damonrpayne Posted January 1, 2008 Share Posted January 1, 2008 http://www.engadgethd.com/2007/12/31/xtzs-room-analyzer-for-your-audio-tweak/ Quote Link to comment Share on other sites More sharing options...
DrWho Posted January 1, 2008 Share Posted January 1, 2008 An RTA is not the proper tool for measuring room acoustics... Quote Link to comment Share on other sites More sharing options...
mas Posted January 1, 2008 Share Posted January 1, 2008 An RTA is not the proper tool for measuring room acoustics... How about if it is combined with an EQ? [] Edit: Do I have to mention that this is perhaps the most over the top absurd tongue-in-cheek suggestion I can make with the biggest grin and rolling of the eyes??? [][][] Quote Link to comment Share on other sites More sharing options...
Groomlakearea51 Posted January 1, 2008 Share Posted January 1, 2008 But then again, here's another offering from the same website.... Quote Link to comment Share on other sites More sharing options...
Chris A Posted January 1, 2008 Share Posted January 1, 2008 Probably couldn't hurt, yea? Unless of course one forgets to use ears, too. If you've got the money, we've got the time to read your review(s). That'd be a good subject for a not-for-profit web site, wouldn't it? Regards, Chris Quote Link to comment Share on other sites More sharing options...
Chris A Posted January 1, 2008 Share Posted January 1, 2008 An RTA is not the proper tool for measuring room acoustics... What is your suggestion for room acoustics measurements? Chris A. Quote Link to comment Share on other sites More sharing options...
DrWho Posted January 1, 2008 Share Posted January 1, 2008 TEF, MLS, Chirps...anything that can provide the impulse response of the system. Quote Link to comment Share on other sites More sharing options...
mas Posted January 1, 2008 Share Posted January 1, 2008 The 'problem' with an RTA is that a frequency domain response shows a summed view of what 'has' happened, while it lacks the ability to provide necessary information allowing for a detailed anlysis of the factors that provide insight sufficient to understand 'how' and/or 'why' that various individual signals interacted via superposition to create the summed view afforded by the RTA. In other words, with the RTA, you lack sufficient insight into the individual factors that contribute to create the frequency response. You know 'what happened' from one perspective, but you have no idea as to how. And to make acoustical adjustments you need the details telling you 'how' things happened, as you only have control over the individual factors. (Typically, an EQ installed at this point in the process fails to resolve the issues for the same reason, it is attempting to resolve the gross errors that result from superposition without acting atomistically, and independently, upon individual component signals whose interaction results in the summed response.). To use a poor metaphor, the RTA provides a snapshot of a multi-car pileup after it has happened. But if fails to provide a more atomistic view of how and why the accident came to occur. You need a method that will allow a greater resolution of each individual component variables, thus allowing insight into what sources, real or virtual, contributed via superposition.to create the result. The time domain perspective allows this and much more, as this perspective also contains information sufficient to also convolve the frequency domain as well as phase relationships of each component signal. As Doc mentioned, the primary tools for this are TDS (time delay spectrometry) and MLS (maximum length sequence). The primary advantage of TDS is the presence of definable agile tracking filters that actively window the sweep providing not only significat noise immunity, but also the ability to isolate individual reflections to a greater degree than does the simple windowing ability of MLS. The fundamental respose that contains all of the convolvable system information for all domains is the impulse reponse. From this, the frequency response as displayed by the RTA is but one very small component view. Attached is a domain diagram showing the fundamental relatiosnhips of the various available perspectives. Quote Link to comment Share on other sites More sharing options...
Chris A Posted January 2, 2008 Share Posted January 2, 2008 The definition of "RTA" (real-time analyzer) now used is narrower than prior experience--which also includes time domain impulse, chirp, or pseudo-random cross correlation techniques. Analyzers not having these capabilities are of limited value for understanding acoustics in almost any venue. All acoustic installations have either reflection, standing wave "modes" (including feedback) issues, or need analyzer capability for setting driver array delays. Thanks for your responses. Regards, Chris Quote Link to comment Share on other sites More sharing options...
DrWho Posted January 2, 2008 Share Posted January 2, 2008 narrower than prior experience--which also includes time domain impulse, chirp, or pseudo-random cross correlation techniques Are you saying you've used RTA's that use those techniques? If so, I would be interested in some specific models. [] Quote Link to comment Share on other sites More sharing options...
Chris A Posted January 2, 2008 Share Posted January 2, 2008 narrower than prior experience--which also includes time domain impulse, chirp, or pseudo-random cross correlation techniques Are you saying you've used RTA's that use those techniques? If so, I would be interested in some specific models. Unfortunately, it was 25 years ago in the geophysical industry doing seismic source/receiver array design and development (both impulsive and "chirp" systems). I'm sure those specialized systems are no longer used or available. I assume that laptop applications with calibrated mikes are the order of the day in audio. Chris Quote Link to comment Share on other sites More sharing options...
mas Posted January 2, 2008 Share Posted January 2, 2008 There have been several technologies that have used signals reflected in the time domain to determine densities, distances, and other related properties in substances, be it water, earth, or such such materials as wire (such as time domain reflectrometry - TDR - commonly used to detect cable length and anomalies in the cable based upon variances in impedance based upon the reflections inherent in an unterminated load). In fact ,the TEF (and the specific technique called TDS) resulted directly from Heyser's research in underwater detection and measurement at the Jet Propulsion Lab in ~1967. But it was not a commercial product until Crown brought it to market as the TEF-10 in the early '80s. Before that applications were limited to such as what Russ berger did in assembling the $30,000 worth of HP & GenRad gear necessary to perform the tests. Prior to the TEF, there was no tool for practically applying techniques that provided the wide multifunctional range of capabilities that some now take almost for granted. That is not to say that D!ck invented physics, or FFT's or any of more basic concepts of which some are sure to want to debate - and which still do not perform the measurements that D!ck defined. But there was no practical device that allowed for the casual measurement of such extensive acoustical properties. Heyser's insight brought the realm of acoustics (to quote Don Davis) "from the 15th century... into the age of quantum mechanics". Subsequently practical tools utilizing MLS and other techniques also allow for varying degrees of measurement and display of many of the acoustical characterisitics now considered most useful. But none of then are considered fundamentally resident in the frequency domain as is the RTA. Quote Link to comment Share on other sites More sharing options...
bodcaw boy Posted January 2, 2008 Share Posted January 2, 2008 narrower than prior experience--which also includes time domain impulse, chirp, or pseudo-random cross correlation techniques Are you saying you've used RTA's that use those techniques? If so, I would be interested in some specific models. doc, tef has a module for an rta. we bought it..... in Christ, because of Gods' grace, roy Quote Link to comment Share on other sites More sharing options...
mas Posted January 2, 2008 Share Posted January 2, 2008 tef has a module for an rta. Sure it does. That is just one of the more limited derivative displays providing for bandpass limited frequency spl. sans phase and other more useful information. But the fundamental limitations as Doc mentioned still remain. Quote Link to comment Share on other sites More sharing options...
NorthernXposure Posted January 2, 2008 Share Posted January 2, 2008 OMG!!! Somene has a graph or chart for everyhting on here!!!! Thank GOD I found y'all. I used "Y'all" That;s pretty good for a Northern boy from Canada Eh?? Quote Link to comment Share on other sites More sharing options...
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