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Grill on or off ?
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clubsport911
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Location: Cheltenham, UK

PostPosted: Wed Oct 17, 2012 11:31 pm    Post subject: Grill on or off ? Reply with quote

How much effort did KEF put into researching whether the grills add or subtract to the sound ?

Is the hf "smoothed" or masked by the materials ? Which material is best (foam ? Cloth ?)

Or indeed, should the grills be left in the packing box for the best sound ?(prying digits notwithstanding ).

How do you listen ?
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proffski
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PostPosted: Thu Oct 18, 2012 10:19 am    Post subject: Re: Grill on or off ? Reply with quote

Some friends have a complete set of MA Golds for their AV setup.
One day they had visitors with a young child.
Whilst they were aving drinks and snacks outside the young chap went and pushed all those lovely gold tweeter domes in for them, all five!
They leave the grilles on now...

Play some white noise thrugh your system, with your eyes closed get somebody to place grille material or grille in front of MF/HF units and try and hear the difference. Remember you will be dealing with absorption and possibly diffraction.
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clubsport911
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PostPosted: Thu Oct 18, 2012 12:31 pm    Post subject: Reply with quote

Shreek ! ... that would hurt me muchly. I like grills (clean.. hides the technology and "safe") and on the other hand... I dislike grills (bland, hides the technology.

I've left the fronts off my 105/3's and all the folks that have seen them like them (so do I Cool ) but thinking of your examples made me realise that with christmas on the way and a lot of young visitors coming around the house... perhaps I do need to put up an electric fence around the system !

The only tests I saw, were with grill off.... I have no idea (hence the OP) what efforts KEF made to make them acoustically transparent or indeed designed as part of the overall performance.

Thoughts welcome.
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proffski
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PostPosted: Thu Oct 18, 2012 1:36 pm    Post subject: Reply with quote

Forget the electric fence, 500 joules of stored energy should do the trick.

As far as the grilles you could measure it, then listen and if you hear no difference? Shocked
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speakerguru
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PostPosted: Thu Oct 18, 2012 2:37 pm    Post subject: Re: Grill on or off ? Reply with quote

proffski wrote:

Play some white noise thrugh your system, with your eyes closed get somebody to place grille material or grille in front of MF/HF units and try and hear the difference.

+1 on that (except I would use pink noise)
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proffski
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PostPosted: Thu Oct 18, 2012 5:09 pm    Post subject: Re: Grill on or off ? Reply with quote

I did momentarily ponder, but I guess that I had a blonde moment, I therefore concur! Smile
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clubsport911
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PostPosted: Fri Oct 19, 2012 1:20 pm    Post subject: Reply with quote

Sorry to interupt the mutual agreement society, Wink but there is another point to the OP.

What research did KEF do to measure the effect of grill on or grill off ?

Its not whether I can hear it, [although it is of course..] but my question is more aligned to curiosity on where in the acoustic value chain did KEF at the time, place the effects of grill's ?

Nothing:- "it's not worth thinking about" ?
something:- "ah yes... we measured.. no effect"
No idea:- "we never tested"
something +:- - "You need grills.. and here's why"
etc

That's my real question.


Last edited by clubsport911 on Mon Oct 22, 2012 1:15 pm; edited 1 time in total
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speakerguru
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PostPosted: Fri Oct 19, 2012 1:37 pm    Post subject: Reply with quote

clubsport911 wrote:

What research did KEF do to measure the effect of grill on or grill off ?

It should be obvious by looking at the KEF grille designs over the years, that everything possible was done to minimise the measureable effect of the grilles (yes, everything was measured with and without grilles). e.g. the foam rectangle round the 101 tweeter, the bevelled edges to most grille frames, the sculptured foam of Model 104, 103 and LS5/1AC, etc., etc. The Model 1, 2, 3 and 4 grilles were masterpieces of lattice framework.

Personally, whenever I've tried it, I could never hear any difference with and without grille.
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proffski
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PostPosted: Fri Oct 19, 2012 5:17 pm    Post subject: Reply with quote

I just liked the look of most of my loudspeakers with grilles off.
Whenever I had visitors they went back on, unless of course somebody requested a peek at what lay undeneath.

I had one classic comment on the 15" Tannoy Arden's.
After removing the top grille (The other two hid the ports and contour controls)

The visitor exclaimed "Oh, they only have one driver then?" I could not be bothered to explain and put on Dave Bruebeck's 'Take Five' the Tannoys just loved playing that track!

Link: http://tinyurl.com/9h7lvu2
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clubsport911
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PostPosted: Mon Oct 22, 2012 1:16 pm    Post subject: Reply with quote

Quote:
yes, everything was measured with and without grilles


What were the measured effects ? - rough idea (this is not a memory test !)

Quote:
It should be obvious by looking at the KEF grille


And as you are so often at pain to point out... much in KEF was driven by marketing, so "looks" as a guide might not in fact be a sure sign of technical advantage !

@ proffski - great ! I do like Tannoy's:- my brother in law had / has DC Tannoy Devons (12" cone) and they were / are smmmmoootthhhhh... but not at all exciting to listen to. (Hafler amp)


Last edited by clubsport911 on Mon Oct 22, 2012 9:49 pm; edited 2 times in total
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proffski
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PostPosted: Mon Oct 22, 2012 1:22 pm    Post subject: Reply with quote

Wilson Audio, how do they measure this?

" maximum insertion loss of only 0.26 dB.
To improve on the foam grilles, the challenge was to develop and manufacture a replacement material that was both cosmetically conducive to such an Olympian product while maintaining sonic purity. Our current clothe grille material meets both objectives beautifully, exhibiting an insertion loss of only 0.06 dB!"

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speakerguru
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PostPosted: Tue Oct 23, 2012 9:07 am    Post subject: Reply with quote

clubsport911 wrote:

What were the measured effects ? - rough idea (this is not a memory test !)


The difference between grille on and off, typically ended up as +/- 1-2 dB ripples.
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clubsport911
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PostPosted: Tue Oct 23, 2012 11:37 am    Post subject: Reply with quote

Thanks. This is what was expected but of course, unproven with any science. I always assumed that grills affect HF much more than MF (and no effect on LF).

I listen grill off right now for no other reason except the covering needs some attention (it's a little stained in some areas).
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SimplySound
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PostPosted: Wed Mar 13, 2013 6:35 am    Post subject: Reply with quote

Let's take this a step further... what is the science behind porting the LF of the R107 cabinet directly in front of the MF/HF Heads? Was there something about "mixing" the Bass Wave with the MF/HF Wave from the Heads?

I always wondered about this and it is the reason I run with screens and grill. I just assumed with all of the Engineering that went into the 107 that they had tuned the diffusion of the frequency mix to work with those components.
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Last edited by SimplySound on Thu Mar 21, 2013 5:37 am; edited 1 time in total
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TL 200
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PostPosted: Wed Mar 13, 2013 10:15 am    Post subject: Reply with quote

" what is the science behind porting the LF of the R017 cabinet directly in front of the MF/HF Heads?"
I guess it was done to blow the dust from the heads. Shocked
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