Floorstanders - 2 way or 3 way ? [Archive]

RobbieGong

29-07-2016, 22:07

I've always loved floor standers and only ever had two ways.
What's the story regarding two way and three way speakers ?

I'm aware that in general terms they say a well implemented three way should be or would be better than a well implemented two way due to the fact the tweeter deals with treble / high frequencies, the mid driver only having to deal with mid range and the bass driver similarly only having the low frequencies to take care of, in theory resulting in better overall separation.
This is opposed to the two way configuration which relies on a tweeter, then just the one driver looking after both mid and bass.
I'm well aware that nothing is perfect though and that there are more than enough very well implemented two ways that are as good or even better than some good three ways.

I'm interested in thoughts and views

struth

29-07-2016, 22:12

I quite like a 2 way with passive bass, as in my Cara's, but I'm mostly into 1 way. 3 way does make xover points more complicated, and very important to get right.

Stratmangler

29-07-2016, 22:19

Who says that a 2 way speaker has only 1 mid/bass driver?
They're talking rubbish if that's what they're saying.

These speakers are 2 way speakers.
These are in their pre veneered raw state.
http://www.audio-talk.co.uk/colin/EDINGDALE09.JPG

RobbieGong

29-07-2016, 22:26

Who says that a 2 way speaker has only 1 mid/bass driver?
They're talking rubbish if that's what they're saying.

These speakers are 2 way speakers
http://www.audio-talk.co.uk/colin/EDINGDALE09.JPG

Cool ya jets Christopher :) No one said anything to me. I was more alluding to two driver / two way, verses three driver / three way configuration but you've taught me something with your multi driver floorstanders - interesting.

walpurgis

29-07-2016, 22:27

This is a two way speaker as well.

http://i65.tinypic.com/i4eahc.jpg

walpurgis

29-07-2016, 22:29

It's rare for a multi way speaker to appeal to me. There have been the odd examples that passed muster, but I generally seem to like two way and one way full range speakers.

Stratmangler

29-07-2016, 22:31

The 2 way bit refers solely to the crossover.
The gang of 4 are wired so that they are as one - it's an old trick, more commonly seen in yer average 4x12 guitar cabinet.

struth

29-07-2016, 22:33

yup. series parallel likely. My twins are in series as they are low ohm speakers. still one way though

walpurgis

29-07-2016, 22:35

I guess these five way Dynaudios might not appeal Robbie.

http://i65.tinypic.com/29on804.jpg

They look all wrong to me, but they have had good reviews.

RobbieGong

29-07-2016, 22:41

I guess these five way Dynaudios might not appeal Robbie.

http://i65.tinypic.com/29on804.jpg

They look all wrong to me, but they have had good reviews.

Too blingy and look like you'd need a very large room indeed.
The only multi driver speakers I ever liked was the Wharfedale E70's and E90's. I was a kid then in the 1970's and they just looked the biz to me at the time.
I'm a lot older and wiser now. Next speakers will likely be Spendor S8e or more likely the S9 (non e) which has somehow caught my eye / radar.

walpurgis

29-07-2016, 22:47

There has been the odd big vintage multi way JBL that I've liked. The Avant Garde Trio with the big bass unit sounds incredibly good (well, it actually just sounds incredible). The old Spendor S100 was very sweet too.

struth

29-07-2016, 22:52

I like the Edingdales. they are I think 3 mid/bass drivers and tweeter, but 2 way. Sound superb with most setups, although I think room needs to be decent sized if your using any power. A bit like mine really,

Macca

29-07-2016, 22:55

I quite like a 2 way with passive bass, as in my Cara's, but I'm mostly into 1 way. 3 way does make xover points more complicated, and very important to get right.

But using a driver just for the mid band means you can put the crossovers at less sensitive positions in the frequency range. Hearing is most sensitive 1-3 KHz which is where your two way usually crosses over. A Tannoy DC is in practice a three-way and the crossover is below 1Khz.

walpurgis

29-07-2016, 22:57

A Tannoy DC is in practice a three-way

:scratch:

struth

29-07-2016, 23:00

I know mine are quite sweet, at there price point martin. Not a huge bass line but I like that. Ive not used them for some time, but dont feel I want to sell, as they are the best set of their type Ive had, at anywhere near pricepoint.

danilo

29-07-2016, 23:02

A Tannoy DC is in practice a three-way and the crossover is below 1Khz.

Late Night? ... perhaps.

Macca

29-07-2016, 23:03

:scratch:

The combination of the horn throat and the inner circumference of the cone effectively makes a mid-range driver. You'd need someone like Paul RFC to explain the exact technicalities.

walpurgis

29-07-2016, 23:07

Sabaselfsit

30-07-2016, 00:12

I am a 3 way fan. But resently had a listen to the Klipsch Reference Premiere RP-280F which is a 2 way construction, and they sounded incredible to my ears. 1 horn and 2 x 8" bass/midrange.

Not many hi-fi manufacturers use such large woofers to also play the midrange as it may cause phase problems and a very narrow scatter characteristic in the upper midrange area. Klipsch solved this by sliding the crossover frequency between these and their tweeters down to a low 1.750 Hz.

Their sound aside; the cabinets are very deep, and need a good distance from the wall - so they would take up to much room and be to dominant in my livingroom.

agk

30-07-2016, 00:31

I favour 3 or more way speakers myself. Has to be done well but when done well its the mutts nuts.
Let the tweeter do the treble, the mid do the mid and woofer do the bass.

danilo

30-07-2016, 03:00

Macca

30-07-2016, 07:12

Erm.. Let it go. You made a misstep, end of.

LOL - no I didn't. I'll find you the technical explanation if you insist. Every day's a school day.

fatmarley

30-07-2016, 08:36

I found that a 3-way using the same mid driver as a 2-way plays complicated music with better clarity, but a simple vocal was slightly cleaner on the 2-way. The midrange series capacitor that you have to use to form the high pass filter on the mid does colour the sound a bit depending on what you use BUT a nice big woofer producing the lower mids gives male vocals more authority.

Yomanze

30-07-2016, 09:47

It is a lot easier to get 2 ways right.

In my typical English terraced living room 2 way standmounts are the way to go. Bringing in 3 way floorstanders would overwhelm the room and get the neighbours chatting. As it turns out I do a lot of listening at low to medium volume.

So, what you go for is room dependent, as mentioned above you'll lose a bit of 'cohesiveness' between the mid bass and midrange with a three way, but get more range & probably more resolution. To me though a 2 way, in my room, is more natural...

Jimbo

30-07-2016, 18:24

Too blingy and look like you'd need a very large room indeed.
The only multi driver speakers I ever liked was the Wharfedale E70's and E90's. I was a kid then in the 1970's and they just looked the biz to me at the time.
I'm a lot older and wiser now. Next speakers will likely be Spendor S8e or more likely the S9 (non e) which has somehow caught my eye / radar.

Can't go wrong with Spendors Rob, wish you could hear my SP2's, simple 2 way speakers with very simple crossover but they sound wonderful, so much so they have stayed with me for 30 years!

When they do die I will have a listen to the D7.

Macca

31-07-2016, 09:54

The combination of the horn throat and the inner circumference of the cone effectively makes a mid-range driver. You'd need someone like Paul RFC to explain the exact technicalities.

http://www.44bx.com/tannoy/history.html

Drawing from his knowledge of high efficiency products made for the high quality public address market, the Chief Engineer, Mr. Ronnie H Rackham combined a high frequency compression horn drive unit concentrically with a 15" direct radiating bass driver. His skill in designing wide band horn systems married the two drivers together so that the flare shape of the 15" bass unit continued the flare rate of the high frequency unit.

It was this important part of the design process that conceived a very low coloration horn device. Because the HF horn had a very large mouth diameter it had an inherently low cut off frequency.

What I said :)

walpurgis

31-07-2016, 10:54

http://www.44bx.com/tannoy/history.html

Drawing from his knowledge of high efficiency products made for the high quality public address market, the Chief Engineer, Mr. Ronnie H Rackham combined a high frequency compression horn drive unit concentrically with a 15" direct radiating bass driver. His skill in designing wide band horn systems married the two drivers together so that the flare shape of the 15" bass unit continued the flare rate of the high frequency unit.

It was this important part of the design process that conceived a very low coloration horn device. Because the HF horn had a very large mouth diameter it had an inherently low cut off frequency.

What I said :)

Not really Martin. Tannoy DC fans will be aware of the way the tweeter horn is augmented by the cone flare, but this does not mean it is a 'three way speaker'. It is merely an extremely well inegrated two way.

As an aside to this. On quite a few Tannoys I've seen, the transition from the end of the tweeter horn into the back of the bass cone flare is poor due to low quality control. The bass coil former extending significantly beyond the start of the cone flare where the bass cone is bonded to the coil former. This leaves the tweeter firing through a parallel sided 'tube' for maybe 15mm, missing the beginning of the cone flare completely. This results in reflections across the 'tube' and also negative effects on the horn transition. It can be cured though.

Macca

31-07-2016, 11:32

My contention was that in practice it behaves like a 3 way even though it isn't one.

The problem with any normal 2 way is that there is one driver - the bass/mid - doing almost of the work. Tweeters in reality add very little except air, space and sparkle. If you want good bass and good midrange together then that is a huge compromise, unless you tune most of the bass out. But people don't tend to like bass-shy speakers, or having to use a subwoofer.

Personally I like the JBL solution of using a fifteen inch to do the heavy lifting and cross over to a compression driver in a cell horn quite low, that covers the whole sensitive area, then add a supertweeter for the frequencies above 6 or so KHz so it sounds 'hi-fi'. Good dispersion and gets the crossover down nice and low and out of harm's way. The 4365 is one of the best speakers I have ever heard and is a lot cheaper than some efforts that are far less accomplished (although still into 5 figures)

http://eu.jbl.com/tl_files/catalog//jbl/home/Specsheets/Studio%20Monitor/4365/Specification%20Sheet%20-%20Studio%20Monitor%204365%20(English%20EU).pdf

I'm kicking around the idea of building something that works in a similar way for about a 5th of the price.

walpurgis

31-07-2016, 11:40

You'd certainly like the big Altecs then Martin.

Macca

31-07-2016, 11:49

I suspect so! But never heard any.

walpurgis

31-07-2016, 11:56

Model 19 perhaps? :)

http://i65.tinypic.com/2lax83p.jpg

Macca

31-07-2016, 12:24

Tasty! Yes something along those lines. Need to cheat a bit as the compression drivers are big money. Might ude a BMR instead.

walpurgis

31-07-2016, 14:27

compression drivers are big money.

Not really. Look at the professional stuff on eBay. Compression drivers from around a tenner and horns £15 upwards. Obviously the more you pay the better they are likely to be.

Reffc

31-07-2016, 14:48

The combination of the horn throat and the inner circumference of the cone effectively makes a mid-range driver. You'd need someone like Paul RFC to explain the exact technicalities.

Martin is correct.

A Tannoy DC is essentially operating acoustically as 3-way drive unit.

At frequencies up to 1KHz, the bass cone does most of the work and it's rolled off at a KHz (MG/HPD for example) using a 2 pole electrical (but closer to 3rd order acoustic). The compression driver of the mid horn has already started coming in at this point and does indeed use the curved bass cone as a midrange horn with a flare rate approximating something like a tractrix horn which ensures a very smooth transition from the bass frequencies up to the high frequencies, with the added benefit of providing much lower distortion and higher efficiency that a conventional mid-range speaker and also has very good stereo imaging properties due to its dispersion characteristics.

Higher frequencies are handled purely by the central 2.5 inch horn (MG and HPDs plus later Silvers) in vintage DCs with the cut in frequency dictated by the horn mouth (generating a spherical wave from the point of phase corrected propagation in front of the pepperpot up to the horn mouth. This is a clever design which is lower in distortion and able to provide faster transient behaviour than most conventional 3 way designs without the need for a 3 way crossover.

In order to increase SPLs further and improve power handling, lower distortion at crossover frequency, the MG was changed to stiffen the cone using the girdercoustic ribs and a tannopplas foam surround was introduced to lower free air resonance which extends bass frequencies a little lower. This design became the HPD.

It makes Tannoy DCs sensitive, capable of high SPLs for lowish power, and offers comparatively very low distortions through the lower and mid range up to around 3KHz where horn resonance needs to be tamed. The response, as with all horn type HF drive units is a rising response, notable above 5KHz hence the roll-off filter after the HF main filter. The original autoformer design calls for a steepening of this roll-off filter to maintain a smooth response or ghosted response, hence roll-off switches on original designs. Following a lot of research it has become more widely accepted that it is perfectly feasible and indeed desirable do do away with the autoformer where a raised HF is not required (with appropriate electrical compensation to ensure the correct electrical Q) and thus the need for an adjustable roll off filter. Simpler is better...and improves things further.

Arkless Electronics

31-07-2016, 15:04

walpurgis

31-07-2016, 15:19

Reffc

31-07-2016, 15:35

There are two voice coils so it's two way IMO. How many ways is a single driver used full range? One? or is it many?... as different parts of the cone and central dust cover/whizzer cone resonate and radiate at different frequencies?

Point missed Jez. It's a two way (as you say, two voice coils) but specifically designed to act acoustically like a 3 way. The HF horn if housed in it's own separate enclosure would not have the power handling capability of delivering the SPL required of it at the crossover frequency if it didn't use the bass-cone as a horn. That's what Tannoy intended and what they very successfully managed to do. One can argue semantics all day long but the fact is that it acts like a 3 way, that it has high sensitivity (and efficiency) for relatively low distortion. None of this was by chance, it was by design. It does it all to way better effect than any FR driver using whizzer cones (and to clarify, not all "FR" drivers use whizzer cones and very few are even full range at all or anything close to it. Most also deliver audibly worse distortion and fail to deliver any bass). It's simply not a comparable design. All I've done is to take the time and trouble to explain the DC design, but there will always be someone who wishes to argue. Over and out. :rolleyes:

Arkless Electronics

31-07-2016, 15:47

Point missed Jez. It's a two way (as you say, two voice coils) but specifically designed to act acoustically like a 3 way. The HF horn if housed in it's own separate enclosure would not have the power handling capability of delivering the SPL required of it at the crossover frequency if it didn't use the bass-cone as a horn. That's what Tannoy intended and what they very successfully managed to do. One can argue semantics all day long but the fact is that it acts like a 3 way, that it has high sensitivity (and efficiency) for relatively low distortion. None of this was by chance, it was by design. All I've done is to take the time and trouble to explain the design, but there will always be someone who wishes to argue. Over and out. :rolleyes:

Semantics as you say.... I see it the way Geoff describes... which is an example of what I described above that... IMO just using the bass cone as part of the horn for the tweeter (not much choice in a coaxial!) does not make it 3 way any more than adding an ABR to augment the bass from a two way box makes it three way. YMMV :)

struth

31-07-2016, 15:54

Horses for courses

Reffc

31-07-2016, 16:15

Semantics as you say.... I see it the way Geoff describes... which is an example of what I described above that... IMO just using the bass cone as part of the horn for the tweeter (not much choice in a coaxial!) does not make it 3 way any more than adding an ABR to augment the bass from a two way box makes it three way. YMMV :)

Again, you miss the point Jez. Lets start with a clean sheet. The DC is a solution, perhaps the only really successful one ever developed, to create a perfect point source capable of extending to almost full frequency using two voicecoils mounted ostensibly in one pole piece to create a smooth transition that if in separate enclosures or mounting planes would not have been possible. Better to consider them is a complex two-way which covers the same spectrum as a 3-way. It is not comparable with a FR drive unit as almost all such drive units are flawed to some extent and most really only perform well at mid range frequencies. The design is such that clever shaping and use of the bass cone ostensibly creates a very efficient mid horn driven by the HF unit, which also handles the higher frequencies, hence a 2-way which acts acoustically as a true 3 way. It's a good design, efficient, and low in distortion.

The idea behind the DC was to produce a unit capable of a true point source with a true spherical wave form propagating from the centre of the driver across ALL frequencies, resulting in a near 90 degree dispersion both vertically and horizontally, and resulting in not just phase-correct sound but a more natural sound with a true point source.

It matters less whether one considers it a 2 or a 3 way when one considers the design as a whole. It also depends on what definition one chooses to apply, but again, all I've done is to try and offer an explanation of how it works. Martin suggested that I might offer an explanation, which I have. The fact remains that he is correct in his understanding that it behaves acoustically as a 3-way using just two drive units, but really, that is only one small part of the appeal of the design as I've tried to outline above.

walpurgis

31-07-2016, 16:17

Arkless Electronics

31-07-2016, 16:32

Again, you miss the point Jez. Lets start with a clean sheet. The DC is a solution, perhaps the only really successful one ever developed, to create a perfect point source capable of extending to almost full frequency using two voicecoils mounted ostensibly in one pole piece to create a smooth transition that if in separate enclosures or mounting planes would not have been possible. Better to consider them is a complex two-way which covers the same spectrum as a 3-way. It is not comparable with a FR drive unit as almost all such drive units are flawed to some extent and most really only perform well at mid range frequencies. The design is such that clever shaping and use of the bass cone ostensibly creates a very efficient mid horn driven by the HF unit, which also handles the higher frequencies, hence a 2-way which acts acoustically as a true 3 way. It's a good design, efficient, and low in distortion.

The idea behind the DC was to produce a unit capable of a true point source with a true spherical wave form propagating from the centre of the driver across ALL frequencies, resulting in a near 90 degree dispersion both vertically and horizontally, and resulting in not just phase-correct sound but a more natural sound with a true point source.

It matters less whether one considers it a 2 or a 3 way when one considers the design as a whole. It also depends on what definition one chooses to apply, but again, all I've done is to try and offer an explanation of how it works. Martin suggested that I might offer an explanation, which I have. The fact remains that he is correct in his understanding that it behaves acoustically as a 3-way using just two drive units, but really, that is only one small part of the appeal of the design as I've tried to outline above.

I do not miss the point even slightly! We have it seems different criteria for what counts as 2 or 3 way.
The Quad ESL63 also acts a s a point source... and the KEF Uni-Q. personally I prefer either to any Tannoy by a large margin but as someone said above, horses for courses. I agree on full range single drivers though... never heard one I could tolerate.

fatmarley

31-07-2016, 17:08

I've decided that because the tweeter is in the centre of the cone and you can't see it, that it is actually a 1-way speaker.

walpurgis

31-07-2016, 17:13

I've decided that because the tweeter is in the centre of the cone and you can't see it, that it is actually a 1-way speaker.

Ah. Pure logic. I like it! :D

Sovereign

31-07-2016, 19:57

There are exceptions. Altec Lansing developed the 'Biflex' driver shown here:

http://i65.tinypic.com/29fco5i.jpg

The cone being of two parts. Inner acting as midrange and bass and outer as bass only. The 'crossover' (if you will) being a mechanical decoupling ring.

In the original Santana speaker model this produced a speaker which one could argue is two way or three way. As here:

http://i63.tinypic.com/29e15jk.jpg

I believe this type of driver design has been used by other manufacturers as well.

By the way. I've heard the Santana and can't say I was particulary struck by the sound, but the tweeter is a crap quality generic item anyway, variants also being used by KLH, Marantz, Bolivar(JBL) and Studiocraft(Bose), amongst others.

.

Interesting thread this one.
I currently have the three way DIY Lampizator P17 speakers, which I have always found to be excellent, to such an extent that I have kept them for about four years which is a long time for me. I know Lampizator are better known for their DACs but the blokes DIY speaker musings are not half bad at all.
http://i1138.photobucket.com/albums/n533/SovereignKing/IMG_1399.jpg (http://s1138.photobucket.com/user/SovereignKing/media/IMG_1399.jpg.html)

Off the back of this I have always fancied upgrading to Lampizator's P23 speaker which uses the Altec Lancing 420A as used in the Santana speaker, Lampizator rate this driver very highly, but as you say maybe it is crap or maybe it is the tweeter that lets the sound of the speaker down.
I have a good quality pair of the Altec Lancing 420As along with the Altec Lancing 806 horned tweeters for the P23 design.
http://i1138.photobucket.com/albums/n533/SovereignKing/image_26.jpeg (http://s1138.photobucket.com/user/SovereignKing/media/image_26.jpeg.html)e

http://lampizator.eu/SPEAKERS/PROJECTS/P23/Aaltec_Rusinos%20_Maximus_Lampizator.html
There is a lot of blurb at the beginning of this page but it gets interesting towards the end.
As I have all the drivers and some time on my hands I plan to literally knock up an open baffle and have a play around and see what sounds best, it any good at all.

walpurgis

31-07-2016, 20:10

This is the type of tweeter used in the earlier Santana. These being from a KLH speaker.

http://i65.tinypic.com/ju732e.jpg

Reffc

31-07-2016, 21:48

Out of curiosity. If the Tannoy dual concentric unit was separated into two distinct drivers. The compression driver & magnet assembly being mounted to a horn of simliar size and profile to the dual concentric's bass cone and the bass section of the driver with another magnet assembly, utilised just for bass. What would that be likely to equate to? (obviously two drive units would need to be cannibalised to furnish enough parts)

It would be a rather pointless exercise Geoff because of the loss of point source and everything that entails but you'd end up with a 2 way with the compression driver and short horn having its sensitivity boosted by the additional waveguide. I get your point, but the concentric design allows for a doubling up of the bass also becoming the waveguide hence the "extra" horn used by the HF driver. A for the uni-Q, it isn't a patch on a well sorted DC with appropriately well sorted crossover in a decent cabinet. No comparison whatsoever imho. The Tannoy DC remains the most successful DC design ever made for good reason. Trouble is, there's way too many poorly sorted examples in circulation with a good many owners not realising their full potential. There's a world of difference between an average DC in original cab with original crossover and one that's been properly sorted. Completely different end result. Personally, I can't live with the DCs in standard form, but sorted, they're amazingly neutral, detailed and very refined...the opposite of what they can sometime sound like in original form!

walpurgis

31-07-2016, 22:02

I get your point

Thought you would :). And I agree with the rest of your reply Paul.

I've heard the Altec dual concentric drivers and not been overwhelmed. I'd like a listen to the vintage BTH and Whitely Stentorian models though.

paulf-2007

01-08-2016, 06:59

Tried most things and always come back to single driver with a helper tweeter. I have two pairs of single driver bass reflex speakers I diy'ed with a ribbon tweeter sat on top that I use in my office and have used in the main room but now have Zu omen, basically the same, 10" wide range with a tweeter for the very top end, difference being they do epic bass. I have done open baffle, nice in its own way and horns, with 15" bass drivers. What I don't like is the American way of running the woofer into the midrange, as someone mentioned here, the midrange should not have a crossover between 300hz and 2000hz, that's my preference, I have tried various low pass points from 1500-3000hz.

Beobloke

01-08-2016, 09:30

To return to the OP's question, just like most hi-fi debates, I'm afraid there are no absolutes. Theoretically, 3-ways should be better, but a good 2-way will be better than a poorly designed 3-way (and vice versa).

jandl100

01-08-2016, 17:52

4 way for me, in my speakers of choice.

But the old adage of a good 3 way always being better than a good 2 way has a lot going for it.

I've never heard a 1 way I could tolerate, apart from full range electrostatics but that's a different set of principles anyway - the frequency response of a single cone driver seems to go all over the place when asked to cover so many octaves (cone breakup resonances?) and it ends up terminally coloured, imo.
Personally I think Tannoy DC drivers suffer from that as well.

Macca

01-08-2016, 18:16

In the case of Tannoy DC it must have been the cabs or crossovers or both. You can get them to measure almost flat. There's still going to be colouration but from the driver materials, not big humps and dips in the FR.

Barry

03-08-2016, 01:55

There is also going to be Doppler intermodulation of the compression tweeter by the moving horn that is the woofer cone. It is to Tannoy's credit that this IM is sufficiently low.

Reffc

03-08-2016, 08:07

Macca

03-08-2016, 11:24

The RFC Canterbury is the most neutral-sounding Tannoy DC I have heard. In fact the mid-band is one of the most neutral I have heard of any speaker, electrostatics excepted. I wasn't that keen on Pauls' Rega CD player but with vinyl on his 401 it was a 'studio' experience.

RobbieGong

03-08-2016, 11:55

Can't go wrong with Spendors Rob, wish you could hear my SP2's, simple 2 way speakers with very simple crossover but they sound wonderful, so much so they have stayed with me for 30 years!

When they do die I will have a listen to the D7.

This is what I've been led to believe Jimbo. Musical, Great in the mids, detailed and non fatiguing which are musts for me and as per my Mission 752 Freedoms. My next speakers will defo be Spendors.
Never ever heard a pair strangely, however I know what I like and have made some great punts over the years on the back of extensive researching, reading lots of customer reviews etc and knowing the sound I like and dont like which actually helps a lot ;)

Barry

03-08-2016, 16:38

Such effects are very limited Barry because of two things. Firstly, acoustic slopes are relatively steep and secondly, the Qts of the driver units is very low, typically around 0.2 for the vintage series of drivers. This means that very little energy is stored in the drive unit out of band, and combined with the slopes, the effect is very minimal. Distortion is higher for the horn resonance area hence the need for the notch filter, but even that can be well controlled to the point of being all but inaudible. Martin has heard the effects of well controlled DCs in very rigid cabinets and I think can attest to the neutral and very linear acoustic properties of a well set up DC. The crossover region on the RFC Canterburys for example is all but inaudible (the critical area here lying between 700 and 1300 Hz), even to the golden eared amongst us ;)

I’m not sure I understand what you’re saying when talking about driver resonances and their low Q values. I was simply refering to the modulation of the high frequencies by the low frequencies in concentric speakers, either of the Altec Lansing coaxial type or that of Tannoy dual concentric type.

https://en.wikipedia.org/wiki/Dual-concentric_speakers

Dupont, Edward; Lipshitz, Stanley P. (September 2010)
“Modeling the Intermodulation Distortion of Coaxial Loudspeakers”.
Audio Engineering Society. Retrieved May 1, 2011

Reffc

03-08-2016, 16:59

I’m not sure I understand what you’re saying when talking about driver resonances and their low Q values. I was simply refering to the modulation of the high frequencies by the low frequencies in concentric speakers, either of the Altec Lansing coaxial type or that of Tannoy dual concentric type.

https://en.wikipedia.org/wiki/Dual-concentric_speakers

Dupont, Edward; Lipshitz, Stanley P. (September 2010)
“Modeling the Intermodulation Distortion of Coaxial Loudspeakers”.
Audio Engineering Society. Retrieved May 1, 2011

I assumed that you meant the out of band distortions caused if the bass cone was still operating into the upper mids Barry, my mistake. Yes, in theory, inter-modulation distortion can be present when you have two coincident sources outputting different frequencies with modulation of frequencies occurring as a result, more precisely, modulation of HF due to the cone displacement of the LF. In practice, it really isn't that much of an issue with Tannoy DCs and your ears will tell you that when listening to a well set up pair. Also, by the time you get to the crossover point, the physical movement of the cone drops right off, so limiting non-linear outputs which could be caused by phase differences induced if cone movement was significant at crossover. This is an area which could have given a lot of trouble but where Tannoy seem to have done a decent job. Once again, the most audible distortion with many DCs is the horn resonance which occurs way above crossover or in the case of home brewed crossovers using the wrong values for LF inductors, LF cone resonance above 1KHz can introduce audible distortion at higher SPLs. These issues can be especially notable with female vocals at upper registers, and with some piano recordings, but in the case of DC's this can thankfully be all but cured by appropriate crossover design.