Looking for best mic/software/eq combo for HT audio metrics

Discussion in 'Home Theater Projects' started by Trenton McNeil, Jun 12, 2003.

  1. Trenton McNeil

    Trenton McNeil Second Unit

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    I would like to set my subwoofer to the appropriate crossover level in balance with my other speakers, as well as graph the response curve of my entire system in my front room, from various listening positions, to help determine how much eq would be needed to correct tones, as well as experimentation with sound damping on walls, etc.

    What I do NOT want to do is go out and buy huge passive xover systems for each output....I do not run separates currently, so if I must go with eq, it will be an expensive proposition...

    That said...what would be best is a good full range mic combined with software with which I can use a laptop to graph response curves, as well as the best test tone software or cd/dvd's for these tests.

    This seems best suited to the expertise of the DIY group, forgive me if I have posted in the wrong forum.

    Thanks in advance!

    -tm
     
  2. Rob Formica

    Rob Formica Stunt Coordinator

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    You have several software on the market that can do what you're looking for. The two most popular here are:

    http://www.etfacoustic.com/
    http://www.trueaudio.com/

    as they are intended for consumer use... but there is also:

    http://www.purebits.com/
    http://www.spectraplus.com/
    http://www.libinst.com/products.htm
    http://www.soundtechnology.com/home.htm

    which I know very little about. Another software that might interest you is CARA which is more or a theoretical prediction software. It calculates the optimum theoretical seating and speaker positions... there was a review of this at Secrets of Home Theatre and HiFi some time ago, and it is available from:

    http://www.rhintek.com./

    As for test tones, I generated my own using the free software NCH and then burnt them onto a CD.

    http://www.nch.com.au/tonegen/

    You could also buy a test CD from Stryke...

    Hope it's of some help...
    Rob
     
  3. Trenton McNeil

    Trenton McNeil Second Unit

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    How about Microphones? Any recommendation there? I doubt a normal full range Radio Shack mic will fit the bill?
     
  4. Rick Guynn

    Rick Guynn Second Unit

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    Alot of peolpe use the Behringer ECM8000 measurement mic. It is supposed to be flat from 22k to around 10Hz and is extremely cheap for a decent microphone. I have one and use it for a number of different purposes, including measurement.

    RG
     
  5. David_Rivshin

    David_Rivshin Second Unit

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    I second the suggestion of the Behinger ECM8000. To power it (requires phantom power) I bought a UB802, although an MX602 will work just as well for $10 less. Total cost was $135 from zZounds for the ECM8000, UB802, mic cable, and some ear plugs (I don't want to go deaf while improving my accoustics [​IMG] ). I also picked up a mic stand with boom from partsexpress (242-045) for $25 so I can position the mic right at ear position.
    All in all total cost was around $200 (including more cables to/from my theater), and I wrote my own software for the measurements I wanted to take. Not cheap (or fast), but this is a hobby after all [​IMG]

    Also check out www.linearx.com, they have software and calibrated microphones. It looks like they actually test each mic and send correction values with it so you can get very accurate measurements. If you're doing very serious measurements, such as for designing crossovers or speakers in general, it might be a better way to go for alittle more money.

    -- Dave
     
  6. or if you feel ambitions, you can DIY....
    build the Wallin Pre-amp II and two together your own mic with the Panasonic WM-61A capsule from digikey.
     
  7. VinhT

    VinhT Second Unit

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    Just wanted to make a comment about using a laptop. I have TrueRTA and would love to use it with my laptop, but cannot. Laptop sound solutions are not as clean as their desktop counterparts. I found my laptop's sound input/output to be very noisy. The response fluctuates a great deal, so TrueRTA is unable to compensate. As a result, when I EQed my vehicle I had to bring my regular computer out to the garage. Something to keep in mind.

    -Vinh
     
  8. BruceD

    BruceD Screenwriter

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    Two items are important with a laptop, and it's every bit as clean as my desktop PC:

    1) Use the LINE-IN and not the MIC-IN for data input

    2) If you use ETF5 acoustic software, and have a full-duplex sound card in your laptop (I do), the software will auto-compensate. This works great and with very high quality.
     
  9. Richard_M

    Richard_M Second Unit

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    Hello Bruce

    I don't have a laptop yet, but was thinking of getting a Soundblaster Extigy external usb sound device to use not only on my main machines but also with a laptop. (I don't nead it for my main machine but if I got it I may as well play with it)

    Info on the device is HERE

    The reason for looking at this was that I have heard that a lot of notebooks don't have full duplex cards, where as this device does support full duplex.

    I want to use it with ETF5 so I can help setup my friends home theatre's, and also when we eventually move house my computers won't be near the home theatre room.

    Has anyone used one of these devices and if so how did they go?

    Hello Trenton,

    I have used both TrueRTA,& Etf5, where Truerta looks great in showing the realtime response I found Etf5 much easier for me anyway to set up my 3X subwoofers in seperate locations using a behringer FBD.

    You can download demo's of some of the programs that Rob listed, and if you find one you like the look of have a search through this forum for feedback on it. This is what I did, the help that is available here is amazing.

    Good Luck,

    Richard
     
  10. Stephen Dodds

    Stephen Dodds Second Unit

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    A couple of other external soundcard options are the Audiotrak Maya 5.1 and the new cheaper Soundblaster MP3+.

    Steve
     
  11. BruceD

    BruceD Screenwriter

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    Richard,

    No I haven't tried a usb external soundcard. So, I can't offer much help to you on that.

    At this point if a notebook isn't more than a few years old and has a DVD player option, I would think it comes with a full-duplex soundcard, but I haven't looked lately so I don't really know.
     
  12. Jake K

    Jake K Stunt Coordinator

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    I have a Sound Blaster Extigy on my desktop machine and it's great, much better sounding than the SB Live card I had. Just make sure your computer is fast enough, it works great on my 1.5Ghz machine, but not on my 500Mhz Compaq desktop. The sound skips on a slow computer.
    And it comes with that nifty remote too!
     
  13. Joel X

    Joel X Stunt Coordinator

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  14. MingL

    MingL Stunt Coordinator

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    Am now using the new Creative sound Blaster MP3+ (aka Digital Music in Asia)

    Its basically a watered-down version of the Extigy. It costs me $95 singapore dollars, so it should be approx US$60 for my American friends.

    Its got in and outs for line-level, optical and headphone/mic level. It works fantastic for my ol' Pentium 2 333MHz notebook. IMO its a much better deal for us HT ppl who don't need the features on the Extigy, but still want the line-level in/outs. Its pretty small palm-sized gadget thats USB powered, so no need for any power dongles.

    Best of all, it works in Spectraplus.

    I hope it works fine with the Beringer ECM8000 meas mic.
     
  15. Joel X

    Joel X Stunt Coordinator

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    For the ECM8000 you will need phantom-power since it is a condenser mic, a Behringer Eurorack MX02a is what I have. This is about the cheapest way I could find to get reasonable phantom-power.
     
  16. MingL

    MingL Stunt Coordinator

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    I've got a Rolls phantom power to power up the mic. From the Rolls phantom mic-out, I intend to bring it to the line-in of the SoundBlaster Line-in.

    Am I doing things correctly? Or should I have a pre-amp stage in between the Rolls Mic-out and SB Line-in?
     
  17. Stephen Dodds

    Stephen Dodds Second Unit

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    I now have the same SB MP3+ USB card. You just go mic, to phantom power, to line in.

    There is a considerable difference in measurements between using the USB card, and the mic ins on my laptop. Unfortunately due to Toshiba's incredibly poorly constructed laptops, I can't compare the line ins on the laptop to the USB ones.

    Steve
     
  18. RichardHOS

    RichardHOS Second Unit

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    I finally ordered an ECM8000 today. I've been meaning to do it for a while, but never got around to it. I won't really need it until the house/theater construction is complete at the end of the year, but it would be nice to go ahead and get the software and mic and start the learning process so that setup/calibration is less of a headache when the time comes.

    I have a nice dbx 386 preamp/ADC already, and a nice M-audio Delta DiO soundcard, so I should be set on the hardware front now.
     
  19. MingL

    MingL Stunt Coordinator

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    Stephen,

    Do you feel its necessary to have a mic preamp between the phantom power and the line-in? How is the signal level? Useable at all? Or better to have a mic preamp?

    I'm really crossing my fingers that I do not have to buy a mic pre-amp just to get the ECM8000 to work with my notebook.
     
  20. Stephen Dodds

    Stephen Dodds Second Unit

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    I don't use a preamp and the level is OK.

    Steve
     

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