JBL PTB99HF-1 Waveguide

[DualTriode]

I searched the diyAudio site for any reference to the 1 inch screw on JBL PTB99HF-1 Waveguide. 6 inches square. 90 x 90 degrees.

I came up empty.

Anyone use it in a project. Listen to it or have anything to say.

I am thinking of possibly applying it as the top end in a bookshelf.

I have a pair plus a pair of JBL 2408H-2 compression drivers to test drive.

I will post some measurements if there is an interest.

Thanks DT

 

[DualTriode]

Hello,

Using the AP tools on my bench I measured the PTBHF99-1, JBL2408H-2. This is what I got for impedance, phase and TS/P. More measurements to follow.

I did not see any wild resonance stuff in the higher frequencies, good news. Sometimes there is breakup that shows up as high frequency resonance.

Note: these are raw data curves. The saw-tooth appearance happens with Compression Drivers and Waveguides/Horns. My suspicion is that some of the output bonces around on the hard surfaces on the longer reflected path out of the waveguide.





Disclaimer:
I am a retired ME. I own more electronic tools than I should. I measure stuff for fun. If I claim to measure or hear stuff, Your Mileage May Vary.

 

[DualTriode]

See the attached PTBHF99-1 on JBL2408H-2 plots, typical waveguide/horn roll-off that will require some EQ plus some padding.

If I recall the input voltage was0.5 volts The microphone was ~ 5 inches from the plane of the waveguide flange.

loud output.

low distortion.

Perhaps crossover at 2.5kHz or higher.

Thanks DT

 

[norman bates]

looks good though