George (on Topic Only)

This also brings up the question of: Does a zero distortion, flat frequency response, sound better than a response with peaks, dips, and slight distortion?

Take for example the tube amp discussion. They (tube amps) generate 2'nd harmonic distortion in the criticial midrange frequencies, which some people desire. Also consider that people think drivers with higher distortion sound louder than drivers with very low distortion. They might not be louder, but they sound louder. Polk once designed a speaker with a perfectly flat frequency response, and when they compared that speaker to one of their current designs (at the time), the pannel of listeners preferred the speaker without the perfectly flat response.

My personal favorite midrange is made by Seas. From recent Klipple tests in Voice Coil magazine it should by no means be king-ding-a-ling of the midrange area, but I prefer the sound of many Seas midranges to other competitive drivers. To me, there's more to consider than only numbers when designing a speaker. However, you can't ignore numbers when designing, so it's a bit of a catch twentytwo.

 

That is the exact reason why I feel there are two different kinds of SQ. One is the more traditional one where the lowest distortion numbers and flattest frequency response is desired to create the closest reproduction of reality possible. The other is what I call surreal SQ. It is what we prefer personally. It has some added distortion or frequency peaks like what you mention above. These can sound better to the individual for many reasions. One would be because those added peaks are at the same point and amplitude as the hearing loss of that individual. So they are hearing it flat in their mind, even though it doesnt sound like their precieved reality at the moment. It's taking them back to an earlier age before the hearing loss. Another reason is because maybe the peaked frequency is muffling a problem area in the system. And finally the biggest reason is because it makes the music more exciting. It's kind of like going to see a movie. They present to you their version of reality, but the movie has been greatly changed and processed from when they first filmed it. For instance, they changed the sounds of the gun shots by adding more bass. If you have ever been to a gun range, you would know what a real gun shot sounds like, which is different than what is portrayed in the movies. But this change in the sound made it more exciting. Also they have actually changed hues in the picture. This will effect the mood, crispess, and as mentioned earlier excitement of the picture. All this leads to a surreal picture of reality that moviegoers enjoy.

Now I'm definitely not saying that surreal SQ is bad. If you looked at my listening habits, you will notice that the sub is boosted. I do this because I enjoy it. But it is definitely not a perfect reproduction of reality.

From a design standpoint, it is very difficult to build your products to please everybody. So a good goal is to make it as close to real SQ as possible, and let the user adjust it to their preferences. After all, it is much easier for someone to add a peak to the music, or adjust the enclosure size for a certain Qtc to gain some distortion than it is for somone to take a higher distortion speaker and get rid of the distortion. That's why I think flat BL subwoofers (as long as they are designed correctly) will please a great deal more people if they took the time to adjust it than other subs.

 

is this supposed to be this:

Vas: proportional to Cms and the square of Sd (double Cms doubles Vas, double Sd quadruples Vas).

?

eric

 

i think the whole "what is sq, perfect reproduction or perfect sound?" thing kinda like the Chicken & the Egg..... i don't think anybody will ever figure out, and agree upon what sq really means.

with that said.... i prefer the perfect reproduction since perfect reproduction remains constant.... it'll always be the same, whereas perfect sound varries from person to person.

tho, this means perfect sq isn't perfect for everybody

 

I explained this on page two. [/b][/quote]
no, you explained how progressive role spiders work

what I'm wondering, is what other specs change, even as linearity stays constant.

remember, this whole discussion centers around the fact that even if ALL specs

are constant, they can still introduce distortion out the wahzoo........

kinda depressing, really. perhaps the better question is: How constant do the

specs stay from enclosure to enclosure? Even still, klippel, dumax, and beta

testing is all done using the same enclosure for every sub, or no enclosure at all.

What's interesting is how the t/s specs change as in-box compression increases, or

decreases (like a vacuum), and condones or restricts cone movement, other than

effecting effeciency.........





Jeff

 

I'm almost certain I like a flat response curve... I have some 3" and some 2" Tang-Band drivers in my room right now. The 3" have three times more linear excursion and a ton more displacement even at lower excursion. BUT the 2" driver is much flatter and I prefer it's sound hands down.

Anyone know how flat B&W speakers are in general? I heard some a few years ago and I have yet to hear anything I like more... They were B&W 705s, or the older model equivalent if they have updated them. They claim 46Hz – 25kHz ±3dB as the frequency response which is pretty darn flat and I absolutely loved those speakers. To this day I haven't heard anything I like better.

 

Nis,

Good catch - it should as you show. Of course, I don't see an edit post button, so I can't edit that!

Electrodynamic,

Didn't get your e-mail, but that was around the time we upgraded spam filters. Can you send it again?

On to the topic...

Spiders are pretty much made out of cloth (linen, poly, Kevlar, etc) and are heat-set to their shape. Basically a big hot iron with the proper shape comes along and clamps down on the cloth (from both sides), and permamently sets the shape (also trims the spider as well). Then the spider is dipped in phenolic (plastics). Different phenolics give different stiffnesses, as does multiple dips.

A flat spider has a curved Cms shape; a progressive spider has a flat Cms shape. And of course there are some other approaches such as that done by Nuway where they laminate two flat spiders together at the center (a large one and a small one), and get a flat Cms curve as well. You can also play doping games, too...

As far as preferring flat response or non-flat response, most people will prefer a bit of a goose in the low end AND the high end, at least for short term listening. However, that's not to say we shouldn't design/target for flat, low distortion drivers. With modern processing capabilities, if you had a perfectly linear driver, it would be trivial to add in the desired amount of nonlinearities and distortion. This means you could have your own personal "subjectiveness" knob. Dial in your preference!

As far as the ripples in the Brahma curve go, typically changes less than 3-4% in the BL curve are irrelevant; the ripples are in the 1-2% range, and really don't affect THD to any significance. It's pretty much below the threshold of audibility, so we chose to leave them in there to gain a few mm of extra linear excursion. Tradeoffs, always tradeoffs!

Dan Wiggins
Adire Audio

 

im gonna take this idea i had and run with it some more.

i have my 15 thats identical to my 10 other than Sd...lets say the Sd of the 10 is exactly half of the 15. that means that vas would be 1/4 as much.

say i want to get that back though, so i use 2 10's. due to the vas, the 2 10's would take half the box size of the 15, would they not? or i could put 4 10's in the box the 15 takes, and have 2x the linear displacement for 3 dB gain by doubling Sd, plus another 6 dB by being able to feed it 4x the power, correct? or is this all just creative math because i missed something?

eric

*edit* dan, the edit button costs ya 5 bux right now...as of next month itll be 10 bux. sorry for the shameless plug for mike...just trying to help ya brotha out! :spam:

 

Yeah, I think that most of us prefer (what we tend to think of) a flat response in our systems. But like Steven said, I think we all add our own EQ/level adjustments to suit ourselves. I do like drivers that have very low distortion and hold that low level throughout a good bit of the drivers total travel - which is why I like XBL^2 so much. XBL^2 also keeps down something that I pay attention to, Mms.

It's really neat to see things change recently in the speaker world. A few years ago progressive suspensions were understood to be used on vented drivers, not drivers suited for sealed enclosures. Technology has allowed us to harness a progressive suspension for linear suspension 'curves' in drivers that work well in sealed and vented enclosures. It'll be neat to see how things prgress beyond where we're at now. *I do know that one of the big things holding a lot of us back are baskets* They simply don't allow enough overall travel and they limit our spider sizes.

 

yeah... its been intresting to see what various companies have tried to do to better suspension travel allowed by the basket. you have the memphis LVS double basket... which seems to have done nothing, maybe the double basket was for some other reason, but i thought it was for suspension reason.

and then of course, the switch from the venezualean/4 spoke(sp?) to the 12 spoke basket.

and my favorite... the basket designed by JL for the W7 line. Just an all out awesome designed sub from what i've studied... i'm sure it has drawbacks (other than price)... but that basket allows for sooo much travel, and a horribly oversized surround isn't used that would cut down on sd.

i think in the future the basket will take a much different look in order to accomidate better excursions.

 

i have a feeling itll resemble this...cuz they can get more throw in about the same depth basket. down side is cost on machining. what im referring to, is putting the motor up INTO the basket...otherwise theyre gonna have to get really creative. hopefully creative wont mean ultra pricey

eric

 

It really doesn't matter if they make the basket to where the motor can go up inside of it. It's a cool idea though Nizzy. All that we need is room from the top of the top plate to the spider landing(s), and room from the spider landing to the cone. JL's basket and "Eclipse"s basket (they supposedly have it protected for in-car use) are the two highest excursion baskets I know of. Well the new Aura baskets are pretty incredible also, but they have their company name IN the basket. Actually their new subs are flat out awesome.

 

Just wait a few more weeks...

Dan Wiggins
Adire Audio

 

I'll be taking pictures of anything that I'm allowed to. :lol:

I'll put a page together of interesting stuff, this is highest on my list, personally. The suspension is the part that intrigues me most.
Hopefully Dan will let me poke and prod at it a little.

 

yeah... i got to talk to Chris B of Adire this summer, and man... of the parts in this new sub.... Altho i'm very intrested in the basket, I'm mostly concerned with the construction of the Spider & surround. If this new sub is more than just a SPL giant, and is actually somewhat geared towards SQ, i really wanna see the surround & spider, cause dang, how do you make a surround that can move in a linear fashion for such a "long" throw???
baskets are easy enuf to make... cost you a bunch to start off with, but its just a money issue.... suspension seems to be a bit more... takes some thought.

 

I can picture a couple options...
Don't know if they'd work in reality...
But picture a double-swinging door hinge, like on old-school cowboy saloon doors... just picture it's motion, and apply the motion to a surround, if you can picture what I mean. B)

 

Well isn't that kind of like how a progressive spider works already? It's similar to 5 or 6 hinged doors each with a specific stiffness on the hinge.

I can't wait to see it either. I know the spider is supposed to be something spectacular. And I am curious how they got a surround to move that far.

 

Chris,

Take all the pictures you want... We'll have one running, and two in "pieces" to play with.

Dan Wiggins
Adire Audio

 

i was under the impression that it(the spider) had to do with the materials used... but might be the design/shape as well. man, i'm sure we have all heard the #'s they got outta the 6" spider of the NEW design.... just amazing.

i wonder if it'd be possible to make a progressive spider made out of an elastic like material.... progressive not only in terms of the ripples, but also in the density of the weave of the material.... wonder how that'd work, or if it'd really be possible... I know elastic isn't a good idea, but if the weave was changed, who knows, might be possible.