GRS PT6825-8 Planar Test Results (300Hz Horn)

[Joseph Crowe]

I’m sharing my test results of the GRS PT6825-8 planar in a front horn. This driver responds well to horn loading providing low distortion down to 300Hz. IMD is -55dB even at 100dB SPL 1m. It’s nice to see an affordable replacement to the NEO8 become available.

Specification Sheet

 

[CharlieLaub]

You do great work with custom horns, lovely stuff, and high performance too. I would love to see a two-sided (e.g. dipole) horn setup for the GRS PT5010 that would also extend and improve the low frequency performance. It should be relatively easy to make a dipole horn with this kind of "flat" driver - just mirror the horn to the rear. Any chance you would give that a try?

 

[unaHm]

I’m sharing my test results of the GRS PT6825-8 planar in a front horn. This driver responds well to horn loading providing low distortion down to 300Hz. IMD is -55dB even at 100dB SPL 1m. It’s nice to see an affordable replacement to the NEO8 become available.

Specification Sheet

Thanks for sharing your results Joseph! It's very encouraging, especially because it loads well in a horn. This might be what I've been looking for

 

[Joseph Crowe]

You do great work with custom horns, lovely stuff, and high performance too. I would love to see a two-sided (e.g. dipole) horn setup for the GRS PT5010 that would also extend and improve the low frequency performance. It should be relatively easy to make a dipole horn with this kind of "flat" driver - just mirror the horn to the rear. Any chance you would give that a try?

I’ve not done too much with dipole. The rear chamber is optimized to really lower distortion near the cutoff Frequency of the horn (nearly -10dB lower noise floor).

 

[Studley]

Can you post a pic of the horn you have used with this driver please.

 

[Joseph Crowe]

Can you post a pic of the horn you have used with this driver please.

 

[Bryguy]

Absolutely gorgeous! Where did you cross these over? If anywhere near the 300Hz point you mentioned you basically have a WAW on your hands!

Would be interested to hear your subjective impressions. This is not too far from a design I have been fiddling around with, although with a modicum of your expertise!

 

[unaHm]

I can confirm that they work really well. I used a horn design based on Bill Waslo's spreadsheet calculations, and stretched the horn dimensions to accommodate the planar transducer. The drivers themselves are very accurate, and loaded into the horn sound like headphones down to about 400Hz!