audio-talk

Ant wrote: ↑Sat Aug 17, 2019 3:37 pm Open the hole up abit on the cats eye for the smallest wizzers by a couple of mil

I could do that, but whether my 61 year-old ears, would hear any improvement is debatable. I’ll give it a go tomorrow.

Cressy Snr wrote: ↑Sat Aug 17, 2019 3:15 pm Also the string recording played by Ray was badly affected by them, I’ll wager.

Indeed Steve. The Pachelbel I played at Owston was a bit disappointing, being quite 'edgy'. I was talking with someone aferwards who commented that it wasn't a very good recording but the reason I wanted to play it was because experience at home is that its an excellent 'prick up your ears' recording.

That aside, I thought your system did a lot of things very well - I enjoyed your three tracks - and they clearly work for you at home, which is ultimately all that matters. It's good to see you still squeezing more out of them too.

Ray

Ray P wrote: ↑Sat Aug 17, 2019 10:14 pm
Indeed Steve. The Pachelbel I played at Owston was a bit disappointing, being quite 'edgy'. I was talking with someone aferwards who commented that it wasn't a very good recording but the reason I wanted to play it was because experience at home is that its an excellent 'prick up your ears' recording.

That aside, I thought your system did a lot of things very well - I enjoyed your three tracks - and they clearly work for you at home, which is ultimately all that matters. It's good to see you still squeezing more out of them too.

Ray

The first indication something was amiss at Owston, was watching Greg, slowly but surely, losing the will to live, as my demonstration progressed. He was right on-axis unfortunately, and I would not have liked to have been sitting where he was. Furthermore, dismissing this as down to music choice, would have not only been arrogant on my part, but also the coward’s way out; so no, something was definitely up.

Then came your recording and Gaz’s Quincy Jones; and that confirmed the fact that the speakers were not yet, shall we say, quite...er....“optimised.” I was on-axis in those instances and the first phrase that came into my head was, “oh dear”
And unfortunately, you can’t un hear a fault, once it has imprinted itself on your perception, whatever component is to blame.

Saying to myself ”well it works at home” would have been a bit of a lazy attitude to take, hence the 2 month quest to sort the speakers out. They now sound like a turbocharged, bigger-boned version of my old 5ft Metronomes, which does seem rather ironic.

If all the above sounds like I’m saying the speakers sounded crap before I wrestled them into submission with my heroic efforts; they didn’t. There were just a couple of peaks and a bit of a rising trend that could occasionally make themselves known. Now. that the faults have been rectified the speakers sound more of a piece on a wider range of recordings.

Ray P wrote: ↑Sat Aug 17, 2019 10:14 pm
Indeed Steve. The Pachelbel I played at Owston was a bit disappointing, being quite 'edgy'. I was talking with someone aferwards who commented that it wasn't a very good recording but the reason I wanted to play it was because experience at home is that its an excellent 'prick up your ears' recording.

Ray

mea culpa..that someone was me...I am very familiar with the piece in question, having a few versions myself....and having heard the speakers many times before I was loathe to place the blame with them....

just goes to show...

Re the speakers in general....it's very easy for the listening public to pick up on what some 'experts' have criticised and carry it in their minds thereafter....I for one do not agree with the 'experts' in this respect but I do accept that Ray beleives his recording to be agood one....

for me that only leaves special circumstances to be at play in this instance. That, or my ears were getting tired by the time that track was played. I am certain I will never know which.

I thought it was you Ed but didn't want to incriminate you

Cressy Snr wrote: ↑Sun Aug 18, 2019 12:02 pm If all the above sounds like I’m saying the speakers sounded crap before I wrestled them into submission with my heroic efforts; they didn’t.

Absolutely Steve, as I said before, I enjoyed your slot and your system did some good things.

The nature of the Owston event means that everyone who demo'ed experienced some level of compromise to the performance of their kit but overall the results were pretty acceptable and there was only one pair of speakers in the afternoon that I found fell outside my envelope of acceptability.

[quote="Ray P" post_id=167926 time=1566159636 user_id=124... and there was only one pair of speakers in the afternoon that I found fell outside my envelope of acceptability.
[/quote]

Ooohh controversial

Steve, I like your approach here. Keeps the signal chain nice and simple, which is something I've struggled with when going with active EQ/crossovers etc.

IIRC, there was something that went round diyAudio for speakers with whizzers that was meant to smooth things out quite well. It was before measurement equipment became easily available, so it's mostly subjective listening impressions.

Anyway, the trick was to put a bit of foam between the whizzer and the main cone. The idea behind it was that the main cone is "terminated" at both edges (at the voice coil and at the surround), meaning it's fairly well-behaved, while the whizzer is only attached at one end - to some extent, it's free to play it's own tune.
Adding a soft mechanical coupling to the edge of the whizzer cone means the resonances of the whizzer (think bell modes etc which will have a decay time) are killed off somewhat, but it can still radiate high-frequencies.

It might be worth a bit of playing around to see if there's anything useful there. There would be a few combinations you could try, and I'd be interested to hear how you get on.
If it was mine, there's a foam I'd use - search online for "magic cleaning foam" and you'll get it - it's high-density but soft and easy to cut. Seems perfect for a job like this.

Chris

Yes, it's the famous old $0.99 tweak. Just a small ring of teased bonded acetate fibre or an equivalent thereof (nothing fancy) lightly wrapped around the base of the sub-cone / whizzer. It was done partly to attenuate excess output from the sub-cone but also the reflected transverse standing wave and output from the main cone that is blanked by the whizzer in front of it. It can work quite well.

A couple of slightly more involved alternatives which aren't reversible (unlike the $0.99 tweak):

-Self-adhesive felt dots, added strategically to the whizzer can damp this down.
-Mamboni triangles can also have a similar effect. Cut a small series of triangles out of very thin felt & attach around the circumference / periphery of the cone, sub-cone or whatever, points inward to the centre.

... then hope the outer part of the main cone is not peaking in the 2-8kHz region .... !

Or anywhere else for that matter. With a large cone it's less likely that you'll get excess resonance at higher frequencies near the circumference -the inherent mass provides a degree of self-damping. That's one reason large wideband drivers are often (some exceptions) highly directional in the HF -it's the central portion that produces much of the HF output, and the cone profile itself can then act like a waveguide, limiting dispersion. Sub-cones / whizzer cones can help with that, albeit bringing with them their own issues. As far as driver design goes, name your poison.

Be that as it may, quickest way of identifiying problematic cone modes if you don't have suitable measurement gear to hand is to gently tap the cone, from the centre out to the periphery. Listen for any significant / abrupt changes at certain points. If it's a homongenous design without decoupling rings / groves, changes in thickness or factory-applied additions, then it's potentially a larger and probably unwanted mode. Various ways of addressing that, usually best done via strategic damping / small masses, be it a ring of varnish or thin felt, a ring of felt dots or paint blocks / whatever.

Heard these earlier, I dont think they need any more tweaking
The tonal balance has smoothed and has tilted down at the top, this has had a knock on effect of bringing the midrange out abit and balancing the bass and the top up
Now that the response isn't rising in the same manner as it was
Better balanced overall

Good innit!

https://www.diyaudio.com/forums/multi-w ... genumber=1

Here Bud Purvine talks about a simple treatment of the cone to dramatically improve the sound quality. It represents a zero liability approach.