View Full Version : When and why did the typical floorstanding speaker lose the midrange driver?
Ollie Valcairo
13-02-2020, 09:25
Up to the 1990s, and maybe later too, when you bought a floorstanding speaker cabinet there most likely be a tweeter, a midrange, and a bass driver. Now you will typically get a tweeter and two identical lower frequency drivers. Why did that happen and over what period did the switch occur? I suppose there was technological improvement that meant a 160mm driver could now handle midrange and bass sounds with good balance, and that was not possible earlier.
Now, when I write 'typical', I mean most floorstanding speakers costing up to £1000 roughly. I know there are many setups that employ 3 different drivers but I don't think these are typical any longer.
Any designer makes decisions on many factors; his and others' sensibilities to speakers' failings, cost/benefit analysis of various options, current fashion, change in technology which may eliminate previous shortcomings, are a few.
This applies to bass types, and what you describe. Mid/woofers may now be designed to go higher with a better performance thus negating the need for another driver and a much more difficult to design and expensive to make Xover.
It is also necessary to look at what the current 'fad' is, and to perhaps follow it to get a share of the market.
I don't like three ways because of the several points of source, but others may be more offended by the other, two way design compromises.
There are very few ABRs now, or transmission lines, when nonce they were much more frequently produced.
Often a mid/bass driver is now used only for its upper range presumably for the economic reasons of only needing to produce two driver types.
Up to the 1990s, and maybe later too, when you bought a floorstanding speaker cabinet there most likely be a tweeter, a midrange, and a bass driver. Now you will typically get a tweeter and two identical lower frequency drivers. Why did that happen and over what period did the switch occur? I suppose there was technological improvement that meant a 160mm driver could now handle midrange and bass sounds with good balance, and that was not possible earlier.
Pretty much what you say, drivers improved, I'd say it started really catching on in the late 1980s though. Before that it would be a two way with an ABR to reinforce the bass.
If you look at model ranges from the big companies they tend to go two-way at the bottom, then a two and half way, but the flagship of the range will still be a three or four way design.
Lawrence001
14-02-2020, 11:00
The fashion for slimmer speakers probably had an effect as well. As makers started adding multiple 5-6" drivers they would naturally go higher than an 8-12" driver. Combined with the "invention" of (or common usage of, as I don't know when the idea was first thought up) the 2.5 way crossover, this made separate mid range drivers redundant. It was probably cheaper to make or buy more of the same size driver too (although the better 2.5 way speakers will have different spec drivers for mid/bass and bass).
hifi_dave
14-02-2020, 11:52
It’s not really that drive units improved, because they didn’t particularly. What really changed was the that customers became less willing to buy large, wide baffled, speakers. Previously the typical three way speaker would have a 10 or 12” bass driver and this would result in a large and imposing front face. The emerging fashion for slimmer speakers is what really dictated the move to multiple smaller drivers.
Exactly.
Fashion drives many speaker brands. The modern speaker needs to be as small and slim as possible, even if the performance suffers.
RobbieGong
14-02-2020, 19:13
Exactly.
Fashion drives many speaker brands. The modern speaker needs to be as small and slim as possible, even if the performance suffers.
Personally I'm glad speaker design moved to offering up slimmer, home friendly cabinets and drivers. Most speaker builders / designers still do the big boxes, ie 10 inch / 12 inch driver designs.
In my experience slim doesnt always mean performance suffers - by that I'm assuming you're making reference to the way big bass woofers can move air and go really deep and low in a way very small drivers cant.
In my experience, the genuinely good slimmer speaker designs can give you a tight, deep bass that if there can be solid, firm, tight tuneful and natural, which is exactly what my Spendor D7's do. Add to that accurate as in if it's there you'll most certainly get it and feel it, as opposed to merely big, full, large bass woofer weightiness.
In the real world of of small / medium lounge, I can certainly say there is no sense of anything missing. Bigger, larger lounge and there are more than enough 'slimmer box' designs that will give more than enough good deep bass - Spendor D9 for instance.
Pretty much like F1 which went from Big 3.5 V8 engines to 1.6 hybrids which are if anything even faster.
Great, intelligent, quality design will often achieve the objective in my experience, thank God for progress and alternative options.
Made in 1968
14-02-2020, 19:20
A lot of people live in small Lego houses these days, Well have done for years but lots of New Builds. If you ever been in one the rooms are as big as a prison Cell so i think small Floor standers are popular & bigger ones are a not. I do see a lot of people wanting tiny Bookshelf speakers too. Not sure if the industry sees this but i do see a lot of small floor standers available. We are in a 4.6mtr square Living Room, may seem big but when the sofa & furniture are in i only have room for Tiny speakers..
RobbieGong
14-02-2020, 20:07
Sorry, I'm meaning most or a lot do the slim designs as well as large speaker designs with big woofers, so Spendor, Tannoy, Usher, Wilson Benesh, ATC, Klipsch .......
Made in 1968
14-02-2020, 21:05
What the Average height of a modern Floorstander 1Mtr Tall?
I personally hate the way that smallish mid range drivers are forced to cover the lower frequencies. Nothing worse than seeing such drivers flapping in the breeze trying to deliver.
Part of this may be due to the fact that infra-base no longer seems to be popular or fashionable. You cannot get acceptable coverage down to 15 Hz with these modern devices.
Part of this may be due to the fact that infra-base no longer seems to be popular or fashionable. You cannot get acceptable coverage down to 15 Hz with these modern devices.
I seriously doubt you can get 'acceptable coverage down to 15Hz' with any reasonably sized domestic speaker. Most of what you are hearing is usually frequency doubling.
Lawrence001
29-02-2020, 23:36
I seriously doubt you can get 'acceptable coverage down to 15Hz' with any reasonably sized domestic speaker. Most of what you are hearing is usually frequency doubling.Can domestic rooms even handle the note, what's the wavelength?
Can domestic rooms even handle the note, what's the wavelength?
You can certainly reproduce a note whose wavelength is greater than the maximum dimensions of the room - its just that its not a free-space situation. Also the sensitivity of the human ear is very low at those frequencies, so taken with the need to provide a compression wave, and the generally poor efficiency of speakers, an awful lot of power is required.
I can assure you that it is possible to reproduce audio adequately down to 15 Hz. I have designed speaker instruments which do it perfectly (- 3dB of course). (I am an indentured apprenticeship-served Engineer with a PhD in Electronic Engineering.) The problem is that the physical enclosures are large, and that is the difficulty for most domestic situations in today's modern miniature houses for dwarfs. However, if you have a large enough home that is not a great problem. (It is always the wife which is biggest problem.) The lowest note on a good pipe organ is a 32 foot open pipe and is a C (15 Hz). Real Hi-Fi is all about reproducing the total audio spectrum properly.
I can assure you that it is possible to reproduce audio adequately down to 15 Hz. I have designed speaker instruments which do it perfectly (- 3dB of course). (I am an indentured apprenticeship-served Engineer with a PhD in Electronic Engineering.) The problem is that the physical enclosures are large, and that is the difficulty for most domestic situations in today's modern miniature houses for dwarfs. However, if you have a large enough home that is not a great problem. (It is always the wife which is biggest problem.) The lowest note on a good pipe organ is a 32 foot open pipe and is a C (15 Hz). Real Hi-Fi is all about reproducing the total audio spectrum properly.
I think the point was not that you can't get speakers to do useful 15Hz reproduction, but that hardly any speakers do either currently or from way back when, midrange driver or not.
Indeed Macca; that was the main reason I was driven to designing and making my own. But as you seem to agree, it can be done. The large size necessary is the limitation. But of course that is why a double bass is so large.
By the way, one of the best ways to extend infra bass is to install the baffle assembly in an outside wall of the room where you wish to listen, with a suitable vent to the outside environment. You must of course protect from inclement weather. This approach produces much superior results to Helmholtz resonating enclosures (reflex enclosures) and labyrinths as the anti-phase problem is completely eliminated, and there is no back pressure whatsoever on the drive units.
Taking things to extremes me thinks
Indeed Macca; that was the main reason I was driven to designing and making my own. But as you seem to agree, it can be done. The large size necessary is the limitation. But of course that is why a double bass is so large.
By the way, one of the best ways to extend infra bass is to install the baffle assembly in an outside wall of the room where you wish to listen, with a suitable vent to the outside environment. You must of course protect from inclement weather. This approach produces much superior results to Helmholtz resonating enclosures (reflex enclosures) and labyrinths as the anti-phase problem is completely eliminated, and there is no back pressure whatsoever on the drive units.
That was what I had in mind when I said it could be done, but not in a free space environment. Brüel & Kjær wrote a paper on such a compression wave approach a few years ago. You still need a lot of power though.
Indeed Macca; that was the main reason I was driven to designing and making my own. But as you seem to agree, it can be done. The large size necessary is the limitation. But of course that is why a double bass is so large.
By the way, one of the best ways to extend infra bass is to install the baffle assembly in an outside wall of the room where you wish to listen, with a suitable vent to the outside environment. You must of course protect from inclement weather. This approach produces much superior results to Helmholtz resonating enclosures (reflex enclosures) and labyrinths as the anti-phase problem is completely eliminated, and there is no back pressure whatsoever on the drive units.
I'd be lying if I said I hadn't considered it. More than once. I think it was Paul Messenger did do it with 15'' Tannoys but his only vented to the adjoining room. Probably sufficient though.
Please forgive me if I am wrong, I do not even have a degree, let alone a PhD, but even the external environment method cannot completely decouple the back emitted wave because the all of the factors are finite.
With enough resources and an acceptance domestically, couldn't we go down to 2Hz?
The idea of an externally mounted speaker in the wall to produce a low frequency compression wave ideally requires the listening environment to be a sealed volume, which of course it is not.
Even so, low frequency waves can be generated by such means. However to have a palpable presence (infra bass is felt and not heard), a considerable amount of power is still required.
I think most of us have considered it more than once. The principle, provided a true outside wall is selected, (without it having any windows) is really one of the ultimate infinite baffle.
Pharos: I do not think there would be any point in going down to 2 Hz. Even 16 Hz. is not really a discernible note, but it gives presence. Provided the external wall selected does not have any windows and is a modern double cavity wall, there is no back pressure on the drive units and any "back wave" is radiated externally into the environment. It is thus the nearest thing to a perfect infinite baffle.
G. A Briggs at Wharfedale got close to it with his brick corner reflex, but although it produced infra-bass amazingly it did still suffer from the the anti-phase problem, because it was a Helmholtz resonator. Nevertheless it reduced the cone resonance to 18 Hz and produced this frequency adequately with only two watts of power I believe.
There's a handful of pipe organs in the world that have an 8Hz pipe.
There is one in the old Atlantic City Hall. Apparently the 8Hz pipe in action sounds and feels very much like a large helicopter is hovering right over the building.
Ran my Castle Howards in the back yard at a family gathering and the SQ was the best I have heard from them, they are a 2.5 way 1/4 wave design, one of the drivers is upward facing on the top of the cabinet.
Small drivers can work well, I have tried other speakers, but keep coming back to the 1995 S1 Howards.
There's a handful of pipe organs in the world that have an 8Hz pipe.
There is one in the old Atlantic City Hall. Apparently the 8Hz pipe in action sounds and feels very much like a large helicopter is hovering right over the building.
That's very close to the alpha rhythm frequency of the human brain. Long term exposure to such an external stimulii can cause epileptic fits (in the case of light pulsing at that frequency) and if loud enough can cause loss of bodily control (I'll leave you to imagine what that means). There is a phenomenon known as 'sick building syndrome', wherein occupants (these 'sick' buildings are usually offices) reported feeling unwell after a day's work there. The cause was often traced to air-conditioning units generating low level, low frequency sound.
Many years ago the French looked into the use of infrasound for crowd control. The researchers would have to wear thick protective clothing, making them look like Michelin 'tyre men'. But the project was abandoned because the massive horn speakers used were just too unwieldly for practical use.
Lawrence001
03-03-2020, 21:37
I think most of us have considered it more than once. The principle, provided a true outside wall is selected, (without it having any windows) is really one of the ultimate infinite baffle.I'm not sure most forum members have considered mounting their speakers to the external wall venting to the outside. Happy to be corrected though. Maybe we need a vote [emoji38]
I have never considered it - I'm just aware that some enthusiasts have done so (usually horn loaded speakers, opening into the listening room).
Pharos: I do not think there would be any point in going down to 2 Hz. Even 16 Hz. is not really a discernible note, but it gives presence. Provided the external wall selected does not have any windows and is a modern double cavity wall, there is no back pressure on the drive units and any "back wave" is radiated externally into the environment. It is thus the nearest thing to a perfect infinite baffle.
G. A Briggs at Wharfedale got close to it with his brick corner reflex, but although it produced infra-bass amazingly it did still suffer from the the anti-phase problem, because it was a Helmholtz resonator. Nevertheless it reduced the cone resonance to 18 Hz and produced this frequency adequately with only two watts of power I believe.
" I do not think there would be any point in going down to 2 Hz", is a value judgement.
"Provided the external wall selected does not have any windows and is a modern double cavity wall, there is no back pressure on the drive units ".
Surely the cavity is finite, and will provide some back pressure, and the cavity volume is also finite.
I think you are missing the philosophical point that there will always be some back pressure, even if it is 10^1000 dB down. World is finite, and hence back pressure can never equal zero.
Similarly, I am sure that the ear does have some sensitivity at 2Hz, and for similar reasons, and it may well be also 10^100dB down, and may provide what you describe as presence.
OK: perhaps only a few of us have ever considered it or actually done it.
OK it is a value judgement; but I don't think most people would want to extend to the extreme of 2 Hz, even if it were practical to do so.
You seem to miss the issue of proper sealing. Whether in a cavity wall or not proper air-tight sealing is necessary between the baffle board and inner and outer layers, and the drive units must not vent into the wall cavity. They must be able to vent into the outside atmosphere only. It is a type of installation only appropriate for larger rooms (not thus for the modern dwarf houses). Provided any windows are properly sealed and that the room is sufficiently large the issues you cite are so small as to be insignificant. As with all things H-Fi (and food) the proof of the pudding is in the eating. If you had heard a properly-executed example of this type of installation you would understand just how good it can be, using the best available LF drive units.
I agree about 2Hz.
It wasn't apparent to me whether or not you were referring to using the cavity as an enclosure.
If the rear of the driver is exposed (right through the cavity) tyo the external environment that opens up a whole new can of worms.
I also agree about the other issues at least tending towards insignificance.
I believe the switch to two drivers was started by the introdoction of ports to the cabinet.
This meant a driver could reproduce the mids and then resonate with the port for the lower frequencies.
Two drivers equals lower cost.
This was a follow-on from the ABR type of enclosure where they used a speaker less voice coil etc to act as a damped port.
graham67
05-03-2020, 21:16
Pretty much like F1 which went from Big 3.5 V8 engines to 1.6 hybrids which are if anything even faster.
Hi Robbie, at the risk of mangling my metaphors, modern F1 cars better the old ones in most objective areas. However, most fans would consider that the big old V8 bangers sound much better and elicit an emotional reaction that eludes the current crop 😉.
But i agree, it is good to have a choice as not everyone wants to live in a recording studio. ☺
Ronald,
How much output (in Phons) at 15Hz did your designs generate and how much electrical power is required?
Ronald,
How much output (in Phons) at 15Hz did your designs generate and how much electrical power is required?
Hi Barry, I used around a normal maximum of 40 W rms per channel (from an 80 W rms per channel amplifier), producing an output at 20 Hz of around 100 Phons. You will gather that I like my music rather LOUD (much to my wife's displeasure). But that is mainly to cover the large dynamic range particularly of the Romantic period classical music which I enjoy the most, like Mahler; it is only on peak volume passages with much bass content that the music is this loud. I try to reproduce music at the same level and with the same dynamic range which it had originally. I admit that you do really need a relatively large detached house to do this. In modern dwarf houses, all crammed in too close to one another and with cupboards instead of rooms, it is quite inappropriate. Also with the dumb announcers on radio these days who get right up close to a relatively wide-range microphone and thus produce a distorted excessive bass timbre to their voice, that can be a continuous problem.
As I observed earlier G A Briggs of Wharfedale with his corner brick reflex, which had a vent size of 9 inches X 6 inches and a 15 inch diameter bass driver was able to lower the cone resonance down to 18 Hz. That was pretty good and he claimed that at 18 Hz with only 2 W rms drive into the unit a lighted match was extinguished at the vent. I also designed two modified reflex cabinets with more modern drive units and they were excellent and achieved better than this down to 16 Hz. (I prefer KEF drive units and still have several new vintage ones never used in their original packing, left over from when I was experimenting and building enclosures. I am now getting rather too old now for that sort of thing!!) The problem of course was the size of these units. Eventually my wife insisted that I demolish them, sadly. I now have to make do with much smaller units, which I also built, and the infra-base performance of these is of course not as good, but still better than most modern commercially-available units. (I am hoping soon to build some new units to a later design which I had configured, and never yet built, because I have a house in another European country with a large basement, which thus has lots of available room, so that the wife cannot complain so much! She probably will though!)
100 Phon is about 27dB above the threshold of hearing at 20Hz. I'm surprised it only requires 40W to achieve that volume level.
How big is your listening room? Mine is 75m3, so I calculate that for adiabatic expansion/compression to achieve the above pressure level change, the 'speaker' would have to move about 1m3 of air during each half cycle. I don't understand how that can be done with drivers of modest size.
From drrdf;
"Also with the dumb announcers on radio these days who get right up close to a relatively wide-range microphone and thus produce a distorted excessive bass timbre to their voice, that can be a continuous problem."
The major factors which to me make radio virtually unlistenable are; 1 firstly, as you state, 2 the inane rubbish being spoken, and 3 the poor articulation/enunciation, the latter of course serving to obscure the second one; if rubbish is spoken well, it readily exposes itself for what it is.
I believe the switch to two drivers was started by the introdoction of ports to the cabinet.
This meant a driver could reproduce the mids and then resonate with the port for the lower frequencies.
Two drivers equals lower cost.
This was a follow-on from the ABR type of enclosure where they used a speaker less voice coil etc to act as a damped port.
Unless I have it all wrong, the internal space in the cabinet is a Helmholtz resonator. any bass that is allowed out is essentially a one note honk. Deep and supportive of the mid band but not very musical.
That raises the question of the Q of that resonance - breadth of the curve.
Barry: More than one KEF bass driver was used in each unit, and as I explained that was only the peak level, to cover a wide dynamic range, and 40 W was an average level with the full 80 W available on the highest peaks. Who suggested that any of this was of modest size? I have made the point that all of this sort of approach is very volume consuming. You are also it seems ignoring the example which I cited where Briggs accomplished a significant radiation at 18 Hz with only 2 W of power output to a 15 inch acoustic driver. I do not have the house where I installed these infinite baffles any longer; the room where they were installed was around 119 cu m. As I explained I currently have to make do with smaller but nevertheless good units. Clearly they do not produce that performance. The parameters which you seem to concentrate upon to attempt shoot down this approach and its superb infra-bass performance are again in my opinion insignificant to the overall capability. Again I would point out that the proof of the pudding is in the eating. As you indicated previously you have evidently never tried it nor would want to, so you seem to want to denigrate the whole idea. Fair enough if that is what you want to do.
However for all practical purposes I would suggest that a large well-designed bass reflex unit is capable of an adequate performance in the lower bass region, particularly due to the increased Q factor, but does suffer from the anti-phase effect.
Pharos: I agree entirely with all of your points.
Barry: More than one KEF bass driver was used in each unit, and as I explained that was only the peak level, to cover a wide dynamic range, and 40 W was an average level with the full 80 W available on the highest peaks. Who suggested that any of this was of modest size? I have made the point that all of this sort of approach is very volume consuming. You are also it seems ignoring the example which I cited where Briggs accomplished a significant radiation at 18 Hz with only 2 W of power output to a 15 inch acoustic driver. I do not have the house where I installed these infinite baffles any longer; the room where they were installed was around 119 cu m. As I explained I currently have to make do with smaller but nevertheless good units. Clearly they do not produce that performance. The parameters which you seem to concentrate upon to attempt shoot down this approach and its superb infra-bass performance are again in my opinion insignificant to the overall capability. Again I would point out that the proof of the pudding is in the eating. As you indicated previously you have evidently never tried it nor would want to, so you seem to want to denigrate the whole idea. Fair enough if that is what you want to do.
However for all practical purposes I would suggest that a large well-designed bass reflex unit is capable of an adequate performance in the lower bass region, particularly due to the increased Q factor, but does suffer from the anti-phase effect.
I was not denigrating your approach - I was trying to understand it. The calculations I made followed those of Bruel & Kjaer, on the subject of low frequency sound generation in a small volume (small compared to the wavelength).
I was not denigrating your approach - I was trying to understand it. The calculations I made followed those of Bruel & Kjaer, on the subject of low frequency sound generation in a small volume (small compared to the wavelength).
OK Barry, I understand: I think ultimately it is one of those try it and see issues; and due to the resources necessary (mainly house) it is not an option open to all. By the way, I forgot to mention that an approach I have tried previously with some significant success is to vent Bass Reflex enclosures and labyrinth enclosures, where you have a house with a timber floor (increasingly unusual these days with solid floors of course) via an airtight pipe to the underfloor cavity. This means that there is no visible port on the enclosure, and the pipe goes directly from the bottom of the enclosure through the floor into the underfloor cavity. This I have found produces better infra-bass and eliminates to all intents and purposes any anti-phase radiation.
Ronald
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