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Speaker drive unit questions

supercapman

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Jul 19, 2005
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Chris
Although I am over the moon with the sound of my meadowlark Shearwaters, I had noticed that something has been spilt over one of the Scan-speak bass drive units (Coffee?), visually it's just noticable, acoustically cannot hear anything wrong with it.Normally I would send them back to the shop but they are like rocking horse shit on the second hand market.

My first question is this; should i replace the pair? These speakers have a bit of a name for running in, so my plan was to buy/borrow a dirt cheap receiver along with some speaker cable,crocodile clips and have them running in for a month or two before I put them in the cabinets.

Second question; is it safe to wire bass units direct to an amp/receiver with no crossover or tweeters?

Hope this makes sense,

Cheers SCM.

 

yoda900

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Sep 20, 2005
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  1. Yes
DO NOT overdrive them as you wont hear a great deal but could damaging them.
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Put them face to face and wire them out of phase to noise cancel them.

Perhaps Mosfet can advise more .

 

mosfet

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is it safe to wire bass units direct to an amp/receiver with no crossover or tweeters?
Provided you don’t thrash the woofers too much yes you can get away with this. Still why would you want too? explain further..

Tweeters without a high pass filter – absolutely not unless you want to bugger ‘em good and proper.

and have them running in for a month or two before I put them in the cabinets.
Completely unnecessary. 20 to 40 hours tops for a woofer. There are ways you can speed up this process if you wish.

 
E

earl of sodbury

Guest
Chris, if you bought them from a dealer, then they should make reparation - I'd say some new drivers would be in order, as you bought them believing them to be uncompromised: coffee spills do not constitute fair wear and tear IMHO...

hope you get it sorted one way or the other, cheers, Paul

 

mosfet

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Re-read the post now (duh!).

First recourse would be to go back to the dealer as earl and Dave suggest.

If this doesn’t work then a replacement woofer would be best run-in connected in series with a 1.0mH inductor (or slightly higher) with some Prodigy or similar left on repeat play for about 20 hours.

To speed up the process a little you could create a 60 minute WAV file of a 200Hz sine signal - with a WAV editor like Audacity - burn this to a CD and leave on repeat play for about 12 hours.

 

supercapman

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Don't want to get in a wrangle with the dealer as it's been over a month now and since been in contact with them to say all is OK
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, thanks for the tech. advice will look into that.

 

Davewhityetagain

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Jul 24, 2005
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as Tony says or it will sound very strange and even if with odds of 10.000 to one they did sound the same you would get into a right state sitting there your ears would play all sorts of tricks on you would do your head in
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only ever seen someone change just one of a pair once...... not a nice site
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mosfet

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Why a pair Tony?

Once the new woofer has run-in it’s electrical parameters (notably resonant frequency) will be the same as the existing driver - allowing of course for differences in engineering tolerance that would exist between any two Scan Speak drivers of the same type.

 
M

Mr Coherent

Guest
Not going to disagree with the theroy Richard.

In practice however, its a bit like replacing one worn shocker, the other has years of wear (remember mechanical wear too) IMO it just doesn't sound the same. uneven balance.

Last week, I damaged a driver on a pair of speakers I've been working on, (a total pig to remove them), scan speak also this time mids, I replaced BOTH units cost to me £356
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I would fabircate a crude x/over to remove all the freqs above 2/2.5k which is where the x/over is at on the Shearwaters I believe.

Still not sure why you wish to change it Chris?

Unless the voice coil/ suspension or cone is dmamaged I would leave well alone

The drivers themselves won't take that long, as the caps and x/over have all ready been run in. T.

 

Davewhityetagain

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Jul 24, 2005
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it would take a lot of liquid to damage the fabric of the speakers I have seen all sorts of liquids on drivers from beer spray to three raw eggs only on one occassion had the driver been really damaged

your reports on listening to the speakers has been very positive if you had come along and said they sounded like a bag of shit it would be fit a pair of new drivers

my own thoughts are the liquid in no way affects the sound quality at ALL

but you have seen the stain and its bugging you

let go of the stain save your money for cds

 

supercapman

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Jul 19, 2005
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Right, just took out both drive units, I presumed a spillage had occured as one drive unit looked shinier and the texture was harder than the other.But on examination one driver at some stage has been replaced as their was a wad of blue tak stuck to the back of it :Upset:
angry_smile.gif.8c0f636dd68eb7da5c2577e161ee9e27.gif
looks like i'm gonna get some new drivers.

Anyone know if these differ to mine in any way? : http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=5826813237

 

jon

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Jul 20, 2005
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  1. No
Right, just took out both drive units, I presumed a spillage had occured as one drive unit looked shinier and the texture was harder than the other.But on examination one driver at some stage has been replaced as their was a wad of blue tak stuck to the back of it :Upset:
angry_smile.gif.8c0f636dd68eb7da5c2577e161ee9e27.gif
looks like i'm gonna get some new drivers.
Sound kind-of dodgy - you might want to have a word with the dealer
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Still, if you can't get the dealer to fix it and can't hear the difference between drivers, there's a definite argument for leaving well enough along until something breaks
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Jon

 

Kiang

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Jul 21, 2005
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I am not suggesting you do this as it is an expensive and otherwise intact driver you have there.

With cheaper drivers in the past I have used a spray of a very dilute solution of "gum arabica" in distilled water. A trick learned from painting with acrylic paints. You have to mask off the periphery of the driver where the ridges start.

If you do go down the route of discarding the drivers - worth a try.

If sonically there is no problem - I would leave it alone (things are usually more lucid the next morning after a cup of coffee) . Just postpone the decision for now.

 

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