BrianGT said:
Ah, so there is more than one? I thought there was only the 4" driver. Sorry about that. I have been picking up tidbits about the driver(s) here and there, but never picked up on different sizes. Oh well, I guess I will know more in a week or two.
You know, their Koda mid goes up to 5 kHz flat at 50 degrees off axis, and it doesn't use the XBL^2 motor. My guess then is that the larger Extremis must have stronger low end than the Koda (which already has some amazing midbass). Of course the Koda is designed for the mobile environment while the Extremis is more for home audio.
Those guys just won't stop inventing! Do we know how much these drivers are going to cost?
I'm really curious how their distortion levels are in the midrange where it seems as if the BL is less of an issue[?] Also, how efficient are they?
I have experience with Adire woofers and they all have really good bass performance. If I recall correctly, this 6.5" driver has an Xmax of 13 mm, meaning one of them could produce as much clean bass as two of their old AV8 woofers (which I have). That's practically incomprehensible.
I'm really curious how their distortion levels are in the midrange where it seems as if the BL is less of an issue[?] Also, how efficient are they?
I have experience with Adire woofers and they all have really good bass performance. If I recall correctly, this 6.5" driver has an Xmax of 13 mm, meaning one of them could produce as much clean bass as two of their old AV8 woofers (which I have). That's practically incomprehensible.
any progress???
Anybody tried the 6.5" yet?
These puppies is what i've been looking for for ages(i think).
The mtm on the pics is like taken out of the back of my head!
(Provided the x-over is in the 5k-ish hz.)
For starters i think one extremis and a vifa xt-25. Then on to mtm when economy allows. They seem to be expensive in norway (ship from us) anybody know of european dealer that will ship to norway?
Anybody tried the 6.5" yet?
These puppies is what i've been looking for for ages(i think).
The mtm on the pics is like taken out of the back of my head!
(Provided the x-over is in the 5k-ish hz.)
For starters i think one extremis and a vifa xt-25. Then on to mtm when economy allows. They seem to be expensive in norway (ship from us) anybody know of european dealer that will ship to norway?
What's the best enclosure?
So, what's the best application for this thing? I saw mention of a horn, and I think BrianGT said "appropriate box"- so, what is it?
Just playing around in WinISD, it seemed like I was getting some very long port lengths for appropriate tuning. Is a passive radiator the best way to go?
Here's what I really want to ask!
Could this work in a dipole?
I was looking at the driver, saying "This would cover most of the vocals... go from 50hz to 5khz if we push it.. hmm". It seems to have many of the characteristics that Linkwitz was looking for in the midrange on the Orion.
It's got low moving mass and low inductance, so it's probably got low energy storage. It's got 15mm Xmax, so even though it's only 140 cm^2, it's got some displacement. The XBL^2 is often said (by Adire, at least) to have very low distortion, and this speaker seems to have a large copper shorting ring to improve that even more.
At first I was scared of the 86 db efficiency, but if we can assume that it's been lowered by that shorting ring, then it's that low for a good reason.
Here's what I propose to do:
Use this driver from 150hz to 3(ish)khz, dipole. Cross it over actively to a high excursion 12" below, and a decent tweeter above, and tri-amp the whole thing.
I think I'll use four LM4780s on sealed lead-acid batteries for the tweets and mids, and use my Hafler 500 for the dipole bass.
SO- does anyone want to tell me what I'm missing? This would be an expensive learning experience.
Joe
So, what's the best application for this thing? I saw mention of a horn, and I think BrianGT said "appropriate box"- so, what is it?
Just playing around in WinISD, it seemed like I was getting some very long port lengths for appropriate tuning. Is a passive radiator the best way to go?
Here's what I really want to ask!
Could this work in a dipole?
I was looking at the driver, saying "This would cover most of the vocals... go from 50hz to 5khz if we push it.. hmm". It seems to have many of the characteristics that Linkwitz was looking for in the midrange on the Orion.
It's got low moving mass and low inductance, so it's probably got low energy storage. It's got 15mm Xmax, so even though it's only 140 cm^2, it's got some displacement. The XBL^2 is often said (by Adire, at least) to have very low distortion, and this speaker seems to have a large copper shorting ring to improve that even more.
At first I was scared of the 86 db efficiency, but if we can assume that it's been lowered by that shorting ring, then it's that low for a good reason.
Here's what I propose to do:
Use this driver from 150hz to 3(ish)khz, dipole. Cross it over actively to a high excursion 12" below, and a decent tweeter above, and tri-amp the whole thing.
I think I'll use four LM4780s on sealed lead-acid batteries for the tweets and mids, and use my Hafler 500 for the dipole bass.
SO- does anyone want to tell me what I'm missing? This would be an expensive learning experience.
Joe
Reality check - Doppler distortion
IM (Doppler) distortion % = 0.91 * (max 1-way excursion in mm) * (highest freq played in kilohertz)
Sooooooo, cross at 5kHz and use 10mm excursion with bass notes, your IM distortion will be 45%. The distortion sidebands created above and below the 5kHz tone will only be down about -6dB.
http://www.linkwitzlab.com/frontiers.htm#J
http://www.linkwitzlab.com/images/graphics/doppler1.gif
IM (Doppler) distortion % = 0.91 * (max 1-way excursion in mm) * (highest freq played in kilohertz)
Sooooooo, cross at 5kHz and use 10mm excursion with bass notes, your IM distortion will be 45%. The distortion sidebands created above and below the 5kHz tone will only be down about -6dB.
http://www.linkwitzlab.com/frontiers.htm#J
http://www.linkwitzlab.com/images/graphics/doppler1.gif
Re: Reality check - Doppler distortion
Thanks for the quick reply!
However, I must say- this sounds like a condemnation of the driver for ANY use that uses much of the Xmax...
If you are you saying that it would be better to use it in a box that controls excursion as it approaches resonance, then is all of this Xmax even good for anything?
I will definitely read more about Doppler distortion after I get off work today. Any other links are appreciated.
Thanks for the quick reply!
However, I must say- this sounds like a condemnation of the driver for ANY use that uses much of the Xmax...
If you are you saying that it would be better to use it in a box that controls excursion as it approaches resonance, then is all of this Xmax even good for anything?
I will definitely read more about Doppler distortion after I get off work today. Any other links are appreciated.
catapult said:
small monitor?
Ok, I've been thinking about this- we agree that it can play Loud, Clean, Low, and/or High- but only three of those. How about putting the Extremis 6" into a 0.5 cu ft vented box tuned to somewhere around 30 hz? You could power it with a digital amp, and use another (smaller) chip amp to power a sealed-back mid and tweeter.
Here's what I'm thinking:
Active crossovers to run the extremis from 40hz to 500hz (doppler seems OK there, even better if VB helps control excursion), then an Eminence LA6 line array driver from 500hz to 3khz, crossed over to a (yet unidentified) tweeter. It looks like you could get at least 105db @ 1m out of this setup, fairly cleanly from 40 hz on up. That's not so impressive- but with the sealed back mid the whole thing could be an 9x10x11" box.
Now, one of the things I'm counting on is the LA6's gobs of headroom so that a few active filters can flatten its FR between 500 and 3k without distressing it. These two drivers seem to have a much flatter FR than say- the Koda 8 and the sealed-back Alpha 8. I did not consider cloth dome midranges, but I've never heard good things
So, how's it sound? The reality check on doppler distortion was great- anything else I'm missing would be another good learning experience!
Joe
Ok, I've been thinking about this- we agree that it can play Loud, Clean, Low, and/or High- but only three of those. How about putting the Extremis 6" into a 0.5 cu ft vented box tuned to somewhere around 30 hz? You could power it with a digital amp, and use another (smaller) chip amp to power a sealed-back mid and tweeter.
Here's what I'm thinking:
Active crossovers to run the extremis from 40hz to 500hz (doppler seems OK there, even better if VB helps control excursion), then an Eminence LA6 line array driver from 500hz to 3khz, crossed over to a (yet unidentified) tweeter. It looks like you could get at least 105db @ 1m out of this setup, fairly cleanly from 40 hz on up. That's not so impressive- but with the sealed back mid the whole thing could be an 9x10x11" box.
Now, one of the things I'm counting on is the LA6's gobs of headroom so that a few active filters can flatten its FR between 500 and 3k without distressing it. These two drivers seem to have a much flatter FR than say- the Koda 8 and the sealed-back Alpha 8. I did not consider cloth dome midranges, but I've never heard good things
So, how's it sound? The reality check on doppler distortion was great- anything else I'm missing would be another good learning experience!
Joe
What about a reference design here for the Extremis? It could be a community project here using parts that are affordable and available.
I'm thinking a simple two way monitor with a passive crossover, ported or sealed to keep construction simple.
Some suggestions for the tweeter are the Hi Vi TN28 (good price), Vifa XT25 of course, maybe some of the Seas tweeters? Something not too exotic, hard to find, or expensive.
This could be a great way for speaker design newbies like myself to learn about the design process and end up with very high quality speakers.
Anyone else think this is a good idea?
I'm thinking a simple two way monitor with a passive crossover, ported or sealed to keep construction simple.
Some suggestions for the tweeter are the Hi Vi TN28 (good price), Vifa XT25 of course, maybe some of the Seas tweeters? Something not too exotic, hard to find, or expensive.
This could be a great way for speaker design newbies like myself to learn about the design process and end up with very high quality speakers.
Anyone else think this is a good idea?
The response of this driver doesn't look particularly flat to me:
extremis driver description
It looks to me like it would need a notch filter around 1.5k
Now if there were some smoothing in that chart then it be hiding some breakup at this point.
I have some doubts about the value of so much xmax for a driver that handles midrange. Now if you cross it low and use it as a woofer, this is different, but then I'd rather an 8" driver which seems more fit for the task.
extremis driver description
It looks to me like it would need a notch filter around 1.5k
An externally hosted image should be here but it was not working when we last tested it.
Now if there were some smoothing in that chart then it be hiding some breakup at this point.
I have some doubts about the value of so much xmax for a driver that handles midrange. Now if you cross it low and use it as a woofer, this is different, but then I'd rather an 8" driver which seems more fit for the task.
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