audio-talk

Did a bit more work on the ‘eyes’ in the speaker grilles yesterday. I further closed down the ‘pupils’ by stitching a piece of 25 holes-per-square-inch, ‘binca’ cotton cross-stitch fabric to the back of the grille, along with the other two, previously existing mechanical filters.

Through the grille can be seen two of the elliptical apertures. The centre is clear, through to the cone dustcap at the centre of the treble whizzer.

The second eye, surrounding the centre hole, attenuates the outer edges of the treble whizzer itself, and there is a third, larger eye, invisible, behind the second one, that attenuates the radiation from the edge of the larger midrange whizzer.

The overall effect is (as we travel outwards from the driver centre) a progressive attenuation of the lower treble to upper midrange region, as all the ‘eyed’ panels are the same 4 inch outer diameter, so that the effective thickness of the material decreases, as we approach the centre of the driver. The highest treble tones pass unimpeded through the grille centre aperture.

After playing a few torture tracks, I can reliably say that, all traces of screech have been banished from the presentation and the rising response trend of this driver is effectively tamed.

The result is a rather nice improvement over the previous grilles, with clearer highs, a more detailed, midband, and the bass has come out from behind the rest of the frequency range.

Steve if you could measure this(with some precision) and get repeatable results then you might possibly have the basis of a patent....just think about it......'the Cresswell eye" or somesuch

Nice ! Good work, Steve.

Problem with all this stuff is that I’m not a scientist. I’m fine with the creative stuff and the lateral thinking that resulted in the ‘eye’ grilles but try and quantify the process and get involved with the maths and I tend to give up because of inability in that department.

Anyway, having said all that; here is a third octave RTA of the speaker in-room, taken at 1m, level with the driver centre and about 10deg off axis. Very high treble is down above 13KHz (assuming the OTL isn’t to blame) so wouldn’t be good enough for the bat-eared contingent, but the mids to lower treble content looks and sounds nice and even. There is a bit of a shelf lowering of the bass end, but the upside to this is that the bottom end is completely free from boom. The upper bass dip starting at 125Hz and continuing to 250Hz is probably responsible for the lack of subjective boom frequencies. Nothing nasty in room is being excited.

I think the performance of the speaker system with response correcting grille allows the big wideband driver to show off its best bits, and its very wide range. Purists would want a supertweeter to prop up the last half octave of treble, but as my ears drop off a cliff at 10KHz I couldn’t care less.

ed wrote: ↑Sun Nov 03, 2019 2:18 pm Steve if you could measure this(with some precision) and get repeatable results then you might possibly have the basis of a patent....just think about it......'the Cresswell eye" or somesuch

IslandPink wrote: ↑Sun Nov 03, 2019 2:40 pm Nice ! Good work, Steve.

Oh, and thanks chaps
Sure there must be prior art somewhere to do with all this grille manipulation. Using it to play around with the FR of a full range driver? It’s too obvious isn’t it?

Probably ... but it may have been in the 1930's !
Just started reading Bjorn's book and the history section, lots of peripheral stuff about the development of undersea transmission lines, how valves were created , phonograph horns etc, just amazing how diverse the ideas were and how many clever people there were experimenting with all this stuff.

Steve, does Ants 15" version of the driver "suffer" the same issues that you had with the 12" verson ?

Cressy Snr wrote: ↑Sun Nov 03, 2019 5:07 pmI think the performance of the speaker system with response correcting grille allows the big wideband driver to show off its best bits, and its very wide range. Purists would want a supertweeter to prop up the last half octave of treble, but as my ears drop off a cliff at 10KHz I couldn’t care less.

Not doubting you know your own ears but I've read we can get pleasure from high frequencies through our eyes which may explain the preoccupation with super tweeters. This audio game is not only just about ears but a whole body experience.

pre65 wrote: ↑Fri Nov 08, 2019 6:44 am Steve, does Ants 15" version of the driver "suffer" the same issues that you had with the 12" verson ?

Yes, but not to the same degree. IMO it’d still need correcting.

izzy wizzy wrote: ↑Fri Nov 08, 2019 7:52 am
Not doubting you know your own ears but I've read we can get pleasure from high frequencies through our eyes which may explain the preoccupation with super tweeters. This audio game is not only just about ears but a whole body experience.

I’ve read that too, so if you wear glasses, you must be missing out big time. Also listening with eyes closed ought to be a no-no. Most commercial high end speakers have raised treble, which makes me wonder if they know that only old gits buy hi-fi.

For me, I like the Fanes as I’ve got them now. Smoooth.

Cressy Snr wrote: ↑Fri Nov 08, 2019 9:20 am I’ve read that too, so if you wear glasses, you must be missing out big time. Also listening with eyes closed ought to be a no-no. Most commercial high end speakers have raised treble, which makes me wonder if they know that only old gits buy hi-fi.

For me, I like the Fanes as I’ve got them now. Smoooth.

IME raised treble enhances "imaging" but don't sound right to me i.e. not natural whatever that is. The "fad" for unloaded MCs does something similar as they have rising top end when unloaded.

I reckon that HF gets round the edges of yer glasses and through yer eyelids

I had my Tannoys too hot at Owsters due to new crossover caps. Knocking them back a bit gives you a bit more ,aaaahhh and relax. Smooth is the way forward

Been sprucing up the sound of the Fanes today,

Re-cabled them inside and added back the internal lagging I’d taken out about 18 months ago. An additional innovation I’ve been mentally toying with for a few months was also put to work today.

I’ve turned the horizontal holey brace just below the driver, into an acoustically resistive coupler to the chamber that lies below said brace. I did this by laying coarse, fibrous wool over the brace and gluing it down with spray mount. Naim did their own version of this technique with their SBL speaker in the mid to late ‘80s, although they used a series of interlocking ‘fingers’ of some material or other as the resistive element and their lower chamber was a separate box. And though the SBL were ear-splitting in the mid and lower treble region, there’s no denying that the bass from those speakers was shockingly good.

The results have been well worth a morning spent with wire, wadding, felt and soldering iron and a re-opened mind. A haze of coloration has been removed and the bass has tightened and extended itself beautifully; everything sounding fresh and clean as it were.

Hi Steve
I have heard and have developed a soft spot for these Speakers through my visiting Owston,
I now have memories of them being their two times, and on each visit these speakers transported me to another place.
I know from your posts and pre presentation descriptions you have made slight changes to them each time I have auditioned them.
For the Record, I like them a lot, they transport me into a place of Solace and relaxation.
They are still on my 'must be done' list.
There is a Mr Nixie - STC 11 Amp, that I would very much like to look into, to be used to Direct Drive them,
'No Speaker Cables' is the intention.
The ongoing investigations being undertaken by yourself and the reporting back of the positive findings are always welcome at this end.

izzy wizzy wrote: ↑Fri Nov 08, 2019 7:52 am

Cressy Snr wrote: ↑Sun Nov 03, 2019 5:07 pmI think the performance of the speaker system with response correcting grille allows the big wideband driver to show off its best bits, and its very wide range. Purists would want a supertweeter to prop up the last half octave of treble, but as my ears drop off a cliff at 10KHz I couldn’t care less.

Not doubting you know your own ears but I've read we can get pleasure from high frequencies through our eyes which may explain the preoccupation with super tweeters. This audio game is not only just about ears but a whole body experience.

Don’t forget the teeth

Cressy Snr wrote: ↑Fri Nov 08, 2019 9:20 am

izzy wizzy wrote: ↑Fri Nov 08, 2019 7:52 am
Not doubting you know your own ears but I've read we can get pleasure from high frequencies through our eyes which may explain the preoccupation with super tweeters. This audio game is not only just about ears but a whole body experience.

I’ve read that too, so if you wear glasses, you must be missing out big time. Also listening with eyes closed ought to be a no-no. Most commercial high end speakers have raised treble, which makes me wonder if they know that only old gits buy hi-fi.

For me, I like the Fanes as I’ve got them now. Smoooth.

Doesn’t work that way for me, yes my hearing tails off, but it’s what I hear real life, I want a system to sound real life. So I wouldn’t want extra treble it wouldn’t be my real.