Vintage Bose Spatial Receiver...

[saltwater]

Anyone here have one that can comment on performance, build, im refering to the one w/ built in 901 eq. 100 wpc, and wood case, with flip down bottom.

 

[Parnelly]

Ive requested people to show theirs. Not so common of an amp. Apparently These are pretty nice units although i have never heard one my self. Lots of features on the spatial control receiver. Built in eq, spatial control, external eq jacks, im not positive but i think it can be used as a pre or a power. Also it has a neat little feature with the power switch on the back and once its on you touch the bose emblem on the front to turn it on. NOT to be confused with the smaller bose 550. Almost identical in look but smaller unit.

 

[cabinover]

I've seen one, that's all I can say about it. The guy thought it was worth a fortune and we agreed to disagree at that point.

They do have a unique look to them, rather stylish with the wood door and all.

 

[dshoaf]

I remember when they hit the street with typical Bose fanfare. Some years before, they had introduced the 901 Series III speakers that had a mysterious 3rd terminal that the Bose rep wouldn't discuss.

When the receiver hit the street, it was a 4-channel amp that fed a 2 channel signal to both speakers via this 3rd wire. This was accomplished by separating the inner 4 drivers in each 901 and feeding them with the channel of the opposite side. So, you have the front 5" speaker and the 4 outside, rearfacing drivers being driven from the appropriate channel plus the other 4 rearfacing drivers being driven from the other channel's signal - all in the same speaker. The way you rigged it was that the 4 drivers of the opposite channel were to be connected so that they were the ones closest to the other speaker. Got all that so far?

Next, the Spatial control on this Bose receiver then allowed you to control the amount of perceived fill between the speakers. In other words, you were messing with the soundstaging by controlling how much of the Left signal was fed to the Right speaker and vice versa. I suppose all it really did was fill the hole in between the speakers and not image-based soundstage we hear today. I'm not clear that the electronics in the Bose was that good.

Did customers like it? I don't know but I do know that they didn't understand it and couldn't appreciate what it was doing. Bose quickly dropped all the fanfare.

I don't really know what happened after that. It was about then that I left the audio biz for the then-new mini-computer business.... Judging from the how many we see these days, I'd bet that not many Bose Spatial Receivers were sold.

Cheers,

David

 

[atozeghers]

Hi David,

I have this Bose Spatial Control Receiver and a pair of Bose 901's that i just came into possession of.

Do you know if you are able to just hook up these speakers normally, without the 3rd input, which is labeled "*" ?? For example, if I used a different amp, would I just connect the 3rd "*" input also to the "+" terminal on the amp to get the 4 inner drivers to play the appropriate channel?

I will have to do some tests I guess, and see what happens. Just don't want to mess anything up and there is very little information about any of this online!

best,

-Aaron

I remember when they hit the street with typical Bose fanfare. Some years before, they had introduced the 901 Series III speakers that had a mysterious 3rd terminal that the Bose rep wouldn't discuss.

When the receiver hit the street, it was a 4-channel amp that fed a 2 channel signal to both speakers via this 3rd wire. This was accomplished by separating the inner 4 drivers in each 901 and feeding them with the channel of the opposite side. So, you have the front 5" speaker and the 4 outside, rearfacing drivers being driven from the appropriate channel plus the other 4 rearfacing drivers being driven from the other channel's signal - all in the same speaker. The way you rigged it was that the 4 drivers of the opposite channel were to be connected so that they were the ones closest to the other speaker. Got all that so far?

Next, the Spatial control on this Bose receiver then allowed you to control the amount of perceived fill between the speakers. In other words, you were messing with the soundstaging by controlling how much of the Left signal was fed to the Right speaker and vice versa. I suppose all it really did was fill the hole in between the speakers and not image-based soundstage we hear today. I'm not clear that the electronics in the Bose was that good.

Did customers like it? I don't know but I do know that they didn't understand it and couldn't appreciate what it was doing. Bose quickly dropped all the fanfare.

I don't really know what happened after that. It was about then that I left the audio biz for the then-new mini-computer business.... Judging from the how many we see these days, I'd bet that not many Bose Spatial Receivers were sold.

Cheers,

David

 

[dshoaf]

The short answer is, yes, you can run the 901s without using the Spacial feature, which requires the 3rd wire to both speakers. If you don't have it, obtain a copy of the Owners Manual. It describes how you set it up to do this.

Odds are, however, that the switches you'll be throwing to do that are dirty - mine were. DeOxit will help them. Specifically, those small switches just above the speaker terminals on the receiver will need attention. 2 of these switch in/out the 901 EQ while the other 2 control the mapping of the 4 amps. They're labeled as 4/8 ohm switches but that's what they're doing.

You should also spend some time learning how these wiring options and switch options affect what controls on the front of the receiver do.

Cheers,

David

 

[atozeghers]

Okay thanks David. I will take a look in the manual and do some tests.

If I'm hooking up the speakers through a different stereo receiver I wonder how that would work then? If I just hooked up the "+" and "-" cables from the speakers and left the 3rd "*" line, would the 4 inner drivers just not play? Or would they just work normally as pure L+R with no cross-mixing... Will have to do some tests.

Thx,

-Aaron

 

[Monad]

I thought the third wire was just for 2 series of Bose that had it.. I used the spatial setting with my series VI to good effect, just running 2 wires. Call the bose folk to confirm but pretty sure that's it.. Do you have your manual for the receiver?

Sry, late to the conversation..

 

[Monad]

Hi Aaron, I have one of these Spatial Receivers and have the series VI which don't have the Series III and IV 901s 3rd connector. I just hooked the VI up w 2 wires and all speakers performed well and sounded as expected. I also had a Bose 1800 series VI pro amp pushing them, so the sound did boom fairly well.

Moving the Spatial slider does change the sound without the 3rd wire so, not sure what it's supposed to sound, better though with an extra 450wpc pushing them.

Overall, the receiver is nice and has an interesting sound that I like. I'm going to pair it with some KEF 105.4 this week, after I pick it up from service.. I'm interested to see how the receiver sounds, outside of the 901 world.

 

[atozeghers]

Hey, yes I noticed that the spatial slider did do something with another pair of generic speakers I had plugged into the Bose Spatial Receiver.

I’m just replacing the surrounds and refinishing the wood on my 901s right now so I haven’t tested them out yet. I would assume that the 3rd speaker wire MUST do something though (when paired with this receiver specifically), so I am inclined to believe the gentleman above. I downloaded the Bose Spatial Control Receiver manual from HiFi Engine (https://www.hifiengine.com/manual_library/bose/spatial-control-receiver.shtml). It explains how to correctly plug in both the 901s with the 3rd speaker cable and regular speakers but doesn’t really elaborate on what the difference is. I also noticed in the manual for the Bose 550 it says that the 3rd “*” speaker input is “for future technological innovations and should not be used” or something to that effect. Kind of funny. Would love to know more.

Once I get a chance to test it out a bit I will update here...

 

[Monad]

Well, the Bose folk currently running the shop don't know much about it either.. Would be nice to find the engineers who designed the receiver, find out what they were thinking. It sounds like the receivers didn't sell very well in a competitive high-end market. Probably they needed customers to buy both receiver and 901s to make it relevant.

Maybe it didn't really work outside the lab, or the cost factor to implement was too high.. or put too much control in the customer's hands.--> i.e. the K.I.S.S product dev mantra was ignored, then remembered.

It's a pretty receiver, with great sound. I'm excited to get it back but not sure how long it will stick around with the recent preamp and speaker acquisitions.

 

[Pio1980]

Was it a gimmick to sell new gear or an advance to help widely spaced 901s "fill" the center? I dunno, but properly functioning and placed pairs of good conventional speakers provide a normally proportioned panoramic stereophonic presentation without the complexity.

 

[SX550]

I had a set of series 3 901. Mine didnt have a third terminal. I used the original eq that came with it.

I loved the sound but they require too much room and power which i don't have.

 

[dshoaf]

For those on this thread that are interested in understanding how the Spatial feature worked, here's how the 3 wire system is set up.

Bose 901 Series III and IV and later used 9 drivers wired in series. Each driver is rated at 0.9 ohm so 9 x 0.90 ohms = 8.1 ohms.

Now, if you tapped off the series string of drivers at the 4th driver and bring it out to the cabinet, you have a way to wire those drivers to be driven by a separate amp. This is shown below as +G and -G. So, if we feed each 901 with a left and right channel of a 2-channel playback, we can not feed the inner 4 drivers with the signal from the other channel.

Then, we can use the Spatial control to vary the mix of Left and Right channels in each speaker. Of course, this takes 4 separate power amps to work, which is actually what is inside the Bose Spatial Receiver.

Further, the Spatial Receiver could be set up to strap 2 of those channels together if you didn't or could not use the 901s with 3 terminals. All this is explained in the Owners Manual but the wiring of the speaker itself isn't.

It was a slick trick to make this all work but, as PIO1980 mentions, the debate on its worthiness remains after these 40+ years.

Cheers,

David

 

[Audiokingman]

Hi Aaron, I have one of these Spatial Receivers and have the series VI which don't have the Series III and IV 901s 3rd connector. I just hooked the VI up w 2 wires and all speakers performed well and sounded as expected. I also had a Bose 1800 series VI pro amp pushing them, so the sound did boom fairly well.

How does the external Bose 1800 amp connect to the Bose receiver?
A friend wants to use his receiver as a tuner/preamp only and use the big 1800 amp as the power to his Bose 901 speakers.

 

[Monad]

preamp outs, rca

 

[Audiokingman]

preamp outs, rca

There are 4 preamp outs numbered 1,2,3,4.

Which do you hook up to the amp?

 

[Monad]

i want to say the right from both 1 and 2 but I don't have it anymore and can't really recall.. been a few years and it's the only receiver I ran like that. look up manual?