[Bumpy]

I've spent a happy afternoon using REW with UMIK-1 to investigate things.

I found it beneficial to reverse polarity on the bass driver alone to integrate it better with the midrange driver. I achieved this by reversing the wiring on the rear terminals. BUT the inductors are now on the negative wire rather than the positive. IS this OK?

Also my inductors have red and black output wires, Are they truly directional and if I have now reversed polarity should they be reversed as well?

I appreciate this is all pretty standard stuff to many of you, but please bare with me.

[Jeff]

I'm not sure I'm helping at all as you do not answer...  I deleted my suggestions on reversing the mid or woofer because I did not want to lead you...in this infinite monkey

The inductor is not polarized, but the OD would tend to be input if used in series.  It will be fine connected to the negative input, but you may consider moving it to the other leg if you end up with a shunt cap in the bandpass (mid).

[Bumpy]

Thanks again Jeff. Believe me I do read and appreciate all the replies made here and I try my best to apply them. )

[Bumpy]

When switching from a single pole to a two pole mid LP, you should also consider the tweeter cap value.  The issue that you site, is it better, worse, or the same when the tweeter is connected?

Having Tinnitus (years of riding a noisy Harley) is a real challenge. Firstly one can have no idea what specific frequency triggers it, though in my case high frequencies are suspected. Secondly its also a phycological response so just concentrating hard to analyse sound triggers it, and sometimes just remembering you have tinnitus triggers it!

Nonetheless I have the option of four suitable tweeters namely Siemens, Grundig (small and big) and Saba Greencones. All are vintage paper cone, alnico magnets so both tonally and in sensitivity they are well matched to the other two drivers.

My choice ATM is the Saba Greencone it is the smoothest and less likely to trigger the Tinnitus.

[Jeff]

Completely understood.  Even before we consider that many other people also suffer tinnitus (about 20% of adults including me), or that I've been engaged in audio for more than 40 years (professionally for over 30 years).  The part I'm missing is, "is it better, worse, or the same when the tweeter is connected"  You mentioned somewhere in this thread that it was easy to connect each driver separately in the current setup.

Now, you are looking at a different tweeter before further fleshing out the XO?  I'd would have assumed you would have selected the best candidate before starting...

[Bumpy]

[quote author=Jeff link=topic=161048.msg1855466#msg1855466 date=1619293022

Now, you are looking at a different tweeter before further fleshing out the XO?  I'd would have assumed you would have selected the best candidate before starting...
[/quote]

Correct,  I had all these tweeters in place during my early evaluation and each was listened to for extended periods as single drivers. The Siemens (biggest magnet) was the most dynamic and full of life, and the Saba was the smoothest overall (smallest magnet) and showed up best as a flat response on REW.  I do realise that magnet size does not always correlate with 'performance' and that these vintage driers extend nowhere near the upper reaches of modern tweeters. But they are open backed, which of course is a bonus for OBs

I had originally chosen the Siemens for its sense of realism, but it demonstrates that interactions with the mid range and crossovers also have a big bearing in overall SQ.

[Bumpy]

I want to add a second inductor to lower the upper crossover point of the midrange low pass filter.

I will buy the same same brand of inductor to match that already fitted i.e. Jantzen Cross Coil, Copper foil Inductor 47mm width, 12AWG.

Just to confirm that the two inductors are wired in series.