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Author Topic: Audio simulator software  (Read 3647 times)

joecool85

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Audio simulator software
« on: July 13, 2012, 08:09:24 AM »
I've seen that you guys have talked about simulating circuits, especially preamp pieces, to check for frequency cuts/boost etc.  What do you guys use to simulate these circuits?
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phatt

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Re: Audio simulator software
« Reply #1 on: July 13, 2012, 08:33:11 AM »
http://my.ece.ucsb.edu/bobsclass/2C/Simulation/circuit_maker.htm

Free up to 50 components. :tu:

Gives one enough to work out the basic concept of whatz happinin inside.

put me light years ahead in a very short time.

Don't be fooled you still need to test the circuits on a test board as there is always something waiting to catch you out.

Joe it took me all about a hour to simulate your favorite K-20X preamp which told me the basic response curves of that circuit.

Once you have built the test circuit you use the sims to work out where/how to improve the result.
After you have found your way around a few circuits it does not take a degee to work out a few basic response curves.
too much bass here or too much gain too early in the path ,, all this stuff can be SEEN in pictures,, so you don't need to work out complex maths.

( I have no doubt that knowing the maths is a better way to go but I aint got enough time left in this life to go back to skool now ,, so call me a cheat :P)

Reading lotsa books was a great help but that was before the net and as I've found most of what is needed is to be found on the net these days ,, but still hard to beat a good book,, less chance of distractions 8|.

C maker is only one of many so hunt down a few and see which one works for you.
Cheers mate ,,, Phil.

ED,, Did you mean the fancy ones that you pass a signal into and HEAR the result?
« Last Edit: July 13, 2012, 08:34:43 AM by phatt »

KMG

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Re: Audio simulator software
« Reply #2 on: July 13, 2012, 08:38:09 AM »
I use LTspice, it`s free of charge, and good enough if you get adequate component models (especially for vacuum tubes).
It also allows to pass through circuit WAV files & record result.
Note, processing 20 sec WAV file through tube preamp ENGL530 takes about 30 min.
http://www.linear.com/designtools/software/#LTspice

phatt

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Re: Audio simulator software
« Reply #3 on: July 13, 2012, 08:56:00 AM »
Thanks KMG,
Yep I've heard a few but I just have a heap of trouble getting my head around it.

Now correct me if I'm missing something but sound cards surely comes into this setup and from what I've understood they are not at the top of the ideal high speced test equipment to be found.

Surely no self respecting audio geek would use a sound blaster card for testing audio?

Now I have no doubt the software might be able to replicate the result but the hardware might not be up to the task.

For me I'd rather spend the extra time and setup the real circuit and hear it through real speakers.
Thanks, Phil. 

Roly

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Re: Audio simulator software
« Reply #4 on: July 13, 2012, 09:04:14 AM »
Well the first has to be Duncan's Tone Stack Calculator.  This is what it does, this is all it does, but it does it brilliantly.

In general circuit modeling Spice has been around for a long time but you either had to pay through the nose or put up with student cripple-ware.  Well now there is LTSpice which is full-featured and FREE.  Its only drawback is that as it comes it has component libraries limited to Linear Technology devices, however adding to those libraries is easy, and there is a very active Yahoo users group where some seriously beefed up libraries and models can be downloaded.

And as Phil says, all this, and you don't need any maths - but when you do need to do a bit of math another tool I make quite a bit of use of is SpeQ Math which is like very full-blooded "calculating paper", and does a lot of graphing functions too.

PS: I've yet to encounter a soundcard I would rate above "just average" and while I'm sure somebody somewhere makes a truly high quality sound card, when it comes to using computer-based instrumentation such as signal generators or CRO's the sound card is  the major weak point.  Mind you, if you write a high definition sound file you can always port it out to something that will do a better job.
If you say theory and practice don't agree you haven't applied enough theory.

KMG

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Re: Audio simulator software
« Reply #5 on: July 13, 2012, 09:27:29 AM »
Simulator is very useful when you creating "skeleton" of your schematic.
It reduce time to adjust component values.
Final tuning of course must be done in "hardware".

joecool85

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Re: Audio simulator software
« Reply #6 on: July 17, 2012, 03:14:34 PM »
I have LTSpice and have used it for circuits where I'm simply passing voltage.  IE - my fan controller circuits.  How would I use it to see what frequencies pass through?  IE - hmm, too much lows, or not enough mids etc?
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KMG

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Re: Audio simulator software
« Reply #7 on: July 17, 2012, 04:15:30 PM »
Simply select "AC Analysis" instead of "Transient" in "Edit Simulation Command" dialog.
Put voltage source at circuit input. Set "AC Amplitude" = 1 in advanced dialog for it.
Run simulation & see frequency response in any point of your schematic.

joecool85

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Re: Audio simulator software
« Reply #8 on: July 18, 2012, 09:19:02 AM »
Simply select "AC Analysis" instead of "Transient" in "Edit Simulation Command" dialog.
Put voltage source at circuit input. Set "AC Amplitude" = 1 in advanced dialog for it.
Run simulation & see frequency response in any point of your schematic.

I'm going to have to try this...
Life is what you make it.
Still rockin' the Dean Markley K-20X
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