Synthpopalooza Posted July 9, 2020 Author Share Posted July 9, 2020 (edited) I am currently experimenting with the hi pass filter. These settings: AUDCTL=$64 (1.79 on first and third channel, hi pass filter on first and third channels. AUDC0=$2X AUDC2=$00 This setting uses first and third channels, and can make warbling distorted guitars which go into the 7th octave before tuning errors become apparent. Note table soon ... 65,536 frequencies is a lot to listen to. Edited July 9, 2020 by Synthpopalooza 2 Quote Link to comment Share on other sites More sharing options...
Synthpopalooza Posted July 10, 2020 Author Share Posted July 10, 2020 As another teaser ... This mode differs from the reverse 16 $4x and $8x 9-bit poly, in that you don't get the control over vibrato like you do in those modes, or the C1 range. ... but the tradeoff is you can get up to near C7 without tuning errors here. The $4x and $8x modes only allow about C5 before tuning errors happen, and notes start getting dropped from the table. I can see some Yamaha YM style guitars happening with this one. Quote Link to comment Share on other sites More sharing options...
Synthpopalooza Posted August 5, 2020 Author Share Posted August 5, 2020 New discovery ... When using two tone mode ... sometimes playing the second frequency carrier channel instead of silencing it, makes for interesting effects. Example 1: Zanac Area 1/Area 3 theme AUDCTL=$00 (No special settings) SKCTL=$8B (Two tone mode) 0 - $Ax (two tone modulation channel) 1 - $Ax (frequency carrier) 2 - $Cx (mod 3 aka RMT C bass) 3 - $Ax (standard square wave - arpeggio) When you play the second channel instead of silencing it, it transposes the melody down an octave and changes the wave into a sort of 25% duty cycle pulse wave. Example 2: Donkey Kong Country Stickerbrush Symphony AUDCTL=$60 (1.79 mhz on 0 and 2) SKCTL=$8B (Two tone mode) 0 - $4x (two tone modulation channel) 1 - $Cx (frequency carrier) 2 - $Cx (1.79 mhz - high accompaniment) 3 - $Ax (standard square wave - riff) In this case, $Cx plays the same frequency as $4x, the mod 3 bass notes, but it makes the distorted guitar modulations sound thicker. dkc-briarpatch.asm dkc-briarpatch.s dkc-briarpatch.xex zanac2.asm zanac2.s zanac2.xex 1 Quote Link to comment Share on other sites More sharing options...
Synthpopalooza Posted January 16, 2021 Author Share Posted January 16, 2021 Double POKEY experiments! I have been doing up music from the NES game Metroid. These use double POKEY but are designed to play in mono. First off: Brinstar theme. Setup: POKEY1: AUDCTL=$78 (double 16-bit plus 1.79 clock) 0 and 1: $Cx 16-bit non mod 3 aka RMT E 2 and 3: $Cx 16-bit non mod 3 aka RMT E POKEY2: AUDCTL=$50 (16-Bit on first 2 channels) 4 and 5: $Ax 16-bit bass 6: $8x noise percussion 7: free for game sfx When used like this, double POKEY gives a good rendition of NES tunes that use duty cycle pulse waves. The $Cx distortions stand in, and with 16-bit I can play high frequencies without tuning problems. metroid-brinstar-dblpokey.zip 4 Quote Link to comment Share on other sites More sharing options...
Synthpopalooza Posted January 16, 2021 Author Share Posted January 16, 2021 Second: Norfair theme POKEY1: AUDCTL=$78 0 and 1: $Cx mod 3 aka RMT C 2 and 3: same POKEY2: AUDCTL=$50 4 and 5: $Ax 16-bit bass 6: $8x perc 7: free for game sfx The $Cx channels again do the NES duty cycle waves. As they are mod 3, the tones aren't stable. Does anyone have any ideas on my RESETPOLY routine that can help? metroid-norfair-dblpokey.zip 3 Quote Link to comment Share on other sites More sharing options...
Synthpopalooza Posted January 16, 2021 Author Share Posted January 16, 2021 Last: Krayt lair POKEY1: AUDCTL=$7C (double 16-bit @1.79 plus hi pass) All 4 channels: $Ax 16-bit, plus hi pass modulation POKEY2: AUDCTL=$50 4 and 5: $Ax 16-bit 6: $Ax 8-bit standard square 7: same as 6 but delayed and lower in volume This has a nice swirling lead. I burned all 4 channels in POKEY1, made a megachannel where the 16-bit frequency in the first two, is modulated by another 16-bit frequency in the last two! metroid-krayt-dblpokey.zip 4 Quote Link to comment Share on other sites More sharing options...
ivop Posted January 16, 2021 Share Posted January 16, 2021 (edited) I love the stable 16-bit dist C! Also, the linked 16-bit channels into one big 32-bit channel sounds great, too! Now, CTRL-ALT-1, 2, 3 and 4 (un)mute the first pokey channels in Altirra, but how do I (un)mute the second the pokey's channels? CTRL-ALT-5,6,7 and 8, does not work ? Edit: The Kraid Hideout song is amazing. It even sounds good on the sub-par atari800 Pokey emulation And it sounds so unlike regular Pokey. Possibly even better than the NES original, because it is way crispier Edited January 16, 2021 by ivop 1 Quote Link to comment Share on other sites More sharing options...
Mathy Posted January 17, 2021 Share Posted January 17, 2021 Hello guys This might be a stupid question, but how do I play these sound files? Sincerely Mathy Quote Link to comment Share on other sites More sharing options...
Synthpopalooza Posted January 17, 2021 Author Share Posted January 17, 2021 The .obx loads into Altirra and is an executable. Enable stereo POKEY, and if possible, feed the output into a mixer to get mono, if playing on real hardware. Quote Link to comment Share on other sites More sharing options...
Synthpopalooza Posted January 17, 2021 Author Share Posted January 17, 2021 oh, one trick I used on Krayt: I played a zero frequency for a tick in the modulation channel, everytime I needed to reset the duty cycle and control the swirling effect. That re-syncs the oscillators. Quote Link to comment Share on other sites More sharing options...
Mathy Posted January 17, 2021 Share Posted January 17, 2021 Hello Synthpopalooza 1 minute ago, Synthpopalooza said: The .obx loads into Altirra and is an executable. Thanks, that was the information I needed. I renamed it to .xex. Now Atari800MacX will load and run them. Sincerely Mathy Quote Link to comment Share on other sites More sharing options...
Synthpopalooza Posted January 17, 2021 Author Share Posted January 17, 2021 How is the POKEY emulation on Atari800MacX? Just curious Quote Link to comment Share on other sites More sharing options...
ivop Posted January 17, 2021 Share Posted January 17, 2021 27 minutes ago, Synthpopalooza said: How is the POKEY emulation on Atari800MacX? Just curious It's the Mac version of atari800 with its own GUI. Pokey emulation is similar to atari800 on Linux. Or Windows. Or an Atari Falcon Quote Link to comment Share on other sites More sharing options...
Synthpopalooza Posted January 17, 2021 Author Share Posted January 17, 2021 Cool. Will download it to try. Quote Link to comment Share on other sites More sharing options...
emkay Posted January 17, 2021 Share Posted January 17, 2021 13 hours ago, ivop said: Edit: The Kraid Hideout song is amazing. It even sounds good on the sub-par atari800 Pokey emulation And it sounds so unlike regular Pokey. Possibly even better than the NES original, because it is way crispier That Krayt tune is really interesting. Is it possible to get a 3 or 4 channel rendition to check how a real setup could do? Quote Link to comment Share on other sites More sharing options...
Synthpopalooza Posted January 17, 2021 Author Share Posted January 17, 2021 Will do tonight. Quote Link to comment Share on other sites More sharing options...
Synthpopalooza Posted January 17, 2021 Author Share Posted January 17, 2021 Also: The 32-bit mode will also do swirls on distortion C, and I believe that if you use it on 2, 4, and 8 poly 9, you can get some very finely tuned distorted guitars. 1 Quote Link to comment Share on other sites More sharing options...
Synthpopalooza Posted January 17, 2021 Author Share Posted January 17, 2021 Also next up: Double SKCTL. Seeing what can be accomplished by setting two tone mode on both POKEYs. The opening Metroid theme and also the interlude music are good candidates for this ... 1 Quote Link to comment Share on other sites More sharing options...
Synthpopalooza Posted January 17, 2021 Author Share Posted January 17, 2021 I've also been suggested to try 24-bit: one 8-bit channel modulated by a 16-bit one. It might get another channel free in the first POKEY. 3 Quote Link to comment Share on other sites More sharing options...
Synthpopalooza Posted February 18, 2021 Author Share Posted February 18, 2021 (edited) So, more single POKEY experiments: I finally have a 98% documented note table for AUDCTL=$64 $2x distortion hi-pass with double 1.79 clock. AUDC0=$2x AUDC2=$00 AUDCTL=$64 v1.0.txt Here's how it works ... The first channel is the frequency carrier, and it takes values from my standard $2x @1.79mhz frequency table. The third channel is the modulation. Certain values will make a swirling guitar effect, while others make unpleasant noise. If (freq+4) mod 31=1 on the third channnel frequency, a solid tone is created. As this value goes down, the volume shifts down. This can be used to introduce echo effects into the music. If frequency in 3 = frequency in 0, a solid tone is also made. This is a very incomplete table. Other solid frequencies can be had. Anything with a * after it is the optimum swirling frequency for that note. Also included here is a sample piece: The Area 1 theme from an upcoming 7800 game called E.X.O. This is an original composition. Second channel is a $Cx bass while the fourth is a standard $Ax square wave, The table is very rough, and may have errors. Use at your own risk. exo-area1.s exo-area1.xex exo-area1.asm Edited February 18, 2021 by Synthpopalooza 3 1 Quote Link to comment Share on other sites More sharing options...
Synthpopalooza Posted February 18, 2021 Author Share Posted February 18, 2021 (edited) And then ... the E.X.O. title music: AUDCTL=$40 (1.79 mhz) SKCTL=$8B (two tone) 0 - $Ax frequency modulation 1 - $Ax - frequency carrier, lower volume 2 - $Cx bass (both RMT C and E) 3 - $Ax standard square wave In SKCTL two-tone 1.79, you get two note tables. One is the famous "Save to cassette" bell sound, and one is a higher pitched saw wave. By varying the frequency in channel 1, a volume slide/modulation effect can be had. This mode requires the standard 64khz clock, so you are forced to use standard $Cx for bass sounds and standard $Ax for any other musical tones. This is the title music for E.X.O., another original composition. The volume fade effect is used at the beginning, then the CSAVE bell comes in during the second part. Note table for this setting is available in my POKEY table on the 7800 Programming forum. exo-title.asm exo-title.s exo-title.xex Edited February 18, 2021 by Synthpopalooza 2 1 Quote Link to comment Share on other sites More sharing options...
Synthpopalooza Posted February 18, 2021 Author Share Posted February 18, 2021 On the above setting: I am going to attempt the famous Metroid title music in double POKEY, using the above SKCTL setting, which is perfect for those high pitched notes at the beginning. 2 Quote Link to comment Share on other sites More sharing options...
Synthpopalooza Posted February 23, 2021 Author Share Posted February 23, 2021 A short preview of Area 5 ice world theme from E.X.O. AUDCTL =$61 SKCTL=$8B 0 - $Ax saw wave modulation 1 - silent, frequency carrier 2 - $2x bell @1.79 3 - $Ax bass @15khz This is SKCTL two tone mode 1.79 + 15 khz. You get a nice high saw wave to use atop a deep $Ax square bass. Certain frequencies decrease the volume, I used this to put a delay echo effect in. Binary coming soon. exo-area5.wav 7 Quote Link to comment Share on other sites More sharing options...
Synthpopalooza Posted February 27, 2021 Author Share Posted February 27, 2021 Final .xex for E.X.O. Area 5. Enjoy I will do a stereo version next exo-area5.asm exo-area5.s exo-area5.xex 6 Quote Link to comment Share on other sites More sharing options...
emkay Posted March 1, 2021 Share Posted March 1, 2021 On 2/23/2021 at 6:34 PM, Synthpopalooza said: exo-area5.wav 5.18 MB · 22 downloads How is this recorded? Quote Link to comment Share on other sites More sharing options...
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