Re: smaart 7 how many mics ?
I guess I'll add my info, since I've started using SMAART again. Currently using two Earthworks M30 microphones, a Roland Octa-Capture and a quad core Mac Pro. Only using the two mics right now since that's all we have.
Question for the crowd here, would buying two more M30s be workable? or do they all have to match from the same production time period? In which case it would be better to buy four DBx or Audix measurement mics and use those?
How big is your wallet? Yeah it would be really cool to have a bunch of matched M30's on hand, but what would you gain? Yes your confidence level in your measurements should be extremely high with such a high quality mic. But at some point you need to determine what is "good enough" for what you do for measurements, with the money you invest in test equipment. I've pondered this question myself for quite some time, here's a few considerations:
1. Smaart 7.3 now allows you to use mic compensation curves for each individual mic. This essentially compensates for the differences from one mic to another electronically. While not quite as perfect as buying matched sets of measurement mics from the manufacturer, you can get really close, for less cost.
2. You can buy these compensation curves from Earthworks, specific to each serial number (they measure every mic that leaves their door). Rational Acoustics is providing this service with the test mics they sell, or you can send your mics off to an independent lab to get measured (cross spectrum labs does this). Or you can do a quick and dirty mic compare in Smaart, and get something reasonably close.
3. Most anomalies in decent measurement mics occur at the extreme ends of the frequency response curve, particularly in the HF, but really, how often do you make measurement decisions based on the data shown on the screen in those areas? I propose that if you are going to make any adjustments there, you will be more dependent on listening with your ears than looking at a computer display.
4. Don't forget that when you're doing multiple mic averages, you are in essence "averaging out" those minor differences between individual mics, making any remaining minor differences less of a problem. With properly compensated mics, the net result is a fraction of a dB on an averaged response at a few data points. Certainly not something worth fretting over in the grand scheme of things. It's all about context, so....
5. Given the focus of this board is on live sound reinforcement, and I'm making the assumption that most of us are working in rooms with a capacity of hundreds if not thousands of people, air absorption, background noise, reflections, and other acoustical anomalies are the facts of life we deal with everyday, and pretty much mask those minor differences between mics. If you find yourself measuring recording studios, or performing an acoustical analysis of a performance space often, then spend the money on the best mics you can buy...
6. What are the physical conditions that you are typically setting your mics in? When performing measurements of a system, do you have the luxury of telling everybody to leave, sealing off the room, and doing your work all by yourself? Or are you measuring a system while other crew members are setting up a system, the venue staff are setting up chairs, lifts are going up and down and all over the place getting the rigging done, forklifts zipping around everywhere? Are you measuring under conditions where construction dust is prevalent? I would be terrified of leaving my M30 out of my reach in such an environment, for fear that someone will trip over a cable and knock it over (already happened to me twice). In those cases, I prefer using cheapie test mics with compensation curves. If one of them gets run over by someone, no big deal, go out and buy a new one for under $100. Drop an M30 on the floor, bend the tube, knock the diaphragm out a few microns, and you're looking at several hundred dollars repair bill. Been there, done that, have the t-shirt.
7. Environmental conditions...high heat is the worst enemy for measurement mics with plastic diaphragms. Leave your prized test mics in the back of the truck going through the hot desert (or a very hot summer day), and the tension of the diaphragm may change, altering the frequency response. Yes, the higher end test mics do some "conditioning" of the diaphragm material, but if your entire inventory of mics gets abused, what will you use as a reference to establish whether your test mics are out of calibration? What I'm suggesting is that perhaps you should keep a reference standard level mic back at the air conditioned office, only to be brought out to test your test mics.
8. I'm achieving the best system optimizations I have done yet in my career, thanks to multiple mic averaging, in a fraction of the time that it used to. If I were given the choice of buying one expensive mic, or for the same budget buy a bunch of cheaper measurement mics, I would favour the latter. Personally I have one M30, and a bunch of cheapie test mics. Best of both worlds. My next investment may be a set of mid range test test mics, and/or Lectrosonics wireless.
So my advice:
1. Get a bunch of cheaper test mics with compensation curves. Get something you that suits your confidence level and budget. For some having a bunch of Behringer, Superlux, Apex, DBX, or Rational RTA-420 test mics with compensation curves is "good enough." For others a set of Audix TM-1's, or Earthworks M23's. The new ISEMcom mics from Rational seem to be a good compromise as well. Regardless, make sure you get a compensation curve for each individual test mic. Of course if budget is no issue, then get a bunch of DPA 4007. Leave one of your M30's back at the office, well protected. The other M30 can go on the road with you as a traveling reference standard mic and your within-arm's-reach-companion at mix/test computer position.
2. For the money you save on cheaper test mics, get a Lectrosonics wireless test mic rig. Sure beats lugging around long mic cables.
3. Get some really good mic clips for your test mics. I can't tell you how many of the cheap plastic ones that come with the cheap test mics I have broken. I personally use the WindTech MC-12, but there are other similar ones made by AKG.
4. Get a really good case to protect your mics that's small enough to fit in your carryon bag. I still keep my M30 in it's clear tube, wish they still made those. For my cheapie mics, I use an otterbox cigar case from Rational.
5. Get some windscreens for your mics if you're using them outdoors to cut down wind noise and protect from rain. They also distract airport security from touching the tips of your mics, and protect the tips during transport.
6. Get a cable tester, especially if you're using someone else's cables for your test equipment. I always test unknown cables before setting my system up. Rat sniffer is what I use. It's surprising how many cables I encounter are incorrectly wired!
Hope this helps!
Arthur
