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Thread: Looking for Room Measurement and EQ Recommendations

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    Webmaster Don McRitchie's Avatar
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    Looking for Room Measurement and EQ Recommendations

    As can be seen in my recent Model 19 post, I have discovered that EQ is indispensable with this system. However, I dont think I am making the most effective use of EQ with my 25 year old parametric equalizer and only my ears to guide me. I would like to try something more effective, like an RTA and more comprehensive equalization.

    After doing a bit of research, Im leaning towards a PC solution. I was thinking of adding a pro USB sound card to my laptop, getting a calibration mic and mic preamp, and then purchasing RTA and EQ software. I like the idea of being able to sit at my normal listening position, with the PC on my lap making fine adjustments to system EQ. Does anyone have any recommendations on USB soundcards, mics, and software that could help me reach my objectives?
    Regards

    Don McRitchie

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    Senior Member Ian Mackenzie's Avatar
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    Don,

    Bo is an equ buff, zip him a pm.

    Ian

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    Super Moderator Hofmannhp's Avatar
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    Re: Looking for Room Measurement and EQ Recommendations

    Originally posted by Don McRitchie
    .......... Does anyone have any recommendations on USB soundcards, mics, and software that could help me reach my objectives?
    Hi Don,

    last week I got my new mic for measurements.......a Beyer dynamics MM1. This is a relatively cheep condensor mic which needs phantom power between 12 and 48VDC. In Germany its available for 159,-Euro (about 194,US$) plus tax. It has a frequency response like a line from 20Hz to 20kHz.

    Soundcard: M-Audio Delta 1010 Lt
    Software: ???? (I need also a good idea)

    HP

    PS: the CDRom I sent you in January does not reach you???
    Please help us save more info about the vintage systems. Let us register your speakers and drivers.

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    Senior Moment Member Oldmics's Avatar
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    Hi Don
    I can make some suggestions that will address half of your question,unfortunatly not the whole answer.Since you are asking about doing two different chores,I would like to address the analysis software portion of your query.

    There is a fair amount of software analysis product availiable.Much is availiable as freeware.Depending upon what your data gathering requirements are will determine the amount of money you will be parting with.Simple one third octave measurement programs are availiable thru a variety of sources

    such as a demo of SmarrtLive
    ,
    http://www.siasoft.com/products/demos.shtml

    Praxis also has a freebie

    http://www.libinst.com/PraxisNews.htm

    My favorite is the Praxis.If you decide to purchase the Praxis go with the recommended microphone. The calibration information is easier to obtain and is required to input to the software program.The key piece of information to impart here is to make sure that the mic and software are voltage and frequency aligned thru the software information so that accurate measurements are obtained.Not calibrating the mic to the software is a no-no.
    That really is the only trick,the rest is the learning curve on any of these devices.

    It takes years of working with these devices to become a craftsman skilled enough to understand what is going on in the programs.I am still a novice but reley on the information they produce.All of these programs do so much more than RTA.Spend some time getting to know what they can offer.



    Onto the E.Q. portion of your question,that is a chore for someone else as my knowledge only extends into stand alone hardware devices that are manipulated in the digital realm as opposed to a PC software program. I am aware of some studio mastering software that exists but I am not knowledgeable enough to make a recomendation.
    Happy tweeking!
    Oldmics

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    Senior Member JuniorJBL's Avatar
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    Digital?

    Originally posted by boputnam


    Digital gear, from my experience, only begins to work when it is horribly expensive, and even then is simply not matching the sound of analogue gear at much lower price-points.

    Would you say somthing like the dbx driverack 260 is not good?
    I was thinking of using this piece for doing all electronic crossovers in my system. Your opinion is very welcome.
    Shane

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    Administrator Robh3606's Avatar
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    Hello Don

    Why PC driven?? You will need the laptop to do the EQ for you?? I understand that you can tweek from the "sweet spot" but what are you going for?? I would assume flat in room with some roll off up high and some potential boost in the last octave depending on taste. I use the Berhringer 8024 in RTA mode and use my Urie 839's for EQ. I just drop the mikestand on the "X" sit in front of the RTA and adjust the EQ's to get the curve. I use pink noise exclusively to set the curve, have a listen, then reshape if required. I won't tweek it to a single recording as I really don't know what that baseline is. I do know what the pink noise baseline is. Flat is where it's at. Once I find the "curve" it's set and forget. It's tedious and the subtle EQ changes and driver level changes makes all the difference. That's why I gave up on the by ear route too. The final say is by ear but like you said you really need the tools. End result is worth all the work. The stuff that's really good is spectacular with everything else being what it is. If you plan on tweeking real time on music you had better get something with multiple memories of you are going to drive yourself nuts. That much flexabillity cut's both ways.

    If you plan on Vinyl or SACD, DVDA in the future do you want to run this through a digital set-up?? Are the analog options that poor??


    Rob
    Last edited by Robh3606; 03-30-2004 at 10:07 AM.

  7. #7
    Senior Member JuniorJBL's Avatar
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    Crossover

    I am more interested in the crossover then anything else. You can choose different slopes and types of crossovers instead of being stuck with 24db (or whatever) per on your UHF/HF. I myself prefer no eq if I can get away with it. But that said, I do the same as rob and use pink noise to set a room eq and leave it alone. Yes if it is live then I will do as you do. I have used this piece for live and it seems to work well, but home is a much different enviroment as we all know. I could step up to the 400 series which are VERY expensive($3000) but maybe the DAC's are better?

    Or do we go back to using passive's to do what we want with our speakers?
    Shane

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    Webmaster Don McRitchie's Avatar
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    Thanks to everyone for the advice. The following is my attempt to answer some of the questions raised.

    First off, I don't perceive digital to be greatly inferior to analogue. The cards I am interested in operate at very high digital resolutions and, quite frankly, I dont think the D/A converters are that bad. At least not in comparison to the compromises I would have to accept in the analog domain. From what I understand of analogue equalizers is that they can create ringing and phase errors that are far grosser than any digital artifacts. Further, the flexibility offered by digital equalization in software is unmatched by any analogue device that I am aware of.

    The reason to go PC based is for cost effectiveness and longevity. I can buy a sound card and software for less than the price of hardware RTAs and equalizers. Plus, I am in the position where I can devote a PC to this application since I have two kicking around the house. Upgrades are easily accommodated with changes to software or sound cards as needed. Changes to a standalone EQ can only be accommodated by replacing the entire unit.

    Regardless, there seems to be consensus that PC is the way to go for measurement. To that end, I am still open for any suggestions for an external sound card. It has to be either USB or Firewire compatible since it is intended to work with a laptop.
    Regards

    Don McRitchie

  9. #9
    Administrator Mr. Widget's Avatar
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    Originally posted by Don McRitchie


    First off, I don't perceive digital to be greatly inferior to analogue. The cards I am interested in operate at very high digital resolutions and, quite frankly, I dont think the D/A converters are that bad. At least not in comparison to the compromises I would have to accept in the analog domain. From what I understand of analogue equalizers is that they can create ringing and phase errors that are far grosser than any digital artifacts. Further, the flexibility offered by digital equalization in software is unmatched by any analogue device that I am aware of.

    Don,

    With all due respect, in the theoretical world I agree with your logic, however in the real world the damage done by analog circuits is less disconcerting to the ear than that done by digital. That said, if you are going to use super high end A/D-D/As and keep the digital resolution at or above 24 bit 96KHz, you might have an argument.

    Besides soon you will have a pair of Project May speakers that one would hope won't require fixing.

    Widget

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    DEQX - the solution.

    The DEQX PDC 2.6 is pretty much exactly what you are looking for, Don. It uses a PC and calibrated mic for measurement, but has a stand-alone unit with 10 bands of parametric EQ per channel, a 3-way digital crossover, independent driver and room correction, and complete phase coherence (plus more features as well). See: www.deqx.com I recently got one of these for my own 4 or 5-way active horn speaker project. I have yet to dig into it in depth but what I heard @ CES was convincing enough for me to throw down the $. It can take analog (A/D @ 24/96+) or digital in and offers single-ended, balanced and/or digital outs. It also has a preamp option to allow use as a preamp as well. It's not a cheap unit, but sounds better than any analog or digital piece I have heard yet, not to mention the feature set eclipses anything I have yet seen.

    Regardless of how project May turns out, this is the sort of unit which could bring benefits to any system. Even with the best (passive) optimizing of the project May speaker, it could still be improved by a unit like this, in fact I'd go so far as to say any speaker/room combination could likely see reasonable gains in performance from a well-integrated system such as deqx. JBL themseleves notes that EQ (done *right*) is pretty much required for best performance out of any system. I forget the white paper that covered this but I found it here on lansingheritage.org.

    If you have more questions, feel free to email direct about it.

    thanks
    -Ed

  11. #11
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    If you want to play around with a digital crossover and EQ system, that you can resell later on, I would try out the Behringer DEQ2496. I have seen them for as low as $350. If you decide digital is for you, then you can sell it on ebay and invest in a more expensive DBX or Ashley unit.

    As far as firewire soundcards, I would look at the M-Audio Firewire 410. It would allow you to run stereo 4 way speakers. It may be easier and less expensive to just design better crossovers for the Altecs and add some strategic room treatments.

  12. #12
    RIP 2010 scott fitlin's Avatar
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    Re: Digital?

    Originally posted by JuniorJBL
    Would you say somthing like the dbx driverack 260 is not good?
    I was thinking of using this piece for doing all electronic crossovers in my system. Your opinion is very welcome.
    Shane
    Ill definitely say the DBX Driverack 260 is less than what my ears will tolerate! First off, Im an analog man, its what still sounds best!

    Second, as for digital processors and EQ,s the best out there, at this time, would be the BSS 366, or XTA DSP system contollers. Both brands are particularly expensive. Many of the engineers I know who are doing digital, seems to prefer the XTA. But, its expensive!

    But really high quality analog still sounds better. Warmer, more natural, richer, fuller sound, especially in the bass.

    As for EQing, if your using a good pair of analog EQ,s such as White 4200,s or 4400,s; an RTA is a good tool to have. Pink noise the room, read it with the RTA and mic, and after youve gotten your basic curve, you can fine tune by ear. Audio Contol makes a nice 1/3 octave RTA with pink noise generator, and comes with calibrated mic! See, if you can rent one from a pro sound shop for the weekend. If you can, this is the way to go.




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    measuring and interpreting the speakers results right is not easy and there are many faults you cant cure with EQ or delay.
    Simply using a measurement mic, run a frequency or phase test and compensate the frequency response with the EQs is not the way to make a good sounding room, but the analysis is a first impression of what is definitely wrong with the speakers and the room. (in most cases the room is the cause for bad sound).

    The guys I know who use their digital drive racks in their listening positions are always trying out different setups for a better sound and the EQ positions may vary for different kinds of music. When you have the right position of the EQs and delays, you can burn your CDs using the compensations and then remove the whole digital correction stuff. After trying a few digital X/Os my only recommendation is: look what the pros use and buy a tool and not a toy.

    BTW, I always wondered how the hifi-guys can judge a sound of a speaker or component with a record they never heard live or in front of the mixing console. A simple way to judge a speaker right is by doing simple recordings yourself with a voice you know well and then playing the sound through the speakers. You can judge in a few moments what is right and what is wrong with the speakers or the room.

    Regards,

    Rafael

  14. #14
    Senior Member Steve Schell's Avatar
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    Spectra Plus

    Hi Don, group,

    Several years ago I purchased the spectrum analysis program called Spectra Plus. I paid about $600 with all the options. I can't comment on its virtues compared to the competition, as I haven't tried the others. SP works very well, though. A friend and I taught a class for fellow piano technicians where we voiced a piano, and illustrated the changes to the tone visually using the spectrum display and a data projector with a large screen- the class was a hit!

    I haven't had SP installed for the past couple of years, since I purchased an LMS system. I need to get it going again though, as it does some things that LMS can't do, like the FFT spectrum display.

    A 30 day free trial version of SP can be downloaded at:

    http://www.telebyte.com/pioneer/

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    Moderator / Treasurer/Marketplace Czar boputnam's Avatar
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    Lake Contour

    Hey, Don...

    My engineer phoned from a large install they're doing in Albuquerque using Lake Contour controllers linked to SmaartLIVE. Cat's meow...??

    I've not used this, and judging from the budget on this build it looks wonderfully expensive!!

    http://www.lake.com.au/contour/SmaartLiveController.htm

    Anybody out there used Lake Contour gear? oldmics?? subwoof??
    bo

    "Indeed, not!!"

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