[linux-audio-dev] Linux Audio Experiences

Dave Robillard drobilla at connect.carleton.ca
Tue Mar 2 13:35:22 UTC 2004


On Tue, 2004-03-02 at 05:55, Tim Goetze wrote:
> [Dave Robillard]
> >> being the author of plugins intended to fill the gap, i'd love to
> >> hear some constructive criticism. so would you care to elaborate
> >> on what you find lacking in our efforts, please?
> >>
> >> tim
> >
> >Oh, well I didn't mean your plugins are inadequate in any way, but that
> >it's a very complicated problem.  Plus, even if you create one good
> >sounding 'amp'.. that's just one.  One amp is never enough for anybody.
> >:)
> >
> >Anyway, I own a Behringer V-Amp so I havn't really tested your plugins
> >much, but I will if you like.  I've been a serious guitarist for over
> >half my life, so I like to think I have an ear for these sorts of
> >things.
> >
> >Give me a few days, I'll put some comparison tracks down in audio (if
> >necessary)
> 
> writing down your impressions will do just fine, thank you.
> 
> if you'd like to help out with recordings, here's something that we
> will all benefit from:
> 
> you may know that the 'tone' of an amplifier is mostly created by its
> imperfect frequency response. recreating this feature is quite easy
> to do: obtain an impulse response from the system in question and
> convolve a signal we want 'tone-coloured' with the impulse response.
> 
> so, in order to have more choice of 'virtual amps', first and foremost
> we need some impulse responses to model.
> 
> this is where you can help. set your (virtual) amp gear to:
> 
>  * 'clean channel' if there is one
>  * no compression
>  * neutral tone controls
>  * no 'speaker emulation' (connect preamp-out on a real amp)
>  * no effects of any kind (reverb, chorus etc)
> 
> and record an impulse response from its different 'amp electronics'
> settings. this is fairly easy: feed the unit a one-sample impulse of
> full amplitude, followed by silence, and record the output of the
> unit. among other methods, you can create the impulse with steve's
> impulse_1885 plugin.
> 
> after that, turn the virtual 'amp electronics' off, if possible, and
> record impulse responses from the unit's various cabinet/speaker
> emulations in the same fashion.
> 
> -
> 
> if you want to be a real hero of amp modelling, turn off all 'amp
> electronics' and 'speaker' emulations, turn up the gain knob all
> the way and feed the unit a sine wave fading in from -oo to 0 dB.
> i can create this fade in a file if needed, or you can use the Sin
> plugin that is part of caps. from this recording, we can deduce its
> clipping characteristics (best is to have a two-channel file with
> both input and output of the unit, but it's not a strict requirement).
> 
> -
> 
> these recordings will be of great help to anyone who is working on amp
> emulation, so even if i should fail miserably, the next one to work on
> it has valuable data available.
> 
> cheers,
> 
> tim

Hmm... doesn't sound too difficult, I'd like to do it.  Only complicated
part will be getting a sine wave like that into the thing.. I'm not
blessed with anything better than an SBLive I'm afraid. :/

I could model my real-life Mesa Dual Rectifier too if you like..

-Dave




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