogel voor de loop gedraaid. Het wapen is voorzien van een hervulbare luchtcilinder die gevuld kan worden met 200 Bar perslucht.. Als extra accessoire is leverbaar een adaptor waarmee standaard CO2 patronen kunnen worden gebruikt. Het wapen is standaard voorzien van: * trekkerstop * Lothar Walther loop * afstelbare trekker gevoeligheid * stand voor droog trainen * compensator * volledig verstelbaar vizier * standaard grip * adaptor om te vullen * 200 schoten met gevulde cilinder.
Het geheel wordt geleverd in een kunstof koffer.