Cones

[RandomBass]

Brother of the famous 'Clive', and their lesser known sister 'Press'?

So sorry

[LukeFRC]

[quote name='Bill Fitzmaurice' timestamp='1387162711' post='2308924']
What they've done is to take a bass reflex cab and put a reflector inside that directs the driver rear wave out the ports. It's been known since the 1940s that if you do that the front and rear waves will meet at various angles of phase, resulting in major reponse peaks and valleys. And since the 1940s bass reflex cabs have used damping inside the cab to prevent that, allowing only bass frequencies close to the port tuning frequency to come from the port. Damping the rear wave is one of the most basic tenets of speaker design, but these guys have managed not to learn that. The other feature they use is cross-fired drivers, but that's hardly new or unique. They use extremely expensive drivers, so their prices are off the charts. But they look cool.
[/quote] Hmmm I think the back side is being treated as a horn of some kind. I expect when we see the inside there will be lots of curves, and circle type things. And phasing problems.
thing that gets me is that people will spend money on something without knowing how it's working.

[funkle]

[quote name='Bill Fitzmaurice' timestamp='1387162711' post='2308924']
What they've done is to take a bass reflex cab and put a reflector inside that directs the driver rear wave out the ports.
[/quote]

Thank you for the explanation. I'd been reading those threads but stopped when I realised actual factual information was not going to be forthcoming soon. I'd like to see some charts for those incredible claims, please and thank you...

As a contrast, shopping for PA gear is in one sense very simple. I can obtain freq/SPL charts and polar response charts very easily from most manufacturer websites. The information provided seems accurate (weight, dimensions, etc) and they provide reasonable -3dB and -10dB points. If they don't, I can choose not to consider them and still have plenty of choice. Not so in bass cab land. Alex at BF and the BFM designs do the best job I've seen so far in giving useful info.

I'd really like to see bass cab makers provide the same info that seems to be standard in the pro audio industry. It doesn't tell you how it is going to sound, necessarily, but it does provide useful factual information.

/rant

[funkle]

[quote name='Bill Fitzmaurice' timestamp='1387146785' post='2308809']
In a cost no object design I'd go even lower than I did with the Simplexx, but for most builders cost is an object.
[/quote]

I would be very interested to know what the 'cost no object' BFM solution would look like, if you cared to design it. There is a niche for high performance bass reflex cabs, currently occupied (IMO) by Audiokinesis, Acme, BF, Baer, Greenboy, etc, all making slightly different trade-offs. The Simplexx cabs look like an elegant mid cost solution to use individual labour to cancel out the cost of using better quality drivers (if desired). What does the 'high end' BFM solution look like?

Edited December 18, 2013 by funkle

[xgsjx]

[quote name='Phil Starr' timestamp='1387187050' post='2309017']
That's all fair,

I hope you didn't think it was a personal thing I'm an ex science teacher and I can't resist my instinct against the unqualified statement. My wife is an English teacher and can't resist correcting my grammar. Hope it opened up the debate though.
[/quote]

I didn't think it was personal.

I'm always keen to know how &why things work. Helps me get a good sound at gigs.

[Phil Starr]

[quote name='stevie' timestamp='1387213455' post='2309478']
Phil, I appreciate that you can put a more complex spin on it, but let’s not compare apples and oranges. Yes, you can make an expensive 15 that will have better midrange than a cheap 10 and you can even make a 10 that has no midrange at all. But it is still the case that (ceteris paribus) large cones are simply not as good at reproducing higher frequencies as smaller cones, and that the larger the cone the lower it tends to break up.

By the same token, when a lot of air has to be moved you need a large cone area. It’s the balancing act that makes speaker design so interesting, don’t you think?
[/quote]
Hi Stevie,
You're right, there's a bit of me that watches from afar and says 'you can't still be interested in all this can you?' but it is that combination of science and craft that I just can't leave alone, plus the sheer joy of making very loud music! It'll be a sad day for me if they come up with a perfect replacement for the moving coil loudspeaker.

There were a couple of things behind my post. Mainly I don't think most of the people reading here will realise how much of the sound we hear is due to the cone flexing. I've never seen a discussion of it on BC. Most people I suspect think of the cone moving backwards and forwards as a stiff piston and think the sound is coming from the whole cone. You'll know it isn't but others won't and it has relevance for bass drivers in particular. IMO it is this that gives speakers their 'sound' more than their bass response in the bottom two octaves. Because of the way we work with Thiele/Small equations and the programs like WinISD that run them we tend to concentrate on this a lot, but our ears are so much more sensitive to what is going on in the 1-5kHz (midrange) and we tend collectively to gloss over that a bit.

A couple of years ago I built a 4x10 as a kind of test bed for developing a bass cab, I used two different drivers in it, the Fane soveriegn 10-125 and 10-275.The first with a light cone and a smaller magnet and the second a heavier cone, larger magnet and stiffer suspension. the second one has a cleaner and slightly more extended bass response but only really extended up to 3000hz. This clearly wasn't enough without a midrange driver and they are currently doing duty in a pair of stage monitors crossing over to horns at 2k The thinner more flexible cones in the cheaper 10-125's give an output up to about 4500Hz and sound much better as bass speakers, I still use them in a 2x10.

This is my real bugbear coming from designing hi-fi speakers, I'm not convinced there's a lot of design going into commercially available drive units, There's a lot of over damped, low excursion drivers where they seem to have just stuck a bigger magnet on a cheaper design without considering the use for which the driver is intended, Just a marketing opportunity with no need to re-tool. Speakers recommended as bass drivers which are just unsuitable due to under damping, huge Vas values and low excursion and of course little control over the cone's behaviour under break up, with some Eminence units having 9dB peaks with very sharp peaks and troughs in the frequency response showing little damping of cone resonance.

It seems as if Alex Claber is having some input into the design of his drive units, that's a luxury I'd love to have.

[LukeFRC]

Interesting post Phil, cheers

[alexclaber]

[quote name='Phil Starr' timestamp='1387279120' post='2310074']It seems as if Alex Claber is having some input into the design of his drive units, that's a luxury I'd love to have.[/quote]

There's a bit about it over here: http://barefacedbass.com/technical-information/generation-three-development.htm

It was a very long process but on the plus side we learnt a lot on the way which changed our goals, so it worked out best in the end. Didn't feel it at the time though, R&D is expensive and I just wanted to get on and get the new designs happening!

Here's something else to consider - what's the surround doing? And if you haven't thought about it already, what's the dustcap doing? And what happens at the joints of dustcap to cone and cone to surround?

[LawrenceH]

Agree very much with Phil's post above. T/S params make it too easy to focus on the bottom one-and-a-half octaves, the mids will dominate tonal perception and the complex material behaviour/geometry of the cone, dustcap etc will have crucial effects that are not easy to measure (compared to freq response).

Also agree with Bill et al that those Big E speakers look like a complete load of rubbish and the descriptions of how they sound scream 'comb filtering' to me!

[Phil Starr]

Oh, Bill is spot on about all the mystic mumbo jumbo on the Big E website. I expect they also use the vibrational power of crystals to reach into the fifth dimension.

[alexclaber]

This is a really great document - I want a big paper copy to stick on our factory wall!

http://www.klippel.de/fileadmin/klippel/Files/Know_How/Literature/Papers/KLIPPEL_Cone_Vibration_Poster.pdf

[LukeFRC]

[quote name='alexclaber' timestamp='1387382313' post='2311344']
This is a really great document - I want a big paper copy to stick on our factory wall!

[url="http://www.klippel.de/fileadmin/klippel/Files/Know_How/Literature/Papers/KLIPPEL_Cone_Vibration_Poster.pdf"]http://www.klippel.d...tion_Poster.pdf[/url]
[/quote]

I'll put my hands up and say I understood barely half of that!


EDIT: the poster, not your post...

Edited December 19, 2013 by LukeFRC

[stevie]

[quote name='Phil Starr' timestamp='1387279120' post='2310074']
Because of the way we work with Thiele/Small equations and the programs like WinISD that run them we tend to concentrate on this a lot, but our ears are so much more sensitive to what is going on in the 1-5kHz (midrange) and we tend collectively to gloss over that a bit.
[/quote]

I couldn't agree more! The 1-2kHz region is absolutely crucial to the sound of the bass guitar (as the recording experts will no doubt confirm). Yet when we play live, most bass cabs are unable to reproduce that area properly. I'm a great believer in having a separate midrange driver to take care of the upper mids.

[quote name='Phil Starr' timestamp='1387279120' post='2310074']
This is my real bugbear coming from designing hi-fi speakers, I'm not convinced there's a lot of design going into commercially available drive units, There's a lot of over damped, low excursion drivers where they seem to have just stuck a bigger magnet on a cheaper design without considering the use for which the driver is intended, Just a marketing opportunity with no need to re-tool. Speakers recommended as bass drivers which are just unsuitable due to under damping, huge Vas values and low excursion and of course little control over the cone's behaviour under break up, with some Eminence units having 9dB peaks with very sharp peaks and troughs in the frequency response showing little damping of cone resonance.
[/quote]

You're speaking my language, Phil. Some of the drivers I've seen in big-name cabs are just embarrassing. But if people want cheap, that's what they get.

[quote name='Phil Starr' timestamp='1387279120' post='2310074']It seems as if Alex Claber is having some input into the design of his drive units, that's a luxury I'd love to have.
[/quote]

Yes, well, we know that Alex is big on hyperbole (hi Alex! ). What input do you want? The premium drive units, the very best that the drive unit manufacturers can produce and the ones that the big companies like Meyer, QSC, Clair, EAW, Nexo, Martin etc. use, are all standard models that are available to you as a consumer.

[LawrenceH]

[quote name='stevie' timestamp='1387487457' post='2312685']
Yes, well, we know that Alex is big on hyperbole (hi Alex! ). What input do you want? The premium drive units, the very best that the drive unit manufacturers can produce and the ones that the big companies like Meyer, QSC, Clair, EAW, Nexo, Martin etc. use, are all standard models that are available to you as a consumer.
[/quote]

I can't say Ive hunted the earth, but I have not come across 12" drivers that will do +/-10mm clean excursion as measured by any method that also give similar midrange sensitivity and extension as Alex claims for his (and I for one am happy to take his figures at face value). The ones with comparable linear travel weigh a lot even with neo magnets. The dispersion tends to narrow lower down on the long-excursion, big voicecoil diam subs too, which goes back to the original topic - cone construction.

Although I think the Eminence KL series were nothing special by today's standards, it seems to me like Alex has a genuine USP with the new line. For PA it makes more sense to separate sub from mid-bass anyway so the goals are a little different. But yes, the standard (and eye-wateringly expensive) B&C drivers in all those big PA boxes sound pretty good to me.

[LawrenceH]

[quote name='stevie' timestamp='1387487457' post='2312685']
I couldn't agree more! The 1-2kHz region is absolutely crucial to the sound of the bass guitar (as the recording experts will no doubt confirm). Yet when we play live, most bass cabs are unable to reproduce that area properly. I'm a great believer in having a separate midrange driver to take care of the upper mids.
[/quote]

Funnily enough I've just been tweaking exactly this region in a mix. But Ive flip-flopped on midrange drivers and now I think I favour two-way, only using nicer comp drivers that go adequately low not to leave a big dispersion hole. I actually like the 1-2kHz region from a nice 10 or 12" PA driver for bass. I've got several Celestion drivers and they all sound really good in this region IMO.

[stevie]

[quote name='LawrenceH' timestamp='1387489181' post='2312707']
I can't say Ive hunted the earth, but I have not come across 12" drivers that will do +/-10mm clean excursion as measured by any method that also give similar midrange sensitivity and extension as Alex claims for his (and I for one am happy to take his figures at face value). The ones with comparable linear travel weigh a lot even with neo magnets. The dispersion tends to narrow lower down on the long-excursion, big voicecoil diam subs too, which goes back to the original topic - cone construction.
[/quote]

Faital do a 12 with a specified 9.5mm excursion, although it's winding depth - magnetic gap depth) / 2 + (magnetic gap depth / 3. You can get them from Blue Aran. No need for 2 years R&D (yes, call me cynical if you like). The model number is 12HP1020.

[quote name='LawrenceH' timestamp='1387489181' post='2312707']
Although I think the Eminence KL series were nothing special by today's standards, it seems to me like Alex has a genuine USP with the new line. For PA it makes more sense to separate sub from mid-bass anyway so the goals are a little different. But yes, the standard (and eye-wateringly expensive) B&C drivers in all those big PA boxes sound pretty good to me.
[/quote]
I still rate the Eminence Kappalite LFs for the money. The bass/mids are a bit meh but still better than what you find in 90% of bass cabs. I agree, Alex seems to be using a very good driver.

[stevie]

[quote name='LawrenceH' timestamp='1387489919' post='2312715']
Funnily enough I've just been tweaking exactly this region in a mix. But Ive flip-flopped on midrange drivers and now I think I favour two-way, only using nicer comp drivers that go adequately low not to leave a big dispersion hole. I actually like the 1-2kHz region from a nice 10 or 12" PA driver for bass. I've got several Celestion drivers and they all sound really good in this region IMO.
[/quote]

Yes, I know exactly where you're coming from. To do it properly with a compression driver you need either an expensive 1" (like an Italian one or a BMS) or preferably a 1.4". Then you have to find a nice-sounding horn. Unless you really need that 5-10kHz response, a cone driver will do as good a job, go lower, and be a lot cheaper (if you ignore the cost of the crossover ).
I've often wondered what a 2" compression driver would sound like with bass - with the right horn, of course. Awesome, I expect. Tens and twelves can certainly sound really nice in that area also (and some of the Celestions I've tried have sounded wonderful), but they can't get round the beaming problem.

Edited December 19, 2013 by stevie

[funkle]

[quote name='stevie' timestamp='1387487457' post='2312685']
The premium drive units, the very best that the drive unit manufacturers can produce and the ones that the big companies like Meyer, QSC, Clair, EAW, Nexo, Martin etc. use, are all standard models that are available to you as a consumer.
[/quote]

I'd like to know models of these, if you'd be happy enough to point me in the right direction? As a relative newbie to this I'd like to be able to look at the driver spec sheets...if I can...

[quote name='stevie' timestamp='1387492375' post='2312746']
Yes, I know exactly where you're coming from. To do it properly with a compression driver you need either an expensive 1" (like an Italian one or a BMS) or preferably a 1.4". Then you have to find a nice-sounding horn. Unless you really need that 5-10kHz response, a cone driver will do as good a job, go lower, and be a lot cheaper (if you ignore the cost of the crossover ).

I've often wondered what a 2" compression driver would sound like with bass - with the right horn, of course.
[/quote]

Again, did you have specific models in mind? (I've just bought some books on loudspeaker design and I'm trying to absorb more info on the subject.)

Thanks.

Pete

[Phil Starr]

[quote name='LawrenceH' timestamp='1387489181' post='2312707']
I can't say Ive hunted the earth, but I have not come across 12" drivers that will do +/-10mm clean excursion as measured by any method that also give similar midrange sensitivity and extension as Alex claims for his (and I for one am happy to take his figures at face value). The ones with comparable linear travel weigh a lot even with neo magnets. The dispersion tends to narrow lower down on the long-excursion, big voicecoil diam subs too, which goes back to the original topic - cone construction.


[/quote]

This is the thing, you wouldn't design a really long throw speaker unless it was working as a piston in the lower octaves and at these powers that means a rigid, and probably heavy cone. If you want a wider range then the cone has to flex, Then if you are getting most of the upper octaves radiated from the middle of the cone you can get reasonable dispersion patterns along with the increased frequency response, What you can't get is both the bass of a heavy rigid driver and the cone handling a wide frequency range at the same time. That's true whether you are developing your own drivers or like most of us trying to pick out the pearls from the commercial offerings.

I wonder if Alex ever measured the dispersion of his Kappalite based speakers?


[quote name='stevie' timestamp='1387492375' post='2312746']
Yes, I know exactly where you're coming from. To do it properly with a compression driver you need either an expensive 1" (like an Italian one or a BMS) or preferably a 1.4". Then you have to find a nice-sounding horn. Unless you really need that 5-10kHz response, a cone driver will do as good a job, go lower, and be a lot cheaper (if you ignore the cost of the crossover ).
I've often wondered what a 2" compression driver would sound like with bass - with the right horn, of course. Awesome, I expect. Tens and twelves can certainly sound really nice in that area also (and some of the Celestions I've tried have sounded wonderful), but they can't get round the beaming problem.
[/quote]

To be fair there are problems with passive crossovers too. They introduce phase shifts and alignment problems at the crossover points and having a dirty great coil in series with your drivers does affect the damping considerably, not to mention the problems associated with saturating the inductor cores at high powers. Most of my serious development came when I was designing hi-fi cabs and I came to the conclusion it was better not to crossover at all in the 1-4kHz range as crossover distortion was always more audible than compromising on drivers to bridge that midrange region. Whether that is appropriate for bass speakers is of course a different issue. Most commercial designs for hi-fi or PA are two way designs avoiding the problems of complex crossovers and can sound really quite good.

My favourite sound for bass so far is going through the PA speakers, mine have fairly long throw Beyma 12" drivers and a compression unit with a 1.75" diaphragm going through a 1" exit and crossing over at 1.6kHz, I've bought some 6" drivers that claim to go up to 10kHz and at some stage i want to experiment with them both as conventional mid-range drivers and covering almost the full range (say 150Hz up) with a sub covering the bottom two octaves.

For me the big question is what does really matter when playing live? In most situations i end up rolling off the bass because real rooms end up reinforcing the bass more than is comfortable. If the dispersion at 3kHz is restricted to 45 degrees is that OK? It might even be ideal, the width of the stage at the front row of the audience. Do i need 180 degree dispersal across the frequency range? Can you actually detect 10% distortion at 40Hz in a live band situation? How about 20%? What does that mean about Xmax calculations? All this tells us where to set the compromises of course.

[alexclaber]

I can't say that much because I don't want other manufacturers to catch on to some of what we're doing (I'm sure Stevie is rolling his eyes at this and thinking that it's just more 'hyperbole' and smoke and mirrors...) but we doing things with the new drivers that some of these posts suggest is impossible. The reason the new drivers took so long was because we were trying quite a lot of different methods to achieve key aspects of performance and some worked and some didn't and some of the things that partially worked had aspects that did work so then we took the good bit and tried another approach and so on and so forth. It was quite a journey of discovery but bloody stressful because time spent on R&D is time not spent on building cabs, doing marketing and generally making money to pay the wages, rates, rent and my own living cost!

The 12HP1020 certainly wouldn't achieve our goals. I know what if you went to John Meyer or Doug Button or someone with that level of transducer understanding, that once they understood the unique challenge of amplifying bass guitar (note that everyone posting in this thread is an expert user and we sell our cabs to everyone - including mechanically unsympathetic players in very loud bands who use very powerful amps) that they'd probably end up developing something similar to our new driver. I live in hope that it might take a while to understand the unique challenges of bass guitar because it certainly took a while for me and I think I now have a better grasp of it than anyone I know of. But nobody in the pro sound industry has tried to make something like this because they make mid-bass drivers and they make subwoofer drivers and they both have very different uses. An 'ideal' bass guitar driver needs some aspects of both plus some other aspects which are unique to it.

I've just had a look through the technical pages on our site to see if any of them can be read between the lines to get a feel for what we're doing but having scanned through them I see that I have been quite circumspect about what we're doing. Much as part of me wants to go, "ta da! How clever is that?" I shall instead say that post 39 and 40 are on the right track, post 42 doesn't address that unless bandpassed that midrange drivers all tend to have quite unique 'sounds' due to their break-up modes, 10"s and 12"s can have pretty decent dispersion from 1-2kHz with the right soft parts, and post 44's first paragraph states the 'impossible' problem that we've solved, yes of course we've measured dispersion (!), and I agree about passive crossovers.

Hope that's not too annoying a post, I would love to say more but I don't think that doing so would be a sensible business decision! (I have noticed that the big PA players are being more and more cagey about what they're up to too, to my great disappointment because I've learnt a lot from their writings).

[Bill Fitzmaurice]

[quote name='LukeFRC' timestamp='1387220716' post='2309566']
Hmmm I think the back side is being treated as a horn of some kind.
[/quote]They claim that it's a waveguide, based on the fact that it's tapered. A taper does not a waveguide or horn make. It's a tapered ducted port.

[quote]I would be very interested to know what the 'cost no object' BFM solution would look like, if you cared to design it. [/quote]Simplexx is a cost no object bass reflex. There's only so much you can do with a bass reflex. You can load it with more expensive drivers, but otherwise that's about it.
[quote]There is a niche for high performance bass reflex cabs, currently occupied (IMO) by Audiokinesis, Acme, BF, Baer, Greenboy, etc,[/quote]What makes them different than more pedestrian options, like Peavey and Ampeg, is the use of premium drivers, like the Eminence Kappalites. The engineering isn't all that different, other than those that use midrange drivers instead of tweeters.
I received my Kappalite samples six months before they went on the market, I had bass reflex prototypes using them a year before Greenboy put anything out, and I designed one of the best reviewed 1x12/1x5 cabs that uses an OEM Kappalite 12 (I can't say which, as the first thing you sign when taking on a design contract is a non-disclosure agreement, as no company wants it known that they employ independent designers). I don't use a Kappalite loaded bass reflex myself, I use a Jack 12 Lite. I introduced Simplexx because I had many requests for an easy to build design that still met my quality standards, not because bass reflex is better than or even equal to what I already offered.

[LukeFRC]

Interesting thread this.
....

[RandomBass]

I go for cones that do me good. Not fussed about size. Currently I am in a long-term relationship with 12's and a 15. I had an experimental fling with 10's recently, which was a lot of fun. I just hope the 12's and 15 don't find out about it.

[bumnote]

[quote name='Phil Starr' timestamp='1387018133' post='2307413']
Sorry, but this simply isn't true, though it has become the received wisdom on BC.



I
Of course size isn't everything and there are many other factors, the electromagnetic motor and the detailed design of the cone. Alex Claber explains this perfectly fairly (from memory as his site is down) in saying there isn't a sound of a 15 or a 10" speaker. There are so many variables it couldn't be, but it isn't insignificant either, if you wanted a loud, efficient speaker driving down to 30Hz you wouldn't start with a 4" speaker.
[/quote]

What about the phil jones 5" jobbies? I have graduated to an 8x5 pjb [sometimes with an added 4x5] from an acoustic 360 driving a 2x15 and although its not as loud, I get some great sounds from it. It doesn't lack the real bottom that the ashdown 4x8 I tried had . I also use it in a jam environment where it gets used by other people either with my bass or their own. It projects nicely all round the room.

I originally thought it was a gimmick but it works really well. I would love to try on of the big rigs with 24 or more speakers

[Bill Fitzmaurice]

[quote name='bumnote' timestamp='1387564740' post='2313503']
What about the phil jones 5" jobbies?
I originally thought it was a gimmick but it works really well. I would love to try on of the big rigs with 24 or more speakers
[/quote]Displacement is displacement, whether you get there with one large driver or a whole bunch of little ones. Using smaller drivers offers the potential advantages of higher frequency response and broader dispersion, but only if you use them correctly. That means either arraying them vertically or, if clustered, bandwidth limiting, so that only the innermost drivers operate to the top of their range, while the drivers to either side are progressively low passed to lower and lower frequencies the further they are from the cabinet center. PJ doesn't do the former, I don't know if they do the latter. The disadvantage to smaller drivers is cost, as for a given displacement using larger drivers generally costs less per cubic centimeter of Vd.