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Thread: Testing room/speaker acoustics

  1. #21
    oferab Guest

    Default Re: Testing room/speaker acoustics

    I use Audio Precision MLS measurement to measure the frequency response of the speaker, you can eliminate the reflection problem using this system, and if you have a anechoic room, you can also measure low frequencies

  2. #22
    Join Date
    Jan 2006
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    South of England, UK
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    Default Re: Testing room/speaker acoustics

    That's an extremely expensive system! I think you'll find that LOG CHIRP (a sort of swept sine) is more useful in reflective environments than windowed MLS. You do not need an anechoic room to measure the low frequencies: you can use a stitched near-field measurement if you are very careful.

    MLS doesn't really put enough energy into the low frequencies to get a truly reliable/believable result in my experience but the AP kit is very fine indeed for amplifier measurement.
    Alan A. Shaw
    Designer, owner
    Harbeth Audio UK

  3. #23
    Join Date
    Sep 2007
    Location
    United Kingdom
    Posts
    34

    Default Re: Brass instruments - very difficult to reproduce ....

    Quote Originally Posted by Alan Shaw
    You can not chemically remove the taste of peat from whisky; it is bound up into the fabric of the final experience.
    Very true but sadly they are still finding ways to add the peaty taste that so many of us love with additives.
    If they can find a way to ruin perfection for sound commercial reasons they will.

    Just as an aside what is your favoured malt ? Mine is Aardbeg the original 10 year old but I know it is a little too idiosyncratic for some.

  4. #24
    Join Date
    Sep 2009
    Location
    Malaysia
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    508

    Default REW Room Analyzer - help needed

    Hi everyone and especially to Alan,

    This is my first attempt using REW and not sure if I have done it correctly. I used a SPL meter and also a small condenser mic used to setup my Onyko AV but found the waterfall plot didn't reflect what I hear in the room. The bass in my listening room is sufficient but the waterfall plot shows it is lacking. I suspect I didn't calibrate the sound card correctly or there could be software error in not compensating for the C or A weighting. There is slight error in the reading around 50Hz which is due to the air cond hum like noise.

    Any help is greatly appreciated. I tried at REW forum but so far no response.

    Thanks in advance.
    ST





  5. #25
    Join Date
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    Default

    OK I'm just passing by.

    First, and I'm not criticising you please understand, what do you think those pretty charts are actually saying to you, the reader? Before we can even begin to interpret them as science we have to understand why they are not just attractive pictures.

    What are they attempting to convey? Or specifically, why have you been persuaded to invest your valuable time and money in this measurement system as opposed to any other? What convinced you of its merits? Why not just trust your ears as you have before? I really like the colours of the top chart - would make a great wall-picture!

    P.S. Don't forget what we said here about reporting and influencing!
    Alan A. Shaw
    Designer, owner
    Harbeth Audio UK

  6. #26
    Join Date
    Sep 2009
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    Default Retitled: REW Analyzer - Criticism and Sarcasm needed

    Quote Originally Posted by A.S. View Post
    ....First, and I'm not criticising you please understand...
    ...... I really like the colours of the top chart - would make a great wall-picture!
    There goes whatever hope of getting any help about those pretty pictures.

    ST

  7. #27
    Join Date
    Jan 2006
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    Default

    Would you mind giving me a decent answer to my entirely reasonable question if you don't mind? I really don't have the time to waste on sarcasm.

    I am not here to sell or advise on third party room correction systems and whatever input I care to make deserves a proper answer. If you are unable to advise us here on how you interpret those graphs, as you have experienced from the manufacturers themselves, you can't expect me to do all the thinking.

    But I do like those colours very much. They remind me of a pull-up poster we designed and still sometimes use at exhibitions.
    Attached Images Attached Images
    Alan A. Shaw
    Designer, owner
    Harbeth Audio UK

  8. #28
    Join Date
    Jan 2010
    Location
    Canada
    Posts
    30

    Default Interpretation of plots

    Hi ST,

    Probably better suited you ask in the REW forum (google it). Two things I can think of off the top of my head:is your mic calibrated to account for bias it may be introducing? Same applies to the sound card. Next you should minimize ambient noise such as you a/c unit as it introduces further bias.

    To Alan's question what this plot will identify (in theory) are room modes whereby certain frequencies will appear as peaks and nulls depending on how your speaker interacts with the room. In my case I have a 80hz peak in my room (resonant freq.) and I could probably benefit by adding some additional absorption or by repositioning my speakers. Either way you don't need to rely on a plot to tell you if something doesn't sound right, try experimenting with the above suggestions and see if that helps.

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