Perplexed on how single driver speakers can cover such a large Hz range

Let's pretend the cone has to play 2 tones, for example, 100 Hz and 3000Hz, simultaneously.  Imagine looking at the speaker cone in slow-motion.  As it is progressing through its' 100Hz cycles, the cone is also moving, (vibrating), just ever so slightly, at 3000Hz, at the same time.  

That's super-basic explanation, but hopefully it helps.

Here's a little video that may help, as well:

https://www.youtube.com/watch?v=077zpf8gI9E  (FFwd to 4:30 mark)

I just received the Music Direct mailer, where they showcase such a speaker. I don’t remember the details because I had to swat a fly and the mailer went in the trash. In ancient times I put together a five driver per side speakers with some exotic British “full range” long throw metal drivers that were about 21/2” in diameter. I used a high order active crossover to subs. Very efficient and driven by 10 watt per channel SE 300b amps. Everything was analog in those days and the musicality and imaging was really nice on a budget. Think of bobbing up and down on the ocean while rapidly splashing. The short wavelength simply ride on, or modulate the longer wavelengths.  Like all designs there are obvious pitfalls to this approach.  I’ll have to take a look at that MD speaker online.

EVERY speaker design has to compromise somewhere, and this is certainly no exception. In forgoing multiple drivers and crossovers the single driver will have limitations/distortions — it’s just physics.  But, any skillful designer can effectively minimize the compromises while maximizing the benefits of the design.  Such is the art of speaker design. 

@marshinski15

The simple fact is no ’full range’ driver is really full range. Most struggle to get below 50Hz in an optimal enclosure. So if you want full range you will need a subwoofer.

They also are beamy on top. So only one person can sit in the sweet spot and if you want to hear everything you have to keep your head pretty still. For that reason a tweeter is nice, perhaps rear-firing, to at least correct tonal balance if you are off-axis. Nicer if forward firing with the main driver so you get better dispersion.

If there is bass excursion on the driver you get something called ’Doppler Effect distortion’ because a bass note causes the cone to move relatively slowly while much higher tones are also being produced. Those higher tones will be varying in frequency up and down as the bass notes move the cone back and forth.

This causes the presentation to sound congested.

To solve this you don’t play the speaker very loud or don’t play complex material with bass.

If you can get the bass off of the cone it will sound better immediately. So you can see that you need a crossover to keep bass out of it and something for the tweeter as well.

Put simply its best to think of them as ’extended range’ drivers at best. If the speaker is lacking a crossover you know its compromised. I know a lot of single-ended advocates will not like what I’m saying here. But I’ve had a lot of experience with these drivers over the last 20 years. The lack of a crossover is worse for the speaker than a properly designed crossover.

If you use subs, they should not be active over about 80Hz else they will attract attention to themselves so you really only need to go down to 60Hz or so and you can get a good blend. But you have to sort out how to prevent excursion due to bass notes! The lower you allow the driver to go the harder this gets.

IMO if you want full range, you start with a 15" driver of some kind that allows you the bottom octaves and cross over at 400-500Hz to your extended range driver and then roll in the tweeter at about 7-8KHz.

Here ya go!

https://www.youtube.com/watch?v=mjQeoFTqggE

Another review!

https://www.youtube.com/watch?v=_SklRKK18s4

Look up woofer assisted wide band speakers for a cool take on this issue.

I am having a pair of Omega Super Alnico Monitors built right now.  Should have them soon.   Will be using either a REL r305 or Velodyne DD 10 with them ,not sure yet. 

Consider headphones. If the required output is small you can reproduce any frequency

They can’t , I have owned a bunch of these full range drivers, which they are not, and are not linear they may get high frequencies to 16 khz  if a electric field coil driver much much better ,but still need a powered sub to be a full range speaker. And with single drivers non field coil they cannot play with higher SPL levels at all they become peaky in the upper midrange ,included several mentioned which I owned,but will not disparage them ,and start distorting at around 90 db they can sound pleasant but still no bass to 40hz 

a big Electrostatic speaker like Sound Labs is the-only exception stretching the term single driver ,and needs lots of Power to play loud and they are Big speakers but sound great.
 

Then you have transmission line cabinets with single drivers that can go low. Sibelius is one such speaker. But yeah, it isn't for playing crazy loud. All speaker designs are compromises.  I can't remember but Zu or Tekton have a two-driver speaker where the crossover is a very high 12KHz to the tweeter. So the woofer/mid is really doing about 95% of the work and most people on the high side of 60 probably can't even hear the tweeter much anyway. 

An interesting oldie from the 70s was the Rectilinear X(ten) 3 way but the mid range ran from 200 Hz to 8 kHz with a 2 " cone tweeter above that and a 10" woofer in a closed box below so an almost full range speaker. And interestingly the crossover was a series one not a conventional parallel design.

But I agree with lots of us that full range has too many compromises in cut off lows and highs and inability to play loud. But I do love the top to bottom integration. You sense there is no crossover.

Just a closing thought. Perhaps the best full range speakers are a few one way planars and electrostatics. The most wonderful being perhaps the Quad 63 which even could image. 

The old constraints described above for crossoverless single-driver speakers have  been nearly, if not totally, eliminated:

https://www.cubeaudio.eu/reviews

+1 about electrostatics. But even though my Sound Labs get down to 30Hz, they can’t play those lower frequencies at a decent volume, so I added a subwoofer. 
 

To OPs question, think of the surface of a pond that can have different sized waves crossing at the same time from different directions. Your speaker cone is like the pond, vibrating lower frequency waves and high frequency waves all at the same time. The speaker can do that. That’s what music is. As others have pointed out, the quality/accuracy of the sound reproduced by a single cone driver is debatable. 

Speakers don't exactly create different frequencies and then put them together. The single signal is a complex combination created by a signal composed of all the frequencies a microphone picks up. The signal is a complex of hills and valleys one after the other all combined into one ever changing signal.

Where you really want one driver to be reproducing all frequencies is in the heart of the music---the midrange. The Eminent Technology LFT magnetic-planar driver reproduces 180Hz to 10kHz, with no crossover in that range! In the LFT-8b an 8" dynamic driver in a sealed enclosure does 180Hz down, a ribbon tweeter 10kHz up.

My 2 cents:

- Most speakers under $2k have junk crossovers, resonant cabinets and mismatched drivers. You're losing a lot of detail in the midrange and you don't even know it. It's only clear after you listen to a decent pair of single driver speakers. 

- Most speakers with the exception of true "full-range" towers don't extend past 50Hz. So the whole "fullrange drivers can't do bass" argument is so ignorant to the fact that most speakers use midrange drivers for bass. Most speakers benefit from a sub. Nobody is going to convince me that Harbeth P3SR or KEF LS50 have deep bass. 

- If you live in a reasonably sized flat you're not going to push the volume to night club levels. My guests often complained that the music was too loud on my small single driver speakers. But the same could be said about a large Bluetooth speaker. How much volume do you need? 

These factors have convinced me to buy the Closer Acoustics OGY blind and I have no regrets. Just find me a better (new) speaker under $2k. The midrange, treble and imaging is step up from the KEF LS50 Meta. The bass is fast and punchy thanks to the transmission line. But don't expect deep full-bodied bass. You can get that from a subwoofer. 

I'm also surprised by the enthusiasm surrounding coaxial drivers which exhibit a lot of the same problems as single driver speakers: doppler effect, weaker bass due to smaller speaker excursion (the woofer cone acts as a horn, a moving horn is problematic). And on top of that, coaxial drivers have crossovers and the multiple drivers aren't moving at the same speed causing a time delay. 

+1 as usual to Atmasphere for an eloquent explanation.

@kokakolia, with respect, I think you are conflating/confusing perceived loudness and frequency range. A speaker with limited frequency range will often be perceived to be louder than a full range speaker especially if it's frequency response is ragged. A downside of speakers with limited bass response is that they are often driven harder in an attempt to get some bass impact, which then results in them being played too loud and showing up deficiencies elsewhere in the speaker.

It is the reason why the best headphone and the only one i like is a Hybrid with a dynamic cell specialized in bass and a electrostatic cell specialized in higher frequencies over 4,000 hertz the cross over slowly decreasing point for the two cells..And a grid of Helmholtz tuned resonators inside to clean bass and mid bass... it work so much well that none of my past 9 headphones compared one second to the K340... All are under my bed for eternity or for computer use... 😊

The AKG K340 can make a soundfield more defined and clearer than my speakers because of what atmasphere explained so well...

My room dedicated acoustic so well it was tuned , was limited by my Mission Cyrus speakers under 50 hertz...And their tweeter limitation and roll off..

When i lost my dedicated room i was sad... When i optimized this headphone i enter in sonic heaven anew but with no more too much acoustic limitations... A well optimized modified AKG K340 rival any headphone today... It is the only successful  hybrid headphone where one of the cell is not only a super tweeter as the dharma was..

Any designer in audio is an artist not only a scientist... because he must work and jugg with many trade-off at the same times... The designers who are not artist are not the great one , they apply a recipe...

As dynamiclinearity mentioned, at any given, whatever any driver is doing at any given time is a complex combination of many different frequencies albeit in a more limited way in a classic woofer, midrange or tweeter than a single driver design. It’s always amazing to me that this can occur & sound realistic. 
 

Even more amazing to me is that a single stylus in a phono cartridge can somehow do a similar but inverse thing &  react to the full range squiggles in a spinning vinyl disc & do so accurately!  Also similarly but not always true, the better cartridges can’t “ play loudly” either & general their outputs  are very low & require substantial amplification to be “heard”.  Thomas Edison was one smart dude!! 

@dlcockrum 

How?

@kokakolia 

You are obviously comparing single driver speakers to lower end multi driver speakers. Do you feel the same when comparing them to higher end speakers ?

I've heard a few systems with a single driver where I thought the sound was quite good, overall, and particularly good in certain aspects.  The single driver systems I liked were the Charney Audio Companion (particularly with the AER driver) and the Voxativ Ampeggio and Songer Audio S1.  Most of the others I heard had too rough and peaky upper midrange colorations; I did not mind as much the lack of really deep bass.  I agree with those above who say that using the full-range driver as a wide range driver in a multi-way system is a better application of such drivers. With the right wide-range driver, the crossover points can be set low enough and high enough to be out of the range where the ear is most sensitive to crossover anomalies.  Also, wide range drivers allow for the use of simpler crossovers with shallower slopes.

I've heard a number of successful custom builds using such drivers in multi-way system.  Many are custom-built systems using some fairly exotic Western Electric and Jensen drivers (like the field coil M 10 and M 18 drivers).  Among successful modern multi-ways are the two-way are the Cube Audio Nenuphar Basis (to me, MUCH better than their single driver systems), and the Songer Audio S2.  I've heard really nice horn-based systems where gigantic horns were used to allow a very low crossover such that the compression midrange was crossed over to the bass driver at 150 hz and the crossover to the tweeter was around 8,000 hz.  Even the best of these systems have compromises, of course, mostly in that they don't go extremely deep.  But, the speed, purity, liveliness and vivid quality of wide-range drivers used correctly makes such compromises worthwhile.

And there is that little thing called MASS and the other one ACCELERATION (btw, they don't like each other much). So yeah, and can CLEARLY feel the OP. Imagine the force needed to shake that massive cone 10,000 times per second back and forth. Obviously, something has to give. 

I’m a longstanding fan of single driver speakers. My main speakers are an upgraded pair of Voxativ speakers, i.e., their driver was upgraded to a more power magnet and a custom horn created that was tuned for upper mids. I’ve come to experience that the cabinet design greatly influences the depth for the lower frequencies. Single driver speakers are thin on deep bass, but I love their speed. The preferred dynamic range was achieved only with the inclusion of a pair of subs inserted into the 2 channel system. BTW, Voxativ now has single driver models with with built in subs. 

Also have to mention  the Walsh driver solution to  keeping the sound coherent across the hz specturm.    Their composite cone is inverted in the cabinet and the sounds rolls off the back of the cone in a 360 degree fashion (they attenuate the back of the speaker sound via sound absorber for better imaging)  .  As the signal from the voice coil travels down the speaker all of the individual hz responses are reproduced and come off the cone in parallel so that the result is a completely coherent line source for the sound (CLS) .    Another advantage of this solution is  a very large sweet spot in the room .  

@ronboco See video linked below starting at 6:30 where Jon Ver Halen, Cube Audio’s US distributor, explains the unique engineering solutions incorporated into their Nenuphar loudspeakers to overcome the frequency extreme limitations of traditional single driver designs of the past as well as several other improved aspects of their design:

https://www.youtube.com/watch?v=Ma7dvPyr5T0&t=1s

My brain hertz just thinking about it.

The old constraints described above for crossoverless single-driver speakers have  been nearly, if not totally, eliminated:

@dlcockrum This statement is false. I explained why in my prior post.

@ronboco Yes, I am very much a budget-conscious consumer. I watch a lot of reviews and GR Research stood out to me. There was something appalling about seeing cheap crossover parts, drivers and flimsy cabinets on major brand speakers, some of which costed thousands. I was still rocking the Klipsch RP600M which I loathed since day 1 (They suck). So yeah, I figured that I’d look into single driver speakers with sturdy cabinets and no crossover to muck things up. At least most of the money will go into the drivers and the cabinet. 
 

I visited a shop in Paris which sells a bunch of single driver speakers (unbranded DIY kits) alongside Atohm and Davis Acoustics speakers. The speakers based on the Audax AM21 driver were brilliant. I gotta say that the Atohm and Davis Acoustics speakers sounded veiled next to the Audax AM21 which were just faster and more immersive. I didn’t get the AM21 since they were a bit too large for my tiny living room. 

Years later I experienced a few other speakers with multiple drivers and they were just great. I could happily live with the KEF LS60 but the price is eye-watering and they exhibit an overly “clean Hi-Fi” sound at times. At the very high end you get to have a larger sense of scale/depth/volume and way better bass. But I personally don’t feel like my single driver speakers are bested in the midrange/treble/detail categories. 
 

You could assume that my hearing isn’t great, and that wouldn’t be far fetched. So my end game setup is very attainable. I’d like to be the village idiot in that conversation, or the average person at the very least. 

@atmasphere My ears say otherwise, but they can’t read. 

paradisecom, Thanks for your input. You cleared up my perplexed mind.

My ears say otherwise, but they can’t read.

@dlcockrum You might want to go some place where you can hear other speakers. As I pointed out earlier, it makes a big difference what sort of music you play. Any ’full range’ speaker will fall flat on its face playing a lot of the music I like to play, even if not played all that loudly. This track has a fair amount of bass in the opening section:

https://www.youtube.com/watch?v=ckM_TklU_AQ

Your speakers won’t even acknowledge that the bass notes are there. But those bass notes will cause the speaker to make distortion and sound congested. This track isn’t congested.

FWIW the speakers I’m playing are the Classic Audio Loudspeakers model T3.3, which is a bass reflex speaker flat to 20Hz employing 15" field coil woofers and field coil horns. I play bass and did so in a variety of orchestras so I expect the bass to be right otherwise I’m not convinced.

At any rate if you don’t play tracks with bass or simply don’t like bass, you might consider a filter in your system to block bass from getting to your amps and speakers- you may find they sound better as a result.

It is quite simple however it is also difficult to implement. You also need to consider what is "Full Range". Very very few speakers reach into sub bass territory yet most people consider most box speakers full range. Most speakers reach into the 40-50hz flat region and that can be accomplished via rear horn with a good AER, Voxativ, Lowther or even a Lii Audio but I am only a fan of Lowther if rebuilt by one of the gurus or the Field coil version. 

You need 2 things to effectively pull it off and it leads to a driver that needs to be implemented in a very specific manner. I am a member of the "Lowther Modification" group on Fb where several of us , myself included make our own high eff drivers completely from scratch so I know these driver types intimately. 

I also own AER BD3 drivers in addition to the ones I build and 5 other FR drivers and there is a definite trend in all of them. 

In order to reach the very high frequencies in a large driver you need a VERY strong motor and a VERY light cone. The cones in these have employed long fibers, stiffening ribs and rolled edges for quite some time and those features are just now becoming standard in ScanSpeak, Eton and others as they play catchup.

The strong motor, light cone formula leads to a rising frequency response with a VERY low eletrical Q  that is best used in a back or front loaded horn. The rear horn will give the best low frequency response from a driver that barely needs to move to make bass. As the motor strength decreases so does the HF extension.

If they are not in a rear horn then bass response will suffer along with efficiency. 

The really good drivers are not cheap and should not be confused with the cheap kit drivers. The real good drivers start at $10,000 a pair and that is just the driver.

While back loaded horns and "full range" speakers of this type are not as popular in the US there is a new US manufacturer, Songer Audio, that makes an outstanding field coil "full range" speaker w open baffle and integrated sub that I heard 3 weeks ago in the LA show that is incredible. 

I think you can get full-range drivers to play some good bass, in-room.  But the cost would be cabinet size.  You can take a larger 10"-15" full-range driver, but with their reduced xmax, they need a big enclosure to reach into the lower frequencies.  Something like 8, 12 or more cubic feet in size to get the appropriate bass output, which most people can't or don't want to sacrifice.

marshinski15

You have some great help here from the replies.  I will will give you my take.

First up, in the normal run of things you would like to have a full range of frequency response.  But (1) the midrange is where most of the music is; (2) The avoidance of crossovers is a benefit - but this is (a) mitigated by quality (whatever that is) designs of the crossover and (2) systems (eg  ATC) where all three drivers in a three way system have similar cone designs.  (3) And this is my main point: it depends on your music.  Say your real interest is in string quartets: then the benefits of a single driver come to the fore.  Disclosure: I have not heard a single driver system. 

They play into break-up modes, that’s how. 

If you get a chance, give a listen to the Manger speakers. The Manger MST covers a large part of the frequency range, assisted by one or two 8” woofers.  Different technology altogether and extremely well executed.  Active or passive models in modest but elegant enclosures.  Nothing else like them on the market in many respects.  

@andrei_nz I hope you could listen to single driver speakers someday. Yes, string instruments (especially guitars) sound way better on single driver speakers. Vocals sound more clear and natural too. This sealed the deal for me as I listen to a a lot of folk/country music.