What specifically did they say won't work that did? If there's some misunderstanding on my part of what a driver can (0r should) and can't (Or shouldn't) do, I'd love to be enlightened. Especially as it pertains to output, which is my problem with your system requirement.
One more thing- Xmax is about the most useless driver spec there is. In no way does this single number tell anyone what amount of distortion a specific driver will make at a given SPL. Yes when Xmax values are exceeded we all know distortion will increase but in no way does Xmax provide a clear limit. Saying Xmax is automatically the limit simply shows lack of both knowledge and experience with emphasis on mathematical models and theory and not of what actually happens in the real world with real transducers.
Keep bringing those off the shelf speakers to this thread. Have seen a lot of interesting things. Thanks-
Sure, there are very different behaviors outside of Xmax. But here's the simple truth- you're limited as to how much coil you can have in the gap and how efficiently that allows the assembly to operate. You're limited by clearance tolerance, practicalities of magnet, motor, coil, and even frame design. Steel saturates, magnet width must be less than frame inside diameter for mounting practicality. The maximum sensitivity in a ceramic and steel motor is achieved with a coil the length of a saturated top plate, in the smallest gap possible. That's why we see 2mm Xmax numbers or less in the high efficiency small drivers. Exceeding Xmax by 50% is very different than exceeding it by 350-400%. You're limited by the suspension and assembly, as well as tolerance and material stiffness. The higher xmax your suspension has the more rocking modes can be introduced and the larger you have to make the gap to avoid rubbing.
So there are severe restraints there, and coil weight and diameter vs. power handling is the other issue which is just as limiting.
IM distortion primarily. A quarter wavelenth is an extreme case, but you're still launching small waves from a massively exurting cone.
I see your desire to run only to 2k which does reduce the IM concern quite a bit. You talk of controlled directivity, what on earth will you have above such a small driver if not a horn? I'm not aware of any tweeters that would be both omni at 2k and above, as well as being able to manage any high power/output operation. And if a horn, why wouldn't you want the 5" to taper to a closer matched beamwidth?
6.5" to 120Hz in a high output pro speaker? Which please?
The constraints above are why all high sensitivity tiny drivers are very Xmax, power handling, and highly damped in the lower frequencies. You haven't yet found a single driver that even comes close to your requirements, and you won't. The state of the technology doesn't allow it.
Not just that but do it in a small box <6" wide!
I could see someone managing 109dB from a 99dB w/m driver at 150hz with a ridiculous field coil, it would sound atrocious though It would also be extremely difficult to make, every piece would have to be custom, and the small size requirement for the speaker makes a field coil out of the question. And even with mass production, if it were adopted for every studio in the world, it would be the most expensive small loudspeaker driver in the world, and quite possibly the most expensive loudspeaker period, including extreme exotica.
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Name it after you!
Well, that is asking a lot. Working on a 5" for 99dB at 200Hz. If it comes out as good as you request (suggest) will name it after you! Maybe a 6½" could do that.
Has anyone ever wondered why there are 99dB woofers and 99dB tweeters and not much in the way of a 99dB low mid? Simply put, IMO it is because no one happens to build one.
Keep on coming with other drivers for reference and possible use. Can always learn from what the other guy did, right?
Any constructive suggestions are always appreciated.
Well, that is asking a lot. Working on a 5" for 99dB at 200Hz. If it comes out as good as you request (suggest) will name it after you!
Maybe a 6½" could do that.Has anyone ever wondered why there are 99dB woofers and 99dB tweeters and not much in the way of a 99dB low mid? Simply put, IMO it is because no one happens to build one.
Keep on coming with other drivers for reference and possible use.
Can always learn from what the other guy did, right?Any constructive suggestions are always appreciated.
Well, that is asking a lot. Working on a 5" for 99dB at 200Hz. If it comes out as good as you request (suggest) will name it after you!
So, you've shifted your requirement by an octave (which is still insufficient). Better but still problematic. Again, you're exceeding any reasonable driver by several times Xmax. That's unacceptable and will lead to significant distortion and eventual failure. You can't have a long throw and maximize sensitivity, and there's no "give" on maximizing sensitivity when you're talking about an undersized driver. You have to go low mms, high Qms, matched coil and gap size and as much magnet as you can get on the frame. You ALSO can't do it without a very low Qts and usually (very) high Fs, making your efficiency in the 100-200Hz range an average of 6-8dB lower than the "nominal" 99dB spec you so covet.
Uh, yeah, they do. They're either 12"s 10"s or 8"s and are available from every prosound company around. They usually have a rising response which is typical for ultra efficiency drivers.
Linear excursion (XMAX)
±0.7mm
And 90dB nominal efficiency at 150Hz. So just shy of 100W to reach 109dB (though if that were only peaks, power handling wouldn't be an issue), and here's the kicker-- >10x xmax to get there.
You'd be just as well going with one of the modern scan speaks who don't have as high an Fs and thus have similar sensitivity at 150, but have some real Xmax.
I don't know that this has been mentioned: Galaxy Audio S5N-8 5" Neodymium Full Range Driver 8 Ohm | Parts-Express.com
it's a little light on specs, but might be worth a try.
Dan
it's a little light on specs, but might be worth a try.
Dan
badman- we all have read your writing of Xmax. Repetition of this refrain is getting old. Please find something useful to write. How about producing an accurate chart or spread sheet so everyone can see the exact Xmax, effective piston diameter, and frequency for a given SPL. That would be useful to the thread. Everyone can see the response graph and spec sheet so you added nothing there either though the graph shows 91dB at 150Hz so your read is clearly wrong. Please quit this thread wrecking negative behavior. You are bringing nothing to light and not bringing new drivers either. Not in the spirit or design of this thread or DIYaudio in general. This thread is about higher efficiency drivers identification please.
Am not in favor of using the Fs resonance to peak the response of the lower frequencies of any driver. Resonance peaking is a bad idea though very popular. Automatically looking for flat rather than lower Q is consider an error here.
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If we order some in maybe I can hook you up cheaper~$40 as the wholesale price is $39. We shall see.
What is so cool is there are some very decent looking drivers out there. Not to many but a few. Hope this helps others as much as it has me. Found that one driver I just posted on another thread. Lots of great reading here on DIYaudio!
More great stuff to come (I hope)!
What is so cool is there are some very decent looking drivers out there. Not to many but a few. Hope this helps others as much as it has me. Found that one driver I just posted on another thread. Lots of great reading here on DIYaudio!
More great stuff to come (I hope)!
91dB, oh so different than 90... Anyone with a whit of intelligence can model whatever piston behavior they want. Having 1/2 your coil out of the gap in an evenhung motor does not make decent usable sound.
The monacor has high Qts, I am not talking about using a high Qts driver, and the Scanspeaks are moderate Qts.
Again, there's a reason none meet your criteria or even come close. You've specified an unattainable task. Anyone with real world experience knows this. I have built half a dozen speakers with drivers in the size range under question operating in the frequency bands under question (and below) in the past 5 years and am very aware of their limits.
Xmax isn't everything but half the coil out of the gap in these designs means high distortion and bad sound. You don't seem to understand the basics of operation in a loudspeaker motor.
here's the older, cheaper version still for sale: Galaxy Audio S5C160-8 5" Full Range Driver | Parts-Express.com
Dan
I don't remember where, but I saw some QC and reliability complaints for these. The first model (95dB Nd motor) is very slick seeming though. Both have Fs in the hundreds, however, and without a very high Qts they'll have issues with sensitivity in the contentious 100-200Hz band
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