Bose 901 Series V Speaker Review!

[tomtoo]

I should have kept my 901 SII. Hungry for power, but perfect for blasting a room full of people! With two 12" subs crossed at 100 Hz quite good, although not of critical listening. Plus not power hungry at all

Ah and THANKS! for your measurments!

Thats what i thought of. Two of them with two subs. Amp them with a PA amp. They can fill a party room easaly.
They can fill the room with sound whats somehow cool. And at a party who cares about little tonal problems and soundstage at the optimal triangel??

 

[pozz]

For those interested, the 901 is discussed in passing in:

• (1996) Amar Bose - Experiences of an Academician in Industry
• (1995) Amar Bose - Acoustics (full lecture series)

In the lecture series, one of the sessions goes into detail about the math used to balance reflections.

 

[thewas]

Thats what i thought of. Two of them with two subs. Amp them with a PA amp. They can fill a party room easaly.

In this case you could also turn them with their rear to the front for more direct sound which makes them similar to their PA sibling, the 802:

Source: https://assets.bose.com/content/dam...hnical_datasheet/tds_Panaray_802_SeriesIV.pdf

 

[hardisj]

In this case you could also turn them with their rear to the front for more direct sound which makes them similar to their PA sibling, the 802:

View attachment 74791

Source: https://assets.bose.com/content/dam...hnical_datasheet/tds_Panaray_802_SeriesIV.pdf

I love the idea of putting DI in to "Q". I understand Q much more intuitively than I do DI.

 

[tomtoo]

In this case you could also turn them with their rear to the front for more direct sound which makes them similar to their PA sibling, the 802:

View attachment 74791

Source: https://assets.bose.com/content/dam...hnical_datasheet/tds_Panaray_802_SeriesIV.pdf

You could, but maybe it's not that bad to have a lot of indirect soundpower. Makes the SPL and sound in the room more homogen?

You know just thought about a typical party basement we have in germany. A 2502 and two subs. And how we would say in germany "Die Lutzi kann abgehen".

 

[thewas]

Guess would depend on the room acoustics, how many of those 901 you have and how many people are in the room (and how many sound absorbing clothes they still wear )

 

[tomtoo]

Guess would depend on the room acoustics, how many of those 901 you have and how many people are in the room (and how many sound absorbing clothes they still wear )

HaHa a fu** lot of parameters you have to take into calculation. But if the math is wrong you still can try to rotate them.

 

[tuga]

Man, I ain't about to spend time blurring that many pictures. The front wall is at least 20 feet long and all but maybe 4.5 feet is bookshelf from 3 feet to about 9 feet high with everything my wife could put on them.


Of course, if people keep refusing to effing read and instead make knee-jerk comments about the setup in the upstairs room then I may have to. Or just take the pictures of my listening space down. I have to keep replying "did you read the review?".

Just blurr the whole wall.

 

[hardisj]

Just blurr the whole wall.

I'd like to tear down the whole wall... but that's a different story...

 

[NoAudiophile]

I know the 901's can lack clarity, but I am curious about the distortion measurements and listening impressions. Is the distortion possibly from the age of the speakers? This being the Series V means the speaker drivers are at least 34 years old. The electronics in the EQ box is also at least 34 years old, that is way past the service life on those caps. I've spent plenty of time with various pairs of 901's, and while they do shit the bed in many ways, they should be able to do a 80-20kHz sweep without massive distortion issues.

 

[hardisj]

I know the 901's can lack clarity, but I am curious about the distortion measurements and listening impressions. Is the distortion possibly from the age of the speakers? This being the Series V means the speaker drivers are at least 34 years old. The electronics in the EQ box is also at least 34 years old, that is way past the service life on those caps. I've spent plenty of time with various pairs of 901's, and while they do shit the bed in many ways, they should be able to do a 80-20kHz sweep without massive distortion issues.

The EQ was not in-line in one of the tests so the distortion wouldn't be caused solely by that.

The drivers do not exhibit any audible popping/clicking and the impedance sweep shows nothing that would indicate it (or was audible at 2.83v).

From what I've read, others have commented about the high distortion of the drivers. I found this one, in particular:
https://www.psaudio.com/askpaul/the-bose-901/

"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."

 

[NoAudiophile]

The drivers do not exhibit any audible popping/clicking and the impedance sweep shows nothing that would indicate it (or was audible at 2.83v).

I have an SPL meter, and I know what distortion sounds like. If you say the EQ was not used and the drivers were in good shape, then I'm trying to figure out what the measurement picked up as distortion. Is it possible that combing was picked up as distortion, or that the measurement did not pick up the rear speakers as loud as they actually are due to Inverse Square style proximity losses of pointing the mic at the front speaker nearfield?

I don't take anything Paul from PS Audio says as truth, the fact that he said it actually makes it suspect.

 

[tomtoo]

The perfect party speaker for us elder.
When we come into sentimental mode, we like to listen to hells bells. And to at least 10% thd in the beginning of that Song we are just used to.

 

[617]

https://www.parts-express.com/replacement-speaker-driver-for-bose-901-4-1-2-1-ohm--290-922

Replacement driver for the 901 - just to see what we're working with here. FS of 83hz.

FR: https://www.parts-express.com/pedocs/brochures/290-922-parts-express-brochure.JPG

Seems like a well designed driver for the time, but we can do much better nowadays.

 

[hardisj]

I have an SPL meter, and I know what distortion sounds like. If you say the EQ was not used and the drivers were in good shape, then I'm trying to figure out what the measurement picked up as distortion. Is it possible that combing was picked up as distortion, or that the measurement did not pick up the rear speakers as loud as they actually are due to Inverse Square style proximity losses of pointing the mic at the front speaker nearfield?

I don't take anything Paul from PS Audio says as truth, the fact that he said it actually makes it suspect.

What I am saying is:
An impedance sweep should show rubb & buzz (mechanical issues) that would cause high distortion. I didn't observe that in my measurements.

I heard audible distortion in my subjective evaluations which were conducted before objective measurements.

It's possible the unique nature of this speaker makes the distortion appear higher than it actually is. Though, I believe the data is showing me the truth. I recently tested a speaker that exhibited audible distortion in the midrange and measured under 5% there. This speaker's distortion was considerably more noticeable.

Aside from that, the compression is measured as a SPL output vs voltage in. The compression is very high for this speaker as well.

Based on my experience measuring raw drivers, these results indicate a crappy drive unit.


The quote was not from Paul (I agree). It was from a commenter.

 

[NoAudiophile]

It's possible the unique nature of this speaker makes the distortion appear higher than it actually is. Though, I believe the data is showing me the truth. I recently tested a speaker that exhibited audible distortion in the midrange and measured under 5% there. This speaker's distortion was considerably more noticeable.

If you measured SPL from the front of the speaker for the distortion test, then you can add 15dB for the rear to that SPL based on your off axis information. It measures under 5% distortion with the front putting out 82dB, the rear is blasting at 97dB - in a highly reflective environment the listener will hear the 97dB minus whatever proximity losses occur from the rear wall bounce. I'm not sure what your data for other speakers looks like, but I'm guessing 97dB would be a pretty good or average result for a distortion test like this.

 

[NoAudiophile]

Replacement driver for the 901 - just to see what we're working with here. FS of 83hz.

Looking at the impedance graph measured by Erin it appears the drivers in this speaker have an FS of around 130Hz, unless there is some goofy wiring going on inside the box outside of ganging the drivers to reach the desired load.

 

[MarsianC#]

Drivers are super low impendace as all are connected in a row, very unsual. Bose at its finest, i guess.

Erin, can you measure a driver on its on?

 

[hardisj]

If you measured SPL from the front of the speaker for the distortion test, then you can add 15dB for the rear to that SPL based on your off axis information. It measures under 5% distortion with the front putting out 82dB, the rear is blasting at 97dB - in a highly reflective environment the listener will hear the 97dB minus whatever proximity losses occur from the rear wall bounce. I'm not sure what your data for other speakers looks like, but I'm guessing 97dB would be a pretty good or average result for a distortion test like this.

If we go off the assumption that I am indeed only capturing the HD of the front speaker then I can tell you that I have seen and tested numerous 4 inch drive units without this high level of distortion in the 500Hz+ region. Even at 2.83v the midrange distortion is over 1% THD.

Aside from the objective data, I noted in my subjective evaluation that the distortion was noticeable and limited the SPL to the mid 90’s at my listening position. Comparing these results objectively and subjectively, the results are in line with what I heard from other speakers I have recently reviewed.

 

[Xulonn]

I assume that Bose no longer sues reviewers who say bad things about their products.

This review is an interesting exercise, and a nice subjective plus objective overview of a very controversial speaker. Amar Bose's contention that live music is 90% reflected sound made sense with my experiences at Davies Symphony Hall listening to the San Francisco Symphony Hall, but not with a 1978 punk rock band at Mabuhay Gardens on Broadway in SF with a stack of Marshall speakers stacked eight feet high against that small club's back wall - or with acoustic guitar played outside in a garden setting.

Back in the late 1970's, a friend had the Bose 901s and a Sansui receiver, but I very much preferred my pair of Honkers Sound Company (Berkeley Mac and JBL dealer) 16 cu.ft. custom bass reflex speakers with the JBL S8 (LE15A woofer, 378 midrange and 075 tweeter) drivers. At the time, I had McIntosh Mac1900 receiver rather than separate components, but 50wpc was enough for the JBLs.