Wednesday 30 March 2011

DIY PAD cable

I was having a few difficulties recently when trying to record drums with the C24 in studio 2 - even with the mic gain turned all the way down, we were still clipping the inputs to Pro Tools.

On the day of the session I worked around this by using external mic pre's, but I wanted a better solution.


A little bit of research and soldering later, and I turned up with this:


(at the other end of the lead is a standard XLR female connector)

The circuit fits quite neatly into the chassis of an XLR male connector (it's important to make sure it goes on the desk input end of the signal, so I'd avoid wiring this into a patch cable), and does the job quite nicely.

I made the cable about a foot long, and you simply daisy chain it to the end of a mic lead. They've turned out to be so useful, I'm in the middle of making another half dozen of them.


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Friday 18 March 2011

SE Voodoo Ribbon mics - active vs passive

I remember when SE mics came out, we all assumed they were just another company ripping off classic European mics for budget prices. Turns out we were quite wrong! SE have introduced some totally new concepts (take the Reflexion filter for example - why did nobody think of this before?), and developed their own technology - the capsule design on the Voodoo ribbon mics being a case in point. Designed by Siwei Zou (the CEO of SE), it extends the hi frequency response of the mic, giving us what is said to be the first ribbon mics with a 20Hz to 20kHz frequency response.

I managed to get my hands on both the Voodoo VR1 and VR2 mics, so I though I'd check them out, and see what the differences are between them.




The two mics have identical capsules - the VR2 is the active model, so has an extended body to fit the amplifier circuitry (Careful putting the two up against each other though - the magnets are strong enough to stick them together!). Both look pretty unusual - but at the same time, pretty cool. As with all ribbon mics, it's essential to treat them with care, so there's a small drawstring bag included to cover the capsule when moving the mic (the saying with ribbon mics is "bag it on the stand" - simply waving the mic though the air can be enough to damage the ribbon - it's only 2 micrometers thick!). In practice, the bag is a little fiddly, so it might be worth investing in something like an iPod sock to do the job.

The Test Setup
I decided to put the ribbon mics to a classic purpose - guitar amp recording. I used a Fender Strat (Rory Gallagher model, set to neck pickup), and a Vox AC30. I let the amp warm up for an hour, and played around with the tone settings until I found something I liked (which honestly doesn't take long with that set up!).

To keep the performance consistent, I DI'd a guitar take into Pro Tools, then used a Radial Pro RMP re-amp box to feed the performance back into the AC30 through a Soundcraft Reims console.

After setting up the passive VR1, I played around with the mic position until I found a sweet spot. I quickly recorded the re-amped performance, then swapped over the VR1 for the VR2, positioning the capsule in as close to the same spot as possible.


The Results
Both mics sounded great - I have a couple of guitar tracking sessions coming up soon, and can see them getting quite a lot of use. On paper, both mics have the same frequency response, so I was surprised to hear as much difference between them as there was.

The passive model definitely picked up more room sound, and the active model had a fuller low end. On balance, I'd choose the sound I got from the VR2 over the VR1, but only just. The only thing I can put this down to is the mic pre settings (the VR2 has a much higher sensitivity, so although I took care to match the record levels, the mic gains had to be significantly different).

The oddest thing I noticed was that the mics are wired phase-opposite - definitely something you should be aware of when putting multiple mics on an instrument (and simultaneously using a ribbon mic with an SM57 is pretty much a standard guitar recording technique). OK, simple enough to fix, but a bit of an oddity all the same.

The Final Word (for now)
I'd like to put the VR1 to test with a few different mic pre, just to see the kind of difference that makes (I'll try this over the next couple of weeks), but if you have a lower end interface, it might well be worth stretching your budget to the active model, and letting the inbuilt mic circuitry take the strain. However, whichever of the two you go for, you won't be disappointed in their performance.


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