The Bose 901

February 15, 2018
 by Paul McGowan

10 comments on “The Bose 901”

  1. I bought my first real speakers my sophomore year in college, 1975-1976, at Pacific Stereo in Berkeley. The saleswoman tried to sell me a pair of 901's, which were way out of my budget. We also didn't have an amp that could drive them. They did play really loud and we were duly impressed (by the loudness). I ended up buying a pair of JBL Century 100's, which gave me many years of good service (until I replaced them with Maggies). One of my college roommates is still happily using those JBLs.

  2. Bose speakers drive me from the room like fingernails on a chalkboard. I hear them as marketing scams foisted on the public by a team of mechanical engineers that don't know what music sounds like or how to characterize and optimize for it. I am convinced that they are bad for your hearing & health.

    The premises of the 901 design are FALSE. The impression of Bose 901 playing loud is largely due to DISTORTION. It has extremely high midrange efficiency, but ridiculous high frequency, low frequency, phase, spatial and Doppler distortion. Distortion is so intimately connected to public perception of loudness that I can upgrade to a system 10dB louder on an SPL meter but clean, and people will insist it is not as loud as the prior system clipping with 10% of the sound energy. James Johnston told this same story in an AES seminar - he had to add Germanium diode clipping to a PA system for his college dance parties.

    It is true that side wall reflections create the sound of a good "shoebox" hall (cf. Beranek "Music , Acoustics and Architecture"), but it is the precise reflections of eighty musicians in discrete locations for a concert hall that size, shape and architectural details. It does not translate to the side wall reflections of a pair of speakers in a rectangular residential listening rooms, which is spatial distortion. Even then, "90% room reflections" only work for lush orchestral scores and when there is a lot of diffusion so you can hear the direct sound at 10dB under the reverberations.

    The Schroeder limit (also called "critical distance") is the point where the reflected sound is equal to the direct sound (50% reflections), and generally considered the point where note definition declines. Past the 10th row in a good hall (and even in the third row in Geffen Hall or Met Opera), the sound loses articulation and intimacy because individual notes are swallowed by the excess reverberations. Chamber music in Tully or Carnegie Hall drives me crazy. OTOH, I get great sound for up to 50 seats in 2.5 to 5 meter wide rooms using floor to ceiling diffusers, usually media shelves covering both walls and designed to break up the reflected sound into wavelets.

    The second premise is using equalization. Since the response of drivers in non-linear and non-minimum phase, this exacerbates TEMPORAL DISTORTION with mangled spatial cues and mushy transients. The high frequency response of the bargain basement midrange drivers is determined by the interaction of non-linear parasitic inductance and cone breakup so it has a lot of narrow band hash.

    The third premise is using a lot of full range drivers. This means the bass frequency modulates the treble, producing frequencies not present in the original source. Paul Klipsch measured 901's at 110% inter-modulation distortion! This hurts my ears like an out-of-tune instrument, which of course it is.

    These lo-fi midrange drivers have high non-linear inductance and non-linear BL product with displacement which add distortion and the top and bottom end respectively. The array of 9 drivers beams and lobes high to mid frequencies, exaggerating room comb filtering effects and creating hot spots at different times, locations and frequencies.

    SO, every supposed feature is in fact a bug. Anticipating the software industry, they documented their bugs to make them features, proving that people buy stories, not products. This story deserves an award in the "Fantastic Fiction" category.

    1. The 901s eq box was doing some sort of weird stuff to the sound. There are huge alterations to the lower and higher frequencies. I had them for years, and when I switched to the ratshack's two ways with the linaeum (not sure how to spell) they didn't sound right. A borrowed pair of 3 ways also didn't sound right. I had becomed 'trained' to their sound, it took me about a month to de-program my ears and brain. Whatever radical eq they used, was playing tricks on my, and other's ear/brain functions. Purchased @ Pacific Stereo @ Harlem& Narraganset, Chicago.

      1. Yes, they "broke-in" your brain, so you have to work to "break out" of this box.

        Thumbs up for Linaeum tweeter, too bad Radio Shaft never gave them a good enough dipole midrange.

  3. If I ever heard someone demonstrating speakers too loud, I too would walk away. Back in 1975, I went to Pacific Stereo to audition some JBL L65s. I wanted some West coast sound, as I had AR4s. Advertisement looked impressive. I also had my BS&T test record track. Ended up, the L65s were just too bright, even with controls down. I was listening to L100s, and L200s, and Bose 901 series IIs. I got a blah impression from L100s. Perhaps I listened to 901s next. OK, I loved the overall sound and imaging. It was right. Next up L200. Sounded very good. They were really far apart. I would say I liked them really well, but at 4 times the price, were out of my range. The 901 was an easy choice. Took them home to my small apartment where I thought they sounded great, sitting just a few feet away. Funny, I later visted Pacific Stereo, and the same salsman was demonstrating the 901 without Eq attached. It was a process. I just thought to myself without saying anything.

    Years later, fooling with friends 901 series IV, i noticed a certain hollowness to the sound, and a tinging, and a low bass hootiness. I preferred the sound of the series II. The series IV was definately more efficient though. I am well aware of issues after much experimentation with them. Lack of internal damping I thought was one problem of the plastic matrixes. Never heard later models, but they had certain improvements, including long lasting foam surrounds. Series I and II had ever lasting cloth surrounds. Later years I got into building various speakers, but the 901s are still in the family somewhere.

  4. My issue with Bose isn't so much the 901, but on a system we had in one of our cars. The Bose was of course touted as a "premium" system, but my ears told me much different. That same type of heavy equalization used in the 901 was also applied in the car system. The speakers at all four corners were pretty much along the lines of the same paper-coned full range drivers used in the 901, and the car's EQ was forcing those pathetic little things to reproduce frequencies they were not meant to reproduce. It might have been OK when the volume was low but when I would turn it up, I could hear a lot of intermodulation and Doppler distortion--it reminded me of really poorly encoded MP3 files with that "warbly" sound tainting all of it. The highs were *there* but they were never *clean* like you would get with a separate tweeter. Any appreciable amount of mid-bass muddied up the mids and highs. The only clever thing the system had was an eight inch flat "pancake" woofer in the rear deck. It worked well enough, but it was no match for any subwoofer I had ever used in a car before.

    1. I have Bose in my truck. Overall, much better than typical OEM. It has tweeters too, sub, and 4 door speakers. Must have sensing as you cant distort with volume. The sound is diffuse, no real imaging. I would have to modify to get the sound I desire. My Subaru sound is yuk, but it does have a 4 inch subwoofer LOL.

      1. In another car (which did not have a Bose system), I made a change last April. I put in a system with a touchscreen Pioneer head unit which has the capability of playing high-res files up to 24-bit/192kHz from both SD cards or USB flash drives, and also offers built-in EQ and time delay circuitry (where you enter the distance from each speaker to the driver's seat). I used a small Kenwood class D amp which tucked easily behind the dash, and component Morel speakers for the fronts (as I have a separate factory tweeter location) and coaxial Morels for the rear doors. The back end started with a "spare tire" Pioneer sub (which I had to order from the UK), but that didn't cut it--I later bought a small powered Focal BombA BP20 sub (8" woofer, class D amp).

        It is one of my better-sounding systems (with that time delay making more of a difference than I thought it would--it really locks the sound in nicely), but I also realized it's one of my last. Few if any newer cars have double-DIN capabilities. And, these old bones aren't flexible like they used to be--I never remember it being this physically exhausting acting as both gymnast and contortionist! If the neighbors had heard me, they would have sent for the white Tourette's van to pick me up... ;o)

  5. That is why Bose no longer makes the 901's. In fact Bose no longer sells really any stereo speakers anymore except for the 201/301 series which are low end. Their focus is now on headphones/ear buds (yes I own a pair of the bluetooth wireless buds for working out and they aren't bad for that purpose and are sweat resistant) wireless speakers, etc. I don't see Bose as high end audio and never have. Are they over priced, to a degree but I do own the Bose Soundlink Color 2 which is a decent background music player while I'm cooking or have family/friends over. My Father, god bless him, says the Bose speakers were the best he's ever owned (he had a pair of EMI's from Arrow Electronics with a Kenwood receiver back in the "day") in terms of clarity he's heard. I had him listen to some higher end bookshelf speakers and he still thought the Bose were better (I tried). Again audio is such a personal choice and is very subjective.

    Leads me to Paul's point ...there are some people that just don't give a rats ass about high end audio which is fine. I think a bigger problem is how high end audio is presented to consumers. Take the headphone/ear bud market for example. There is a shit ton of products out on the market and the only way to really try any of them is to buy them and experience it yourself. For the average consumer who is not an audio enthusiast it can be mind boggling which either causes them to just buy whatever the Best Buy guys recommends to get it over with or has them turning away all together which is not a good way to get them into better sound.

    1. Short of trusting reviews at HeadFi, I agree there is no good way to compare headphones, ear buds, etc. At the audio show I have access to (AXPONA), they have a room where the headphone vendors set up. But even there, this isn't a place where you will find entry-level headphones--these are systems that likely also use a separate DAC and headphone amplifier in addition to a source. I don't know how dedicated headphone shows operate (like CanJam) but I see value in displaying at least a small number of the lower-priced products even if only to give us something to recommend our non-audiophile family and friends.

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