Subject: Re: [linux-audio-dev] [ann] unmatched - a LADSPA amp tone
From: Tim Goetze (tim_AT_quitte.de)
Date: Sat Oct 26 2002 - 01:47:53 EEST
Steve Harris wrote:
>On Fri, Oct 25, 2002 at 10:15:20 +0200, Tim Goetze wrote:
>> >Nope, that would be hard ;) I was thinking of having a second, hard
>> >clipping alg. and bringing that in for high ampltudes.
>>
>> oh yes, please keep on bringing them on.
>
>OK, I have some pending (easy) improvements to the meters, then I'l get
>onto this.
:)
>> i put in a music-dsp shaper (archive credits patrice tarrabia
>> and bram) after the inverter, and with some eq (hp basically)
>> before entering the first valve, it sounds surprisingly good.
>> especially with the bridge pickup, the neck pickup is still a
>> bit muddy.
>
>OK, time for a quick lesson - whats the difference between the pickups? My
>bass (cheapish active 4 string) has two sets, a single wide one and a pair
>slightly offset (they say duncan on them FWIW). There is a knob that, I
>think crossfades between them.
the neck, usually placed exactly where the second octave is on
an over-sized fretboard, has far less dominant harmonics than
the bridge. your bass probably is a fender 'precision' type.
usually the split pickup is in the 'neck' position, though it
is much closer to the bridge than on a guitar, because the
sound becomes too dull if you pick up too little harmonics i
guess.
>> * it doesn't noticeably prolong sustain.
>> * the attack phase is 'flat', compared to the ringing
>> of the real thing.
>
>OK... could this be a property of the cliping? Or is it always there?
always. i think it might be because a real valve amp sort of
'spreads the excess power' by turning the wave into almost
square at this point, where the guitar signal carries a lot of
energy. more of a limiter effect, right?
>> * the sound gets muddy and faint when you turn down the
>> volume at the instrument, instead of keeping loudness and
>> reducing distortion.
>
>This is another compression effect I suspect.
>I think that the compression effect in a guitar amp is much faster than
>what you get from a general purpose compressor. I think it is more like a
>slow acting saturation. My Valve rectifier plugin (valve_rect) was an
my thoughts, too.
>attempt to capture that, but I expect it needs adjusting, or rewriting.
i just tried it before the first valve and it does help a
good deal to have a better attack [in fact i got carried
away strumming a funk pattern, a first time for playing the
guitar through the box], but i'm slowly running out of cpu.
i guess a real HP has to be added, too (the pre-eq is done in
the mixer now) because the lower band still has too much shaping
power over the sound (sort of an auto-wah effect, emphasizing
the 'flat attack' problem).
tim
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