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RTA Mic's

muzicmakenmuzicmaken Posts: 5
edited May 2010 in PA Front Panel
Hello all....
I just got my DriveRack PA yesterday and have been reading everything I can on it.
I've been reading the faq's and searched the posts but could not find the answer to my question regarding the RTA mic.

IS the dbx RTA mic any better than the Behringer 8000 RTA mic?


Thanks for your help.

Ken

Comments

  • DennisDennis Posts: 801
    Thats a good question. I think the plots look similar on the two mics but since the Behringer is \"perceived\" to be the lowest quality mic on the market, I personally would get the DBX.

    Dennis
  • DennisDennis Posts: 801
    Or if you want an inexpensive mic with a simi-cool factor, go here:

    http://www.rationalacoustics.com/store/ ... a-420.html
  • thanks for the (very fast) reply Dennis...The reviews I have read say that that the Behringer is pretty close to Earthworks although it can't handle the max SPL of earthworks or other high end options, but for most people its range is more than enough. And also read that it is almost identical to the Audix TR-40 except for a few cosmetic differences. And also the Behringer is actually made by Tenlux

    I'll check out the SIA but since it is close to the price of the dbx would it be just as good as the dbx or better?

    The frequecy chart is almost identical between the Behringer and the RTA-420..

    Thanks again for your help.

    Ken
  • DennisDennis Posts: 801
    I'm sure all of the cheap mics are similar but the SIA mic is offered by the same people who brought us SMAART and I have seen a number of these mics in use by a few fairly high end consultants. If the mics are roughly the same price, why not buy the cool one...it's all about perception.

    Dennis
  • GadgetGadget Posts: 4,915
    Everything I've read is that the mic tested ok~by those @ the PSW but the low end response was questionable, as well as the higher frequencies... above 3k...the other caveat was that there was not a spec sheet and or that the published frequency plot was a 1 off and not duplicated from unit to unit...Now I realize that only the better mics are going to be lab tested and verified (which if you were going to really try and make critical measurements, should be a prerequisite) but if there was say a 10% reduction in the response above 2k... then that negates the auto EQ in that region, and your top end becomes brighter than the flat response you requested...

    I think, till Dennis pointed to this mic and I don't know enough about it to say if it's better...that the Audix TR40 was the least expensive mic I would consider for use with an FFT type measurement system like SMAART... but with a 28 band sample that becomes a lot less of an issue if you knew what those specific frequencies were doing...

    I'd definately opt for the best mic you can afford...either way...Dennis that mic looks interesting... know anything about it?

    Gadget
  • Looks like I may look into that RTA-420 then...

    I've been trying some new techniques when performing with a new acoustic act I'm in, using a Condenser tube mic on vocals in small club venues. My other group has been using the Driverack PA for a couple years now and we've had great success with it. So I want to try to RTA each venue I go to to get the best sound I can..

    So one of the first pieces I bought for my PA was the Driverack PA this week. I got lots to learn about it....lol...I've been reading like crazy...lol

    Thank you guys for your help.

    Ken
  • GadgetGadget Posts: 4,915
    Ah.. Dennis...you beat me to it...And yes.. I'd have to agree... if it's ok with SIA then I'd say... go for the cool factor!

    As I said muzicmaken... unless you tested a bunch and got a feel for the unit to unit consistency, the spec sheet doesn't mean squat...Look at speaker MFG's, they can make the spec sheet say anything they want...no standards... no real useful info...no testing by independent sources no useful info...
    G
  • DennisDennis Posts: 801
    Somewhere on PSW there is a thread that includes a poster's independent test of several mics including the Behringer. I believe the test was done with SMAART. The Behringer had noticeably the worst high end response above 2 or 3kHz.

    Currently, my test mic kit is two Audix TR40

    Harry Brill, who is a Rational Acoustics instructor (SMAART) as well as a consultant has a bunch of the SIA mics in his kit (or did a year ago). He also has some more expensive mics but since SMAART is capable of 8 simultaneous inputs, a full kit of Earthworks would be a bit \"spendy\" although I am sure that is his goal.

    Dennis
  • DraDra Posts: 3,844
    Gear change.

    I saw on Harmony (I think) and thread about an app for the Iphone that is a FBT analyser. It uses the Iphone's mic. Supposed to be the bomb for people that don't have $1000's to spend on SMAART.

    DRA
  • GadgetGadget Posts: 4,915
    Still a RTA though...NOT and FFT setup...I believe...
  • DraDra Posts: 3,844
    Sorry, meant to say FFT. I followed the link at the time and it \"seemed\" packed with features. I'll try to find the thread link.

    DRA
  • GadgetGadget Posts: 4,915
    An FFT setup requires 2 inputs for comparison...the original signal as it's being sent from the source(console) and the mic input from the speakers.. the console output is then delayed to match the mic input and is compared...I don't see a phone doing that unless it has a second input, and some serious processor power inside, but hey, stranger things have happened...I understand teleportation is a reality... small scale and short distance but none the less...Star Trek here we come! 8)
  • GadgetGadget Posts: 4,915
    http://www.apptism.com/apps/signalscope-pro

    Looks interesting but... still only 1/3 octave, don't see any phase, or time...there are questions about the mic's \"flatness\" frequency response of some models is truncated @ 100hz and 8Khz...and you have to have an Iphone...I don't think so...That's Timmy P.. he used to hang here once in a while...
  • DennisDennis Posts: 801
    From what I can tell, they are using the internal mic for measurement and the headset mic input connector for reference...voila, FFT. Who cares if it's not accurate. It's the coolest toy ever (and I have heard it is fairly accurate). Now we just need an app for EASE. With that and an already existing app for an inclinometer, we are ready to do arenas with our iPhones.

    Dennis
  • GadgetGadget Posts: 4,915
    Really... :shock:
  • DennisDennis Posts: 801
    I don't think it's going to put Rational Acoustics out of business.....

    Dennis
  • Dennis I found this good article that used the RTA-420's and compared them to the Earthworks M30's:

    http://www.prosoundweb.com/site/topic/audio/P15/

    article

    Tuning A System At The Ultra Music Festival With EASERA SysTune


    ken
  • DennisDennis Posts: 801
    Cool article, Ken. What was actually said about the RTA 420 was:

    • The RTA-420 microphone delivered equivalent performance to an Earthworks M30 for subwoofer work. The sensitivity is different but I detected no real difference in either magnitude or phase.

    Where you will see a difference is in the high end response.

    EASERA or SMAART is the next logical step after you have mastered AUTO EQ but want to do more. Keep combing through the various forums....there is a ton of information out there.

    Dennis
  • DraDra Posts: 3,844
    TimmyP uses FFT by Studio Six Digital (iPhone ap)

    DRA
  • DennisDennis Posts: 801
    Invite him over here to discuss iPhoneology. We all seem to have questions about the FFT app.

    Dennis
  • DennisDennis Posts: 801
    Just a little follow up on the RTA-420. I have been following a thread on the forum at the Rational Acoustics website and this bit of information somehow got by me before. The RTA-420 has a diameter of 10mm. The standard calibrator is built to accept 1\" with an adapter for 1/2\" mics. 1/2\" mics seem to be the most common size in this neck of the woods. A lot of people will never worry about calibration of a measurement mic because it really applies only to SPL which is not an issue when tuning a system. Since I brought up the topic of RTA-420's, I felt I should point out their nonstandard 10mm diameter.

    Dennis
  • TimmyPTimmyP Posts: 4
    I got the iPhone and FFT because I am terrible at calling feedback frequencies when ringing monitors out, and FFT tells you what the ringing frequency is in both graph and numeric form (I was supposed to get a lot of briefcase work this summer to pay for it - but I like the phone - it has much better sound than my Treo 650, and other nifty features too - but the extra $30 per month sucks). FFT has also been handy for finding things such as the vocal \"whump\" and hot bass peak that pop up regularly, but not regularly enough to use \"hunt-n-peck\" on a graphic (plus I use parametric when I can). FFT is no substitute for Smaart and the like, but it has a lot more resolution than any other cheapy box or PC program.

    I've not used any of the other audio apps, save for the frequency generator (which I got just to have it).
  • DennisDennis Posts: 801
    Hey TimmyP

    Thanks for stopping by.

    If your main use is for identifying feedback frequencies (and I can relate to that), what does FFT accomplish that a RTA doesn't? And was I correct a few posts earlier in this thread about how to get two signal sources to the FFT app?

    Dennis
  • Hey Guys,

    Sorry to drag up an old thread. I was rooting around on my friend Google and came across this. I just wanted to clear up a few things about the SIA RTA-420 and maybe answer some other questions too.

    The RTA-420 is the same mic as the dbx RTA-M and the Apex 220.
    They are all pin 3 hot (not that it matters)
    They are similar in quality to the ECM8000, as is the Audix TR40 (but they do have that coolness factor).

    I currently carry 6 of them for use with Smaart. They are pretty much flat up to about 5KHz (this goes for every mic I've mentioned in the post so far). Above 5KHz is where they start to wander in response. Would you notice this in a recording? Likely not. Would you notice when EQing your PA, I doubt it. In fact they typically have a rise that peaks around 8-10KHz which might lead you to cut a bit in that range. Certainly not the end of the world. I tend to use my ear when EQing in that area regardless of what mic I'm using.

    Sencore (TerraSonde) offered a matrix switcher with 4 unlabeled mics that are also the same exact mic. The ones I have measured were matched very closely obviously adding a great deal of cost.

    Smaart 6 was not limited to 8 mics, but my preamp was.
    Smaart 7 is not limited to 8 mics either, but my preamp still is.

    Calibration files for individual mics will soon be available IF anyone is interested in making the mic look FLAT to Smaart. The cost is yet to be determined but will likely end up around $50. per mic. A user that NEEDS a flat response mic will likely drop the $600. plus on the Earthworks M30 which is fairly consistent mic to mic up to about 12KHz. If you want flat and consistent mic to mic above 12KHz you jump to the DPA 4007 or perhaps an ACO Pacific. There are others I'm sure.

    There is a Smaart iPhone app that will be available pretty soon offered by Studio 6 Digital. They have teamed up with Rational Acoustics to basically offer the Spectrograph, and Transfer Function.

    One more thing, an FFT can be a single channel RTA or a dual channel Transfer Function.

    Have fun guys. Don't hesitate to email me if you have any questions. Google is your friend there.

    Full disclosure ~ I am a dealer for Rational Acoustics Smaart 7 and I also sell the RTA-420, although my main line of work is as an audio mixer/ system tech.
  • GadgetGadget Posts: 4,915
    Thanks for stopping in Harry! We always enjoy your posts on the PSW. We try to mirror the information there for the folks here. Please feel free to offer advice on any thread.. old or new.

    So your saying the 420 is the SAME mic or that they are similar in that they all (the low budget mics) exhibit the same 5k and up anomalies?
    Thanks
    Gadget
  • I am saying the Apex 220, RTA420, and RTA M are all identical mics presumably from the same Chinese factory. I am also saying all the main stream measurement mics out there exhibit flat frequency response pretty much to 5KHz regardless of price. Above that we start getting into the varying response and consistency vs price.

    I've been using the RTA-420s for over 2 years. I do not feel worried about them being knocked over or smashed. I have dropped my M30 more than once and the cost to repair once is enough to buy 3 of these mics. That being said, it's nice to have at least one more upper end mic to compare to. For the business of signal (time) alignment, and the majority of EQ, these inexpensive mics are a good choice. I feel strongly enough about that, that I'm selling them. There isn't a lot of money to be made with this product, but hopefully the point is made. Even the ECM8000 is good enough for most PA work, particularly if you only use one mic at a time. Considering the price tag, to pay any more is just so you won't get pointed at or made fun of by your friends. Of course you might have other reasons to avoid them.
  • DennisDennis Posts: 801
    In a recent five day Meyer "Comprehensive System Design and Implementation" class, Mauricio Ramirez demonstrated live how little difference there was between various priced mics. Every one in class coughed up their measurement mics and Mauricio projected their respective traces on a large screen (doing the measurements on a Meyer speaker of course). Not the most scientific setting but it got the point across.

    Harry, we met at the Costa Mesa "earthquake" seminar. On the third day when you were setting your rig up in the theater, we discovered we had almost identical vintage 114dB calibrators. You may have moved on but I am still using mine.

    Dennis
  • SWEET! I remember. Yours was BLACK. I still have it, but I am going to probably give it to my good friend Dave Ely. He's out with Earth, Wind, and Fire. I since picked up a CAL200. http://www.larsondavis.com/ModelCAL200.htm It's quite compact and does 94dB as well as 114dB. It does not fit 1" unfortunately. I still have the recording of the earthquake. Fun stuff!
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