What is Peerless Nomex cone like?

[nodiak]

Is it's stiffness like a hard paper or more like typical softer paper cones, or other? Woven, pulp,?
Any comparison appreciated. I am considering the 5-8" non phase plugged models.
Thanks, Don

[JonMarsh]

Hard paper. It's a hybrid of paper and nomex.

Why the non phase plug models? They don't have Faraday rings, and have higher midrange distortion.

[nodiak]

Thanks Jon. Non pp for budget and simpler xo, don't have diy xo skills. Possibly use the 832973's for a smaller sealed Zaph style tmm as i now have a sub and don't want/need bass below 80-90 f3. But I need more efficiency than a single midwoofer as I use a 20 watt/ch tube amp for mains.
I thought they had rings, just less copper?
Don

[JonMarsh]

Probably much less- compare the impedance curves. Impedance rise = inductivity modulation in midrange. Eliminating that is a part of the "secret sauce" that makes drivers like the SS midwoofers, Seas Excel, and Dayton RS series fairly special. Oh, the 830883 is a very nice driver, too, IMO. One of the best balanced in performance and usability (easier to design with than Seas Excel or Dayton RS, great midrange performance...

Standard Nomex series looks a lot like the old 850439





Compare with 830883






If you want easy to design with and decent all around performance, try the Vifa XG18.

[nodiak]

OK, I see it better with the graphs.
The XG18 looks good and I'll definitely consider it. I do still have early gen. SS poly 7" 8543. Softish mids, but wonderful "depth/ambience/power handling". Always wish I'd gotten the paper 8542's instead, now they're all out of my price range.
I should have time to finish NP's finally this next week, cabs are done , xo's to go (yes, I'm properly embarassed about the long delay ).
With the new sub I am thinking about sealed for them too.
Don

[augerpro]

I don't know guys. I think the Peerless Nomex is getting a bad rap. I think if we keep things in economic perspective it looks much better. It's easy to say go for the Exclusive because it's just a "little" more. But the price difference is almost the same between the Nomex and Dayton RS150. So if you're looking at the RS I say go for the Nomex. And that can go on for ever. if you're looking at EXclusive, the Usher is just a bit more. If your looking at Usher than Excel is just a bit more. Next thing you knwo someone who started with a Dayton woofer is looking at buying an Accuton. I'm sure your all familiar with this process, I know I am

The HD looks overall better I think than the RS150. F3 and F5 have a bit of a peak, but it's a bit lower than the RS and much smoother throughout the band. The RS is just crazy everywhere, even if no one peak is really through the roof. Well maybe F3 at 3300 Hz. And smoother FR makes it easier to work with for us beginners.

And pictures don't do the Nomex justice. I've just bought a Nomex and RS150 for some side by side testing and listening. All the pictures of the Nomex make it look grayish. It's actually pitch black. Where the Dayton looks cool, the Nomex looks classy. Anyhoo , that's my newb .02, I'll run and hide now :B

[JonMarsh]

Yeah, better is the enemy of good, and best the enemy of all, but it's never black.. and white, but shades of gray...

Ya gotta pick your choices and then learn to live with them.

[cotdt]

actually the old peerless exclusives (2006) were grey, but now they are black (starting late 2006).

[capslock]

The standard Nomex has an aluminum shorting ring below the top plate, the exclusive has an extra copper sleeve in the gap and an aluminum plug that acts like a top shorting ring.

The lower ring reduces low frequency flux modulation distortion (2nd harmonic) but does little about the magnitude and position variation of the inductance.

The exclusive also has an extended VC former that the dust "cap" is glued to. This makes for a stiffer overall cone, but this triangle-like cross section (inner part of cone, dust cap, former) seems to have modes of its own.

[mazurek]

The 1khz dip of the peerless exclusive makes the crossover different, more complicated. The exclusive also has a larger on axis high frequency rise than the standard nomex, which I don't think is addressable in the crossover because they have the same flat off axis response. I naively tried the exclusive as a drop in replacement for the nomex, and the 1khz dip changes the sound significantly.

Having a sub open up your options a bit.

[Amphiprion]

cotdt,

Do you mean black frame color, or have they made the grayish nomex look black? I SO hope it's the black frame color...

[capslock]

The 1khz dip of the peerless exclusive makes the crossover different, more complicated. The exclusive also has a larger on axis high frequency rise than the standard nomex, which I don't think is addressable in the crossover because they have the same flat off axis response. I naively tried the exclusive as a drop in replacement for the nomex, and the 1khz dip changes the sound significantly.

Having a sub open up your options a bit.

Which exclusive are you talking about that has a 1 kHz dip?

The on axis frequency rise in all the exclusives seems to be due to lower inductance, so on AND off axis should be affected in the same way compared to the standard Nomex. You can counter this by adding an external series inductor of about 1 mH, maybe with an RL circuit in parallel.

[fjhuerta]

Those Peerless drivers really look interesting. I've been aching to try something (anything) without metal cones - I love their sound, but crossover design can get pretty expensive and complex.

One thing that I don't really like about the Peerless is the price - I can get a lot more by going the Dayton RS way, or so it seems.

Would the extra $$ paid for the Peerless pay off during crossover design? If so, is it possible to create as speaker as accurate as a hard metal conee one with Nomex / Poly?

[cotdt]

The smaller Exclusives (like the 5.5" and 4") don't have that ~1kHz dip, but the 7" and 8" versions do. I think it's due to a less stiff cone of the larger models mating to the surrounds, thereby creating a surround impedance mismatch. in the worse case scenario it's a cavity resonance but if so, wouldn't there also be a lot of distortion in the range of the dip? Anyway, I don't think it's so serious because they sound good subjectively.

what's odd is that it the 5.5" version is more sensitive than the 7". and zaph tested them at a higher output in his distortion tests, and yet it still had lower distortion than the 7". no midrange dip either, and subjectively snappier bass and even better sound. xmax is actually the same for all the exclusives via the kippel test, which is 6mm one-way. the 3.5mm figure is underrated.

The 5.5" is of the 831 series while the 7" is of the 830 series. The 831 series has a black cone with a different texture to it, and a centered phase plug, while the 830 series has a grey cone usually with a poorly built off-center phase plug.

[mazurek]

Which exclusive are you talking about that has a 1 kHz dip?

The on axis frequency rise in all the exclusives seems to be due to lower inductance, so on AND off axis should be affected in the same way compared to the standard Nomex. You can counter this by adding an external series inductor of about 1 mH, maybe with an RL circuit in parallel.

What codt said...

Off axis response does follow that trend, but is more pronounced for the smaller diameter one.

[augerpro]

Here are some pics of Nomex and some others undergoing breakin.

[augerpro]

Yeah, better is the enemy of good, and best the enemy of all, but it's never black.. and white, but shades of gray...

Ya gotta pick your choices and then learn to live with them.

Hehe I don't know what the he** you just said Sounds like a Greatful Dead lyric...I guess it's along the lines "if that's the sort of thing you like, then I guess you'll like that sort of thing" It's perfect for answering questions you don't want to answer.

[mbutzkies]

Have any of you noticed a difference on new vs older 7" HDS exclusives?

The older datasheets do not show a dip above 1KHz whereas the new datasheets do. Zaph's test seems to confirm the new datasheets FR.

The datasheets have different VAS leading me to believe that they changed the spider/surround without giving it a new part number. I also think the changes are more significant than just break in. The change happened around the same time peerless introduced the 831882

I bought and tested an 883 a while back, and don't remember that dip. Of course, I did not save the data and don't have the drivers.

Do any of you have older HDS exclusives that you can compare to new production, and show differences, either cosmetic or measurement based?

FYI, the madisound datasheet is the old one, Tymphany is the new datasheet.

https://www.tymphany.com/datasheet/printview.php?id=3

https://www.madisound.com/pdf/peerless/830883.pdf

[augerpro]

Have any of you noticed a difference on new vs older 7" HDS exclusives?

The older datasheets do not show a dip above 1KHz whereas the new datasheets do. Zaph's test seems to confirm the new datasheets FR.

The datasheets have different VAS leading me to believe that they changed the spider/surround without giving it a new part number. I also think the changes are more significant than just break in. The change happened around the same time peerless introduced the 831882

I bought and tested an 883 a while back, and don't remember that dip. Of course, I did not save the data and don't have the drivers.

Do any of you have older HDS exclusives that you can compare to new production, and show differences, either cosmetic or measurement based?

FYI, the madisound datasheet is the old one, Tymphany is the new datasheet.

https://www.tymphany.com/datasheet/printview.php?id=3

www.madisound.com/pdf/peerless/830883.pdf

I don't know about the exclusives. But I have the 832873 Nomex which is also the new cone. We'll see if it measures differently than the 830873 Zaph measured.

[mazurek]

Have any of you noticed a difference on new vs older 7" HDS exclusives?

The older datasheets do not show a dip above 1KHz whereas the new datasheets do. Zaph's test seems to confirm the new datasheets FR.
...

I purchased some 6/26/06, they have the dip.

[cotdt]

i've seen plots of the older Exclusive 7" and it has no dip past 1kHz, but the new ones do for some odd reason. a negative improvement?

well at least i can confirm that the 5.5" version is fine.

[augerpro]

Those Peerless drivers really look interesting. I've been aching to try something (anything) without metal cones - I love their sound, but crossover design can get pretty expensive and complex.

One thing that I don't really like about the Peerless is the price - I can get a lot more by going the Dayton RS way, or so it seems.

Would the extra $$ paid for the Peerless pay off during crossover design? If so, is it possible to create as speaker as accurate as a hard metal conee one with Nomex / Poly?

That's exactly what I intend to find out. Of course "accuracy" and "detail" are tough to measure, so it really comes down to what I think I hear for myself. I also have a some Vifa D26NC55's, XT25's, and a pair of SS9800's. I'm going to build some small bookshelf speakers with these and the Nomex and RS150. I figure if there is any truth to the hard/soft dome and metal/paper myth these would be good candidates to use.

[capslock]

Interestingly, they issued a new part number for the 5 1/4 in. Exclusive, but the parameters are exactly the same, and the graph seems to have been recycled:

http://www.tymphany.com/datasheet/printview.php?id=2

http://www.tymphany.com/datasheet/printview.php?id=323

Strange, they changed the part number for the one driver where the difference was only cosmetic (both according to data sheet and codt's measurements), but they did not change the part number for the 7 in. where there was a significant difference in frequency response.

The 8 in. had the dip even in the original version, but for the 7 in. it is new. The dip is typical of soft and semi-hard drivers, Scan Speak and Audax had this a lot. It is attributed to a cone edge reflection, where a wave travels radially outwards and gets reflected by the cone due to impedance mismatch. There are band aids, such as the cutting out segments of the cone edge as done by Vifa (flexing is still there, but with the local variation in the reflection point, the reflected wave cancels in the far field). Another fix is using a lossier surround or use some glue to goo up the inner edge of the surround.





Can't

The dip is typical of

[mbutzkies]

I always associated a 1khz dip in a 6.5" with cone edge resonance, myself. It appears they tried to improve the bass by reducing the stiffness and damping of the spider/surround. I do not know if they changed the surround, the Rms values are different but not as much as the Cms values. There is a little funkyness at 1khz on the old datasheets as well, but nothing like the dip that the new datasheets or Zaph's test show.

I am pretty sure Scan breaks in drivers before they are tested, and I believe vifa did not. I do not know if peerless breaks in drivers before measurement. can anybody shed light on this?

the two companies that really talk about cone edge are B&W and Seas, Seas uses hard cones to get rid of the dip, and B&W gets rid of the surround(mids). If it was as simple as a mechanical impedence(stiffness) mismatch between cone and surround, shouldn't a lower Rms have helped instead of hurt the 1khz FR? I am thinking the alleged weaker surround gives less support to the edge and some part of the surround/cone edge goes into cancellation with main cone leading to the dip, sorta like a whiplash effect.

Does anybody have the K&T review or any other third party FR data on the 830883 and can discribe the FR respones at 1khz? I have seen MarkK's data, It has an slight impedence bump at 1.1Khz but baffle effects seem to dominate the FR.

In addition, thanks to Mr Marsh, MarkK and Zaph for publishing their data.

[fjhuerta]

That's exactly what I intend to find out. Of course "accuracy" and "detail" are tough to measure, so it really comes down to what I think I hear for myself. I also have a some Vifa D26NC55's, XT25's, and a pair of SS9800's. I'm going to build some small bookshelf speakers with these and the Nomex and RS150. I figure if there is any truth to the hard/soft dome and metal/paper myth these would be good candidates to use.

I feel pretty stupid now. I bought the 8" Exclusives, and now I realise they have a dip I may not be able to fix by any means.

I saw the Madisound graphs and thought "this is a *Good* driver!"

No more. Next time, I'll buy drivers based on Zaph's, Jon's, Markk's and everyone else's measurements. I feel I just dropped $200 (including s/h to Mexico) down the drain... :M

[dlr]

Cone edge resonance is difficult to visualize

I am thinking the alleged weaker surround gives less support to the edge and some part of the surround/cone edge goes into cancellation with main cone leading to the dip, sorta like a whiplash effect.

I've experimented a bit with tweaks for cone/surround resonance. As capslock points out, applying something on the inner edge of the surround can work in the right situation. Parts Express sells "The Wet Look" that is a special polymer-based acrylic (if I've got the description correct) that seems to be very much like what OEMs sometimes use for this purpose.

Here's what I think may be the situation. The surround material and shape are critical. Note that some drivers (SS in particular) still have treated foam surrounds as that appears to be a better impedance match in some cases. But also note that many of the newer drivers, mostly SS, but some Vifas I've seen, (G18RNX-P, PL series) have a surround with a gradually tapered inner section rather than a symmetric roll shape. This appears to distribute the energy deeper into the surround that may allow for it to better damp the signal and be a better impedance match.

Adding material to the inner edge of a more standard surround shape (SS 13m/8640,12m/4630) may effectively do the same thing. It stiffens the surround at the roll/flat section area that helps prevent the surround from flexing only at this edge and causes the energy to flex the surround up into the roll section farther which passes more energy through flexing into more of the surround.

This isn't seen in the hard coned drivers since they aren't flexing to any significant degree prior to extreme breakup that is probably not easily controlled by the surround. I suspect that there's just too much energy in the modes of hard cones to damp.

That's my theory for the time being.

[JonMarsh]

I feel pretty stupid now. I bought the 8" Exclusives, and now I realise they have a dip I may not be able to fix by any means.

I saw the Madisound graphs and thought "this is a *Good* driver!"

No more. Next time, I'll buy drivers based on Zaph's, Jon's, Markk's and everyone else's measurements. I feel I just dropped $200 (including s/h to Mexico) down the drain... :M

I think you could do a pretty nice three way with them- something to keep in mind. Can you get the Dayton drivers also? Maybe the RS52 on the mids, or a good 4-5" midrange. Look at John Krutke's 5" driver measurements as well as John K's. I havne't looked at much in that range, until very recently. I have a set of the 5" Tang Band Titanium cone midranges coming this week. What I may be doing with a 10" three way might be adaptable to you for an 8" three way; I'm trying to keep the cost reasonble for this set- but haven't determined all the driver choices yet. Could be a couple of variatinos. (I have a set of RS270 that I've always wanted to do something cool with, but haven't figured out exactly how to go...


BTW, I'm pretty bummed with what I'm hearing about the newer 830883; I've got two pair of the "orginal", but there's not a lot of sense in doing a good desing (except for myself) if the driver has changed that much...

[fjhuerta]

I think you could do a pretty nice three way with them- something to keep in mind. Can you get the Dayton drivers also? Maybe the RS52 on the mids, or a good 4-5" midrange. Look at John Krutke's 5" driver measurements as well as John K's. I havne't looked at much in that range, until very recently. I have a set of the 5" Tang Band Titanium cone midranges coming this week. What I may be doing with a 10" three way might be adaptable to you for an 8" three way; I'm trying to keep the cost reasonble for this set- but haven't determined all the driver choices yet. Could be a couple of variatinos. (I have a set of RS270 that I've always wanted to do something cool with, but haven't figured out exactly how to go...


BTW, I'm pretty bummed with what I'm hearing about the newer 830883; I've got two pair of the "orginal", but there's not a lot of sense in doing a good desing (except for myself) if the driver has changed that much...

Hi Jon, thanks for your input, as always.

I'm thinking about a three way. I have a thread running about dipole designs, and I was thinking an MTM panel with a pair of Dayton RS125s and a Seas 27TBFC, with a ported bass module using the Peerless may do the trick. I'll surely check out Evil Twin's 3 way design. With any luck, the Force will be strong on my design, too

The thing is, I originally wanted to build a simple 2 way with an easy to build crossover. Oh, well. Next time, I'll use the Vifa XT / XG drivers.

BTW - I've used a set of 4" T-B Titanium drivers... the W4-1337s, IIRC, and loved them to pieces. They were (subjectively) very smooth and sweet in the midrange, and they were flat up to 7 or 8 Khz when I measured them. A complete joy to work with and listen to - I built an MTM with an RS28 with them, and my sister took them away from me in less than a week.

[jkrutke]

Regarding the Peerless changes, I'm keeping an eye on this thread to see what you guys come up with. Changes in a product line are a bad thing, even if the changes look like improvements. Guys posting or building designs with these woofers now have to be concerned about what version they have. Well, at least the 5.5" has a new part number, which is a step in the right direction to identify a version.

To summarize what I think I see here:

Peerless 5.5" 830882 discontinued, replaced with the 831883 version but has no sign of any differences other than a darker cone color and better centered phase plugs.

The Peerless 7" 830883 does not get a new number but some differences in performance are evident before and after mid 2006. I await anyone's confirmation of everything that's different between old and new 830883's. If there is no new part number, people are going to avoid using this driver due to the confusion.

Something that's unfortunate is that I don't have date of manufacture data for most of the drivers I test, so I only note the date of testing.

I feel pretty stupid now. I bought the 8" Exclusives, and now I realise they have a dip I may not be able to fix by any means.

If you're interested in some recent test results for the 8" HDS Exclusive, here ya go. It's really a pretty good driver actually. Same conditions as my 5.5" tests.

http://www.zaphaudio.com/temp/830884.zip

[fjhuerta]

If you're interested in some recent test results for the 8" HDS Exclusive, here ya go. It's really a pretty good driver actually. Same conditions as my 5.5" tests.

http://www.zaphaudio.com/temp/830884.zip

Thanks a lot for that link, John. That dip isn't really that obvious in your measurements, and from the HD graphs, I'd suppose it'd be a great driver with a 1.3 KHz crossover, or so.

Just one question... do you think the dip will not be noticeable in a two way design, or should I stick with a three way? I'd definitely love to mate it with the 27TBFCG at around 1.4 KHz with some steep slopes.

[jkrutke]

Thanks a lot for that link, John. That dip isn't really that obvious in your measurements, and from the HD graphs, I'd suppose it'd be a great driver with a 1.3 KHz crossover, or so.

The impedance glitch at 800 hz might make Jon freak out, :E but I could actually use this woofer as high 2kHz with the only negative being the power response issues from operating a large cone up so high. It's very well controlled up high for an 8" driver. Most of us are used to metal cone monsters melting your ears if you were to cross them that high. I've still got that pair sitting in my closet waiting to be put in a 2-way with the HDS tweeter, but I don't know if I'll ever have time. I've got 4 or 5 other projects on my plate at the moment.

[JonMarsh]

Hi Jon, thanks for your input, as always.

I'm thinking about a three way. I have a thread running about dipole designs, and I was thinking an MTM panel with a pair of Dayton RS125s and a Seas 27TBFC, with a ported bass module using the Peerless may do the trick. I'll surely check out Evil Twin's 3 way design. With any luck, the Force will be strong on my design, too

The thing is, I originally wanted to build a simple 2 way with an easy to build crossover. Oh, well. Next time, I'll use the Vifa XT / XG drivers.

BTW - I've used a set of 4" T-B Titanium drivers... the W4-1337s, IIRC, and loved them to pieces. They were (subjectively) very smooth and sweet in the midrange, and they were flat up to 7 or 8 Khz when I measured them. A complete joy to work with and listen to - I built an MTM with an RS28 with them, and my sister took them away from me in less than a week.

Thanks for the feedback- I have a pair of W4-1337 on the way, shipped on Monday, so with any luck I'll have a look at them this weekend. I'm looking for something that goes up clean a bit higher than average, so it will be interesting to see how they stack up against a 2" dome or 3" cone.

[mbutzkies]

My goal was not to scare people away from Peerless Nomex, The ones I used were great and I still would use them.

My goal is: one, to try to document the changes in production, and second, to bitch about driver manufacturers that change their products without giving it a new part number. I think that is really bad form.

For what its worth, I emailed madisound, and all they said was to use the tymphany datasheet. I would be willing to shoot an email off to peerless but I do not know any technical people there.

fjhuerta: practically all non-metal cones have that dip, I think you will like the 884 driver. If you are mating an 8" to a tweeter, I would recommend using an ellyptical crossover with a waveguide on the tweeter. these crossovers have a null about one octave above the crossover point, So I would put the crossover point at half the resonance frequency of the driver~1500-1550hz.

Also, take a look at your spider, I think HDS exclusives uses a progressive spider(not sure), that might cause you problems if you don't use a sub. A progressive spider has non-uniform hills and valleys, so it would be easy to check.

DLR: If I understand you correctly, you applied this "wet stuff" with a brush and if got rid of the dip. Does this material remain soft or crack? Have you tried other materials, latex, vinyl, etc? It sounds like a pretty neat trick, I will probably try on some cheap drivers first. Thanks for the tip.

Off topic: I wrote you a long time ago to see if you finished testing/tweaking the MDT33, I was wondering what you finally came up with?

[dlr]

Not done with the 33 yet, but almost

DLR: If I understand you correctly, you applied this "wet stuff" with a brush and if got rid of the dip. Does this material remain soft or crack? Have you tried other materials, latex, vinyl, etc? It sounds like a pretty neat trick, I will probably try on some cheap drivers first. Thanks for the tip.

Off topic: I wrote you a long time ago to see if you finished testing/tweaking the MDT33, I was wondering what you finally came up with?

The dip was not totally eliminated, but it was reduced significantly. I had wanted to try this on a cheap driver as well. The Insignia was just the ticket. I may go back to a few older drivers lying around that appear to have the same problem to see if they can be improved as well.

Sorry about the email. I think that I recall it. At times I read email and intend to respond later and then end up forgetting. I'm really due to get back to the MDT33's and some other driver stuff. I set them aside to do other work. They don't seem to be amenable to much improvement, though. I did spend some time with them. The owner even sent me some replacement domes that were no better. I've been disappointed in some of the QC issues with Morels. My first set of four replacement domes were all excellent, so I bought more some months later. There all had linearity problems. When I finish the MDT-33 tests, I'll add the measurements to my site.

What I don't like at all about the MDT33 is that the outer metal shell that encases the magnets creates a clearance problem with the connectors. That small assembly has to twist out a bit. The assembly doesn't drop cleanly into place, it has to be pressed. The former is not centered until pressed into place.

It has all the appearance of using existing driver components to create a new one without re-designing this piece to accomodate the changes.

[capslock]

The impedance glitch at 800 hz might make Jon freak out, :E but I could actually use this woofer as high 2kHz with the only negative being the power response issues from operating a large cone up so high. It's very well controlled up high for an 8" driver. Most of us are used to metal cone monsters melting your ears if you were to cross them that high. I've still got that pair sitting in my closet waiting to be put in a 2-way with the HDS tweeter, but I don't know if I'll ever have time. I've got 4 or 5 other projects on my plate at the moment.

John, was this an older gray or a newer black 8 inch? I recall Jon measured an old one about a year ago and it had a significant dip, more than the one you have.

[jkrutke]

John, was this an older gray or a newer black 8 inch? I recall Jon measured an old one about a year ago and it had a significant dip, more than the one you have.

Honestly, I don't think I've ever seen one of the "black" cones discussed in this thread. All of the ones I've had my hands on looked gray. The 8" is the only one that I know the manufacture date of - Early june 2006. It's probably similar or newer than what Madisound has in their stock right now.

[capslock]

Over on the mad board, John Kreskovski has posted graphs of two older and two newer 882s. Only one of the new 882s shows the 1.2 kHz dip.

[cotdt]

Over on the mad board, John Kreskovski has posted graphs of two older and two newer 882s. Only one of the new 882s shows the 1.2 kHz dip.

By newer do you mean the black cones with the new dimples? I measured two of mine and didn't find any 1.2 kHz dips. And I find it hard to beleive the change to the 831 series is entirely cosmetic, because the cone is about 1mm deeper and the voice coil now raises a good 3-4 mm above the cone. The frame has a different texture to it and there's also a new surround with an orange color. Also they used to use a lot of glue and now I don't see any. Surely that must change the TS parameters. Madisound just happened to send me the last old 830882 and a new 831882 when I ordered a pair. I told them I can't use a grey cone on one speaker and a black cone on another, so they sent me another 831882.

[jkrutke]

...and there's also a new surround with an orange color.

Considering the color scheme of the old HDS, an orange surround just about takes the cake. I'm sure you mean it's black with a sort of orange tint, but still, this one's too big for the fashion police to handle. We'll have to call in the fashion SWAT team. :B

[cotdt]

Considering the color scheme of the old HDS, an orange surround just about takes the cake. I'm sure you mean it's black with a sort of orange tint, but still, this one's too big for the fashion police to handle. We'll have to call in the fashion SWAT team. :B

Oops I meant orange spider, not surrounds. Otherwise... that would be a bit too much!

[capslock]

By newer do you mean the black cones with the new dimples? I measured two of mine and didn't find any 1.2 kHz dips. And I find it hard to beleive the change to the 831 series is entirely cosmetic, because the cone is about 1mm deeper and the voice coil now raises a good 3-4 mm above the cone. The frame has a different texture to it and there's also a new surround with an orange color. Also they used to use a lot of glue and now I don't see any. Surely that must change the TS parameters. Madisound just happened to send me the last old 830882 and a new 831882 when I ordered a pair. I told them I can't use a grey cone on one speaker and a black cone on another, so they sent me another 831882.

According to John Kreskovky's post over at the Mad board, the new and old 7 in drivers had the same black-grayish color.

[augerpro]

Here is the FR from my 5.25" Nomex I posted the pic of earlier. Haven't figured out the CSD and HD stuff yet so I don't know if cone behavior has changed. True resolution should be about 142 Hz.

[augerpro]

Here's my baffle. Note the scale difference also. The slight peak at 1k and dip at 1.6k are probably baffle related. All in all a pretty smooth driver I think. I spliced the nearfield at 400 Hz so the major baffle effects don't show up.

PS what is a good sound to use to measure SPL with my Radio Shack meter? I'm using this DMM http://www.partsexpress.com/pe/showd...number=390-513
Using slow and c weighting. Voltage wasn't real steady, but at roughly 2.8 volts I got 90 dB with white noise and 84 dB with a 1K tone. That 84 dB tone was earsplitting though 8O

[SpeakerGuy]

I've experimented a bit with tweaks for cone/surround resonance. As capslock points out, applying something on the inner edge of the surround can work in the right situation. Parts Express sells "The Wet Look" that is a special polymer-based acrylic (if I've got the description correct) that seems to be very much like what OEMs sometimes use for this purpose.

AFAIK most OEM coatings go on white and dry clear. I picked up a pint of "Wet Look" at the last PE tent sale. I might try some on some Peerless Nomex 830875 woofers I have. I also have some of the 830884 8" Exclusives, but I've only got one pair of those, so I'm a bit more hesitant. A couple of you were talking about 2-ways with the 830884 - I think the RS28F would be a great choice for that.

What would be really cool would be if somebody found a physical modification to do to the 830875 to smooth out the top end - the way Mark McKenzie has on various TB drivers over on DIYAudio...

[dlr]

AFAIK most OEM coatings go on white and dry clear. I picked up a pint of "Wet Look" at the last PE tent sale. I might try some on some Peerless Nomex 830875 woofers I have. I also have some of the 830884 8" Exclusives, but I've only got one pair of those, so I'm a bit more hesitant. A couple of you were talking about 2-ways with the 830884 - I think the RS28F would be a great choice for that.

What would be really cool would be if somebody found a physical modification to do to the 830875 to smooth out the top end - the way Mark McKenzie has on various TB drivers over on DIYAudio...

PE used to sell only a black version. They now sell clear. I have it, but have not yet tried it.

The usage is as far as I know almost never for the top end. It does usually have some impact there, but it's primary function on the inner ridge of the surround is for the characteristic problem around 2K that is due to mismatched termination impedance. I would not consider it for upper end only in most, if not all, cases. The impact in other areas could even be detrimental. Each driver cone shape, material and surround termination (even the glue) has an impact, so caution is in order.

Looking at the Peerless datasheet I'd say there will be little benefit and a very good chance of detrimental effects. That driver looks to be admirably smooth. The crossover should easily handle its peak. Note how quickly it diminishes off-axis.

Dave