Ha! Many thanks for the extra information / link! Those look great (pine fan) -I bet you needed a new blade in that plane afterward too given how rigid they'd got...
Another upgrade:
I have to say a big big big thank you to my friend Marco, who’s great skills in wood working are permitting this pair of Silbury to be built.
With my total newbieness (is it a neologisms?) I would have committed too many errors and probably they would be now the Pisa Tower limited version of the Silbury.
I have to say a big big big thank you to my friend Marco, who’s great skills in wood working are permitting this pair of Silbury to be built.
With my total newbieness (is it a neologisms?) I would have committed too many errors and probably they would be now the Pisa Tower limited version of the Silbury.
You're welcome!
Complete new set (4) since by then Sears Craftsman tool quality had degraded to the point where they were basically 'throwaway' junk and quality replacements were commercial grade brand names I never heard of with Mercedes custom Limo level pricing relative to my crippling Federal tax, long term medical care costs net income, so have yet to replace and all things considered, seriously doubt I'll have the need. 🙁
You're welcome!
Essentially the same to the first approximation, i.e. reducing to inaudibility its theoretically infinite number of summed eigenmodes reflecting back to the driver, though best to make the rear bevel as random as practical (I use(d) a big, coarse rounded wood rasp originally and later a 'drum' bit for a large rotary grinder to 'hog' it out), otherwise more damping is required to quell all the random, yet summing, reflections otherwise modulating the diaphragm.
@planet10 thanks. May I ask how this procedure/technology came out?
It remembers me of some episodes that happened to people I know that dreamed some new ideas or solutions they felt they'd never be able to in a pure conscious way.
I'm very curious to try it, the geometry is very intriguing, even if I'm scared to damage a speaker.
It remembers me of some episodes that happened to people I know that dreamed some new ideas or solutions they felt they'd never be able to in a pure conscious way.
I'm very curious to try it, the geometry is very intriguing, even if I'm scared to damage a speaker.
EnABL is about taming the eigenmodes in the driver's TL modes BW, i.e. the traveling waves that emanate/radiate outward at the VC and/or dustcap juncture at whatever the SoS is in/on the diaphragm's construction.
In theory a point source driver is pistonic from Fs to its VC and/or dustcap juncture's frequency, so using an extreme example of a wide BW subwoofer: 19.5 Hz Fs, 7.55 cm dia. VC = ~34400/pi/7.55 = ~1450 Hz where we see a notch in the impedance, upper mass corner/Fhm = 2x 19.5/0.28 Qts = ~139 Hz, but due to its shape/construction its TL modes 'ring' all the way back to its Fhm! where T/S theory peters out to get such a wide BW and no doubt would be quite the challenge quelling them short of bonding a secondary diaphragm to it using a lossy, non hardening adhesive, which of course would also roll back its HF response to ~ its Fhm; i.e. not many 'free lunches' in audio design.
In theory a point source driver is pistonic from Fs to its VC and/or dustcap juncture's frequency, so using an extreme example of a wide BW subwoofer: 19.5 Hz Fs, 7.55 cm dia. VC = ~34400/pi/7.55 = ~1450 Hz where we see a notch in the impedance, upper mass corner/Fhm = 2x 19.5/0.28 Qts = ~139 Hz, but due to its shape/construction its TL modes 'ring' all the way back to its Fhm! where T/S theory peters out to get such a wide BW and no doubt would be quite the challenge quelling them short of bonding a secondary diaphragm to it using a lossy, non hardening adhesive, which of course would also roll back its HF response to ~ its Fhm; i.e. not many 'free lunches' in audio design.
Bud Purvine worked on the technique for some decades before he gave it to us all. A set of FE127e we sent to him, cam back, and changed my life (a bit anyway).
There is a lot of traffix on it here.
If interested in trying it:
Posts 13, 14, 15, 16 https://www.diyaudio.com/community/...ressions-techniques.119676/page-2#post1460270
Post 101 outlines the tap test
dave
There is a lot of traffix on it here.
If interested in trying it:
Posts 13, 14, 15, 16 https://www.diyaudio.com/community/...ressions-techniques.119676/page-2#post1460270
Post 101 outlines the tap test
dave
Than GM, i have not seen that discourse before. Makes a lot of sense and fits with what i have been theorizing.
dave
dave
Those 4 posts are essentially the summary (of how to go it).
Practise on something you are happy to trash if you need more practise (i did).
dave
Practise on something you are happy to trash if you need more practise (i did).
dave
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You're welcome!
It's because I've never posted it before for what I hope in retrospect is obvious 😉, just my lazy man's way to do it for the typical 'el cheapo' drivers I used since my hobby time/patience has always been in short supply, i.e. an airbrush loaded with various coatings and misted the DC and surrounding area out till the then young females found them less 'sharp'/irritating/whatever whereas to me they just sounded duller with no way to know where the point of diminishing returns was with any degree of success beyond noticing they tended to be less sibilant (a plus for me); but these forums + the world's most successful consumer audio manufacturer have over time proven to me that statistically virtually all consumers want their speakers to have some obvious sibilance.
Big drivers I did myself using an automotive pro touch up gun as these breakups could be easily seen (at least in my youth) when driven below their Fs and regardless of driver size, easily hear its HF with a mechanic's stethoscope.
Ouch. Sorry to hear that, but not surprised, the quality of most of our supposed decent 'affordable' tools & tool-bits over here has fallen off a cliff in recent years; you practically need a new mortgage to for something that's likely to last, so I'm up that similar creek, albeit luckily not being pasted by the medical care costs.
Most probably best buy can be old semi-used items from hobbysts. At least this is the impression I’ve had looking at low-to-medium price modern stuff.
Yes, in posts 13, 14, 15, 16 here https://www.diyaudio.com/community/...ressions-techniques.119676/page-2#post1460270
This is what I get:
This is what I get: