A4 deep bass tips?

It took me a week to accept the A4 as an instrument with its own character. I may not get the OSC behaviour that I am used to, but then I have some VSTs that cover that.

What did help me was the fact that the A4 can be used as a monosynth with up to 4 layered but independent voices. Whenever I need more power in bass, I can layer a second voice, either a subby triangle or a detuned copy of the original sound, or a neighbor track with a resonant high pass. There are plenty of options to create deep bass when you go beyond one voice.

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^Yea!
Unison use track sounds is massif!!!

I agree with all of you. It’s possible to get perfect waves with other gear. Anyway, Analog 4 would be better if it could respect input waves thru the filters before tweaking. I miss the “normal” option. And about HiPass res to get more bass…that could be even better. Other HiPass filter do that job in a more accurate way. I would prefer a HiPass filter that doesn’t filter any low frequency if it is set to its minimum level (other HiPass filter have the same “problem”).
I kept the Analog 4 for all the valuables functions in despite of several weaknesses. I was very disappointed at the beginning, because I thought I could get Prophet 6 pure sounds. At the same time I had a lot of pleasure with mangling ability, or even sweet sounds. I love to use it with 0 Coast. It controls 4 CV, and adds overdrive, AM, feedback, filters… very funny. I also love the fact overdrive is part of each voice sound path. It’s the only analog polyphonic synth I know that has dual filter with overdrive and feedback per voice… It’s wonderful to make strange organs for example. That inspired me new Nord G2 patches. Sure, they don’t sound exactly the same in the Virtual Analog way… but that’s also interesting. Everything leads to use G2 :slight_smile:

maybe try a keytracked peak filter then

In what way more accurate ?

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thankyou very much for this!

Have a look here fwiw

I hadn’t seen any of the tail end of this interesting thread when I posted just above here, there’s lots to ponder


One thing that has popped up here again is the lack of key track as a modulation source, it could be handy for adjusting the pulsewidth of all shapes to achieve consistency or otherwise amongst many other things

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Okay - I was somewhat curious, i needed to satisfy myself that some of @guiltyrollmops’s findings were the same here, so i set up a little test

I’ll present the findings in a similar manner, this is not necessarily the full story, but it’s certainly a fascinating insight into the character of the A4 filter, and crucially a lesson into how to set it to be ‘neutral’-ish

Please note, this was looked at with no key tracking, normal default res ‘boost’ and for an audition/viewing friendly frequency 65Hz-ish

I fed the A4 a Nord Modular G1 signal with three different shapes for info, having been amazed by the influence of the filter (and variations) on the square - for the square there is a recommended ‘flat’ filter setting (25 res on LPF ) and a value which gives better visual correlation (a pulse width varied shape was thrown in as it wasn’t always easy to see where the duty cycle of the post filter square was) for the saw and tri i have added in a zero res setting to show just how much the filter will impact the waveform, so they’re both shown at 0,25,64 (where 64 gives a closer approximate visual representation of that wave at that frequency) (Note no filter key tracking)

Two identical signals were sent into the A4, one direct via Ext In roughly level matched to a signal pulled clean through the Oscillator Injection of Osc 1 (so the A4 oscillators are all off) with max amp level (ext in level lower)

Both pulled through OB/Live to a pair of waveform monitors running simultaneously on Left and Right respectively, that way you can view the source and the impact on the source in real time

Note this doesn’t tell the whole story and it may be a flawed analysis, but it’s an interesting insight nonetheless - those high res settings may colour the sound somewhat, especially in other frequencies, so this is a partial insight into a complex picture

The filters are certainly not transparent, it does indeed beg the question, could they be bypassed for an extra flavour of sound, it’d be interesting to see what shape the A4 sends out pre filter, i bet they are more ‘regular’ looking than we all assumed

I’m glad i caught this part of the discussion above, i missed most of it since it got revisited a week or so ago, interesting … i didn’t try with resonance boost off fwiw, but it’s clear that the filter pair are a big player in the overall sound

It’s fascinating to see the impact of varying the peak filter full range, it inverts the signal when you go from freqmin/res0 to freqmax/res0

Anyway - for all the figures, they are presented as a snapshot of the filter settings and the A4 inject via filter is the upper waveform, the lower waveform is the direct one via Ext in - both are sent through main output via OB (i was monitoring pre OB) - not sure if i should have been doing anything about the DC offset

It would have been better to include a spectroscope


Nord square

:elan: res 25

:elan: res 25 (reduced pulse width)

:elan: res 70 !


Nord saw

:elan: res 0

:elan: res 25

:elan: res 64


Nord tri

:elan: res 0

:elan: res 25

:elan: res 64

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I meant… A HiPass that only filters under cutoff frequency.
You:re right. Peak filter can be useful.

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Very interesting!
Res 65 usually looks better, no?

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It gets closer visually (at those osc settings), very strange, but it was an interesting learning exercise

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In the interest of fairness, i noted that the input level can also make quite a big difference, there’s a threshold after which the input level will not be matched 1:1 by a throughput level but the shape will distort as the disparity between levels gets more noticeable, even on a sine wave … it can be very accurate up to a certain point and the level is increasingly constrained, but the shape will change

So I ran these in Max to overlay them, but with a reduced input level to the filter stage (reso boost was off, but it seems to make no difference to the shape at these input/filter settings anyway) … i tried to match the energy at the nominally flat resonance 25 setting so that a tri/saw were roughly level, then left all settings and levels alone, except for resonance and i varied the shapes, this time presented showing the influence of resonance on the apparent transparency of the filter block, it gets more analogous with higher resonance at these osc/filter settings, but it may be problematic at other frequencies

attached for completeness - square is still suffering the most visually, there is some phase shifting due to the odd post-filter waveform and the detection algorithm struggles to find the rising edge

seeing this has not changed my view of how to use the machine, i still use my ears, but if you’re striving for a certain sound, it may be good to appreciate some of these nuances … resonance really plays a big part in this

So, sin/tri/saw/square Nord shapes (only varying the A4 redo, nothing else) (all else as per post above, including caveats) Note : no A4 oscillators

In all shapes, the increasing resonance is possibly having the effect of reducing the energy levels (away from the resonant freq) though it’s harder to read for the saw/sqr

Nord Sin

various resonances





Nord Triangle

various resonances





Nord Saw

various resonances





Nord Square

various resonances





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A thorough and interesting post, @avantronica !

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@avantronica
Very accurate test! Res 64 still seems best setting. Freq is 127? Best square I got was with res 127 I think…

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Yeah, same filter setup as above, LPF127 and PK127res0, just dropped the input level as the A4 responds non linearly to the input and redid

I didn’t go all out to find the best res, but pushing it beyond half way introduces ringing quite quickly

The trouble with very high res is that it makes musical filter modulation complicated, so for me the exercise was more about learning a bit more about how the A4 works … I hadn’t quite expected the results you see when you vary filter parameters, especially on the square

Keep in mind, the AK may be different, although I thought those documented differences were further down the voice path

We’ve also gone a little bit off-topic, but for understandable reasons, this exploratory part of the thread could be split off as a discussion on filter transparency perhaps

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Tried…Overbridge?

wrt the 2 posts of waveform comparisons above, i thought it may add a bit more insight to present white noise, direct through and also through the filter, as per all the settings above … keep in mind the white noise is a moving spectrum, the relative levels fall and rise, but you can read the average to get a ballpark feel for what’s going on, it does seem that res 25 (as :3lektron: recommend) is about the closest over the full range, but to get the lower frequency levels heading towards the same as the source (relative to most of spectrum) the greater resonance boost does the trick (at the expense of the peak in the upper range)

whichever way you want to look at it, it’s clear the filter has an effect, even at the most neutral settings

as suggested above, it’s like a gentle high pass and also a bit of a low pass roll-off in the highest frequencies

the rest of the info displayed in above posts is not about trying to recover a magical shape for the source wave, but to try to understand what the filter may be doing - the added resonance doesn’t fix things per se

I’m increasingly wondering if the AK and new Mkii A4 are addressing this particular aspect of the filter (or possibly more parts of each voice circuit)

LPF Max Freq (variable res) & Variable FIlter set as Peak, Max Freq, Min Res


white noise source (Nord Modular) via Ext In


:elan: resonance 0


:elan: resonance 25


:elan: resonance 64

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Been meaning to try some of these tips, finally got to it.
Tried Area303’s settings, then murkey’s tips.
I made a few tweaks and came up with this.

OSC1
Tun -12
Lev 80
Wav TRI
Sub OFF
PW 0

FILT
F1 17
Res 0
Ovr +19
Trk 0
Dep 0

F2 31
Res 50
Typ LP2
Trk 30
Dep 0

AMP
Atk 1
Dec 127
Sus 127
Rel 7
Shp 1

ENVF
Match AMP

If you’re like me and you still enjoy that old school sub wobble,
turn the Vibrato speed around 40, and the the VIB to 40-70 range

If you like a long sustained sub bass tweak the amp and flt env.
Turn both SUS to 0, and crank the REL to something like 90

Great thread!

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Hello, you probably forgot to put a Number before the ZERO on the DEP on the filter page. Well I think ?

No depth on any envelopes, just key tracking on FLT2

This thread :+1: