Tweaked out Bose 901 series 6 mk 2

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HiFiSoundGuy

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Tweaked out Bose 901 series 6 mk 2
« on: 3 Dec 2011, 07:35 pm »
 I did some tweaks to my new Bose 901's that made sound MUCH...BETTER !!...

  I took off the front and back grills because these grills COLORED the SOUND TOO MUCH !

  With the the grills OFF these 901's sound cleaner and much more open and more realistic too !

 Another tweak I did to them was putting some self-adhesive foam insulation around the front speaker driver.

 Everything now sounds SOOO SPOOKY REAL now !!...

  These 901's don't sound anything like they used to sound, its a NIGHT and DAY DIFFERENCE !

 I think these 901's would get a lot more love if they only knew how good these 901's can sound with these tweaks !!...  8)

  I now love these 901's with most of the speaker drivers facing the front wall !.........

doorman

Re: Tweaked out Bose 901 series 6 mk 2
« Reply #1 on: 3 Dec 2011, 08:34 pm »
Single driver /wide bandwidth speakers??
don

SlushPuppy

Re: Tweaked out Bose 901 series 6 mk 2
« Reply #2 on: 3 Dec 2011, 08:40 pm »
What AMAZING!!!! product will you be telling us about next month?

Good grief!  :duh:

vinyl_lady

Re: Tweaked out Bose 901 series 6 mk 2
« Reply #3 on: 3 Dec 2011, 09:02 pm »
Funny that someone would post something about Bose 901s. Yesterday Paul McGowan (PS Audio) posted this blog about his 901 llistening experience. I think it is very instructive.
Quote
Drink more beer!

My post of a couple of days ago entitled Like Bose? wasn’t meant to bash their products, just relaying a story.  It sure got a lot of people talking so I thought, well, what the heck.  Let’s go bashing!

I am reminded of a story years ago that involved the manager of our local Pacific Stereo store and a pair of Bose 901 Direct Reflecting loudspeakers.

So for those of you that don’t remember, the first big product Bose ever had was a speaker that used all small drivers (I think they were 5″) that were heavily EQ’d to increase the bass and treble to something close to “flat”.  They then pointed the speakers at the rear wall to give a big concert hall effect.  It actually wasn’t a bad idea and in some cases could sound pretty good.  Not in this case, unfortunately.

The manager of the store, Bill, was a total Bose devotee who owned all Bose electronics, the speakers and then dedicated a room to the system.  In a Bose dedicated room what you did was reinforce the rear wall to achieve maximum reflectivity.  In this case a floor to ceiling set of bricks were cemented into place to act as a reflector for the sound.

The 901′s were notoriously inefficient because of the need to EQ them, so this required a huge amplifier (which Bose made) of which Bill had and was quite proud of.

One day, while in the store, he cornered a couple of us and was raving about the great sound he was getting.  ”Concert hall performance” in his listening room.  Had to be heard to be believed.  We were taunted into coming to hear this because we were “Audiophiles” who made fun of Bose and we needed to be set straight on how music really could sound.

Came the big day we were ushered into Bill’s living room, offered a beer (which I declined) and spent the next 30 minutes listening to Bill talk up the system’s virtues.

Then he placed the needle onto the album and we started to listen.

I think I lasted through half of the first track before I went to cover my ears up.  Seriously, this wasn’t Audiophile snobbery on my part this was pain avoidance.

“Bill, can you turn it down?”  I yelled over the music.

“You can’t enjoy a concert with the volume down” Bill yelled back.

“Yes, but doesn’t this hurt your ears?”

“Yeah, but then I just drink more beer and it sounds great”.

By golly, best advice I’ve ever gotten for a tweak.

Harry Pearson responded to Paul's blog:
Quote
The creation of the Absolute Sound

After reading yesterday’s post about the Bose 901 system I got a note from Harry Pearson and I am reprinting it in today’s post (with his kind permission).

“Perhaps I should tell you how this very speaker system prompted the creation of The Absolute Sound.

hint: it started with the two page up front review (not in the review section) of High Fidelity written by Norman Eisenberg. Unprecedented coverage and yet no one seems to have thought of the obvious philosophical and intellectual reason it couldn’t work…the Bose “scientists” said the company’s men had made measurements of Symphony Hall in Boston and found a direct/to/reflected ratio of sound there and thus modeled the 911 on that.

What this meant if you think about it, even a recording made in the hall would be wrong, and a recording made in any other hall would have to be wrong.

….and moreover the Bose engineers, because of the company’s paucity of money at that point were seated under the balcony, the worst place to make a measurement.”


 :beer:

TONEPUB

Re: Tweaked out Bose 901 series 6 mk 2
« Reply #4 on: 3 Dec 2011, 09:45 pm »
It's funny because we've been talking about reviewing a pair on our Facebook page for about a week now.

And the OP here is always threadcrapping on Steve Hoffmans forum about how his Bose 901's are the most amazing speaker in the world, no matter what the topic.

So, much like the Klipsch Heresy's (which we found to be an excellent speaker) and the Technics 1200 (which, thanks to a number of people on this and SH's forum have found to have a lot of potential) I've ordered a new pair of Bose 901's to listen to.

I've only heard them in the Bose store, so curious to see what this $1400 pair of speakers is actually capable of.  Everyone in the high end loves to bash Bose, so let's investigate!

SlushPuppy

Re: Tweaked out Bose 901 series 6 mk 2
« Reply #5 on: 3 Dec 2011, 09:52 pm »
It's funny because we've been talking about reviewing a pair on our Facebook page for about a week now.

And the OP here is always threadcrapping on Steve Hoffmans forum about how his Bose 901's are the most amazing speaker in the world, no matter what the topic.

So, much like the Klipsch Heresy's (which we found to be an excellent speaker) and the Technics 1200 (which, thanks to a number of people on this and SH's forum have found to have a lot of potential) I've ordered a new pair of Bose 901's to listen to.

I've only heard them in the Bose store, so curious to see what this $1400 pair of speakers is actually capable of.  Everyone in the high end loves to bash Bose, so let's investigate!

You must let us know how SPOOKY REAL they are after you remove the drivers grills 8)

TONEPUB

Re: Tweaked out Bose 901 series 6 mk 2
« Reply #6 on: 3 Dec 2011, 10:06 pm »
In all honesty, I am curious to see what they are all about.  I haven't' heard them in a decent demo for years, so we're going to hook em up to a budget receiver, some decent separates that are still affordable and my Burmester amp, preamp and dCS stack to see where the limit of their performance is.

And we're even flying one of our readers out to sit in and give the whole thing a listen as well as getting some input from my next door neighbor, who thinks all this expensive hifi is crazy, but ends up usually liking the sound of the good stuff.

So, we'll see what's in store.  We've had a lot of traffic on our FB page with a lot of varying opinions on the subject.

HiFiSoundGuy

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Re: Tweaked out Bose 901 series 6 mk 2
« Reply #7 on: 3 Dec 2011, 10:08 pm »
Single driver /wide bandwidth speakers??
don

     With these 901's you are taking things to the next level !

HiFiSoundGuy

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Re: Tweaked out Bose 901 series 6 mk 2
« Reply #8 on: 3 Dec 2011, 10:11 pm »
It's funny because we've been talking about reviewing a pair on our Facebook page for about a week now.

And the OP here is always threadcrapping on Steve Hoffmans forum about how his Bose 901's are the most amazing speaker in the world, no matter what the topic.

So, much like the Klipsch Heresy's (which we found to be an excellent speaker) and the Technics 1200 (which, thanks to a number of people on this and SH's forum have found to have a lot of potential) I've ordered a new pair of Bose 901's to listen to.

I've only heard them in the Bose store, so curious to see what this $1400 pair of speakers is actually capable of.  Everyone in the high end loves to bash Bose, so let's investigate!

    Yes PLEASE do investigate ! 

HiFiSoundGuy

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Re: Tweaked out Bose 901 series 6 mk 2
« Reply #9 on: 3 Dec 2011, 10:17 pm »
You must let us know how SPOOKY REAL they are after you remove the drivers grills 8)

   Your never here these 901's FULL POTENTIAL until you REMOVE all the grills and put some self-adhesive foam around each front speaker driver ! I used some of the foam that BOSE put on the back grills to put around the front driver.

 Another thing with all the grills OFF these 901's is speaker placement is now NOT that important !  8)

Russell Dawkins

Re: Tweaked out Bose 901 series 6 mk 2
« Reply #10 on: 3 Dec 2011, 11:42 pm »
Another thing with all the grills OFF these 901's is speaker placement is now NOT that important !  8)

Hmmm. With 901s I've always found placement very important. 

In the next room often works.  (badaboom)  :)



I kid, I kid!

srb

Re: Tweaked out Bose 901 series 6 mk 2
« Reply #11 on: 3 Dec 2011, 11:54 pm »
I have a single ambience tweeter facing rearward on my Opera floorstanders.  Anything more than that just results in a huge jumbled mess of reflected sound.
 
Steve

JLM

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Re: Tweaked out Bose 901 series 6 mk 2
« Reply #12 on: 4 Dec 2011, 01:31 am »
Why should we be surprised that a tweak could significantly help a very medicore speaker?

9 cheap drivers versus 1 good one for the same price?  How does that make any sense?

If (big if) 8/9th's of all sound is reflected, why multiple the effect with the speakers?

The amount of reflection will of course vary by venue (and I'll leave it up to the mastering folks to figure that out for a studio recording).  And of course this could lead into the whole dipole/array debate.  IMO bipole/omnipole is different from dipole/arrays and valid, but I've never owned anything but front firing speakers.


Soundminded

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Re: Tweaked out Bose 901 series 6 mk 2
« Reply #13 on: 4 Dec 2011, 02:01 am »
Funny that someone would post something about Bose 901s. Yesterday Paul McGowan (PS Audio) posted this blog about his 901 llistening experience. I think it is very instructive.Harry Pearson responded to Paul's blog:
 :beer:

RE Harry Pearson's letter, Dr. Bose made his measurement of 89% reflected sound, 11% direct sound 16 feet from the performing stage, not under a balcony. This was from his white paper explaining the concept of 901. As you go further back in Boston Symphony Hall, the percentage of reflected sound increases to the point where that's practically all you hear.

Original 901 was not made of 18 cheap little speakers, the drivers were 30 watts RMS each manufactured by CTS. In the original and series II they were sorted into three groups so that the units in each enclosure would be a close match for each other. They were extremely inefficient because Bose deliberately pushed up the system resonance frequency above 180 hz where he said that phase shift associated with resonance became inaudible. The first 2 series were acoustic suspension designs which exploited the linear falloff below resonance at 12 db per octave. But the equalizer only supplied a 6 db per octave boost. At normal listening levels there isn't enough bass. That's one reason people play these at very loud levels. There's also an upper bass lower midrange peak of about 7 to 8 db which makes the midrange sound thick and heavy. And to make matters worse the speaker can't reproduce the top octave making the treble muffled. So the saying no highs, no lows, it's Bose has some validity to it.

It took me 4 years on my second try to successfully re-engineer my original 901s. I don't expect anyone to believe what I'd say about them but they don't sound anything like anyone else's 901s including Dr. Bose's.

Starting with Series III Bose manufactured his drivers himself and began using a ported enclosure. It seems to be some sort of transmission line design. It is much more efficient but it sacrifices the lowest octave of sound. From version III onward it is not a difficult load for an amplifier to drive even with the equalizer. I heard Series VI at a Bose store in Newport Beach Ca about 4 years ago while I was on a business trip and had some time to kill. It still sounded disappointing to my ears in much the same way the original as manufactured does. Still no high end.

Russell Dawkins

Re: Tweaked out Bose 901 series 6 mk 2
« Reply #14 on: 4 Dec 2011, 02:16 am »
Any small CTS driver that had a hard cardboard dust cover like the one on the original 901 has a quack in the midrange, in my experience, and the driver used by Bose I think fit that description. I made a Bose 901 clone back in '73 with Philips 4.5" drivers with whizzer cones which sounded substantially better than the 901 through the mids.
One thing Bose did that I wished I could do at the time was order the drivers with 64 ohm voice coils so he could parallel them.

Anyway, it's refreshing to encounter someone with as much inside knowledge on the 901 as you apparently do, Soundminded.

questfortone

Re: Tweaked out Bose 901 series 6 mk 2
« Reply #15 on: 4 Dec 2011, 02:30 am »
Bose are you f@cking kidinging me.!!!!! Get some real speakers like JBl's.

JLM

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Re: Tweaked out Bose 901 series 6 mk 2
« Reply #16 on: 4 Dec 2011, 03:06 am »
Wish I could remember the model, but my first "serious" speakers were JBL's from the 70's: large standmounts that used a single 8 inch driver with a 8 inch passive radiator.

persisting1

Re: Tweaked out Bose 901 series 6 mk 2
« Reply #17 on: 4 Dec 2011, 03:10 am »
Is taking off speaker grills considered a "tweak"? 

Soundminded

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Re: Tweaked out Bose 901 series 6 mk 2
« Reply #18 on: 4 Dec 2011, 03:12 am »
Any small CTS driver that had a hard cardboard dust cover like the one on the original 901 has a quack in the midrange, in my experience, and the driver used by Bose I think fit that description. I made a Bose 901 clone back in '73 with Philips 4.5" drivers with whizzer cones which sounded substantially better than the 901 through the mids.
One thing Bose did that I wished I could do at the time was order the drivers with 64 ohm voice coils so he could parallel them.

Anyway, it's refreshing to encounter someone with as much inside knowledge on the 901 as you apparently do, Soundminded.

It was an interesting idea with many innovative features and it broke sharply with all prevailing opinions and methods. It was radical. IMO the design failed because it was inexpertly executed. When properly exploited it can actually do things that were never claimed for it, it can be re-engineered to reproduce the sound of musical instruments accurately, hard to believe. It cannot reproduce concert hall acoustics. That is far beyond the current state of the art.

The pair I bought in 1970 was used for a few years and then put in storage for decades. Rather than bash a product I find flawed but with some unique advantages, I looked to find out what I liked about it and fix what I didn't.  It took a long time to apply what I had learned over a period of many years to figure it out and then two tries, the first one ending in complete failure. The second one as I said took four years even knowing exactly what I needed to do with it. I've re-engineered most of my speakers having found few that I like as they were manufactured. Even where I do like them, I find I have to equalize a system for each recording to get the instruments to sound right. I've had several successes and a few I'm still working on or haven't gotten to yet. In most ways this is my most successful effort so far.

TONEPUB

Re: Tweaked out Bose 901 series 6 mk 2
« Reply #19 on: 4 Dec 2011, 03:27 am »
so are you guys saying the original 901's actually sounded better then?
I do seem to remember a few bars where I grew up that used them with McIntosh gear that actually sounded decent in that environment...