equalizing networks on Lowther

[audio3]

Hi guys, does anyone have experience with equalizing networks on Lowther? I read Nelson Pass's article "Current Source Amplifiers and Sensitive Full Range Drivers".

I would love to get some feedback and advice.

Good music!

 

[wchang]

Do you already have drivers/cabs? Many degrees of freedom. I double-notched my 15ohm non-silver-coil PM6A.
https://www.diyaudio.com/community/...ile-city-of-22m-laid-flat.393338/post-7266571

 

[audio3]

Hi, yes I already have Lowther EX4 8ohm on tp1 cabinet (double horn loading)... On some musical passages the high frequencies are very evident...

 

[wchang]

MJK has measured the DX 8" drivers, especially DX4 on-axis 10dB bulge 6-12khz (his reading) or 7-14khz (my reading of his chart) which went away 30deg off-axis. If this is what you hear, a simple notch filter centered at either 8khz (the peak) or 10khz (the broader plateau) ought to bring relief.

http://www.quarter-wave.com/Project04/Measurements.html (MJK meas. Lowther DX Series)

You might try connecting a notch filter to driver+ (and if a trough is heard then add a parallel resistor)
8khz peak: 0.39mH || 1uF
9khz shallow: 0.3mH || 1uF
10khz plateau: 0.36mH || 0.68uF || possibly 10-15ohm

Notch center frequency ~ 5khz/sqrt(mH*uF) but
depth and breadth depend on actual impedance curve.

 

[GM]

Typically use a band pass filter.

 

[Nelson Pass]

The store has a cheap full range EQ circuit that was largely developed around Lowthers and similar drivers.

 

[audio3]

Thank you Mr. Pass.
Does this circuit need to be placed between source and amplifier?

 

[Skip Pack]

I'm using one of Nelson's full range EQ active filters between my dac and preamp (could go after the preamp also). It is way better than previous passive solutions I have used and is very flexible. My system is using Alpair 11MS drivers in small Nostromo cabs. The bass/low mid is perhaps a tiny bit much, but tunable with a resistor change, the upper mid/high cut is widely adjustable with the pot and optimizes nicely. Check out the article attached here: https://www.diyaudio.com/community/threads/full-range-eq.399413/

Skip

 

[audio3]

Tanks!

 

[audio3]

I just purchased the equalization board from diyaudiostore.
I can't wait to try!
Thanks for your advice!