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What is chromatic whistling? this is something I saw on the Phoenix website and am curious what it is.
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Re: What is "Chromatic Whistling"?
Where on their website did you see it? Just wondering if there is some context they placed around that term to help figure out what it means. -
Re: What is "Chromatic Whistling"?
Quote from Phoenix Website:
"The use of multiple samples also avoids the "chromatic whistling" effect which seriously flaws the sound if too few samples are used."
Sounds to me that its something to do with the resonance you get when you pitch shift a tone rather then have two separate samples.
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Re: What is "Chromatic Whistling"?
Maybe they're talking about digital Aliasing which is distortion occuring when the sample or harmonics thereof approach 1/2 the sample rate. This is a limiting factor in digital audio or video systems. Nowadays it's not really a problem since modern IC's allow high data rates.</P>
Maybe they're talking about assigning different channels to ajacent notes like C on channel 1 and C# on channel 2 and so on. Like Diatonic pipe placement where ajacent notes are on opposite ends of the chest. It supposidly gives a more spacious sound. Allen and others use this technique. Lots of Amps and speakers.</P>
My chests are Chromatic and the pipes Whistle but I think they're supposed to do that. Any ideas? </P>
Maybe someone from Phoenix can enlighten us.</P>
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Re: What is "Chromatic Whistling"?
al,
Organgrinder has said what it means. Basically a sample when played back should be played back at the proper pitch. If the sample is used more than say half an octave you start getting artifacts, one of which is this chromatic whisting. It is most objectionable in lower registers where builders try to add say a 32' octave to a 16' stop just running the lowest octave on the same sample. Basically the more samples used across the compass the better. Best is a sample for each note.
Aliasing is a problem relating more to the top end. It relates to the frequency of a sample compared to the sampling rate. The difference between the two frequencies have to be filtered, or you get one wierd sound. Problem with anti-aliasing filters, is that they neuter high frequency content in the tone of the samples as well. That is why the top end of most digital organs have this sort of mono-colour or lack of "sparkle". In other words the tone sounds dried out compared to real pipes. This is a tone problem, not a volume issue. Higher sampling rates, such as 100Khz or higher is one answer to the problem. Doing that however means using costly hardware, and is much more memory intensive.
The best digi organs today use lots of samples, high sampling rates, samples that are long, and then put it through multi channel audio systems. By multi channel, I don't mean 2 or 4 channels but more like 8 or more for a small organ, or at least a dozen, preferrably more than 20 on larger instruments. In other words, doing it right means higher cost.
av
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Re: What is "Chromatic Whistling"?
Ok so what they're doing is like playing each point on the sample phase twice to halve the pitch. Like stretching the sample. </P>
Let me ask a slightly different issue. How do you synchronize the trem phase of tremmed samples? I have a nice Tibia with trem that sounds nice with individual notes but with multiple notes at different times it sounds bad as each note is at a diufferent trem phase. How can you keep them all in phase? I assume a phase reference has to accompany the sample so that all notes turn on in phase? How do they do it?? Sure I add trem to the replay audio but that's just not the same.</P>Comment
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Re: What is "Chromatic Whistling"?
Chromatic whistling is when your monochrome TV makes whistling sounds on channels with nothing but snow.[:D]Comment
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Re: What is "Chromatic Whistling"?
The only way I can figure, is they have every sample loaded in sync from the get-go. How they oscillate in sync? Maybe like a hammond organ; additive systhesis? I can see if the sound is being synthesized, this would be a simple LFO patch, but using samples... Its not very obvious.
Honestly, I have been trying to figure this out myself. I have a soundfont (from a Barton) that has a few tremolo tibias and vox humanas that are in sync, but I don't know how it works.
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Re: What is "Chromatic Whistling"?
[quote user="al"]
Ok so what they're doing is like playing each point on the sample phase twice to halve the pitch. Like stretching the sample. </P>
[/quote]</P>
That depends on the method for sample playback. I know of two methods. One is with a fixed clock. In this method, the playback clock is at a fixed frequency and the samples are interpolated to play different pitches.</P>
The second method is to shift the frequency of the playback clock to match the change in pitch of the sample. If there are individual samples for each note, then the first method will work fine without introducing artifacts. However, if one sample is used for several notes, interpolating can introduce unpleasant phase distortion and other artifacts, depending on the quality of the interpolation.</P>
An example of these two can be heard with two old samplers from the 1980s. The Ensoniq Mirage used the first method. It sounded awful. The Kurzweil K250 used the second method. It was more expensive but it sounded much better.</P>
Bill</P>
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Re: What is "Chromatic Whistling"?
[quote user="Orgrinder010"]The only way I can figure, is they have every sample loaded in sync from the get-go. How they oscillate in sync? Maybe like a hammond organ; additive systhesis? I can see if the sound is being synthesized, this would be a simple LFO patch, but using samples... Its not very obvious. Honestly, I have been trying to figure this out myself. I have a soundfont (from a Barton) that has a few tremolo tibias and vox humanas that are in sync, but I don't know how it works.[/quote]</P>
The software would have to be sophisticated enough to keep each tremmed sample in sync. The software would have to be able to recognize where in the trem cycle each sample is to align them properly. It can be done.</P>
Bill</P>Comment
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Re: What is "Chromatic Whistling"? Tremmed Samples
We know tremmed samples can be played. I am trying to understand how. For the tremmed sample there has to be a second channel with trem phase information. In the sampler you have a trem clock running continuously generating trem phase reference. When a note is played the sample starts at the phase point where the sample trem phase equals the reference phase. This way each note will begin at the respective point on the trem phase and all notes will be at the same trem phase. The sample will not be delayed, it will start maybe at the middle of the sample, whereever it is in phase with the reference. Ok, now how do we addon and off samples? So we need 3 samples each with 2 channels - Ch1 with sample and Ch2 with trem reference. This means we need to be able to start the sample playback at any point. I dont know how you handle really long samples. Does this sound right?Comment
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