* Posts by John Robson

1041 posts • joined 19 May 2008

Page:

Hi-res audio folk to introduce new rules and weed out impure noises

John Robson
Silver badge

Re: Dan Lavry

@GaspardWinckler

The reasons for higher rate sampling and higher bit depths is for the recording studio, and for the post processing work.

For final playback - no point at all. For the steps before (and during) the thousands of processing steps which are applied to each track, before those tracks are grouped, down mixed, then processed, grouped and downmixed again, and again, and again....

After all of that you are grateful for the extra bit depth you used initially, the noise floor is still inaudible.

The higher sample rates are primarily used to reduce the cost of analogue filters (required to produce the bandlimited signal for encoding) by allowing a secondary application of a digital filter before downsampling (these filters are *much* cheaper). I imagine there is a minor lower latency benefit for digital processing internally in a live mixer as well...

0
0
John Robson
Silver badge

Re: This is an IT site

@GasppardWinkler

Archive away - but you still don't need to archive more sound than is audible. CSI "enhance" will still only be possible in hollywood.

The fundamental difference between audio and video is that we can change the spatial resolution of an image (moving or static) by moving it relative to our eyeballs.

When I buy/download/stream music why should I transfer many times more data than I need?

0
0
John Robson
Silver badge

Re: "a brave person who said that HRA has no audible benefits"

@ Neil Barnes

The reason we run at -18dBFS as our "new zero" is for recording headroom - there is no reason to leave it there when we export the finished article.

So that's 12 bits you can add back on.

The 11 bits for dither noise - I rather suspect that is not true.

On the basis that a guassian dither will allow you to hear a tone at well underneath a single bit of amplitude, albeit with some noise, I struggle to believe that a sane dither would *lose* 11dB of resolution.

There are *extremely* good reasons to oversample as part of the DAC (it makes the analogue side filters much easier for instance) and very good reasons to use higher bit depths (it provides an excellent noise floor and headroom when recording) - but for the product, CD quality is way past most of our hearing capacity...

0
0
John Robson
Silver badge

@John Geek - "at the nyquist limit (sample rate/2) there's ZERO phase information"

That's simply not true - all the phase information is perfectly preserved by sampling - right up to Nyquist.

There is exactly one band limited signal which passes through all the sample points.

3
1
John Robson
Silver badge

Re: Nyquist-Shannon

@DN4

A bandwidth limited wave is not necessarily periodic - we show periodic functions (whether sine waves or square waves) as they are easy to demonstrate (you don't need to do time synced overlays).

But a bandwidth limited waveform is purely represented by an appropriate sample rate. Whether it is finite in time or not. The FFT of the waveform would be harder to generate, but we're not trying to.

1
0
John Robson
Silver badge

Re: First move to lossless CD quality.

@Sebby - Personally I'm of the belief that you can never have too much information.

Can I interest you in my new TV standard - it doesn't just deal with the visible spectrum, but goes all the way to X-Rays...

There is a point at which information is sufficient. At the point where I can perfectly reproduce the full spectrum of visible/audio frequencies with a dynamic range to span 'barely detectable' to 'painful' then I can only add:

- Pain

- Information that is instantly discarded, since the receiver (the eyeball or ear) simply can not deal with it

7
1
John Robson
Silver badge

Re: "a brave person who said that HRA has no audible benefits"

@TheOtherHobbs - And I know from experience that the difference between a 24-bit master and a downsampled 16-bit master is absolutely and reliably audible.

There are only two ways for this to be the case:

- You are a bat.

- You're not doing it properly double blind.

OK, that's not fair - there is a third way - the 16bit master was mucked around with too much - adding dither noise at each step - that's why we record (ok, also to allow us to be cautious with gain settings) and master at 24bit.

Once mastered there is no reason not to down-sample to 16bit/44k, and every reason *to* do so.

To make it double blind you really need to make sure that your audio signals are at the same level to a ridiculous accuracy - because as salespeople know "louder is better". No really - even stupidly low differences (like 0.2dB, which is not consciously audible btw) show a distinct preference for the louder source.

14
0
John Robson
Silver badge

Re: Self confessed audiophile

@ Sgt_Oddball

It is possible of course that the Vinyl and CD versions were from different masters, so they will sound different, because they are different performances.

Tape and vinyl both have (and have always had) inherent limitations, which are far more noticeable than a 16 bit limit or a 22 kHz limit ever will be - so yes, I agree, they will sound different.

Now which you prefer is probably based partly on what format you *first* or "most significantly" heard the music from - or even which master you heard most...

18
0
John Robson
Silver badge

Monty....

This is all that needs to be said, and said much better than I ever could:

http://www.xiph.org/video/vid2.shtml

Oversample for the DAC, have 24bit depth in the studio before 10,000 rounds of autotune (other, useful, effects are available) but the human ear can't deal with more than CD quality - that's why it was defined.

The biggest issue is that all this high def audio will still be overdriven through 30p headphones (even if they are in a £300 case).

23
0

BT: Let us scrap ordinary phone lines. You've all got great internet, right?

John Robson
Silver badge

Re: One big problem

Mine can - and I've always had *one* plugged in that can, even when I basically only used DECT phones.

8
0

Tim Worstall dances to victory over resources scaremongerers

John Robson
Silver badge

Re: Vulture

Mic pack for an audience of 8.

If even one of them is Deaf/deaf/hard of hearing and uses a T loop then yes

If you want the video to be usable then yes

If you want to produce an easy transcript then yes

If you are pushing the video/audio to another room for the other attendees, then yes.

I don't see any reinforcement speakers, so I think we can assume that the mic is there for good pickup for other systems - rather than to assist with his vocal projection

0
0

Wake up, sheeple! If you ask Siri about 9/11 it will rat you out to the police!

John Robson
Silver badge

Depends...

On how Siri is activated. It may well be that the phone's owner is in some way incapacitated, and shouting to siri is their last recourse.

In which case "phone the ${expletive} ambulance" is more likely to be uttered...

6
0

Kamikaze Rosetta probe to ram comet it's chased for billions of miles

John Robson
Silver badge

Re: Rosetta is cool?

@ Why isn't Roesetta being cooked right now and how will it stay cool enough during the closest approach to the Sun?

Because it's spending much of it's time in the shade, and "it's cold outside, there's no kind of atmosphere"

How long it will survive is an unknown...

3
0

Pint-sized PCIe powerhouse: Intel NUC5i5RYK

John Robson
Silver badge

Gulliver-like

I presume you mean Brobdingnagian rather than Lilliputian...

Or do you mean Gulliver in Lilliput rather than Brobdingnag?

1
0

Germany says no steamy ebooks until die Kinder have gone to bed

John Robson
Silver badge

Re: So, Herr Regulator

And the Americans would be happy to oblige, or is that only in Vegas?

0
0

Post Office launches mobe service for aged greybeards

John Robson
Silver badge

More importantly - does it expire?

'cos if it does it's not prepay, it's just a rolling flexible contract.

2
0

Pew, pew, pew! Sammy shoots out updates to plug mobile keyboard snooping bug

John Robson
Silver badge

@1908s_coder

No - I feel your pain (still have Android 2.3 on my phone)

But *in this case* the cure is actually likely to be applied via the vulnerability - so it should self close pretty quickly.

1
0
John Robson
Silver badge

@1980s_coder

Either you're vulnerable since your keyboard downloads updates, and it will be autopatched, or you're not because it doesn't and it doesn't matter...

4
0

At last, switching between rubbish broadband providers now easier

John Robson
Silver badge

THe MAC (And PAC) were there for a reason...

As a naughty supplier I can just switch you now. No need for any compliance from the customer or the old phone company...

7
0

Reddit joins the HTTPS-only stampede

John Robson
Silver badge

Re: Third World Security

@Stuart 22

Absolutely agree with you - the level of bloat is ridiculous - but that's where a decent cache, with ad filters etc., can really make a huge difference. Even "large" CSS files tend to be relatively small (cf+ video) and are rarely downloaded (since they can be cached and apply to whole sites for months at a time), so I tend to excuse those ;)

The ongoing story about the education centre in the middle of Australia is a case in point. They have very limited network bandwidth, and poor latency. Having devices at both ends of their "connection" would allow them to filter out the ads and other garbage somewhere where there is good connectivity, and cache the resultant data in the building.

Those two measures maximise the usage of the limited connectivity, shared between many poeple, and even more sessions. The users are still able to go HTTPS when needed, but their experience over HTTP is better, so they'll use that by default for things that don't require the security.

Put everything HTTPS and you can't strip the ads/flash as easily, you can't cache it between users, you just have to eat the data which is shovelled at you, as your connection is overwhelmed.

Put HTTPS as an option by all means, those of us fortunate enough to have large gobs of bandwidth, no caps and limited numbers of users (i.e. reduced opportunity for caching) can then use it and fill up the central pipes with lots of "unreadable" data.

Enforce HTTPS where user data is being sent/recieved.

Leave HTTP as an option for those who need/want it (maybe even with an "HTTPS is available" banner)

0
0
John Robson
Silver badge

Whilst I see your point I am also very aware that there are places in the world that don't have unlimited power and network bandwidth.

There is a distinct advantage to being able to cache data - HTTPS everything breaks the internet for various locations...

1
0

Raspberry Pi guys want you to go topless in the heat

John Robson
Silver badge

@45RPM

Of course it's pedantry ;) We are still on El Reg aren't we? ;)

If you have an old Amiga 600 then rip it apart and put a Pi in. There are fairly easy ways to move ports around if you have a case with planety of space (I imagine that even a spectrum case would have enough space) with short extension cables. I know they're not all that cheap, but you probably only need the HDMI one - maybe a Cat5 if you need a wired network - maybe a 3.5mm audio cable. A powered USB hub will be needed for your SATA converter anyway, so that can be mounted near the HDMI output.

I like the look of the old Sun Microsystems disk array cases, so I have a couple with miniITX systems in them. They might get replaced with a PI2 at some point (but they're not in use at the moment anyway...)

But we're talking about "pet" projects now - rather than a mass production case. And aren't pet projects one of the main points of the Pi?

1
0
John Robson
Silver badge

@45RPM

A case can't provide a SATA interface, it could include a USB/SATA converter, and potentially a powered hub as well..

But USB has finite bandwidth, so you need some awareness of the requirements.

Grab a MiniITX chassis, pop 5V from the PSU to the GPIO (or the USB header if you want), add a USB hub in a 3.5" drive bay and HDMI/Network extension cables to the rear.

Seems like it would fulfill your criterion fairly easily.

3
0
John Robson
Silver badge

What I want...

@45RPM:

What you want isn't a raspberry pi then...

The ports are where they are, there is no SATA.

I'm sure you could pop it in an ITX case (getting you the various drive slots), add a USB HUB, and push the power in from the ITX PSU.

You could even add a small HDMI extenstion cable and Cat5 extension cable...

10
0

For fax's sake: Medic chaos as e-Referrals system goes offline

John Robson
Silver badge

Re: Can they NOT cock something up?

Viagra?

It's the one cock-up they would inevitably avoid

1
0

Philae warms up nicely, sends home second burst of data

John Robson
Silver badge

Re: Over engineered?

Lower launch costs are still *way* more expensive than building the probe - and the groundstation and the people required to run the probe...

Launch times are normally decided by solar system geometry, rather than anything so prosaic as a "when it's ready" judgment.

Travel times aren't measured in hours, they're measured in years... So when is your "backup" going to arrive? A few hundred years for the geometry to work again, then add on a few more for travel...

19
0

Wikipedia to go all HTTPS, all the time

John Robson
Silver badge

Re: Hmm...

@Charles 9 - With ANY in-the-clear transmission, your stuff can be altered in-flight by any relay.

I don't need to modify Wikipedia on the fly - I can just edit the page directly, that's kind of the point of a wiki.

And if I'm doing on the fly modification - I can probably make a nice certificate as well anyway - when did you last check the CAs on your browser?

Additionally HTTPS isn't the best solution for ensuring that data isn't modified in flight - that only requires (signed) hashes (which could be included in the page).

Just because you have a hammer in your hand doesn't make everything a nail.

0
0
John Robson
Silver badge

Hmm...

"Accounts may also be hijacked, pages may be censored, other security flaws could expose sensitive user information and communications"

Accounts may be hijacked - well clearly logins should always have been be over HTTPS

Pages may be censored - well, they still can - just go and edit it!

Security flaws - might still exist, so there is no net gain there...

Not quite sure about the justification here...

1
1

Cortana threatens to blow away ESC key

John Robson
Silver badge

At least replace caps lock...

Then I can rip out and throw away cortana rather than caps lock...

People get very confused by a keyboard with a hole in it - I'd map it to control, but I'm not allowed to at work :(

7
0

Use snooped data in court? Nah, says UK.gov - folk might be cleared

John Robson
Silver badge

Re: Is it just me...

@ MrXavia - Not really, all that would show is the CPS is trying to prosecute without sufficient evidence...

OK - Aquittals or dropped prosecutions...

2
0
John Robson
Silver badge

Is it just me...

or would an increase in aquitalls not also be a measure of success?

26
1

The Martian: Matt Damon sciences the sh*t out of the red planet

John Robson
Silver badge

Re: I'd watch it.

After Randall Munroe's recommendation (see XKCD) I did - the PDF is available with a "may be distributed freely" copyright notice at the rear.

Slightly disappointed with the rapidity of the ending, but otherwise a decent book...

0
0

Israeli firm gets legal on Indian techie over ISP ad injection spat

John Robson
Silver badge

Re: Bharti Airtel and Flash Networks

@AC: Injection of various assets to provide improved service (or pay for a free one), is common practice and people accept its benefits. Only those with tin-foil hats on or a very poor understanding of the real world get the panties in a bundle over it.

Absolutely - with the exception of when that injected content has a destructive effect on the content requested. In that case Flash Networks, and possibly Bharti Airtel could be accused of gaining illicit access to the product^Hcustomer's computer, in violation of various laws.

8
0

TERROR in ORBIT: Dodgy rocket burp biffs International Space Station off track

John Robson
Silver badge

Re: 1,922 seconds?

ISS isn't all that rigid - so a nice gentle thrust (liquid fuels, so easily throttled) means that you get the same deltaV with lower stresses on the structure. Oh, and IIRC better rocket efficiency to boot.

It's also quite heavy - gravity is about 98% of surface normal, it masses about 370,000 kg.

To raise it by 2,800m would take....

https://www.google.co.uk/search?hl=en&q=mass+of+iss&meta=&safe=active&gws_rd=ssl#safe=active&hl=en&q=370000kg+*+2800m+*+9.81m%2Fs%5E2+*.98

10 GJ

over 2000 seconds is 5MW

Not too shabby...

(Yes I've ingored the required deltaV for the different orbital requirement)

7
1

LOOK OUT, Brits – is that a Facebook LASER-GUN drone above us?

John Robson
Silver badge

Re: What every regime needs

Too slow for serious tests, but a good starting position I'll grant you

0
0

Obama issues HTTPS-only order to US Federal sysadmins

John Robson
Silver badge

Re: Why?

If it takes user data then it goes HTTPS - but for the most part we could do with HTTPA (A for authenticated) rather than S. Note that a selection of links "salary between" is considered user data.

As for someone finding out I'm on holiday - I don't put it in my out of office system, but it's still pretty obvious to anyone who walks down the road... I'd rather they robbed me while I wasn't there anyway.

Checking what benefits I'm looking for - are they for me or a friend/colleague? I recently looked up data on the married persons allowance - that potentially means I'm married, or that I might intend to get married, or that I know someone in one of those two camps...

Given that my marriage is a matter of public record anyway I hardly find that earth shattering.

I'm happy for various information to come as postcards, particularly as, by doing so, I improve the rate of delivery I get, and reduce the cost to the public purse.

2
4
John Robson
Silver badge

Why?

Not everything I use (UK) government websites for needs encryption (in fact the majority of it doesn't)

Certainly tax returns etc need to be secured, but checking the requirements for various items (passport application, driving license application, various benefits and tax breaks) would benefit more from a simple page, and a local cache than they would from encryption...

1
11

Paper driving licence death day: DVLA website is still TITSUP

John Robson
Silver badge

Re: There is no such thing as "Road Tax"!

@IsJustabloke - yawn

If people tried getting the terminology right people wouldn't have to correct them.

It's not hard - use the shorter word "car" where you used to use the word "road".

14
1

Screw you, Apple! We're still making phones no one wants – Samsung

John Robson
Silver badge

Re: Battery & Micro-SD?

My Desire S is still on 2 something.

Still, I get a week of battery life out of it...

0
0

Everything Apple touted at WWDC – step inside our no-hype-zone™

John Robson
Silver badge

Re: Shift Key

That would be lovely...

0
0

Voyager 2 'stopped' last week, and not just for maintenance

John Robson
Silver badge

Very low chance of discovery...

Interpretation - possible, but also fairly unlikely IMHO.

OTOH it still has FAR more chance than any of the "gold records" I've sent out into space...

4
0

Dodgy colon bug is a total pain in the butt for Skype users today

John Robson
Silver badge

Re: Keep history bug

Of course they keep it on the server - you think delete means anything more than "remember this message in a filter file for this user"?

At most it would be "add the 'deleted' flag to this message"

0
0

Science teacher jammed his school kids' phones, gets week suspension

John Robson
Silver badge

Faraday cage...

As soon as they enter the classroom?

Why not the school - you can claim them back for break times if you like...

3
0

Compromised SSH keys used to access Spotify, UK Govt GitHub repos

John Robson
Silver badge

Re: Why ?

I took all of my existing keys out of use, and reissued the lot, because I couldn't remmeber exactly when each had been generated (or necessarily on which machine).

But to expect that level of action from everyone with a github account?

In the same way I expect browsers to flag up bad certs I'd expect SSH banners to warn about these compromised keys - or simply ignore them (with error in the server log at least, preferably in the banner)

0
0

Strap-on fiddle factor: We poke ten Apple Watch apps

John Robson
Silver badge

Strava remote control...

Well, at that cost I'll get something else, but a simple 2 button BTLE device on the bars might be nice, then the tablet in the pannier can do the work for me, makes uploading fractionally easier - I'll pay up to £4, maybe £5...

Else I'll just keep using my GPS Logger.

0
0

Google launches native Android Smart Lock password manager

John Robson
Silver badge

Re: "A security boon for the masses"

No reason the built in version can't do the same (timeout)...

but that's just a second password - WIWTF with the passcode/pattern/word that you log in with.

Or is it actual two factor with the biometric - oh, no that's be an option along with the passcode, so fractionally weaker than WIWTF...

0
0
John Robson
Silver badge

Re: "A security boon for the masses"

Because it's only one step away from automatically filling in the password field for you on each site.

That means that an individual site failure doesn't compromise all your passwords. There is still a possible weakness in the chocolate factory to worry about, but this is a good first step towards better passwords, and lower reuse.

If someone is targetting my device then yes, they get my passwords - but that's no different from the situation now. What this does mean is that another moonpig doesn't compromise 3 million people's gmail, facebook and banking passwords...

4
2

Amazon reveals KiddieKindle and pocket money scheme

John Robson
Silver badge

Re: Oh, yum, more tracking.

Don't track my reading very much...

The WiFi is generally off (for battery life) and I load books from Calibre as much as anything else.

Every so often it will get the WiFi on for osmething, and at that point the "percent completed" for Amazon bought stuff will get uploaded no doubt.

Surprise Amazon - that book I bought 3 month ago - I've read it...

0
0

LightSail mission stalled by .CSV log file embiggenment SNAFU

John Robson
Silver badge

Re: And so...

Both...

They'll be diverting the csv to /dev/null, but the cause of this reboot was probably a cosmic ray flipping a bit on the electronics and therefore triggering a reboot.

That will happen again, but the csv file shouldn't be an issue in the future...

1
0

.sucks-gate: How about listening to us the first two times, exasperated FTC tells ICANN

John Robson
Silver badge

Re: How do they know who is registering?

Because this is in the "sunrise" phase - you can only pay top dollar now - when they open it to the public then you can pay $10..

0
0

Page:

Forums