Kinda high w/o the EQ. Maybe Nelsons FR EQ board would be a good place to start when diying one.
But sometime sit is easier just to start over.
And probably worth mentioning an East German loudspeaker, can’t recall the name at the moment, that had 8 front firing 4-5” FR (w whizzers) in the same arrangement as the (pro) 901.
dave
Didn’t I see something like that at your place? Was it Telefunken, Isophon or ?
I have two pairs of Acoustic Energy AE1 and I used to have (sold one... ) a pair of ARC D70-II amps.
So, I set it them up on 24" Target speaker stands. The bottom speaker was normal. The top speaker was upside down and I could aim it straight ahead or backwards. The stands were about four feet from the back wall. I could also play with the phase of the top speaker, so I could make the system into a dipole or bipole.
It had almost no WAF factor. In fact, bywired with Nordost Cables is looked pretty ugly. But it was fun and taught me a lot.
After that, I got into Maggies.
Telefunken was West German. We had a Telefunken multi band radio when I grew up... with tubes... you could hear the Wehrmacht and Luftwaffe communicating with Berlin.
If would have the space and time I would really like to restore an old pair of 901.
I am a big fan of DSPed fullrange loudspeakers.
In the time domain the Bose concept has advantages.
The indirect sound field must be fun.
With a updated EQ it should sound well, too.
Fullrange and DSP measures like this (single driver):
Dsp corrected fullrange driver sandwiched with aluminium foil of thick quality - with measurements:
https://www.diyaudio.com/community/...w-distortion-with-a-2-way.334757/post-6711184
I am a big fan of DSPed fullrange loudspeakers.
In the time domain the Bose concept has advantages.
The indirect sound field must be fun.
With a updated EQ it should sound well, too.
Fullrange and DSP measures like this (single driver):
Dsp corrected fullrange driver sandwiched with aluminium foil of thick quality - with measurements:
https://www.diyaudio.com/community/...w-distortion-with-a-2-way.334757/post-6711184
Heads up for anyone wanting their 901's repaired, as of May 31 2024 Bose will no longer support repair of this product. As of today we have enough drivers to complete one more set of speakers with the black V2 drivers. We only have 16 of the blue cones. Personally I think this is the one product they should have supported till the end of Bose.
I know most could care less, but there is still a lot of people that enjoy their 901's for what they are. Just wanted to get the word out.
I know most could care less, but there is still a lot of people that enjoy their 901's for what they are. Just wanted to get the word out.
these where like bose in the direct/reflecting dept. so front side would be the single driver....listening to the 8 is a morass of comb filtering, i know i own a pair that underwent some frequency shading and turning it into a "kinda" dipole.
designer would have been some hungarian guy back in the late 60's early 70's do you really know who he is?
designer would have been some hungarian guy back in the late 60's early 70's do you really know who he is?
Yes, that makes sense to me. Previous comment I swapped front for back. 
The ratio of direct to reflected sound was the whole point of the original Bose design. (And I did know the designer Sherwin Greenblatt) The resulting sound stage was not really my cup of tea.
I guess the speakers you posted about would have been contemporaries to the original series 1?
The ratio of direct to reflected sound was the whole point of the original Bose design. (And I did know the designer Sherwin Greenblatt) The resulting sound stage was not really my cup of tea.I guess the speakers you posted about would have been contemporaries to the original series 1?
Had four of those pass thru here. Daniel loaded one pair up with a lot of ductseal on the cones to lower their resonance, he thot they sounded better, but he blew them up.
This is the driver used (much better than the ones udsed in the series 1):
These had the 8 drivers firing forward. The first time i went to a customer with 901s (was delivering an LP12), and made a great improvement by turning them around.
The best upgrade for a set of 901s is something else.
dave
Of course he first watched 327 YT videos on how to improve guitar sound, used platinum plated silver Litz wire and had it cryogenically treated.
Wow... This thread is kind of uncomfortable to read.
For what it's worth, the direct-reflected ratio of sound ties into other designs (as already mentioned) and there are a bunch of interesting parents to read about that. The fact that we don't all have Bose 901s or similar doesn't mean the design strategy never had any merit. Vinyl did have merit. Cds did have merit. But my kids don't know what they're for. We're kind of showing our age when we shout from rooftops what we perceive as current and prevalent. 🤭
What I did get out of this, is Scott's reference of the JBL Paragon and Metregon, and the JBL Aquarius range. I have been interested in the Metregon strategy for wide dispersion and flexibility (for the living room/TV, no one is in the sweet spot), but don't have the space for the round baffle. Seems like the Aquarius strategies are worth an experiment. It doesn't have to be ultrafi, just entertaining movie sound is fine.
So thanks to Scott for keeping it information and fact based. Any leads for interesting wide dispersing strategies is appreciated.
For what it's worth, the direct-reflected ratio of sound ties into other designs (as already mentioned) and there are a bunch of interesting parents to read about that. The fact that we don't all have Bose 901s or similar doesn't mean the design strategy never had any merit. Vinyl did have merit. Cds did have merit. But my kids don't know what they're for. We're kind of showing our age when we shout from rooftops what we perceive as current and prevalent. 🤭
What I did get out of this, is Scott's reference of the JBL Paragon and Metregon, and the JBL Aquarius range. I have been interested in the Metregon strategy for wide dispersion and flexibility (for the living room/TV, no one is in the sweet spot), but don't have the space for the round baffle. Seems like the Aquarius strategies are worth an experiment. It doesn't have to be ultrafi, just entertaining movie sound is fine.
So thanks to Scott for keeping it information and fact based. Any leads for interesting wide dispersing strategies is appreciated.
Some many years we modded a pair of 901s by replacing the fwd driver with an early KEF UniQ type…..I believe it was from their egg shaped satellites and maybe 4-4.5” driver? I didn’t do the wiring but recall a steep high pass was wired on to the KEF driver. The actually performed really well and spent a few years in a Manhattan boutique clothing store……SuperDry i think?….on the original stands side by side with a vintage Suzuki GS.
Well….point is…..they really were a fun speaker to listen to and in the right room with the right content could be a pretty convincing ‘you are there’ system. That being said, I certainly wouldn’t go out of my way to acquire a pair today. For those interested, given the generation baby boomers aging out, it’s very common to find 901s at estate sales these days…..especially here in the NY/NJ/ tri-state area where hifi was booming along with the generations institutional wealth.
Well….point is…..they really were a fun speaker to listen to and in the right room with the right content could be a pretty convincing ‘you are there’ system. That being said, I certainly wouldn’t go out of my way to acquire a pair today. For those interested, given the generation baby boomers aging out, it’s very common to find 901s at estate sales these days…..especially here in the NY/NJ/ tri-state area where hifi was booming along with the generations institutional wealth.