Airport Express/Streaming Audibility Tests

sq225917 said:
How do you level match them, with an 'amplify' or 'normalize' transform?
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Amplify - that simply looks for the peak amplitude and allows you to ensure that the highest point on both tracks are matched.

Don't trust 'normalise' for this kind of test which seems too invasive.

Amplify should fully preserve any dynamic differences in the tracks, relative to the peak point.
 
sq225917 said:
Rob I can't pick anything as being really different with them. if pushed I'd say i prefer B, but feel I would struggle to chose it in an AB with any accuracy.
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That's interesting.

In this instance, A is the AE analogue file while B is the CD rip
The track is from a Naim CD.

Going back to point re the transform function used, I only apply this to the AE feed so as to ensure that the CD rip is as untouched as possible.
AE output is about 4dB bellow the standard so always needs some boost.

FWIW I also struggled with these two tracks.

Paul Ranson said:
I can grab some from the HD broadcast. Might make an interesting comparison.

Paul
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Will be recording to wav at 16/44 but then uploading the file as lossless - I think you prefer FLAC? (might as well keep them the same)
 
Rob,

I should try this again, now that the levels have been matched, but given that I know the answer I like B better.

Listening blind does have its disadvantages. ;-)

Joe
 
Mmm, despite not having anything tangible to really latch onto I still preferred the cd rip. How different are they via Diffmaker?

Good call re Normalise, it's most invasive, that's why i asked.
 
A quick listen, and first impressions, say - much prefer New C. .... Quite a difference, I think.
 
Why is normalize invasive? I understand normalize to simply amplify a signal to have a peak amplitude at the set level, and everything else is proportional. That is, it's just a plain amplification command, only you set the level you want the peak to be at, rather than the amount to amplify by.
 
The Audacity 'amplify' suggests a factor to make the max 0dB. But with this digital material normalize is (I think) equivalent. The three files I linked above are all amplified to match the original. Between 1.8 and 0.6dB.

Probably we should try punching it up a bit with more exotic effects...

Paul
 
Will be recording to wav at 16/44 but then uploading the file as lossless - I think you prefer FLAC? (might as well keep them the same)
Click to expand...
I'll be dubbing digitally from a Sky HD box. So native 16/48 I think. I've only a record of the second part. Perhaps we should select a tune as a basis?

FLAC is (I think) most open lossless compression. I'll look to see what else I can transcode to/from.

Paul
 
Paul Ranson said:
I'll be dubbing digitally from a Sky HD box. So native 16/48 I think. I've only a record of the second part. Perhaps we should select a tune as a basis?

FLAC is (I think) most open lossless compression. I'll look to see what else I can transcode to/from.

Paul
Click to expand...

Well it was a fantastic listen and I really hope they keep the 320 feed going.
Fired up the big old Rogers monitors and cranked up the volume and sod the neighbours.
Good to see the BBC taking the foot off the dynamic compression. Traditionally at this event and listening via FM, as the crowd start stamping on the wooden floor or the huge hall organ hits the low notes, the compressor starts pulling everything down.

Paul, do you fancy a bit of Land of Hope and Glory?

That or Jerusalem perhaps, the whole hall singing that was quite moving. Well at least combined with a few cans of guinness :)

I'll try the three new files in the morning.
 
Listened to Paul's three tracks.

Not keen on New C which had sloppy bass and sounded a bit messy IMO.

New D & E were pretty close but I had a slight preference for E.
 
From the BBC HD broadcast,

Jerusalem : http://www.mediafire.com/?r9re56gfnyu16m8

I'm not sure there's any point in uploading Pomp.

The path is Sky HD box recording replay, S/PDIF, a PC. So a digital dub. The rate is 48kHz. They only appear to transmit 14 significant bits, feel free to amplify, but this is what is sent. I think it is limited and compressed compared to the HQX, and there's nothing above 17kHz.

Paul
 
My notes indicate that,

C Squeezebox Receiver into DAC,.
D Squeezebox Receiver alone.
E HiFace into DAC.

One would expect C and E to sound the same.

Anyway I'm not particularly happy with any of them and will be returning to this.

And I'd like to understand the low resolution satellite (supposed) HD path. Perhaps I need a Dolby Digital decoder? Which is extremely limiting.

Paul
 
I thought E was considerably overblown, - could be described as nearly distorted in tonal response.
 

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