see, they added it to the surround because the driver needed it, so no cost spared, and that is my point
Troel's edge treatment of the Satori MR16 was more desirable, smoothing most of the 3 - 4 dB swing (with dip) at 1200 Hz. Where as, the SB Acoustics edge treatment reduced a peak at 4 kHz by about 3 dB also. Though a resonance peak at 4kHz can be irritating, peaks being more noticeable than dips.
Last edited:
yes, and that is what i have tried to say all the long, they did not exclude surround coating for cost reasons, they did it because the did not wanted it there
but as some said in a post above, sba are using surround coating for their midrange driver. see, sb uses the coating where it is needed not only where there is a budget
see, they added it to the surround because the driver needed it, so no cost spared, and that is my point
Which is incorrect because
a/ It's not on the surround / cone interface. It's added to the rear of the cone only, which is a different (and much cheaper) set of conditions, and
b/ It doesn't address the cone edge-resonance under discussion (as you can see in the measurements), which they would have had to expend much more time, effort and money to do. If you honestly think SB's Satori range are cost-no-object drivers with zero engineering compromises, then you are, bluntly, wrong. I can't think of any other way to put it.
Last edited:
maybe, but they did it
sba seems not to be bother by uneven freq responses, even their polycones has some nasty response peaks for being polycones, low losses seems to be their "thing"
i have not said nor have i thought that satori are cost-no-object drivers, just listen to them and it is obvious they are not, mine are pretty much useless! but what i trying to say for the tenth time is that i think they choose not to coat the surround because that will make some other parameters of the performance worse and not just the cost. if cost would have been an issue then i hope they hade excluded that decorative and very silly rubber ring on the magnet structure
yes, peaks in the response curve viewed in a waterfall plot always show some sort of decay or ringing, dips not so, so dips are better then peaks
Doesn’t matter what surround there will be some reflection. Diffractin is an added issue — something in learned from Joghn Greenbank (Tangent), another star from the UK.
dave
Hi,
Does it change the Qm of the surround ?
Does it work with rubber surrounds as well ?
These tacky glues are still heavy and thick if you take the glues for surrounds . Are they no change the weight of the cone too much - Qts- ?
I'm lost when I read some coat the outside cone, some the inner, some the inner surround.
Is it always usefull ? I have some old paper woofers in sealed, aperiodic loads, should I shellac, paint, glue the inner cone surfaces ? ... knowing the ears are not sensible too mch in the bass and upper bass dpt ?
Does it change the Qm of the surround ?
Does it work with rubber surrounds as well ?
These tacky glues are still heavy and thick if you take the glues for surrounds . Are they no change the weight of the cone too much - Qts- ?
I'm lost when I read some coat the outside cone, some the inner, some the inner surround.
Is it always usefull ? I have some old paper woofers in sealed, aperiodic loads, should I shellac, paint, glue the inner cone surfaces ? ... knowing the ears are not sensible too mch in the bass and upper bass dpt ?
I have treated many, many drivers, using more “doping” than you would use on a surround, surround, measuring them before and after, and unless you really work at it (like 10 coats on a 12” woofer) any T/S parameter changes are less than the factory variation in parameters and the differences that one gets with changes in the weather (mostly air pressure & temperature).
dave
dave
I have treated paper cones since the late ‘70s. Almost universally an improvement — most notably an increase in DDR due to the coating tieing the fibres that make up paper from moving and producing what i call cone “self-noise”. One can ruin a driver by being over generous with the coating or using anything that stiffens the cone — i have improved some cones with careful application of stuff that stiffens a cone (damar, lovely smell that), but it need sto be carefully applied and used in a specific very driver specific pattern.
Like this (from before i learned about EnABL so clearer to see). the pattern is damar, then a thinned coat of ModPodge. (aside: also shows how careful joinery with bamboo plywood makes it look like one did a whack more work than in reality — the pattern around the edge that looks like marquetry).
The tacky glue i use (Zig), does not add very much mass.
We are moving into cone treatments here. Zig on the back at teh surround interface may have alos improved ths driver (as did EnABL) but thes ewere long NLA before i discovered that trick.
dave
That's an interesting and moot point, I had considered that the protruding outwards roll surround may be beneficial in terminating energy.
However my BBC/Rogers mid/woofers have an inverted roll surround.
Also it is generally true that a much greater termination of energy is required with harder cones, especially pistonic, which tend to use rubber.
Self damping cones often have foam because they need less terminating damping.
Thank you Dave for the inputs.
What would you consider for coating the rear of a 8" bass paper cone in a sealed load please ? I assume it's about to make it both more pistonic and more linear (damping some peaks)... though I usually have low XOs with woofers : around 200/30 hz.
Edit : you firered before this post ... Thanks.
What would you consider for coating the rear of a 8" bass paper cone in a sealed load please ? I assume it's about to make it both more pistonic and more linear (damping some peaks)... though I usually have low XOs with woofers : around 200/30 hz.
Edit : you firered before this post
... Thanks.
Last edited:
But at the high range end of a mid/woofer, the cone effectively becomes the suspension for the more central part of the driver - the VC and a little more of the cone. Surely then, the energy to which you refer does not extend to the outer part, the surround, because that is a large and damped mass unable to respond to those frequencies..
Front is more important IMO, but with a woofer, and if you are careful, both sides would give you a quasi sandwich which probably be a good thing. And if you add too much with a sealed box, it will just go a little lower but reduce the sensitiveity (maybe) enuff to be a worry if you are using a passive XO.
dave
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.