TT 303 - Thin Sound?!

[m:o]

i just got my TT 303 in the mail today.
there`s a massive drop in Volume and low frequency content when turnig up the resonance of the filter. While i know drops of Volume an Lo Freq on other Filterdesings, this here is at a unusable level......

here`s an example
https://soundcloud.com/biloba/303-volume-drop

Anyone of you can confirm this is normal with a tt 303?
so far i use massive compression to compensate for the volume loss..

best
mo

[timday]

I don't know if it's normal for a tt303 but a lot of synths do this including the vintage Moog Prodigy we have at work. What I *think* is happening is that as you boost the resonance with the volume on full or close to it, the volume self adjusts so that the resonance peak doesn't cause clipping in the output stage. Don't forget resonance actually increases the volume of frequencies around the cutoff point to quite a high level, it isn't just a tweak to timbre that is neutral as far as volume goes. If the synth compensates in some way it can give the effect of the filter turning into a band pass at high resonances.

If you want an example of a synth that doesn't do this give a listen to an Arturia MiniBrute - the resonance boost is quite pleasant with the volume at about 50%, but if you crank up both the volume and the resonance it turns into something pretty horrible.

What might work is to keep the output volume at about 50% and compensate with more gain on the input stage of your interface or mixer. It works on a Minibrute in that you then have enough headroom in the output stage that when you boost the resonance the unpleasant edge is gone from the peak. By analogy it might work here depending on how the volume adjustment works. If you try it be sure to give yourself a decent amount of headroom in the recording input at low resonance as the volume will (hopefuly) now increase when you turn the resonance up.

Anyway if you're already know this and are doing this doing this I don't know what else to suggest I'm afraid

[paulmaddox]

Sounds like normal behaviour to me - Use compression if you need the level to be more consistent.

[pamplemousse_mk2]

I think that the decrease of the volume is due to the harmonics going out of phase when tweaking the resonance, in a way that they cancel themselves.

Check this page :
http://www.indiana.edu/~emusic/acoustics/phase.htm