Clearly you think I'm on a crusade here. That couldn't be further from the truth. I'm not going to follow this guy around and try to discredit him everywhere. I've been aware of that thread since it started. Thanks for the reminder though. He's still insisting MTX's claims are unconfirmed (even though he has no idea if they are or not) but still hasn't even measured his own driver.
When I see an interesting thread in the forums I participate in regularly I will join in the conversation like I did here. Like I said, if he didn't join the forum just to try to debate me about claims that clearly are not true this would have ended a long time ago.
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What a ridiculous statement. He explains HOW to read the graph and THEN points out the data specifically. He's done nothing against you or the company but point out the errors and ask questions.
Your replies are very unbecoming of a reputable company. If you can't help out then do yourself (and the company) a favour and stop digging holes.
Hi guys -- short introduction... I am also involved in the HT line from SI. Some of you may have heard of Sundown Audio on the car audio side of things... that is my "day job" so to speak. Figured I would drop in here as well to make a few comments as I am pretty excited about the 24" project.
I'm not going to try to address everything in the thread by any means... just make some comments and add some info.
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A few things worth noting :
1) The Klippel test was done with the exact same spider design as the SI-HT 24 ; simply a version with a few more layers for extra stiffness. The surround does vary, of course, but the original 15" driver tested has a very wide CMS curve using the same spider pack :
* Using the 50% standard (Rest CMS is 0.17) of 0.085 we don't even reach that within the boundary of the test. If you go for the stronger 75% standard it's still over 30mm one-way by CMS on the original test. The SI-HT 24" surround isn't quite as massive as the tested 15" -- but we can tell that our spider pack isn't going to be the limit based on the data we have. Not to say the SI-HT 24 surround is a slouch... it is one of the bigger half rolls out there so I do expect good results from it as well.
As Nick has said actual 24" data is forthcoming. It's a brand new project and we are pretty excited about it so any data that is available has been shared. Not sure about everyone else but I love seeing prototype data.
It's also pretty easy for folks to get heated about technicalities... especially if you are as passionate and excited about this stuff as we are. I'd like to propose that everyone just have a few beers
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2) Thermal limitation is not as much of an issue as some are concerned with; the motor and coil combination is very capable of handling well in excess of 1500 RMS ESPECIALLY in an HT environment. Both parts in concert have been used in other drivers that do so on a daily basis. They are "car audio tested" so to speak... those guys are pretty hard on their gear typically running 0.5 ohm (high current) and clipping their amps heavily on compressed "chopped and screwed" music to boot.
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3) The Le curve is decent as well as it sits ; the motor has a large Faraday ring in the magnet ID and also a pole cap ring :
* Klippel rates the X-Max by Le at ~20mm one-way. Now keep in mind this test is with the slightly shorter coil so the absolute Le figure is lower here than the static T/S from our first prototype (65mm vs. the 71mm used in the prototype).
We have discussed much more extensive Le treatments for HT applications as well. Based on what I've seen in this thread I think most of you will be very excited to see the results when we get them in.
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4) As far as the 35mm figure; that is a BL based figure only -- the majority of drivers on the market are rated by BL x-max as it is the most significant contributor to the THD.
There is plenty of data to go on for the increase up to the 35+ range with the changes in the motor and coil design (coil change to 71mm alone should net a 3mm gain from the original Klippel). We've done A-B Klippel before with the same type of changes and it has always played out nicely. This actual data will be forthcoming -- so stay tuned.
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In any event... best thing I can say is stay tuned and any concerns about having the EXACT data will be addressed -- not to mention performance enhancements will be made.
The only 24" to make it out to the public "as-is" was VERY well received by it's owner -- so we are pretty anxious to get some more feedback as this project develops.
I'm not going to try to address everything in the thread by any means... just make some comments and add some info.
-----
A few things worth noting :
1) The Klippel test was done with the exact same spider design as the SI-HT 24 ; simply a version with a few more layers for extra stiffness. The surround does vary, of course, but the original 15" driver tested has a very wide CMS curve using the same spider pack :
An externally hosted image should be here but it was not working when we last tested it.
* Using the 50% standard (Rest CMS is 0.17) of 0.085 we don't even reach that within the boundary of the test. If you go for the stronger 75% standard it's still over 30mm one-way by CMS on the original test. The SI-HT 24" surround isn't quite as massive as the tested 15" -- but we can tell that our spider pack isn't going to be the limit based on the data we have. Not to say the SI-HT 24 surround is a slouch... it is one of the bigger half rolls out there so I do expect good results from it as well.
As Nick has said actual 24" data is forthcoming. It's a brand new project and we are pretty excited about it so any data that is available has been shared. Not sure about everyone else but I love seeing prototype data.
It's also pretty easy for folks to get heated about technicalities... especially if you are as passionate and excited about this stuff as we are. I'd like to propose that everyone just have a few beers
-----
2) Thermal limitation is not as much of an issue as some are concerned with; the motor and coil combination is very capable of handling well in excess of 1500 RMS ESPECIALLY in an HT environment. Both parts in concert have been used in other drivers that do so on a daily basis. They are "car audio tested" so to speak... those guys are pretty hard on their gear typically running 0.5 ohm (high current) and clipping their amps heavily on compressed "chopped and screwed" music to boot.
-----
3) The Le curve is decent as well as it sits ; the motor has a large Faraday ring in the magnet ID and also a pole cap ring :
An externally hosted image should be here but it was not working when we last tested it.
* Klippel rates the X-Max by Le at ~20mm one-way. Now keep in mind this test is with the slightly shorter coil so the absolute Le figure is lower here than the static T/S from our first prototype (65mm vs. the 71mm used in the prototype).
We have discussed much more extensive Le treatments for HT applications as well. Based on what I've seen in this thread I think most of you will be very excited to see the results when we get them in.
-----
4) As far as the 35mm figure; that is a BL based figure only -- the majority of drivers on the market are rated by BL x-max as it is the most significant contributor to the THD.
There is plenty of data to go on for the increase up to the 35+ range with the changes in the motor and coil design (coil change to 71mm alone should net a 3mm gain from the original Klippel). We've done A-B Klippel before with the same type of changes and it has always played out nicely. This actual data will be forthcoming -- so stay tuned.
-----
In any event... best thing I can say is stay tuned and any concerns about having the EXACT data will be addressed -- not to mention performance enhancements will be made.
The only 24" to make it out to the public "as-is" was VERY well received by it's owner -- so we are pretty anxious to get some more feedback as this project develops.
As Nick has said actual 24" data is forthcoming. It's a brand new project and we are pretty excited about it so any data that is available has been shared. Not sure about everyone else but I love seeing prototype data.
It's also pretty easy for folks to get heated about technicalities... especially if you are as passionate and excited about this stuff as we are. I'd like to propose that everyone just have a few beers
I love to see data too, prototype or not. The issue here is that the prototype data is being extrapolated upon and then being presented as end product data and claims are being made that are not true. I know that's not your fault but it's the reason this discussion has gone in this direction.
Anyway, Nick said he can't find anyone to test a 24 inch driver, which is actually the opposite of saying the data is forthcoming.
20 mm xmax is nothing to be ashamed of, it's impressive, especially for a driver this large.
But this means that by your own admission this driver has 20 mm xmax as measured by Klippel and interpreted by Klippel standards, not 36 as claimed.
Bl is the most significant limit to xmax, that's true. But several other factors limit xmax too and it's disingenuous to ignore the other factors. If your driver was tested by an independent 3rd party these other factors would certainly not be ignored, xmax would be stated as 20 mm in this case. I can link to plenty of 3rd party testing of other products if you like, and you can see that they ALWAYS show xmax as a product of the lowest performing factor, whether it's due to compliance variation, inductance variation, etc.
Here's a better paper to understand Klippel standards.
http://www.klippel.de/fileadmin/kli...plication_Notes/AN_05_Displacement_Limits.pdf
Since Bl is the most important factor I would have no problem with advertising the Bl limited xmax on the website as long as it is clearly stated that other factors limit xmax to 20 mm.
And obviously I'd like to see the "highest displacement driver on the planet" claim deleted. The fact that it's still there is deliberately fraudulent at this point.
That may very well be true but why not wait until you can measure and confirm this before presenting it on the website as fact? If SI fixed the website there would truly be nothing more to discuss until the real data is presented. At the very least these specs should clearly be marked as anticipated results, not end product measured parameters.
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Jacob, thanks for that generous and informative post. It's quite the opposite of the kind of bashing and whining that Nick has provided. Bravo and keep it up!
Sure we all want the specs to be accurate, & i expect we'll see them appear soon.
If the Xmax is only 20mm i think the main limitation will be the Power rating, but i wouldn't write it off.
2 sets of Power ratings ?
Even with 450W to each coil, it doesn't equate to 1500W ?
Effeciency could be improved with a bit more Gauss though
If the Xmax is only 20mm i think the main limitation will be the Power rating, but i wouldn't write it off.
2 sets of Power ratings ?
Even with 450W to each coil, it doesn't equate to 1500W ?
Effeciency could be improved with a bit more Gauss though
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