eee I/O

Digidesign makes the world's best digital audio workstation: Pro Tools. But, as with any product, there are things that are wrong or just weird.

One that my students encounter quite often is the difference in I/O settings between Pro Tools LE with a 003 interface and Pro Tools HD with 96I/O interfaces. The default I/O for the 003 has sensible labels: "Analog", "ADAT", and "S/PDIF". These correspond to the three kinds of inputs and outputs available. The default I/O for HD, at least with 96I/Os, is to label each interface "A", "B", and so on, and then label each interface's 16 inputs and outputs with numbers from 1 to 16. That seems quite logical except that connections 9 to 16 are via the ADAT lightpipe port, not analog connectors.

Of course, one is free to customise I/O labelling and configuration. If we're using HD (the "professional" version), we're grown ups and should be able to cope. But I still don't see the harm of labelling the different types of inputs according to their type.

Calrecs arrived

They arrived! I've played with them a bit for a couple of weeks.

Yes, two Calrec PQ2647 modules have arrived, nicely racked up by Rob Squire at Pro Harmonic. The other pair is with Mixmasters for evaluation.

Rob has set them up with separate mic and line inputs, switchable with the original LINE switch. From there one can use the EQ section (more on this below). The auxiliary send section does not work at all. I had thought of maybe using a send to get multiple outputs or a final trim control on the output, but it is apparently quite hard. Rob says there are a number of switchable options on the circuit board (accesible via little DIP switches) which have to do with the order of components in the signal path, mute control, and so on. That's OK. I can live with them just being mic pres and EQs.

I played with a ribbon mic and the EQ section straight away. The mic is a Speiden SF12, but one purchased before Royer started manufacturing the design. The mic is beautiful: not a great high end but the best stereo imaging ever (it is a Blumlein configuration).

I've never had a quiet enough mic pre to use it well. All cheaper mic pres, based on SSM2017 chips and the like, are not quiet enough at high gain settings: wind the attached trim pot past the 3 o'clock position and they hiss. The first thing I notice was that the Calrecs don't hiss really at all. Even at 60 dB + 15 dB trim (a whopping 75 dB), they're pretty clean.

The EQ is great. Well, perhaps not great like certain pieces of classic gear, but good. There are low-pass and high-pass filters, each with three selectable frequencies. The high and low shelving bands each have two selectable frequencies and an unspecified amount of boost or cut. It's at least 12 dB and may be 15 dB. The mid band is a bell curve and has the same gain and variable frequencies between 200 Hz and 8 kHz. The EQ certainly sounds very musical and is very useable. The switchable frequencies are very sensible.

I tried it out on a piano: OK, but since the instrument was not great, it was hard to tell. Certainly the pres gave me what I expected given the mics (AKG C414s). Then I used it on a female vocalist with a fair degree of "air" in her voice. A bit of mild compression dulled that a bit so I dialled in a couple of clicks above 5 kHz. The top end shimmered! Since the C414s were the best mics available, that was what we used. They're too neutral sounding to be a good vocal mic, but through these Calrecs I'd reconsider!

Mixmasters engineers tried them as a line-level EQ and a mic pre. They were a bit non-descript but said they were decent. Mind you, those chaps are surrounded by Avalons and vintage Neves and the like. One wouldn't expect a cheaper Calrec channel strip to do the same thing. So, all in all, I'm very pleased.

Mixmasters is sending the second unit back to me. So if you want a couple of decent mic pres and EQs, contact me before they go on ebay or Mixmasters gets an interested buyer.

PHP scope and get_object_vars()

I've been trying to use the PHP function get_object_vars(). The description of the function says that...
Gets the accessible non-static properties of the given object according to scope.
Well, sort of. Take this code for example...
class Foo {
    private $priv = 1;
    protected $prot = 2;
    public $pub = 3;
    public function showFromWithin() {
        echo 'From within: ';
        echo "<br />\n";
    public function showFromOutside($obj) {
        echo 'From outside: ';
        echo "<br />\n";
    public function showAnother() {
        echo 'Another: ';
        $o = new Bar();
        echo "<br />\n";
class Bar {
	public $a;
	protected $b;

$foo = new Foo();
$faz = new Foo();

Here's the result:
From within: Array ( [priv] => 1 [prot] => 2 [pub] => 3 )     //foo
From outside: Array ( [priv] => 1 [prot] => 2 [pub] => 3 )  //foo
From outside: Array ( [priv] => 1 [prot] => 2 [pub] => 3 )  //faz
Another: Array ( [a] => )  //Bar object
I would have thought that calling from outside the object would result in only the public class variables being listed. Maybe in the second case, where an instance of Foo is looking at itself, it works as expected. But when one instance of Foo looks at a different instance of foo ($foo2), shouldn't the private and protected class variables not show? I don't get it.

Mic pre fever

I've got a thing for Calrec modules.

For the uninitiated, there are certain classic pieces of gear which appreciate in value over time. There may be a number of reasons: fashion, quality of manufacture, reliability, or a certain "quality" of being. Audio gear is no different. Amongst the hi-fi buffs, old Marantz and Dynaco amps, Linn turntables (among other items) and Quad electrostatic speakers are sought after because they are classic designs and sound good. (You do have to wonder about hi-fi fans' claims, though, when they start talking about the sound of cables. If only they knew how many pieces of wire, electronic components, and connectors their favourite recordings had been through on their way to... insert hi-fi format of choice here!)

For professional audio engineers there are a few names to watch out for: Neve, API, Pultec, Fairchild, Teletronix and Urei. (There are of course others.) In particular, certain microphone pre-amps -- sometimes combined with equalisers (filters giving tonal control) -- have a certain quality widely recognised for endowing audio signals with a distinctive "colour". Some compressors too. Many of these are components which were originally part of mixing consoles.

Rupert Neve's classic designs are good examples. The consoles produced in the late 1970s and early 1980s were modular with different functions being performed by modules that plugged into a frame. Neve's mic and line amps and EQs are sometimes now more valuable than complete consoles whence they came. That may be changing now as there are fewer and fewer of these consoles, but in the last 20 years a number of owners realised that they could make more money selling individual modules than the complete console and so there are a lot of them around. The problem is that most of them are racked up and in working studios and it's hard and very expensive to get hold of them.

Certain manufacturers and models attract more attention than others. So one sometimes finds lesser-known units that may be just as high quality. Calrec is one such example. As I understand it, they started as an "audio" club and manufactured some BBC-designed equipment. When Neve couldn't fulfil all the orders, the Beeb turned to companies like Calrec. Some of the Calrec modules are considered to be as good as Neve 1073s or 1084s but are not as expensive. (They are becoming better known.)

Hard-up engineers like me are always on the look-out for bargains. Over the years I've picked up a few: an Aphex 622 expander/gate for 30% of the retail price, some Audix mics for a song, a Yamaha SPX990 for much less than the typical second-hand price at the time. Other items may be inexpensive but are surprisingly good. The early Behringer compressors are, in their functionality and response if not their actual sound, a knock-off of a dbx 160. They actually use THAT Corporation VCAs. I've heard a story that Joe Malone of JLM Audio buys Behringers by the bucket-load because he can't buy THAT VCAs for anywhere near as cheaply. Anyway, the late-model Behringers feel very flimsy (you could balance them on one finger without any discomfort, but, as with any potentially controversial claim on the internet, I'll say that Your Mileage May Vary!). The early ones are built like battleships. OK, the non-adjustable attack and release times on the limiter section make the latter unusable but the compressor section works just as you expect it to and it sounds all right.

Well, I've been hitting ebay too much for my own good lately. I picked up a Lexicon PCM60 reverb unit (c.1984). No, it doesn't sound like the Concertgebouw in Amsterdam. You can now buy software that does! The boffins have actually measured great rooms and modelled them in the reverb algorithms. The Lex isn't realistic and it's very simple, but it sounds good and a little funky.

I also got 4 Calrec modules from a guy in Oregon. They come out of a Calrec Compact console and include a mic pre, 3-band EQ plus switchable-frequency high-pass and low-pass filters, and 4 auxiliary sends. Unlike the larger consoles, almost all the channel strip functions are in the one module. I thought to myself: if the gear is in good condition, how bad can it be? So I took a punt and bought four, even though they're not the better-known modules. I'd like to get them racked up in pairs and sell one pair to offset the cost.

Just lately, someone was selling a DL1656 compressor. This is better known. And then a crowd in Northern Ireland was selling two PQ1347 mic pres and EQs. Mixmasters in Adelaide is selling a racked pair of an earlier version of the same for $3500. Maybe that's too high because they've been listed for quite a while now. But I think I got a bargain.

So bit by bit I'd like to get them racked and keep some and sell some. I may not make any sort of profit but if I can substantially offset the original purchase price and racking cost, I'll have a few nice mic pres and be happy.

Twitter and all that

Oh Jason, I am so with you.


A vanity publishing venture of David Rodger, sound production teacher and wannabe PHP developer