Replacing driver screws with brass screws

Tom, huh? What are you talking about?

I have been one of Tom’s customer’s for well over 10 years, and yes jetter, he is one of the "better minds" that I was referring to. Starsound Technologies...look them up.

Jitter look up the transverse shear velocity of the metals you mentioned..add to that list aluminum and all their many cousins. Shear velocity and their polarities are a big key to how things sound and why they sound so different. Tom

Jetter where did that last post go?

Will we ever find out who, in fact, hired who and what really happened in that saga between Robert and Michael Green? We have been kept in suspense for two years.

Sorry guys, I deleted my last post. I didn’t want to publish that in my world it is not conceivable that anyone could or even would want (to be ? enough) to hear the difference in sound of different metals holding down a speaker. You called me out on it, so there it is.

"...the difference in sound of different metals..."

No love for wood?

Mr. Glup has questioned several times the appropriateness of using wood screws to secure speaker drivers to the cabinets.  As well as the sonics of using different wood variety screws.  His inquiries have not been heard or addressed? 

I had a few more.

Different, let them be metals, screws on, for example, wooden, aluminum, granite, etc. enclosures. It seems like those interactions might prevent that only one type, brass in this case, is "the one". In short, if different screw metal matters, why wouldn’t different materials the screw is attached to matter even more in this story?

Then, are there screws on electrostatic speakers? If yes, do changes in their material also matter for the sound?

I know that title is "Brass screws", but these questions are not that removed from the discussion. They are only a developmental step above "brass or no brass".

I know what you are thinking. "No bras(s)".

It is not necessarily the brass vs ferromagnetic steel screws but screws better bonding speaker frames to the cabinet.

@andrei_nz,

’I guess in theory it did - as in everything makes a difference, not that I heard a difference. Did it improve the sound? Again, I do not know - it was inaudible to me.’


In theory anything could make a theoretical sonic difference - the power supply, the room temperature, the heat in the voice coil, the type of solder used, the finish of the cabinets, the types of connectors used, or ... maybe even a butterfly flapping its wings in the Brazilian rainforest etc.

However, since we’re only human, perhaps it’s best to leave imagination behind for once and to stick to those differences that we can consistently identify, time and time again, with or without visual evidence.

Life is finite, and so is our hearing. So why keep wasting time experimenting in ways that could make things a lot worse?

Why risk stripping of the cabinet screw thread, or upsetting the manufacturers desired torque?

Because someone online who enjoys trying out tweaks recommends brass screws?

Is anyone surprised that the respected designer John Dunlavy laughed when it was suggested to him?

Is it really very likely that some amateur online knows more than highly qualified and experienced designers?

Are you really so willing to gamble on that likelihood?

One slip of the screwdriver and...

One slip of the screwdriver and...
Yes, this is a serious consideration.

Why risk stripping of the cabinet screw thread, or upsetting the manufacturers desired torque? Yes, this is a consideration.

It is something that needs to be thought about and considered, even though I do believe based upon personal experience that different materials in baffle screws (materials have differing Young's Modulus) perform differently, it is to be done with caution.

Is it really very likely that some amateur online knows more than highly qualified and experienced designers? It is actually being used and was used by designers in the past and in the present. This isn’t new, it’s older technology that’s being newly presented here.

If someone isn’t going to take the time to research it properly, and purchase appropriate tools and fasteners to correctly implement this technology - I totally agree with CD318 - just don’t.

glupson, sorry to spoil your fun, but after previous comments you’ve made, I don’t for one second think you’re serious about wooden screws.

But by heck if you are serious, go ahead, I’ll read your review.

I still remember my primary school teacher who’d emptied out a mercury thermometer for science class. I wanted to pick up the mercury and he forbid it, telling me it was actually dangerous to touch. I remember thinking to myself, is he just saying that so I won’t touch it, or is it true? and he’s actually protecting me.

I recognize that I can be arrogant and proud as much as anyone. I remember being asked what quality of water is the most beneficial to supporting life?? I gave all the qualities of water I could think of down the list I’d learnt... Kept getting, no that’s not it... Then I was told the answer, and as soon as I heard it, it dawned on me that it made perfect sense..
It’s waters solubility, to transfer oxygen, proteins, glucose, mineral ions, hormones, carbon dioxide, waste byproducts...

It’s people like Tom who provide products and information that expose others to technologies we’d normally never hear about.

Thanks Roxy54, a good controversial thread!

Took a beatin in the early 2000's and kept on kickin..Robert and I..Thanks for the good speak. Always looking forward for a better way.  Cryptic I am about some things I am working on and get excited about somethings that bring false hope but those hopes sometimes lead to something wonderful as I am listening too now. The toughest thing is to be able to explain why it works and how it could further improve the event. Let you know when I can. Tom

Ricki,
I actually should have known that it would be controversial, but that wasn't the intent. It was just one of those things that I had been meaning to try for quite a few years, and I was excited to share the unexpected positive results. 

So what you're saying, to even talk about brass screws takes brass balls. The man's a poet, didn't know it. As Will Shakespeare once said, This s**t writes itself!"

Well, there’s three choices: try it, talk about it, or just forget about it. All valid.

Ok, "My turn"!
And please feel free to look this up!
There are several reasons replacing the screws with "Brass" will change the sound of your system. But it needs to be of the "Cast" variety.
There is actually, a single "published" study by a well known and very well regarded "Ivy League" university as well as many others currently, "Un-published" and still, um classified. "I know of at least fifteen of these".
The un-classified study is not hard to find online. Just ask the right question of your browser!
And ALL of them were commissioned by the federal government with most but not all paid for by military research entities. Also they were all offered, and completed within the same 12 year period. They were to study and classify all known alloys with the goal of ascertaining the effects on electromagnetic fields when different alloys are applied to said fields. They found some odd things. One of which is that "Cast Brass" works as a mid-range frequency, resonance and free harmonic filter.
It's been awhile but I believe the range was roughly 1.4Khz- to a little over 5Khz. The brass could also be used as a type of particle boundary. They can also help stabilize a field if used in a certain fashion. And since the voice coil works how it does this applies. No snake oil here.
I use cast brass machined screws to secure the transducers in certain bass columns I build with "Storm nuts", "I think that what some call them".
On the inside of the cabinet which are stainless steel with the (teeth), biting into the cabinets wood. I use fairly large screws and they are torqued to spec. so that the threads are not damaged.
If anyone really wants but cannot find that study I talked about above? And would like more info. I do have it here in hard-cover, book form. "Somewhere". I would just have to dig it out.

Color me impressed!

My question about wooden screws is very real. It is just another material. If brass, and we have no idea what composition we are even talking about, is allegedly making a difference then any material could be making a difference.

Same goes for "brass on the speaker". Different enclosure materials, many physical variables (location, number of screws, size of the screw, etc.). It is a nice start to think "brass", but it becomes a little suspicious when with all the possibilities "brass" is the answer and any development of that question becomes "not serious".

Is it maybe zinc in brass we are really looking for? Maybe copper? Or maybe zelkova?

Also, there is a mention of "tightened to spec" earlier. Do manufacturers publish those specifications?

I'm certainly not qualified to rule out wood or any other metal. If I hadn't read about brass years ago, I would never have considered it.
I do wonder about wood screws though...wouldn't they be very fragile and hard to manufacture?

I’m not changing my speaker screws. If Peter says it’s of no effect- I am 100% confident in what he says. In years on these boards there is in my opinion only one or two other people whose analysis and conclusions are consistently rock solid. Peter is in the top 3 of “knows his stuff” 

I would think Japanese zelkova for monitors.....

Personally, I would use ironwood.

There are several types of brass most have 59 to 63 % copper and up to 3% lead the balance being zinc. I use 3 different brass types in my endpin designs for cello, though predominantly just 1 type. The differences are audible. I also use rare earth materials in conjunction with the brass and it is these materials that make my endpins more or less reactive to touch and vibration. Specific mix ratios of materials are part of the blend.

Most metric sized brass is c385. Metric sized threads are what holds most domes in place to a tweeter bezel..These are the closest screws to the moving coil and will disturb the flux field of the moving coil if they are steel..which they always are in my experience. You should definitely replace these with non ferrous fasteners..brass is what I know.  Brass has between 35 and 70 % slower shear velocity than most commonly used metals.
Low shear metals sound the best in my opinion..other than lead and tin.
There is a very audible difference between using a small steel set screw and one of brass within my endpins. The steel screws the whole sonic balance off and required a total rebuild. Tom
.


 

There is a Audiogon member who replaced all of the steel fasteners on his PBN speakers with brass.  He has them within a Star Sound Energy Room. Tom

Cast copper is used in both sets of speakers in my system page, in fact the paint on my smaller pair was matched to the copper screws!

 My Focus speakers arrived by freight with very loose screws/drivers.  The bass was not right.  I tightened the screws where I thought they were tight, but not overtightened.  No problems with loose drivers or floppy bass since then (I did recheck them after last years home move).   I never had a problem with loose screws on my Signature IIIs.  I moved those locally.  Speakers (as well as other equipment) get jostled quite a bit in freight transport.

"Glupson"
Brass machine screws, "Or any other type",  don't need any info from the manufacturer to give you "any" given specs. The geometry of the part "Screw", does that for you. They are standardized globally at this point. You just need to know the alloy and standard used, "Like S.A.E. for instance", which should be on the packaging even if coded. All with the exception of real oddities are in any machinist handbook. 
Also the studies do call out different alloys of all commonly used materials as applicable. And zinc was one of the metals as well as everything else used today. Standard or forged brass showed no filtering effects. 
Is "Brass" the answer? NO!
Just another piece of the puzzle to play with that we have limited knowledge of and about.
But I keep wondering about the "exact" point at which the "Electrical expression of the waveform coalesces into that waveform. "Which should be instantaneous". And exterior forms of energy affecting the launch. If you can clean the area up as far as stray particles and stabilize the fields a little you could also retard phasing I think. But I think it's beyond the "Classical" physics modeling of field theory and well into....
    I'll be quiet now.......

You know you want to say it...

I don't know who Peter is, and I would not suggest you change your screws, beacause you don't want to.

However I will attest that is it my personal experience that they do change the overall sound (despite differing opinions as to why), and the fact that experience despite different theories seem to all corroborate this should be an indication of something.

@zavato
I went to see your system page, first thank you for sharing it, many do not.
And it looks pretty darned neat, evidently you've put in a lot of time and investment. I am sure you enjoy your music sir.

rixthetrick,

’If someone isn’t going to take the time to research it properly, and purchase appropriate tools and fasteners to correctly implement this technology - I totally agree with CD318 - just don’t.’



Yes, it just isn’t worth it.

As I mentioned earlier, and shown in the link to the excellent Siegfried Linkwitz site there are other ways of attaching the driver to the cabinet other than just screws.

If one was in the experimental mode (and not particularly attached to their speakers) they could try the method used previously by the likes of KEF and the BBC.

In this case the driver is attached to the back of the speaker cabinet by its magnet whilst the front of the driver is hardly making any contact with the baffle.

As you can see in his driver mounting resonances diagram, out of the 3 illustrated methods the least resonances occur with the rear magnet attached method. It’s tricky to implement but it sure looks like an improvement. It’s also interesting that Linkwitz might have looked at this issue as far back as November 1986 (or maybe someone else had going by the date pencilled in the diagram.).

My previous speakers used both wood screws and a soft brace behind the magnet for stability.

Some manufacturers do go to some trouble to avoid driver excited resonances in the baffle.

One popular method is to use a sub-baffle and screw the driver in from behind.

Some might to prefer using grommets.

Certainly worth considering for those brave souls who want to build their own.

https://www.linkwitzlab.com/frontiers_2.htm#N

We have a resonance tuning method that can be performed from the outside back of our cast cabinets. Never tried it on mdf or the like. Couple of degrees and you get a different out come.Tighter  slightly faster and maybe thinner..looser a little warmer and full. Been doing this since 2003. Installed the new Purifi driver just incredible now I need to install the new resonance tuner.  Tom

We do the same with an internal crossover mounted on our points and the tuned externally like the woofer. Big difference there as well. Cant do that on springs or such musical deletion devices. Tom

The only Peter I can think of is Belt.

Peter of PBN speakers and electronics seems most likely. Tom

Peter is owner of PBN Audio. He is very knowledgeable. He builds everything from speakers to amplifiers. Not too many people in this industry that knows more than him.

359/379 Peterbilt, aluminum nose. A true classic. I used to be in charge of 118 359s, and 26, 379s.. That puts a date on me for sure.. All Cummins power. 

Then I went HEAVY duty..

Regards

That was some non sequitur oldhvymec.

@cd318 - whatever does the job the best, thanks for posting.

"The only Peter I can think of is Belt."

My first thought was...Pan.

@cd318

My previous speakers used both wood screws and a soft brace behind the magnet for stability.

That’s got nothing to do with glupson’s screws made of wood idea, right?

And yeah the idea of having a flexible gasket and mounting the driver from the back isn’t used (at least not commonly so), and it seems like a pretty good idea to me.

This article also could be construed to validate that (which I was told by my employer, a loudspeaker designer for at least three decades) he uses copper screws to damp the vibrational interactions with the speaker basket and the baffle. This has been my understanding as to why the different material can act like a spring (here we go again) by absorbing the kenetic energy of the driver. It was explained to me, that he chose copper because it is softer, but more importantly that copper can convert kenetic energy into heat, being another property of copper.

Regardless, the article you posted cd318 shows grounds for decoupling the driver basket from the baffle - however is this commonly used today?
Or used at all?

It seems the second method (B) was used by my former employer, with positive results, however the rubber grommet was replaced with a copper ring set into the baffle and copper screws to retain the driver. Obviously not a cost effective upgrade.

cd318 - thanks for sharing that link

Not my field but shear velocity in metals is basically the speed of ultrasonic pulses in that metal, or at least its presented that way.  Someone correct me if im wrong.  I think tubing guys care and maybe others like non destructive testing wonks?  Given that the units for most metals is near a 0.1 inch/10^-6 seconds,  would that not imply that we are up in the mHz with this?  no comment on the topic but it seems like the propagation delta for different metals, say a .1 to a .12 is pretty small?

@rixthetrick,

’That’s got nothing to do with glupson’s screws made of wood idea, right?’


I’m guessing that the difficulty of obtaining such screws would limit the likelihood of designers wishing to experiment with wood screws.

In practical terms steel screws are fairly universal, easy to implement, and are cost effective. Whether they are sufficient enough is down to the designer.

Let’s not forget that the loudspeaker market is an extremely competitive one, with literally hundreds of different companies with models to sell.

So is it not fair to assume that something as simple to implement as type of metal used, steel or brass, for the screws would have been considered in most cases?

We know that some major designers consider the choice of screw metal irrelevant.

Do we know of any that don’t?


As glupson asked earlier,

’Also, there is a mention of "tightened to spec" earlier. Do manufacturers publish those specifications?’

As far as I know they don’t. I know Harbeth suggest finger tight (up til resistance) but are we now suggesting that manufacturers should publish torque figures?

If so, should it be our responsibility to maintain that recommended torque ourselves? Or the dealers?

Is fleschler’s case with his Focus speakers which arrived by freight with very loose screws/drivers a one-off?

Do Focus Audio know about this, and what the implications for them might be?

What do Wilson, Magico, Tannoy, Zu, JBL, Revel, B&W, ATC, PMC, Vivid, Spendor, Sonus Faber etc have to say on this issue?

Years ago people used to hot rod and modify their cars, but now in the computer age, this no longer seems to be popular.

Doesn’t this also apply to computer designed loudspeakers?

On the other hand I’m happy to accept that some, possibly only a few, like yourself have been able to get good results through careful experimenting.

You know sometimes, getting a little carried away, I almost wish that loudspeaker design was something I had considered back in school. But then I start to consider all of the technical difficulties and then I have to bring that particular pipe dream to a conclusion.

cd318,
Amusing post. What does it really matter who thinks what when it is relatively simple to just try it yourself and see what YOU think?

In theory, is there a number of screws that would matter?

For example.

A driver is attached wth 4 iron screws and we change them tu brass of some kind. There is a difference in sound. Let’s say that difference on some imaginary scale would be 2.

Next driver is attached with 8 screws that we change from iron to brass just like in the first speaker. Would the difference now be, let’s say, 4?

Would there be a certain treshold number of screws under which after changing from iron to brass the difference in sound would not be perceptible?

glupson, I personally have no experience with the specifics of that which you’re asking. Perhaps if your real intent is to discover these answers for yourself, which anyone trying to answer would most certainly be speculating. With perhaps the exception of Tom theaudiotweak - who has a business that does this kind of R&D.

Perhaps, seeing as you’re inquisitive and creative enough to come up with such questions, you could compare and report your findings to us?

I am happy to read your results after testing some of your theories and own questions :-) Do you think you could make wooden screws? What wood would you use? What method of turning the thread would you employ? What would you most likely use as your thread size? Metric or Imperial?
What made you think of using wood as a material for s screw?

Before even considering the efficacy of wood in this application, I wonder if anyone thinks that it's possible to make screws of wood; any species of wood.