The man in the photo is described in this post:Inductor: I did look at the photo in post #4. I am guessing the man relaxing in his high rise loft is living in the advertising world. He has a pair of Bose 901 that don't require any cabling, nor is any type of electronic gear required to drive them. He has almost no furniture in a spotless room. This does not look like any real world living room I have ever seen. Who is the gullible one?
http://www.diyaudio.com/forums/anal...screte-opamp-open-design-129.html#post3314333
(Discrete Opamp Open Design post #2579)
Where are you placing the tweeters? (in the middle of the baffle?, or just testing with them on top, may not be a bad idea)?
. A picture of the set (901 series) would help. series I & series II.
. We have to go to the originals xovers layouts for series I & II (links).
. Are you starting on the series I or II?
. How much you think is the (901) SPL (to match with the tweeter).
. You can use a variable L-Pad (for help/testing) with the high pass crossover.
Note (about design in general for soap opera and football lovers): pic.1 vs. pic.2 I like the idea of having clean rooms where we can concentrate on music. People hate the idea of not using loudspeaker cables when listening to the music because they can't understand (many musicians also don't have cables when playing the guitar on TV). Some people also prefer small rooms full of clutter where you don't have the space to move and besides it stinks. That's so wrong... shame on them!
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BOSE people think they are the new age messiahs.
That's why I love vintage BOSE's.
That's why I love vintage BOSE's.
Bose Listening Room Bar Stools
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-3dB for crossover high pass (various with EQ box response) ~5kHz, 6kHz, 8kHz (atten. 5dB/one driver & back wall unequalized response), 12kHz.
Enclosures for Old bose drivers - diyAudio
Bose 901 series 1 & 2 equalizer - audiokarma
Bose 901 System - Equalizers By Roger Russell
Enclosures for Old bose drivers - diyAudio
Bose 901 series 1 & 2 equalizer - audiokarma
Bose 901 System - Equalizers By Roger Russell
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I will probably use the pair of Bose 901 (series I or II -- no labels) that a prior owner ("victim"?) had re-drivered (is that a verb?). Plan was to pull out front driver only and replace it with the tweeter. How to wire it will require some thought. I know almost nothing about x-overs. I know I need at least one capacitor. Perhaps for testing, it would be easier to have it separate and feed it from the input (series R + capacitor). I know enough about audio electronics that putting the full range signal through the tweeter will not make it happy
Again, here is the tweeter that I will use:
http://www.parts-express.com/pe/showdetl.cfm?partnumber=264-348
My "design specifications" preliminary are more or less: I want the tweeter to be active from about 5K-20K. For initial testing, I agree that it will be easier to have the tweeter free mounted (there are, in fact, two pairs of 901s in my current system). Also, a 2nd amp (also a NU3000) is available, also a miniDSP if I need to tweak the x-over. Maybe that is the easiest thing to do: I can decide where I want the x-over to be and then, if I choose to make one, worry about a x-over design, something I know absolutely nothing about.
Again, here is the tweeter that I will use:
http://www.parts-express.com/pe/showdetl.cfm?partnumber=264-348
My "design specifications" preliminary are more or less: I want the tweeter to be active from about 5K-20K. For initial testing, I agree that it will be easier to have the tweeter free mounted (there are, in fact, two pairs of 901s in my current system). Also, a 2nd amp (also a NU3000) is available, also a miniDSP if I need to tweak the x-over. Maybe that is the easiest thing to do: I can decide where I want the x-over to be and then, if I choose to make one, worry about a x-over design, something I know absolutely nothing about.
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Bose 901 EQ = Amplifier Killer
MLStrand56
Anybody who is considering 901's should read Dr. Bose's White Paper on their design. The 901 EQ pumps up the Bass & Treble by 30db to counteract the 901's terrible low & high end. For those that don't understand db, 30db is 1000 times higher. So the pwr. amp is required to deliver 1000 times more power to the Bass & Treble, than to the Midrange. How many power amps can deliver That kind of pwr?
MLStrand56
It's not 30dB. Iirc, the bass boost has two positions, one is like 12dB, the other is either higher or lower than that. Regardless they require a high power amplifier.
As far as replacing the front driver with a tweeter - likely a not so good idea.
Better to run it on top. The other thing is that unless you need/want to maintain the original look entirely, I'd make a new hole in the front to mount the tweeter, and modify the grille cloth assembly by knocking a new hole in the grille assembly to give the new tweeter a hole.
IF the drivers have 3 ears, then they are not series 1, the original bose drivers had standard 4 ear stamped frames.
The wiring is series parallel, to give roughly a nominal impedance of between 4 and 8 ohms, the original reviews/specs will tell that.
Best not mess with that.
So your new tweeter(s) will go across the existing driver array. In other words, from the speaker connections, via a crossover, to the tweeter(s).
As far as replacing the front driver with a tweeter - likely a not so good idea.
Better to run it on top. The other thing is that unless you need/want to maintain the original look entirely, I'd make a new hole in the front to mount the tweeter, and modify the grille cloth assembly by knocking a new hole in the grille assembly to give the new tweeter a hole.
IF the drivers have 3 ears, then they are not series 1, the original bose drivers had standard 4 ear stamped frames.
The wiring is series parallel, to give roughly a nominal impedance of between 4 and 8 ohms, the original reviews/specs will tell that.
Best not mess with that.
So your new tweeter(s) will go across the existing driver array. In other words, from the speaker connections, via a crossover, to the tweeter(s).
Hi,
I flush mounted a Vifa 1" silk dome tweeter in the front of mine and it worked great for use without the EQ box, and put an L-pad on the bottom, so I could use them with the EQ box. Definitely keep the 9 drivers and add the tweeter in parallel with them.
250 watts is plenty of juice. I accidentally had the grills flapping an inch and I'm surprised I didn't kill the drivers. I used a Harman Kardon Signature 1.5. More than that's definitely unnecessary.
M
I flush mounted a Vifa 1" silk dome tweeter in the front of mine and it worked great for use without the EQ box, and put an L-pad on the bottom, so I could use them with the EQ box. Definitely keep the 9 drivers and add the tweeter in parallel with them.
250 watts is plenty of juice. I accidentally had the grills flapping an inch and I'm surprised I didn't kill the drivers. I used a Harman Kardon Signature 1.5. More than that's definitely unnecessary.
M
Beyond the midcentury modern appearance, I'm curious why interest persists in the 901. Bose themselves seem to have done an improved version of their direct/reflecting concept in their 601: more bass (larger cabinet, dual 8" woofers) and cleaner sound due to an actual crossover (be it electrical or mechanical, not quite sure) between the widebanders and the woofers.
A shisha lounge we frequent uses them as house speakers, and while they don't sound good, they're reasonably consistent-sounding across the space. I've thought about taking the basics of that design and experimenting with them as surround speakers, perhaps with four of the little 3" KEF eggs per side, or Aura NS3's.
A shisha lounge we frequent uses them as house speakers, and while they don't sound good, they're reasonably consistent-sounding across the space. I've thought about taking the basics of that design and experimenting with them as surround speakers, perhaps with four of the little 3" KEF eggs per side, or Aura NS3's.
Pallas,
You use 901s or 601s?
Very different speakers.
The interest persists in 901s because they are classics, they put out a lot of sound in a small package, and as I said they sound pretty darn great playing Led Zep, assuming you have a mostly blank, flat, plaster & lathe wall, proper amplification and enjoy a big sound... I think one can do much better today by a variety of means, but that's coming from someone who has been there and done that 901 and variations thereof.
You use 901s or 601s?
Very different speakers.
The interest persists in 901s because they are classics, they put out a lot of sound in a small package, and as I said they sound pretty darn great playing Led Zep, assuming you have a mostly blank, flat, plaster & lathe wall, proper amplification and enjoy a big sound... I think one can do much better today by a variety of means, but that's coming from someone who has been there and done that 901 and variations thereof.
God no.
For mains, I would and do use much better types of designs. Specifically, concentric drivers with additional woofers to reduce midrange cone/waveguide movement.
These kinds of designs do strike me as potentially useful for surround/ambiance channels in a multichannel system geared to music, though.
But you didn't address my point, which is that the 601 seems like a more thoughtful approach than the 901 to the same basic design goals. It sprays stuff everywhere in a similar pattern (depending on how aimed) but has more meat on the bottom. So, besides the looks, why do people seeking to emulate Bose look to the 901 as their model, rather than the 601?
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OK I can resist the temptation no longer.
I just ordered a pair of the "Selenium ST200" tweeters from Parts Express ($50.03). In theory I have just increased the value of a pair of my 901's by about 20%. Ah, now to wait for the arrival of the package.
That is the 'glass half full' way of looking at it.
More realistically you merely reduced the value of the ST200s. ;-)
From their vintage looks, maybe because they don't touch the floor (with a similar design format/appearance of the GALE's GS401 Speaker) they float in mid air with the pattern of reflective dispersion of sound and technically because they didn't have that amount of problems with phase shift that afflict 2/3-Ways and plus they seem pretty radical with those 8 FR firing to the back and one to the front...
more ideas for f**king with Bose 901's
Having all these items already on hand (except tweeters on order), it occurs to me:
What experimental options exist, having the following:
MiniDSP 2x4
(2) Behringer NU3000 amps
(6) Bose 901 series I or II (only 4 currently in use).
With the MiniDSP, the possibility exists to set an individual EQ for each speaker as well as a delay. This makes for an interesting possibility, using the above equipment to make a system with adjustable "first echo" from the front. I could put the "rear" pair in the usual place, whose output I would delay by adjustable amount, and the "front" pair would be turned around backwards (8 speakers to the front).
Anybody want to go completely "off the deep end"? How about 18 individual EQ/delay, amp lines and wire to each of the (original) 901 speakers?
Having all these items already on hand (except tweeters on order), it occurs to me:
What experimental options exist, having the following:
MiniDSP 2x4
(2) Behringer NU3000 amps
(6) Bose 901 series I or II (only 4 currently in use).
With the MiniDSP, the possibility exists to set an individual EQ for each speaker as well as a delay. This makes for an interesting possibility, using the above equipment to make a system with adjustable "first echo" from the front. I could put the "rear" pair in the usual place, whose output I would delay by adjustable amount, and the "front" pair would be turned around backwards (8 speakers to the front).
Anybody want to go completely "off the deep end"? How about 18 individual EQ/delay, amp lines and wire to each of the (original) 901 speakers?
901
They were so perfect, that they steal the show. (Never owned them... you must need some space ?!)
(pic from here Bose 901 Magic or Myth?)
Bose 901 Response Graph - AudioKarma.org
Bose 901 Speaker Restoration
Notice how drivers were same impedance as speaker on series II and III - series/parallel layout - and 1R on series VI/series layout, from this linked page.
They were so perfect, that they steal the show. (Never owned them... you must need some space ?!)
(pic from here Bose 901 Magic or Myth?)
Bose 901 Response Graph - AudioKarma.org
Bose 901 Speaker Restoration
Notice how drivers were same impedance as speaker on series II and III - series/parallel layout - and 1R on series VI/series layout, from this linked page.
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While you're at it, why not use a spring reverb to add more wash to the 901 direct/smeared sound
?
I have sold both oil can echos I owned, but still own a bucket brigade IC echo and can do tape delay with two head cassette recorders.
None of those have the "reverb" sound needed for the direct/smeared sound.
Still have a reverb pan, the best part of the Bose 901 era was hearing pan reverbs clanging in cars equipped with them when you hit bumps.
Hmm, actually the performance enhancing substances were better than that memory, I think...
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i worked there for awhile.
(early 80's.)
they had the xovers as well.
didn' see the tweeters tho ...
i've only got 10 examples of these.
8 nib.
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audio magazine had an interview w/ted in the late 90's.
after he had designed the maximus system,
his superiors told him that he was to use the magnets
we now see on these drivers.
'as they had 10,000 of them.'
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