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#1
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Testing The Frequency Response Of A Room
I've seen a few articles on the net about people measuring the frequency
response of their control rooms. How does one go about this? Is it a worthwile exercise, or an exercise in futility? I ask because I want to acoustically treat my control room, and I want to see the results of doing so. One more question: is the http://www.acoustics101.com/ a good source for beginning to learn about the science of acoustic treatment? |
#2
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Testing The Frequency Response Of A Room
On Mar 27, 9:54*pm, "AbsenceStudios" wrote:
I've seen a few articles on the net about people measuring the frequency response of their control rooms. How does one go about this? *Is it a worthwile exercise, or an exercise in futility? I ask because I want to acoustically treat my control room, and I want to see the results of doing so. One more question: is thehttp://www.acoustics101.com/a good source for beginning to learn about the science of acoustic treatment? You get a pink noise generator and run pink noise through your speakers. You use a computer with an audio analysis application like "Smaart Live" and run the output of an analysis microphone like a Berringer 8000 through your computer interface to the application to get a "picture" of your room's frequency response. It's useful in that you can EQ your speakers to match the room to get the flattest response or use room treatment to obtain the flattest response. This EQ would then be your "set and forget" reference for all your mixes. EQ to taste but use a separate EQ to keep the "flat" response you got from the analysis. |
#3
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Testing The Frequency Response Of A Room
AbsenceStudios wrote: I've seen a few articles on the net about people measuring the frequency response of their control rooms. At what listening location ? Truth is, the human ear is VERY good at adapting to room acoustics. As long as the speaker is reasonably 'truthful' there's not that much need to worry since your brain will make most of the required corrections automatically. Exceptions for shockingly live or reverberant rooms obviously. Graham |
#4
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Testing The Frequency Response Of A Room
cedricl wrote: You get a pink noise generator and run pink noise through your speakers. You use a computer with an audio analysis application like "Smaart Live" and run the output of an analysis microphone like a Berringer 8000 through your computer interface to the application to get a "picture" of your room's frequency response. At the measuring mic's location ONLY. Graham |
#5
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Testing The Frequency Response Of A Room
AbsenceStudios wrote:
How does one go about this? Is it a worthwile exercise, or an exercise in futility? Personally, I consider 3 aspects: flutter echo, LF room modes and general deadness. Flutter echo is caused parallel reflective surfaces and should be the first problem addressed. Just clap your hands and listen for non even decay (quick boing-boing like sounds) and identify where it comes from. The quick fix is to hang some Persian rugs on the side walls or put one on the floor if it isn't carpeted. To find LF room modes, place a subwoofer in your listening spot and drive it with a sine wave generator. Pick a start frequency like 28Hz and walk around the room listening for sound buildup or cancelations. Move the frequency up and walk around some more, repeat up to about 130Hz. There are tricks to fixing bass response, but can usually take a great effort beyond simple cylindrical bass traps placed in the buildup spots. I had great results with two helmholtz slat resonators placed in the back wall parallel opposite from the main speakers tuned to exactly the room depth measurement which was a short 5 feet, which gave a half wave @ 110Hz. I got great compliments on how well the NS-10s sounded.. Haha.. It was the room, not the speakers! A dead room is an uncomfortable room. If you follow the LEDE principle placing deadening material in the front half and diffuse/spectoral material in the back and romove any slap/flutter coming from the sides, you'll be in good shape. Futile work? hell no. Either it sounds great or it sucks. |
#6
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Testing The Frequency Response Of A Room
"Soundhaspriority" wrote in message
"AbsenceStudios" wrote in message . .. I've seen a few articles on the net about people measuring the frequency response of their control rooms. How does one go about this? Is it a worthwile exercise, or an exercise in futility? I ask because I want to acoustically treat my control room, and I want to see the results of doing so. One more question: is the http://www.acoustics101.com/ a good source for beginning to learn about the science of acoustic treatment? To do it on the cheap: Get a Radio Shack SPL meter, and a test CD. The Stereophile Test CD2, http://www.stereophile.com/features/338/index14.html , can be found on eBay. Tracks 16,17, and 18 are most useful. The CD employs warble tones. There are also a number of good test CDs and downloads that come out of the car sound and home theatre world. http://www.testaudio.com/testaudio/products.asp http://www.hometheaterhifi.com/down/ http://www.rainfall.com/cdroms/audiotestII.htm www.audioc.com/pdf1/subtestcd.pdf - This is important. Constant tones, provided, for example, by a test oscillator, tend to provoke room resonances, and confuse the user with narrow band modes that are not realistically correctable. Warble tones average the response over 1/3 octave, providing a smoothed version of room response that shows the trend. So far so good. In the bass range, you will be able to see and work on correction of room modes. Most effective means involve acoustics treatments like bass traps. http://www.realtraps.com/ In the mids and treble, you'll see speaker anomalies combined with room absorption. Correction is not straightforward, because the ear perceives the first wavefront differently from reflected sound. Equalizing a room to "flat" is usually very disappointing. http://www.hometheaterhifi.com/volum...es-6-2002.html http://www.modernhometheater.com/how...304/index.html And absorptive material can be overused. The most sophisticated rooms combine both diffusion and absorption. They also include some reflection. The three basics are diffusion, absorbtion, and reflection. We usually have too much reflection, but there is such a thing as too little reflection. According to one concept, the area nearest the speakers should be absorptive, as should all ray traceable first reflections. The remaining area is treated with diffusive, rather than reflective, surfaces. Without reflections, its hard to tell where things are. The Radio Shack instrument does not have a regulated power supply. Not a problem at all. The real problem with the RS SPL meter is that its microphone is very primitive and the electronics are only a little bit better. Better SPL meters can be had for not a lot more money. But, its more to the point to get a flat measurement-type microphone and use it in conjuction with software running on a PC. Besides an inaccurate mike and lack of calibration, measurements are not very repeatable. But if you use it as something to sniff anomalies, it can help you get going in the right direction. Good point. With some difficulty, you can do acoustic measurements that are repeatable within less than a dB. But the hundreth-dB type measurements we can do on electronic equipment are mission impossible if for no reason other than that air currents due to convection in the room will cause measurable changes. A 1 dB error in response over several octaves can have a strong audible effect. Acoustic measurements also tend to vary as you move around in the room, even with warble tones, pink noise, or other test signals. How do you characterize something that changes so much as you move small distances? |
#7
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Testing The Frequency Response Of A Room
On Thu, 27 Mar 2008 21:54:32 -0700, "AbsenceStudios"
wrote: I've seen a few articles on the net about people measuring the frequency response of their control rooms. How does one go about this? Is it a worthwile exercise, or an exercise in futility? I ask because I want to acoustically treat my control room, and I want to see the results of doing so. One more question: is the http://www.acoustics101.com/ a good source for beginning to learn about the science of acoustic treatment? Unfortunately a room doesn't have a frequency response - at least not until you have got it right. There is a different frequency response between any two points in a room - and the differences aren't trivial, they will differ by tens of dBs. To get your room right you need to do two things. First sort out the reverberation time, which you do with absorbent materials. There are plenty of sources which will tell you what reverb time you need at various frequencies, depending on music type, room size etc. Also, you need to prevent modes (the cause of the huge variations). To do this you need to make sure that you don't have flat surfaces facing each other - clutter is your friend. You may find yourself juggling both of these before you are happy. When you have a specific problem at a specific frequency consider a trap. It can succeed where all else fails. With all of this done you will have a room in which frequency response is a meaningful concept. Oh, and it will be essentially flat, because what a good room does is leave the response of the system unchanged. d -- Pearce Consulting http://www.pearce.uk.com |
#8
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Testing The Frequency Response Of A Room
You aren't the least bit interested of the response of the room, but the
response of the speaker within the room. As for using warble tones... They hide the very effects you're looking for. |
#9
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Testing The Frequency Response Of A Room
"William Sommerwerck" wrote in
message You aren't the least bit interested of the response of the room, but the response of the speaker within the room. Agreed. As for using warble tones... They hide the very effects you're looking for. Depends on how wide the warbling is. |
#10
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Testing The Frequency Response Of A Room
On Mar 28, 1:15 am, "Soundhaspriority" wrote:
The Radio Shack instrument does not have a regulated power supply. Besides an inaccurate mike and lack of calibration, measurements are not very repeatable. Bob, you start out so good, and then you throw in a piece of crap like this. A battery is about as good a regulated power supply as you can get, until it dies (which will be obvious since the meter has a Battery Test function). And while it's not perfectly flat, it's pretty darn good, better than most rooms. Someplace around here I have a correction table for it, and it's not more than about 3 dB anywhere in the audible range. The most important thing about acoustic measurements is knowing how to interpret them. That's not simple. |
#11
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Testing The Frequency Response Of A Room
AbsenceStudios wrote:
I've seen a few articles on the net about people measuring the frequency response of their control rooms. There isn't just one. There are millions of them, in every room. Move an inch, and the room response changes. How does one go about this? Is it a worthwile exercise, or an exercise in futility? It's worth doing simple room sweeps to get a sense of where the problems with the room are and what is generally going on. I ask because I want to acoustically treat my control room, and I want to see the results of doing so. How can you acoustically treat your control room if you don't know what the problems are and where they are? One more question: is the http://www.acoustics101.com/ a good source for beginning to learn about the science of acoustic treatment? I have no idea, but I suggest buying the F. Alton Everest book on small studio acoustics (or getting it from the library) and reading it carefully. --scott -- "C'est un Nagra. C'est suisse, et tres, tres precis." |
#12
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Testing The Frequency Response Of A Room
I've seen a few articles on the net about people measuring the frequency
response of their control rooms. How does one go about this? See this: http://www.realtraps.com/art_etf.htm Is it a worthwile exercise, or an exercise in futility? The main reason to measure a mix room is to see how bad it truly is, and to assess the improvement after it's been treated. You do not usually need to measure a room to know how to treat it, because the strategy is the more or less the same for all rooms. I ask because I want to acoustically treat my control room, and I want to see the results of doing so. Yes, that's a good reason. One more question: is the http://www.acoustics101.com/ a good source for beginning to learn about the science of acoustic treatment? I'm biased, but I think this is much better and certainly more coherent written: http://www.ethanwiner.com/acoustics.html Much more he http://www.realtraps.com/articles.htm --Ethan |
#13
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Testing The Frequency Response Of A Room
Scott,
F. Alton Everest has written quite a few books revolving around building studios and using acoustics. I have "Critical Listening For Audio Professionals" and "Master Handbook Of Acoustics." I have started to get into "Critical Listening..." I'm looking for a primer to get me started. Are you talking about his book "Acoustic Techniques for Home and Studio?" Thanks, David ========================= "Scott Dorsey" wrote in message ... AbsenceStudios wrote: I've seen a few articles on the net about people measuring the frequency response of their control rooms. There isn't just one. There are millions of them, in every room. Move an inch, and the room response changes. How does one go about this? Is it a worthwile exercise, or an exercise in futility? It's worth doing simple room sweeps to get a sense of where the problems with the room are and what is generally going on. I ask because I want to acoustically treat my control room, and I want to see the results of doing so. How can you acoustically treat your control room if you don't know what the problems are and where they are? One more question: is the http://www.acoustics101.com/ a good source for beginning to learn about the science of acoustic treatment? I have no idea, but I suggest buying the F. Alton Everest book on small studio acoustics (or getting it from the library) and reading it carefully. --scott -- "C'est un Nagra. C'est suisse, et tres, tres precis." |
#14
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Testing The Frequency Response Of A Room
Ethan,
That is a good amount of material! Thank you for your help, David ========================= "Ethan Winer" ethanw at ethanwiner dot com wrote in message ... I've seen a few articles on the net about people measuring the frequency response of their control rooms. How does one go about this? See this: http://www.realtraps.com/art_etf.htm Is it a worthwile exercise, or an exercise in futility? The main reason to measure a mix room is to see how bad it truly is, and to assess the improvement after it's been treated. You do not usually need to measure a room to know how to treat it, because the strategy is the more or less the same for all rooms. I ask because I want to acoustically treat my control room, and I want to see the results of doing so. Yes, that's a good reason. One more question: is the http://www.acoustics101.com/ a good source for beginning to learn about the science of acoustic treatment? I'm biased, but I think this is much better and certainly more coherent written: http://www.ethanwiner.com/acoustics.html Much more he http://www.realtraps.com/articles.htm --Ethan |
#15
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Testing The Frequency Response Of A Room
Graham,
I have a set of JBL LSR4328's. I am reasonably happy with my listening position, which has been setup to be an equilateral triangle--left monitor, right monitor, and me. What I want is a room that I can count on to be more reliable everywhere I am standing/sitting in it. I forgot to mention that I'd also like to be able to do some tracking in the same room (mostly quiet acoustic instruments). I realize that I could just learn my monitors as they are and get used to mixing with them, but I am looking at this profession as a lifelong career, and with that said, from a business standpoint. I would like clients to be able to hear the results of their playing and my tracking in a suitable environment. I would also like the acoustics to be more uniform, so that in the future, when my studio is no longer in my house, I won't have as hard of a time relearning the monitors I've gathered in a new envrionment. Regards, David ========================= "Eeyore" wrote in message ... AbsenceStudios wrote: I've seen a few articles on the net about people measuring the frequency response of their control rooms. At what listening location ? Truth is, the human ear is VERY good at adapting to room acoustics. As long as the speaker is reasonably 'truthful' there's not that much need to worry since your brain will make most of the required corrections automatically. Exceptions for shockingly live or reverberant rooms obviously. Graham |
#16
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Testing The Frequency Response Of A Room
Arny,
Thank you for the resources. David ========================= "Arny Krueger" wrote in message . .. "Soundhaspriority" wrote in message "AbsenceStudios" wrote in message . .. I've seen a few articles on the net about people measuring the frequency response of their control rooms. How does one go about this? Is it a worthwile exercise, or an exercise in futility? I ask because I want to acoustically treat my control room, and I want to see the results of doing so. One more question: is the http://www.acoustics101.com/ a good source for beginning to learn about the science of acoustic treatment? To do it on the cheap: Get a Radio Shack SPL meter, and a test CD. The Stereophile Test CD2, http://www.stereophile.com/features/338/index14.html , can be found on eBay. Tracks 16,17, and 18 are most useful. The CD employs warble tones. There are also a number of good test CDs and downloads that come out of the car sound and home theatre world. http://www.testaudio.com/testaudio/products.asp http://www.hometheaterhifi.com/down/ http://www.rainfall.com/cdroms/audiotestII.htm www.audioc.com/pdf1/subtestcd.pdf - This is important. Constant tones, provided, for example, by a test oscillator, tend to provoke room resonances, and confuse the user with narrow band modes that are not realistically correctable. Warble tones average the response over 1/3 octave, providing a smoothed version of room response that shows the trend. So far so good. In the bass range, you will be able to see and work on correction of room modes. Most effective means involve acoustics treatments like bass traps. http://www.realtraps.com/ In the mids and treble, you'll see speaker anomalies combined with room absorption. Correction is not straightforward, because the ear perceives the first wavefront differently from reflected sound. Equalizing a room to "flat" is usually very disappointing. http://www.hometheaterhifi.com/volum...es-6-2002.html http://www.modernhometheater.com/how...304/index.html And absorptive material can be overused. The most sophisticated rooms combine both diffusion and absorption. They also include some reflection. The three basics are diffusion, absorbtion, and reflection. We usually have too much reflection, but there is such a thing as too little reflection. According to one concept, the area nearest the speakers should be absorptive, as should all ray traceable first reflections. The remaining area is treated with diffusive, rather than reflective, surfaces. Without reflections, its hard to tell where things are. The Radio Shack instrument does not have a regulated power supply. Not a problem at all. The real problem with the RS SPL meter is that its microphone is very primitive and the electronics are only a little bit better. Better SPL meters can be had for not a lot more money. But, its more to the point to get a flat measurement-type microphone and use it in conjuction with software running on a PC. Besides an inaccurate mike and lack of calibration, measurements are not very repeatable. But if you use it as something to sniff anomalies, it can help you get going in the right direction. Good point. With some difficulty, you can do acoustic measurements that are repeatable within less than a dB. But the hundreth-dB type measurements we can do on electronic equipment are mission impossible if for no reason other than that air currents due to convection in the room will cause measurable changes. A 1 dB error in response over several octaves can have a strong audible effect. Acoustic measurements also tend to vary as you move around in the room, even with warble tones, pink noise, or other test signals. How do you characterize something that changes so much as you move small distances? |
#17
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Testing The Frequency Response Of A Room
Two people have mentioned measurement mics and software.
Are there any decent measurement mics in the $1000 range? Are there software options I should consider beyond SMAART and ETF? |
#18
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Testing The Frequency Response Of A Room
On Mar 27, 10:29*pm, Eeyore
wrote: cedricl wrote: You get a pink noise generator and run pink noise through your speakers. You use a computer with an audio analysis application like "Smaart Live" and run the output of an analysis microphone like a Berringer 8000 through your computer interface to the application to get a "picture" of your room's frequency response. At the measuring mic's location ONLY. Graham Well, you generally only mix from one position so if you set the mic up at your heads' position when you mix it will give a reasonable representation of what you're hearing when you mix. |
#19
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Testing The Frequency Response Of A Room
On Mar 28, 6:12*pm, "AbsenceStudios" wrote:
Two people have mentioned measurement mics and software. Are there any decent measurement mics in the $1000 range? Are there software options I should consider beyond SMAART and ETF? Spectre looks pretty good. A co-worker spent lots of money on a well known big name reference mic and then when guys started getting the Berringer he compared the two using Smaart Live and said, "he wished he'd saved his money". For $80 you can buy two and have some cheap room mics to use for recording when not in use for analysis. A great computer interface is the Sound Devices USB Pre for about $500. I forget what Spectre cost but that combination of application, mics and computer interface should be less than $1000. |
#20
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Testing The Frequency Response Of A Room
AbsenceStudios wrote:
Two people have mentioned measurement mics and software. Are there any decent measurement mics in the $1000 range? Are there software options I should consider beyond SMAART and ETF? There are, but you don't need any more than just a signal generator and your ear. Set the generator for 60 Hz. Stick a finger in one ear. Walk around the room. Find the peaks and nulls. Now try again a third octave up. You'll hear where all the problems are. If you are happy with the sound at the mix position, and you move out of the sweet spot, what happens? Does the high end change, or does the low end change completely? By doing simple tone tests and listening you'll know what changes, you'll know where the room problems are, and you'll be on your way toward dealing with them. If you want a somewhat more sophisticated method, get the Radio Shack analogue sound level meter for $40 or so. A calibrated measurement mike is a great thing, but you don't need one yet. First you need to get a rough idea of what is wrong with the room. --scott -- "C'est un Nagra. C'est suisse, et tres, tres precis." |
#21
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Testing The Frequency Response Of A Room
cedricl wrote:
On Mar 27, 10:29=A0pm, Eeyore wrote: cedricl wrote: You get a pink noise generator and run pink noise through your speakers. You use a computer with an audio analysis application like "Smaart Live" and run the output of an analysis microphone like a Berringer 8000 through your computer interface to the application to get a "picture" of your room's frequency response. At the measuring mic's location ONLY. Graham Well, you generally only mix from one position so if you set the mic up at your heads' position when you mix it will give a reasonable representation of what you're hearing when you mix. Unfortunately, I sometimes move my head around when I mix. I don't keep it clamped in a vise so it's unable to move six inches away. --scott -- "C'est un Nagra. C'est suisse, et tres, tres precis." |
#22
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Testing The Frequency Response Of A Room
On Fri, 28 Mar 2008 18:01:24 -0700, "AbsenceStudios"
wrote: What I want is a room that I can count on to be more reliable everywhere I am standing/sitting in it. Which, as you know, is an impossibly tough requirement, if defined strictly enough. Only a completely dead (or outdoors) environment can be the same everywhere. But a room without terrible resonances can have a similar "character" most everywhere away from the walls. And even this (the lack of terrible resonances) is tough and requires study and effort. The smaller the room, the more the effort required, so bigger is really better, with exceptions outside of most of our price ranges. A fourteen foot ceiling is a gift from your god, but few are chosen. I forgot to mention that I'd also like to be able to do some tracking in the same room (mostly quiet acoustic instruments). You'll hopefully be reading better informed and more diverse ideas, but my personal thought is that the main difference of acoustics between a tracking room and a critical listening room (both are different from "pleasurable" listening rooms, which vary tremenduously with music styles) is adjustable with some serious gobo'ing immediately behind the critical listener's position. A good room in both cases has random (an amazingly difficult goal!) and colorless reflections, and has reflections that begin after an *appropriate* time delay. The time delay can only be addressed geometrically - bigger is better (longer) and numbers under 15 milliSeconds just don't seem get to be "too big". (Although "too big" is certainly possible - it's just that Who can afford it?) The time delay is, of course, the difference between path lengths of the direct and the reflected paths, measured with a tape rule, and divided into 1130 ft/sec in some arcane way. Might involve a reciprocal or something. But simple geometry and an ability to sign large checks. So, IMO, the main difference is in the ability to listen "forward" to critically examine the sound of what's possibly the same room. I realize that I could just learn my monitors as they are and get used to mixing with them, but I am looking at this profession as a lifelong career, and with that said, from a business standpoint. I would like clients to be able to hear the results of their playing and my tracking in a suitable environment. I would also like the acoustics to be more uniform, so that in the future, when my studio is no longer in my house, I won't have as hard of a time relearning the monitors I've gathered in a new envrionment. Seems to me like you've got your **** together. I may not know everything about sound, but I do know about (other folks'!) having their **** together. And it seems like you got it. All the best fortune, Chris Hornbeck Unsigned review of the Rubinstein Beethoven Sonatas on Amazon: "In both CD and SACD mode on several of my players there is a faint hiss from the original tapes captured onto this album. Very disappointing." (some spelling corrected) |
#23
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Testing The Frequency Response Of A Room
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#24
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Testing The Frequency Response Of A Room
"Soundhaspriority" wrote ...
"Mike Rivers" wrote ... "Soundhaspriority" wrote: The Radio Shack instrument does not have a regulated power supply. Besides an inaccurate mike and lack of calibration, measurements are not very repeatable. Bob, you start out so good, and then you throw in a piece of crap like this. A battery is about as good a regulated power supply as you can get, until it dies (which will be obvious since the meter has a Battery Test function).. The RS digital SPL metter has only a "low battery" indicator on the LCD display. So we are at the (undocumented) mercy of whatever the designers decided is "low". In one sense a battery is a rather low-impedance source. But OTOH, its output voltage droops over its useful period. I wouldn't use the word "regulated" to describe that behavior. [snip] Mike, I'm staring at it. Cat no. 33-2055 "Realistic Sound Level Meter" (digital.) The measurement is not repeatable. Repeated use over a short interval results in a series of readings that drift down, just like a flashlight that dims if turned on for a few minutes. Turning it off for a period revese the effect, as the battery depolarizes. With a fresh battery (as recommended in the manual)? Or with whatever happens to be installed at the moment? Are you actually seeing the effect of battery voltage droop, or the effect of the SPL averaging function? It has no battery test function. Lack of a battery test function (not to mention lack of calibration or measured FR) reveals the Radio Shack meter to be a mass-market consumer gadget trying to look like a piece of serious test equipment. I'm not saying that it has no practical use, but not in any objective way. |
#25
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Testing The Frequency Response Of A Room
On Mar 29, 12:20 am, "Soundhaspriority" wrote:
Mike, I'm staring at it. Cat no. 33-2055 "Realistic Sound Level Meter" (digital.) Wrong meter. You should be looking at the analog meter Model: 33-4050 The measurement is not repeatable. Repeated use over a short interval results in a series of readings that drift down, just like a flashlight that dims if turned on for a few minutes. Turning it off for a period revese the effect, as the battery depolarizes. No acoustic measurement is repeatable unless it's in a controlled environment. With the analog meter, you take an eyeball average of the reading. It's too difficult to do that with the digital meter. It has no battery test function. Again, wrong meter. |
#26
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Testing The Frequency Response Of A Room
On Mar 29, 7:31 am, "Richard Crowley" wrote:
The RS digital SPL metter has only a "low battery" indicator on the LCD display. So we are at the (undocumented) mercy of whatever the designers decided is "low". They probably know what they're talking about. In one sense a battery is a rather low-impedance source. But OTOH, its output voltage droops over its useful period. I wouldn't use the word "regulated" to describe that behavior. Alkaline batteries are quite stable after an initial drop in voltage which, assuming a competent design, will be accounted for by voltage regulation in the circuitry that needs regulation. Short term stability of a good battery is very good. Lack of a battery test function (not to mention lack of calibration or measured FR) reveals the Radio Shack meter to be a mass-market consumer gadget Well, what do you expect for $45? Do you think a mass market consumer will make any more useful measurements of his room with a $800 B&K meter? Geez, I have the Alan Parsons Sound Check 2 CD kit which has an SPL meter with 3 dB LED steps built into the case. It's quite informative when looking at sweeps and 1/3-octave noise on the CD. Would I use it to proof and certify a room that I had just been paid big bucks to treat? Nope. But it's fine for telling me where to start working. The Radio Shack SPL meter is just an alternate display. |
#27
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Testing The Frequency Response Of A Room
"Mike Rivers" wrote ...
"Soundhaspriority" wrote: Mike, I'm staring at it. Cat no. 33-2055 "Realistic Sound Level Meter" (digital.) Wrong meter. You should be looking at the analog meter Model: 33-4050 I continue to be pleasantly suprised that RS still sells this model since the "digital" version is also on their shelves. I keep expecting the analog version to disappear without notice as a result of an arbitrary decison by some non-technical "product manager". |
#28
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Testing The Frequency Response Of A Room
"Mike Rivers" wrote in message
... Well, what do you expect for $45? Do you think a mass market consumer will make any more useful measurements of his room with a $800 B&K meter? Geez, I have the Alan Parsons Sound Check 2 CD kit which has an SPL meter with 3 dB LED steps built into the case. It's quite informative when looking at sweeps and 1/3-octave noise on the CD. Would I use it to proof and certify a room that I had just been paid big bucks to treat? Nope. But it's fine for telling me where to start working. The Radio Shack SPL meter is just an alternate display. Some magazine -- I don't remember which -- reviewed all the RS sound-level meters (including at least one discontinued model) within the last year. It seems that the mic has gotten worse and worse with time. It suffers from a rather severe HF rise -- it's anything but flat. If I were designing a "cheap" SPL meter, I'd start by looking for a mic with consistent response (assuming such are available), and then split for another 50 cents in parts to flatten the response. The RS meter is probably useful for relative measurements, but it's likely nowhere nearly as good as it could be for the price. |
#29
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Testing The Frequency Response Of A Room
"Soundhaspriority" wrote in message
"Mike Rivers" wrote in message ... On Mar 28, 1:15 am, "Soundhaspriority" wrote: The Radio Shack instrument does not have a regulated power supply. Besides an inaccurate mike and lack of calibration, measurements are not very repeatable. Bob, you start out so good, and then you throw in a piece of crap like this. A battery is about as good a regulated power supply as you can get, until it dies (which will be obvious since the meter has a Battery Test function).. [snip] Mike, I'm staring at it. Cat no. 33-2055 "Realistic Sound Level Meter" (digital.) The measurement is not repeatable. Repeated use over a short interval results in a series of readings that drift down, just like a flashlight that dims if turned on for a few minutes. Turning it off for a period revese the effect, as the battery depolarizes. It has no battery test function. Conventional wisdom is that the RS SPL meter to buy is the analog one. It has none of those faults, and does have a battery test function. |
#30
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Testing The Frequency Response Of A Room
"William Sommerwerck" wrote in
message "Mike Rivers" wrote in message ... Well, what do you expect for $45? Do you think a mass market consumer will make any more useful measurements of his room with a $800 B&K meter? Geez, I have the Alan Parsons Sound Check 2 CD kit which has an SPL meter with 3 dB LED steps built into the case. It's quite informative when looking at sweeps and 1/3-octave noise on the CD. Would I use it to proof and certify a room that I had just been paid big bucks to treat? Nope. But it's fine for telling me where to start working. The Radio Shack SPL meter is just an alternate display. Some magazine -- I don't remember which -- reviewed all the RS sound-level meters (including at least one discontinued model) within the last year. It seems that the mic has gotten worse and worse with time. It suffers from a rather severe HF rise -- it's anything but flat. If I were designing a "cheap" SPL meter, I'd start by looking for a mic with consistent response (assuming such are available), and then split for another 50 cents in parts to flatten the response. The $2 Panasonic electret omnis need no added parts to flatten them within a dB or less over the whole audio range. People have done mods to the RS meter that changed over to the little Panasonics. There are also low cost SPL meters under $125 that are alleged to perform much better. If you're working in a studio, using your DAW, a Berhinger ECM 8000, a mic cord and some software seems to be the better choice. That rolls back your costs to about the same as the RS SPL meter. |
#31
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Testing The Frequency Response Of A Room
William Sommerwerck wrote:
Some magazine -- I don't remember which -- reviewed all the RS sound-level meters (including at least one discontinued model) within the last year. It seems that the mic has gotten worse and worse with time. It suffers from a rather severe HF rise -- it's anything but flat. Yes, it uses one of the Horn capsules which are Panasonic and Sony clones. They vary a lot from unit to unit. That's still fine if what you want to do is find the peaks and dips. The Horn capsules I have seen as much as 8 dB off from one end of the spectrum to the other... but that's nothing compared with the size of the room aberrations. If I were designing a "cheap" SPL meter, I'd start by looking for a mic with consistent response (assuming such are available), and then split for another 50 cents in parts to flatten the response. The RS meter is probably useful for relative measurements, but it's likely nowhere nearly as good as it could be for the price. True, but the next step up is the Pro-Tek which is three times the price. --scott -- "C'est un Nagra. C'est suisse, et tres, tres precis." |
#32
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Testing The Frequency Response Of A Room
"cedricl" wrote in message ... On Mar 27, 10:29 pm, Eeyore wrote: cedricl wrote: You get a pink noise generator and run pink noise through your speakers. You use a computer with an audio analysis application like "Smaart Live" and run the output of an analysis microphone like a Berringer 8000 through your computer interface to the application to get a "picture" of your room's frequency response. At the measuring mic's location ONLY. Graham Well, you generally only mix from one position so if you set the mic up at your heads' position when you mix it will give a reasonable representation of what you're hearing when you mix. Or in the other direction find the great position in your room and make sure you keep your head there, at least when you do your final check. peace dawg |
#33
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Testing The Frequency Response Of A Room
"William Sommerwerck" wrote in message . .. "Mike Rivers" wrote in message ... Well, what do you expect for $45? Do you think a mass market consumer will make any more useful measurements of his room with a $800 B&K meter? Geez, I have the Alan Parsons Sound Check 2 CD kit which has an SPL meter with 3 dB LED steps built into the case. It's quite informative when looking at sweeps and 1/3-octave noise on the CD. Would I use it to proof and certify a room that I had just been paid big bucks to treat? Nope. But it's fine for telling me where to start working. The Radio Shack SPL meter is just an alternate display. Some magazine -- I don't remember which -- reviewed all the RS sound-level meters (including at least one discontinued model) within the last year. It seems that the mic has gotten worse and worse with time. It suffers from a rather severe HF rise -- it's anything but flat. If I were designing a "cheap" SPL meter, I'd start by looking for a mic with consistent response (assuming such are available), and then split for another 50 cents in parts to flatten the response. The RS meter is probably useful for relative measurements, but it's likely nowhere nearly as good as it could be for the price. Getting a better tool at the beginning is like springing for a 10,999 dollar laser level for doing some general landscaping where a string and a ten cent bubble level will get you measured up closer than you can build / grade you project. In the beginning you will be finding 12 db holes and peaks. Once you get them tamed, if you are not blown away with the improvement, then get the tools that find the tenth dB anomalies. peace |
#34
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Testing The Frequency Response Of A Room
"Scott Dorsey" wrote in message
... The RS meter is probably useful for relative measurements, but it's likely nowhere nearly as good as it could be for the price. True, but the next step up is the Pro-Tek which is three times the price. --scott -- "C'est un Nagra. C'est suisse, et tres, tres precis." ========================= I'm willing to pay three times the price for something that has any chance of giving me any sort of edge on my tracking and mixing. As I said before, I've made a career choice. My goal is to deliver professional results and excellent customer service to clientelle. With that being said, I'm here to learn everything I can from each and every one of you. I read this newsgroup everyday and learn something new everyday. Since I lack a degree in electrical engineering, I will be teaching myself that as well. I think many of you will be suprised at what a tenacious **** I am. |
#36
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Testing The Frequency Response Of A Room
I'm willing to pay three times the price for something that has any chance of giving me any sort of edge on my tracking and mixing. As I said before, I've made a career choice. My goal is to deliver professional results and excellent customer service to clientelle. With that being said, I'm here to learn everything I can from each and every one of you. I read this newsgroup everyday and learn something new everyday. Since I lack a degree in electrical engineering, I will be teaching myself that as well. I think many of you will be suprised at what a tenacious **** I am. Another graduate of Google university. Try doing it in steps. peace dawg |
#37
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Testing The Frequency Response Of A Room
Repliers,
Thank all of you for your help. I think I am on track now. Your collective experience saves me time and gets me to where I need to go fast. It is much appreciated. David |
#38
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Testing The Frequency Response Of A Room
On Mar 31, 5:43 pm, "AbsenceStudios" wrote:
I'm willing to pay three times the price for something that has any chance of giving me any sort of edge on my tracking and mixing. Three times the price of a Radio Shack SPL meter? Nope, that won't get you there. Three times the price of a Radio Shack meter wouldn't even buy the Fiberglas that everybody needs. Making a slightly more accurate measurement isn't going to help your tracking and mixing, because you can't fix it as accurately as you could measure it. As I said before, I've made a career choice. My goal is to deliver professional results and excellent customer service to clientelle. A noble goal. What are you starting from, and how much money have you got? If it's a bedroom and $200, you'd better stick to projects that you can get professional results using headphones. Since I lack a degree in electrical engineering, I will be teaching myself that as well. You really don't need to know a lot of electrical engineering. Ohm's Law will get you about as far there as you need to go. You do need to understand SYSTEM engineering, however. That's the study of gozintas and gozoutas and how to make them play nicely together. |
#39
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Testing The Frequency Response Of A Room
AbsenceStudios wrote:
"Scott Dorsey" wrote in message ... The RS meter is probably useful for relative measurements, but it's likely nowhere nearly as good as it could be for the price. True, but the next step up is the Pro-Tek which is three times the price. I'm willing to pay three times the price for something that has any chance of giving me any sort of edge on my tracking and mixing. It won't give you any edge, really. The room problems you're going to want to deal with first are problems that are so severe, when you play swept sine tones and move your head around the room, you're going to wonder how you even survived. Do that first, then worry about the rest of it. When you have room modes that are 25 dB from peak to trough, as is not unusual in a small room without bass trapping, making sure that your meter is accurate to within 3 dB is not very important. Play the sweep tones back, use your ears, move around, and you will immediately know what I'm talking about. --scott -- "C'est un Nagra. C'est suisse, et tres, tres precis." |
#40
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Testing The Frequency Response Of A Room
"Mike Rivers" wrote in message
... On Mar 31, 5:43 pm, "AbsenceStudios" wrote: As I said before, I've made a career choice. My goal is to deliver professional results and excellent customer service to clientelle. A noble goal. What are you starting from, and how much money have you got? If it's a bedroom and $200, you'd better stick to projects that you can get professional results using headphones. ========================= I don't have a budget worked out for acoustics yet--my price ceiling will probably end up being a little over $5,000. ========================= Since I lack a degree in electrical engineering, I will be teaching myself that as well. You really don't need to know a lot of electrical engineering. Ohm's Law will get you about as far there as you need to go. You do need to understand SYSTEM engineering, however. That's the study of gozintas and gozoutas and how to make them play nicely together. ========================= I'm an IT technician. Systems come naturally. |
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