GRS 6PT-8 6-1/2″ Pro Midbass Thiele/Small


The GRS 6PT-8 is a 6-1/2″ midbass driver for pro use. I bought this unit primarily for the midrange. I was thinking whether it’ll be suitable for a small MTM with a horn in between. That will give a nice projection in the vocals.

Manufacturer’s Specs
GRS 6PT-8 Thiele & Small Parameters (DATS)

My DATS measurements are disappointing. Instead of a Qts of 0.72 as stated in the manufacturer’s specs, my unit is at a horrific 0.93. So what size of enclosure am I expecting?

Sealed Box=25 liters | F3=100Hz | Q=1.0

As I feared, a 25 liters sealed box resulted in a Q of 1.0. This is about the highest Q that I can accept. F3 is not an issue at 98Hz. This is fine for vocal use but I’m unhappy with the high Q.

Ported Box=27 liters | F3=83Hz | Q=1.0

I faced this high Q issue with the Tang Band W6-789E. I honestly don’t know whether it will work with the same box that I used for the Flamingo-TBFC but it’s worth a try. This GRS 6PT-8 may end up as a speaker for HiFi rather than for pro use.