Proposed P.C. based spectrum analysers

[fotios]

I search for a spectrum analyzer for frequency response measurements, for THD+Noise measurements, mainly for preamplifiers and power amplifiers. I cannot expense a lot of money for his purchase and thus i am directed in P.C. based instruments. National Instruments has proposes to me two or three USB or PCI data acquisition devices but i do not know if they deserve the money; that moreover appears enough high. Without fail i would want an analyzer of Audio Precision but his cost is exceptionally high for my economic place. I cannot expense 6000€ for his purchase. Have does somebody under his experience it proposes to me something good and inexpensive, something that it could buy a DIY fan?
Thanks in advance
Fotios

[fotios]

No one proposition yet? Nobody knows something to help me? Only 39 views and nothing else?

[lineup]

Originally posted by fotios
No one proposition yet? Nobody knows something to help me? Only 39 views and nothing else?

I have a very wide range of topics
that I have commented on in Audio.

Have a look at my Everything Else topic about 'Zelscope'
a low price oscilloscope software (with 14 days trial).
I have even published my Screenshot of one of my Spectrum Analys = fourier

This software uses you sound card.
Has max 44.100 samples per scond = CD quality.
This is a bit low for squarewaves testings.

But in my topic are links to other softwares.
With higher sampling rates.

Lineup Audio Lab
and lineup
presents an original Audio Topic .. with useful information:

Zelscope for $20 - Windows software scope!

[Mr Chris]

You could try HigherFi.com / Free items / HiFi Software - Audio Test Bench.

[KJ42]

Hi,
two alternatives comes to my mind:
1) the cheapskate solution: Visual Analyser from Sillanum Software, a software scope, FFT analyser etc. for your soundcard.
2) Pico Technology, commercial but relatively reasonably priced PC-based instruments.

regards
KJ

[DRC]

I don't think pico make anything suitable now. They used to produce a 16 bit @ 300khz ADC but they have stopped making it now. A good soundcard 24 bit @ 192 khz can give very good results for minimal cost

[tubetvr]

Hi,

I use something called audiotester http://www.sumuller.de/audiotester/ which is a cheap SW for PC together with a sound card from Terratec that I have modified somewhat for lower noise. With this simple combination I get ~110dB dynamic range from DC to 48kHz and I can measure distortion, (THD, any separate overtone and IM) frequency response and swept distortion.

If you can accept the limitations in dynamic range with this kind of solution I think you will have difficulty to find something that is as costefficient.

BR Hans

[fotios]

Thanks to all for the advices, i had already 3 spectrum analysers with scopes, based on the sound card of my P.C. I have download and the softwares that you propose. And my sound card is a S.B. X-Fi Platinum. The test results was disappointing again. The problem with sound cards is not owed to the D.A. converters that contains but in the analog front end circuit of his inputs. They present a very high TIM distortion. I think that is better to make 3 notch filters at 100, 1000, 10000 Hz and i use my trust digital oscilloscope. Have anyone ideas about passive (not active!) notch filters?

[KJ42]

Originally posted by fotios
Thanks to all for the advices, i had already 3 spectrum analysers with scopes, based on the sound card of my P.C. I have download and the softwares that you propose. And my sound card is a S.B. X-Fi Platinum. The test results was disappointing again. The problem with sound cards is not owed to the D.A. converters that contains but in the analog front end circuit of his inputs. They present a very high TIM distortion. I think that is better to make 3 notch filters at 100, 1000, 10000 Hz and i use my trust digital oscilloscope. Have anyone ideas about passive (not active!) notch filters?

For improved analogue front-end you might consider external ADDA solutions. I am currently testing the Behringer SCR 2496. Due to excessive jitter in the optical output from my soundcard, I have ordered a second SCR (since the SCR does not want to perform the task as master clock in ADDA mode (which actually is DAAD mode).

The X-Fi platinum cards have otherwise received excellent critics on their technical performance.

regards
KJ

[kambule]

choose the right sound card. See result from audio rightmark :

http://audio.rightmark.org/index_new.shtml