ReRe: [linux-audio-user] Demudi looking good, soundcard advice? (tweaking jack?)

[MarC]

Emiliano Grilli wrote:

>venerdì, 15 ottobre 2004 alle 00:01:21, MarC ha scritto:
>  
>
>>I was looking also for a sound card for audio, well supported in Linux 
>>(specially under Demudi),
>>so I really apreciated your comments.
>>
>>However I've got some more questions which I state below:
>>    
>>
>
>(cut)
>
>  
>
>>I must say first that I'm an ignorant about technical sound issues (but 
>>I have some knowledge about electronics and spectral analysis so I 
>>should be able to learn it some day...). This explains the nonesenses 
>>and atrocities that I may have written below....
>>
>>For my case, I guess that I should try Delta 44 as I don't use digital 
>>I/O.
>>    
>>
>
>I would choose that only if I really needed 4 inputs and 4 outputs usable
>at the same time, otherwise I would check the audiophile.
>
>Consider also that with a multi I/O card you want to have a mixer with
>direct outputs per channel or at least inserts or groups (eg a way to route
>4 indipendent audio channels from the mixer) - and this is a feature that
>will rise the price of the mixer...
> 
>  
>
I take notes of it. I though I could do without the mixer and have
multiple input ( useful for some elemental drums recording or parallel
processed realtime voice+guitar). But as I see, as I don't run on a good
budget and what I need is to record guitar and voice (which can be done
one after the other), I prefer to record one track in good quality in
spite of recording 4 karaokes at the same time...


  I took a look to the "Midiman/M-Audio Audiophile 2496" and seems
  perfect for me.

(if anybody else is interested, I found a good review in
http://www.digit-life.com/articles/maudioaudiophile/)


  Thank you. Anyway, as you said I'm going to first learn how to tweak
  jack for my Audigy and get a mixer.



>>Now I'm ""working"" with a Creative Audigy card and I want to buy a new 
>>one basically because Audigy doesn't allow realtime monitoring through 
>>jack (the latency is at least 45ms and for me is too much) and because 
>>I want to have a good dynamic response to record my acoustic guitar 
>>(now it saturates the input or I must record at a low volume with a lot 
>>of noise).
>>    
>>
>
>Very strange that you cannot achieve better performance... I don't know the
>audigy, but with a crappy sb128 on athlon 800 w 256Mb ram I can get
>with "reasonably few" xruns to 23 ms and even to 11 (i speak of the values
>reported by qjackctl) - I suspect that your problem comes from not having
>an external mixer for conveniently routing of inputs and outputs and for
>monitoring what you are playing.
>
>Could also be a problem of a not enough powerful pc?
>  
>
it's not a problem of the pc: 2.6Ghz, 512Mb ram
it's a problem of *me* configuring it... :(
as Free knows, I already suspected that I had some problems with my jack
configuration so this comments are the definite proof of it.

Indeed, I *could* configure qjackctl with a latency of 23ms(periods: 2,
frames: 512 ): but I when I used Ardour I got some problems like the
sound getting cut sometimes, it hanged often, strange inicialization
errors, etc.
Also I though that I shouldn't allow any "xrun" and I disabled "Soft
Mode". Now I see I "must" allow "xruns" but what criteria do I follow?
how much "xruns" can be allowed?

And finally, to tweak jack configuration, I ignore if it can be useful
to change other parameters.
Now I only play with "periods" and "frames", and I don't know the exact
influence of the parameters: "Start Delay"(why jack has an initial
delay?) and "Timeout"(of what? it sounds the same than latency...). I
didn't found docs about jack about these issues... Does anybody know?
Should I try the jackit user list or it is too technical?

If there isn't documents on these questions, when I'll finish, I'll try
to write it down and make a "beginner's" doc.
Also I think that it should be a place where the people could post their
experiences in different sound cards in linux and their jack
configurations under different environments. This should make our life
easier...

>The cards I mentioned have all a "direct monitoring" feature, that will
>bypass the software, so in this they are better... but you definately need
>a mixer to enjoy these cards.
>
>I would for now try to exploit the audigy (I'm sure it can do better), and
>buy the mixer in first place, then the soundcard.
>
>  
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>>This could be a good option for what I'm searching for? Should I buy 
>>any other external hardware to record acoustic guitar without 
>>saturating the input? I'm always affraid of external mixers or 
>>amplifiers as they are very expensive and add noise to my signal. 
>>Anyone can help me destroy this myth?
>>    
>>
>
>There are micro mixers (behringer for example) with 6 channels (2 with
>phantom power) starting around 75 euro, as usual, the more you can spend,
>the better the result (good mixers are makie and soundcraft, for example) -
>but those micro mixers are handy and not very expensive for what they offer.
>
>  
>
ok. again, great thanks.

>>[for the electric guitar I currently use an expression pedal which 
>>outputs "line level" -> it goes through a Red Box Pro (DI) -> I connect 
>>it to the "mic input" but for the acoustic guitar I only have a mic 
>>output and I cannot go through the red box...]
>>    
>>
>
>I wouldn't connect anything than a mic to the "mic input", instead use the
>"line input", you should get better results with line level signals (which
>I suppose is what is coming from your guitars).
>
>The best you can do is a condenser microphone (samson are cheap) to record
>the acoustic guitar "thru the air" (here enters the pc noise, too, if you
>are in the same room ;).
> 
>  
>
I hope it will have some directivity (at leat 180 degrees) to avoid the
noise of the PC...
I'm going to take a look at the "samson".

>>And finally, 24 bits are enough?I guess it may influence in the range 
>>of different volumes that you can record (-> to solve the saturation 
>>problems with my records of acoustic guitar)
>>    
>>
>
>It's good (I often use 16 bit, because I don't do too much editing and for
>distributing sounds you always have to resample to 16 bit)
>Consider that with 16 bit you get 65536 possible values, with 24 you get
>16777216 for each sample - so is really best, but a bit unpratical -
>especially in home productions...
>
>Having more "bits" if I understand correctly helps you when you do lots of
>transformations to the sound, where with less bits you get a greater loss
>of information (but here I can be wrong)
>  
>
fine, as I see dynamical range is an affair of the sound card input.

>  
>
>>great thanks in advance!
>>    
>>
>
>HTH ciao
>  
>

Cheers.