[sdiy] equalizer

[cheater cheater]

On 10/12/05, Johannes Öberg <johannes.oberg at gmail.com> wrote:
> In reply to cheater cheater:
>
>
> > Well... you may find yourself wanting to "kill" different bands very
> > frequently when playing dynamic music. Then, a simple filter wouldn't
> > work that well.
> >
> > There's much more to music than just BD :P ;-)
>
> Well, that's why the filter should be switchable between hi- and lowpass
> modes. Now, of course you would probably want a variable bandwidth bandpass
> as well, but I was trying to keep the featurelist as realistic as possible
> :-) (When I say "kill the bd" I really mean to add "or the hihats, or etc
> etc etc" but I was trying to save everybody some time...)
>  What styles are you playing?

these:
http://cheater.no-ip.org/cheater/ableton/sets/aux88_rhino_jockey/aux%2088%20+%20rhino%20jockey%20set%20Rendered%20%5blow%5d.ogg
(12 megs)
http://cheater.no-ip.org/cheater/ableton/sets/aux88_rhino_jockey/aux%2088%20+%20rhino%20jockey%20set%20Rendered%20%5bhigh%5d.ogg
(38 megs, higher quality)

8)

> I know hiphop has very different requirements
> from trance, etc. Personally, I'm into techno, acid and trance so I could
> use a bit of both, but I'm also dead set on playing from my old 300 Mhz
> Pentium 2 with DJS :-) Therefor an external mixer is the only option for me.

Check out Ableton Live. It's really fast and efficient. It might just
run fine on your PC, and there's a demo, too.

>
> > Who said anything about fixed crossovers? :-)
>
> Hey, that mixer of yours is going to look like an ARP2600 :-) Anyway,
> indeed, an 24 dB/oct eq with tweakable crossovers and -oo kills would be the
> most versatile, I'm just concerned about the usability aspects,

Worry not, I've got the whole UI thought over already ;-)

> and the
> hardware complexity. If you're going the analog route, I'd say the latter
> should be your main concern, especially if you're not experienced in the
> field...
>
> > Also, buttons for killing bands are nice too. And they're going in my
> > mixer for sure :-)
>
> There exists these nice 3-position switches which are
> (locking)ON-OFF-ON(temporary) which bounces back to OFF from the lower
> position. Perfect for kill switches imho.

link? :-)

> > uCs are real cheap! c'mon
>
> Yup, but there are lots of other costs, like development equipment... Not to
> mention the labour!

You can make a PIC programmer out of a pack of chewing gum and several
paper clips... 8P

>
> > That's how the P&G faders have to be used anyways. The ones used as
> > crossfaders aren't even sold as audio-taper, I think.
>
> Sorry, I misunderstood; I guess I don't know what P&G faders are.
>  Anyway, if I'm alowed to dream some more :-), there is the option of making
> an optical crossfader with a lamp and LDR's (or LD-something-else's), that
> would have no wipers at all. I don't know if these exist already; I haven't
> seen them, but then I'm not an active DJ. I don't know about LDR
> sluggishness issuess either.
>

P&G faders are magnetic.
Read up on http://rane.com/ttm56.html for example (they make nice,
durable mixers!)
This is how they test them:

http://rane.com/xfader.gif

Magnetic Fader Testing
The engineers at Rane employed a sewing machine to test the durability
of the magnetic fader. Each stroke generated one count. We have it set
to apply a million strokes to the fader every day. We tested 13
million strokes before we got tired of hearing the darn thing, and the
fader shows absolutely no wear or degradation.

Judging from what experienced DJs say, like Grandmaster Flash, those
really barely ever show wear or degradation.

> > No way!
> > DSP is no fun. DSP costs a lot. DSP breaks. DSP doesn't have an analog
> > sound. DSP isn't easy to change on your workbench. And I'm not
> > interested in learning DSP.
>
> I don't know about the fun, but the cost is probably about the same these
> days. And why would it break? I also think that analog sound is quite
> overhyped, especially in an application like this, since the only thing it
> could add are phase-errors in the crossovers - which would do no good to the
> sound. And it sure is easier to reprogram an EPROM!
>
> But then again, if you're not into DSP, thats reason enough. I'm not either
> in this case, but then again, I would be happy with something simple (my
> current mixer doubles as a pink noise gen). However, I think you would
> probably have to drop the digital control dreams, or it gets way too
> complex.

Hmm, making an EQ that doesn't sound like crap ought to be pretty
difficult, too.
I remember the first VST filters, they sounded like speak&spell 8)

>
> There's always use for a simplified first version when it comes to this kind
> of projects...
>
> > > Digital control over
> > > analog filters seems to me to be a very cost-ineffective way to do
> things
> > > these days.
> >
> > Why?
>
> Because microprocessors are so fast these days (hey, even a $5 Atmel is
> faster than my first PC!), if you already put one in there you could just as
> well save on the filter parts by doing it in DSP. Look at the AVR synth
> project, here on the sdiy list, for inpiration.
>
> > No - that's exactly why I want an analog mixer.
> > With VSTs, even with ASIO2 you still realistically get 10-20 ms of delay.
>
> Isn't that only because of MIDI? Everything else is dependant on system
> settings, isn't it? IIRC, the Behringer controller runs via USB, and should
> have no real latency. If I'm wrong on this one, I'm sure there is some other
> controller.
>

The delay comes from the fact that the audio has to be processed by
the software. Which, on a semi-complicated setup with Ableton Live,
might take that long (even if you only use half your CPU's power...)

> > Actually, that's where I would do your "set up the permanent EQ for
> > the track" part. You can get VST equalizers in much better quality
> > than you'd be able to build with any sane amount of time and effort :P
>
> Yup, good idea. Run a multiband compressor here, and never worry about
> anything.
>
> Lets dream on :-)

Dream on?
I'm not letting go till my dream mixer is in my room 8)

> Before we all end up in an analog vs digital fight (...no?) I feel compellled to add
> that if your main goal is to get a working solution to the initially stated problem,
> you are probably better off working some overtime and buying a new computer
> and other sorts of readily available hardware. Especially if you have no previous
> analog design experience. For starters, you'd have to get a lot of things just to
> be able to build the thing, like a soldering iron, an oscilloscope, lot's of parts
> (they are getting expensive!). Then theres a steep learning curve, and thru-hole
> parts are dissappearing. Then add the labour cost, and almost any minimum
> wage job gets you better results vs. effort.

Don't worry 8) I soldered things people wouldn't believe! Well, you
guys might. But I'm talking about mere humans here.
I've searched for a few years for a mixer that'd be what I wanted and
I couldn't find it. Heck, there's nothing even in the same ballpark 8(
Steep learning curve = functional analysis lectured by a Taiwanese
dude trying to speak polish ;-)
Thru hole parts - I want to use SMT anyways :)
for 'scopes and other specialties I think I could always go to my
university's labs... they have some nice stuff there it seems!
labour cost is free... my time is worthless. 8P





not quitting.

Cheers,
D. 8)