NSB 901's?

[MPM]

Has anyone considered doing a Bose 901 type speaker with the PE buyout "NSB" speaker? Is it worth while? I'm not a big fan of Bose but the 901's can be pretty impressive when properly setup. I might try it later just for the heck of it, I just hope the Bose lawyers don't come after me for thinking about doing this.

[rcavictim]

Great idea. I hope you try it and report back. Don't worry about being sued, your product will be sufficiently different....you won't be using dry rot surround drivers. The NSB's may not have the power handling necessary though to give enough bass though. IIRC the Bose had quite a bass boost in the supplied equalizer needed to be run with these speakers.

[MPM]

Originally posted by rcavictim
your product will be sufficiently different....you won't be using dry rot surround drivers.

LOL


I'll probably make an equally inxpensive sub setup if the NSB 901's turn out to be usable but only lacking in the bottom end. I'll call it my J-Lo config. Pretty good top end but with an enhanced bottom end.

[cjd]

The biggest limitation on the bass will actually be partly the fault of the box size. They like a pretty big box.

My suggestion would be to do a 2.5-ish way design - single NSB supplemented by one of the $.69 Onkyo buyout tweeters (3 component crossover is do-able) on the front, and 8 NSBs on the back to boost the bottom end - wire for 16ohms I think. Separate enclosure for the single NSB.

A single NSB + buyout tweeter (Audax) in an open baffle with lots of bass boost sounds very good (much better than a pair of $9 speakers should sound), though it is easy to hear when it gets pushed past xmax (detail disappears). They're pretty robust drivers, and if your low end isn't trying to reproduce much in the way of detail, I think you could definitely get away with it.

C

[MPM]

cjd - It crossed my mind that I could incorporate a tweeter in it somewhere. But, in my mind I wanted to keep it simple as far as a crossover is concerned. I can build an ok cabinet but making a crossover is much more difficult for me.

Now that I think more about it, using 8 drivers on the back is overkill if I'm going to use a separate woofer w/amp. Maybe use 4 NSB's(2 per side instead of 4) in a narrower version of the 901's layout with a single NSB/tweeter on the front.

Any feed back is appreciated. For that matter, any suggestions on the internal volumes I need for this speaker is appreciated.

[cjd]

I use these drivers in my HT at the moment - MMTMM in the front and MTM in the back. Crossed at 100hz. The boxes up front are ~1.2 cubic feet, ported and stuffed.

A pair of the NSBs looks really good in a 48" tapered pipe (taper from 0 to 2Sd, port 2" dia, 2" long, drivers near the middle or slightly above).

Yes, these drivers like volume in the enclosure.

If you build them with the possibility of a 3-way in mind (active crossing to a woofer counts) then you can look at box tuning to work with this and find a smaller enclosure suitable.

These are, in my opinion, great drivers to learn on. Cheap, and they *can* sound surprisingly good when you get it right.

C

[Bose(o)]

I've got my Dad's 901s handy and quite a bit of info on the 901s if you want. I'm interested on your results. Please report back.

[MPM]

Originally posted by cjd
I use these drivers in my HT at the moment - MMTMM in the front and MTM in the back. Crossed at 100hz. The boxes up front are ~1.2 cubic feet, ported and stuffed.

C

Care to share your crossover? Making(much less designing/building) a crossover is my weakest point. From my limited knowledge I can't imagine the crossover I might need being very different from yours provided I use the same tweeter and a separate sub woofer.

Originally posted by Bose(o)
I've got my Dad's 901s handy and quite a bit of info on the 901s if you want. I'm interested on your results. Please report back.

I'd like to know the width of the entire cabinet and the individual width of each back panel. This will let me figure out the angle the two back panels are at.

[cjd]

I can help with crossover, but you are going to get a very different response out of this system than I have tools to model so it may be, well... a bit of trial and error. The 4" drivers like being crossed high, so your key frequencies will all be from any drivers on the front, not the array. Reflections will help only a little past a certain point, and room setup will vary which frequencies. Sounds like a list of all the problems people had with the 901s.

send me an e-mail - chris at eldamar dot net

also, baffle dimensions may be useful. I have it in mind that you may end up with a slightly different variation than the traditional Bose layout, but we may find something that sounds quite good for the investment. Not to mention the fun.

C

[MPM]

Here are the speaker specs. To simplify the construction of my 901 look-a-likes I'd like to start with a sealed enclosure but I'm not sure if that will work. What will the speakers do if put into a cabinet with an internal volume of 980 cubic inches? If I build these I will eventually have a separate powered sub. Have also decided to skip the tweeter for now and see how they come out without it. More than likely these will end up in my garage or work shop provided they don't sound like complete a$$.

Fs 104 Hz
Qms 5.021
Vas 3.27 L
Cms 0.721
Mms 3.2 g
Rms 0.421 kg/s
Xmax 1 mm
P-Diam 84.85 mm
P-Vd 0.00565 L
Qes 0.915
Re 6.9 ohms
Le 0.58 mH
Z 8.3 ohms
BL 4.0 Tm
Qts 0.774
1-watt SPL/m 88 dB

None of my ramblings are set in stone so if anyone has a suggestion please let me know. Porting suggestions or BSC recommendations, stop while your ahead, etc..............................