Bose 901s run done

westmassguy

HzTweaker wrote: »

I'm not trying to be a thread jacker but I just spent a week hanging out with my Pops who had recently acquired a pair of 501s. Loved the big sound they produced, but the left woofer would pop at loud volume. Quick question: where is a good starting point to look for a replacement driver?

Pull the grills. Most likely they both need a re-foam, not replacement, unless they've been damaged due to operating them with rotted foam.

HzTweaker

Thanks @westmassguy . I'll let me Dad know to check it out and I'll PM you his findings. Back to the subject: I always like the look of the early 901s. There's just something about the look of all those drivers and cabinet shape that I find really appeasing to my eye. I would love to get my ears on a pair that's properly set up.

westmassguy

Not sure what Series 501s they are, but Bose used about 500 1/8" wide staples to secure the grills. He must use caution, and pry them off gently, otherwise the Masonite will break. I use an upholstery tool called a staple lifter to remove them.

HzTweaker

Copy that. Thanks for the tip.^^ When I seen the staples I thought it might have been a bad DIY job. Shows you what I know.

These are it:

westmassguy

There's a 10 woofer, and their sealed/acoustic suspension.
I believe those are Series II with the little turning vane on the tweeter.

WTS

No connection:

https://albany.craigslist.org/ele/5806245148.html

https://albany.craigslist.org/ele/5728551308.html

http://westernmass.craigslist.org/ele/5789110938.html

http://hudsonvalley.craigslist.org/ele/5804203145.html

http://westernmass.craigslist.org/ele/5710713998.html

http://hudsonvalley.craigslist.org/ele/5745497004.html

http://hudsonvalley.craigslist.org/gms/5784692191.html

maximillian

voltz wrote: »

Glad your with Bose and enjoying it and I am sure you can appreciate like many us his talent (Dave's) & that he gives advise freely so quickly to anyone needing help on the forum!

I personally don't know Dave's skills since I have never used him or know of his website. Kudos to him for his talent and service.

I joined club Polk in 2008 and went to work at Bose in 2014. My house is filled with Polks and now I am getting some Bose stuff. I have LSi setups for my Home theater and my living room for several years now. But I complemented my home with SoundTouch 10's which enable whole house audio over Wifi (that wasn't meant to be an advertisement :-p ). Oh yeah, I have acquired a few too many headphones too, but had Ultrafocus 8000's before I joined.

The biggest common denominator is that the people I work with love music. Most people are musicians to some degree. I love going to work and hearing music blasting from one of the sound rooms. It's a vibe that didn't exist when I worked for companies in other industries.

HzTweaker

westmassguy wrote: »

There's a 10 woofer, and their sealed/acoustic suspension.
I believe those are Series II with the little turning vane on the tweeter.

For give my ignorance, what is sealed/acoustic suspension?

westmassguy

HzTweaker wrote: »

westmassguy wrote: »

There's a 10" woofer, and they're sealed/acoustic suspension.
I believe those are Series II with the little turning vane on the tweeter.

For give my ignorance, what is sealed/acoustic suspension?

Get your learn on:
https://en.wikipedia.org/wiki/Thiele/Small
https://en.wikipedia.org/wiki/Acoustic_suspension
https://en.wikipedia.org/wiki/Bass_reflex

HzTweaker

westmassguy wrote: »

HzTweaker wrote: »

westmassguy wrote: »

There's a 10" woofer, and they're sealed/acoustic suspension.
I believe those are Series II with the little turning vane on the tweeter.

For give my ignorance, what is sealed/acoustic suspension?

Get your learn on:
https://en.wikipedia.org/wiki/Thiele/Small
https://en.wikipedia.org/wiki/Acoustic_suspension
https://en.wikipedia.org/wiki/Bass_reflex

SWEET!.. . Reading material for to nights shift. Thanks @westmassguy

voltz

maximillian wrote: »

voltz wrote: »

Glad your with Bose and enjoying it and I am sure you can appreciate like many us his talent (Dave's) & that he gives advise freely so quickly to anyone needing help on the forum!

I personally don't know Dave's skills since I have never used him or know of his website. Kudos to him for his talent and service.

I joined club Polk in 2008 and went to work at Bose in 2014. My house is filled with Polks and now I am getting some Bose stuff. I have LSi setups for my Home theater and my living room for several years now. But I complemented my home with SoundTouch 10's which enable whole house audio over Wifi (that wasn't meant to be an advertisement :-p ). Oh yeah, I have acquired a few too many headphones too, but had Ultrafocus 8000's before I joined.

The biggest common denominator is that the people I work with love music. Most people are musicians to some degree. I love going to work and hearing music blasting from one of the sound rooms. It's a vibe that didn't exist when I worked for companies in other industries.

Cool that would be a sweet job I think. I have many Polk speakers myself and hve had several bose...M4's M10's CRS RTiA7's CSiA4's ..and had Bose 401's & acoustimass 10.1 or .2's still have some bose headset's for my kindle..

pic of what my 401's look like

HzTweaker

I wouldn't mind getting hands on a pair of clear 701s!

erniejade

I dj on the weekends and for most weddings I still use a Bose L1 original series from ...either 2004 or 2005. I can't remember. I knew several dj' s that used the pro version of the 901 with good results.

maximillian

Love the L1's. I used them once for an outdoor wedding. I'm not a DJ though but it was fun. Check out the F1's. They are amazingly loud and sound great.

Many people don't know about Bose's Pro line of products. We do make some big stuff. Below is one of my favorite videos. This company was tasked with installing the sound system for the main stadium. A couple of the guys in the video came to Mass to give a presentation of their work. It was cool to hear about it. This isn't a Bose marketing video, but one for the installers. There are many other videos for the Roommatch speakers out there if you are interested.

https://youtu.be/aNpE3leHTVg

westmassguy

maximillian wrote: »

Love the L1's. I used them once for an outdoor wedding. I'm not a DJ though but it was fun. Check out the F1's. They are amazingly loud and sound great.

Many people don't know about Bose's Pro line of products. We do make some big stuff. Below is one of my favorite videos. This company was tasked with installing the sound system for the main stadium. A couple of the guys in the video came to Mass to give a presentation of their work. It was cool to hear about it. This isn't a Bose marketing video, but one for the installers. There are many other videos for the Roommatch speakers out there if you are interested.

https://youtu.be/aNpE3leHTVg

Very cool. The Jonathan Livingston Seagull Theatre Sound System Competition essentially started the Pro Bose line, and dealers were reporting that musicians and small local bands were buying up 901s, turning them around for PA use.

lightman1

Mornin' Dave. Coffee?
I have series III 901. A little more TLC and they'll be up and running.

westmassguy

lightman1 wrote: »

Mornin' Dave. Coffee?
I have series III 901. A little more TLC and they'll be up and running.

Had two, that's my limit. Do you have the EQ?

lightman1

westmassguy wrote: »

lightman1 wrote: »

Mornin' Dave. Coffee?
I have series III 901. A little more TLC and they'll be up and running.

Had two, that's my limit. Do you have the EQ?

Not yet, buddy. This year long roadtrip is boogering up my fun time.

leftwinger57

Funny thing over at AK there seems to be a run of various series 901s being bought. Some of these guys never even knew there was an external EQ and they are not all series compatible with what series. Maybe because of the end of the run but check it out. Oh I did give Dave props and his web site saying business is not discussed here. Hope you land some customers Dave.. Waning under nom de plume or some fancy word meaning another screen name... lol

msg

Every once in a while, I find myself wondering about Bose speakers. One of my friends in high school had some 201s or 301s that he got from his older brother who was a Naval officer, and his stereo always sounded really good when we'd sit around listening to CDs and making tapes.

Never got a chance to check any out for myself. So many different models.

Which ones would be the ones to look into? It's a bit confusing, because some in a particular series weren't as good as others, as I recall when I last looked into them a little.

This would just be for 2ch fun. I think I'd like to try out some 901s.

@westmassguy - Dave, re: 901s, is there a particular series there that would be best desired? I saw that you have the Continentals. Not sure yet what difference those were, but seems like it was a special edition?

I do recall that you've said the EQ is very important to have for them.

Why does everyone hate Bose so much? This is a real question. I'm genuinely curious, and haven't had the opportunity to hear any for myself.

I've tried out a bunch of different brand headphones and headphone amps, for example, and while those all sound good in their own ways, my 2pr of different model Bose NC headphones are my favorites. Sound really good to me, no obvious deficiencies, comfortable, and easy to listen with for hours and hours.

nooshinjohn

I wonder how the phase plug mod would work with these….

plastic_avatar

nooshinjohn wrote: »

I wonder how the phase plug mod would work with these….

Well...

Possibly...

It might be a positive on the sole front driver.

It's not like they kept pushing the limits of the design, right?

Good idea.

I'm super curious what people do to them for mods now.

[goes to Google]

xschop

nooshinjohn wrote: »

I wonder how the phase plug mod would work with these….

You would never even get past the Dynamat mod to find out.

westmassguy

msg wrote: »

Every once in a while, I find myself wondering about Bose speakers. One of my friends in high school had some 201s or 301s that he got from his older brother who was a Naval officer, and his stereo always sounded really good when we'd sit around listening to CDs and making tapes.

Never got a chance to check any out for myself. So many different models.

Which ones would be the ones to look into? It's a bit confusing, because some in a particular series weren't as good as others, as I recall when I last looked into them a little.

This would just be for 2ch fun. I think I'd like to try out some 901s.

@westmassguy - Dave, re: 901s, is there a particular series there that would be best desired? I saw that you have the Continentals. Not sure yet what difference those were, but seems like it was a special edition?

I do recall that you've said the EQ is very important to have for them.

Why does everyone hate Bose so much? This is a real question. I'm genuinely curious, and haven't had the opportunity to hear any for myself.

I've tried out a bunch of different brand headphones and headphone amps, for example, and while those all sound good in their own ways, my 2pr of different model Bose NC headphones are my favorites. Sound really good to me, no obvious deficiencies, comfortable, and easy to listen with for hours and hours.

For conventional speakers, I'd recommend the 301 Series II or III bookshelf units. For floor standing I'd recommend the original 601s or the 601 Series III. All will most likely need to be re-edged, as the oeriginal polyurethane foam only lasted 10-15 years for most.
For 901s, my personal favorite is the Series II Continentals which I own. The 901 Original and Series II are acoustic suspension, and require plenty of good clean power. At over 50 years old, the Equalizers will need a recap at minimum. There are other upgrades that can be done to the Equalizers to improve the sound, but replacing all the electrolytics is manditiory.
901 Series III through VI are a proprietary bass reflex design that Bose calls Acoustic Matrix. They require less power for normal listening levels compared to the 1st two Series. My favorites are the Series IV with new cloth surrounds and rebuilt Equalizer, followed by late production Series VIs. Bose finally switched to treated cloth surrounds near the end of production, and the the Equalizers were very well made compared to earlier models.

xschop

Those 901 ports look like Polk's "new" bass port design with the integral bullet/cone.

mhardy6647

The original 901 series (those using the CTS "fullrange" drivers) were not ported, nor did they use ultra-low impedance drivers, as later 901 series did.




The earliest 901s also used nine drivers, with one forward-facing 4-1/2 inch "FR" CTS.
Hard to find a good period photo, but this from an eBAY auction will suffice.



I guess when it comes to phase plugs, the question is (i.e., should be) "What problem am I trying to solve?". The CTS fullrange drivers are quite nice sounding within their passband.


eBAY photo -- these drivers usually look a bit scroungy, but the sofa or chair in the photo is kind of scary looking!

Bose, of course, used prodigious amounts of outboard EQ to flatten the output of the 901.


source: https://retrovoltage.com/2012/07/25/bose-901-series-1-active-equalizer-repair-vintage-hi-fi/

Finally -- Besides the (in)famous Polk Audio Model 9/9A, Polk used these drivers (or very similar variants) in their adorbs little "MiniMonitor".




The above mentioned Bose 301 is a good sounding little loudspeaker (as was the 201). Both "get the midrange [quite] right".

SeleniumFalcon

There was the early '60's speaker system called "The Sweet Sixteen" that might have influenced Dr.B:

mhardy6647

Oh, a couple of more Bose-y things.

Prof. Bose's foray into evidence-based loudspeaker design wasn't all rainbows and unicorns.
His first effort (the 2201), although very rationally conceived, reputedly didn't sound all that good.




https://news.mit.edu/2013/obit-amar-bose-0712




https://1971.alumclass.mit.edu/s/1314/bp19/interior.aspx

Interestingly, his Cambridge neighbor , Henry Kloss, got his start with the Baruch-Lang loudspeaker, which was surprisingly similar in some respects to Bose's 901. Maybe not all that surprising -- the MIT roots in the genesis of modern loudspeaker design runs quite deep.


source: https://worldradiohistory.com/hd2/IDX-Consumer/Archive-Radio-Electronics-IDX/IDX/50s/1952/Radio-Electronics-1952-08-OCR-Page-0008.pdf



source: https://audiokarma.org/forums/index.php?threads/value-of-a-baruch-lang-speaker.479613/

EDIT: I thought it would be amusing if the drivers in the Baruch-Lang enclosure pictured above were CTS -- but they are in fact Carbonneau drivers (EIA code 719).

https://klhaudio.com/wp-content/uploads/2021/05/loudspeaker-design-hofmans-iron-law-by-henry-kloss.pdf
https://frank.pocnet.net/other/AWV_Radiotronics/Radiotronics_1954/1954_08_AWV_Radiotronics_19_08.pdf

westmassguy

xschop wrote: »

Those 901 ports look like Polk's "new" bass port design with the integral bullet/cone.

They were designed by an aerospace engineer, that's why they look like the business end of a 70s era jet engine. This design accelerated the air flow and reduced port noise.

mhardy6647

source: https://worldradiohistory.com/hd2/IDX-Audio/Archive-High-Fidelity-IDX/IDX/50s/High-Fidelity-1953-Jan-Feb-IDX-0093.pdf

40 Hz - 12 kHz, and no pesky crossovers!