linuxaudio.org

On Tue, September 28, 2010 5:47 pm, Jan Depner wrote:

quoted text
>

> On Tue, 2010-09-28 at 18:22 -0700, Patrick Shirkey wrote:

>> On Tue, September 28, 2010 7:33 am, Arnold Krille wrote:

>> > On Tuesday 28 September 2010 16:21:48 Patrick Shirkey wrote:

>> >> I'm pretty sure that this is the reasoning behind going with the

>> filter

>> >> option. The resources are available even on a eeepc as Ken has

>> reported

>> >> so

>> >> it is not really a big deal as jamin is intended for use post pro.

>> >

>> > I don't actually remember Ken saying that he runs jamin on his eeepc.

>> > True, he

>> > is running an awful lot of software on there, but I doubt that he is

>> > adding

>> > 10ms artificial delay from jamin to his live-setup...

>> >

>>

>> Good point. Maybe Ken could clarify if he used his eeepc for the

>> mastering

>> stage on his album?

>>

>>

>> >> If you want to have it running during production then you should

>> >> probably

>> >> just get a very powerful machine or invest the time to correct the

>> >> issues

>> >> as near as possible to source.

>> >

>> > Yes, a 1.8GHz turion64 running jack (3x1028@48kHz) and an ardour

>> session

>> > with

>> > two stereo tracks, 4 plugins (SC4-compressor and an eq for each

>> stereo) is

>> > to

>> > weak to also run jamin.

>> >

>> > Please get a grip! I am not using jamin on an under-spec machine. And

>> I am

>> > not

>> > mis-using it during mixing/recording of a >48-channels session either.

>> I

>> > even

>> > stopped dreaming about using jamin for live-foh usage (because of the

>> > delay

>> > introduced by the filter).

>>

>> Well, it was never designed as a foh tool. It is and always has been a

>> stereo channel post prod tool.

>>

>> When it was developed I was running a 1 ghz celeron. It ran on there

>> without issues. I don't see why it would have problems on any recent

>> (past

>> 8 years) notebook/netbook or PC.

>>

>>

>> > All I am saying is that jamin takes up a good amount of resources for

>> its

>> > processing. [*]

>>

>> This is by design. When the 2 very experienced DSP engineers Steve

>> Harris

>> and Jack O'Quin and the very experienced mastering engineer Ron Parker

>> spec'd the backend they decided that this was the most appropriate

>> method

>> given the available resources at the time.

>>

>> The idea was to provide as much smoothing of the bands as possible to

>> create a very "clean" sound as per traditional mastering technique.

>>

>> Now if you want to use a tool that is designed explicitly with that goal

>> in mind then you should definitely be considering jamin as an option.

>>

>>

>>

>> > And I combined Fons' argument that the filter used is not a good

>> > implementation

>>

>> Which has not been corroborated and in fact has been out right dismissed

>> by my contact here.

>>

>> > and probably not needed anyway with my idea of a simpler but equally

>> > useful tool.

>>

>> I think it would be worth your time to build a little mock up with pd or

>> jack rack and listen to the difference in the audio quality.

>>

>> I have very good reason to trust my sources that Fons is not correct

>> when

>> he says the current implementation is defective.

>>

>> The point about using a stand alone parametric eq plugin as you

>> suggested

>> is that it would definitely add artifacts to the end result which is why

>> the decision was made to use the linear filter.

>>

>>

>> > [*] It would be uber-cool if one could switch off that analyzer-view

>> to

>> > save processing cycles.

>>

>> That is a good point. I know you have the skills to make that happen. Do

>> you have the time to craft a patch?

>>

>

>     Since the analyzer view is only redrawn by default 10 times per

> second there really isn't much overhead to save.  Take a look at

> draw_EQ_spectrum_curve in hdeq.c.  You'll see that all it's really doing

> is drawing a predefined pixmap, converting 1023 levels to dB, and then

> drawing 1023 line segments.  This is hardly a drag on any system.  Be

> that as it may, you can adjust the frequency of the update in

> Edit->Preferences to be any value from 10 times per second to 0 times

> per second.  In other words, the ability to switch off the analyzer view

> is already there.

>

Good point, thanks for the reminder.
Yet another reason why nothing has been done on jamin for a while now ;-)
--

Patrick Shirkey

Boost Hardware Ltd.
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