Hi,
I do have a set of the usual test equipment (rigol 1074 scope, siglant generator and DMMs etc) but even used audio range analysers are a bit expensive.
Some HP used units go for around 800-1000GBP on the well known site :S
I have seen people using an external windows software with the Analog Discovery 2 (costs around 220GBP I believe).
What do people use for audio measurements, distortion, impedance etc?
a) PC based solutions available?
b) maybe some dedicated hardware that used is cheaper? (that I dont know of)
thanks
I do have a set of the usual test equipment (rigol 1074 scope, siglant generator and DMMs etc) but even used audio range analysers are a bit expensive.
Some HP used units go for around 800-1000GBP on the well known site :S
I have seen people using an external windows software with the Analog Discovery 2 (costs around 220GBP I believe).
What do people use for audio measurements, distortion, impedance etc?
a) PC based solutions available?
b) maybe some dedicated hardware that used is cheaper? (that I dont know of)
thanks
I buy used hardware test equipment off the internet. E-Bay is a good place. Which test instrument depends on what project I am doing and what it will need for its development and testing. If it isnt a universal instrument, you can always sell it when you are finished using it.
For audio a good FFT type product will be needed. Such as the QA401.
-RNMarsh
For audio a good FFT type product will be needed. Such as the QA401.
-RNMarsh
https://www.diyaudio.com/forums/equ...er-ak5397-ak5394a-ak4490-259.html#post5730142
You can go cheaper than that with any sound card but it's not reliable on a long term.
You can go cheaper than that with any sound card but it's not reliable on a long term.
Most used of ebay (like HP spectrum analyzers that go down to 10hz or so) go for 800-1000GBP... :S
Any specific and cheap model to look for?
The older HP gear (HP 3561/62/63, HP8903, etc.) is quite good for its age. It's certainly nice to be able to push a button and have the frequency response shown. The input scaling and protection are handy too.
That said, the older HP gear offers 80 dB dynamic range, which is not enough to measure anything in the modern world.
A good external sound card (see Focusrite's Scarlett series) can be the ticket. That works really well, especially with line-level circuits (preamps, headphone amps). You can add Pete Millett's sound card interface for input scaling and (I think) protection, though, I don't know how much distortion the interface adds.
For the software, many use TrueRTA and it seems to be one of the better ones. I also seem to recall that the licensing cost is pretty reasonable.
As others have pointed out, the Quant Asylum QA401 is tough to beat. At $450, it's very tough to beat on price. Add up sound card, interface, and software licenses, and you're nearly there. In your shoes, that's what I'd look at.
The next step up is the Audio Precision APx515. Last I checked, they started at $6500.
Tom
That said, the older HP gear offers 80 dB dynamic range, which is not enough to measure anything in the modern world.
A good external sound card (see Focusrite's Scarlett series) can be the ticket. That works really well, especially with line-level circuits (preamps, headphone amps). You can add Pete Millett's sound card interface for input scaling and (I think) protection, though, I don't know how much distortion the interface adds.
For the software, many use TrueRTA and it seems to be one of the better ones. I also seem to recall that the licensing cost is pretty reasonable.
As others have pointed out, the Quant Asylum QA401 is tough to beat. At $450, it's very tough to beat on price. Add up sound card, interface, and software licenses, and you're nearly there. In your shoes, that's what I'd look at.
The next step up is the Audio Precision APx515. Last I checked, they started at $6500.
Tom
Hewlett Packard got more dynamic range out of their network analyzers by using a "pre-scale" method and a voltage controlled amplifier...at least that's what my HP3577a does.
I have the QA401, works great and I second the recommendation.
Sometimes you'll see "wave analyzers" from GenRad, Quantech or HP on EBay. These have switched (narrow) bandwidth, very good RMS detectors and high sensitivity. I have an HP3581 with a refurbished battery pack. It has a 3Hz narrow bandpass crystal filter so you can look at each harmonic!
- medium or hi-range price PC-soundcard can be ok. I mean $100-$200 or more. I use Asus Xonar Essence STX now for my distortion measurements.
(I started with Sounblaster Live 24bit, but it was not good enough for my purposes, then later I had E-mu 0204 - it was near ok for me, but I wasn't happy).
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You can be lucky and find a second-hand USB soundcard based on the AK5385 or similar, like the EMU0404 I have. This type of USB soundcard has received a lot of forum time and benchmarking for audio use. Such a module allows common low signal level inputs directly, as well as direct use of 1Meg scope probes to use 10:1 and 100:1 probes for valve audio work. Unless you were aiming for the highest of performance levels, then these type soundcard modules can go very cheap ($40 for me).
A USB soundcard can allow battery powering, including USB isolator battery powering to pretty much eliminate ground loop artefacts with typical mains powered equipment.
The last few years have seen free software like REW shoot away in ease of high end performance with so many audio related functions, and it has continuing development and forum support.
Well worth a look if you are in to low-cost 2nd hand gear. Lots of people looking and testing more modern new soundcard gear if you have the budget.
A USB soundcard can allow battery powering, including USB isolator battery powering to pretty much eliminate ground loop artefacts with typical mains powered equipment.
The last few years have seen free software like REW shoot away in ease of high end performance with so many audio related functions, and it has continuing development and forum support.
Well worth a look if you are in to low-cost 2nd hand gear. Lots of people looking and testing more modern new soundcard gear if you have the budget.
...if you are happy with being locked in to the proprietary QA software. The QA401 is not a USB Audio Class device, so it won't work with the plethora of audio analysis software out there.
I swear by my RTX6001 unit. Not exactly as cheap as the average "soundcard", but with much better audio performance, and works with just about any software. I am considering to get another one.
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