Thinking of a cheap alternative to the AE TD12M, and the Faital 12PR300 looks promising. Neo magnet for cheap shipping, low Le, and high extension.
Any thoughts?
Any thoughts?
Defo said:
These are very different drivers. (..look at the the T/S param.s.)
Frankly I can't think of single driver quite like the TD12M.
On the other-hand there actually is a cheap alternative for the TD*15*M:
http://www.eminence.com/bassguitar_speaker_detail.asp?model=LEGENDCB15&speaker_size=15&SUB_CAT_ID=5
Re: Re: AE TD12M cheap alternative - Faital 12PR300?
While it may be possible to find a driver with similar T/S parameters, you're not going to find one "cheap" that is going to perform nearly the same. Look at the comparison with the Faital. It has no shorting rings and does not have a highly extended pole. This means high flux modulation and variance in Le with travel resulting in high distortion and vast changes in parameters with excursion.
It has a glass fiber VC former meaning all the inner heatsinking ability of the coil is removed. It has a 12.5mm long coil in an 8mm thick gap. Contrast that to our 25mm long coil in 18mm tall gap. The TD12M has literally about 5x the heatsinking area, and the entire inside of the coil is adjacent to the highly thermally conductive copper sleeve. This long gap and longer coil gives a much broader Bl curve. Even though it has this tiny short VC, the Faital still has 2x the inductance of the TD12M.
The dustcap will also have a resonance issue to deal with. This is one of the large reasons for the Lambda phase plug. The other is additional heatsinking. Finally look at the impedance curve. Even in a smoothed curve that is not at all properly scaled to tell you anything, you can see bumps at 500hz, 2Khz and 5500hz, indicating dustcap, cone, and or spider/surround resonances that haven't been properly damped.
Again, parameters are one thing. The 280hz spider resonance is a big issue. The 800hz dustcap resonance is a bigger issue. Then the 2KHz cone breakup is huge as well. Realistically you'd never want to use it past 500hz as an absolute maximum. Again, very short coil, short gap, non extended pole. It has a tiny fraction of the heat sinking ability of the TD15M. It still has nearly double the inductance with no shorting rings and will suffer from huge differences in Le with excursion and flux modulation issues.
If you're looking for something to be a drop in replacement in your box program, yes these options may model similarly. However if you're looking for an alternative to be used in a real speaker that actually exists, they won't even come close.
John
Defo said:
While it may be possible to find a driver with similar T/S parameters, you're not going to find one "cheap" that is going to perform nearly the same. Look at the comparison with the Faital. It has no shorting rings and does not have a highly extended pole. This means high flux modulation and variance in Le with travel resulting in high distortion and vast changes in parameters with excursion.
It has a glass fiber VC former meaning all the inner heatsinking ability of the coil is removed. It has a 12.5mm long coil in an 8mm thick gap. Contrast that to our 25mm long coil in 18mm tall gap. The TD12M has literally about 5x the heatsinking area, and the entire inside of the coil is adjacent to the highly thermally conductive copper sleeve. This long gap and longer coil gives a much broader Bl curve. Even though it has this tiny short VC, the Faital still has 2x the inductance of the TD12M.
The dustcap will also have a resonance issue to deal with. This is one of the large reasons for the Lambda phase plug. The other is additional heatsinking. Finally look at the impedance curve. Even in a smoothed curve that is not at all properly scaled to tell you anything, you can see bumps at 500hz, 2Khz and 5500hz, indicating dustcap, cone, and or spider/surround resonances that haven't been properly damped.
ScottG said:
Again, parameters are one thing. The 280hz spider resonance is a big issue. The 800hz dustcap resonance is a bigger issue. Then the 2KHz cone breakup is huge as well. Realistically you'd never want to use it past 500hz as an absolute maximum. Again, very short coil, short gap, non extended pole. It has a tiny fraction of the heat sinking ability of the TD15M. It still has nearly double the inductance with no shorting rings and will suffer from huge differences in Le with excursion and flux modulation issues.
If you're looking for something to be a drop in replacement in your box program, yes these options may model similarly. However if you're looking for an alternative to be used in a real speaker that actually exists, they won't even come close.
John
Re: Re: Re: AE TD12M cheap alternative - Faital 12PR300?
I believe I specified it as a: "cheap alternative". Greater limitations for its use? Absolutely. It is overall however and excellent substitute.
On the contrary for most domestic use applications it will in fact come close. Most people don't sink that much power into a such an eff. driver for long periods (in fact prob. p!ss little even with BSC), moreover most will not use a 15" driver above 500 Hz, or even 300 Hz. Its also unlikely that excursion will be an issue either for most applications.
So yes, it's an excellent substitute given reasonable domestic limitations and an average implementation.
On the other hand this doesn't detract from the excellence of the TD15M, which is IMO not only an excellent driver but also an excellent value.
So rather than getting your "feathers ruffled" and trying to "dis" a cheap alternative - try giving credit where it's due.
With some marketing savvy to such a response you'd understand (and "pitch") the driver's as *complementary*, NOT as a competitor.
Most people purchase at least 2 drivers. Those specifically looking for a cheap alternative probably can't muster the cash for 2 TD15M drivers (..and more likely not even close). But as a **"stand-by"** (provided it "fits" the design), they might be able afford the CB15. Further, it's not like they actually *want* the cheaper product, what they really want is your product - they just can't afford it at this time.
The APPROPRIATE response then is something like this:
(..std. greetings.)
I can understand the desire for the TD15M, it's not only a truly unique design capable of "x", "y", and "Z", but it's manufactured to much higher tolerances and with much better materials. It is a premium product, and unfortunately because of the premium design and manufacturing, the cost is at a modest premium.
Still, the driver is not only an excellent value when compared to its design and manufacturing expenses, it's also an excellent value when compared to other drivers priced at a premium. More traditional driver's like Focal, wholesale for more than twice the price of the TD15M while providing a measurably inferior product that is both considerably less efficient and less functional. Even "Pro" products like the best from JBL (often considered the standard in premium "pro" gear), are again less efficient and functional and are measurably inferior while still costing more.
If it's within your means, or perhaps "just out of reach", please seriously consider waiting until you can reasonably afford the purchase of a pair TD15M's. It really is that rare breed of product that's not only *more* than worth it's price - but even worth waiting for until it can be purchased.
If however you can't possibly afford a pair of TD15M's at (or anywhere near) this time, perhaps consider the Eminence CB15. While it is inferior in many respects, it *may* provide an acceptable compromise until you are able to purchase a pair of TD15M's. Note limitations "X", "Y", and "Z" for the Eminence driver. If you can work with these limitations then you will be able to latter replace the driver with the TD15M without any changes to the design, (which can result in a substantial savings). Of course if you want to try-out "x" or "y" with the TD15M's, then that option is then also available. You can even recoup some of your expenses with the lesser Eminence drivers by selling them on the after-market (perhaps Ebay or another service), thereby lowering your total cost and accelerating your purchase of the TD15M's. (..Tip: keep those Eminence boxes for re-sale purposes if you have to go this route.)
(..wrap-up "thank you for your interest" paragraph.)
badman said:
I believe I specified it as a: "cheap alternative". Greater limitations for its use? Absolutely. It is overall however and excellent substitute.
John_E_Janowitz said:
On the contrary for most domestic use applications it will in fact come close. Most people don't sink that much power into a such an eff. driver for long periods (in fact prob. p!ss little even with BSC), moreover most will not use a 15" driver above 500 Hz, or even 300 Hz. Its also unlikely that excursion will be an issue either for most applications.
So yes, it's an excellent substitute given reasonable domestic limitations and an average implementation.
On the other hand this doesn't detract from the excellence of the TD15M, which is IMO not only an excellent driver but also an excellent value.
So rather than getting your "feathers ruffled" and trying to "dis" a cheap alternative - try giving credit where it's due.
With some marketing savvy to such a response you'd understand (and "pitch") the driver's as *complementary*, NOT as a competitor.
Most people purchase at least 2 drivers. Those specifically looking for a cheap alternative probably can't muster the cash for 2 TD15M drivers (..and more likely not even close). But as a **"stand-by"** (provided it "fits" the design), they might be able afford the CB15. Further, it's not like they actually *want* the cheaper product, what they really want is your product - they just can't afford it at this time.
The APPROPRIATE response then is something like this:
(..std. greetings.)
I can understand the desire for the TD15M, it's not only a truly unique design capable of "x", "y", and "Z", but it's manufactured to much higher tolerances and with much better materials. It is a premium product, and unfortunately because of the premium design and manufacturing, the cost is at a modest premium.
Still, the driver is not only an excellent value when compared to its design and manufacturing expenses, it's also an excellent value when compared to other drivers priced at a premium. More traditional driver's like Focal, wholesale for more than twice the price of the TD15M while providing a measurably inferior product that is both considerably less efficient and less functional. Even "Pro" products like the best from JBL (often considered the standard in premium "pro" gear), are again less efficient and functional and are measurably inferior while still costing more.
If it's within your means, or perhaps "just out of reach", please seriously consider waiting until you can reasonably afford the purchase of a pair TD15M's. It really is that rare breed of product that's not only *more* than worth it's price - but even worth waiting for until it can be purchased.
If however you can't possibly afford a pair of TD15M's at (or anywhere near) this time, perhaps consider the Eminence CB15. While it is inferior in many respects, it *may* provide an acceptable compromise until you are able to purchase a pair of TD15M's. Note limitations "X", "Y", and "Z" for the Eminence driver. If you can work with these limitations then you will be able to latter replace the driver with the TD15M without any changes to the design, (which can result in a substantial savings). Of course if you want to try-out "x" or "y" with the TD15M's, then that option is then also available. You can even recoup some of your expenses with the lesser Eminence drivers by selling them on the after-market (perhaps Ebay or another service), thereby lowering your total cost and accelerating your purchase of the TD15M's. (..Tip: keep those Eminence boxes for re-sale purposes if you have to go this route.)
(..wrap-up "thank you for your interest" paragraph.)
I've used ScottG's suggestion before and it can be a good alternative to the TD15M at lower levels in limited bandwidth applications. There is however, none of the TD15M magic going on when even remotely pushed. Decent, inexpensive PA speakers, for those with limited money. Don't try to do the things that a TD15M will allow though. If you try to cross it over high enough for a typical 2 way, you will loathe yourself for your decision.
Disclaimer: I own several TD drivers
Those are good points but the TD series is for a specific niche and therefore if people do not want High SPL/low distortion, do not need to crossover a 12" driver at 1K to 2K then obviously there are many many other options. ACtually do not even think they need a 12" driver.
Now if someone wants to have high SPL/Low distortion and wants to build a 2-way and needs to crossover @ 1K -> 2K range then the TD12M has zero competition. Which is pretty cool, IMO and the price is only about $600 shipped for a pair. Not bad if you consider commercial designs that cost thousands will not come close to theis peformance. Its all a relative thing.
Of course what are the intentions of the OP?
doug20 said:
Surprisingly enough a two-way... Crossover around 1,3khz to an 1 inch compression driver, hence an 12 inch woofer to match dispersion.
Im moving my current system (15 inch woofer) to a smaller room, so a smaller speaker is preferable. At the same time I would limit my speaker expenses a bit. The TD woofers are more than double the price then the Faital incl. shipping to Norway.
It is possible for me to wait and save some money for the TD woofers, but as mentioned, ive been thinking of cutting down my speaker expenses a little..
Me too
but I already have the TD12Ms.What CD/waveguide?
NeoDan is trying the Faital 12PR300 over on HTGuide.com, he has measurements too, it looks like a cheap alternative!
http://www.htguide.com/forum/showthread.php4?t=33529&page=3&pp=35
I wouldn't call that a cheap alternative. Certainly cheap, but it's as dissimilar as any 15" could be from the TD15M. It is highly restricted in output and bandwidth, would require a lot more crossover work, and has obvious resonances as John noted.
As to not noticing the difference in home use..... I think that's preposterous. It's not only at high output that a good motor makes a big difference. And it's not only the motor that's subpar on this unit. The acoustic response is going to sound awful if you try to swap it into any design with any decent 15". It's a guitar speaker, not a home or pro reproducer. Fine for a cab where distortion and peakiness may be desirable, not so much for anything where quality's a concern.
For $60 you can get the NHT clearance Jensen 15", a much better unit from all appearances.
With all the solid 15"s out there, these would be near the bottom of my list. Used JBL 2226H can be found pretty cheap with some effort (hawking craigslist for JBL pro speakers), and those are relatively clean up nearer to 2kHz. that's more of an option to my way of thinking.
As to not noticing the difference in home use..... I think that's preposterous. It's not only at high output that a good motor makes a big difference. And it's not only the motor that's subpar on this unit. The acoustic response is going to sound awful if you try to swap it into any design with any decent 15". It's a guitar speaker, not a home or pro reproducer. Fine for a cab where distortion and peakiness may be desirable, not so much for anything where quality's a concern.
For $60 you can get the NHT clearance Jensen 15", a much better unit from all appearances.
With all the solid 15"s out there, these would be near the bottom of my list. Used JBL 2226H can be found pretty cheap with some effort (hawking craigslist for JBL pro speakers), and those are relatively clean up nearer to 2kHz. that's more of an option to my way of thinking.
badman said:
Of course this is all moot for the original poster.. but:
1. An "alternative" does not = a "copy".
2. They have very similar T/S param.s - fundamentally in many respects they are *similar* (though again, not equal nor attempting to be).
3. I've never stated "not noticing the difference in home use". My response was with respect to John's dismissal of the CB15, and such broad generalities as: "if you're looking for an alternative to be used in a real speaker that actually exists, they won't even come close." Such a statement is poor marketing blather. The fact remains that because it is a bass driver, it's likely to be used as a bass driver and that it does have substantially similar T/S param.s - THAT makes it a "close" alternative, though again a cheap one.
4. Sure *if* we substantially "widen the field" there are plenty of other alternatives, but not one that I can think that *might* serve as a "drop-in" replacement for a specific enclosure and achieve a similar targeted freq. response.
Fundamentally, in the most important respect, they're very different.
The response curve. It's not only far less extended, it's extremely peaky, and that WITH smoothing.
Also, the Le is misleading. The TD15M has much flatter impedance, where the significant (looks more like 3.3 than .33 to me) rise on the impedance in the eminence would make crossover design much harder. Did you even bother to check the datasheet, or did you just compare the T/S?
<snip>
On the contrary for most domestic use applications it will in fact come close.
</snip>
Bologna. It's a serviceable guitar speaker, nothing more. It was never meant for this app. Look at the tragic impedance profile. I'm not against a bargain, but between the big peak (and it's probably worse than it looks) and the significant amounts of breakup and poor motor (intended to distort and be overdriven), it has no place in a speaker that would eventually house a decent high fidelity driver.
The response curve. It's not only far less extended, it's extremely peaky, and that WITH smoothing.
Also, the Le is misleading. The TD15M has much flatter impedance, where the significant (looks more like 3.3 than .33 to me) rise on the impedance in the eminence would make crossover design much harder. Did you even bother to check the datasheet, or did you just compare the T/S?
<snip>
On the contrary for most domestic use applications it will in fact come close.
</snip>
Bologna. It's a serviceable guitar speaker, nothing more. It was never meant for this app. Look at the tragic impedance profile. I'm not against a bargain, but between the big peak (and it's probably worse than it looks) and the significant amounts of breakup and poor motor (intended to distort and be overdriven), it has no place in a speaker that would eventually house a decent high fidelity driver.
badman said:
Pray tell, what is the "most important respect"?
If you believe a Bass driver's mid-treble response is the most important, then perhaps I'd agree with your assessment of the CB15. IMO such a perspective doesn't make much sense for the average application. Sure, not having an extended and useful high freq. response is more limiting.. but we have already gone over that (i.e. there will always be limitations, but in this instance limitations that can be effectively dealt with for an average application).
And this "logic":
"a *bass* guitar speaker is serviceable as only a bass guitar speaker",
-is a "glittering generality".
Try looking at the driver objectively. Virtually all of the issues you have raised directly concern the high freq. performance of the driver, concerns that effectively vanish depending on the design and implementation.
Now if you were to object to the driver in a design that crosses-over near 1 kHz and/or utilizes a "shallow" low-pass filter, then sure I'd fully agree with you.
Further if you were to say that the *average* output demanded of the loudspeaker consistently exceeded 100 db a 100 Hz, then again - I'd fully agree with you.
ScottG said:
A guitar speaker generally IS only useful for guitar amps. The rising response is a problem for any usage where a flat frequency response is desirable, as it requires a considerable amount of extra care in crossover design. The built-in distortion generation is also not desirable,
Further, the question of the filter is a big part of the issue here. This particular driver is going to dramatically change parameters with excursion, and that's going to make your filter design 'shift'. Further, the significant peak, the fact that the impedance IS a very inductive one (no matter what eminence claims). As an example, I'm looking at the impedance sweep of a JBL 2213. This driver has a spec'd Le of .6 (measured, .6157), but reaches an impedance of 20 ohms only at 7k. The eminence reaches this impedance at only 1400Hz. This dynamic impedance, along with the cheap motor, make filter design at speaker level very problematic, not just at 2k, but for anything but a steep line-level filter. Speaker level filters of the type commonly used for this task would manage the high inductance, breakup/resonance ripples, and dynamic impedance very poorly indeed.
This speaker is a troublemaker. One that is hard to design (well) around.
I have been looking at Faital 18FH500 fore quite some time now
Despite the critical words from Jonn, Im certain this 18" is a fine woofer fore hifi
Should I consider another Faital woofer it would without doubt be W15N8-350
Its special in having light 85gr cone, yet still low 32hz Fs(in pro terms)
Drawback is the short 5mm(p-p) Xmax
Be aware that very many 12" PRO "woofers" are intended fore high SPL low midrange
Those will have a SPL drop below 500hz
If intended for bass duties they will always be of lower sensitivity
As I wont use nothing bigger than 8" fore midrange, I rate those biggies fore bass only
I also strongly consider PrecisionDevices PD1850
And I may just let it go and order from AE, but no less than 15"
Good 12" though are not many, and AE seem to have very strong carts here
Despite the critical words from Jonn, Im certain this 18" is a fine woofer fore hifi
Should I consider another Faital woofer it would without doubt be W15N8-350
Its special in having light 85gr cone, yet still low 32hz Fs(in pro terms)
Drawback is the short 5mm(p-p) Xmax
Be aware that very many 12" PRO "woofers" are intended fore high SPL low midrange
Those will have a SPL drop below 500hz
If intended for bass duties they will always be of lower sensitivity
As I wont use nothing bigger than 8" fore midrange, I rate those biggies fore bass only
I also strongly consider PrecisionDevices PD1850
And I may just let it go and order from AE, but no less than 15"
Good 12" though are not many, and AE seem to have very strong carts here
This response:
"A guitar speaker generally IS only useful for guitar amps. The rising response is a problem for any usage where a flat frequency response is desirable, as it requires a considerable amount of extra care in crossover design. The built-in distortion generation is also not desirable,"
I agree with everything in this statement as it applies generally to "guitar" speakers when used in loudspeakers.
On the other hand:
The CB15 is a *bass* guitar driver, NOT A "GUITAR SPEAKER".
Yes, it has linear distortion at the top of it's pass-band, which freak'n yet again should most certainly be factored into it's use. With the inductive rise it is also likely to have increased levels of non-linear distortion at the top of it's pass-band (..and dido.)
Same song, 4th verse, same as the first.
.........................................................
This statement:
"Further, the question of the filter is a big part of the issue here."
Agreed. It *is* an important issue.
Same song, 5th verse, same as the first.
..........................................................
This statement:
"This particular driver is going to dramatically change parameters with excursion, and that's going to make your filter design 'shift'.
Where are we positioning the low-pass filter? What's the "slope" for that filter? Will the filter include a Zobel section if necessary (and what would be deemed "necessary")? How much will the driver shift impedance within the confines of it's linear excursion at the crossover's position (..and of course what will the impact be with the filter)?
These are ALL basic questions that need to be resolved in most designs that include a crossover. They are also ALL questions pertaining to the upper freq. response of the driver, where again..
Same song, 6th verse, same as the first.
...........................................................
This statement:
"This dynamic impedance, along with the cheap motor, make filter design at speaker level very problematic, not just at 2k, but for anything but a steep line-level filter."
Is relationally/contextually *nearly* identical to the previous statement. However here the additional conclusion of:
"..make filter design..very problematic..for anything but a steep line-level filter."
Is not necessarily true. (..it may be, and it may not be - depends on the design.) Again though, this pertains to the upper freq. response of the driver, and..
Same song, 7th verse, same as the first.
............................................................
These statements:
"Speaker level filters of the type commonly used for this task would manage the high inductance, breakup/resonance ripples, and dynamic impedance very poorly indeed."
"This speaker is a troublemaker. One that is hard to design (well) around."
Are all purely opinion and when dealt with correctly form an erroneous conclusion. And yet again, are all pertaining to the upper freq. response of the driver, and..
Same song, 8th verse, same as the first.
............................................................
You don't like the "looks" of the driver? FINE. You think it won't perform well in any reasonable design? ACCEPTED. You would caution others to stay away from using it? Perfectly ACCEPTED.
But please, if you ever have problems with my statements then try to "stay within" the context of those statements. The bulk of your problems with this driver I originally excepted with both express and implied caveats.
"A guitar speaker generally IS only useful for guitar amps. The rising response is a problem for any usage where a flat frequency response is desirable, as it requires a considerable amount of extra care in crossover design. The built-in distortion generation is also not desirable,"
I agree with everything in this statement as it applies generally to "guitar" speakers when used in loudspeakers.
On the other hand:
The CB15 is a *bass* guitar driver, NOT A "GUITAR SPEAKER".
Yes, it has linear distortion at the top of it's pass-band, which freak'n yet again should most certainly be factored into it's use. With the inductive rise it is also likely to have increased levels of non-linear distortion at the top of it's pass-band (..and dido.)
Same song, 4th verse, same as the first.
.........................................................
This statement:
"Further, the question of the filter is a big part of the issue here."
Agreed. It *is* an important issue.
Same song, 5th verse, same as the first.
..........................................................
This statement:
"This particular driver is going to dramatically change parameters with excursion, and that's going to make your filter design 'shift'.
Where are we positioning the low-pass filter? What's the "slope" for that filter? Will the filter include a Zobel section if necessary (and what would be deemed "necessary")? How much will the driver shift impedance within the confines of it's linear excursion at the crossover's position (..and of course what will the impact be with the filter)?
These are ALL basic questions that need to be resolved in most designs that include a crossover. They are also ALL questions pertaining to the upper freq. response of the driver, where again..
Same song, 6th verse, same as the first.
...........................................................
This statement:
"This dynamic impedance, along with the cheap motor, make filter design at speaker level very problematic, not just at 2k, but for anything but a steep line-level filter."
Is relationally/contextually *nearly* identical to the previous statement. However here the additional conclusion of:
"..make filter design..very problematic..for anything but a steep line-level filter."
Is not necessarily true. (..it may be, and it may not be - depends on the design.) Again though, this pertains to the upper freq. response of the driver, and..
Same song, 7th verse, same as the first.
............................................................
These statements:
"Speaker level filters of the type commonly used for this task would manage the high inductance, breakup/resonance ripples, and dynamic impedance very poorly indeed."
"This speaker is a troublemaker. One that is hard to design (well) around."
Are all purely opinion and when dealt with correctly form an erroneous conclusion. And yet again, are all pertaining to the upper freq. response of the driver, and..
Same song, 8th verse, same as the first.
............................................................
You don't like the "looks" of the driver? FINE. You think it won't perform well in any reasonable design? ACCEPTED. You would caution others to stay away from using it? Perfectly ACCEPTED.
But please, if you ever have problems with my statements then try to "stay within" the context of those statements. The bulk of your problems with this driver I originally excepted with both express and implied caveats.
I'm sorry if my first reply came off as too defensive or anything. The thread is titled AE TD12M cheap alternative. Therefore we'd be looking at an application where the TD12M is used. This would mean wide band, high efficiency, high power handling, and high excursion for a driver with this efficiency. In that case, there really are no real alternatives that come close at any cost. I could make a similar driver without shorting rings in China for less than half the cost that would on paper have identical parameters, but keeping everything else equal it still wouldn't be an alternative for the applicaton of a TD12M.
If you take out high efficiency you look at the TD12S, H, or X. There are a few options out there by AudioTechnology and ATC that could do similar, although still with lower excursion, lower power handling, double the inductance, and also double the cost.
The issue with this is that the non-linear distortion is not only created at the top of it's passband. It is created at all frequencies. The higher the excursion, the more Le variance and the more distortion at all frequencies from this. The higher the current, higher the flux modulation. Both of these have some pretty serious effects. Add in a very peaky BL curve that drops quickly with excursion as well.
In terms of distortion the klippel poster here gives a very good overview of what symptoms are related to a specific non-linearity. In reality, Le(x) and Le(i) are huge contributors to distortion.
http://www.klippel.de/download/Nonlin/Klippel_nonlinearity_poster.jpg
One thing to note is that no matter what filter you use, a cone breakup, dustcap resonance, etc will still be an issue unless you cross well below it. This is very much the case in high distortion drivers. For example, say a driver has a bad resonance at 3KHz. You cross over 1500hz at 24dB, so the input at 3KHz is 24dB down and the resonance isn't an issue right? The problem is when you have a huge amount of harmonic distortion. The cone resonance is not just excited by fundamental but by the harmonics from 1500hz, 750hz, etc. A high level harmonic of 1500hz can excite that 3KHz resonance to a very audible level and your xover can do nothing about it.
The impedance can change drastically. If it had only effects at high frequencies it would be easy to deal with. The more components (higher slope) the more it is changed by the impedance shift. Take a look at 2 drivers I used for comparison before. The top curve is the IDMAX which is a car audio woofer, but regardless we can look at it for comparison. Orange is at rest and when the coil is on the inward stroke. Blue is what happens when the coil comes forward and inductance drops. Take 500hz as an example. There is an 8dB difference in response between inward and outward stroke. This is huge in terms of the impedance change. Any Zobel applied to that is going to also be affected by the change in impedance. Also of note, look at the difference in response 50-100hz. While some would claim crossing low enough makes it a non-issue, this inductance affects the response on the low end also. A passive filter that works so well based on the T/S parameters only works properly when the driver is not moving.
Then look at the bottom curve which shows an AV12X. This is with low vs high excursion as well. However since inductance is so low, and so linear, there is virtually no difference under 1KHz. Your filters now apply the same at all excursions.
![url]](/community/proxy.php?image=http%3A%2F%2F%5Burl%5Dhttp%3A%2F%2Fwww.aespeakers.com%2Fpics%2FAV12X_vs_IDMAX_inductance.png%5B%2Furl%5D&hash=2c8a29f550fc881d89e7c615a91b6be0)
Another extreme example is our old HE15. This was designed prior to our manufacturing in house. Look at how drastically the inductance changes response in the 40-100hz region.
Again see the response above regarding the effects at all frequencies based on inductance change. The flux modulation caused by eddy currents causes effects at all frequencies as well.
John
If you take out high efficiency you look at the TD12S, H, or X. There are a few options out there by AudioTechnology and ATC that could do similar, although still with lower excursion, lower power handling, double the inductance, and also double the cost.
ScottG said:
The issue with this is that the non-linear distortion is not only created at the top of it's passband. It is created at all frequencies. The higher the excursion, the more Le variance and the more distortion at all frequencies from this. The higher the current, higher the flux modulation. Both of these have some pretty serious effects. Add in a very peaky BL curve that drops quickly with excursion as well.
In terms of distortion the klippel poster here gives a very good overview of what symptoms are related to a specific non-linearity. In reality, Le(x) and Le(i) are huge contributors to distortion.
http://www.klippel.de/download/Nonlin/Klippel_nonlinearity_poster.jpg
One thing to note is that no matter what filter you use, a cone breakup, dustcap resonance, etc will still be an issue unless you cross well below it. This is very much the case in high distortion drivers. For example, say a driver has a bad resonance at 3KHz. You cross over 1500hz at 24dB, so the input at 3KHz is 24dB down and the resonance isn't an issue right? The problem is when you have a huge amount of harmonic distortion. The cone resonance is not just excited by fundamental but by the harmonics from 1500hz, 750hz, etc. A high level harmonic of 1500hz can excite that 3KHz resonance to a very audible level and your xover can do nothing about it.
The impedance can change drastically. If it had only effects at high frequencies it would be easy to deal with. The more components (higher slope) the more it is changed by the impedance shift. Take a look at 2 drivers I used for comparison before. The top curve is the IDMAX which is a car audio woofer, but regardless we can look at it for comparison. Orange is at rest and when the coil is on the inward stroke. Blue is what happens when the coil comes forward and inductance drops. Take 500hz as an example. There is an 8dB difference in response between inward and outward stroke. This is huge in terms of the impedance change. Any Zobel applied to that is going to also be affected by the change in impedance. Also of note, look at the difference in response 50-100hz. While some would claim crossing low enough makes it a non-issue, this inductance affects the response on the low end also. A passive filter that works so well based on the T/S parameters only works properly when the driver is not moving.
Then look at the bottom curve which shows an AV12X. This is with low vs high excursion as well. However since inductance is so low, and so linear, there is virtually no difference under 1KHz. Your filters now apply the same at all excursions.
Another extreme example is our old HE15. This was designed prior to our manufacturing in house. Look at how drastically the inductance changes response in the 40-100hz region.
Again see the response above regarding the effects at all frequencies based on inductance change. The flux modulation caused by eddy currents causes effects at all frequencies as well.
John
I agree with Scott here.
I like using prosound style drivers in domestic application because of their high sensitivity, low distortion and build quality. Quite some audio friends around also tend to be the same way. (and they got 'better' gears than mine, e.g., Altecs, TADs, and the likes... )
However I've found a 'problem' with this - prosound drivers in domestic uses - they seem to fully wake up only when SPL is higher than a particular point (of course the degrees are varied with different drivers). I myself have been using 18" woofers of EV and Emenence. They all like high SPL playback and somewhat dumb in low volume. (they are not long excursion woofers, with only 5~6mm Xmax and maybe never used up)
I'd guess it's some kind of nonlinearities (not sure in suspension or motor). Too much inertia to be overcome in the very first tiny movement? I'm not sure. No expert.
I see them as those high power but also relatively heavy cars. They perform excellently in the high speed range but are not as agile as those lighter cars in slower and smaller actions. This analogy is all too rough, I know, but you got the idea.
So.... do those non-optimal motors in my not-so-good PA woofers cause any problems in power compressions or any other issues come with 'severe abuses'? I don't think so at all. In domestic use, they barely move, merely just-waken-up. I've used 6W 300B SE amp with 2 Eminence 18" woofers per side in a room of 30 sq. meters with 3.2m ceiling height plus some doorways towards other spaces. With that tiny 6W, the bass overwhelmed and shook the entire house, not only 'that' room.
I don't have instruments to measure distortions or the likes, so I'm not in the position to tell how they actually performed. I was just submerged by the overwhelming acoustic power, felt like I was in a giant washing machine. That actually made me very upset and also feel guilty in those short periods. How often do I do such "firepower exhibition" in my own place (within crowded residential area) ? You tell me. (I'm not insane, by the way.)
Later I tried OB with these monsters and they sounded much better. In addition to no box coloration, the bigger 'range of motion' might also help, I guess.
As to those 'should-be-banned' guitar drivers, I actually like them. Way too short of Xmax does not bother me at all as long as I use them in midrage. Those peaky devils on the FR chart are also easily tamed by some 'minor' mods -- some PVA glue coating on the cone and dust cap removal. I've used such a modded 12" guitar driver as midrange in about 200-3kHz on OB and it sang pretty well. Of course it's not perfect (nothing is), but it surely out-performed many many many many many many many 'Hi-Fi" drivers out there in many many ways and is much cheaper. Unlike those overly strong PA woofers, guitar drivers play quite well in low SPL (because of the light cones?).
Hey, was I cheating by modding the drivers? Well, you can say that, but this is a DIY forum. I got so much fun with it and also have enjoyed countless music through it. So, what's wrong? I can't see any.
Don't get me wrong, I admire AE/TD drivers SO MUCH. Before the "Store" section is up in the web site, I had enquired for quotation and ALMOST placed an order, just -><- this close. I KNOW they are excellent drivers even before I actually see and hear them. Such things bring us so much 'feel good factor' in addition to their already excellent performance. Just like a Ferrari (or the likes).
Well, a Ferrari (and/or other 'good' stuff) is surely admirable, but I can live without it.
Sooooo...., back to the original post, I'd say give it a try. Don't worry about any 'risk', there won't be any. Point is, do not see it as a 'cheap alternative' of something. Take it what it is and work from there, you'll have a good result and good time along the process.
I like using prosound style drivers in domestic application because of their high sensitivity, low distortion and build quality. Quite some audio friends around also tend to be the same way. (and they got 'better' gears than mine, e.g., Altecs, TADs, and the likes... )
However I've found a 'problem' with this - prosound drivers in domestic uses - they seem to fully wake up only when SPL is higher than a particular point (of course the degrees are varied with different drivers). I myself have been using 18" woofers of EV and Emenence. They all like high SPL playback and somewhat dumb in low volume. (they are not long excursion woofers, with only 5~6mm Xmax and maybe never used up)
I'd guess it's some kind of nonlinearities (not sure in suspension or motor). Too much inertia to be overcome in the very first tiny movement? I'm not sure. No expert.
I see them as those high power but also relatively heavy cars. They perform excellently in the high speed range but are not as agile as those lighter cars in slower and smaller actions. This analogy is all too rough, I know, but you got the idea.
So.... do those non-optimal motors in my not-so-good PA woofers cause any problems in power compressions or any other issues come with 'severe abuses'? I don't think so at all. In domestic use, they barely move, merely just-waken-up. I've used 6W 300B SE amp with 2 Eminence 18" woofers per side in a room of 30 sq. meters with 3.2m ceiling height plus some doorways towards other spaces. With that tiny 6W, the bass overwhelmed and shook the entire house, not only 'that' room.
I don't have instruments to measure distortions or the likes, so I'm not in the position to tell how they actually performed. I was just submerged by the overwhelming acoustic power, felt like I was in a giant washing machine. That actually made me very upset and also feel guilty in those short periods. How often do I do such "firepower exhibition" in my own place (within crowded residential area) ? You tell me. (I'm not insane, by the way.)
Later I tried OB with these monsters and they sounded much better. In addition to no box coloration, the bigger 'range of motion' might also help, I guess.
As to those 'should-be-banned' guitar drivers, I actually like them. Way too short of Xmax does not bother me at all as long as I use them in midrage. Those peaky devils on the FR chart are also easily tamed by some 'minor' mods -- some PVA glue coating on the cone and dust cap removal. I've used such a modded 12" guitar driver as midrange in about 200-3kHz on OB and it sang pretty well. Of course it's not perfect (nothing is), but it surely out-performed many many many many many many many 'Hi-Fi" drivers out there in many many ways and is much cheaper. Unlike those overly strong PA woofers, guitar drivers play quite well in low SPL (because of the light cones?).
Hey, was I cheating by modding the drivers? Well, you can say that, but this is a DIY forum. I got so much fun with it and also have enjoyed countless music through it. So, what's wrong? I can't see any.
Don't get me wrong, I admire AE/TD drivers SO MUCH. Before the "Store" section is up in the web site, I had enquired for quotation and ALMOST placed an order, just -><- this close. I KNOW they are excellent drivers even before I actually see and hear them. Such things bring us so much 'feel good factor' in addition to their already excellent performance. Just like a Ferrari (or the likes).
Well, a Ferrari (and/or other 'good' stuff) is surely admirable, but I can live without it.
Sooooo...., back to the original post, I'd say give it a try. Don't worry about any 'risk', there won't be any. Point is, do not see it as a 'cheap alternative' of something. Take it what it is and work from there, you'll have a good result and good time along the process.
Hello John,
I found a mistake on your web site:
http://aespeakers.com/shop/catalog/...id=71&osCsid=7ee58a4009cb7cc10e98020efd6095fa
Quantity............. 1+.......... 389+.........419+
Price for each. $449.00... $10.00 ......$2.00
Your savings................... - 98% .......100%
This should be wrong. Or I'd like to order 420 of them
I found a mistake on your web site:
http://aespeakers.com/shop/catalog/...id=71&osCsid=7ee58a4009cb7cc10e98020efd6095fa
Quantity............. 1+.......... 389+.........419+
Price for each. $449.00... $10.00 ......$2.00
Your savings................... - 98% .......100%
This should be wrong. Or I'd like to order 420 of them
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