14 January 2017, 14:16 | #81 | ||
son of 68k
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14 January 2017, 14:27 | #82 | |
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Just because cheap converters perform bad, doesn't mean that 48 kHz can't be good enough. Quantization noise relates to the bit depth of the sampled signal. With 8 bit it is quite audible with most sounds, but with 16 bit you will need to turn the volume up very loud to be able to hear it, and then you will still only be able to hear it during very soft parts of the music, so effectively it is not an issue with most music. In cinemas where you have a large dynamic range, it makes sense to go above than 16 bit. |
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14 January 2017, 15:02 | #83 | |
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I'll go over the main points of this thread;- 1) The examples are not clipped. You cannot clip when transferring a mod to a Wav with Sonique. You CAN clip if you over compress, unless you tell the digital compressor software not to. 2) The reason for the digital delay is the way that the human mind interprets audio. If a sound has out of phase left and right elements, played through speakers, people can give it a direction. 3) Neither these examples nor any Prodigy track is truly "distorted". Instead, they have had their decibel levels raised - in this case, to 130 or so. So of course they sound distorted unless you turn your levels down. These examples and Prodigy's run the razor's edge. One more step either way, they would be losing fidelity. Instead, they soak up and use all the available bandwidth. That's why they are "Always outnumbered. Never outgunned." It's also possibly why they don't bother about arguing that their works are clipped and distorted. They know that they aren't, and if other people mistakenly think that, then it's somebody else's mistake, not theirs. The difference between the Prodigy and myself is - I'm not trying to sell a record. I'm not trying to promote an album, do a tour, arrange a gig, or even sell a T-shirt. I'm saying this is how you can make original Amiga audio sound - meaty, dynamic, powerful, and attractive to 21st century ears. If somebody else wants to do this, design, build, test and sell hardware, fine. I can't claim Intellectual Property over maths. I certainly can't claim IP over a work based on a Public Domain release (unlike Akira, who seems to think that's legit). |
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14 January 2017, 20:42 | #84 | |
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If I have to turn my equipment down to hear your music correctly then you're doing it wrong. |
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14 January 2017, 20:55 | #85 | |
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Prodigy uses distortion to a large degree, like many others as a musical tool. As Daedalus writes, this has nothing to do with the volume you play back at unless you have really bad speakers. If the distortion changes with volume, your system is non-linear and this is bad. Of course any speaker will distort when it becomes loud enough, but it should not happen within normal listening levels. When you write '130 or so', what do you mean? Decibel? Because Decibel is not a unit, it only tells on a log scale how large something is relative to something else.. On a digital signal, 0 dBFS is full scale and you cannot go any higher. Most music will have a level of between -20 to -10 dBFS RMS. The higher, the more compressed it generally is. Listen to this track and tell me it is not distorted: [ Show youtube player ] They distorted several of the instruments on purpose and it sounds great. It is one of my favorite Prodigy tracks. |
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14 January 2017, 21:14 | #86 |
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Just use whatever sounds good and be done with it
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15 January 2017, 05:10 | #87 |
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Really? I was always under the impression that NTSC allowed a slightly higher sample rate than PAL, having something to do with the screen refresh rate (although I know this is not the same thing as horizontal refresh rate which allows 56KHz under certain screenmodes), at least in the table of notes the rates are slightly higher under NTSC than PAL. Can someone clear this up?
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15 January 2017, 09:08 | #88 | |
son of 68k
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IIRC frequency limit is 28604 for PAL, 28867 for NTSC (period 124 in both cases). |
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15 January 2017, 11:22 | #89 |
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Cool, thanks for that. I have another question about Paula when playing the two uppermost notes in ProTracker, which are both above the maximum frequency range of the Paula. For those of you who don't know, they play ok, but with glitches, presumably from skipping the odd bit of data.
Is playing samples at rates higher than the Paula can actually output a feature of the Paula, or is there some kind of coding trick used in module replayers to allow these notes? |
15 January 2017, 11:27 | #90 |
son of 68k
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They play with occasionnal glitches in most module replayers, too. The only way to play them safe is by some kind of downsampling.
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15 January 2017, 11:33 | #91 |
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So does that mean module players and trackers DO do some coding tricks to prevent some kind of crash which would occur if one were to attempt to feed an illegal value to Paula?
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15 January 2017, 11:35 | #92 |
son of 68k
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No, they really feed illegal values to Paula. No crash can occur from this, Paula will just eventually output bogus sounds.
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15 January 2017, 11:41 | #93 | |
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The limit is in how quickly the DMA system can feed fresh data to Paula. The DMA system is in sync with the video display, and only one word of data per channel can be fetched per scanline. That's why the maximum sample rate varies slightly between PAL and NTSC systems. It's also why with 31KHz video modes those glitches disappear - because the audio DMA slots are now roughly twice as frequent. |
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15 January 2017, 19:58 | #94 |
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15 January 2017, 20:30 | #95 |
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I wouldn't be surprised if there's a DMA limit. I've tried 56khz using Hippo Player, and there were glitches. With the CPU the limit is much higher, and perhaps the Copper can do it too.
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15 January 2017, 21:09 | #96 |
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"AddAudioModes dblscan" from AHI packet should do the trick.
Code:
The DBLSCANoption does not have anything to do with the audio mode list. If specified, it will open and then immediately close a native, double-scan screen. On some systems using a graphic card, this will enable >28 kHz sample frequencies with the native audio. You need an appropriate monitor driver in DEVS:Monitorsto make it work. |
16 January 2017, 02:02 | #97 | |
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CBM didn't ever write that part of the HRM of course, Hi-Toro/Amiga Inc did. I have not checked the later HRM edition, so it could be a typo, or perhaps CBM just didn't like the idea of their American customers having a slightly suspect sample rate. It might explain Akira's claim that the released version is different in pitch to the original. Not sure about that, have no idea what tools they used or their source of the audio, but in terms of playback on a PAL system it is a match, for frequency response. As Sonique is French, with a SECAM background, the writer probably took account of the different playback rates and adjusted accordingly. That's my guess, perhaps it only works with PAL sourced mods after all. I think I muddied the waters when I said that Paula was limited. Other posters are more accurate here, it is the DMA via chip RAM that causes the limits, and while you could use the CPU to write a custom copper list for the next vertical blank so that the copper writes the values into the audio DACs on time, it would probably be very glitchy unless you got it absolutely perfect every time. That's on the Amiga, of course. Amiga 8 bit Sampling software capable of capturing audio at that rate shut down all activity while sampling, and started up again when the user had clicked a mouse button or similar to indicate the sample recording be stopped and the system returned to "normal" again. Last edited by Pat the Cat; 16 January 2017 at 02:32. |
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16 January 2017, 02:08 | #98 | |
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This is a technology demonstrator for developers to study, in terms of what happens if you use purely digital, software techniques on Amiga sound data. With the desired goal of a hardware add on to enhance Amiga audio. If I thought I could do that on my own, with a completely designed solution, controls, limiters, filters etc etc I would have just done it on my own. it would have saved an awful lot of goalkeeping. Last edited by Pat the Cat; 16 January 2017 at 02:18. |
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16 January 2017, 04:09 | #99 |
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16 January 2017, 04:31 | #100 |
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Been a long time since I played one... IIRC correctly, there are minimum requirements for playing fast samples. Accelerator and fast RAM, if you want to do so from Workbench. You can do so on any Amiga technically, but you can't do much else at the same time, on a chip RAM only / 68K machine.
Take this with a pinch of salt, I only played very briefly with an early version of Hippo. a long long time ago. |
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