Dali speaker cone repair

[Scally]

I have a good pair of Dali speakers.

The rubber around the edge of the bottom cones (17cm diameter) has perished.

The speaker boxes are:
H-900mm x W-250mm x D-300mm.

They are about 15 years old.


Can they be repaired and is it worth doing?

I saw similar new Dali speakers and there were none under $2000?

[Master Splinter]

Have a look at Jaycar's website - they have rubber surrounds.

Or
http://www.speakerhospital.com.au/foam.htm
http://www.adelaidespeakers.com/speaker-repairs-upgrades.html

[Scally]

Thanks, that's great.
I will check the web site.

the Speaker Hospital is an Sydney so I can get there.

I didn't see any price guide. Do have any idea what it might cost?

[GraemeCook]

Hi Scally

For high quality speakers like Dali I would be a little wary of using generic surrounds from a discount supplier like Jaycar.

A couple of years ago I re-did the surrounds on my 1976 Tannoys with a kit from www.speakerbits (http://www.speakerbits).com in Melbourne. Tom Manning at Speakerbits also gave excellent phone advice and assurance.

Detailed instructions came with the kit and the first one took about 45 minutes, the second took about 30 minutes. The next should take less than 20 mins.

The speakers now sound like new - much more detail in the music than before the repair.

Cheers

Graeme

[rrobor]

The ones from Jaycar are as good as any other, but if you want to know what a lot of Djs use for their huge speakers its shamois leather. From new the glue strips of shamois leather around their speakers. My workshop speakers fell to pieces and thats what fixed them. Big circle of shamois, V it out for no overlap and glue it over what is still there. When dry paint the bit on the cone with aquadhere to make that hard. $2000 for speakers is for the fairies. And Tanoy had a standing order for a new Rolls Royce each year. Never made a thing, just had it rebadged.

[Zaphod]

The ones from Jaycar are as good as any other, but if you want to know what a lot of Djs use for their huge speakers its shamois leather. From new the glue strips of shamois leather around their speakers. My workshop speakers fell to pieces and thats what fixed them. Big circle of shamois, V it out for no overlap and glue it over what is still there. When dry paint the bit on the cone with aquadhere to make that hard.


Bad idea for hi fi speakers. Such a procedure alters the characteristics of the speakers. Much smarter to fit the same type of surround material as the original. In 15 years, do it all again.



$2000 for speakers is for the fairies. And Tanoy had a standing order for a new Rolls Royce each year. Never made a thing, just had it rebadged.

Incorrect. Well, I don't know about the Rolls Royce thing, but the rest is bollocks. Tannoy have been designing speakers for many decades. Like the vast majority of modern speaker manufacturers, they source their drivers and crossover components from outside. Tannoy did, once, manufacture their own drivers however.

[rrobor]

Yes perhaps I did overdo it a bit. As to Guy Fountain, he belonged to the same rotary club as my uncle, and yes he did get a new roller each year. As to speakers, I trained with 35 other blokes and the college I trained at had a distortion meter. Only one guy out of 35 could pick distorrtion below 2% the rest of us were between 4 and 6%. That was young ears, nice soft ear drums, not the tough old leather things that most men get when over 40. So spending a couple of thousand on speakers for a male over 40 is buying the kings new suit, "It looks good, Feels good, is good". (Hal Todd).
If you look at the posters speakers they will be flapping and vibrating, you have rear mixing with front and the distortion of those will be over 10% but thats not his issue, he didnt know that because he didnt hear that.

[Scally]

I have done some running around.
I COULN'T FIND MY WAY AROUND SPEAKERBITS SO GAVE UP. Caps Lock , sorry.

Jaycar didn't have the right size, Custom Audio recommended eBay and Speakerbits.

There is a local speaker specialist who said his expert will be back at work next week. I think they do the repairs so may not supply the parts.

I sent Dali an email. They suggested I get a professional to replace the surround.

If I can get the right rubber surround from the local specialist then I will try to do it myself.

The model is 4A MkII.

Thanks for the advice.

I wouldn't mind a new Roller every year.

[rrobor]

Actually to tell the honest truth Fountain was a very smart man. He had his standing order for a roller. There was a waiting list for rollers from memory it was 3 or 4 years. When some pop star wanted one they couldmt get a new one, best they could get was a well maintained year old one. So Guy Fountain sold his year old at new price. Those that have get.

[GraemeCook]

I have done some running around.
I COULN'T FIND MY WAY AROUND SPEAKERBITS SO GAVE UP. Caps Lock , sorry.
.


Here's the precise Speakerbits site pages:
www.speakerbits.com/products/speakers/speaker-cones/list-169.aspx.

If you cannot find something closer to home then you could ring Tom Manning at Speakerbits 03 9647 7000. He was very helful to me, and overnight delivery.

Cheers

Graeme

[Zaphod]

Yes perhaps I did overdo it a bit. As to Guy Fountain, he belonged to the same rotary club as my uncle, and yes he did get a new roller each year. As to speakers, I trained with 35 other blokes and the college I trained at had a distortion meter. Only one guy out of 35 could pick distorrtion below 2% the rest of us were between 4 and 6%. That was young ears, nice soft ear drums, not the tough old leather things that most men get when over 40. So spending a couple of thousand on speakers for a male over 40 is buying the kings new suit, "It looks good, Feels good, is good". (Hal Todd).


That is the most banal statement I've heard in a very long time. $2,000.00 buys a reasonable pair of speakers. $20,000.00 buys a magnificent pair of speakers. I guarantee you that anyone (even someone who is mostly deaf) will hear a difference.

Speakers are more than just how much distortion they create (or don't). Frequency response, phase response, maximum SPLs, etc, etc. In fact, the human ear is very sensitive to phase errors. Some speakers (like electrostatics) possess a superior phase response. Such performance is rarely available at low cost. Ironically, such speaker also possess low distortion (often less than 0.1%) too. And trust me: It can be audible to some people. Even people who are well beyond 50 years of age.

Lastly: I worked with a man who was 50+ years of age. He possessed very sensitive hearing. So much so, that he wore ear plugs every day. We measured his hearing and found that he could hear past 22kHz.

I suggest you pop into your local hi fi store and try listening to some high quality (say: $10k +) speakers. Then compare them to some $2k speakers.



If you look at the posters speakers they will be flapping and vibrating, you have rear mixing with front and the distortion of those will be over 10% but thats not his issue, he didnt know that because he didnt hear that.

That is a normal thing. Speakers deteriorate slowly. People often don't notice the problems 'till they become really bad.

[Scally]

Old ears or not I am taking the speakers to the local HI specialist tomorrow.

He said it will cost $165.
It sounds a lot to glue on two pieces of foam but I figured it would be safer to let the expert have a go.

He sounded like he knew what he was talking about and would make sure that the job was done right.

Thanks everyone for the advice and discussion.

I should have them back on the weekend so I will be able to see how they sound.

[Zaphod]

Old ears or not I am taking the speakers to the local HI specialist tomorrow.

He said it will cost $165.
It sounds a lot to glue on two pieces of foam but I figured it would be safer to let the expert have a go.


It's a little on the high side, but if the surrounds are unique, then that can add to the cost. Some JBL surrounds cost in excess of $120.00 each! That's without the labour to fit.

BTW: To re-surround a speaker PROPERLY, there is much more to it than just gluing the surrounds on. The speaker needs to be caefully adjusted using test equipment to ensure that perfec centring has been achieved.



He sounded like he knew what he was talking about and would make sure that the job was done right.

Thanks everyone for the advice and discussion.

I should have them back on the weekend so I will be able to see how they sound.

Good luck.

[GraemeCook]

$165 sounds like a pretty fair price - one hour of a technicians time plus OEM-quality surround (not discount junk) glue and dope plus commercial risk. Good value for money.

Zaphod is right when he says that the surrounds have to be carefully aligned, but I would not describe the aligning shims as "equipment".

I think you will be surprised as to how much better the speakers will sound once re-surrounded.

Cheers

Graeme

[rrobor]

Anyone ovr the age of 40 who spends $20K on speakers has too much money. There are always exceptions to every rule but a handy test is look at your eyes. If you need reading glasses because it seems your arms are not long enough, its due to toughning of part of your eye. If that happens, your ears are tougher as well. Up to the age of 30 I could walk into a house and tell if a TV was on, thats 15.625KHz. At 50 I was less certain if a TV was working and at about 55 that was gone.
I can tell on an audio unit what age the person is. Just look at tone settings. A kid has all bass low
treble. As you age bass goes down treble goes up. When playing music you rely on how good the recording is, how good your amplifier is and so on. $20K on speakers is the kings new suit, if it makes you happy, then OK. Many years ago there was a guy in the UK named Hutson who designed electronics. His wife wrote that his favourite speakers were modified toilet pans, Im sure Fowler would love selling those for 10K.

[Scally]

The guys were a bit concerned when they saw the speakers.
They told me that there could be damage to the coils/drivers.

Anyway apparently they were fine and they replaced the surround and tested everything out.

I hooked them up and they sound as good as new.

$165.00 sounds like a lot of money for a couple of pieces of foam but I know that materials are a small part of the cost.
I think it is a reasonable cost for a couple of hours by an expert and I have the confidence that the work was done properly.

$20k or $40k is a bit steep for me but I am sure they would be fantastic speakers.
My repaired $2k speakers make enough noise for me and I reckon that I can hear a lot more music with them now.

A friend came around on the weekend and took my didge into the bathroom to play. He said that it is the best room in a house to play them.
Next time I will ask him if he want to play in the WC.

Cheers.

[soundman]

I have only done a few, recones/refoams (unlike some of my mates who have done hundreds)... but $165 fo doing what would be 4 drivers.....and dismantle and reassemble boxes........seems quite reasonable.

There are several methods.....some use shims some eye them up.

this is what is involved.

remove the drivers from the boxes

from those available select a surround that is close to original and a matching dust cap

remove the cone from the frame (some don't)

clean up the frame (this takes time)

remove the dust cap (some don't)

clean up the cone and the spider (this takes time and a carefull touch)

fit the surround to the cone (this requires a straight eye and plenty of care)

wait for the glue to go off

trial fit the cone in the frame and cut shims to centralise the voice coil.

remove the cone and apply the glue to the spider and the surround

apply the glue to the frame

depending on the materials ( and the method) a different glue may be required for the spider and the surround......(no solvent bassed glue if it is a rubber or foam surround)

slip the cone into the frame with the shims fitted.....do not allow the glued parts to contact.

with the cone straight cental in the shims....slide the cone into place and mate up the spider and the surround with the frame.

I usualy use a solvent bassed glue on the spider and a specific water bassed glue for the surround.....because you can stick the spider down and it stays and you can then finesse the surround.

examine the speaker from all directions to check that it is straight.

set it aside and hope.

when glue is set......check speaker travel.....gently by hand.....then with amplifier and LF oscilator.........all good... relief............not good.....start again.

fit relacement dust cap and dope surround as and if required.

fit cardboard rim pieces if required

wait for it to dry.

test again......glue dribbles from the dust cap can ruin it all.

refit to boxes..and re test.

explain to customer why a couple of bits of foam cost so much.

seriously.......anything less than $50 a driver for a proper job is more than reasonable.

personaly...I do not believe it is possible to do a proper job without removing the cone and I'll be b###d if I can see how anybody could get a voice coil properly straight and central with out shims.

this is how the pro recones are done.


OH.... anybody who thinks they can make a proper surround out of anything is kidding themselves.......particularly if it is a high power pro audio application.

I do not know of any manufacturer who has made a production speaker with a leather surround........in the older times ( and still) various cloth or papers were used as surrounds.
leather is too unrelaible and inconsistent.

in older times both tannoy and warefedale used to make their speakers from scratch....including their cones and surrounds.

in more recent times all manufacturers either source components externaly or let out the whole job..........

cheers

[Scally]

Thanks for the explanation Soundman.

I remember the guy mentioning some of those steps. He has a good reputation so I expect that he did a professional job.

[Buzza]

Toilet bowls, "The Original Ceramic Speakers". :D

[GraemeCook]

I fully endorse the thoroughly professional explanation by Soundman, except that he omitted one crucial step.

* Before replacing driver in box

* * Paint "coating goo" on the newly installed surrounds.
* * Apply a second coat of "coating goo".

The "coating goo" is as described in my Tannoy surround kit and is a thickish white liquid that dries clear. Its purpose is to stiffen and deaden the surround to help minimise colouration.

Cheers

Graeme

[Zaphod]

I fully endorse the thoroughly professional explanation by Soundman, except that he omitted one crucial step.

* Before replacing driver in box

* * Paint "coating goo" on the newly installed surrounds.
* * Apply a second coat of "coating goo".

The "coating goo" is as described in my Tannoy surround kit and is a thickish white liquid that dries clear. Its purpose is to stiffen and deaden the surround to help minimise colouration.

Cheers

Graeme

Not a smart idea, unless the designer has taken the addition of such a product into account with the initial design. Bass reflex enclosures are particularly sensitive to speaker characteristics.

[GraemeCook]

Not a smart idea, unless the designer has taken the addition of such a product into account with the initial design. Bass reflex enclosures are particularly sensitive to speaker characteristics.


Sorry Zaphod, but I think Tannoy might be a little smarter and more knowledgeable on their speakers than you.

Cheers

Graeme

[soundman]

I did mention the doping the surround if required.

quite a few manufacturers are using some sort of dope on or in the surrounds.

the idea is that it dampens standing waves from running across the cone and bouncing off the frame and back onto the cone.....suposedly reduces harmonic distortion and peaky top end response in the cone.
Its pressence needs to be accounted for and it would influence the mass of the cone, stifness and damping of the cone

I did some EV drivers recently and the original drivers had one of the "V"s in the surround filled with dope.

if the original has it you do it if not you dont.

quite a lot of what you do depends on how the parts come to you......at one time most recone kits came assembled......cone mounted to voice coil, with surround and spider attached and all treatments already done....all you did was shim it up and glue it down.....bung on the dust cap......a fast operator could do a 15" recone in 20-30 minutes and slap it back in the box during interval......I can remember helping a bloke replace a blown driver in a rear loaded box while a show was running......it was not uncommon in the days of rock and roll to do recones by the side of stage.

then some of the manufacturers tried to save cost ...shipping was a biggie.....they could ship 10 recone kits for the price of one if they shipped unassembled.....in that case you had to do all the treatments as well as assembling the kit.

if you are using generic surrounds they will come untreated......so you have to eye up the treatment as well as the closest surround.

In the past most pro recones were done with solvent bassed contact type cement....most recones came with a tube of a bostik product........black spray can paint was mixed with the supplied glue when fitting dust caps and for doping cones and surrounds.
Many of the cloth surrounds came untreated and required some form of dope....some used PVA.

with the advent of foam and rubber surrounds solvent bassed glues have gone out of favor........many of the surround failures have been due to solvent bassed glues used in original manufacture.

The water bassed glue, I get from my supplier is used for the dope as well as fixing the surrounds.......it is nowhere near as fast as the solvent bassed glues.........but if handled well is a great product.

Its actual composition has slipped my mind..... but it is an AV syntec product that is only available in 20L drums........EVA rings a bell.....it is much more flexible than PVA.
comes white and dries water clear and a little rubbery.

cheers

[soundman]

most pro audio drivers.....like the tannoy, are quite stiffly suspended and the pro audio designs seem tolerate variation much better than the HIFI items particularly those with small drivers.

cheers

[Zaphod]

Sorry Zaphod, but I think Tannoy might be a little smarter and more knowledgeable on their speakers than you.

Cheers

Graeme

THEIR speakers, being the operative words. We're not discussing Tannoy speakers. We're discussing Dali speakers. Dali do not use any goop on their surrounds. Therefore, goop should never be applied to the replacement surrounds.

[soundman]

yeh lets not get all bitter and twisted about this.

In general terms you do as was done.

But I will say that there is an eliment that seems to think that speakers are a high precision article......nup........there is quite a lot of variation from one driver to another ( in comparison to other enginered items) tolerances are quite wide.........in engineering terms a speaker is a lump of paper glued to a motor........lets not kid ourselves...... ..and i have seen and heard plenty of speakers that have been......um....er.....fiddled.........and lets face it.....it isnt a life and death issue.

so whats the worst that can happen..........OH NO...:oo::oo:..he doped the surround... we are all going to die.

cheers

[Zaphod]

yeh lets not get all bitter and twisted about this.

In general terms you do as was done.

But I will say that there is an eliment that seems to think that speakers are a high precision article......nup........there is quite a lot of variation from one driver to another ( in comparison to other enginered items) tolerances are quite wide


I measure speakers (drivers) as part of my professional life, for several companies. I always request that I be supplied at least 4 samples of each driver. One company supplied me with a range of drivers from their supplier in China. The drivers were terrible. Not that their absolute performance was bad (though it was), but that the 4 drivers had critical measured characteristics that were as much as 30% different. Contrast that with typical European drivers which easily exceed 5% tolerance from driver to driver. The same company then provided me with some new drivers, sourced from another company. These were easily as good as anything I've measured from the best European manufacturers. If they are provided with sufficient encouragement, the Chinese can turn out a quality product.

The upshot is this: By mucking about with a driver, by applying goop to the surround, one risks impairing the performance of the driver by a considerable amount. I know this from personal experience. Goop is not a panacea. It should be used when the manufacturer suggests it. It should not be used when the manufacturer does not suggest it. Many years ago, I figured that I would start using butyl rubber surrounds for clients' speakers, as the butyl rubber surrounds are far superior to the plastic ones used by many manufacturers. That idea quickly came unstuck, when several clients complained about the sound quality. The butyl rubber has radically different characteristics to the foam plastic ones. In EXACTLY the same way that adding goop to the surround will have. My desire to provide a superior product to my clients ended up back-firing on my big time. Back in the late 1990s, when I acquired some sophisticated measurement equipment, I measured the drivers and understood why my clients complained. The different surround materials impacted on the measured (and audible) performance of the drivers.




.........in engineering terms a speaker is a lump of paper glued to a motor........lets not kid ourselves...... ..and i have seen and heard plenty of speakers that have been......um....er.....fiddled.........and lets face it.....it isnt a life and death issue.


No one said it was. Bad advice, however, is just that: Bad advice.



so whats the worst that can happen..........OH NO...:oo::oo:..he doped the surround... we are all going to die.

cheers

The worst that can occur is that the speakers can never be returned to their original performance capability and the owner can be dissappointed for a very long time.

[soundman]

The worst that can occur is that the speakers can never be returned to their original performance capability and the owner can be dissappointed for a very long time.

Lets hope they never have anything serious to worry about:no:.

cheers