emusonacid! legacy

tonight i decided to take my existing test tones and creat copies of them so that they would start negatively. so now i have copies that go positively and negatively. i spent, and i kid you not, an hour on just getting the triangle wave to sound right. typically when you set the loop point wrong on a wave, you will hear the pitch climb every loop when you play it in reference to a stable looped wave. providing you can figure out what wave is the one that is out of tune, so to speak.

all the other waves had gone well. all looped proper and sound good. then i had this idea. if you check the fix box in the loop section you can move both end and start together. so they stay the same distance, but move about the length of the sample. so my idea was, perhaps i could control the loop points with the destination "sloop".

well i loaded a sample from a led zepplin choon and looped it. i hit the key and started to play around with the mod wheel, seeing if it would do anything. nothing was happening until the restart of the loop. all the sudden i heard this click and i had the left channel play as normal and the right channel out of sync. so i tried it with a mono sample and when the loop restarted, it just clicked and started the loop a little bit in to the sample. I tried this with an lfo moding the sloop, and all it did was act like the mod wheel cord.

so, my question is: does anyone know what the point of this cord is? why do we have the sloop thing and how do you us it proper? as it stands this is a completely stupid cord. i see no value in it what so ever. but like i said, perhaps i am not using it proper. anyway... does anyone have any ideas on how to us it proper? any one used it for something? am i missing something?

cheers

i think it has more use for very short or even single cycle waveforms
i was disappointed when i realised you couldnt make it work with loops, but you can make some good sounding stuff on the afformentioned short waves
hope this helps

well, that sounds exciting. i guess. yeah it was a real bummer that it just, i guess, loops the first little bit, i guess. i think i will play around with using a small single wave loop or something and see if it does anything extremely cool. so far i am not impressed all that much

thanks for the response, i am glad to know that i am not the only person to be disappointed by that destination cord....

oh well.

Hi there! :O)

I've been playin' about with the Sloop destination for quite some time now, and I've come to the simple conclusion, that it works simply by offsetting the entire loop with sample accuracy. This means, that at full modulation of the Sloop cord, your have actually offset the loop 128 samples. What can we use this for?... well one VERY interresting use is to prepare some special single-cycle waveforms that are capable of some interresting effects. One worth mentioning is the Pulse-Width-Modulation wavform! I've tried it out, and it works fine! ... Yes! you can do realtime PWM on the E4 :O) ... I've simply created a waveform that do PWM by sweeping the Sloop cord... This way you might think that the biggest single-cycle waveform could then be 128 samples long? ... no, it can be 512 samples long if you just use the Gain4X on the modulation source. It takes a little experimenting to get the loop and waveform right, but it's worth quite a lot i think!... I just wish it was possible to offset the loop in larger quantities than just single samples. Imagine if you could offset in 256 sample chunks instead!? that would allow for some kind of limited wavetable synthesis!... DID YOU READ THIS EMU!? ;O)

So you're saying if I sweep sloop on a square wav I'll have a pulse wave?

It seems to me as though it wouldn't sound too good w/ any other waveform type, as it would cause clicks... interesting idea though. And you're right, if it had higher granularity you could do things similar to what you can do on many wavetable synths. But if you think about it, the E-Mu is already doing enough to strictly qualify as wavetable synthesis... just without some of the cooler morphing features (although I'm wondering if it would be possible to do some of that w/ sample crossfading/etc)

Both yes and no! ... It depends on how the squarewave looks. If you imagine a square waveform that is looped (one cycle only!), and the sample data emidiately after the loop end is just a continuous "straight line" with the value the looped portions last sample had (which is normally max negative value), then when you change the loop position up to about halfway through the first cycle, it will work as a pulsewidth modulation, gradually narrowing the PW. It's kind of hard to describe... but I assure you, that it sound just as good as any real synthesizer!

but, wouldn't that cause the tone of the sound wave to change pitch though? i mean as you shorten the loop, the pitch of the wave would go up, or am i missing this...

No, because the sloop cord does not just change the start or end point, it actually change both of them equal at the same time, so therefore, the loop length stays the same. It's simply the whole loop section that is offset! :O)

That's a great idea, razmo I tried it out last night, and it worked perfectly. It only took me about 2 minutes to whip up the wave in Sound Forge, then sent it to the Emu, set up the cords and end up with perfect PWM! I'm gonna have to tweak with cycle lengths, cord settings, etc to get my modulation exactly the way I want it, but it works great so far.

I'd tried to emulate PWM in the past by sampling pulse waves at different pulse widths and using the RT window to modulate through them, but it never sounded right, since you'd either hear bad 'stepping' , or hear two samples with different pulse-widths playing at the same time. That actually sounded cool, but not like PWM.

Well, I'm glad to be of help! :O)
Any trick to make the sampler able to sound a bit more "real synthy" i a welcome thing with me!

okay, i must be tired, had issues last night with my cd burner... never, ever again will i ever use rca plugs. straight tsr and xlr for this kid...

anyways.

so you are saying that if i have a square wave looping a single cycle, say at 440 hz (approx. 50 samples for positive, 50 samples negative, disregarding the attack and decay of said wave) i can set up that cord, and adjust the start and end points with in that sample and it will not change pitch? this is where i get confused, it would seem that if there is not were for the end section of the loop to go, then it would just make the sample lenght get shorter, or not move at all.

but if i select a wave that has say a one cycle loop, but has two cycles going, then the sample should sound the same regardless of what i do with the sloop. i have found that you can loop a single cycle anywere in the wave it self, it doesn't change the sound at all. what i mean is, you can start in the middle of the positive part of a square wave and end at the pos, it will be the same.

maybe i am over thinking this. i will try it out tonight and see if i can get it two work. this actualy gives me an idea for something. and i will try that as well.

this is going to be cool and really do things for me in my sound design.

cheers razmo..

Hi again! :O)

You are absolutely right that the sound will not change if you have a series of identical squarewaves, but as I said earlier, if you take 2 squarewave cycles in succession and ONLY loop the first one, you would have one more square cycle AFTER the loop left over to sweep into. This extra "space" ensures that the sloop cord can actually offset anything, otherwise the loop would not be able to be offset further "back" in the waveform. Now if you sweep the sloop cord in that configuration you'd NOT be able to hear anything but a squarewave because, as you said, it will always be a perfectly looped squarewave, but here is the trick: erase the whole last cycle with max negative values and then try sweeping again!!! ... see? :O) ... perfect PWM for you! ... just mind that the sampler need a bit of samples at the start of the waveform before the loop start. I've had nothing but trouble with precise looping if this is not done (I find that the zooming util of the sampler itself is very inacurrate at high zoom ratios, and this has never been fixed). Also note, that the sampler is interpolating, and therefore use some samples for this in exess of what one would normally think (that's the reason why you have to leave at least 4 samples intact after a loop to avoid clicks and so). The interpolating should logically result in some errors in the PWM trick, though I've not tested this yet.

okay, so basically for this to work, you need to have a cycle and a half. is that correct. i think i am going to play around with this a little night or tomorrow. i am a bit tired, i just finished a tune and i have had nothing but late nights. i guess i need to do one more eq adjustment and i will be containt with it. man, i am tired.

this is a cool trick though...

Yes that's right. There is no need for more than half an extra cycle when it's PWM you're after. With other specialized waveforms it might be appropriate with a full cycle more though. By the way, if I recall right, I believe that EMU also made such sloop-sweeping waveforms in their "sounddesigner's toolbox" bank.

i got it to work the other night. but the strange thing is when i apply the mod wheel, i find that about in mid stroke of the cc the tone seems to go back to normal. then it starts to pwd again. is that normal, or am i still setting it up off?

i have some good ideas for this now. pwd between a sine wave and a saw, wil have to see if that works. i wonder what off stuff that can be done too.