On creating random corrugations to ribbon microphones

It has been tried successfully when re ribboning 2 Grampian 25-50 ohm ribbon microphones. The ones with the grey grill and black grill on the other side. Grampian made in England model GR1/L output impedance 25/50 Ω.


The random corrugations were done by zig zag folding by hand the ribbon sandwiched by its 2 protective papers. And if memory is correct, then it was cut to the long thin ribbon stripe by placing it flat. Breathing was done with folded straw as the extremely light ribbon had the tendency to fly.


Listening now to the recording done before 2000 it seems to blow away anything?


Signal path, setup:


Untreated living room - Gabriel Drums, WLM Organ with Pleiades PCL86 SE class A1 and Pleiades ceiling hung rotating speaker, Yamaha bass guitar with Doublex amplifier and ?4x 8Ω full range speakers mounted on an open panel baffle? - 2 x Grampian GR1/L as Blumlein pair - Sowter 1:20 3104x stepup transformer - Ferrograph series 6 (valve) electron tube reel to reel tape recorder with 1/4 track heads before changing to 2 track stereo heads - BASF 901 studio master 1/4in tape - Tape reproduced from UHER battery powered 4200 stereo with one channel operating - (either to Realistic disco mixer - Sennheiser HD580 or direct to SONY APM-078 speaker)


Sound can be heard coming from both sides of the tape as the UHER is 1/2 track, so one can hear 2 musical pieces at the same time one being in reverse. Interesting sound real and out of this world at the same time, a joy to hear simultaneous cymbals in both time directions at 7.5ips and -7.5ips. The bass definition, warmth, detail, midrange smoothness of the organ, creamy super extended treble of the cymbals is hard to believe.


But it is no wander. It is just 3 electron tubes from the Grampian ribbon mics to the BASF 911 studio master tape.


Speed is 7.5ips.


The musical,piece played is the brilliant Supertwister - Camel with the G7, A7, B7 chord progression.   Since the scale is G Dorian where the B is B flat, it follows that the chords are the brilliant G minor 7th, A 7th, Bb major 7th.


The Grampian mics, the instruments around them, gave an excellent frequency spectrum balance at the relatively high distance from each instrument. It seems the mics are proximity compensated with their internal transformer input inductance exactly for such applications.


Blumlein recording of rock music is possible and if the room was treated with broad band panel absorbers such as the Pleiades absorbers the sound should have been even more direct.