I was thinking about trying out a B&W FST midrange until I saw the prices from B&W parts. However they do list the N800 midrange for around $180 which is still expensive but closer to budget. Does anyone know the specs for this driver and whether it is similar to the 6.5" tested by Zaph? The woven kevlar, foam surround jobby with neo magnet is the one i'm after.
It's hard to say, if you read the white paper, B&W at some point changed to Neo after having used ferrite in the previous 800 models. The Neo motor allows them to use a thick top-plate and therefore an under-hung motor which they say helped to lower distortion even further. You can find this in the 800 development white paper.
If you want higher sensitivity dedicated mids, here's a few more suggestions that will perform pretty darn well IN MY opinion
BG Neo8
PHL 1120
AE TD6M
Infinity 10PR80BZQ-FM04-E
Seas CA15RLY
JBL C500G
But do keep an eye on the power response of your speakers. these drivers can often play pretty high so it's tempting to do so, but IMO not worth it.
BG Neo8
PHL 1120
AE TD6M
Infinity 10PR80BZQ-FM04-E
Seas CA15RLY
JBL C500G
But do keep an eye on the power response of your speakers. these drivers can often play pretty high so it's tempting to do so, but IMO not worth it.
I believe the FST beats these for dedicated mid service, at least on paper. Flat damped foam surround, phase plug, high Fs and high efficiency seems to be key. The phl 1120 is probably the best of this type available to DIYers but is getting a bit long in the tooth. Similar offerings from Beyma and B&C dont seem to be quite as good.
The Neo 8 is a different beast though, I would like to try it one day.
The Neo 8 is a different beast though, I would like to try it one day.
Well starting with a 6.5" ""dedicated mid"" is fundamentally flawed as it is. If you must, the PHL and AE beat it in the sensitivity department for 6.5" mids if you must. The other factors are a wash.
The 4" Infinity ($30) are better dedicated mids than the B&W... dynamic, sensitive, and small, with a very high, very controlled breakup. The JBL is a beast, i'd love to get my hands on one.
The Seas isn't as sensitive (it's a midwoofer not technically a dedicated mid) but when relieved of woofer duties it's got world class midrange, and again wider dispersion than the B&W. Probably the odd man out, but Worth mentioning anyways dollar for dollar, despite an Excel Nextel probably being a better option.
The Neo 8 wants to be crossed a bit higher than most dedicated mids at the bottom of its passband (optimal for a TMWWW or maybe even a 4-way) but is as resolving as it gets with dispersion to spare. It'll run circles around the B&W.
Infinity also has(had?) a really world class rectangular mid driver which it used as a mid/woofer in its Cascade series of speakers, but it appears to be NLA (or at least no longer listed on their website). The thing had very low power compression when crossed around 300hz, had the horizontal dispersion of a 3" driver, and the breakup was up near 12khz.
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What impresses me most about the FST mid is its ability to sound clean and composed at high SPL. I figure the the 6.5" diameter helps with this compared to a smaller mid.
I have only listened to the Neo3 and found it sounds a bit dynamically constrained to my ears. I felt that something was missing (distortion?) I do wonder how the larger neo 8 compares
The inifinity 4" sounds interesting but doesnt seem to be available any longer?
I have only listened to the Neo3 and found it sounds a bit dynamically constrained to my ears. I felt that something was missing (distortion?) I do wonder how the larger neo 8 compares
The inifinity 4" sounds interesting but doesnt seem to be available any longer?
The off-axis response of this driver takes a "header" much past 1.8kHz.
To get a uniform polar response will generally require a low crossover freq. for the tweeter. B&W doesn't manage this in their own designs - so you tend to get a "dip" from 2-4kHz from them.
Don't forget the paper offerings from B&C and Beyma as well - both with flat-damped surrounds.
To get a uniform polar response will generally require a low crossover freq. for the tweeter. B&W doesn't manage this in their own designs - so you tend to get a "dip" from 2-4kHz from them.
Don't forget the paper offerings from B&C and Beyma as well - both with flat-damped surrounds.
I could use a waveguide loaded tweeter at around 2khz but yes the midrange is no longer covering the entire midband like a smaller diam driver could.
I have also considered the Audax 4" aerogel mid which would have good dispersion to around 3k however im a little concerned about power compression from such a small driver. I doubt it will have the same dynamics and effortless midrange as the FST at high SPL even if crossed over 500hz high pass.
The Beyma gets beaten by the FST in distortion measurements. I dont know about the B&C however I have read somewhere that "cheap" paper is used in the cone. The impedance plot does look quite rough.
My heart isn't set on the FST, just that it sounds and measures excellent. And looks nice too
I have also considered the Audax 4" aerogel mid which would have good dispersion to around 3k however im a little concerned about power compression from such a small driver. I doubt it will have the same dynamics and effortless midrange as the FST at high SPL even if crossed over 500hz high pass.
The Beyma gets beaten by the FST in distortion measurements. I dont know about the B&C however I have read somewhere that "cheap" paper is used in the cone. The impedance plot does look quite rough.
My heart isn't set on the FST, just that it sounds and measures excellent. And looks nice too
I could use a waveguide loaded tweeter at around 2khz but yes the midrange is no longer covering the entire midband like a smaller diam driver could.
I have also considered the Audax 4" aerogel mid which would have good dispersion to around 3k however im a little concerned about power compression from such a small driver. I doubt it will have the same dynamics and effortless midrange as the FST at high SPL even if crossed over 500hz high pass.
The Beyma gets beaten by the FST in distortion measurements. I dont know about the B&C however I have read somewhere that "cheap" paper is used in the cone. The impedance plot does look quite rough.
My heart isn't set on the FST, just that it sounds and measures excellent. And looks nice too
You can always do sims of the 4" driver to determine power-ratings in use. HOWEVER I'm almost certain that THD of the Audax driver isn't nearly as good DESPITE power input - if that really matters to you. (..and looking at the distortion profile of the B&W, most drivers will have a difficult time getting anywhere close by comparison.)
On the other hand I can guarantee you that the Audax will be more subjectively detailed (provided that it's loaded properly). On the other hand (and also because of it's low mms), it won't be as subjectively dynamic either (without regard to real dynamics). (..again, this is a function of the mass of the driver.) Still, you can match it to a lower midrange that has more mass to meet or exceed that of the B&W.
Even with a waveguide it will be difficult to get a good "match" with the B&W. (..it's the "abrupt" loss off-axis that contributes to this.)
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the 4" Mid is. The higher end CMMD flat mid in the cascade is not.
Look up the Primus P363 (current speaker). That is the midrange used in that. Yes, in a well designed DIY build you can take the mid from a $200 speaker and get a reference class 3-way.
I've got the Neo FST used with a 6" wave-guide crossed at 2.5khz 2nd order and this shows no dips as you go off axis so it can be done quite easily.
Subjectively this combo provides the most detailed and revealing sound that I've ever listened to and I do have experience with the Aerogels/SEAS Excel mag cones. It indeed goes very loud effortlessly too.
Subjectively this combo provides the most detailed and revealing sound that I've ever listened to and I do have experience with the Aerogels/SEAS Excel mag cones. It indeed goes very loud effortlessly too.
The throat diameter matches well with the faceplate profile of the HDS, it also matches well with any of the D2905 series too. A vifa XT25 is a perfect fit to the throat and also produces a very nice set of curves.
The only issue is mounting the tweeters to the wave-guide, to do this I made a ring out of 3mm thick aluminium. The ring has 3mm holes tapped into it on an inner circle which are used to hold the tweeter in place via the tweeters normal faceplate screw holes. There are then 4 holes drilled on an outer circle that line up with the tapped inserts monocor provide on the wave-guide that holds the ring + tweeter to the wave-guide.
The only issue is mounting the tweeters to the wave-guide, to do this I made a ring out of 3mm thick aluminium. The ring has 3mm holes tapped into it on an inner circle which are used to hold the tweeter in place via the tweeters normal faceplate screw holes. There are then 4 holes drilled on an outer circle that line up with the tapped inserts monocor provide on the wave-guide that holds the ring + tweeter to the wave-guide.
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