I recently bought some NOS Realistic 40-1289A mid tweeters.They are sealed back 3 inch paper coned mid tweeters with a quoted response of 700Hz to 20,000 Hz.A 16uF cap is used as first order crossover.
I am quite shocked by how good these sound .They are also extremely easy to use and integrate with say typical 88-90db 8 inch woofers.
It seems to me using this sort of driver avoids common problems associated with trying to cross over at say 2000-300Hz where our hearing is far more sensitive .
Which beggars the question why aren't these mini point source type drivers more common?
Any suggestions of modern equivalents.?I have noted there are plenty of small so called full range drivers available but they tend to be low sensitivity and seem to have pretty ragged high frequency responses.
I am quite shocked by how good these sound .They are also extremely easy to use and integrate with say typical 88-90db 8 inch woofers.
It seems to me using this sort of driver avoids common problems associated with trying to cross over at say 2000-300Hz where our hearing is far more sensitive .
Which beggars the question why aren't these mini point source type drivers more common?
Any suggestions of modern equivalents.?I have noted there are plenty of small so called full range drivers available but they tend to be low sensitivity and seem to have pretty ragged high frequency responses.
Yes a couple there although sensitivity is lowish.You could use two of them to increase that though.In that regard 8 ohm would be better so you could use them wired in parallel.
A half-wavelength at 20 kHz is only 8.5 millimetres, or about one-third of an inch. So a 3-inch tweeter is some nine half-wavelengths in diameter at 20 kHz. This is so big that if a 3" tweeter did emit 20 kHz sound, it would beam like a searchlight!
Normal human ears don't really hear 20 kHz until it is so loud that it's at the threshold of hearing damage, so we really don't need to worry too much about it. Still, we want at least 10 kHz out of our tweeters for reasonably good quality audio. And even at 10 kHz, a 3" tweeter is four or five times bigger than it should be.
And that's the main problem. A 3" tweeter is too big to disperse high treble.
Additional problems are that 3" is also big enough to suffer from cone breakup long before it gets to 20 kHz, and the requirement to cope with mid frequencies as well forces the moving part to be heavier than a dedicated small tweeter, which then causes poor sensitivity compared to a typical small, light, 1" tweeter.
-Gnobuddy
There is usually a central dome .The Realistic has a 20mm hard dome as well as the 50mm cone.Would that not extend the frequency response?
It is 3 inch nominal size but the actual cone diameter is more like 50mm/2 inch.
The sensitivity thing is OK. If the speaker is not soffit fit, your woofer will lose about 3dB below the baffle step, so after eq, you have a roughly 85dB woofer. Your mid tweeter only needs to be 85dB to match.
The FAST threads on the full range section cover this & give many driver options.
The Tymphany NE65 seems like an OK option (I personally like it, and the range measures well).
If using a fairly sensitive LF driver, I'd suggest 'cheating' by using a single 4 ohm midtweeter and 8 ohm woofer.
Or horn load the midtweeter.
Or both. I do both
Hollowboy,
I went through my full range driver phase about ten years ago.That was very interesting but I think I am getting much better sound out of my two way using the Realistic mid/tweeter than I ever got out of larger full/wide range drivers.At least I am getting proper bass and proper treble and none of the scratchy and shouty sort of presentation wizzer coned drivers like Lowthers and Fostex seem to exhibit.
I will check out the NE65.Visaton also do some fibreglass 4 inch water proof /marine drivers that seem to measure well about 300Hz to 16000Hz.
Kinda sorta...the hope is that the bigger, heavier outer cone stops vibrating when the frequency gets high enough, leaving the centre dome to do its job cleanly. But in practice, as frequency goes higher and higher, the outer cone breaks up in multiple modes, and bits and pieces of it flap wildly and uncontrollably around, erratically adding and subtracting to the sound waves from the central dome.
So you usually get exactly that erratic, ragged frequency response you mentioned in one of your earlier posts. And if you also have polar plots, they will usually show the same kind of ragged and erratic behaviour.
"Hard" dome tweeters are troublesome things, too. Unless they are made of something exotic like titanium or ceramic, they often have a violent break up mode or two within the audio band. If you have a good enough measurement microphone, you can sometimes see big narrow spikes in the frequency response at these "oil-can" breakup modes.
The traditional silk-dome tweeter is less stiff, but silk is also lighter than titanium, and the breakup modes are usually gentler and better controlled because there is a lot more internal damping in silk than in metal. Which is why silk-dome tweeters have a reputation for being easier to listen to (they cause less ear-fatigue.)
I'm no speaker designer, but I worked with a couple of professionals in that field right around the time active crossovers were starting to show up in powered studio monitors. What we all learned from the experience of designing both active and passive crossovers, was that it is really hard to design even a half-way decent passive crossover network, but using active crossovers and one power amp per driver, the job is made 90% or 95% easier.
With a reasonable active crossover design, straight out of the box, you get a decent crossover, which is very important to DIY speaker builders who don't have access to $5000 Bruel & Kjaer measurement microphones flat from 4 Hz to 70 kHz, along with proper anechoic chambers to measure speakers in.
So DIY speaker design with separate drivers is not as difficult as it used to be. With active crossovers and cheap chip amps, it probably won't be hard to do better than a single 3" mid-tweeter driver. But it will be a much more complex solution, unfortunately!
If the 3" mid will go cleanly up to 4kHz or 5 kHz, then there is the option to set the crossover frequency up there, where the ear is less fussy. The tweeter only has to deal with the top couple of octaves in the audio band, and the midrange doesn't have to struggle to double as a tweeter.
-Gnobuddy
That's essentially my experience / opinion too.
I'm now more keen on wide band drivers that don't have a whizzer.
Chuck some numbers into this:
Piston Excursion calculator
A 2" driver with 1mm excursion can hit 99dB @ 500Hz.
A 8" driver with 6.5mm excursion can hit 99dB @ 50Hz.
Therefore I think there's no need to go bigger than about 2" with the mid tweeter.
I have been down the active/digital crossover /DSP route too but never got great sound compared to a well designed passive crossover .It seems you can get it good but not great.
The sound I am getting with the mid/tweeter is pretty close to great.Better than my Kairos two way and three way for example -and that is very good[but again not great].
The sound I am getting with the mid/tweeter is pretty close to great.Better than my Kairos two way and three way for example -and that is very good[but again not great].
I know they are popular now, but I experimented with digital crossovers in the late 1990s, and I *never* managed to get good imaging with them.
Digital crossovers usually involve many milliseconds of latency, which is enough time for sound waves to travel several feet. Unless you are very precise about exactly matching the latency to each driver, you can end up with the equivalent of a tweeter that's mounted four or five feet ahead - or behind - the midrange.
Not surprisingly, if that happens, the sound from the two drivers will never integrate properly, and the speaker will never sound good.
Under some conditions, people with good hearing can sometimes hear a difference in stereo imaging if the tweeter and midrange are only one inch away from proper time alignment. That's equivalent to a time misalignment of less than 80 micro seconds. If you're using separate DSP and digital crossovers for each driver, this is the level to which the various speaker outputs should be time-aligned. I don't know how easy this is to achieve in practice.
Though they are not as easy to tweak, I like old-fashioned active analogue crossover networks - a fistful of opamps, resistors, and capacitors. With 1% resistors and capacitors, frequency responses are very accurate. Latencies are usually only a few microseconds, thousands of times smaller than for digital crossovers, so it is relatively easy to time-align the tweeter and midrange by putting the appropriate step in the front baffle. Or you can use a few more opamps and build an all-pass filter to provide the same time alignment electronically, and use a flat speaker front baffle.
Now my ears are a couple of decades older than they were when I worked with those speaker designers, so I'm sure I won't hear some of the fine details I could hear back then with young ears.
-Gnobuddy
Can you not measure the delay, then adjust for it?
Time alignment
how to time align drivers (with minidsp) ?
The visaton b80, which is slightly bigger at 3.3” seems to be an alternative but not cheap.
B 80 - 8 Ohm | Visaton
B 80 - 8 Ohm | Visaton
The Faital Pro M5N 8-80.
This is also a very interesting mid/lower treble driver with massive sensitivity.
It would need support of a bullet or slot tweeter with similar sensitivity above 8000Hz but could sound exceptional covering 5-6 octaves.
https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&cad=rja&uact=8&ved=2ahUKEwj1oOn008vdAhWBOnAKHUxXAboQFjAAegQIBxAB&url=https%3A%2F%2Fwww.faitalpro.com%2Fen%2Fproducts%2FLF_Loudspeakers%2Fproduct_details%2Findex.php%3Fid%3D101010100&usg=AOvVaw1Wg5XBnkUcICSIrIaJqBu-
This is also a very interesting mid/lower treble driver with massive sensitivity.
It would need support of a bullet or slot tweeter with similar sensitivity above 8000Hz but could sound exceptional covering 5-6 octaves.
https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&cad=rja&uact=8&ved=2ahUKEwj1oOn008vdAhWBOnAKHUxXAboQFjAAegQIBxAB&url=https%3A%2F%2Fwww.faitalpro.com%2Fen%2Fproducts%2FLF_Loudspeakers%2Fproduct_details%2Findex.php%3Fid%3D101010100&usg=AOvVaw1Wg5XBnkUcICSIrIaJqBu-
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In principle, sure. In practice, distinguishing 50 uS worth of delay on top of a 5 - 10 mS latency (a baseline that's a couple of hundred times longer than the thing you care about) wasn't that easy. You're trying to spot and correct a 1% or smaller difference between two large quantities. What sort of microphones, measurement environment, and test signals will you need to do this? It turned out to be hard, even with access to a really good measurement mic.
With analog active crossovers, the delay is only microseconds to start with. So now you're trying to spot the difference between 2 and 1, rather than 201 and 200. Much easier.
The other complication I found was that the latency and phase shift in the DSP crossover / EQ isn't necessarily constant; depending on the software implementation, it can change depending on the type of EQ you dial in. One implementation we tried introduced an additional 180 degree phase shift every time you added one more notch or peak into the EQ!
-Gnobuddy
I fixed up some old speakers with that type of tweeter for my best friend's husband. He was so happy he still has them some 15 years later. So yes, those old drivers do have a certain goodness about the sound. Why did they die?
- Once you get to higher prices for the raw drivers, other types/materials can simply have more delicacy of sound.
- Fashion! Domes became more nouveau, and "cooler" so those old-school tweeters seemed cheap and old.
I don't think you have many true equivalents today. Most all the stuff you'll find are attempting to be full range (or nearly), not tweeters. And the efficiency of those does tend to be low.
Yes the "certain goodness" is obvious.There is a bit of classic Tannoy dual concentrics about them.That same sense of coherence and timing.They also seem to integrate with a woofer using just a series inductor so you get all first order crossovers which also helps with phase coherence.
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Having the xmax to support 500Hz at sufficient volume is one thing. Having a mechanical arrangement which remains linear at that excursion is another thing. Most 2" drivers start becoming very non-linear below about 800Hz-1kHz if you push them >95dB/1m.
The best i've seen is the Peerless TC7FD00-04. Cross at about 800Hz LR4.
The best i've seen is the Peerless TC7FD00-04. Cross at about 800Hz LR4.
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This Peerless could also be OK.
Again more of a wide range driver than a mid/tweeter but could work fine as mid/tweeter if you cut off the bass below about 500Hz or so.
86.5 db /watt sensitivity which is higher than most of the others.
https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&cad=rja&uact=8&ved=2ahUKEwjt993y3tXdAhXBdd4KHYFNAlgQFjAAegQICBAB&url=https%3A%2F%2Fwww.parts-express.com%2Fpeerless-by-tymphany-830985-2-1-2-full-range-woofer--264-1050&usg=AOvVaw32Wpew6OAeJv2i_GVaZ0Ui
Again more of a wide range driver than a mid/tweeter but could work fine as mid/tweeter if you cut off the bass below about 500Hz or so.
86.5 db /watt sensitivity which is higher than most of the others.
https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&cad=rja&uact=8&ved=2ahUKEwjt993y3tXdAhXBdd4KHYFNAlgQFjAAegQICBAB&url=https%3A%2F%2Fwww.parts-express.com%2Fpeerless-by-tymphany-830985-2-1-2-full-range-woofer--264-1050&usg=AOvVaw32Wpew6OAeJv2i_GVaZ0Ui
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