If you have actual measurements of the distortion of a Bose 901 driver or it's equivalent replacement from Dayton then please show it. Otherwise, it's your own bias and conjecture. Most drivers will have linear response when driven under 1 mm - I can't imagine that this 4.25 in class full range driver will be that distorted. Here is the impedance curve and T/S parameters.
http://www.parts-express.com/pedocs/specs/290-922-parts-express-specifications.pdf
A quick simulation as a MLTL with 8 drivers will quickly reveal how much cone displacement is required to produce say 50 Hz of bass at moderate listening levels.
The blurb that claimed '2 or 3 mm' effective Xmax for the Bose 901 drivers also says that they are 'evenhung' topology. Of all topologies, that is the one with about the *minimal possible* Xmax for a given voice coil length - probably less than a millimeter for a small driver like the 901 type. Put another way, it's as close to 0mm in reality as you can come for that topology barring leakage flux and a 'standard' cutoff of 10% distortion.
An underhung woofer like the JBL 2220 with a VC length of 7.2mm and a gap length of 9.1mm is rated at 3.2mm Xmax, but it has 1.8mm of swing before the voice coil even begins to leave the gap, and the gap is much longer than for a 4" driver of the Bose variety so that the flux fall off is much slower when moving beyond Xmax.
IMO, drivers of the Bose type add bass harmonic coloration and start compressing HF information when pushed to play louder bass sounds.
An underhung woofer like the JBL 2220 with a VC length of 7.2mm and a gap length of 9.1mm is rated at 3.2mm Xmax, but it has 1.8mm of swing before the voice coil even begins to leave the gap, and the gap is much longer than for a 4" driver of the Bose variety so that the flux fall off is much slower when moving beyond Xmax.
IMO, drivers of the Bose type add bass harmonic coloration and start compressing HF information when pushed to play louder bass sounds.
8-driver Bipole MLTL with Bose 901 drivers
It looks like the Dayton replacement Bose 901 drivers can be used to make a MLTL with pretty high speaker sensitivity. The bass doesn't go particularly deep but that is really limitation of the fact that it is a 4 in driver with a relatively low Qts. The speaker cone displacement is pretty low at 1 watt, and may run into issues if pushed hard - although it is pretty loud at 1 watt 1 meter (96 to 97 dB).
Design is 10 in wide baffle x 16.5 in deep x 45 in tall, drivers mounted at 13.8 in from top with as tight C-T-C spacing as possible and wired in series to achieve 8 ohm impedance. Vent is bottom firing with 70 square inch CSA x 4 in long, standing on 3.5 in tall legs for bass to escape the bottom.
It looks like the Dayton replacement Bose 901 drivers can be used to make a MLTL with pretty high speaker sensitivity. The bass doesn't go particularly deep but that is really limitation of the fact that it is a 4 in driver with a relatively low Qts. The speaker cone displacement is pretty low at 1 watt, and may run into issues if pushed hard - although it is pretty loud at 1 watt 1 meter (96 to 97 dB).
Design is 10 in wide baffle x 16.5 in deep x 45 in tall, drivers mounted at 13.8 in from top with as tight C-T-C spacing as possible and wired in series to achieve 8 ohm impedance. Vent is bottom firing with 70 square inch CSA x 4 in long, standing on 3.5 in tall legs for bass to escape the bottom.
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I wouldn't say the 901 is a bad speaker, overall. Would it work as a studio monitor? Of course not. But for somebody with a moderate amount of acoustically not so good space for speakers who wanted something that could go fairly loud in that space and had the amplifier to manage it, it was definitely an option. But the 901 is idiosyncratic with its approach to generating an acoustic field and it use of active eq. For the 1970's both ideas were more unusual than they are now. The 901 could also handle a high power amplifier for those times without being destroyed or complaining too much (it had to, IAC for the bass eq to work out). The original Bose up to version 3 in particular which used eq to boost bass below 200hz had a response that was close to a classic 2nd order rolloff below that and which the eq box corrected down to 30-40 hz or so, so the bass and lower midrange were relatively non-resonant and suffered less from response deviations than most speakers did. This advantage was compromised to some extent, supposedly, when the ported version came out.
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Good Lord, a factual, non-opinonated post on an audio forum. 
The only possible error I see is that you probably mean "up to version 2": I think Bose went to ported starting at "III". I like the original Bose (series I & II) for the innovations you describe, as well as today we can easily buy (or build) much cheaper amp power and digital EQ that forty years ago didn't exist. Consider: my Behringer NU6000 + DEQ2496 together cost about $700 new. In 1974 dollars that might be $3500. Yes, they had powerful amps back then but that would have been most of your $3500.
The only possible error I see is that you probably mean "up to version 2": I think Bose went to ported starting at "III". I like the original Bose (series I & II) for the innovations you describe, as well as today we can easily buy (or build) much cheaper amp power and digital EQ that forty years ago didn't exist. Consider: my Behringer NU6000 + DEQ2496 together cost about $700 new. In 1974 dollars that might be $3500. Yes, they had powerful amps back then but that would have been most of your $3500.
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Agreed with all- one other point is that evenhung is the most efficient of the three arrangements, but only if you're hardly moving the cone assembly. Fine for well-implemented midranges etc, but not so much for anything playing below 300Hz.
My Wave radio doesn't.
Did a search, apparently they have a new version Wave lll. Looks like the touch top control is limited to on/off/snooze.
Certainly would be the case- think 901s use 4"s? 9 4"s.... approximately equivalent to a 12", so if a 12" can handle your required SPLs with hardly any excursion, you're good for keeping the motors relatively linear.
Have owned my 901 series 2's since the early 90's.
I'll take them over any speaker up to the same cost.
Why?" I play on stage and the 901's sound like the stage.
Live music there is no "stereo"
If your into a fake image and like "hearing the guitarist walk across the stage" then fine, but I have never seen a guitarist play a lead walking across the stage carrying his amp and speaker.
I'll take them over any speaker up to the same cost.
Why?" I play on stage and the 901's sound like the stage.
Live music there is no "stereo"
If your into a fake image and like "hearing the guitarist walk across the stage" then fine, but I have never seen a guitarist play a lead walking across the stage carrying his amp and speaker.
your spouting total nonsense. As someone who has stripped many speakers I see people drool over (they are worth more in pieces, amazingly) all speakers are cheaply made until you get into the grand each price range and most of that is just nice wood work wrapped around the cheapest driver they can find.
There are many well-made inexpensive speakers below 1k/per, and Bose is a very poor value. You don't seem to have much experience, no matter your claims. And do you really want to get into cheap drivers? That's one of the BIGGEST problems with bose. Just because you're in love with your purchase doesn't mean that they're amazing, or even good.
Your right, I have no experience Altec Lansings Models 7 & 9, Ohm's Walsh 2 that I owned and a set of Bose 501's before I bought my 901's..
Are all of those very cheap speakers in your opinion?
I have owned 3 pairs of older 301's. To this day I still re foam speakers so I get nice speakers in my garage quite often (set of C&W 15" woofers and a set of Pioneer 1100's in there right now) I also use woofer tester 3.
I have destroyed many consoles just for the speakers.
As for the 4" driver in the 901 Series 1 & 2 they were not made by bose.
You can find them in other sought after speakers like Fraizer.
(which used 4 per side)
Nice drivers for a 4" rated at 50watts, FS around 75hz and easily hit 12k, if you can find speakers that do that cheaply we all want to know where they are. I have bought several pairs of cheap 4" drivers off parts express and so far none have compared to the series 1 & 2 drivers.
You keep believing they are junk, it keeps the price lower for us.
The new 301's at $325 a pair are great sounding speakers for a small foot print 2 way 8" woofer.
As always speaker placement makes a huge difference as does room size, volume and material played.
Bose has the best marketing in the business, hands down. I am very interested in advertising and I give them full marks. I am also an Altec groupy and have heard most of the speakers you list.
The Altec 7 and 9 were brought out as something the common man could afford while still saying they had Altec speakers, nothing more. They aren't what Altec people talk about when discussing their speakers. They are very ordinary and were higher priced than they should have been.
I have only heard the Ohm speaker very briefly and cannot form an opinion.
The Bose 301 was a tricky little devil. Unless you put it up against a good speaker and did an A/B test, I can see why you might think they deserve merit.
The 501 was a sound I couldn't wrap my head around. It seemed like Bose wanted so bad to have one between the 301 and the 601 but that's the best they had time for. The 401 I never heard.
I have nothing bad to say about the Pioneers 1100's.
The 901, the flagship speaker I have utter admiration for and of course for the good Doctor. But why? Who in their right mind designs a speaker that makes very little sense from a design standpoint, that requires more EQ than is fair to your system? That's easy, they're sexy, damn sexy. If it weren't for that speaker I'd wager there would be no Bose today.
The Altec 7 and 9 were brought out as something the common man could afford while still saying they had Altec speakers, nothing more. They aren't what Altec people talk about when discussing their speakers. They are very ordinary and were higher priced than they should have been.
I have only heard the Ohm speaker very briefly and cannot form an opinion.
The Bose 301 was a tricky little devil. Unless you put it up against a good speaker and did an A/B test, I can see why you might think they deserve merit.
The 501 was a sound I couldn't wrap my head around. It seemed like Bose wanted so bad to have one between the 301 and the 601 but that's the best they had time for. The 401 I never heard.
I have nothing bad to say about the Pioneers 1100's.
The 901, the flagship speaker I have utter admiration for and of course for the good Doctor. But why? Who in their right mind designs a speaker that makes very little sense from a design standpoint, that requires more EQ than is fair to your system? That's easy, they're sexy, damn sexy. If it weren't for that speaker I'd wager there would be no Bose today.
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