This is quite an insight on how SL test his drivers. Apparently he drives them to 30v vpp.
Triggered burst measurements of tweeters
There is an example of comparison between Seas 25TFFC and Neo3 and how they differ in such application.
I know some would argue that these are not audible, but surely if the objective is accuracy then the transducer needs to faithfully reproduce the input signals?
Then of course above all things the "wallet factor" 😀
Triggered burst measurements of tweeters
There is an example of comparison between Seas 25TFFC and Neo3 and how they differ in such application.
I know some would argue that these are not audible, but surely if the objective is accuracy then the transducer needs to faithfully reproduce the input signals?
Then of course above all things the "wallet factor" 😀
It would be interesting if SL would do the same measurements at a frequency the Neo3 actually can handle.... like 3 kHz. We who have used this driver knows its no good below 2.5 kHz or so. The power compression loss seen should be the same though.
30V p-p is A LOT for a tweeter, very tough test this is.
30V p-p is A LOT for a tweeter, very tough test this is.
Last edited:
I just refrained from posting the same thing. Here is my though: I don't place much credence on tests done w/o the intended crossover in place.
Apparently SL likes to cross tweeters very low. 1440 hz for Phoenix and Orion and 1khz for pluto.
"The large amount of distortion at relatively low power level would rule out this driver for my applications, which usually require a low crossover frequency."
GR-Research is quoting usable xo point of 2khz and 1khz for monopole or dipole repectively: http://gr-research.com/pdf/NEO3.pdf
Zaph mentioned about the ribbons/planar only usable 2.5khz and above: Zaph|Audio
"The large amount of distortion at relatively low power level would rule out this driver for my applications, which usually require a low crossover frequency."
GR-Research is quoting usable xo point of 2khz and 1khz for monopole or dipole repectively: http://gr-research.com/pdf/NEO3.pdf
Zaph mentioned about the ribbons/planar only usable 2.5khz and above: Zaph|Audio
His point was that he didn't want to test its distortion using the best crossover point for the driver, but at the crossover point that he requires for his application, hence the low frequency.
That's what he stated at the end of that section.
Edit: Just too late to point it out first. 🙂
That's what he stated at the end of that section.
Edit: Just too late to point it out first. 🙂
Yes, SL uses 1440 Hz because that is as far as he can push the 8" midwoofer. The problem with the low crossover is also that the tweeter is pretty omni there so w/o a rear tweeter the polar response really balloons off axis. A rear tweeter helps, but has other problems. A higher x-o point (as I use in the NaO) helps more. But I am taking a different tack on improving the polar response of dipoles at higher frequency. Here are some results I just took today. The polar plots are constructed form measurements taken at every 5 degrees. I repeat, these are measurement, not simulations. The crossover point is 1200 Hz. The frequency for the polar plot is noted at the top of each figure.
An externally hosted image should be here but it was not working when we last tested it.
The NAOs uses 2x 6.5" drivers, my assumption to reach certain target SPL? By doing this the baffle can be narrower (as supposed to 8") and hence the tweeter xo can be higher. At what frequency do you cross the tweeters in your design if I may ask?
Higher tweeter frequency is definitely desired as not everyone can afford $300 (times four) Millienium tweeters.
What is this "new approach" that you're working on re: tweeter polar response. 🙂
Higher tweeter frequency is definitely desired as not everyone can afford $300 (times four) Millienium tweeters.
What is this "new approach" that you're working on re: tweeter polar response. 🙂
Hmmm, all very interesting. Very interesting. I hope JohnK will share more.
I've been using the Neo3PDR crossed at 1700 LR4 acoustically. Personally, I like it a lot. I hear nothing I consider a problem yet. Of course, maybe I need more outside references...
To bad SL has already ruled it out - it seems like a decent driver to me. Maybe his test is a little harsh?
I've been using the Neo3PDR crossed at 1700 LR4 acoustically. Personally, I like it a lot. I hear nothing I consider a problem yet. Of course, maybe I need more outside references...
To bad SL has already ruled it out - it seems like a decent driver to me. Maybe his test is a little harsh?
Looks like an apples and oranges comparison.
http://www.seas.no/images/stories/vintage/pdfdataheet/h0519_25tffc.pdf
http://www.radiapro.net/uploads/NEO3WhitePaper.pdf
Wonder if Sig looks at the 20 Watt vs. 80 Watt input power and 3.5 vs. 6 ohm nominal impedance before comparing the Lincoln Town Car to a Greyhound bus. Maybe his philosophy goes something like: test first - read specifications later......😀
http://www.seas.no/images/stories/vintage/pdfdataheet/h0519_25tffc.pdf
http://www.radiapro.net/uploads/NEO3WhitePaper.pdf
Wonder if Sig looks at the 20 Watt vs. 80 Watt input power and 3.5 vs. 6 ohm nominal impedance before comparing the Lincoln Town Car to a Greyhound bus. Maybe his philosophy goes something like: test first - read specifications later......😀
Hey John, how are you doing that? I've been toying with a waveguide on my dipole baffle hoping to achieve a bit more directivity.
Current Project
Rats!
That throws a wrench in my plans. My hero has declared my tweeter unusable! I've been using the Neo3 as a dipole for some time (LR2 at 2000hz). I've been quite pleased with it.
My latest idea is to employ two of them in series to increase their impedance and sensitivity. I have recently ordered another pair and planned to do some extensive polar measurements. Am I wasting my time?
That throws a wrench in my plans. My hero has declared my tweeter unusable! I've been using the Neo3 as a dipole for some time (LR2 at 2000hz). I've been quite pleased with it.
My latest idea is to employ two of them in series to increase their impedance and sensitivity. I have recently ordered another pair and planned to do some extensive polar measurements. Am I wasting my time?
I think SL's point is more about the testing method, which looks pretty good, rather than the performance of specific tweeters. He doesn't say if he's testing with the back cup on or off but I suspect it's on unless he says otherwise. At 1.5K, the Neo3 is down 10dB with the cup on so you wouldn't expect it to perform very well down there. It's not really a fair test of what the driver can do but I suppose it's fair enough when you consider his low-crossover goals.
It is 30V p-p but shaped tone burst, which is only about 5W effective delivered to the driver ! That is very close to "real life" music signal situation. I wouldn't consider it very tough at all.
Crossing higher would make things better though, no doubt. How much better, is anyone's guess.
The NaO II is crossed at 2.2k Hz. The 2 6.5" mids provide the required SPL capability but there is a little more to it. A dipole response only has a directivity factor of 3 from about an octave below the dipole peak and lower. As the dipole peak is approached the directivity factor decreases. You can see how the pattern widens in this figure from my ABC Dipole Design Guide. d/w is dipole separation divided by wave length. The dipole peak is at d/w = 0.5.
The off axis response is actually higher in SPL than on axis just above the peak. I use the MTM format in the NaO in an attempt to take advantage of the M to M vertical cancellation in an effort to compensate for the change in horizontal directivity factor and keep the radiated power more constant. I don't claim to have it perfect but the reverberant field for the NaO is very smooth.
What I am doing now with the new design, I call it the NaO Note, I don't want to discuss just yet. Sorry. It is not an MTM though.
An externally hosted image should be here but it was not working when we last tested it.
The off axis response is actually higher in SPL than on axis just above the peak. I use the MTM format in the NaO in an attempt to take advantage of the M to M vertical cancellation in an effort to compensate for the change in horizontal directivity factor and keep the radiated power more constant. I don't claim to have it perfect but the reverberant field for the NaO is very smooth.
What I am doing now with the new design, I call it the NaO Note, I don't want to discuss just yet. Sorry. It is not an MTM though.
Thanks John. I visit your site quite often to learn about dipoles and to be honest I still cannot get around my head re: directivity factor. Especially your investigation about directivity in regards to half-space. My mental image of dipoles is a figure of 8, apparently not that simple!
I am very much interested in your new development of NaO Note ! 😎
I am very much interested in your new development of NaO Note ! 😎
Sure? I get 127 W if you apply a 30V p-p sine input to a BG Neo3. It's late, maybe I'm missing something totally obvious.....ha.....😕
My impression is that Stig is right on the mark - this is pretty much a torture test for a tweeter of average sensitivity. The SEAS unit he's comparing the NEO to is rated for 4 times the max input - not a very fair comparison unless you're into stacking the deck for whatever reason.....
The planar is supposed to be essentially resistive at 3.5 ohms so it makes calculating power with applied voltage a pretty simple affair.
This is quite shocking. I agree that the test-signal used probably isn't be much more difficult to reproduce than loud music. Considering I cross the Neo3W at 1.65 khz, I might be abusing it too much. I'll try to do some distortion measurements myself.
I'd like to know what the manufacturer thinks, but I can only find the following site: BG Radia - Home Theater Systems
EDIT: http://www.radiapro.net/
I'd like to know what the manufacturer thinks, but I can only find the following site: BG Radia - Home Theater Systems
EDIT: http://www.radiapro.net/
Last edited:
I believe that Bratislav is talking about RMS power over the whole burst - instantaneous peak power is indeed quite high, but doesn't mean much on that timescale.
- Status
- Not open for further replies.