Go Back   Home > Forums > >
Home Forums Rules Articles diyAudio Store Blogs Gallery Wiki Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

Multi-Way Conventional loudspeakers with crossovers

Realistic Optimus 1B
Realistic Optimus 1B
Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 3rd October 2019, 07:58 AM   #1
PeteMcK is offline PeteMcK
diyAudio Member
 
Join Date: Feb 2002
Location: Western Sydney
Default Realistic Optimus 1B

Was donated a pair of these today, Crossover attached
The woofer (2519Aa Japan) looked promising with a low Fs & Qt, parameters:
Fs 20.75; Re 7; Qe .38; Qm 5.53; Qt .35; Vas 142.38; Sd 314; Le .84; eff 87.6
did some sims, Woofer looks good in 60L (Optimus oix is 38L), tuned to 22Hz
all this fun & I haven't listened to them yet....

The Big Q: Do I restore them to original, or 'improve' them to my own taste....???????

Bugger, just realised I left the tweeter switch out of the xover diagram, give me a few minuets....
Attached Images
File Type: jpg Optimus 1B xo.jpg (25.3 KB, 180 views)
File Type: gif Optimus 1B.gif (17.3 KB, 178 views)
__________________
Impedance varies with frequency, use impedance plots of your drivers and make crossover calculations using the actual impedance of the driver at the crossover frequency

Last edited by PeteMcK; 3rd October 2019 at 08:02 AM.
  Reply With Quote
Old 3rd October 2019, 08:07 AM   #2
PeteMcK is offline PeteMcK
diyAudio Member
 
Join Date: Feb 2002
Location: Western Sydney
OK , Xsim doesn't, appear to have switch Icons, so for 'Normal' it's 1.8 ohms after the xover, for 'low' it's 3.9+1.8 ohms in series, and for 'high, no resistors at all.
__________________
Impedance varies with frequency, use impedance plots of your drivers and make crossover calculations using the actual impedance of the driver at the crossover frequency
  Reply With Quote
Old 3rd October 2019, 06:30 PM   #3
Galu is offline Galu  Scotland
diyAudio Member
 
Join Date: Apr 2018
It does look like a promising proposition.

And here's a pic of those tweeter switches you mentioned!
Attached Images
File Type: jpg Optimus 1B.jpg (60.9 KB, 147 views)
File Type: jpg HF Compensation.jpg (204.6 KB, 148 views)
  Reply With Quote
Old 3rd October 2019, 06:40 PM   #4
Galu is offline Galu  Scotland
diyAudio Member
 
Join Date: Apr 2018
I just love investigating old speakers like these.

A pair of Optimus 1Bs cost $90 in 1975.

That's equivalent to $430 today!

Note: They are mid/tweeters, not simply tweeters.
Attached Images
File Type: jpg 1975 Price.jpg (106.5 KB, 140 views)

Last edited by Galu; 3rd October 2019 at 06:44 PM. Reason: Added the note.
  Reply With Quote
Old 3rd October 2019, 08:28 PM   #5
planet10 is offline planet10  Canada
frugal-phile(tm)
diyAudio Moderator
 
planet10's Avatar
 
Join Date: Oct 2001
Location: Victoria, BC, NA, Sol III
Realistic Optimus 1B
I have disassembled a number similar to these. I really like the woofer.

It should be noted that the identical looking mids and tweeter differ in at least the lable and this is wired as a 3-way system. Are you sure about the XO?

dave
__________________
community sites t-linespeakers.org, frugal-horn.com, frugal-phile.com ........ commercial site planet10-HiFi
p10-hifi forum here at diyA
  Reply With Quote
Old 3rd October 2019, 09:02 PM   #6
PeteMcK is offline PeteMcK
diyAudio Member
 
Join Date: Feb 2002
Location: Western Sydney
Dave, yes sure about the xover, I think it was the earlier Optimus 1 that was a 3 way.
I'll replace the caps & give them a listen later today
cheers
__________________
Impedance varies with frequency, use impedance plots of your drivers and make crossover calculations using the actual impedance of the driver at the crossover frequency
  Reply With Quote
Old 3rd October 2019, 09:14 PM   #7
Galu is offline Galu  Scotland
diyAudio Member
 
Join Date: Apr 2018
Optimus 1 also had two midrange/tweeters (16 ohm units in parallel).

Last edited by Galu; 3rd October 2019 at 09:23 PM.
  Reply With Quote
Old 4th October 2019, 12:18 AM   #8
PeteMcK is offline PeteMcK
diyAudio Member
 
Join Date: Feb 2002
Location: Western Sydney
FWIW, the original 'Contex' 15uF bipolars measured 17.3 & 16.4, not bad for ~50 years in the saddle.
Q&D RTA plot attached (taken in a small & cluttered room)
How do they sound? - Very well balanced, to my ear anyway, good on Jazz, and a surprising amount of solid lows on Rock, punchy kick drum. Don't know that they'd handle a lot of volume, but good medium-loud
Attached Images
File Type: png Optimus 1B RTA small.png (11.6 KB, 36 views)
__________________
Impedance varies with frequency, use impedance plots of your drivers and make crossover calculations using the actual impedance of the driver at the crossover frequency
  Reply With Quote
Old 4th October 2019, 01:14 AM   #9
sgrossklass is offline sgrossklass  Germany
diyAudio Member
 
Join Date: Nov 2004
Location: Germany
All I know is I wouldn't want to have my highs emanating from two drivers spaced this far apart - concepts like these disappeared for a reason after the 1970s. The peculiar ring around them presumably mitigates the effects of no flush mounting, but it also puts them pretty far apart. And why is the baffle so far recessed inside the cabinet?

EDIT: Highs +8/-10 dB? Oh my. Wouldn't be surprised if this changed a lot with vertical angle angle.

Honestly, this concept as designed is so far removed from modern standards of sound reproduction that I wouldn't want to simply restore these, assuming you actually want to listen to them on a regular basis.

Maybe find a suitable midrange and relegate one mid-tweeter to tweeter duties, assuming it's suitable for that? Do some impedance transformation with the crossover if needed.
Plan B, use mid-tweeters for midrange only and find a tweeter to go with them, it's not like there isn't any space left on the baffle.
Plan C, butcher the baffle and find good mids and highs to go with the existing woofer. (Maybe even a compression driver / horn affair? Seems wrong for an insensitive woofer like that though.)
Plan D, use the woofers for something else entirely (sub?) and come up with an all-new interior for the Realistics. (Pioneer sold relatively sensitive all-cone 3-way jobs for a long time, maybe find a set with 10" woofers but trashed cabinets?)

It would be pretty neat to turn these into a "sleeper" speaker - keep the neat veneered cabinet, keep the grille at least looking authentic, but bring the acoustic performance (mostly) up to modern standards, maybe even with a waveguide for the tweeter and all that good stuff. Seeing how you can't afford much in terms of XO losses with the woofer, possibly a candidate for activation as well?

That's some seriously low tuning and seriously low Q on those woofers. They look more like something for a sub assuming the Xlin is there. (Any estimates on power handling? I can't imagine they'll go super loud, maybe 100-105 dB assuming 20-60 W?) While this is not really a CB driver, I would consider whether potential speaker placement is actually suitable for a BR - would you put these on stands, far away from any solid surfaces, or alternatively, is the room sucking up bass like crazy?

Last edited by sgrossklass; 4th October 2019 at 01:21 AM.
  Reply With Quote
Old 4th October 2019, 01:38 AM   #10
Moondog55 is offline Moondog55  Australia
diyAudio Member
 
Moondog55's Avatar
 
Join Date: Jun 2007
Location: Norlane; Geelong: Victoria: Australia
If that is the little Fostex cone I rather liked it in past resurrections. I can think of several ways to "improve" them by adding in a supertweeter and some extra stuffing but for the time they were pretty good for most peoples listening. I have picked up several similar boxes over the years to play with. Usually pay about $30-
Willing to wager they sound better than the 3" plastic boxes most kids listen to these days
__________________
QUOTE" The more I know, the more I know, I know (insert maniacal laugh >here<) NOTHING"
  Reply With Quote

Reply


Realistic Optimus 1BHide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Realistic/Optimus Mach Two Tweeter nevdale Multi-Way 3 9th September 2008 04:14 PM
Realistic Optimus X-100 speakers Trebla Multi-Way 0 30th November 2006 12:05 PM
Realistic Optimus T-200 skanter Multi-Way 15 3rd October 2006 08:26 PM
WTB: REALISTIC MINIMUS/Optimus 7 Speakers mrdon Swap Meet 0 28th May 2006 10:39 AM


New To Site? Need Help?

All times are GMT. The time now is 06:56 PM.


Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2019 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 14.29%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2019 DragonByte Technologies Ltd.
Copyright ©1999-2019 diyAudio
Wiki