REW Update

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I am constantly unpressed by the guy who develops this, especially as it is supported only by donations. I urge all users to send him a donation.

Cheers

Ian
 
Completely agree.  I'm happy to say I have, and will be doing so again in future  :)

I'm just having a look at the latest update now ...  have been nearly completely amazed by the improvements in the last couple of releases.

Useful scope stuff is very difficult to do on a personal computer, generally speaking, so I'm really interested to say the least.

REW's stable high sampling rate and asio capabilities may well make 'scope applications a reality ...  here's hoping!
 
Five minutes later  [ with REW Version 5.20 beta 7 ]  ..

The 'Scope' function is very nice ...  I'm just doing some testing in my lounge for now, monitoring my guitar channels and such, but I have to say, the screen updating of the 'richly varying' analog signal is pretty satisfying! The 'Persistence' setting is very, very nice.

I like the 'Ch1-Ch2' capability, with a bunch of 'math function' to boot ..  very interesting indeed.

So that's my first 5 minutes  ..  awesome on the 'Scope' new functionality.

Double plus good with a fair chance of further upside!
 
Triggering capabilities are quite impressive - with a musical transient (like a plucked guitar string) it is superb ..  the REW 'Scope functionality captures the transient amplitude envelope brilliantly  ...  and seems to use intelligent display choices to give a nice 'stationary' snapshot  ..  combined with pretty fast 'trigs/updates/refreshes/historicals' on tap, it makes for a very usable scope indeed.

I can't say I've seen such a 'great handling' analog waveform display on a pc before,  that so much does 'what I wan't to see'    (and not think about)

Sort of combines 'real time' updating, triggering and hold functions together with 'history' in a lovely way.

I could use a  'REW Gate with Hysteresis'  audio plug in right now  ;D

....

Looking forward to checking out my 'limiter'  builds'  transient performance with this  ..  on the 192KHz sampling rate.
May finally 'see' some real action for my '660 type fastest attack setting  :)

I can surely see a lot of potential for this tech in top shelf daw plugins, no doubt! 

...

I love the fine and responsive control for the vertical amplitude scales ... very snappy and updates the displays just like you expect.

I'm yet to check the 'Scope  against my bench  CRO, meters and such, but given REW's historical penchant for superb accuracy, I expect the 'mV/div' displays will be accurate to a very high level of confidence.

Ditto for the control on the horizontal time scale ...  time 'zoom' is super responsive.

...

Not to mention, is the nice overall  'sizing' that is available for the main  'Scope window  ....    again working just as you expect, refreshing the trace(s) accordingly, as you really open up the window  ... on the  big screen  :)

Love the 'draggable' vertical and horizontal  display    'position offset'    thingies too  ...  seriously cool.

And the 'mouse scroll wheel' on the horizontal time display is a 'pro' touch.

As is the 'dragging' of the whole display on the vertical amplitude scale  ...  I mean, wow.

...

Last but not least, some 'cursors'    ...  I can see some for the horizontal timebase, complete with read-out of  measurements of different types  (period, frequency)  ...  super great. 

However, not seeing any measurement cursors  for the vertical scale  or  readout of such, but can't expect the moon in just one release update now, can we ?

[ that would be the piece-de-resistance both in this new 'Scope functionality
    ...  and how great it could be in the 'RTA' section too ]

UPDATED : found it!  The vertical cursor function is there and it's brilliant  8) 8) 8)

...

The  'Snapshot' capability looks to be good ...  for a first glance  ..  some editability ..  although for serious annotation, I like post-processing the snap with a really good 'snap' app  .. 

I like 'Snagit' on my win pc, with 'after edits' of the filename to indicate the baseline conditions and what nots  ..  for posterity  .. 'the ages' :)  ..  kind of like 'poorman cvs'  :)

....

One other thing, I need to check, but my impression is that there is also an improvement in the 'RTA' application ...  I fancy that the occasional 'buffer glitch' I would always see is no longer evident.

Have to check that out some more,  over a couple of different installs, however ...  I can be optimistic and say I'm not getting it here at all.    I'm using a 3yr old  pc :  amd cpu, fx 8 core 16 gb ram, ssd system drive with win7-64

....

So far, Mr Mulcahy and REW Team don't disappoint - what a cracking update, is this 'Scope' functionality  8) 8)

Sheer brilliance  :eek:   
 
Having a look now at REW 'Scope functionality with some steady tones  ..  sine, sq etc from the 'Generator (with analog loopback) ..

All look really good - no sign of 'jaggies' or other obvious display artifacts at all.

96kHz 24bit - all working solidly with no issues for me.  :)    [decade++ old  motu 2408Mk3 asio drivers on amd pc]

Here's a pic of the 'Scope with a loopback signal from the 'Generator, analog bal I/O (asio drivers) square wave of 1KHz with the 96K/24bit operation ...

Clearly shows the transient response of the square wave with the overshoots etc.  Not bad at all really. I'll be looking at my bench generator with this 'Scope shortly too.

Well, it was more 'square wave' looking befoor I zoomed and cursor'd for an exact 500us (1kHz)  view. Very satisfying.

...

Also, the 'Scope has the ability to freely move a captured display on the horizontal time axis, and anywhere within the entire 'trace buffer'  subwindow  ....  very nice indeed  ...  along with the cursor measurements ... makes it easy to focus on/manipulate and measure time periods of interest  ...  for any desired interval in the trace history  (which is around 743ms for this fs 44.1KHz)

...

Speaking of the  trace buffer length, I wonder if it is settable ?

Some more length would be seriously great for capturing the horrible 'mains supply tics', around my noise floor,  that have beplagued me for the last decade ..  they have a periodicity of near 2s and are very short duration ..  on my 'rural' elec supply  :p

Perhaps that 'memory setting' that REW asks for at install time, affects the trace buffer length. I'll check that tomorrow.

...

With the vertical and horizontal cursors plus measurement readouts, this REW 'Scope can give my analog CRO a serious run for most things  [ signals within the analog limitations of the audio interface, of course etc ]

REW 'Scope seriously exceeds my CRO in vertical sensitivity - it has no probs at all with 1uV / division 

....  whereas my CRO goes down to 2mV / div or 40uV / sub-div  (with 5 subdivs to the div on the CRO graticule)

SO, looking in great detail at noise signals becomes quite easy ..  you can clearly see  noise floor modulation, for example, and use the timebase cursor and display shifting to accurately measure the lf modulation period and hf osc freq.

That's going to be very interesting on some of my builds for sure!

...

Also, when displaying both CH1 and CH2, you can shift them vertically seperately, which is great to seperate them out for easy viewing, or you can shift them on top of each other  ...  just like a real CRO. 

They remain locked together in time with any timebase operations affecting them both.
 

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Just found the 'vertical' measurement cursors ....  brilliant!  :-*

Here's a snap of noise floor at 10uV/div with both CH1, CH2 displayed, shifted vertically for clarity and with both measurement cursors for time/freq and voltage.

There are 3 seperate vertical cursors available, one for each Ch1, 2 and a third for the CH1 math CH2 trace. It doesn't appear to maintain the 'last set cursor' values for each, however ...  it applies the 'current cursor' settings in turn to the selected traces  ...  no biggy.

And that's just the 'manual' cursor mode ...  the 'tracking' cursor mode auto sets the top cursor of the vertical measurement band as you move the time cursor along ...  to the waveform amplitude at the time cursor.

If you drag the whole waveform around (as opposed to the time cursor) it widens or narrows the vertical measurement band
ie. both the top and bottom voltage cursors are adjusted.

Just amazing imho.


 

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All the waveform display machinations are way snappy with the updates - the overall experience is very responsive indeed - and that is no mean feat in any language, any where, any time  8)

...

I've been taking a break from the diy journey for the last couple of months ...  all that hot season rural fire hazard biz and some concurrent family things have had me ducking for a few months of downtime ...  worst summer ever  :mad:

But I have to say, once again, this latest  'new REW tech'  has me keen to 'get on up' and get moving ..  one more time! ;D

'Over here, over there!'   

Tomorrow - back to the bench.

...

And another donation is well in order,  for this is really classy work from the team
 
And how about the  'RTA function window  'list of vertical units'  available  ...  does  V/sqrt(Hz)  in freq domain !

It's just 'all too beautiful'  :)
 

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I could use that! 

... addendum  :  donated another increment to Mr Mulcahy and REW Team .... dang it feels satisfying  8)
 
Just had a chance to check the scope function, and sure enough its a delight to have a scope window and spectrum window up side by side on my wide bench monitor - something I will do from now on when amp bench testing, especially to confirm the onset of peak clipping on any side of the waveform.
 
re the dither function and noise floor ....  ditto here. I have to check that out some more.

Have the latest r20 download now and having a looksy ...
 
Im only just getting my teeth into it  ,
Im using the centrance axe port pro  , with a most favorable position of the controls Im getting in the region of 0.002% thd on loop back , opperating at 96khz/24bit asio driver  ,the headphone output providing the signal source might be the weak link in this case I might try a discrete digital out with external D/A as my signal source tomorrow .

I couldnt get 24 bit opperation at all under windows 7 ,but this of course relates to my sound card and drivers not REW itself,on XP I was able to get proper asio Centrance driver  96khz 24bit ,and THD figures sharply decreased on loop back .

How the USB sound module is powered makes a difference in the performance in relation to noise ,it wouldnt power on usb bus power from the laptop , then I rigged a common usb mains 5 volt 500ma switcher supply ,then 4xNimh cells ,making physical contact with the metalwork of the interface lowered induced noise around 30db ,and battery supply showing less spikes and harmonics 

The Cal procedure worked very nicely ,and the stepped response measurements with H2 and H3 graphed off below  is great , but what seemed to be missing was the abillity to provide outside known cal references  . Visual Analyser for me still holds its own for its multimeter style gauges freely scaleable in v,mv,db etc ,and the easy way it had to introduce a known reference from an external source. Seems like VA is a few years without an update at this stage and my particular audio drivers dont seem to work well  ,REW's RTA is jaw droppingly awesome , Dist. panel  is a revelation in sound .

I think really it all comes down to analog front/back end as to what you can achieve in terms of 0.00...% and below thd ,

Passive analog filtering of the generator output might allow an order of magnitude better test signal .

Ive fantasized already about a usb based circuit probe for REW , axeport pro sorta does that , its about -3db down at either end of 20hz-20khz with a meter of co-ax  , noise is about -100db , the thing is down at this level of magnitude residual power supply gash impacts the %'s thd , I might try 6 cell battery pack regulated to (780)5 volts and ground next to see if the noise can be reduced further .
 
Yes I use 6V and 12V small VRLA monoblocs as I have them easily available.  I sit a battery in an aluminium baking tray, along with the non PC parts as a way of reducing background noise ingress.  I can battery power the USB soundcard, as well as a USB isolator.
 
I tried to watch this thread, but lost track of everything...lol!  Does REW run on older (XP) machines...and if so which versions?

A friend "gifted" me a WIN XP laptop ...seems to now have a minimal installation..which was GREAT so my ancient HP scanner is once again usable and I can again use the TubeCAD design app...both apps died going into WIN 7 and later.

Ian...you mentioned a Focusrite (???) interface that you use which connects via USB.

Lazy boi here....trying to not dig through many postings!

EDIT:  The XP machine will NOT EVER be connected into the Internet.  Anything in/out will be done with USB SneakerNet.

Bri
 
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