I want a cost effective passive 3-way xover to mate GRS 12PT to GRS 6PT plus "whatever" tweeter

I wish GRS would produce an LE20/LE25 clone for a reasonable price (35-40 tops) - I remember my L26 from 50+years ago and its 'sound" $75 for a clone (how really close?) seems steep for the materials and size involved.

here's a pig n a poke

one thing I noticed while playing with several clones of the old CTS "Phenolic Ring Tweeter" was that they were unable to reproduce any semblance of a cymbal crashh -- Faital's 3FE35 fared better (might take four of them per side)

Last edited:
THAT LOOKS GOOD - I'm sure my blood sugar is way high - FWIW I took the large file and upscaled it to read a day ago - wrote down the schematic and will order some coils, caps and whichever tweeter looks best for low dough.

I can barely type - wracked with tendon pain in both arms from fingers to worn out frozen shoulders - neck position triggers the awful pain too -

IF I bungle this thing it might be a LR100 ("low rent"...)
Looked at the GRS 6 and 12 pt.

I like the drivers for having copper Faraday rings on the pole piece!

I would build a speaker with their 18inch candidate one day...


  • 292-806_ALT_1.jpg
    395.2 KB · Views: 10
  • 292-806_ALT_2.jpg
    298.2 KB · Views: 16
  • grs-6pt-8-midbass-tieftoener.jpg
    18 KB · Views: 12
  • grs-6pt-8-midbass-tieftoener(2).jpg
    24.8 KB · Views: 11
  • Like
Reactions: 1 user
@WhiteDragon - what volumn did you use for 6PT's chamber? It might be awhile for a cabinet but started on an xover. Maybe I can run just a baffle with proper driver locations to get a feel of things.
6PT has enough sensitivity
But has tradeoff of High Qts to do its thing.
Unfortunately requires a somewhat large volume.

But I do run some drivers on the small side for midrange.
But 1.3 liters would be pretty high Qtc

Typically I like to run .8 to .9 max Qtc for a mid
But would run the 6PT pretty close to its Vas.

Basically getting close to 1.00 Qtc
But for the form factor of this 3 way
1.1 Qtc is 6 liters

Use 9 liters to 6 liters minimum

And 3 liters would be way to small
so 1.3 liters again is way to much Q

in sim need to use filter to judge xmax
the crossover used will keep it way under
xmax at 6 liters

in the screen shot I show 3 liters
in pink and its painful to look at.
and adds to much Q
dont want Q touching the crossover set around 500 ish
Linear excursion for a midrange
in the 4mm range is rather healthy.

With the right crossover
or just a basic high pass really

Excursion will be under 1mm
And with full thermal power.

100 watts put you close to 112 dB
think the cops will come before the
speaker goes.

Here is cone excursion at 100 watts in
yellow. NO crossover.

With crossover the speaker is under 1mm
and you will exceed the thermal rating
way before you hit linear limit.

PINK line is with basic 2nd order as used
in the crossover.
6 liter box is enough to keep Q out of the passband
and Xmax never exceeded at full thermal power.

one thing I noticed while playing with several clones of the old CTS "Phenolic Ring Tweeter" was that they were unable to reproduce any semblance of a cymbal crashh
Yes pretty much.

Ironic with measurement of paper / phenolic tweeters
most would assume they are "harsh"

My pioneers were on a simple 1st order
and the paper was never harsh.
And exactly just lacked detail.

Roger Sound labs 3600
had a dome tweeter.
Something a basic dayton Silk would do.
Now days.
Dayton silk like the DC28F shown.
Isnt harsh on very very high crossover.
It wont cross low enough to the 6PT
my opinion.

Main issue with ceramic tweeters.
Is the magnet size.
Makes center to center spacing non ideal.
Just like the Roger Sound labs.
Sound quality is ok, in measurement
vertical actually even horizontal.
Wont be as great with RSL because tweeter
is way way to far out.

JBL did better spacing with the phenolic.
Its the physical size that cant be beat.

Wish I could sell you on the Neo titanium.
Not only is the extreme detail there.
The neo magnet makes center to center
tight tight tight and wonderful.
And the vertical still has its dip off axis.
But it is tighter than many many systems
of higher cost.
With 4th order vertical can become little dreamy.
Just a midrange 4th order to match it.
Is not as budget.

Im doing a 2 way soon with the paper tweets
just because I have a thing for strange 2 ways.
and the phenolic tweets.
4th order.
The GRS sounds better than most assume.
better than " wideband" top end
and plenty people running 3" speakers
wide open these days.