After purchasing a used pair of Nautilus 801:s I've thought on what would happen if I replaced the mids with Accuton C173-6-191E! 
I thought it might interest others so here are some pictures...
First out with the drivers, It had some "soft" loc-tite, no problem to unscrew them!
Then finding a suitable way to fix the C173:s. A standard pulling tool turned out to be useful. The magnet makes the arms stay in place. And a threaded bar M6 and some nuts did the rest.
The diameter of the C173 is about 2mm too big unfortunately. I made a thick foam gasket that is pressed when mounting the driver. I might use a lathe to take down the diameter slightly.
Then some measuring and tweaking in the crossover. I made a new separate one for the m/t. The bass/mid is crossed with active crossover.
I needed to raise the output from the C173 at its low end. For this I use a Nanodigi from Minidsp. I also played around with the B/M crossover frequency. Lowered it a bit to 250Hz.
I must say the I beg your pardon to the people in Worthing, but I really enjoy the new view of the speaker (and the sound😀)
I hope it can inspire some to try it out!
I thought it might interest others so here are some pictures...
First out with the drivers, It had some "soft" loc-tite, no problem to unscrew them!
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
Then finding a suitable way to fix the C173:s. A standard pulling tool turned out to be useful. The magnet makes the arms stay in place. And a threaded bar M6 and some nuts did the rest.
An externally hosted image should be here but it was not working when we last tested it.
The diameter of the C173 is about 2mm too big unfortunately. I made a thick foam gasket that is pressed when mounting the driver. I might use a lathe to take down the diameter slightly.
Then some measuring and tweaking in the crossover. I made a new separate one for the m/t. The bass/mid is crossed with active crossover.
An externally hosted image should be here but it was not working when we last tested it.
I needed to raise the output from the C173 at its low end. For this I use a Nanodigi from Minidsp. I also played around with the B/M crossover frequency. Lowered it a bit to 250Hz.
I must say the I beg your pardon to the people in Worthing, but I really enjoy the new view of the speaker (and the sound😀)
An externally hosted image should be here but it was not working when we last tested it.
I hope it can inspire some to try it out!
While you can do that, if I remember correctly the midrange in those speakers is already ridiculously good so I don't think it would be an improvement. The Accutons doesn't have a phase plug either so you wont have as graceful off axis response.
There is an aerodynamic piece mounted behind the midrange inside each mid cabinet? Very interesting...
I believe the phase-plug is just one criteria influencing the sound. My experience is that the off-axis response is better than before. More open and live sounding in off-axis places. I did some measurments off-axis as well.
The impulse response of the C173 is great compared to the original mids!
But I also like the B&W mids - but they don't sound like the C173:s!
The really good thing about the speaker is the mid housing (and the speaker as whole), and that I can't copy as a DIY:er!
Anyway - I don't mean to offend people who likes the midrange of the B&W:s. If anyone who thinks it's ridiculously good - don't change it!😉
The impulse response of the C173 is great compared to the original mids!
But I also like the B&W mids - but they don't sound like the C173:s!
The really good thing about the speaker is the mid housing (and the speaker as whole), and that I can't copy as a DIY:er!
Anyway - I don't mean to offend people who likes the midrange of the B&W:s. If anyone who thinks it's ridiculously good - don't change it!😉
I am very interested in off axis and very off axis measurements between 1KHz an 5 KHz.
I would think that the 4 KHz (?) crossover frequency is at least an oktave too high for such a large mid driver.
Maybe the nice enclosure does miracles there. The Stereophile measurements look ok.
I would think that the 4 KHz (?) crossover frequency is at least an oktave too high for such a large mid driver.
Maybe the nice enclosure does miracles there. The Stereophile measurements look ok.
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Here are some measurments I did today.
All made on height with midrange center. Distance about 60cm. I have an approx delay of 2ms in the Nanodigi - thats why offset is 4ms.
First on-axis
Then off-axis ~30 degrees
Then off-axis ~60 deg (forgot to save the step answer...)
What interesting is that the peaks on 2k8 and 4k2 that you see clearly in the on-axis measurment can be seen on each individual driver as well. See here:
So it comes from the housing - or?
The midrange is not "countersunk", it rests with its frame on the housing (as the mid diameter is slightly big) - could that be an explanation?
All made on height with midrange center. Distance about 60cm. I have an approx delay of 2ms in the Nanodigi - thats why offset is 4ms.
First on-axis
An externally hosted image should be here but it was not working when we last tested it.
Then off-axis ~30 degrees
An externally hosted image should be here but it was not working when we last tested it.
Then off-axis ~60 deg (forgot to save the step answer...)
An externally hosted image should be here but it was not working when we last tested it.
What interesting is that the peaks on 2k8 and 4k2 that you see clearly in the on-axis measurment can be seen on each individual driver as well. See here:
An externally hosted image should be here but it was not working when we last tested it.
So it comes from the housing - or?
The midrange is not "countersunk", it rests with its frame on the housing (as the mid diameter is slightly big) - could that be an explanation?
Hi,
Whilst the sound might be different it is highly
unlikely to be better overall with a changed driver.
Especially a driver with very diffrent cone technology
that can't possibly work the same way as the original,
without some crossover modifications at the very least.
There are some measuremnts of a B&W FST mid here :
Zaph|Audio
rgds, sreten.
Whilst the sound might be different it is highly
unlikely to be better overall with a changed driver.
Especially a driver with very diffrent cone technology
that can't possibly work the same way as the original,
without some crossover modifications at the very least.
There are some measuremnts of a B&W FST mid here :
Zaph|Audio
rgds, sreten.
The 2.8 and 4.2 khz bumbs could be midrange driver resonances or diffraction effects or suboptimal driver blending.
Perhaps there are other measurements of this driver somewhere?
Perhaps you can also look at the unfiltered midrange.
From these measurements i would think that your Accuton midrange driver is a bit too loud compared with the tweeter.
Perhaps there are other measurements of this driver somewhere?
Perhaps you can also look at the unfiltered midrange.
From these measurements i would think that your Accuton midrange driver is a bit too loud compared with the tweeter.
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The levels have been adjusted in the Nanodigi. Without compensation the mid has too low efficiency compared to the old mid. I also have to increase output in the lower range of the mid.
I found an interesting thing! If I put felt on the midrange edge, the tweeter measurment looks much nicer. Then I don't see the bumbs!
So I have to take down the diameter of the mid, making it fit better in the housing!
I'll post some new measurment once done!🙂
I found an interesting thing! If I put felt on the midrange edge, the tweeter measurment looks much nicer. Then I don't see the bumbs!
So I have to take down the diameter of the mid, making it fit better in the housing!
I'll post some new measurment once done!🙂
Thought I would give this thread an update.
To make the C173 fit nicely in the mid-housing I put the drivers in a friends turning-machine? I tried to cover it as good as possible and everything went well🙂 Taking off a couple of mm on the diameter.
I played with the standard tweeter for some time, but finally decided to go for a Accuton CELL C30-6-358. You have to try to know what it does - right?
This caused of course crossover changes and to be honest it took quite some time to find the design I have today. I tried mainly lower crossover points but it all fell into place when I decided to go for a 6dB filter, with impedance and resonance compensation circuits. Moving the tweeter in line with mids did the final magic
Right now I'm in that phase "don't change anything" which normally lasts for a couple of months!
To make the C173 fit nicely in the mid-housing I put the drivers in a friends turning-machine? I tried to cover it as good as possible and everything went well🙂 Taking off a couple of mm on the diameter.
An externally hosted image should be here but it was not working when we last tested it.
I played with the standard tweeter for some time, but finally decided to go for a Accuton CELL C30-6-358. You have to try to know what it does - right?
This caused of course crossover changes and to be honest it took quite some time to find the design I have today. I tried mainly lower crossover points but it all fell into place when I decided to go for a 6dB filter, with impedance and resonance compensation circuits. Moving the tweeter in line with mids did the final magic
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
Right now I'm in that phase "don't change anything" which normally lasts for a couple of months!
B&w 802N
Help help im restoring some good old nautilus 802 N
Whwn i bougth them all damping material inside middrange housing was gone ..
Can somone help me with some pics or som info .. how much damping material in grams and maybe how it placed around in the housing,,,,,,,
Thanks Andre Vestvoll
Help help im restoring some good old nautilus 802 N
Whwn i bougth them all damping material inside middrange housing was gone ..
Can somone help me with some pics or som info .. how much damping material in grams and maybe how it placed around in the housing,,,,,,,
Thanks Andre Vestvoll
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