Suitable midrange cone, for bandpass mid in Unity horn.

[dwk123]

Puggie has a couple threads going on the same basic topic, so I'll cross post my previous cross post. DJK over on AA dug this guy up. No previoius exposure/experience, but the numbers look perfect, or at least better than anything I've seen previously if they're being honest. Looks like loudspeakersplus.com is the distributer in NA, although they aren't listed on the site.

http://www.paacoustic.com/Product_D...oductID=WN-520N

The summary:
5.5" nominal frame
1.5" CCA coil
0.14mH
80W
173hz Fs
0.200 Qts
1.23L Vas
2mm overhang
cloth edge
paper cone
carbonfiber/kevlar dustcap
smooth on-axis to 4Khz

[omarmipi]

Thanks for the explaination. I just modeled my first 4th order bandpass enclosure in WINISD and I now understand that covering 5 octaves is pretty much impossible. I wanted to use my Aura monopole combined with the unity waveguide as the mid. Is it difficult to get a 2,000Hz+ low-pass with the unity? When I construct the waveguide, would I only need one throat from the (2-3) midrange ports (the throat where you have the BMS compression driver)?

Why do you take the FS of the driver instead of the FS of the enclosure? Trying to get a flat response with a bandpass enclosure is a daunting task. I know you are using passive crossovers but would I be fine using an active crossover with 7 adjustable points of eqing?

[Patrick Bateman]

Doug,

Nice catch!

I just got off the phone with Loudspeakers Plus. I'm going to find out what quantity is needed to get these over here stateside. If I have to buy 20 or 50 and sell the rest, I'll do it.

I'll let everyone know how soon we can get it.

As I see it, the problem with the Unity midrange is that it's hard to find a small woofer with a huuuuge motor. I'm kind of a noob when it comes to motor design; but I think this is inherent to small woofers. Basically, if you put a big ferrite motor on tiny driver, the flux isn't concentrated into the gap. Of course it's not such a problem with large woofers, because the gap is much larger.

This could explain why the JBL GTI400, the Aurasound Whisper, and the P-Audio Winner are good candidates; they're all neo.

:: PB ::

[Patrick Bateman]

Originally posted by omarmipi
Thanks for the explaination. I just modeled my first 4th order bandpass enclosure in WINISD and I now understand that covering 5 octaves is pretty much impossible. I wanted to use my Aura monopole combined with the unity waveguide as the mid. Is it difficult to get a 2,000Hz+ low-pass with the unity? When I construct the waveguide, would I only need one throat from the (2-3) midrange ports (the throat where you have the BMS compression driver)?

Why do you take the FS of the driver instead of the FS of the enclosure? Trying to get a flat response with a bandpass enclosure is a daunting task. I know you are using passive crossovers but would I be fine using an active crossover with 7 adjustable points of eqing?

What is your "aura monopole?" Do you mean to say that you're using an Aurasound woofer at the apex of the horn or waveguide?

:: PB ::

[moray james]

Originally posted by Patrick Bateman
Doug,

Nice catch!

I just got off the phone with Loudspeakers Plus. I'm going to find out what quantity is needed to get these over here stateside. If I have to buy 20 or 50 and sell the rest, I'll do it.

I'll let everyone know how soon we can get it.

As I see it, the problem with the Unity midrange is that it's hard to find a small woofer with a huuuuge motor. I'm kind of a noob when it comes to motor design; but I think this is inherent to small woofers. Basically, if you put a big ferrite motor on tiny driver, the flux isn't concentrated into the gap. Of course it's not such a problem with large woofers, because the gap is much larger.

This could explain why the JBL GTI400, the Aurasound Whisper, and the P-Audio Winner are good candidates; they're all neo.

:: PB ::

I think that you may be jumping to some wrong conclusions. Rather I believe that the problem lies in the specific application of the driver required to do this type of job. This is a very odd application and there is practly no demand for a driver with these caracteristics so few are made. I really think that is the simple answer.
To say that big ceramic magnets on a small driver cannot be made to keep the flux concentrated in the gap is fiction the motot structure and magnet is not to blame. Flux is flux no matter if the source is a ceramic or a neo magnet. How much flux from the magnet that you can concenrate into the gap is dependant upon the size of the top plate and the geometry of the motor structure. Once you saturate the top plate and or the pole piece then you have hit you max flux. The answer is more and better quality iron for you motor parts. I think it is just that simple. Regards Moray James.

[omarmipi]

Originally posted by Patrick Bateman

What is your "aura monopole?"
:: PB ::

No it is a transducer that Aurasound use to make. I believe they bought the technology from Raido Shack as it is similar to the linaeum dipoles that they had in the LX-5 and some other loudspeakers.

Here is the pdf:
http://www.aurasound.com/pdf/ntl25-354-4a.pdf

So are drivers with large motors good, bad, or indifferent for this application. I am still confussed as to what specs the midrange enclosures are suppose to have.

Awesome! I got a value of 491Hz with the Audax HM100C0 drivers that I am currently using. I am not sure if the 54Hz Fs matters though. The motor on this thing is freakishly large too.

I just modeled it in WINISD and it has a super flat response compaired to the Vifa that I just modeled.
Vf = 0.6L, Vr = 0.6L, Tuning Freq. = 183.67Hz.

[omarmipi]

Sorry for the slow learning curve... I guess my Audax midrange drivers are only covering 1 octave because of the low FS.

[Patrick Bateman]

Originally posted by moray james
To say that big ceramic magnets on a small driver cannot be made to keep the flux concentrated in the gap is fiction the motot structure and magnet is not to blame. Flux is flux no matter if the source is a ceramic or a neo magnet. How much flux from the magnet that you can concenrate into the gap is dependant upon the size of the top plate and the geometry of the motor structure. Once you saturate the top plate and or the pole piece then you have hit you max flux. The answer is more and better quality iron for you motor parts. I think it is just that simple. Regards Moray James.

Moray, we're looking for a small woofer with a ridiculously powerful motor. Wouldn't a neo motor be better?

Originally posted by moray james
[B] I think that you may be jumping to some wrong conclusions. Rather I believe that the problem lies in the specific application of the driver required to do this type of job. This is a very odd application and there is practly no demand for a driver with these caracteristics so few are made. I really think that is the simple answer.

Funny you say that. Once GM and Puggie clued me in to what parameters to look for, Unity midranges started falling out of the sky. I can literally name 5-10 now.

Do you know what 75% of them have in common? You guessed it, neo motors.

[moray james]

the advantage that a neo will have is strictly physical they are smaller for a given strength. If you have ever played with any of the small full range driver that Fostex make the magnet is only marginally smaller than the cutout for the driver. That simply means that if you wanted more flux with a ceramic you would have to start stacking magnet slugs. So yes neo magnets would be easier to work with and lighter. That does not mean that they are better in terms of the flux they provide. They simply present a way to shrink your physical magnet size as compared to ceramics. You would be surprised to see what kind of increases in flux density are possible with top quality ceramic slugs (there are a number of grades available) when combined wit computer designed geometries top quality iron and super tight tolerences in build/ Today neo magnets are available at better prices than ever before so yes they are worth taking advantage of. This will result in a more reliable driver as big motors on the back of tiny frames have a habbit of being easily knocked off due to the small area availabe to secure the magnet.
Ok so you have found a dozen candidates that's good and I look forward to seeing the list. This is still a tiny number in the grand sceme of things. This is not your normal run of the mill mid driver. As you can see I have not disagreed that neo is nice for all the stated reasons I only wanted to point out that they do not make any better flux than would a ceramic magnet. No magic. Regards Moray James.

[Puggie]

Originally posted by Patrick Bateman
Doug,

Nice catch!

I just got off the phone with Loudspeakers Plus. I'm going to find out what quantity is needed to get these over here stateside. If I have to buy 20 or 50 and sell the rest, I'll do it.

I'll let everyone know how soon we can get it.

As I see it, the problem with the Unity midrange is that it's hard to find a small woofer with a huuuuge motor. I'm kind of a noob when it comes to motor design; but I think this is inherent to small woofers. Basically, if you put a big ferrite motor on tiny driver, the flux isn't concentrated into the gap. Of course it's not such a problem with large woofers, because the gap is much larger.

This could explain why the JBL GTI400, the Aurasound Whisper, and the P-Audio Winner are good candidates; they're all neo.

:: PB ::

Get prices I'm interested! another option would be www.bandor.co.uk, if you want really tiny drivers I could source some neo magnets and have Doreen build us a run of Bandor 50s with neo motors, but just replace the ceramic with say N40 neo keeping the physical magnet dimentions the same (I think we would be looking at about £50sterling per driver).

I like GM's analogy on carsound, speakers are similar to cars, fast ones are generally expensive and I guess fast small ones as standard are quite rare!!