Filter sweeps.

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Listening to 70's recordings etc I've noticed how filter sweeps on original Modular's of the time could produce a really biting and expression filter sweep.
Hard to describe but a round soft tone that sweeps into a cutting treble WiiooooW.
I know that with a standard Vco to Vcf you cannot get this sound on early Modular's ....there has to be some "extra" module or technique used..
Has anyone any idea ?

[analogmonster]

Can you provide a sound example or a link to a sound example?

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Hello...not sure how to add an audio sample here....

But think of Jimi Hendrix Wah pedal where it really bites and " talks"and imagine that a lot slower and brassy.

I've tried incorporating the Fixed Filter bank in the signal and that does help a great deal as does a High Pass filter and everything "tuned" such as release down to virtually zero on the VCF EG control. This has quite an effect on the sweep.

I know chasing a sound from the 70' s is usually a fruitless task due to old recording techniques etc.

But when ever trying to emulate say orchestral trumpets or trombones with a long sweep, I always feel there's something missing in my attempts as if the filter or the EG's were not firing on all cylinders. I'm always in conflict about the use of resonance here with brass. You do get more of a pronounced sweep with resonance but you corrupt the pure brass timbre.

I just wondered if there's some known technique to produce that long extra biting brassy sweep where the filter really opens up.

[analogmonster]

Hello...not sure how to add an audio sample here....

If you find a YouTube video with a good example you can drop the YouTube - link here together with a rough timing information where the relevant part begins.

...
I've tried incorporating the Fixed Filter bank in the signal and that does help a great deal as does a High Pass filter and everything "tuned" such as release down to virtually zero on the VCF EG control. This has quite an effect on the sweep.

Yes, but even with a Moog 914 or 907 with real inductors the sound gets thinner with that, so using the FFB means the need for additional amplification afterwards.

I know chasing a sound from the 70' s is usually a fruitless task due to old recording techniques etc.

Yes, that's true. The sound result is the sum of the instruments, mixing technology, recording technology and most important the fails, errors, lacks and quality issues of that time. But at the end this creates the atmosphere behind. Even record scratches are sampled sometimes from modern music producers to imitate that time! Perhaps one must become worse to become better

But when ever trying to emulate say orchestral trumpets or trombones with a long sweep, I always feel there's something missing in my attempts as if the filter or the EG's were not firing on all cylinders. I'm always in conflict about the use of resonance here with brass. You do get more of a pronounced sweep with resonance but you corrupt the pure brass timbre.

That is definitely a point. It might be that your EG does not open the VCF or the VCA wide enough. The 911 is not the strongest, which I noticed when I cloned the Moog System 55. <Side remark> I am currently cloning the Oberheim 4-voice and made therefore experiments and experiences with the SEM EG sub module, which is much more snappy and stronger than other EGs, and that is part of the reason for the gorgeous sound of the 4-voice </Side remark> To get horsepower into your brass you definitely need resonance (but carefully dosed!) and strong, snappy and long lasting EGs for VCF and VCA. What is the maximum output voltage of your EG?

I just wondered if there's some known technique to produce that long extra biting brassy sweep where the filter really opens up.

I think you need enough output voltage provided by the EGs, snappy EGs with zero time attack and long DECAY phases first. Concerning the filter I would not use an FFB or high pass filter like the 904-B, as they smooth the sound thinner. If I really want to tease the lines I use the 904-A with moderate resonance in conjunction with a 904-B and a 904-C in band reject mode to emphasis the high and the low parts of the frequency spectrum. For me this is the optimum, so I use this filter patching in most cases to create really fat sounds.

For weak voltages I developed a nice modular helper module, the TAMP amplifier cascade for my Moog System 55 clone, which I use to pimp weak EG voltages or weak audio signals from external sources (see web site). It is easy to build, so I can send you a PCB if you want, or a complete module.

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Thanx A.M. ...this is most appreciated.

Right now I'm going to experiment with the 904 abc as you described. The little pieces of information you shared are like gold dust in my never ending search for certain sounds.

I knew the 907 reduces the audio level and I've never been happy with this. I almost wondered if to incorporate the input and output buffers of the 914 but I don't know if this is worth the effort . But I use the Noise module with LOW and HIGH pass filters and the high pass seems to actually increase the audio level.

I always thought the 911's were powerful enough but I've routed thru a spare CP3 and that does increase the sweep although I've found 2 911's with different settings routed thru a CP3 works well. But I'm still not satisfied. I'm always frustrated when I hear cheap synths that seem to have a biting filter sweep .

I will certainly try brass timbres in the Band Reject mode ..this has given me some inspiration.

Let me look at your Tamp Cascade ..how much would a PCB cost?

Thanx again for your time and all the detailed information ...regards

[analogmonster]

...
I knew the 907 reduces the audio level and I've never been happy with this. I almost wondered if to incorporate the input and output buffers of the 914 but I don't know if this is worth the effort . But I use the Noise module with LOW and HIGH pass filters and the high pass seems to actually increase the audio level.

You could increase the output level of the 907 with the TAMP module as well. The stages are DC coupled, but of course AC / audio material is amplified as well. You would probably need just one stage, but if you would need more you could cascade it up to the desired level easily. If one stage would be too strong for your purpose, you could patch an attenuator in between. The phase inversion should not play a role for audio material, but if it would be a problem you could cascade two stages for double phase inversion with attenuator.
The stages are completely independent from each other, so you could pimp EG and 907 outputs in parallel / the same time.

I always thought the 911's were powerful enough but I've routed thru a spare CP3 and that does increase the sweep although I've found 2 911's with different settings routed thru a CP3 works well. But I'm still not satisfied. I'm always frustrated when I hear cheap synths that seem to have a biting filter sweep .

Another idea I had due to our discussion here is to use an AR envelope which has a kind of trapezoid output for brass, where the maximum voltage after the attack phase is kept by guarantee / for sure due to design, as there is no decay phase / voltage at all, so nothing can decrease here.

I will certainly try brass timbres in the Band Reject mode ..this has given me some inspiration.
Let me look at your Tamp Cascade ..how much would a PCB cost?

Naked PCB: Euro 20.00 plus shipping
Populated and tested board: Euro 110.00 plus shipping
Complete / mounted / tested module incl. connectors and front panel as you can see on my web page: Euro 210.00 plus shipping

Thanx again for your time and all the detailed information ...regards

You are welcome. If there are more questions / points to discuss don't hesitate to ask.

Best regards

Carsten