Nothing is said about how these were measured? Just to look at the on-axis response can be highly misleading. We tend to listen to speakers in a room. Power response is a factor, so is spectrum, angle, delay and angle of first reflections.
Measured in room, on axis. THe waveguie offsets the tweeter so that acoustic alignment in near perfect. The Xover is set to where the speaker has constant directivity matching to the woofer at about 1.5K. THe XO is active LR24 so no major phase issues.
Perhaps we are going about this wrong. Why not show an example of a speaker driver that performs according to your standard. FYI, here is a wooer to consider.
www.audioexcite.com AudioTechnology 15H521206SDKM
It has an accordian surround, so no resonant notch to speak of.
www.audioexcite.com ScanSpeak 15W/4531G00
classic scan speak
www.audioexcite.com SB Acoustics SB15MFC30-4
here is the MCF from SB. ALso very usable
Perhaps we are going about this wrong. Why not show an example of a speaker driver that performs according to your standard. FYI, here is a wooer to consider.
www.audioexcite.com AudioTechnology 15H521206SDKM
It has an accordian surround, so no resonant notch to speak of.
www.audioexcite.com ScanSpeak 15W/4531G00
classic scan speak
www.audioexcite.com SB Acoustics SB15MFC30-4
here is the MCF from SB. ALso very usable
Unsmoothed 0 - 90I would think that for almost all drivers that would be unintelligible
OK I concede that I based this comment on my own attempts at doing 0 - 90 measurements. With a proper anechoic environment it should be ok. especially if the angles are picked well and not too many. For some reason I was imagining a plot with 90 individual measurements, which is obviously not the intent
Attached was my attempt on my MTM's... I don't remember what sort of smoothing was applied to this but as you can see it gets pretty useless at low frequencies, however it is the higher frequencies where we are generally interested anyway.
Tony.
Attachments
Here's my other Alpair 7.3 (0° and 10°) - looks basically the same:
Here's both drivers 0° (top) and 10° (bottom) - excellent tracking:
Attachments
Markus,
There are any number of people here that like that driver. Get over it. You are not going to change minds with an FR plot.
Now, do you really listen to wide-range drivers on axis? Of course not. Take the 0* trace off of the graph. Now does it sound better? And of course you have never cheated and used a bit of smiley-face EQ, have your?
Bob
There are any number of people here that like that driver. Get over it. You are not going to change minds with an FR plot.
Now, do you really listen to wide-range drivers on axis? Of course not. Take the 0* trace off of the graph. Now does it sound better? And of course you have never cheated and used a bit of smiley-face EQ, have your?
Bob
Why do I need to "get over it"? I've just presented the facts. People can like whatever they want. I don't tell them not to like the driver.
But all of that doesn't change the fact that
a) the data presented by the manufacturer is different from what I've measured and
b) the off axis data is not smooth.
If you want the frequency response to be smooth within the listening window then you have to listen to this driver at 0°. Of course it has to be equalized first.
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Markus when one talks about a manufactures curves being similar to self measurements, you don't expect everything to look the same. In the case of the MA curve vs yours, yes they are quite different, but both show the presence of the peaks and dips that would cause one concern over the driver. The scale makes a huge difference to ones perception of how good something appears.
Some manufactures are quite honest with their measurements. SEAS happen to be one of them and in this case, when one says a comment like this, they are not saying it meaning that what SEAS measure will exactly match what you measure. What's being said is that SEAS are honest enough to post their measurements displaying what their drivers do warts included, and it's these warts that are the important bit.
In other words does the manufacture try and hide the fact that their driver has a glaring resonance issue at X frequency of X decibels? SEAS certainly do not and as such people are not surprised when they measure their magnsium cone excel and see mount everst in the top end. Now providing a driver doesn't show any other gross abnormalities, when under self measurement, then I think the manufacturer was honest in their measurements. If there are small deviations +-1.5dB for example then I simply ignore them as it is the overall trends that tend to matter most.
Some manufactures are quite honest with their measurements. SEAS happen to be one of them and in this case, when one says a comment like this, they are not saying it meaning that what SEAS measure will exactly match what you measure. What's being said is that SEAS are honest enough to post their measurements displaying what their drivers do warts included, and it's these warts that are the important bit.
In other words does the manufacture try and hide the fact that their driver has a glaring resonance issue at X frequency of X decibels? SEAS certainly do not and as such people are not surprised when they measure their magnsium cone excel and see mount everst in the top end. Now providing a driver doesn't show any other gross abnormalities, when under self measurement, then I think the manufacturer was honest in their measurements. If there are small deviations +-1.5dB for example then I simply ignore them as it is the overall trends that tend to matter most.
^
I wouldn't mind if measurements would deviate only by a small amount but they don't. The way the Alpair data is presented is misleading and certainly not what I've measured.
Generally I think something is fundamentally wrong if the customer has to pay for a product up front just to find out if the product has certain features. You seem to be content with the status quo, I'm not.
I wouldn't mind if measurements would deviate only by a small amount but they don't. The way the Alpair data is presented is misleading and certainly not what I've measured.
Generally I think something is fundamentally wrong if the customer has to pay for a product up front just to find out if the product has certain features. You seem to be content with the status quo, I'm not.
What part of
Shows that they don't?
You've got dips and peaks at similar frequencies, with the general uneveness elsewhere, actually being superior in your measurements. So what if the magnitude of the peaks in MAs plots are slightly subdued, most likely due to a small amount of smoothing, that's life, smoothing happens.
I agree with you when you say this...
I am not happy, but there is not much one can do about it. You always take a risk when you buy a driver that hasn't been extensively measured by an impartial third party. This is why people tend to play it safe and buy drivers that have been measured. Yes in an ideal world all manufactures would measure in exactly the same way, with the same measurement conditions and would provide an extensive range of measurements that show exactly how linear their drivers are, but that's not the case.
Shows that they don't?
You've got dips and peaks at similar frequencies, with the general uneveness elsewhere, actually being superior in your measurements. So what if the magnitude of the peaks in MAs plots are slightly subdued, most likely due to a small amount of smoothing, that's life, smoothing happens.
I agree with you when you say this...
I am not happy, but there is not much one can do about it. You always take a risk when you buy a driver that hasn't been extensively measured by an impartial third party. This is why people tend to play it safe and buy drivers that have been measured. Yes in an ideal world all manufactures would measure in exactly the same way, with the same measurement conditions and would provide an extensive range of measurements that show exactly how linear their drivers are, but that's not the case.
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It seems t me that you could argue that the MA graph look sworse in many ways. You also have to ask about measurement enviroment as well measurement equipment. Try crossong it to a RAAL if you want a better top end. In this regard, it is a very attractive midrange. The cone resonance is common and can be seen in other top end drivers.
That's how large[r] wideband drive units work. Resonance is how HF is created and always has been, sometimes with the addition of other cones etc., sometimes not.
I have no particular 'interest' one way or the other in terms of the graphs presented here or elsewhere -they are what they are. To my simple little mind they appear to be showing more or less the same basic response trend: as has been noted above the real difference is that of the graph scales. The manufacturer plots show -10dB - 110dB (120dB dynamic range). The ones here are showing 40dB - 90dB (50dB dynamic range). Presenting relatively wide dynamic ranges is not particularly unusual for wideband driver manufacturers. Tang Band regularly use 100dB for example; Fostex have often used similar, but have reverted recently to about 70dB with ~ 1/3 octave smoothing. Mark Audio, AFAIK, do not apply software smoothing to their published data -it's raw anechoic, but the wide dynamic range provides some of that effect (ditto for TB, although I believe they use varying amounts of smoothing too depending on the driver in question). And so on. Which is fair enough -they wouldn't sell drivers if they didn't -if people saw genuine, uncompressed, unsmoothed data from almost any driver, but particularly the majority of widebanders, they'd run a mile. Despite being perfectly happy beforehand. QED -they're doing something right (in terms of general type).
To be sure, nothing is ever perfect; different test setups & conditions will always introduce a degree of variability. This is to be expected. What is slightly surprising to me is that
a/ this thread seems to have appeared from the dead after about 9 months, and
b/ data with dissimilar scales appears to be being used for comparisons, violating the first principals of scientific methodology, seemingly with the object of presenting said driver in a negative light.
Now, you can call me biased if you like. I happen to sell some speaker plans that use MA drivers. As does Bob. But I'd also ask people to recall that we're both perfectly capable of designing & selling speaker plans / speakers using drivers from other manufacturers also. Which, er, we also both happen to do, and means we're not especially beholden in any direction.
I have no particular 'interest' one way or the other in terms of the graphs presented here or elsewhere -they are what they are. To my simple little mind they appear to be showing more or less the same basic response trend: as has been noted above the real difference is that of the graph scales. The manufacturer plots show -10dB - 110dB (120dB dynamic range). The ones here are showing 40dB - 90dB (50dB dynamic range). Presenting relatively wide dynamic ranges is not particularly unusual for wideband driver manufacturers. Tang Band regularly use 100dB for example; Fostex have often used similar, but have reverted recently to about 70dB with ~ 1/3 octave smoothing. Mark Audio, AFAIK, do not apply software smoothing to their published data -it's raw anechoic, but the wide dynamic range provides some of that effect (ditto for TB, although I believe they use varying amounts of smoothing too depending on the driver in question). And so on. Which is fair enough -they wouldn't sell drivers if they didn't -if people saw genuine, uncompressed, unsmoothed data from almost any driver, but particularly the majority of widebanders, they'd run a mile. Despite being perfectly happy beforehand. QED -they're doing something right (in terms of general type).
To be sure, nothing is ever perfect; different test setups & conditions will always introduce a degree of variability. This is to be expected. What is slightly surprising to me is that
a/ this thread seems to have appeared from the dead after about 9 months, and
b/ data with dissimilar scales appears to be being used for comparisons, violating the first principals of scientific methodology, seemingly with the object of presenting said driver in a negative light.
Now, you can call me biased if you like. I happen to sell some speaker plans that use MA drivers. As does Bob. But I'd also ask people to recall that we're both perfectly capable of designing & selling speaker plans / speakers using drivers from other manufacturers also. Which, er, we also both happen to do, and means we're not especially beholden in any direction.
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Mark publishes raw data taken in an anechoic chamber on an IEC baffle with Linear-X using a professional quality measuring mic (good to 30k in the same sense that the ECM is good to 10k)
dave
Yes, SDX7 sealed. I also have an MTM trapezoid box designed. I have enuff SDX7 to build it, but may well (ie really should) adjust for available woofers. Initial sims suggest the new CSS 7" could be a viable candidate (vented)
dave
Yeah, the wide curved baffle is rather a "statement", and shares one characteristic with most OBs and large planar dipoles I've heard - need a lot of unimpeded floorspace to fully blossom - so WAF wouldn't be high for most folks. Sue's first comment was, those are pretty, who are they for?
There are certainly more compact footprint TMM or MTM arrangements that would work well with the A7.3. For a floorstander I'd be inclined towards the former to keep the Alpair around 36" height as in the Ellipses.
There are certainly more compact footprint TMM or MTM arrangements that would work well with the A7.3. For a floorstander I'd be inclined towards the former to keep the Alpair around 36" height as in the Ellipses.
Now those are nice!!!
Very similar baffle to what mine will have, albiet larger @ 23"w x ~52"h x ~<10"d.
Wife gave me a look the otherday I'll never forget when placing the test sub up on stilts making it 68" tall
Certainly gets your attention qhen walking in the door, this aint yo moma's speakers
Very similar baffle to what mine will have, albiet larger @ 23"w x ~52"h x ~<10"d.
Wife gave me a look the otherday I'll never forget when placing the test sub up on stilts making it 68" tall
Certainly gets your attention qhen walking in the door, this aint yo moma's speakers
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