Griffin "27" Omega 3 Loudspeakers - Opinions?

[izools]

Deaks50 - that's amazing to find someone who probably originally built these speakers just on the off chance! Good work by the way

Planet10 - yes that's a B200 SP1014

I'll take a close up pic tomorrow - the red bits are the cones themselves - you'll see (hopefully) in the close ups

It is a resistive port next to the Coles yes, but as Deaks50 sais the term aperiodic reffers to the design of the crossover which passively filters the peaks and troughs in the impedance graph; so as to create a more linear and consistent impedance of the speakers accross the frequency range.

I'll post up a copy of the original datasheet too... tomorrow

[deaks50]

Hi
No Aperiodic refers to the design of crossover.
The port was a standard tuned reflex system covered with foam.

[deaks50]

Hi
The coles was a lower cost production option in the late 70`s, the red ring you can see was just a cosmetic feature of the cone.
The mid range driver was a Kef unit with the outer securing ring removed (it was used to secure the foam covering the reflex port)
Paul designed the speakers to be neutral in response across the range, as he disliked speakers that had a characteristic "sound".
Perhaps this explains the apparent lack of bass?

[deaks50]

Hi
A high quality mike positioned directly in front of the cone/dome was used to map high spots in the frequency response of the driver, which were then filtered out passively in the crossover.
It was an idea inspired by the tri amplified Griffin 85 speakers with electronic crossovers and "tandem line" actively braked bass
system (a fantastic speaker-and very advanced for it`s time).

[planet10]

Originally posted by deaks50
It was an idea inspired by the tri amplified Griffin 85 speakers with electronic crossovers and "tandem line" actively braked bass ystem (a fantastic speaker-and very advanced for it`s time).

Thanks for all the info... can you tell us more about this one?

dave

[deaks50]

Hi
The 85 tandem line base system (patented) was basicaly a Kef B139 unit in a sealed box, "air braked" by a reverse-phased Kef B200 unit fixed into the top of the box, with a pot used to vary the damping of the bass.
The power amps (3-total around 150 watts rms) were fitted into the back of the speaker. There were three active crossovers and three pots to vary the output levels. Pre amp was remote.
The cabinets were constructed in high density chipboard and mounted on an S shaped steel stand to isolate the speaker.
Thirty odd years later I`ve still yet to hear a better speaker (although my ears are shot compaired with the day!).

[planet10]

Originally posted by deaks50
The 85 tandem line base system (patented) was basicaly a Kef B139 unit in a sealed box, "air braked" by a reverse-phased Kef B200 unit fixed into the top of the box, with a pot used to vary the damping of the bass.

This is very interesting. Do you have a patent number?

Somewhat similar is the idea of adding an R to a second voice coil on a woofer, and an idea i had for an isobarik with the rear driver driven by another amplifier controlled by a DSP.

What mid & top did they use? Any pictures?

dave

[deaks50]

Hi
I`m afraid not.
However, I believe that Linn also patented a similar system in the 70`s. The bass system was unbelievably simple - genius in fact.
The 85 used twin STC super tweeters, a large single KEF mid range driver and a KEF B139 bass driver.

[izools]

Hi guys! Re: pictures camera batteries dead I'm afraid.

They're on charge at the mo, just gotta do the mother's day honours (Whetherspoons... about £4 a head per course! :P ) and when I come back batteries should be charged & I'll post some more pics.

I'll try to get a pic or two of the crossover, too. I've not seen it yet but should be interesting from sounds of things!

[deaks50]

Hi
The crossover is fixed to the bottom of the cabinet, behind the base unit, covered by accoustic wool.