+ Reply to Thread
Results 1 to 3 of 3

Thread: A comparitive test for difficult evaluations of kit.

  1. #1
    Join Date: Aug 2008

    Location: notts uk

    Posts: 295
    I'm Pete.

    Default A comparitive test for difficult evaluations of kit.

    Well that's a mouthful ...

    I was asked if I could look at fuses to see if there was any milage in swapping them. Not necessarily for expensive hifi types but just the standard ones. After listening to a number by various makers Bussmann SEM Marbo Vernon Harbo etc .....It was apparent that my system was capable of sounding different with each fuse ...but quantifying the difference was very difficult. This got me thinking how can I present what I'm hearing in a manner that I can compare them side by side.

    After much experimentation the current version of my comparative test uses the following ....
    A pink noise source [berhinger 2496 feeding pink noise via a digital output to mr digital hub ..quad artera play]
    a tripod
    mobile smart phone[samsung a70]
    spectroid app

    With everything set up it's then just a matter of playing the pink noise at a set vol [on both pre amp and behringer 2496] recording it on the smart phone set on the tripod and taking a screen capture. Then changing the item under investigation and repeating.


    I'm not claim this is definitive or the last word in testing ...but its quick easy and most people could do it !

    critical observations ...
    the failings of the smart phone mic and processing software , I thought long and hard about this and then I realised that if for instance a section of the freqency spectrum was not being cover properly ...it would of course be equally not covered for each test. So the deficiencies and short comings of the test equipment can effectively be ignored as long as this is comparative analysis.

    the results are presented as screen shot off the phone .....from the very first test of the methodology it was obvious and consistent that the phone was able to pick up small sound differences. I originally carried out 20 or 30 samples of the same recorded musical passage....but it was very hard to get the screen shot of the same moment hence switching to pink noise that was consistent over the required time period [30 sec or so].

    Below are some of the results

    firstly the screen shots and then the comparative shots where I've compared the images.

    As you can see each of the fuses in this instance have there own signature ...but what this doesn't do is show which is best just that they are different.

    In conclusion I've now used this method on a number of components and as long as all the parameters remain the same results are consistant between test items.

    Note the colour difference seen in the bussmann trace is wholly due to my image processing and loosing the original ! I had considered making that image greyscale but that actually looked too different.

    As I've only a small brain so suggestions to improve the methodology would be welcomed .....!

    I have considered stacking similar trace images and have downloaded the software but not actually got round to using it to see if it reinforces the results.







    bussmann).jpgalpha2000.jpgthreefusestrace.jpgfusetraceb.jpg

  2. #2
    Join Date: Apr 2012

    Location: Southall, West London

    Posts: 51,621
    I'm Geoff.

    Default

    I can't see if you actually mentioned where the fuses were being employed. Mains, signal, circuit protection etc?
    It is impossible for anything digital to sound analogue, because it isn't analogue!

  3. #3
    Join Date: Aug 2009

    Location: Staffordshire, England

    Posts: 37,737
    I'm Martin.

    Default

    How many samples of each one did you do?

    I'd have thought that variations in background noise would swamp any minor changes caused by the fuse? Or am I missing something? Obviously if the variation is consistent over many samples you might be onto something. Interesting experiment.
    Current Lash Up:

    TEAC VRDS 701T > Sony TAE1000ESD > Krell KSA50S > JM Labs Focal Electra 926.

+ Reply to Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •