Thanks for the pointers on fabric testing
One thing that I found was that a slightly better version of breathe through test is to just try to talk while the fabric is very close to mouth and either listen for yourself or have someone stand in front and listen for changes in voice quality. This gives a good indication of sound transparency atleast in the vocal zone.
Quick impressions on samples below for sound transparency (unscientific) Rating the sound transparency as high, medium, low.
- Low - 10Oz Cotton, Cotton Twill, Linen Cotton, Microsuede, Poly Duck, Fleece, Cotton Sateen, Satin
- Medium - 4Oz Cotton, 6Oz Cotton, 7Oz Cotton, 10Oz Cotton, Yoga Jersey Knit, Lycra
- High - Polyester Poplin, Poly Diamond Knit, Poly Jersey Knit, Spandex Knit, Cotton Lycra, Viole, Crepe de Chine
Out of the high sound transparency fabrics: Viole, Cotton Lycra, Crepe de Chine are very thin or have poor print quality so I would exclude those.
That leaves Polyester Poplin, Poly Diamond Knit, Poly Jersey Knit, Spandex Knit.
Polyester Poplin - seem to be quite good if you want a non stretch material
Poly Jersey Knit - slight stretch but the colors don't pop.
Spandex Knit -the most sound transparent of all, slight stretch, some black crush. I am leaning towards this.
- Best non stretch material - Polyester Poplin
- Best material with some stretch - Diamond Knit and Spandex Knit. Diamond Knit probably has slight edge in print quality and spandex knit edge in breathability.
I am leaning towards spandex knit. I called the customer service about the slight lack of detail and they mentioned that it might be a specific sample issue. According to them the print quality for that material should be as good as other fabrics.
Will probably order some posters in spandex knit.