MODS pls move. High Tech materials that have changed your lives for the better or failed.

[JottoSW1]

1) Does anyone know whether polished carbon finish on a gr bass cab is structural or decorative.  No implied criticism.

2) barefaced are pricey because their workforce produces clever intricacy out of (mostly??? ) plywood.?

3) a carbon / kevlar / nomex / aluminium honeycomb , whatever baffle, incorporating the main internal framework of a conventional plywood enclosure . Is this a more appropriate use of modern composites ?

 

Edited August 4 by JottoSW1
Proof reading...twice. correct inappropriate

[JottoSW1]

How light is really absolutely  required / necessary ??

[Bill Fitzmaurice]

1. Carbon fiber is very stiff while also being very light, so it is structural. But there's a lot in the GR advertising that doesn't live up to scrutiny. They're light, yes. But as to the rest...🤥

2. Barefaced braced construction is labor intensive, which adds to the cost. So do their premium drivers. There's nothing wrong with plywood.

3. A conventional plywood enclosure uses 18mm plywood with minimal bracing, if any. Whatever the material is better results come from thinner/lighter materials with extensive bracing. It's more expensive, because of the added labor cost, but you gain the benefit of lighter weight every time you pick it up.

[Downunderwonder]

56 minutes ago, JottoSW1 said:

How light is really absolutely  required / necessary ??

And how much do you want to pay?

 

A BF cabinet could possibly be made for the same price if the internals were replaced by composites, but unlikely.

 

It would be a phaff to do and be a whole lot more nasty fumes to have around the workshop. I'd charge more for the minimal up lightnessing for sure.

[Downunderwonder]

1 hour ago, JottoSW1 said:

Does anyone know whether polished carbon finish on a gr bass cab is structural or decorative.  No implied criticism

In the sense that it holds the air in, the driver in one place, and your amp up, too bloody right it is structural!

 

Bonus points for keeping the outside world from breaking it. That's the bit it is not good at, because point loads.

[BigRedX]

If you really wanted to be cost effective and/or environmentally friendly you'd ditch your bass rig altogether and either use the PA foldback or IEMs.

[Happy Jack]

1 hour ago, BigRedX said:

If you really wanted to be cost effective and/or environmentally friendly you'd ditch your bass rig altogether and either use the PA foldback or IEMs.

 

But Shirley, using the PA foldback simply passes the environmental issues further along the chain, neh? A speaker is a speaker ...

 

[Chienmortbb]

42 minutes ago, BigRedX said:

If you really wanted to be cost effective and/or environmentally friendly you'd ditch your bass rig altogether and either use the PA foldback or IEMs.

However you will need a PA  with bigger drivers/cabinets so that the audience can hear you so the savings are minimal both in cost and environmental terms.

5 hours ago, JottoSW1 said:

1) Does anyone know whether polished carbon finish on a gr bass cab is structural or decorative.  No implied criticism.

2) barefaced are pricey because their workforce produces clever intricacy out of (mostly??? ) plywood.?

3) a carbon / kevlar / nomex / aluminium honeycomb , whatever baffle, incorporating the main internal framework of a conventional plywood enclosure . Is this a more appropriate use of modern composites ?

 

Carbon Fibre, like Fibre Glass is not strong or tough until you brace it. The bracing can be made from many different materials even wood. However to achieve the lightness, you have to make some compromises. The best example of this is the nose and front wing of an F1 Car. You only need a low speed coming together to make a real mess of these carbon fibre constructions. 
 

One of the earliest composite materials that I can across was in the early Ramsa/Panasonic WS-A series. These were of a resin construction but had external moulded ribs/braces and were incredibly strong. Some of you may remember the Elephant adverts where a full grown elephant has one leg on each of four WS-A200 speakers. I still have some of theses and they are at least 30 years old. Composites are a good material but that extra bracing comes at the price of weight. While not being the heaviest cabinets, they are by no means the lightest.

 

Mike Arnopol, made some great versions of Dave ( Greenboy) Green’s designs in the US but he had to retire as the chemicals used had a massive impact on his health. 
 

So are we stuck with plywood? Yes and no. There are promising reports of the performance of bamboo ply. Bamboo is a grass  and fast growing so environmentally friendly and reportedly, light and strong. At the moment is is still hard to get and expensive. 
 

Thankfully builders like Barefaced, LFSys, BFM etc push the boundaries in sensible ways. 

 

 

[fretmeister]

CF is very strong but it is directional. Can be almost indestructible from one angle and weak as paper in another.

 

I'm just about ready to buy one of the new material Mark Bass cabs - I have no idea what they are made from and MB are being protective of the details. But I'm excited to try!

[Phil Starr]

All speaker design is a matter of compromise. Mass is one of the factors that affects the resonance of a panel but only one. Adding mass to a composite will alter it's properties and most plastics used in moulded cabs are loaded with fillers. Stiffness is important too but again not the only factor I have a hi fi cab at home made of lead. Lead certainly isn't stiff but is inherently self damping and lead panels really don't ring when you tap them. Contrary to popular opinion even Trace never used lead in their cabs If you look at historic hi fi designs you will see that not much hasn't been tried out at some time.

 

So the best material is not really something you can give a straight answer to. For portable PA weight is a real issue even for big touring rigs where you have teams of people to shift and set up the gear. Portable means it has to be tough and preferably repairable it also has to sound good. Poplar ply is lightweight but fairly soft compared with other hardwood ply. MDF is stiffer, more uniform, self-damping is good and as a man made product it is possible to optimise it for speakers, but it is dense and doesn't cope with water too well so it doesn't get used for portable PA gear too often.

 

So how light does a cab need to be? I'm a fit 70 year old and can still comfortably carry a 23 kg load a short distance. I wouldn't want to lift a 23 kg speaker above head height though. I can carry a 10kg speaker several hundred metres but I'd rather not and it will feel a lot heavier by the time I get there. Anything much more than that and weight becomes an issue I tend to grab a 10" speaker for rehearsals over my 12 because it's 2kg heavier.

 

I applaud Barefaced and others that have re-thought bass cabs but I've also felt the paels of GR Bass and Barefaced and yes they still have resonances that you can feel and hear. I've also felt quite a few old poorly braced 3/4" chipboard cabs with less panel resonance. A lot of that is down to detailed design.

 

Maybe I should stop touching up speaker cabs though, I'll get a reputation 😂

[Bill Fitzmaurice]

Bamboo laminate is a very good material, but is so much in demand in the building trades that it's hard to find and prohibitively expensive.

[Mykesbass]

49 minutes ago, Bill Fitzmaurice said:

Bamboo laminate is ... and prohibitively expensive.

Wow, just googled some sheet bamboo laminate 

[lemmywinks]

1 hour ago, Phil Starr said:

 

So how light does a cab need to be? I'm a fit 70 year old and can still comfortably carry a 23 kg load a short distance. I wouldn't want to lift a 23 kg speaker above head height though. I can carry a 10kg speaker several hundred metres but I'd rather not and it will feel a lot heavier by the time I get there. Anything much more than that and weight becomes an issue I tend to grab a 10" speaker for rehearsals over my 12 because it's 2kg heavier.

 

 

I think more cabs should have wheels and a trolley handle, I'm a recent convert and although my cab is only ~18kg so a one hand lift it does make schlepping it across car parks etc much easier.

 

More beneficial to me than any of that is being narrow/shallow enough to easily get through doors and up stairs, also having a decent recessed top handle is a massive bonus. For me there's no point saving a couple of kgs if the cab is so bulky you have to hold it away from your body to get through a doorway, you see a lot of focus on overall weight when that's just one factor in how easy it is to carry, albeit probably the most marketable one.

[Chienmortbb]

3 hours ago, fretmeister said:

CF is very strong but it is directional.

True, Airbus have been using CF wings for decades but they are extremely well braced. With corporations like Yamaha involved in loudspeaker design, as well as marine and motorcycles, you would think that CF would have been considered well before now.

[Chienmortbb]

2 hours ago, Phil Starr said:

still comfortably carry a 23 kg load a short distance.

The safe load depends on the repetitions. According to the HSE, carrying two 23Kg loads would represent ba risk of muscular skeletal injury . https://www.hse.gov.uk/pubns/indg383.pdf

[Mediocre Polymath]

I'm not an informed source on this, but from what I've heard, there seems to be  growing consensus among occupational health people that CF and similar resin- or epoxy-based composites are even worse for the human body than previously thought. The kinds of precautions needed to handle them safely, and stay in compliance with the law, are probably easy enough for a massive corporation like Boeing or Airbus to do, but would represent a massive problem for smaller operations like musical instrument gear makers

[itu]

CF is usually pretty dull looking. If a company like GR wants to use a woven CF, it is most probably used in the surface only. To make CF somewhat cheaper, it can be combined with GF (glass). CF is always black, and white GF can be tinted (CF can be tinted, too, but the results are quite faint).

 

Like others have mentioned, stiff, and damping, and light material would be optimal, but usually two out of these three is possible.

 

Brackets in a plywood cabinet stiffen the system and prevent ringing. With suitable wool/fabric the internal effects can be tamed. Functional bracing requires R&D, and more complex production, which are not cheap.

 

If a box is too soft, the lowest response will be sacrificed. In practise the box "looks smaller" in volume from the speaker's point of view (try putting a speaker to a cardboard box). Therefore the low end rises. Stiffness is important.

 

The low end requires power.

1) If you want to raise power a lot, you need elements that can handle that power: the end result is seen in weight and size.

2) If those elements have good efficiency, and can handle lots of power, fewer are needed, and the system weighs less.

3) If the box is small (and therefore light), lowest end eats watts a lot, because the efficiency of the box will drop. You cannot have a very low end, and very good efficiency in a small box.

4) A big box made of light and soft material is relatively light, but does not offer support for low frequencies without special structures (like bracing). This raises costs, and weight.

 

All in all, a box made out of CF is a good idea but the material itself does not solve problems. A seasoned designer can take the best out of it, but a

- 10 lbs.

- 2 x 12"

- efficient

- 129 dB

speaker would cost a lot. Elements, and the needed air space for low end require some volume, so a cabinet cannot not be super small.

 

All in all, we still need to carry those big, and cumbersome boxes around. I love neodyme, but I still hope to see some even better solution that could produce earthshaking lows in a size and weight of a one gallon tank.

 

About the health issues: yes, resin and fibers can be really bad to your health in production, but all companies I have seen have had very modern facilities. I do not see this as a problem. A 3D printer produces nano particles, which possible long term problems we know nothing at all. You may have it installed in your bedroom.

Edited July 31 by itu

[Bill Fitzmaurice]

50 minutes ago, Chienmortbb said:

True, Airbus have been using CF wings for decades but they are extremely well braced. With corporations like Yamaha involved in loudspeaker design, as well as marine and motorcycles, you would think that CF would have been considered well before now.

It's been considered, and used, but aircraft, boat and automobile industries use so much of it that there's not much left over for cottage industries. This keeps the price high as well.

[fretmeister]

31 minutes ago, Bill Fitzmaurice said:

It's been considered, and used, but aircraft, boat and automobile industries use so much of it that there's not much left over for cottage industries. This keeps the price high as well.

 

Same as with neodymium. Aerospace industry wants as much as they can get hold of. 

[fretmeister]

1 hour ago, Mediocre Polymath said:

I'm not an informed source on this, but from what I've heard, there seems to be  growing consensus among occupational health people that CF and similar resin- or epoxy-based composites are even worse for the human body than previously thought. The kinds of precautions needed to handle them safely, and stay in compliance with the law, are probably easy enough for a massive corporation like Boeing or Airbus to do, but would represent a massive problem for smaller operations like musical instrument gear makers

 

Wasn't this rumoured to be one of the reasons why Status have stopped doing CF necks?

[Hellzero]

On their latest AeroTech iteration Gr Bass uses a sandwich panel were the two outer sides are woven CF and the inside a damping material, so an inert panel stiff enough to be glued and braced.

 

I have photos of the inside of one GR Bass AeroTech 212 slim cabinet: there is no other damping material and it works very well.

 

The downside of the inside covered with glassy woven CF is that if something like a residue of soldering tin moves and vibrates it can really drives you mad thinking there's an issue with a speaker, so beware of the bass reflex ports that can let anything very small go inside...

 

I also need to find the video where the sandwich panel is shown.

[Baloney Balderdash]

Anyone ever made a cabinet of clay, like a ceramic cabinet?

 

Beside the obvious disadvantages, I wonder how that would sound.

 

I mean apparently, according to Phil Starr, lead cabinets exists, so why not?

 

Edited July 31 by Baloney Balderdash

[tauzero]

15 hours ago, JottoSW1 said:

How light is really absolutely  required / necessary ??

 

I decided that 10kg was the maximum weight for any one item. GR Bass Cube AT800, Alto TS series 8" speakers. I think the leads bag may be getting up to 10kg.

[Bill Fitzmaurice]

2 hours ago, fretmeister said:

 

Same as with neodymium. Aerospace industry wants as much as they can get hold of. 

Most of that goes into electric motors for cars, and windmills that provide electric power to charge car batteries. The main reason for high neo pricing is most of it comes from China, which wants to corner the market on electric cars, so they raised the price on neo for export.

Quote

Anyone ever made a cabinet of clay, like a ceramic cabinet?

People have made cabinets out of everything imaginable, including concrete. But heavy materials just aren't practical, and they're not necessary. If you built balsa aircraft models as a kid you already know how to make structures that are very light weight yet very strong.

[JottoSW1]

15 hours ago, Bill Fitzmaurice said:

1. Carbon fiber is very stiff while also being very light, so it is structural. But there's a lot in the GR advertising that doesn't live up to scrutiny. They're light, yes. But as to the rest...🤥

2. Barefaced braced construction is labor intensive, which adds to the cost. So do their premium drivers. There's nothing wrong with plywood.

3. A conventional plywood enclosure uses 18mm plywood with minimal bracing, if any. Whatever the material is better results come from thinner/lighter materials with extensive bracing. It's more expensive, because of the added labor cost, but you gain the benefit of lighter weight every time you pick it up.

FWIW agreed as a dilettante/layman type person. I used to 'row crew' when tech became a thing in late 70s and wood tonewood or otherwise was on the way out. An Olympic crew got a silver medal in 8s in 'the carbon tiger' which didn't live for long as a functioning boat. Various German Chinese US Canadians now make long lived products at a cost. I know about current pre pregs and earlier honeycombs and stuff. I've even done a tidy repair on a boat called a janousek. So I excised damaged aluminium honeycomb and interior wall OK. Borrowed a pair of very expensive metal cutting shears and cut a bit. Used car glass fibre tape and ensured it would adhere. Skim what u call bondo and poorly matched aerosol. 

You and others might think I've gone on too long but I hoped you might be first respondent (cringe alert) cos you would know that I had to do a sensible repair in an emergency.  I leave things with hefty capacitors to people with excellent expertise no names no packdrill...

Last analogy coming up....

It's just that someone said something years ago about a light car called a rocket. A teeny thing with a big motorbike engine designed by a still famous ha ha ha F1 designer. It had carefully made free floating carbon fibre front mudguards, saved several grammes per side. This journalist said that as they would very likely get broken you should use aluminium 

Crikey hot topic but I'm not going to debate with anyone who pisses me off in their interactions with me if I bother to answer anyone else. Don't tell me I have all the gear and no idea either or I'll get v v tetchy and still not reply..ha ha