Subscribed. I'm dabbling in the "easy to assemble" horn section 
xrk971 is an inspiration, and my builds (I prefer to call them "perpetrations") are even laxer in standards: minimize cost of raw materials (salvaged advertising signs), some modeling in hornresp. I do have DSP. I made a trial "Synergy" horn and can hear what all the hoopla is about Recently, and perhaps more relevant to this thread, I recently bought a high quality (or "price" at least ) BMS 8" coax. It is a "point source" and highly engineered, etc. In a not-quite-sealed-box, a pair sounds wonderful. Probably not a true quasi point source like Danley's stuff, although he does use similar coaxes in some speakers. I will have to try one in a horn/waveguide.
I watch with interest!
xrk971 is an inspiration, and my builds (I prefer to call them "perpetrations") are even laxer in standards: minimize cost of raw materials (salvaged advertising signs), some modeling in hornresp. I do have DSP. I made a trial "Synergy" horn and can hear what all the hoopla is about Recently, and perhaps more relevant to this thread, I recently bought a high quality (or "price" at least ) BMS 8" coax. It is a "point source" and highly engineered, etc. In a not-quite-sealed-box, a pair sounds wonderful. Probably not a true quasi point source like Danley's stuff, although he does use similar coaxes in some speakers. I will have to try one in a horn/waveguide. I watch with interest!
The best over-all mid range (from a comp driver) I have heard is EV DH-1506 drivers on the white whales (HR-9040), but then, even attempting as low as 500Hz was a bit of a stretch. With respect to "heavy-cone drivers" I would submit that a driver to be used in the application for mid-bass, would not be suitable for mid range, so I can see where you are coming from. Fortunately for me, I have a pair of the now-no-longer-available Audax PR-170zo, which carry a BL factor of 10 to drive a 6.2 gram aerogel cone. It's the MOST ideal cone type of driver to be horn loaded. I just wish there was something currently available for Mr. Lewinski to use in his system.
Attachments
Indeed. The cones in my short-list, though, have an Mms/Bl ratio of 0.71-0.76 vs. 0.6 for the PR170zo you describe. Higher, but not very high compared to other midranges in this size.
What's the Le of the PR170zo? I've come to believe a low Le is important and there I see a wider spread of values.
Examples:
605Nd: Le: 0.5mH; Mms/Bl: 0.76
M5N12: 0.15mH; 0.73
M5N8: 0.22mH; 0.71
6PEV13: 0.6mH; 0.73
6ND410: 0.67mH; 0.71
B&W FST: 0.18mH; 1.45. This one is not in my short list, but my current speaker, hence my reference. A very good midrange driver. Very low Le.
The M5N12 looks pretty good I think, plus listening reports support it.
I'm now turning towards the horn, and likely will revisit the driver short list when I have a horn short-list.
What's the Le of the PR170zo?
What's the Le of the PR170zo? Listed as .73mH
I've come to believe a low Le is important and there I see a wider spread of values.
I can't really say if "very low" Le is somehow better (?) for a mid range. I am only used to checking the Le of a woofer to see how high in frequency it might be responsive to, in relation to a chosen crossover point. As in, separating a "woofer" from a "sub-woofer" driver.
For what it's worth, I really like the M5N12 as well
What's the Le of the PR170zo? Listed as .73mH
I've come to believe a low Le is important and there I see a wider spread of values.
I can't really say if "very low" Le is somehow better (?) for a mid range. I am only used to checking the Le of a woofer to see how high in frequency it might be responsive to, in relation to a chosen crossover point. As in, separating a "woofer" from a "sub-woofer" driver.
For what it's worth, I really like the M5N12 as well
How does aerogel sound when compared against paper? I bet it sounds rather fluffy.
How low are you using the Audax drivers and in what range? Size of horn?
I have it on very reliable authority, the Aerogel cones sound like electrostatics on steroids
My mission is to push it down to 250Hz, through use of a 180Hz tractrix.
It will be rather large. Yet to be built. Pictures and a report forth coming.
Please stand by.
I have it on very reliable authority, the Aerogel cones sound like electrostatics on steroids
My mission is to push it down to 250Hz, through use of a 180Hz tractrix.
It will be rather large. Yet to be built. Pictures and a report forth coming.
Please stand by.
Maybe it will do that but the 170MO is good 400-1200 in a 180hz tractrix horn. What you don't want to do is "push" a driver down in a horn. YMMV
I used SABA greencone also. Great little drivers, but... not as good as compression drivers. The Avantgarde Duo sounds great, if that is what you are trying to make. But many don't like the 350Hz crossover point. I was comparing it to the ATC SCM100 and the ATC won in the midrange. Not at treble, although in retrospect, none of them has a very good tweeter. However, the DUO was very fun to listen to.
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Just one in a series of MANY missions (cone mid v1.0)
Yes, Gentlemen, I agree it's a bit of a "push". I have been wanting to use these drivers for a very long time now. I even had plans to mate them with a "helper"
low-mid driver.
This choice all revolves around at least 2 things: 1)The active crossovers I like best, have a choice of 250 or 500Hz points. 2) My ppsl mid-bass units are indeed superb, but sound their very best crossed no higher than 250Hz.
In my opinion, 250 hz is the very start of the "critical" voice range, and I have had really good results keeping it intact. Does this mean it's the "only way" ?
No, certainly not, but I am building upon what I have established that works well in my room, with my system.
Another approach I have (on the back burner) is to replace the ppsl units
with a true mid-bass cone driven horn, and once again use the white whales but this time at somewhere between a 600 or 700Hz crossover. This also entails changing the sub woofer configuration and raising the x-over point up from 60, to somewhere close to, but no higher than 100.
I apologize for high-jacking the thread, but tried to keep it on topic.
Yes, Gentlemen, I agree it's a bit of a "push". I have been wanting to use these drivers for a very long time now. I even had plans to mate them with a "helper"
low-mid driver.
This choice all revolves around at least 2 things: 1)The active crossovers I like best, have a choice of 250 or 500Hz points. 2) My ppsl mid-bass units are indeed superb, but sound their very best crossed no higher than 250Hz.
In my opinion, 250 hz is the very start of the "critical" voice range, and I have had really good results keeping it intact. Does this mean it's the "only way" ?
No, certainly not, but I am building upon what I have established that works well in my room, with my system.
Another approach I have (on the back burner) is to replace the ppsl units
with a true mid-bass cone driven horn, and once again use the white whales but this time at somewhere between a 600 or 700Hz crossover. This also entails changing the sub woofer configuration and raising the x-over point up from 60, to somewhere close to, but no higher than 100.
I apologize for high-jacking the thread, but tried to keep it on topic.
Scott, I've dealt with that 250 to 500 crossover point with horns for years and have came to the conclusion that 100 Hz is the sweet spot with a mid size cone handed off to a large format compression driver some where between 600 to 1K - the voice range extends down to 100 and so do most instruments. You are on topic - the midrange is 160 to around 1.4 k - it's difficult to find a horn that will cover that range well
What's the Le of the PR170zo? Listed as .73mH
I've come to believe a low Le is important and there I see a wider spread of values.
I can't really say if "very low" Le is somehow better (?) for a mid range. I am only used to checking the Le of a woofer to see how high in frequency it might be responsive to, in relation to a chosen crossover point. As in, separating a "woofer" from a "sub-woofer" driver.
For what it's worth, I really like the M5N12 as well
Here's one source that helped shape this belief in Le being important.
http://www.adireaudio.com/Files/WooferSpeed.pdf
Hands on, real results - read the Bruce Edgar horn articles-
Hornloudspeaker Magazine: Midrange horns/the Edgar Midrange Horn
Couldn't agree more! Those have been some key readings for me. In fact the Edgar Midrange Tractrix is my baseline for this project as it was said to be good with a 5" (LE-5).
OK, I'm going to expose my inabilities....
Attached is a...well...attempt to simulate the M5N12 in the Edgar Midrange Tractrix. Obviously something's very wrong. But what is it? BTW, the huge rear chamber was an attempt to simulate no chamber. It might need to be larger.
Help!
Attachments
Adire sales pitch paper
I read this again last night. I have had this printed out for quite a few years now. I'm not sold. I think the essay is interesting in a few ways, but not totally valid. For illustration purposes, they add both mass and inductance AFTER the fact, and compare the differences between the two. For my understanding, this is quite a bit different than what is inherent in the driver in the first place.
Again, this paper is titled, "woofer speed". We are discussing cone mid range drivers here, suitable for horn loading. According to Edgar, we want a low-mass, large magnet, and relatively stiff suspension type of driver. The horn does most, if not all the work. Acoustic transformers, if you will. God Bless Paul Klipsch, too
I read this again last night. I have had this printed out for quite a few years now. I'm not sold. I think the essay is interesting in a few ways, but not totally valid. For illustration purposes, they add both mass and inductance AFTER the fact, and compare the differences between the two. For my understanding, this is quite a bit different than what is inherent in the driver in the first place.
Again, this paper is titled, "woofer speed". We are discussing cone mid range drivers here, suitable for horn loading. According to Edgar, we want a low-mass, large magnet, and relatively stiff suspension type of driver. The horn does most, if not all the work. Acoustic transformers, if you will. God Bless Paul Klipsch, too
...And this is what I don't understand ! Why wanting a stiff suspension (low Qm) if having a high BL (large magnet) ? Don't we want in a long horn a short voice coil with just one layer of wire on it for a better control on low Xmax ? We want controlled microdynamic here, no ?
So why stiff suspension ? Do we need more damping than a strong BL couldn't not controll on low exercusions ? To say it on a different way, does a high Qm is not better for the behavior on a light cone about dynamic response ?
If stiff suspension, why light Mms Cone ? I just can't understand the logic as far we have a strong BL and a short coil for horn loading medium ?
Look at the B&C PE21 8" : the QM is very high (around 4) so no stiff suspension.
WHat is the concept I don't understand about the Edgar Horn requirement ?
So why stiff suspension ? Do we need more damping than a strong BL couldn't not controll on low exercusions ? To say it on a different way, does a high Qm is not better for the behavior on a light cone about dynamic response ?
If stiff suspension, why light Mms Cone ? I just can't understand the logic as far we have a strong BL and a short coil for horn loading medium ?
Look at the B&C PE21 8" : the QM is very high (around 4) so no stiff suspension.
WHat is the concept I don't understand about the Edgar Horn requirement ?
I find Horn drivers with stiff electrical "qe" and high resonance work best in a horn - strong magnets - tight gaps - high resonance frequency - light coils and cones. The horn does the work and the driver is driving the throat air load first (dampening the driver) instead of a direct radiator driving the room air load.
Why Horns?
Why Horns?
I suppose the throat chamber looks larger than it needs to be, you could set it to zero?Obviously something's very wrong. But what is it?
edit: I would also either mask rear chamber resonances, or just set Lrc to some small value.
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I wouldn't say this driver feels as if it has a loose suspension, by and large, but Qms is directly proportional to fs.
Heh. I know a guy that knows Kolbrek here in Norway. Maybe he will like mine. I would probably like his!
Thank you!
The simulation below is the same as original, except Vtc=Atc=0, and rear chamber resonances were suppressed when processing.
Looks better. But not good yet. What next?
Thanks again!
