A little podcasting

So this past Monday I had the privilege of being on The Home Recording show with John Tidey and Ryan Canestro.

Here's the link: http://www.homerecordingshow.com/2012/06/show-172-mixing-with-a-subwoofer-kickstarter-and-more/

I've had this podcast at the top of my list for a good little while now, and it was great fun to get to jump on and talk audio with those guys.  I actually catch quite a few different podcast on a regular basis, an THRS always jumps to the top of my list when a new one comes out. 

I dig this podcast because it's got a killer structure (Ryan and John read all of the reader's comments and joke around to start the show, then they do segments) and the guys are knowledgable, fun to listen to and the running inside jokes remind me of the antics that happen on my fav sports radio station (the Ticket).

The whole experience was super chilled out and fun.  John asked if I wanted to do a show, I said sure, he pinged me one day and asked if I would jump on, and away we went.  Because I've been a fan of the show for a while, it felt very comfortable just hanging out with a couple of guys that I feel like I already know and talking about whatever.

So head on over to their website, subscribe to the podcast, buy through their amazon link, etc.  This is a good show to support.

Good times. 

recording my moto: the VTX1300

My motorcycle has been sitting for too long, so I'm going to sell it.

Anytime an audio person makes the decision to sell a vehicle the first question is always "have I recorded it sufficiently?"

In my case the answer was no.  I'd recorded the bike before, but I had never really given it the full treatment, so I rolled it to work last week and set about recording it after hours but before the sun set.

This bike is a Honda VTX1300 with aftermarket Vance and Hines big shot exhaust.  Honda's VTX line has a big, beefy transmission that clunks loudly when you drop into and out of first, and the big shot exhaust really does that distinctive chopper cruiser sound well.

Outside of those two main elements I didn't see much else on the the bike that I felt as though I could record cleanly and at speed.  Tires were pretty out of the question, as was any noise that my feet made on the gear kicks.  My plan was to find the best compromise of drafting placement and proximity to the transmission/exhaust for the onboard mics.

Drafting is a huge deal anytime you want to record a vehicle going faster than about 10mph.  Drafting is the concept of placing mics within the shape and structure of a vehicle in a way that minimizes direct wind exposure when the vehicle is in motion.  No amount of wind protection will stop an 80mph direct exposure to wind, but proper placement will allow for minimal wind protection to be sufficient even at that speed. 

Motorcycles are a little trickier than cars and trucks when it comes to this because they have less surface area on which to mount things and the bodies don't divert nearly as much wind around them, so drafting options are more limited.  This bike is pretty sporty and stripped down, which limited my drafting options further.

I decided to go with the following mic placements, wrapping each mic in a few layers of a cut up T-shirt:

• Line Audio CM3 behind the shock and near the exhaust
• Line Audio CM3 behind the engine block and aimed at the transmission
• Sanken COS11 lav behind the engine, under the seat for general engine bite
• Crown PZM 6D behind the license plate and near the exhaust.

here are the placement pix and isolated tracks of a 60mph run.

 

Of all of them, I feel as though I could have walked away happy with just the combination of the PZM and the Lav (which I almost didn't put up).  Both mics capture a ton of detail, and the PZM in particular felt like the gold standard of someone behind the vehicle moving at speed with a mic aimed right at the exhaust and no wind.  That mic just had tons of low end, and got the quick transient nature of the cylinders just right.

The CM3s acted a little wooly and took on the most wind of all the mics, though they were certainly still acceptable and in the end gave me some interesting lower mid punch that the other two mics weren't picking up.

When they all came together I just about came out of my seat because I heard for the first time a representation of what it really does sound like to be piloting that bike.



Everything is there.  The transmission kicks when I'm climbing the gears,  the whine as the engine lets up, the fluffy kind of release in the exhaust, and all of the power of that bike feels like its there.  The only thing missing is the wind, which is a pretty crazy experience given how intimate I am with the sound of this thing.

Its easily one of the best recordings I've ever made, and I feel like that PZM near the exhaust is going to be my new secret weapon when it comes to the exhaust portion of vehicle recordings.  That thing took zero wind behind about 4 layers of cotton T-shirt even at 80mph on the highway over a 10 minute ride I did the same day.  It was kind of magical.

I had my intern out helping me on the shoot, and he captured a perspective that I'm less familiar with: the exterior by.  He was running a 416 in a blimp and was tracking me as I passed.  These recording also came out great:



In all I got a full compliment of sounds from the favorite moto I've ever owned in about 3 hours of recording (including setup and teardown).

Things never seem to come together this well, so its important to sit back and appreciate it when they do.  Feel free to use these recordings in whatever context you see fit.

Enjoy!

quickie M/S mic shootout

Here's a quickie mic shootout I recorded today.

I wanted to test the new ribbon mic in a setting that would naturally compliment it.  That mic likes loud bright things because it has relatively low output and a smooth darkness to it that kind of tames things that can get shrill or scratchy.  It also has low end for days.

As such I figured a good garage door impact slam would do the trick.

I've only got the one mic, so I decided to run it as the figure eight of an MS config with my trusty Line Audio CM3.  That line audio mic has a similar personality to the ribbon (lower output and a darker sound) so I figured the two of them would get along great as an MS pair.  I also had a cloudlifter in line on the ribbon for impedance matching and signal output purposes.  I pretty much don't run that mic without it.

I also wanted to test this rig out against a known quantity, so I put up the workhorse Audio Technica 4050s in an MS pattern right next to them.

The results were pretty interesting.





In many ways the results were as expected.

The 4050s were significantly brighter than the CM3/Ribbon combo, and tracked the transients more closely.  They also sounded cleaner and more clinical, which in some situations is a good thing.  With that said, they still had significant low end punch and didn't sound thin at all. 

The CM3/Ribbon combo was much darker, but the difference really was in how thick this combo made the low mids sound.  There was just tons of punch down there that was very satisfying.  This kind of rig takes EQ very well, but even when I experimented with adding some high end the predominate characteristic was that huge low mid presence.

The difference in the high end was most apparent when I opened the garage door and let the sounds of the birds and traffic from outside through.  The 4050s just opened up and revealed all of the damping that the doors were doing to the outside world.  The CM3/Ribbon combo kind of hung back and let the game come to them.

Given how these two signatures seemed to wrap around one another I figured I'd just add them together.  When overlaid against one another I got this huge thick sound that still had all of its detail and clarity.  Its a lot of mics to put up for one sound, but the end result sure seemed worth it.

Here's a spectrogram of the impacts, with the 20k line marked.

Feel free to download these sounds and use them in whatever context you see fit.  Enjoy!

building a ribbon mic part 2: listening test

One of the best pieces of advice I got after building my ribbon mic was to test it through different preamps (thanks John Sanacore).


At my house I noticed some RF buzz, which is actually typical because my house is an RF nightmare.  I decided to ping the designer, Rick Wilkinson, and ask his advice.  Rick responded almost immediately with a comprehensive and detailed troubleshooting list that was incredibly helpful.  The problem ended up being a faulty cable, but I learned that the brass grille was part of the faraday cage from the exchange.

I took the mic to work the next day and ran it through the John Hardy M1, but wasn't very impressed with the sound.  It actually had sounded louder and clearer at the house through the RF buzz.  I then plugged into a sound devices pre similar to the one I used at home and was much happier with the output.  I also began looking into getting a cloudlifter to help with impedance loading and output gain from the mic.  My research was showing that ribbons in general tend to want pretty loud sources, but I have designs on using in more delicate situations and needed get it up to par there.

I emailed Rick again, and again he was again super responsive and detailed.  here's a quick excerpt of what he said to me regarding my experiences to this point:

High end response is determined by the input impedance of the preamp.

Generally, a higher input impedance delivers better high-end response in ribbon mics.  A REALLY high impedance preamp (10k ohms or higher) like the AEA TRP, or my DIY Preamp Kit made especially for my mics (available in another month or so) will really help the top end.  

"loading" is the term for the interaction between the output impedance of a microphone and the input impedance of the preamp.  The correct description of this interaction is something like: "The microphone has to work harder, if the input impedance of the preamp is lower."  This makes sense if the microphone is overly-simplified to a current source: It takes more current to drive a low-impedance load.

A simplified version of this is:

A lower input impedance requires the mic to work harder to deliver a signal. Thus, low-energy, high frequency soundwaves do not get transferred to a low impedance preamp as efficiently as to a high-impedance preamp.

You can see this interaction in my own design, by looking at the impedance curve on the specification PDF on my website.  As the measured frequency goes past 10kHz, the impedance soars - literally off the chart - lowering the effective output of the mic in those frequencies.

That's probably why an Austin Mic through your Hardy sounds like it does... I just looked at the specs, and their Jensen input transformer is 150 Ohms. The current flowing through the ribbon is trying to keep the foil inside the gap, not allowing it to move with low-energy, high-frequency soundwaves.

Supporting that theory, the Sound Devices input shows an input impedance of 2000 ohms - 13x higher than the Hardy.  Better high-end, right?

 And of course, he was correct.  The thing that the cloudlifter provided me was a good impedance load (3000 Ohms) in addition to the extra 20db of gain.  Here's a quickie listening test of the mic through the three different configurations.  All of this audio is 100% as recorded - no gain or eq adjustments of any kind. Note that the gain settings are described in the recordings, and in the first two examples its all the way open, and in the last clip its around 12 o'clock.



So, the impedance loading clearly makes a huge difference with regards to the tonality and the output level of the mic.  IMO it's not very usable straight into the John Hardy M1 unless you're talking about very loud and bright sources, but the sound devices pre and the cloudlifter/M1 combo make the mic much more versatile.

So, given an input chain that I liked (cloudlifter/John Hardy M1) I did a few more little tests with bright, transient things and the mic performed extremely well.



To my ears the mic is certainly mellower on the top end than my usual LDC, the Audio Technica 4050, and its certainly got its own personality.  It handles transients like a dynamic, which is to say that its a little jumpy on the loud stuff and it drops off on the low level stuff more quickly than a condenser.  To me that generally means that its not going to catch as much detail on a highly transient source, and will be happier with something relatively consistent.  It's also got low end for days.

With all of that said, that little strip of aluminum leaf I bought at hobby lobby, cut, corrugated and mounted into that chassis is clearly capable of capturing frequencies well above 20k, which is impressive.  I only ran the instrument tests at 44kHz, but check out how easily it handles all of the frequencies up to the top of that 22k spectrum.

This is the spectrogram of the instrument file linked above:

And here's the zoom in on my voice slate and the tambourine.

This mic is clearly capable of capturing ultrasonic frequencies.

I'll run another test soon where I use it as the S in an MS config on some thick metal movements and see how she does.

building a ribbon mic: part 1 - construction

Way back in July 2011 recordinghacks.com did a $60k ribbon mic shootout, and I had the opportunity to listen to a wide variety of ribbons on different sources due to the hard work of those dedicated pros. 

Around the same time, I was making a big personal aesthetic shift away from bright and quiet mics and towards warmer mics with more character - especially for recording bright and transient sources.  I knew then that I had to have at least one ribbon in my collection.  The problem of course, is that ribbon mics are expensive and I only spend so much money on gear any given year.

The solution to my problem ended up being the DIY Austin ribbon mic.  I don't have a ton of DIY experience, but I can work a soldering iron competently, so I felt like I'd have a shot at building the mic successfully.  I googled around a bit and found a few people that had built the mic with relatively little experience. 

In the end, the audio samples and the $200 price tag had me sold, so I took the leap.

Initially I didn't know exactly how much pride of ownership I'd feel or deserve after assembling the mic.  I certainly wasn't the one who designed it or even who sourced the materials.  In my mind, I was just going to essentially step into the shoes of a mic plant assembly line worker, so how would I feel when the mic that I built with my hands was complete?

Within a short time of the online purchase I had full detailed instructions in my inbox and a link to a series of videos detailing the construction.  It was great to get this in my hands early, as I was able to review the videos and instructions a few times before the mic even arrived at my door. 

The instructions and videos are not high on production value, but they are entirely informative and thorough.  I never felt wanting for instructions or reasoning in assembling the mic.

Once I had cleared out my workspace I set about building the ribbon motor, which meant gluing the two powerful rare-earth magnets onto the brace with a plastic spacer holding them against the walls. Next was to glue the conductive sheet to the edges of the brace and solder the lead wires to it.

All of that was the easy part.

The trickiest part was cutting and mounting the ribbon.  The ribbon in these mics is made from aluminum leaf whose thickness is measured in millionths of an inch.  It is incredibly fragile, and the process requires cutting a 1/4" ribbon with an exacto knife and then corrugating it with a wooden dowel inside of a sheet of paper to make it springy.

I shot a little timelapse of my building the first part of the mic, but the camera ran out of space as I tried again and again to cut and mount a proper ribbon into the ribbon motor.


first part of assembly-austin ribbon mic from rene coronado on Vimeo.


The kit only comes with one sheet of aluminum leaf, and by the end of the evening (and the timelapse) I had ruined all of it.

Undeterred, I went to hobby lobby the next day and bought more.  I spend the next evening ruining even more, but with every attempt I got further and further into the process before making some fatal error.  At one point I had cut and corrugated 3 consecutive ribbons with my exacto knife in a row, and was only breaking them in the mounting process, so I knew I was getting close.

Finally somewhere in the middle of my third sheet of leaf I managed to get a proper cut, mount and tension and I was so excited I was texting pictures to the wifey. 

With the ribbon motor built, I soldered the screen together and assembled the rest of the mic.  A quick test through a sound devices mixpre confirmed that I had a working mic, and I went to bed exhausted and happy.

So what kind of pride of ownership did I have at the end of this?

Tons.

Cutting and mounting that ribbon required a fair amount of skill, and that skill had to come through repetition.  It really took some stiking with it to make the thing work but knowing that I cut and mounted the ribbon that's translating the air movement into the sounds I'll record through it offers a very high sense of pride and ownership of the process.

With that said, Rick at Austin Microphones has put an incredibly high amount of research and development into this project, and I'm positive that even though I spent a few long evenings putting this mic together, Rick has invested far more hours than I have into the creation of this mic. 

In part 2 I've put up some listening tests through different preamps and with a cloudlifter in line.  The impedance of the preamp actually makes a huge difference on these mics, and I'll share some advice that Rick gave me in some subsequent correspondence regarding that and other things.

In the meantime, here's a much better timelapse of Rick building the mic to completion and testing it over a 2 hour period.


 

a short love letter to Mike Monteiro

My phone is constantly loaded up with podcasts done by people I enjoy listening to.  Many of them are audio related, some are not.  But some of them fall in between, and the Lets Make Mistakes podcast on the Mule Radio Syndicate is one of those. 

First a little background - LMM is hosted by Mike Monteiro and Katie Gillum of Mule Designs.  Mule Designs builds websites, but they podcast about design which is what interests me.

Mike is one of my favorite types of internet people.  He's intelligent, opinionated, a little eccentric and not entirely full of himself.  Matt Gemmell and John Gruber also tend to fall into that category.

With that said Mike is more on the eccentric opinionated side of that scale, which is why I love his stuff so much.  He also gives excellent advice to audio guys about the business and process of design just about every time he opens his mouth.  My first exposure to him was this video (which is NSFW if your job frowns upon frequent cursing)


so there's that.  The podcast actually doesn't have that much cursing and it rambles a bit more than a formal presentation like the video above would, but its very worth it nonetheless.

The episode that inspired this blog post was a recent one called "Another Stupid RFP process" There's just so much gold in there that it's difficult to do justice with a quick blurb, but I'll try:

An RFP is a Request For Proposal and is typical of agency workflow.  In it, multiple vendors will make a pitch to work on a specific job at the same time, and the committee needing the work done tends to decide who gets the job based on a number of metrics the derive from the pitches that are made.

It's also an awful awful process, and Mike and Katie just do a masterful job of taking down the entire RFP mentality.  In the audio world RFPs are common to music composition (even if they aren't labeled as such), and so many musicians make their livings writing and pitching music for free to committees on corporate boards.  Its also a dynamic that comes into play when pitching one's self as a sound designer for a project.

In the podcast, Mike illustrates that a good working relationship requires both give and take, not just give - and when you enter into a relationship where you'll be making emotional decisions you have to be able to figure out if you can work together. 

"it's more important to have people who can work together than it is to have like the smartest people possible" - Mike

"at my most pessimistic I think all of that stuff is an elaborate trap to make sure that nobody can be blamed if the project goes wrong" - Mike

"There's a huge difference to the relationship you end up having with a group of people, or even just the conversations you have when you're being called a 'vendor' and when you're being a design studio" - Katie

"There's something about the process that makes it seem more like picking a commodity than on creating a relationship" - Katie

"A 'vendor' is somebody who sells you things, and its the things that have the value.  A 'partner' is somebody who works with you, and its the working together that has the value" - Mike

"If you show up at an initial presentation with comps of what you're going to do for that company's site you are an idiot.  You are an idiot.  And you should be laughed at and you should be thrown out of the building and you should never get to call yourself a designer again, because what you're doing is making shit up out of your head and putting it in front of a client irresponsibly and passing that off as design work.   You have no idea what they're trying to solve, you have no idea what their internal mechanics are, you have no idea where they're trying to go in the next two, three years.  And yet somehow you've pulled a solution out of your ass.  And then you have the balls to take it into a presentation and present this as 'this is how we think, this is what we think you should do'" - Mike

"I think 'let me tell you how we approach design, ' and you can actually say 'let me tell you how we'd approach your problem'" - Katie

"This is a goddamn endemic with designers.  They are afraid to do the thing they know is right...I'll be sitting with a designer and going over some work and it looks dead.  It looks like they don't know what they're doing.  They're pushing their food around their plate. There's no joy in it, they're not trying things.  And at some point they'll say something to the tune of 'well if I were doing this my way...' and I'll just say nothing and let that silence hang like a Mike Daisey apology interview, and eventually they'll realize what they just said, and they'll get back to work." - Mike

"It's a really sad form of self-censorship, and it kills designers because they do crap work, and its also incredibly unfair to people who hired you to do this work because they hired you to do the best work that you possibly can, and instead you think they could think of." - Mike

anyway, I could transcribe the whole episode or you could just take my advice and listen to the podcast.  Also, don't follow @Mike_FTW on twitter, its a little too erratic.

-enjoy!

contact mics and guy wires

Everyone knows that Ben Burtt made the blaster sounds in Star Wars by striking guy wires and recording them with contact mics.

Countless others have done this as well, but I needed to test out some new gear so I figured I'd give it a go.

Gear included my recently acquired Jez Riley French contact mics and my new Sound Devices mixpre that I bought to use as a front end for my PCM D50.

The entire signal path was:  doublesided carpet tape --> JRF contact mics --> Hosa MIT-129 impedance transformer --> mixpre mic ins --> mix pre tape out --> PCM D50 line in.  These recordings are 100% unedited (including gain changes - this is the level I cut them at)

re: contact mics, Tim Prebble has an excellent post outlining the entire process, but the long and the short of my setup was that the impedance transformers were absolutely required to get all of that low end out of my rig.  This is because contact mics are high-z sources and the mixpre is a low-z preamp.  In the past I've also had good luck running straight into an H4 with other contact mics, but I suspect that's because the H4 takes hi-z inputs by design.  With that said, I've never quite recorded low end like this with contact mics to date, so I was very happy with the result.

Also, I laughed a little when I saw that the BBC went into an anechoic chamber and recorded a few very tiny insects using these exact contact mics and preamps.  It's quite the testament to what they're capable of to hear them seamlessly running from centipede feet to the huge guy wire hits I got.

Here's that BBC vid (check out the contact mics visually at 2:00 and then the recording at 3:40):





Now onto my vids. First up are the guy wires.  The single most interesting thing that I discovered was that I could resonate one wire by striking the other, probably through some connection that they were making underground.  You'll see in the vid that they're not buried right next to each other though, so it's possible that the contact mics are actually just picking up sympathetic vibrations.  It's all very cool though, and there is TONS of low end, so crank up the speakers.

Again, this audio is 100% unaltered - not even gain changes.




Next up is the metal fence that was nearby.  I did some similar stuff where I was striking the surrounding objects and getting indirect vibrations, which was pretty cool.  The distortion sound in one of the channels isn't clipping, its the effect of the sticky tape losing its grip.


And for fun, here's a 96k downloadable soundcloud vers of the guy wires.  Enjoy!