GRS 8PT-8 8″ Pro Woofer Review

GRS 8PT-8 Review

This 8″ GRS 8PT-8 is a budget woofer meant for pro use. As such, it is reviewed with this context in mind. Presently, she’s is loaded onto a 24 liters bass reflex but works equally well in a sealed box.

Fig 1 – GRS 8PT-8 Closed Box

Fig 1 is the Sealed Box modelling of the GRS 8PT-8. With a volume of 24 liters, the F3 is about 90Hz which is ideal for voice reinforcement. For music, a bass reflex can be used.

Fig 2 – GRS 8PT-8 Bass Reflex

Fig 2 is the box simulation of a 24 liters bass reflex GRS 8PT-8. In this version, the -3dB bass is at 55Hz. This is sufficient for most music. 

With this woofer, one can build a bass reflex box first. When voice reinforcement is needed, simply cover the port or stuff it with some cloth. This will convert the bass reflex to a closed box.

Fig 3 – GRS 8PT-8 RAW Frequency Response (no smoothing applied)

The Frequency Response of the GRS 8PT-8 is in Fig 3. This is with her mounted onto a 24 liters bass reflex tuned to 54Hz (Fig 2).

She does extend to 8kHz but the treble is pretty jagged. Good for a guitar speaker as the distortion will add some zing to the strings. Another use is for public announcements. 

Fig 4 – Dayton PA200-8 RAW Frequency Response (no smoothing applied)

For comparison, Fig 4 is the response of the Dayton PA200-8. Strangely, common to both woofers is the bump from 500Hz ~1kHz. It would have been perfect if it’s flat. Above 1kHz, the PA200-8 is flat to 3kHz after that, the breakup occurs. 

Due to the flatness from 1kHz to 3kHz, the PA200-8 can actually be used for HiFi but the bump from 500Hz ~1kHz must be flattened. When I auditioned her, I picked up the bump. It is particularly annoying in male vocals.

With the bump taken care of, a tweeter or a compression driver can be crossed as high as 3kHz. Personally, that’s too high for my taste. I prefer to cross at 2kHz~2.2kHz.

Fig 5 – GRS 8PT-8 ToneBurst Energy Storage

I included this plot to show how much excess energy is generated when the 8PT-8 is used as a Full Range woofer. This is not desirable in HiFi but is wonderful for a guitar speaker. If it is to be used in a 2-way, that is with a compression driver, one probably needs to use an EQ. It should not be an issue because it’s kind of standard to have a 31-band EQ in the setup.

Apart from PA, the 8PT-8 is suitable for bass duty in a 3-way HiFi system. Crossing at about 200Hz is about right.

If a 2-way is preferred, one can use a 3″~4″ wide band or full range woofer for the mids and highs. The 3″ Fountek FE85 is the ideal woofer. She has an incredible flat response and extends all the way to 20kHz. With this combination, you can get pretty decent music without costing too much.