B&C DH350 1" Compression Driver

[@ahnenpost5237]

very deep and well done review of this driver. I looked in your blog and found a zoom-in plot of the impedance, a small peak at about 9kHz and a (to me) corresponding one at presumemably exactly half the frequency at about 4.5 kHz - may be a resonance caused by a reflection from the horn mouth back into the compession chamber stopped at the diaphragm (kind of standing wave?). Can be seen in the burst decay as well. The difference in the samples preproduction vs no. 2 might be alike, a resonace between the diaphagm and the pole for example ... ideas .. here well damped vs not damped as good ..

[@greggb681]

I am so happy you posted this video, Troy! I have been considering using the DH350 for the 2kHz ES Circular Horns.

[@JosephCrowesDIYSpeakerBuilding]

Thanks!

[@FOH3663]

Very nice assessment. I appreciate the thought process of the "grossly mis-aligned" driver sanity check. Solid work, cool stuff.

[@sc0or]

It could be their phase plug ringing. And slightly different material makes the dip smaller.

[@rickg8015]

Thanks Joseph.. I hope you could do a review on the B&C DE550TN..

[@JosephCrowesDIYSpeakerBuilding]

What drew you to this driver? It would have be pretty good. No copper shorting ring.

[@benjaminlloyd7868]

Nice review

[@JosephCrowesDIYSpeakerBuilding]

Thanks!

[@318ishonk]

Thanks for sharing! I remember from other c. drivers that un-/remounting the rear cover sometimes led to a distorted sound (detected that with REW THD measurement). Now from your observations I wonder if it should be standard practice to always micro-adjust (optimize?) comp. drivers by running a THD measurment while assembling a driver and tightening screws...

[@ScottGrammer]

Decades ago, I was taught that whenever you disassemble a compression driver, you need to run a sine wave near the bottom of its range through it while adjusting the alignment and the tightness of the bolts holding it together, tuning for the purest-sounding tone. Typically, this involved perhaps 1mW of signal, and no horn.

[@318ishonk]

@@ScottGrammer Aah, there you go. Will run that procedure as well from now on.

[@gtvwill]

Makes sense, your dealing with highly sensitive volumes and pressure responses from the internal chamber/components of the driver. Torque and pattern of pressure when done up would be pretty important you'd assume. Much like a engine block if you do the bolts up in the wrong pattern let alone to the wrong torques your pressures to gaskets providing the seals between components won't be correct/balanced/even. Wonder if he used a calibrated torque wrench in re assembly or if he just raw dogged it? Few dugga dugs from an impact driver an it'll be right? Lol. Someone should do a video on it.