|
Good sound card & software ?
What's a good reasonably priced sound card that would be good for doing
guitar waterfall, slab plots and FFTs and what software should I consider? Is there any good freeware or shareware? tnx -- 73 Hank WD5JFR |
Good sound card & software ?
"Henry Kolesnik" wrote in
message . net What's a good reasonably priced sound card that would be good for doing guitar waterfall, slab plots and FFTs and what software should I consider? Is there any good freeware or shareware? If your system board is only 1-3 years old, the audio interface that is built on it, makes a good starting point. |
Good sound card & software ?
On Feb 18, 9:48 am, "Henry Kolesnik"
wrote: What's a good reasonably priced sound card that would be good for doing guitar waterfall, slab plots and FFTs and what software should I consider? Is there any good freeware or shareware? tnx -- 73 Hank WD5JFR Pardon my ignorance, but what is a"slab plot"? It sounds architectural. |
Good sound card & software ?
On Sun, 18 Feb 2007 17:48:04 GMT, "Henry Kolesnik"
wrote: What's a good reasonably priced sound card that would be good for doing guitar waterfall, slab plots and FFTs and what software should I consider? Is there any good freeware or shareware? tnx Well, if you go to this site, you may find something interesting about all that you are looking for. This is a little bit much, . . But hey, with THX certification, it is going to give you a punch. http://www.creative.com/products/pro...roduct=112 26 |
Good sound card & software ?
Slab plots may not be the best term and it may be stack plots. Lets say
you have a plot of wave at time=o and another time=1 and so on. If you stack these plots offset a bit using a transparent medium you can see the wave as it decays over time. There's a good picture of this in the Hewlett Packard catalog in the description of the HP 3561A. The folders of Microsofts new Vista screen are a step in that direction. hank "videochas www.locoworks.com" wrote in message oups.com... On Feb 18, 9:48 am, "Henry Kolesnik" wrote: What's a good reasonably priced sound card that would be good for doing guitar waterfall, slab plots and FFTs and what software should I consider? Is there any good freeware or shareware? tnx -- 73 Hank WD5JFR Pardon my ignorance, but what is a"slab plot"? It sounds architectural. |
Good sound card & software ?
"Henry Kolesnik" wrote in message . net... What's a good reasonably priced sound card that would be good for doing guitar waterfall, slab plots and FFTs and what software should I consider? Is there any good freeware or shareware? tnx -- 73 Hank WD5JFR RME http://www.rme-audio.com/english/soundcds.htm |
Good sound card & software ?
On Sun, 18 Feb 2007 17:48:04 GMT, "Henry Kolesnik"
wrote: What's a good reasonably priced sound card that would be good for doing guitar waterfall, slab plots and FFTs and what software should I consider? Is there any good freeware or shareware? tnx Can't help you with the slab plots or waterfalls, but my Daqarta shareware has color spectrograms, as well as spectra and waveform displays, signal averaging, signal generation, etc. FFT size is 1024 points, so you won't be able to use this for tuning your guitar, if that's what you had in mind. I'm in the process of adding a high-resolution FFT peak position interpolator that might or might not help that... it won't separate close peaks, though. I'd be glad to answer any questions. Best regards, Bob Masta D A Q A R T A Data AcQuisition And Real-Time Analysis www.daqarta.com Scope, Spectrum, Spectrogram, Signal Generator Science with your sound card! |
Good sound card & software ?
Bob
I sent an eamil to your site and asked them to send it to you becasue I couldn't figure your address. -- 73 Hank WD5JFR "Bob Masta" wrote in message ... On Sun, 18 Feb 2007 17:48:04 GMT, "Henry Kolesnik" wrote: What's a good reasonably priced sound card that would be good for doing guitar waterfall, slab plots and FFTs and what software should I consider? Is there any good freeware or shareware? tnx Can't help you with the slab plots or waterfalls, but my Daqarta shareware has color spectrograms, as well as spectra and waveform displays, signal averaging, signal generation, etc. FFT size is 1024 points, so you won't be able to use this for tuning your guitar, if that's what you had in mind. I'm in the process of adding a high-resolution FFT peak position interpolator that might or might not help that... it won't separate close peaks, though. I'd be glad to answer any questions. Best regards, Bob Masta D A Q A R T A Data AcQuisition And Real-Time Analysis www.daqarta.com Scope, Spectrum, Spectrogram, Signal Generator Science with your sound card! |
Good sound card & software ?
|
Good sound card & software ?
There's a good example of a 3D plot he
http://www.spectraplus.com/screenshots.html#3d Has anyone used this software? tnx -- 73 Hank WD5JFR "Richard Clark" wrote in message ... On Mon, 19 Feb 2007 14:06:30 GMT, (Bob Masta) wrote: FFT size is 1024 points, so you won't be able to use this for tuning your guitar, if that's what you had in mind. Hi Bob, Why not? 1024 points (bins) has enough resolution to shake out every note on a Hawaiian slide guitar. The only care is selecting the sampling rate and most FFT packages should be able to resolve exceedingly fine. 73's Richard Clark, KB7QHC |
Good sound card & software ?
"Henry Kolesnik" wrote in
message . net There's a good example of a 3D plot he http://www.spectraplus.com/screenshots.html#3d Has anyone used this software? Yes, but not for exactly that purpose. Here's a sample of my usage of Spectra: http://www.pcavtech.com/soundcards/lynxtwo/ |
Good sound card & software ?
On Mon, 19 Feb 2007 15:16:29 -0600, "Henry Kolesnik"
wrote: There's a good example of a 3D plot he http://www.spectraplus.com/screenshots.html#3d Has anyone used this software? Hi Hank, Yes, I have. It is exceedingly expensive, but you can probably get 30 days of free use if you have a one-time knock off project. Of course, it may take 30 days to figure it out. FFT analyzers are a dime a dozen, but few know how to use them accurately - or are even aware of what can be done with them. Bob's complaint, notwithstanding, a 1024 bin FFT employing the proper mixing inputs can resolve any note on a guitar to within hundredths of a cycle. I am sure this is of no interest to you, however. What are you trying to measure? The dime a dozen analyzers (meaning free, or packaged with other software) can do enough if you are not particularly demanding. 73's Richard Clark, KB7QHC |
Good sound card & software ?
"Richard Clark" wrote in message
On Mon, 19 Feb 2007 15:16:29 -0600, "Henry Kolesnik" wrote: There's a good example of a 3D plot he http://www.spectraplus.com/screenshots.html#3d Has anyone used this software? Hi Hank, Yes, I have. It is exceedingly expensive, but you can probably get 30 days of free use if you have a one-time knock off project. Of course, it may take 30 days to figure it out. FFT analyzers are a dime a dozen, but few know how to use them accurately - or are even aware of what can be done with them. Bob's complaint, notwithstanding, a 1024 bin FFT employing the proper mixing inputs can resolve any note on a guitar to within hundredths of a cycle. I am sure this is of no interest to you, however. Over the years, the most useful FFT software I've had, is the (fairly simple) FFT analyzer in Audition/CEP. It's big plus is the ability to use the Audition/CEP audio editor to select portions of real-world waveforms, and to use the wave generation and modification features to create waves for use in analysis and testing. |
Good sound card & software ?
On Mon, 19 Feb 2007 17:23:32 -0500, "Arny Krueger"
wrote: Over the years, the most useful FFT software I've had, is the (fairly simple) FFT analyzer in Audition/CEP. It's big plus is the ability to use the Audition/CEP audio editor to select portions of real-world waveforms, and to use the wave generation and modification features to create waves for use in analysis and testing. Hi Arny, I am sure this is an useful tool, but without windowing the data, any semblance to reasonable analysis is a house built on sand. I note in your provided link to work you have done that you use Blackman exclusively. This is at least a good first pass to achieving an analysis, but any variety of work is going to be more demanding (the Blackman window has its limitations), otherwise it is like looking through glasses smeared with Vaseline. 73's Richard Clark, KB7QHC |
Good sound card & software ?
Amy, Bob, Richard
Thanks for your response and interest. I'm retired used to be an engineer before management laid waste to that. I've started taking weekly guitar lessons over a year ago and slowly getting a bit better. It's a hell of a challenge at 66. I want to buy a better guitar and all guitars don't sound the same, even the same model. One shouldn't expect them to because they're all made from different cuts of wood and assembled by human hands. What amazed me is that the materials used for the nut, neck, saddle and bridge as well as the mfg and age of the strings have a noticeable effect on the sound. The bridge pins, angle of the strings out of the bridge pin holes and tuners also have effects. In the last year I found at least four guitars that I really liked, 3 used ones and a new one all over a $1000.00 but I passed because I'm not that impulsive or flush with cash. A good player can make just about any guitar sound good, or a hell of a lot better than me. I'm into ham radio also and last year at hamfest I traded for an HP 3582A spectrum analyzer but the learning curve is a bit steep for me. So unless I can find an experienced user or devote much more time to it I'm going to have to trade it. Last week I won an HP 3561A on ePay but it has a problem that I hope I can fix. In the meantime I thought it might make sense to scope out sound cards and related software. I know a lot of hams use sound cards for various & different applications and it's about time I took a wack at one and what better way than trying to figure out what it is that makes one guitar sound so much better than another. Or if changing the nut, saddle or bridge pins really improves the sound or is it just wishful thinking. And I can make use of it for ham radio weak signal detection and analysis. I used a term; slab diagrams which may be known as stack diagrams. I'm interested in watching a plucked and later chords as they decay over time in sort of a 3D plot. There's a good example of what I'm looking for in the HP catalog describing the HP 3561A. tnx 73 Hank WD5JFR "Richard Clark" wrote in message ... On Mon, 19 Feb 2007 15:16:29 -0600, "Henry Kolesnik" wrote: There's a good example of a 3D plot he http://www.spectraplus.com/screenshots.html#3d Has anyone used this software? Hi Hank, Yes, I have. It is exceedingly expensive, but you can probably get 30 days of free use if you have a one-time knock off project. Of course, it may take 30 days to figure it out. FFT analyzers are a dime a dozen, but few know how to use them accurately - or are even aware of what can be done with them. Bob's complaint, notwithstanding, a 1024 bin FFT employing the proper mixing inputs can resolve any note on a guitar to within hundredths of a cycle. I am sure this is of no interest to you, however. What are you trying to measure? The dime a dozen analyzers (meaning free, or packaged with other software) can do enough if you are not particularly demanding. 73's Richard Clark, KB7QHC |
Good sound card & software ?
In article ,
"Henry Kolesnik" wrote: Amy, Bob, Richard Thanks for your response and interest. I'm retired used to be an engineer before management laid waste to that. I've started taking weekly guitar lessons over a year ago and slowly getting a bit better. It's a hell of a challenge at 66. I want to buy a better guitar and all guitars don't sound the same, even the same model. One shouldn't expect them to because they're all made from different cuts of wood and assembled by human hands. What amazed me is that the materials used for the nut, neck, saddle and bridge as well as the mfg and age of the strings have a noticeable effect on the sound. The bridge pins, angle of the strings out of the bridge pin holes and tuners also have effects. In the last year I found at least four guitars that I really liked, 3 used ones and a new one all over a $1000.00 but I passed because I'm not that impulsive or flush with cash. A good player can make just about any guitar sound good, or a hell of a lot better than me. I'm into ham radio also and last year at hamfest I traded for an HP 3582A spectrum analyzer but the learning curve is a bit steep for me. So unless I can find an experienced user or devote much more time to it I'm going to have to trade it. Last week I won an HP 3561A on ePay but it has a problem that I hope I can fix. In the meantime I thought it might make sense to scope out sound cards and related software. I know a lot of hams use sound cards for various & different applications and it's about time I took a wack at one and what better way than trying to figure out what it is that makes one guitar sound so much better than another. Or if changing the nut, saddle or bridge pins really improves the sound or is it just wishful thinking. What a neat project! I can tell you, based on years of experience with changing out the parts that you mentioned (nut, saddle, bridge, pins, ESPECIALLY break angle) that these things DO make a difference in the sound. I have NOT heard a difference with changes of neck or tuners (certainly these things affect the intonation of the instrument, but I've never known then to change the quality of sound). However, the choice of wood, body shape, and top bracing are far more relevant. You might want to check with Martin, Taylor, Larrivee, et al to see if they have any scientific info that can help you. They aren't in the business of pushing pins, tuners, etc. Good luck and please post what you find out! (Since this is RAO, I should point out that my hearing of the things mentioned in my second paragraph above is based on differences heard based on changes made to the instruments when it wasn't possible to know about the changes.) |
Good sound card & software ?
Jenn
The neck wood affects the sound energy as it goes from the nut vibrate the guitar and so does the truss rod. Tuners can influence the sound because their weight can dampen vibrations. An interesting thing is to hold a tuner lightly ( or the headstock) when you pluck a string and feel the vibrations. A good analysis should be able to detect loose bracing and you should also be able to see the effects of scalloped bracing. I shotgunned this query because I didn't know where I would find the most help. If responders can suggest a group I could limit it and not waste time of those who aren't interested. I've also made unconnected posts to other groups, but have less interest and reponse so far. I didn't post to any guitar groups because most there are musicians that don't need this kind of crutch and have an ear that's been trained for many years. I want to see if I can catch up by being able to see. In addition it should be helpful in voice training which I also need because I'm trying but with less success to sing. 73 Hank WD5JFR "Jenn" wrote in message ... In article , "Henry Kolesnik" wrote: Amy, Bob, Richard Thanks for your response and interest. I'm retired used to be an engineer before management laid waste to that. I've started taking weekly guitar lessons over a year ago and slowly getting a bit better. It's a hell of a challenge at 66. I want to buy a better guitar and all guitars don't sound the same, even the same model. One shouldn't expect them to because they're all made from different cuts of wood and assembled by human hands. What amazed me is that the materials used for the nut, neck, saddle and bridge as well as the mfg and age of the strings have a noticeable effect on the sound. The bridge pins, angle of the strings out of the bridge pin holes and tuners also have effects. In the last year I found at least four guitars that I really liked, 3 used ones and a new one all over a $1000.00 but I passed because I'm not that impulsive or flush with cash. A good player can make just about any guitar sound good, or a hell of a lot better than me. I'm into ham radio also and last year at hamfest I traded for an HP 3582A spectrum analyzer but the learning curve is a bit steep for me. So unless I can find an experienced user or devote much more time to it I'm going to have to trade it. Last week I won an HP 3561A on ePay but it has a problem that I hope I can fix. In the meantime I thought it might make sense to scope out sound cards and related software. I know a lot of hams use sound cards for various & different applications and it's about time I took a wack at one and what better way than trying to figure out what it is that makes one guitar sound so much better than another. Or if changing the nut, saddle or bridge pins really improves the sound or is it just wishful thinking. What a neat project! I can tell you, based on years of experience with changing out the parts that you mentioned (nut, saddle, bridge, pins, ESPECIALLY break angle) that these things DO make a difference in the sound. I have NOT heard a difference with changes of neck or tuners (certainly these things affect the intonation of the instrument, but I've never known then to change the quality of sound). However, the choice of wood, body shape, and top bracing are far more relevant. You might want to check with Martin, Taylor, Larrivee, et al to see if they have any scientific info that can help you. They aren't in the business of pushing pins, tuners, etc. Good luck and please post what you find out! (Since this is RAO, I should point out that my hearing of the things mentioned in my second paragraph above is based on differences heard based on changes made to the instruments when it wasn't possible to know about the changes.) |
Good sound card & software ?
On Tue, 20 Feb 2007 05:27:17 GMT, Jenn
wrote: (Since this is RAO, I should point out that my hearing of the things mentioned in my second paragraph above is based on differences heard based on changes made to the instruments when it wasn't possible to know about the changes.) Eh? |
Good sound card & software ?
On Mon, 19 Feb 2007 10:34:50 -0800, Richard Clark
wrote: On Mon, 19 Feb 2007 14:06:30 GMT, (Bob Masta) wrote: FFT size is 1024 points, so you won't be able to use this for tuning your guitar, if that's what you had in mind. Hi Bob, Why not? 1024 points (bins) has enough resolution to shake out every note on a Hawaiian slide guitar. The only care is selecting the sampling rate and most FFT packages should be able to resolve exceedingly fine. The problem is that the line resolution of an FFT is the sample rate divided by the number of time points. So with 44100 Hz sample rate and 1024 points you get a bit over 43 Hz per line. So the first non-DC spectral line would be 43 Hz, which is about a low F on a bass guitar, and the very next line would be the F an octave above that... you'd miss an entire octave! The standard musical note frequencies (semitones) differ from each other by about 6% (12th root of 2, since there are 12 notes in an "octave"). But you need much better resolution than this for tuning, typically a "cent" or so, namely 1/100 of a semitone or .06%. At 43 Hz that works out to about 0.026 Hz. A 64K-point FFT at 44100 Hz will have a native resolution of 0.67 Hz, which still isn't good enough... but at 64K samples, you are looking at 1.48 seconds of sound. If the pitch changes over that interval, the spectral peak will be smeared even further. If you attempt to beat this game by going to lower sample rates, note that frequency resolution is still proportional to the inverse of the total sampling interval. So if you tried to use the 1K FFT but sample at 44100 / 64 = 689 Hz to get the same (inadequate) resolution as the above 64K FFT, you'd still need 1.48 seconds of sound. Sound cards don't sample that low intrinsically (typically 8K lower limit, 4K on old Sound Blasters), but you might manage using sample rate conversion (either Windows or sound card built-in). I haven't tried this, but I suspect that it would not be a satisfying experience due to the s-l-o-w time response. Best regards, Bob Masta D A Q A R T A Data AcQuisition And Real-Time Analysis www.daqarta.com Scope, Spectrum, Spectrogram, Signal Generator Science with your sound card! |
Good sound card & software ?
On Mon, 19 Feb 2007 14:08:54 -0800, Richard Clark
wrote: On Mon, 19 Feb 2007 15:16:29 -0600, "Henry Kolesnik" wrote: There's a good example of a 3D plot he http://www.spectraplus.com/screenshots.html#3d Has anyone used this software? Hi Hank, Yes, I have. It is exceedingly expensive, but you can probably get 30 days of free use if you have a one-time knock off project. Of course, it may take 30 days to figure it out. FFT analyzers are a dime a dozen, but few know how to use them accurately - or are even aware of what can be done with them. Bob's complaint, notwithstanding, a 1024 bin FFT employing the proper mixing inputs can resolve any note on a guitar to within hundredths of a cycle. I am sure this is of no interest to you, however. Yes, you can easily resolve to 100ths of a cycle, but not from a native FFT. (See my other response.) You can do it from the waveform by measuring the time between cycles. That's one of the methods I'm working on. The other is to do it from the FFT via peak interpolation. The waveform method will be very accurate with simple static waveforms, but I expect it will have trouble with the 2nd harmonic of a plucked string, which is not an integer multiple so "rolls" through the waveform. The FFT interpolator will not have the same raw accuracy, and must have absolutely separated spectral peaks since it assumes the one it's interpolating is the only one. I'm not hopeful it can be made good enough to tune a guitar, at least not in the bottom octave where the harmonics land on adjacent spectral lines. Best regards, Bob Masta D A Q A R T A Data AcQuisition And Real-Time Analysis www.daqarta.com Scope, Spectrum, Spectrogram, Signal Generator Science with your sound card! |
Good sound card & software ?
"paul packer" wrote in message
On Tue, 20 Feb 2007 05:27:17 GMT, Jenn wrote: (Since this is RAO, I should point out that my hearing of the things mentioned in my second paragraph above is based on differences heard based on changes made to the instruments when it wasn't possible to know about the changes.) Eh? Jenn apparently thinks that the changes in SQ that come from modifying the working parts of musical instruments are fully comparable to say, adding one more strand of wire to a speaker cable composed of finely stranded wilre. |
Good sound card & software ?
"Richard Clark" wrote in message
On Mon, 19 Feb 2007 17:23:32 -0500, "Arny Krueger" wrote: Over the years, the most useful FFT software I've had, is the (fairly simple) FFT analyzer in Audition/CEP. It's big plus is the ability to use the Audition/CEP audio editor to select portions of real-world waveforms, and to use the wave generation and modification features to create waves for use in analysis and testing. I am sure this is an useful tool, but without windowing the data, any semblance to reasonable analysis is a house built on sand. So you think that the FFT analysis tool in CEP doesn't do windowing????? I note in your provided link to work you have done that you use Blackman exclusively. This is at least a good first pass to achieving an analysis, but any variety of work is going to be more demanding (the Blackman window has its limitations), otherwise it is like looking through glasses smeared with Vaseline. So you think that Spectra doesn't provide options for windowing and/or that I have no idea what effect they have on actual results???? |
Good sound card & software ?
In article ,
"Henry Kolesnik" wrote: Jenn The neck wood affects the sound energy as it goes from the nut vibrate the guitar and so does the truss rod. True; I was thinking of the neck shape. The question is, of course, can one hear the difference between different neck woods on the same instrument body. Tuners can influence the sound because their weight can dampen vibrations. But can one hear the difference between different tuners? I seriously doubt it. An interesting thing is to hold a tuner lightly ( or the headstock) when you pluck a string and feel the vibrations. But can you hear the tone quality change as you hold the tuners? I can't detect that difference on any of my instruments. A good analysis should be able to detect loose bracing and you should also be able to see the effects of scalloped bracing. Indeed. I shotgunned this query because I didn't know where I would find the most help. If responders can suggest a group I could limit it and not waste time of those who aren't interested. I've also made unconnected posts to other groups, but have less interest and reponse so far. I didn't post to any guitar groups because most there are musicians that don't need this kind of crutch and have an ear that's been trained for many years. I want to see if I can catch up by being able to see. In addition it should be helpful in voice training which I also need because I'm trying but with less success to sing. If you go to rec.music.makers.guitar.acoustic, you'll find several outstanding luthiers there who may be able to offer help. And though I don't hang out there, rec.music.makers.builders might also include similar folks. Good luck, Hank! 73 Hank WD5JFR "Jenn" wrote in message ... In article , "Henry Kolesnik" wrote: Amy, Bob, Richard Thanks for your response and interest. I'm retired used to be an engineer before management laid waste to that. I've started taking weekly guitar lessons over a year ago and slowly getting a bit better. It's a hell of a challenge at 66. I want to buy a better guitar and all guitars don't sound the same, even the same model. One shouldn't expect them to because they're all made from different cuts of wood and assembled by human hands. What amazed me is that the materials used for the nut, neck, saddle and bridge as well as the mfg and age of the strings have a noticeable effect on the sound. The bridge pins, angle of the strings out of the bridge pin holes and tuners also have effects. In the last year I found at least four guitars that I really liked, 3 used ones and a new one all over a $1000.00 but I passed because I'm not that impulsive or flush with cash. A good player can make just about any guitar sound good, or a hell of a lot better than me. I'm into ham radio also and last year at hamfest I traded for an HP 3582A spectrum analyzer but the learning curve is a bit steep for me. So unless I can find an experienced user or devote much more time to it I'm going to have to trade it. Last week I won an HP 3561A on ePay but it has a problem that I hope I can fix. In the meantime I thought it might make sense to scope out sound cards and related software. I know a lot of hams use sound cards for various & different applications and it's about time I took a wack at one and what better way than trying to figure out what it is that makes one guitar sound so much better than another. Or if changing the nut, saddle or bridge pins really improves the sound or is it just wishful thinking. What a neat project! I can tell you, based on years of experience with changing out the parts that you mentioned (nut, saddle, bridge, pins, ESPECIALLY break angle) that these things DO make a difference in the sound. I have NOT heard a difference with changes of neck or tuners (certainly these things affect the intonation of the instrument, but I've never known then to change the quality of sound). However, the choice of wood, body shape, and top bracing are far more relevant. You might want to check with Martin, Taylor, Larrivee, et al to see if they have any scientific info that can help you. They aren't in the business of pushing pins, tuners, etc. Good luck and please post what you find out! (Since this is RAO, I should point out that my hearing of the things mentioned in my second paragraph above is based on differences heard based on changes made to the instruments when it wasn't possible to know about the changes.) |
Good sound card & software ?
On Tue, 20 Feb 2007 09:58:34 -0500, "Arny Krueger"
wrote: "paul packer" wrote in message On Tue, 20 Feb 2007 05:27:17 GMT, Jenn wrote: (Since this is RAO, I should point out that my hearing of the things mentioned in my second paragraph above is based on differences heard based on changes made to the instruments when it wasn't possible to know about the changes.) Eh? Jenn apparently thinks that the changes in SQ that come from modifying the working parts of musical instruments are fully comparable to say, adding one more strand of wire to a speaker cable composed of finely stranded wilre. I don't know what Jenn said, but I do know that you don't know either. |
Good sound card & software ?
|
Good sound card & software ?
On Tue, 20 Feb 2007 10:01:08 -0500, "Arny Krueger"
wrote: So you think that the FFT analysis tool in CEP doesn't do windowing????? With about as much panache as a Yugo in the Indy 500. Hardly a reason to throw $350 into the wind. So you think that Spectra doesn't provide options for windowing and/or that I have no idea what effect they have on actual results???? The designer of Spectra is a local Ham - I know his capabilities, I don't know yours. All I have to go on is the pedestrian choice of Blackman windowing that demonstrates nothing in the way of "ideas on the effect on actual results." As I offered, it is an ordinarily suitable choice if you have no demanding requirements. Hi Hank, There are a world of free analyzers, one quick search found 16: http://freshmeat.net/search/?q=fft&s...o.x=11&Go.y=10 Get your feet wet before throwing the green at bloatware designs that invest their resources in advertising. If you find nothing in this first list, I can certainly 26 find more. 73's Richard Clark, KB7QHC |
Good sound card & software ?
"Richard Clark" wrote in message
On Tue, 20 Feb 2007 10:01:08 -0500, "Arny Krueger" wrote: So you think that the FFT analysis tool in CEP doesn't do windowing????? With about as much panache as a Yugo in the Indy 500. Hardly a reason to throw $350 into the wind. So you think that Spectra doesn't provide options for windowing and/or that I have no idea what effect they have on actual results???? The designer of Spectra is a local Ham - I know his capabilities, I don't know yours. All I have to go on is the pedestrian choice of Blackman windowing that demonstrates nothing in the way of "ideas on the effect on actual results." As I offered, it is an ordinarily suitable choice if you have no demanding requirements. I got it now, I'm dealing with a FFT snob, not someone who just sees them as a tool to get a job done. |
Good sound card & software ?
"paul packer" wrote in message
On Tue, 20 Feb 2007 09:58:34 -0500, "Arny Krueger" wrote: "paul packer" wrote in message On Tue, 20 Feb 2007 05:27:17 GMT, Jenn wrote: (Since this is RAO, I should point out that my hearing of the things mentioned in my second paragraph above is based on differences heard based on changes made to the instruments when it wasn't possible to know about the changes.) Eh? Jenn apparently thinks that the changes in SQ that come from modifying the working parts of musical instruments are fully comparable to say, adding one more strand of wire to a speaker cable composed of finely stranded wilre. I don't know what Jenn said, but I do know that you don't know either. Paul, you keep missing the meaning of words that I wrote - this time the word you missed is "apparently". |
Good sound card & software ?
On Tue, 20 Feb 2007 23:02:18 -0500, "Arny Krueger"
wrote: The designer of Spectra is a local Ham - I know his capabilities, I don't know yours. All I have to go on is the pedestrian choice of Blackman windowing that demonstrates nothing in the way of "ideas on the effect on actual results." As I offered, it is an ordinarily suitable choice if you have no demanding requirements. I got it now, I'm dealing with a FFT snob, not someone who just sees them as a tool to get a job done. Connoisseur is more appropriate, and as for getting the job done, I did that on contract to HP for one of their many FFT audio analyzers 22 years ago. I've written 200,000 lines of fourier code for many products that get jobs done. I also have the seminal work by Blackman and Tukey that predates the math of the Fourier transform: "The Measurement of Power Spectra." An extract bears repeating: "'... we were able to discover in the general wave record a very weak low-frequency peak which would surely have escaped our attention without spectral analysis. This peak, it turns out, is almost certainly due to a swell from the Indian Ocean, 10,000 miles distant. Physical dimensions a 1mm high and a kilometer long.'" The Hann or Hamm windowing functions are preferable as even Blackman would admit and even these two are hardly exemplars of outstanding performance. My designs exhibited a noise floor of -200dB (statistical noise from the transcendentals' math). A poor Blackman window would throw away 120dB of that to offer only -80dB. -80dB is certainly impressive to mundane applications, but most would agree that very little more effort was needed to gain 12 more orders of magnitude in performance. Hi Hank, If you've waded through my prior list of freely available Fourier analyzers, more can be found at: http://sourceforge.net/search/?type_...soft&words=fft Not all are applications however. However, you should probably try to get a copy of HP's Application Note 243-1 "Dynamic Signal Analyzer Applications." Of particular note for your studies into the nuances of investigating construction materials in Guitars (I did it with Violins), you should study the Fourier math relating to "Coherence" suited for a dual channel analyzer. 73's Richard Clark, KB7QHC |
Good sound card & software ?
On Tue, 20 Feb 2007 23:03:10 -0500, "Arny Krueger"
wrote: I don't know what Jenn said, but I do know that you don't know either. Paul, you keep missing the meaning of words that I wrote Shouldn't that be "words that I've written"? There could be an inherent explanation here. |
Good sound card & software ?
On Tue, 20 Feb 2007 14:04:19 GMT, (Bob Masta)
wrote: On Mon, 19 Feb 2007 10:34:50 -0800, Richard Clark wrote: On Mon, 19 Feb 2007 14:06:30 GMT, (Bob Masta) wrote: FFT size is 1024 points, so you won't be able to use this for tuning your guitar, if that's what you had in mind. Hi Bob, Why not? 1024 points (bins) has enough resolution to shake out every note on a Hawaiian slide guitar. The only care is selecting the sampling rate and most FFT packages should be able to resolve exceedingly fine. The problem is that the line resolution of an FFT is the sample rate divided by the number of time points. So with 44100 Hz sample rate and 1024 points you get a bit over 43 Hz per line. So the first non-DC spectral line would be 43 Hz, which is about a low F on a bass guitar, and the very next line would be the F an octave above that... you'd miss an entire octave! Hi Bob, What you describe here, and that which followed, is a problem of either hardware (I design my own) or a perception of Fourier techniques that is constrained to common applications. The trick is one that is encountered quite commonly with RF designers (and those Hams that actually practice the craft instead of being appliance operators) - it is called mixing. Or to describe it with more precision (as an audio crowd has a restricted meaning for the term "mixing") heterodyning or modulating/demodulating. Simply put, the data channel is pre-processed by multiplying it with a reference cosine before being passed onto the FFT. (Although this sounds like windowing, it is not.) Of course, the output of the FFT has to have its units recast. In the old days, this was called "zooming" or an arbitrary view of a single frequency encompassed by a span of far higher resolution than that obtained from a simple transform. I would quickly point out that the simple transform is still performed (same bin interval, same bin count), but it has been augmented. This technique, plus a waterfall display, is useful in tracing down mechanical problems in journals, bearing races (with bearing run-out or ball defect) and bad gear meshes. It also relates to Hank's desire to test individual construction components in the guitar as all of these problems relate to a subtle data inflection that can be destructive in machinery, or discordant in music. The zoom feature can reveal these defects with remarkable resolution. As I said, the FFT as originally described can differentiate every note of an Hawaiian slide guitar. Perhaps I should have added the proviso: provided you use a synchronized tracking generator for mixing. However, given this can be done digitally (no one needs a hardware oscillator), no change in hardware is necessary. All the data that is needed is already there. www.daqarta.com by the way, this seems to be a dead link. (later) I take that back, but it took a lot of retries over the span of an hour. Further, it seems you have a lot of what I mention above covered in your pages, by parts, but none of them encompass the whole of "zooming." And for your page on windowing, drop me an email if you would like to see some pascal routines embodying some very tight windows. These came from my time with HP whose chief engineer soon after departed for a chair at some eastern university. 73's Richard Clark, KB7QHC |
Good sound card & software ?
On Wed, 21 Feb 2007 23:47:39 -0800, Richard Clark
wrote: On Tue, 20 Feb 2007 14:04:19 GMT, (Bob Masta) wrote: On Mon, 19 Feb 2007 10:34:50 -0800, Richard Clark wrote: On Mon, 19 Feb 2007 14:06:30 GMT, (Bob Masta) wrote: FFT size is 1024 points, so you won't be able to use this for tuning your guitar, if that's what you had in mind. Hi Bob, Why not? 1024 points (bins) has enough resolution to shake out every note on a Hawaiian slide guitar. The only care is selecting the sampling rate and most FFT packages should be able to resolve exceedingly fine. The problem is that the line resolution of an FFT is the sample rate divided by the number of time points. So with 44100 Hz sample rate and 1024 points you get a bit over 43 Hz per line. So the first non-DC spectral line would be 43 Hz, which is about a low F on a bass guitar, and the very next line would be the F an octave above that... you'd miss an entire octave! Hi Bob, What you describe here, and that which followed, is a problem of either hardware (I design my own) or a perception of Fourier techniques that is constrained to common applications. The trick is one that is encountered quite commonly with RF designers (and those Hams that actually practice the craft instead of being appliance operators) - it is called mixing. Or to describe it with more precision (as an audio crowd has a restricted meaning for the term "mixing") heterodyning or modulating/demodulating. Simply put, the data channel is pre-processed by multiplying it with a reference cosine before being passed onto the FFT. (Although this sounds like windowing, it is not.) Of course, the output of the FFT has to have its units recast. In the old days, this was called "zooming" or an arbitrary view of a single frequency encompassed by a span of far higher resolution than that obtained from a simple transform. I would quickly point out that the simple transform is still performed (same bin interval, same bin count), but it has been augmented. This technique, plus a waterfall display, is useful in tracing down mechanical problems in journals, bearing races (with bearing run-out or ball defect) and bad gear meshes. It also relates to Hank's desire to test individual construction components in the guitar as all of these problems relate to a subtle data inflection that can be destructive in machinery, or discordant in music. The zoom feature can reveal these defects with remarkable resolution. As I said, the FFT as originally described can differentiate every note of an Hawaiian slide guitar. Perhaps I should have added the proviso: provided you use a synchronized tracking generator for mixing. However, given this can be done digitally (no one needs a hardware oscillator), no change in hardware is necessary. All the data that is needed is already there. www.daqarta.com by the way, this seems to be a dead link. (later) I take that back, but it took a lot of retries over the span of an hour. Further, it seems you have a lot of what I mention above covered in your pages, by parts, but none of them encompass the whole of "zooming." And for your page on windowing, drop me an email if you would like to see some pascal routines embodying some very tight windows. These came from my time with HP whose chief engineer soon after departed for a chair at some eastern university. 73's Richard Clark, KB7QHC Richard: Thanks for your detailed post. I am aware of the "zoom" approach, but have not implemented it yet. The cosine multiplication down to baseband is the easy part; the part that has put me off is the pesky decimating filter. For others reading this, the basic idea of the zoom FFT is that if you want to "zoom in on" some frequency region at higher resolution, you multiply the incoming signal by the center of the desired range. From that old high school trig formula for the product of sinusoids, you get a bunch of sum and difference components. So the center of the target band ends up at 0 Hz since you multiplied it by a sinusoid at the center frequency, and all the rest of the original spectrum is now spreading out on either side of 0. Now, if you low-pass filter this mess you can re-sample it at a much lower frequency. The filter has to be set so there is nothing of significance above half of the new sample rate, just as for the orignal ADC (or you get aliasing errors). Then you take an FFT of the same size (1024 or whatever) samples, but at the new lower sample rate. If the new rate is 1/100 of the original, the resolution of the spectrum is improved x100. Another way to think about this is that if you only wanted to zoom in on the low end of the spectrum, you wouldn't need to do the cosine multiply, filter, or resampling... you could just reduce the base sample rate to 1/100 (if your sound card permitted, and had its anti-alias filters set for that) and get exactly the same results. Note that this gives exactly the same resolution as an FFT that is x100 larger, where you only get to see 1/100 of the whole spectrum. Also note that an x100 increase in resolution takes x100 increase in sample time, so you must insure that the signal is stable over that interval or you will get spectral peak smearing... there is no free lunch here! This is no problem for Richard's examples of bearings and gear meshes, but I'd expect troubles with most music since it is so dynamic. Anyway, back to my original lament: The low-pass filtering and resampling would be quite inefficient if done by conventional approaches, but there are apparently some elegant solutions that do both functions in one block, reusing it over and over to get successive halvings of the sample rate. My problem is that I have only seen this described in theoretical terms with simple block diagrams, leaving the exact coefficients, etc, as "an excercise for the reader". Searching the Web I find that others are apparently as left out in the cold by this as I am, and there is no example code, hints, or tips to be found. So, until this particular reader either gets struck by a flash of insight or takes the time to read up on this enough to get a whole lot smarter, the zoom FFT is on a back burner. (Richard, I'll Email you about those window routines... many thanks for the offer!) Best regards, Bob Masta D A Q A R T A Data AcQuisition And Real-Time Analysis www.daqarta.com Scope, Spectrum, Spectrogram, Signal Generator Science with your sound card! |
Good sound card & software ?
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