SRS - SR-1 Audio Analyser

[janneman]

Originally Posted by ashok

Is this as good as an AP-1 ?

Technically, it's on a par with the AP S1. Remember, the S1 was designed in 1985 or so, state of the art, but progress has been made.

BUT, the software of the SR is much, much better than the AP. The AP software S1.exe started out as a DOS program and was later ported to Windows, but the DOS pedigree still shows. Basically, with the S1 software, you set up the hardware through window panels for each module like genarator, analyzer, sweep, dig in, dig out, etc.
With the newer APx software, and the SR, you set up a TEST and the system hardware configures itself.
AP S1 s/w is a pain to configure and getting hardcopy output is awkward compared to modern apps.

I have an S1, I love it for many reasons, but objectively it is outdated.

jan didden

[Hardi]

System one works perfectly and very comfortable with APWin under Windows using ISA-Win, PCI-Win , PCMCIA for Win or the "hacked" parallelport driver for Win98

S1.exe is a torture and really outdated.

[jackinnj]

A few weeks ago AP was having a sale of refurbished units.

[E007]

Just now, I checked the datasheet of SR1,

It is a high-performance audio analzer with fft function, so you could see the harmonics directly from the screen. may be a computer inside, and you don't need ext. computer connected as AP SYSTEM. It can measure -108dB THD+N, much better and advanced than AP system one and HP8903.

But it is still expensive to us here in China.

[andrewjm]

I certainly don't want to violate any DIY protocol by pushing my own unit, so I won't do any pushing. But as the senior engineer who worked on the SR1 audio analyzer I know a thing or two about it and if anyone would like to contact me privately with any questions about features, specs, technical details, etc. they can email me at ajm@thinksrs.com.


-Andrew

[SY]

Don't worry about it- any info you can give will be useful.

[simon7000]

Originally Posted by andrewjm

I certainly don't want to violate any DIY protocol by pushing my own unit, so I won't do any pushing. But as the senior engineer who worked on the SR1 audio analyzer I know a thing or two about it and if anyone would like to contact me privately with any questions about features, specs, technical details, etc. they can email me at ajm@thinksrs.com.


-Andrew

Have you followed any of my experiments on measuring resistors or cables?

ES

[andrewjm]

Originally Posted by SY

Don't worry about it- any info you can give will be useful.

OK then. To begin with, I'm not a marketing guy or a salesman-- just an engineer. So I'll keep this purely technical.

The SRS SR1 audio analyzer is a dual-domain audio generator/analyzer in a stand-alone box (no external computer required). On the analog side it has a 200 kHz bandwidth, balanced and unbalanced outputs from 1uV to 28Vrms (half that for the unbalanced outputs) and input ranges from 60 mVrms to 160Vrms. On the digital side it accepts and can generate AES/SPDIF signals with sample rates between 24 kHz and 216 kHz. The digital audio is not an option, it comes with the base unit. The generator can generate all the standard digital audio test signals; sines, phased sines, IMD waveforms, squares, ramps, noise, arbs, etc. The digital generator does a few more tricks like J-Test, rotating bits, etc.

In terms of analyzers the SR1 does the traditional THD+N/wideband ampitude measurements with variable filtering, single channel FFT measurements, true dual-channel FFT measurements (where we actually ratio the input and output ffts on a shot-by shot basis so you can excite a system with noise, for instance, and still make a measurement of its phase response ), Impulse response and quasi-anechoic frequency response, THD, multitone measurements, and more. You can run two 'analyzers' at once so you can simultaneously be measuring THD+N say, and looking at the spectrum of the residual distortion signal.

SR1 also does digital audio carrier measurements including carrier amplitude and frequency and has a really slick jitter analyzer that can look at total jitter or jitter spectrum (out to 100 kHz) with a really low jitter noise floor. You can also see and transmit all the consumer/professional status bits, including user bits.

No options so far. The only significant option is what we call the "digitizer" which digitizes the digital audio carrier at 80MHz and computes jitter and produces very pretty full-color eye diagrams.

The software is similar in approach to the AP2700 software, with separate panels that control various instrument functions. Some people have commented that SR1 is "complicated", but keep in mind that the instrument is aimed towards knowledgeable audio enthusiasts, not towards keeping things simple for technicians on an assembly line. There's a complete scripting capability built in (VBscript or JScript) and the instrument can be controlled remotely via Ethernet/Serial Port/GPIB (IEEE488).

I could say things like "-110 dB distortion" but as we all know specs like distortion are complicated things that depend on frequency, amplitude, and bandwidth and you really should take a look at the detailed specs if you've gotten this far. ( Audio Analyzer - SR1 )

Base price in the US $8400. (well that's not purely technical, but it's important)

I hope that clears up some of the confusion about what the SR1 audio analyzer is and isn't.

-Andrew

[coluke]

Originally Posted by andrewjm

OK then. To begin with, I'm not a marketing guy or a salesman-- just an engineer. So I'll keep this purely technical.

Hi Andrew - thank you for the info. Can you tell me something more about the analog domain filter and generator topology?

L.

[andrewjm]

Originally Posted by coluke

Hi Andrew - thank you for the info. Can you tell me something more about the analog domain filter and generator topology?

Analog generator is a 512ks 24 bit DAC followed by tunable analog filtering (to remove noise and harmonics) followed by the balanced/unbalanced output amplifiers. This gives both excellent frequency accuracy as well as low distortion. AD797s are used throughout the generator and input signal chain for best distortion performance. Generator channels are completely independent and can be set up with different waveforms if desired.

Analog inputs go into a low-noise low-distortion analog input amplifier followed by tunable analog notch filtering to remove the fundamental. Then there's some more gain followed by a choice of a 16bit 512ks or 24b 128ks ADCs (depending on the application bandwidth) and then it's off to a pair of Analog Devices DSPs . The analog notch filter is key to maintaining good dynamic range. Other filtering, such as bw limiting and weighting is done with digital filters.

Hope that's what you were looking for.
-Andrew