Category: Audio

Why tube amplifiers sound better than solid-state ones

Yes, yes, to be more precise I should’ve said: “Why tube amps sound different than solid-state ones”, but I used the word “better”, because lots of audiophiles prefer the tube (or tube-like) “euphonic” sound 😉 One of the usual explanations is even vs odd harmonics, but still it’s not clear why we prefer even harmonics.

These two excerpts make it clear:

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UPnP devices do not see each other

If UPnP devices do not see each other, most likely there are two problems:

Multicasts are not forwarded

Simple Service Discovery Protocol (SSDP) uses multicast IPv4 address 239.255.255.250. The local switches must be able to forward such traffic. On a Cisco switch you run the following command to allow that:

no ip igmp snooping vlan 101

Firewall blocks UPnP traffic

Related ports: UDP-1900 and TCP-2869

Universality vs Simplicity or PSAudio and The Bridge woes

In my mind universality and simplicity are mutually exclusive. I’m yet to find a system which is universal and simple to configure and use. Reliability and stability are assumed by default.

The simplicity of Apple devices is addictive. You add a new box and it gets automatically recognized. Everything just works like prescribed and defined by Apple. Then it’s a question of if this Procrustean bed fits you or not and if you are flexible enough to assume the offered model.

The idea of service/device discovery appeared in the late 90’s. For example, Sun’s Jini (1998) and UPnP (1999). It’s nice to have a standard to allow devices from different vendors work together, right? Sure, but here comes the reality. The Cisco interpretation of the Spanning Tree Protocol is different from the Foundry (now Brocade) one. If you place Cisco and Foundry switches/load balancers in one LAN, you may end up with a funny STP loop.

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Live vs conserved music or Lugansky vs Residentie Orkest
or Rachmaninoff and Socionics

We’ve just returned from this concert in The Hague:

Elgar, Enigma-variations Xian Zhang, conductor
Sergey Rachmaninov, Piano concert nr. 3 Nikolay Lugansky, piano, Xian Zhang, conductor.

Residentie Orkest The Hague Philharmonic

Mixed feelings and a helluva thoughts (Yeah, as always). OK, one by one…
Continue reading “Live vs conserved music or Lugansky vs Residentie Orkest
or Rachmaninoff and Socionics”

How to downmix 4 channels into 2

Or a quadraphonic record into a stereo one.

Le’s assume you have a bunch of files in one directory. The following script will downmix 4 channels into 2 with the following proportions:

  • LF => 100% LF
  • RF => 100% RF
  • LB => 100% LF
  • RB => 100% RF

and move the stereo files into a directory called “stereo”:

mkdir stereo
for file in $*
do
  sox -S -c4 "$file" -c2 stereo/"$file" mixer  1,1
done

If you want to change the front/back ratio to, for example:

  • LF => 100% LF
  • RF => 100% RF
  • LB => 70% LF
  • RB => 70% RF

the sox command will look like:

sox -S -c4 "$file" -c2 stereo/"$file" mixer  1,0.7

Upgrade x (Solaris + SqueezeCenter)

Here’s a quick way to upgrade one or both Solaris (tested with Nevada snv_107) and SqueezeCenter (tested with SC 7.4 24827).

  1. Remove the CPAN directory in the SC root directory
    # mv CPAN CPAN.orig
  2. Install missing CPAN modules
    # perl -MCPAN -e shell
    cpan> install Bundle::CPAN
    . . .
    cpan> reload CPAN
    cpan> install I18N::LangTags
    cpan> force install Scalar::Util
  3. Disable Encode::Detect::Detector module in Slim/Utils/Unicode.pm (line 40). The module can’t be compiled for Solaris.
    # vi Slim/Utils/Unicode.pm
    . . .
    #use Encode::Detect::Detector;