[aroon]

Quote:

Originally Posted by John Reeves Hi, You are probably aware that as people age their sensitivity to high frequencies deteriorates. In order to ensure that this is not a critical factor, which affects your results, you will need to carry out an audiogram test on each subject. You can probably get a source for this and carry out the tests yourself. [...] Best of luck and looking forward to "hearing" your experiences....pun, LOL. Cheers John

you're right. thanks for bringing that to my attention. i had worried about that before but i didnt give it much serious thought. by far the majority of my subjects will be between 18 and 25. im not sure i want to go through the trouble of having each subject actually tested but its definately a good idea to make sure they can actually hear before doing the experiment. i know hearing is often checked by doctors by playing different frequency tones in each ear and having the patient raise the according hand to indicate that they did hear the noise. i think if i did that for each subject to make sure they pass the test then that should be enough. and if they fail then i guess ill have to discard them from the test.

in anycase, im not looking for perfect hearing, i need average so ill have to do some research on that too!

 

[JazzJackRabbit]

aroon
A couple of pointers, maybe that'll help you.
1.If you are planning to buy an entirely new mp3 portable, I think it would be better to go with creative zen xtra, AFAIK it has better signal output than ipod.
2.Unless you are going to do all your testing in a quiet isolated room, you better buy closed phones. Open ones like Sennheiser 580/600/650 let EVERYTHING in, not surprisingly that I find them most enjoyable only at night. If you have to go with closed headphones A-T A900 and Sony CD3000 should be easily driven by portables and provide enough detail for your experiment.
3.However most of all, I would strongly suggest you abandon the portable idea and use your PC/Laptop for testing. The main reason is that using your OC/Laptop with Foobar you can do a A/B comparison between two identical tracks with different bitrates. It's really hard for unexperienced individual to discern between two bitrates while listening to tracks sequestially. With foobar you should be able to do a blind A/B conparison which IMO would give you the most accurate results.

 

[aroon]

Quote:

Originally Posted by JazzJackRabbit aroon A couple of pointers, maybe that'll help you. 1.If you are planning to buy an entirely new mp3 portable, I think it would be better to go with creative zen xtra, AFAIK it has better signal output than ipod. 2.Unless you are going to do all your testing in a quiet isolated room, you better buy closed phones. Open ones like Sennheiser 580/600/650 let EVERYTHING in, not surprisingly that I find them most enjoyable only at night. If you have to go with closed headphones A-T A900 and Sony CD3000 should be easily driven by portables and provide enough detail for your experiment. 3.However most of all, I would strongly suggest you abandon the portable idea and use your PC/Laptop for testing. The main reason is that using your OC/Laptop with Foobar you can do a A/B comparison between two identical tracks with different bitrates. It's really hard for unexperienced individual to discern between two bitrates while listening to tracks sequestially. With foobar you should be able to do a blind A/B conparison which IMO would give you the most accurate results.

interesting...

thanks for the pointers. i didnt know about this ability in foobar. ill be honest though, one of my reasons for using a portable set up is because we get to keep the equipment we purchase using our funding ; )

but you're right. in the end, if a laptop works better we'll find a way to use it. after all im not going to get funding if i cant get results in the first place!

as for the headphones, my intention is to use an isolated and quiet environment, however, in the case that i can't manage to reserve a room ill keep in mind that i need closed cans. thanks!

 

[halcyon]

If you are interested in having accurate results, consult the following links:

http://ff123.net/
http://www.kikeg.arrakis.es/winabx/
http://www.hydrogenaudio.org/index.php?showtopic=22189&

Headphone will be the smallest concern you should be looking at. Not to say it isn't important, but proper test setup is much more important for good results.

best of luck with your test!

 

[Kuja]

I believe that the membership of HA consider it basically settled that the overwhelming majority cannot perceive a difference between codecs and bitrates at 192kbps and above.

Therefore, unless you are doing it for uni or whatever, you're only rediscovering the wheel.

Of course, give that the vast majority of music sales are comprised of repetitive, formulaic music with no dynamic range, poor mastering and so on, played on cheap systems or in 128kbps mp3 form, it would seem that the general public is highly unlikely to see a difference, even if one really does exist (as opposed to some of the more subjective and debatable assessments of quality that are made here and on other enthusiast sites

).