Bose 901 Series V Speaker Review!

[audioresearch]

I believe the distortion was high because the speakers you tested were old and most likely the spiders, and/or surrounds, and/or cones had deteriorated with age.

In the case of the surrounds, it is a known fact that the foam surrounds would often completely rot away with age and quite likely the ones in the speakers you tested were well on the way to failing totally. I believe that somewhere in the production run of the series V, the foam was changed to a different type of foam that would not rot.

Those problems would likely also affect the frequency response.

I have no idea how much the old foam surrounds contributed to the high distortion numbers, but at least the first two editions of the 901 (original 901 and series II 901) did not have the foam rot problem because they did not use foam, so perhaps they will have much better distortion numbers and maybe even frequency response also if you are able to test them one day.

I used to run 4 pairs of 901s which really took care of any limited output capabilities quite nicely at least until the day when all their drivers failed due to foam rot.

Nobody ever mentions one fantastic improvement made by the 901s: finally, at long last, a speaker system where blowing tweeters is not a problem when listening to loud music.

 

[audioresearch]

Let me add that it is nice to know old 901s can probably deteriorate a lot, at least the ones with foam surrounds one series of which you tested and so if your tests are representative of all Bose speakers that used the original style of foam(see what follows about that) then maybe one would wish to avoid buying used series 3-5. I'm not sure about the series VI original or series VI updated. I heard from a highly placed engineering source at Bose whom I personally knew that once the foam rot problem became known, Bose switched to a foam with a different molecular structure that supposedly would not rot somewhere during the production run of the series V and so the series VI should supposedly have the newer "good" foam.

 

[GXAlan]

If you look at my signature, I have done some non NFS basic measurements of the VI, VI ver 2 and original 1968 model.

 

[Everett T]

I believe the distortion was high because the speakers you tested were old and most likely the spiders, and/or surrounds, and/or cones had deteriorated with age.

In the case of the surrounds, it is a known fact that the foam surrounds would often completely rot away with age and quite likely the ones in the speakers you tested were well on the way to failing totally. I believe that somewhere in the production run of the series V, the foam was changed to a different type of foam that would not rot.

Those problems would likely also affect the frequency response.

I have no idea how much the old foam surrounds contributed to the high distortion numbers, but at least the first two editions of the 901 (original 901 and series II 901) did not have the foam rot problem because they did not use foam, so perhaps they will have much better distortion numbers and maybe even frequency response also if you are able to test them one day.

I used to run 4 pairs of 901s which really took care of any limited output capabilities quite nicely at least until the day when all their drivers failed due to foam rot.

Nobody ever mentions one fantastic improvement made by the 901s: finally, at long last, a speaker system where blowing tweeters is not a problem when listening to loud music.

From the review: "Funny side story: he was going to send the Series IV he owned but had issues when it came time to refoam them so he sourced a very good condition pair of Series V’s and shipped them to me."

So the surrounds were not an issue with the measurements FWIW.

 

[audioresearch]

From the review: "Funny side story: he was going to send the Series IV he owned but had issues when it came time to refoam them so he sourced a very good condition pair of Series V’s and shipped them to me."

So the surrounds were not an issue with the measurements FWIW.

Ya maybe, I was just guessing. But it does seem that old speakers can age differently from speaker to speaker so it might be best to test a few pairs if ever you have that luxury. In the last year, I bought 2 pairs of original 901s and at least one of the drivers seems bad as I can hear serious distortion/rubbing/whatever from one particular location on one of the speakers. I have a spare original 901 and whenever I get around to it, I'll narrow down the problem to whichever driver(s) is the cause and replace it and also check the state of the sealer around the drivers and also clean up the connections where the internal wiring attaches to the internal speaker terminals that are on the bottom of the cabinet since in the past I have found those to sometimes be corroded enough to badly ruin the sound.

 

[ahofer]

An acquaintance is staying in a place on Long Island. Sent this pic

Place is owned by a well-known electronic musician.
Another pair of 901s in the closet, apparently.

 

[egellings]

I just have a problem with a 4" or so diameter paper cone doing justice to frequencies usually reproduced with small dome or ribbon drivers. I can see how 9 of the drivers could cover bass & midrange frequencies adequately, however. I heard a pair once and was impressed by how good the LF performance was, and midrange did well, too. HF output, not so good, despite the EQ provided with the speakers.

 

[GXAlan]

An acquaintance is staying in a place on Long Island. Sent this pic

Place is owned by a well-known electronic musician.
Another pair of 901s in the closet, apparently.

Nice! If I just saw one, it would have been chosen for looks. With a second pair, the musician must really enjoy the sound.

I just have a problem with a 4" or so diameter paper cone doing justice to frequencies usually reproduced with small dome or ribbon drivers. I can see how 9 of the drivers could cover bass & midrange frequencies adequately, however. I heard a pair once and was impressed by how good the LF performance was, and midrange did well, too. HF output, not so good, despite the EQ provided with the speakers.

It very clearly drops above 16 kHz, which makes it less ideal when you are younger but less of an issue as you get older. It does give a bit of a vinyl/less detailed and less fatiguing sound.

That said, I have MG-III’s and multiple generations of the EMIT tweeter. The 901’s are still an enjoyable speaker. Adding a super tweeter to fill the upper most octaves works great. I have used the JBL UT-405 with my Bose 901’s and gotten great results.

 

[egellings]

Nice! If I just saw one, it would have been chosen for looks. With a second pair, the musician must really enjoy the sound.


It very clearly drops above 16 kHz, which makes it less ideal when you are younger but less of an issue as you get older. It does give a bit of a vinyl/less detailed and less fatiguing sound.

That said, I have MG-III’s and multiple generations of the EMIT tweeter. The 901’s are still an enjoyable speaker. Adding a super tweeter to fill the upper most octaves works great. I have used the JBL UT-405 with my Bose 901’s and gotten great results.

I did like the room filling effect of the speakers on some music. On other music, the effect seems overblown.

 

[GXAlan]

I did like the room filling effect of the speakers on some music. On other music, the effect seems overblown.

It's definitely not your "girl-with-guitar" speaker choice. It really does work great with anything you'd hear in a concert hall, or a "big band" type of sound.

In my home, I've found them to be exceptional for my home theater since the high frequency roll off isn't a big issue. I should have ridiculous amounts of comb filtering, but I don't think it matters in practice. I have four Bose 901 running at L/R front + rear. I have two JBL S/2600's flanking the television as my dual center channel. That has the asymmetrical horns which preserved a center image for vocals even when you are silly-off-axis.

I feel like it's the difference between listening to headphones vs. speakers and speakers vs. the 901 room-filling sound.