midrange/woofer without crossover filter?

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I've noticed a few designs that allow the mid-woofer to roll off naturally without a filter to the tweeter. This is pretty common for full range drivers that are augmented by a supertweeter. I think I recall the the original Egglestonworks Andre doing this with the Morel MW166, I haven't read as much about later revisions. And here the SCM634 is used full range: 6moons audio reviews: Eltim Supreme 614 Solo

Has anyone found good drive units to run unfiltered to a tweeter?
 
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sorry for poor pic quality, its just a phone in the dark kitchen, my canon is packed for rockies
 

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I actually have a couple of mids right now that I bought awhile back. 5" alnico paper cone drivers that were extra left over from an oem order for Nola (Alon back then) sold by Madisound. Designed for dipole use in a 3-way. They are good from 150-10,000hz but I never got around to using them in a system. Just ran them unfiltered for a long time.
 
I don't see a point in avoiding XO's. Even if you find a perfect
midwoofer with optimized midrange roll-off and voice coil modified
to counteract the baffle step, you are still relying on the same technology
that acts as a low pass filter, the increased inductance.

Seas A 26 RE4 might be a good candidate for a no need LP.
 
The baffle step is always annoying. The ways to deal with it that I'm aware:
1. Compensation circuit to reduce efficiency above the baffle step frequency.
2. Add in a 2nd identical driver to fill in below the baffle step.
3. Use the step as part of the crossover to a woofer.
4. Dipole operation which is similar but has it's own set of issues.
 
Multiple reasons.
1. Added cost
2. Any crossover components add resistance/capacitance/inductance including extra wire and solder joints, degrading the signal, reducing efficiency and robbing micro-detail.
3. Phase shift and other effects.

I think everyone can make it own choice, but here you've given some too easy theorical argument, that you maybe need to reconsider.

Voicecoil is moving, so electrical parameter of drivers are more or less varying dynamically with level/heat. On the contrary, passive component are a lot more stable when reasonnably chosen. Adding inductance for example, make system inductance more linear, and so dynamic frequence response. Driver already got more or less resistance and "loose".
About "robbing micro-detail" argument...looks inside you're amp ! It's yet full of those bad passive component. Even so really high fidelity speaker got inductance/resistor/capacitors...
About phase shift, simulators allows to build passive network that can correct phase problem.

If you want a midrange/or woofer that can cross easily with higher way, you'll probably search for a beautiful natural high freq roll off...that is in fact due to high inductance of big voicoil, with probably no demodulation ring/nor neodinium motor, that is moreover often masking some cone resonnance (easy to see in distortion plot). But a non linear inductance since voicecoil is moving, that moreover since it has low pass effect, has phase shift effect too, but non dynamically linear.

Unless you use remote sensing amplifier (i am ^^), or a current amp, your speaker cable got already some resistance/inductance that the amp have to deal with.

Using not so complex network, you can bypass some resistor loose effect, depending on your network goal.
And in some condition, it is even possible to get some more efficiency in a broadband range with passive network (really special case, but it exist).

You can make all the choice you want to suit your tastes,specifications, and goal in electronic, but real life result will still be based on physical and mathematical properties and not about common belief, or personal taste.

(Lot of edit !) Cabinet are by themself another way to affect frequency response, as impedance transformer effect of horns, bandpass effect of bandpass box loading, complex effect of bass-reflex loading or tapped horn...etc... They have all there own physical property too to deal with.
 
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I just say that real inductor is more linear than voicecoil. Music is not pure sinewave. Speaker has to play on his bandwith his lows and highs at the same time, making inductive low pass variable with deplacement needed for playing his lows at the same time. If this effect is not so much important while respecting xmax, it make speaker with natural roll off less idea than a fullrange + inductor from this point of view.
Remember frequency response mesurement mesure just one frequency at the same time, music content is complex.
 
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By the way, french Melon & Adason members, what about roll off when spl increase with these smooth roll off mids (B&C 8P21e for instance) ?

Which I woud like to know : does they keep the nice transition with the upper driver when dynamic behavior is involved ?


WHat was the name of this famous american 2 ways monitor with no low pass filter in the mid with the tweeter 10/15 years ago ? It ad some Awards in USA !
 
So you'll take poor phase and frequency response over the above list? Your #2 is all fallacy.

Crossovers are always a set of compromises. If well designed then the pros easily outway the cons. You are using components to manipulate a signal in a certain way to improve the final outcome and compensate for unwanted effects of the voicecoil. But the components have unwanted effects themselves. Even wire that hooks the speaker to the amp has unwanted effects, it's why people will spend thousands of dollars for exotic speaker cable. If a driver is well behaved enough that you can eliminate crossover components, it's a good thing.
 
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Not necessarily. A speaker is a mechanical linear system just as a crossover filter is an electrical linear system, only the speaker has issues greater than the issues that a filter might have.

Once the cone is comparable to a wavelength new issues appear that cannot be compensated for which are better filtered out.
 
About "robbing micro-detail" argument...looks inside you're amp ! It's yet full of those bad passive component. Even so really high fidelity speaker got inductance/resistor/capacitors...
About phase shift, simulators allows to build passive network that can correct phase problem.

It's a matter of compromises. I'm not saying crossovers are automatically evil. I just prefer simplicity when possible. Also saying that adding "bad passive components" is ok because there is already "bad passive components" in the audio chain is kind of lame. We may or may not detect the difference depending on the situation but every little difference in keeping the audio signal clean can help.

If you want a midrange/or woofer that can cross easily with higher way, you'll probably search for a beautiful natural high freq roll off...that is in fact due to high inductance of big voicoil, with probably no demodulation ring/nor neodinium motor, that is moreover often masking some cone resonnance (easy to see in distortion plot). But a non linear inductance since voicecoil is moving, that moreover since it has low pass effect, has phase shift effect too, but non dynamically linear.

If I understand what you are saying, you are suggesting that (midrange/woofer) with an advanced motor system with very low inductance and lowpass filter (with a good inductor) is superior to a cheaper high inductance (midrange/woofer) with no filter that is allowed to rolloff naturally because of non-linear effects of voicecoil inductance that varies with things like temperature? I can't argue with that general concept in theory. But I would say it depends on a case by case situation. Also remember that it's not just voicecoil inductance that contributes to woofer rolloff in the high range but also mass. You can theoretically have a quality motor with low inductance that also has smooth rolloff in the highs. It's just rare because of cone breakup issues.
 
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