Compression drivers Part II (News)

by Bert , Wednesday, February 22, 2006, 21:35 (6645 days ago)

Hi all,

I finally received the first prototype Oris 250 for compression drivers!

The first thing I did was measure the low end response to see if my theory works out in practise. Guess what, it does!

Without doing any power tests and based on primarely measurements the Oris 250/2C loads the BMS 4592ND midrange all the way down to 250Hz including a simple 12dB high-pass filter (below that it drops like a rock, as expected). The impedance having one pretty strong peak at resonance (350Hz, when not loaded) became pretty well dampened with the horn in place, only three relative small peaks were left and another strong impedance peak at 1000Hz (unloaded) dissapeared after connecting the driver to the Oris 250/2C horn. Great so far...

The tweeter extends very well up to 22kHz and does not drop too fast when measuring off-axis (at 10 degrees still pretty okay) but the crossover range didn't look too good to me...

Okay, time to listen to some music using the standard filter provided with the BMS driver.

Very dissapointing, this sounds like a horn as used on football fields!

Next day:

I made a good adapter which already sounded better but still not good enough... Searching for the problem(s) causing this I'll started to work on the midrange only, removed the BMS low-pass filter and listened without the tweeter part of this coaxial compression driver.

Much better! Gone was most of the nasal and aNoying character, this starts to make some music!

Up to date: Very promising but not yet good enough. I'll need to make my own filter and do many more experiments to see if I can make the BMS sing full-range in the future Oris 250/2C horns.

I'll keep you'll posted...

Bert

--
BD-Design - Only the Best!

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