# DD vs. XXX



## sonikaccord (Jun 15, 2008)

Ok, I am having a dispute with a member from another forum. He says that dd is ONLY made for spl and can't sound good at all and that the xxx can't be compared to it.
So my question is, can the dd(any series) keep up with the xxx(old) in sq and spl?


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## 89grand (Nov 23, 2006)

Which series of DD subs? They make a lot. Some are geared toward SPL, some aren't.

I would imagine they have a series comparable to the XXX.


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## sonikaccord (Jun 15, 2008)

im guessing that the 3500 would be comparable.


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## 89grand (Nov 23, 2006)

I'm not really sure. I don't know that much about DD subs, but the XXX is considered by many to be a great subwoofer.


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## tristan20 (Nov 28, 2005)

XXX for the win, only the 9515 is comparable for output. THe RE XXX sounds very good for a loud sub. One of the best Loud and good sounding subs around.

If you wanted loud with high spl and you have the space go with the DD
If you wanted loud and clean with a smaller box go with the XXX

Both handle around the same power


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## CAMSHAFT (Apr 7, 2006)

DD ---> I have a lot of respect for even the bottom line....


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## el_chupo_ (May 27, 2007)

Im guessing your debate is there, but ca.com is probably more suited to this discussion. Alot of people there run DD and the XXX. Its where I first heard of the XXX


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## tard (Jul 13, 2006)

anyone who says DD is just a fart cannon or spl sub is just a parrot spouting what they've heard with ZERO real world experience. they don't know WTF they're talking about. or else DD is their competition and they're purely being bias. (i've seen several "ca.com guru's" in their tests make these spl only claims) one more would be someone who isn't familiar with DD and their box/ installation wasn't savvy to DD's real world R&D'd intent.

the XXX and any of DD's line are apples to oranges.

just throw out any arguments that the XXX is going to sound better because it has more linear output and it has XBL technology. that BS is just a used car salesman pitch. it has it's time and place, but no one part is going to make it superior. it's going to come from all the parts together, with the tuning of the spider carrying the biggest end result for real world performance.

that being said, the XXX has a stronger bottom end in the lowest octave, but won't have the transient kick or the upper end the DD has. generally speaking, cause you can degrade DD's typical qualities depending on the box and application design. the XXX might have the feel of being "smoother" because of the transient kick DD's have. 

is there any that can keep up in loudness? DD has the most SPL records period. people used the MT to achieve RE's SPL records, NOT the XXX. right now alan dante is the loudest in the world using only 2 DD subs vs some of the other top competitors who have 8 times + as many subs.

for SQ, DD has the 9100 that is geared for sq. i can't give any first hand input on it, i haven't ever even seen one in person. that and a 99z. but from my personal experiences with the DD team, i have no doubts in it's performance. as for the 500 - 9500, they all sound darn good. 

but at the end of the day, it would come down to application and personal preferance dependent for what would sound better.

also, DD's take a very, very long time before their suspension get's broke in and they will change some in how they sound.


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## tristan20 (Nov 28, 2005)

BTW Alan dante can throw anysub in his car and he will hit very big numbers
He uses 1 DD sub, but NOTE that sub cannot play music. Its a ONE TONE SUB

There are positives and negatives to both subs. But from personal experience I can tell you that the DD is loud in a very big box. The XXX will get almost as loud in a box about 3/4 the size.

The 3500 series of DD is geared toward the SQL market. But I have yet to hear a 9500 sound as good, well I mean with a direct comparison to others that I have heard. Both subs are great I guess its best if you demo a set and see which sounds better to you.

Different types of music, different setups, power, car. It all comes into play.


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## bassfromspace (Jun 28, 2016)

tristan20 said:


> BTW Alan dante can throw anysub in his car and he will hit very big numbers
> He uses 1 DD sub, but NOTE that sub cannot play music. Its a ONE TONE SUB
> 
> There are positives and negatives to both subs. But from personal experience I can tell you that the DD is loud in a very big box. The XXX will get almost as loud in a box about 3/4 the size.
> ...


I've heard that IB 9500's are monsters.


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## thehatedguy (May 4, 2007)

Alan is in Ext2 now. And the Z series subs he uses can play music, his car probably can't.

I have a friend who is both a DD and a RE dealer, and there is no doubt in my mind that DD builds a better speaker than RE. I've owned a DD9512b, and it was a really GOOD sounding subwoofer.

And the DD 1508s...what little beasts they are.


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## tard (Jul 13, 2006)

thehatedguy said:


> Alan is in Ext2 now. And the Z series subs he uses can play music, his car probably can't.
> 
> I have a friend who is both a DD and a RE dealer, and there is no doubt in my mind that DD builds a better speaker than RE. I've owned a DD9512b, and it was a really GOOD sounding subwoofer.
> 
> And the DD 1508s...what little beasts they are.



the brother has a witness to all of that.


also, alan has tested many other brand subs via direct drop in, aside from making different baffles to fit different sizes. 2 fold reason he sticks with DD is that they are louder and the others drivers failed.


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## Oliver (Jun 25, 2007)

Sound quality


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## Hillbilly SQ (Jan 26, 2007)

a$$hole said:


> Sound quality


holy ****

i've been wanting to try a 3510 in a downfired ported box. would have to at least double the power on my sub amp though as it's only 400rms. i'm sure that power would get a ported 3510 moving good enough though.


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## sonikaccord (Jun 15, 2008)

That thing looks like a beast. He said because of their high fs, they would sound like crap in a low tuned ported box, and that they cant play frequencies below 35hz with authority. I was just thinking wtf is this guy on. I wish I had some real world experience with dd subs.


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## ClinesSelect (Apr 16, 2006)

a$$hole said:


>


LOL There is a better photoshop of that out there somewhere. DD 1508 on a Z motor. 

My 3512 certainly plays low end with authority as did my 9510 and my Audioque HD310 (the pre-overseas built version that came from the DD buildhouse).


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## Sassmastersq (Jan 12, 2007)

from what I've been told, the 9500 series are VERY good sounding subs, not just SPL monsters... in fact, most SPL monster subs sound good, because they absolutely have to reproduce the signal fed into them linearly and accurately because the measurement systems respond better to a clean sine wave than to a square wave or a flattened sine wave.


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## thehatedguy (May 4, 2007)

Well, truth be told the SPL guys are clipping the amps some to get more power out of them. The monster SPL subs can sound good (if they don't have a Fs in the 50-60 range) because they need the motor strength and a stiff cone to keep from buckling from the power and pressure. Also most aren't concerned with working in super tiny sealed boxes either, so you can get some sensitivity back that way too.

I personally haven't liked any RE subs that I've heard.

I used to play 20 hertz tones wide open on my 9512b in a box tuned to 35 and 45 hertz and the speaker never approached bottoming out. It was/is one of my favorite all around subs that I have owned.


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## Neil (Dec 9, 2005)

tard said:


> just throw out any arguments that the XXX is going to sound better because it has more linear output and it has XBL technology. that BS is just a used car salesman pitch. it has it's time and place, but no one part is going to make it superior. it's going to come from all the parts together, with the tuning of the spider carrying the biggest end result for real world performance.


The Pre-06 XXX has measurably lower distortion than the 9500 series, which are often compared. That is a typical by-product of successful XBL^2 implementation, and that's why people use that argument.

The most damping is provided by the motor, and most distortion is generated by the motor. The suspension is, in my opinion, a secondary concern.

Which sounds better? Dunno...I couldn't tell you what you'll like better. I personally prefer the XXX over every DD I have ever heard, though the 9100's aren't bad.


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## tard (Jul 13, 2006)

Neil said:


> The Pre-06 XXX has measurably lower distortion than the 9500 series, which are often compared. That is a typical by-product of successful XBL^2 implementation, and that's why people use that argument.
> 
> The most damping is provided by the motor, and most distortion is generated by the motor. The suspension is, in my opinion, a secondary concern.
> 
> Which sounds better? Dunno...I couldn't tell you what you'll like better. I personally prefer the XXX over every DD I have ever heard, though the 9100's aren't bad.


i'm with ya on which sounds better. it's a matter of application and preferance.

but as far as "measured specifications", all that can go right out the window. on paper specs and measurements are like some one bragging about having a black belt. what good is that if they can't successfully fight worth a darn in the real world. moral of the story- i'm more concerned with how it performs to the ear and specs aren't always an accurate represntation. i have to disagree on the importance of spider tuning. from way back in my early years reading the works of vance dickason, to through the years talking to (and blessed to being taken under the wing of one) guys who R&D and build, they all say it's in the spider.


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## Neil (Dec 9, 2005)

tard said:


> but as far as "measured specifications", all that can go right out the window. on paper specs and measurements are like some one bragging about having a black belt. what good is that if they can't successfully fight worth a darn in the real world. moral of the story- i'm more concerned with how it performs to the ear and specs aren't always an accurate represntation.


I care about being accurate to the source, so no....none of that goes out the window. How it performs to the ear is the same as how it measures, though there may be a gap in your perception. It is the ear that is fallible, not the measurements, and once you understand how you perceive, it becomes clear that what you mistakenly call "specs" are, in fact, the only accurate representation. If you prefer the qualitative, I guess that's your choice.

For the sake of clarification, only the last three "you"s are specific to tard. The rest are not intended to be presumptive.



tard said:


> i have to disagree on the importance of spider tuning. from way back in my early years reading the works of vance dickason, to through the years talking to (and blessed to being taken under the wing of one) guys who R&D and build, they all say it's in the spider.


Any supporting evidence or anecdotes from credible sources? A look at the mathematical Q relationships of BL, Mms, Cms, etc. clearly shows that the motor is the dominant aspect of damping; similarly, it has been well understood for a few years now that the dominant source of distortion is the motor. The empirically accepted breakdown of distortion is roughly 60% BL non-linearities, 30% Cms non-linearities, and 10% Le non-linearities.

edit: Just to further clarify....you make it sound as if these measurements are not real world...in fact, this is real world phenomena being measured. These are physical quantities that actually exist. From there, you are left with two major factors: 1) the listening space (which again can easily be quantified), and 2) human perception. Of course, we can never develop a model that will support every human, so we develop perception models that suit 90% of all humans. It is this last factor that we don't completely understand yet, though some are silly enough to believe that their ears are the best way to measure what is actually happening.


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## Oliver (Jun 25, 2007)

Neil  hope this helps make your point !

quote>
Now...if you look at the parameters for 99% of the speakers that are available you'll see that the Qms is always MUCH higher than the Qes. That means that the suspension allows MUCH more overshoot than the motor. Thinking a little further, you'll discover that what that really means is that the MOTOR controls the motion of the cone and the suspension contributes very little control. Both the motor and the suspension work to overcome the inertia of the moving MASS. The motor does a better job than the suspension. essentially, the suspension screws things up. The suspension is there mostly to keep the coil from leaving the gap and should be designed to apply very little force until that is about to happen.
end quote>

Of course he could be talkin bout 1 % ers


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## tard (Jul 13, 2006)

i passed on the info, i don't care if you stick to your preconceived notions or not. you will reject anything i have to say, so why waste my time? i started out with the paper jockey mathematical tunnel visioned mind set too. but i'm confident with what i've learned and where i stand, i don't need to try and prove it to anyone. take it or leave it, it's your loss or your gain.

my only comment is; IF you really want to learn the deeper aspects, then you can start doing the research i did a long time ago. pick up some of the technical works of people in the industry. get into periodicals that those in the industry publish their works. start contacting and talking to those in the industry who actually design and build the better speakers in the industry. if you're lucky enough, spend some time with them while they are currently in a new R&D project.

if you have the approach of being a hobbiest audiophile, looking to learn, and willing to listen to what they have to say (even though it is against the grain of what you think you know), willing to travel hundreds and hundreds of miles and spend a few days at their facility, you can find some people willing to share and show you a whole nother side of the fence.

BTW- different engineers will have different philosophies. each can be different and argue with the other about who is right. but each is very good and proven at what they do. learn from each of them and they all deserve respect.


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## Neil (Dec 9, 2005)

tard said:


> i passed on the info, i don't care if you stick to your preconceived notions or not. you will reject anything i have to say, so why waste my time?


What gives you that _preconceived notion_? All I've asked is that you provide information that supports your ideas.



tard said:


> my only comment is; IF you really want to learn the deeper aspects, then you can start doing the research i did a long time ago. pick up some of the technical works of people in the industry. get into periodicals that those in the industry publish their works. start contacting and talking to those in the industry who actually design and build the better speakers in the industry. if you're lucky enough, spend some time with them while they are currently in a new R&D project.


Forgive me for asking: what makes you so certain you are so much farther ahead of the curve than I am?

Though I speak with many in the industry (as is natural when writing for AudioJunkies) and already read daily on the subject, I don't need to point any of these things out to make my original point. The work done by industry leaders stands for itself, on its own merit, and directly refutes what you've suggested.

Need to understand the components in distortion better? I recommend reading some of Klippel's AES papers.

Need to understand the limits of perception better? I recommend reading the GedLee AES papers.

Need to understand the mathematical derivation of Thiele/Small parameters better? I recommend reading any of the work that led up to what is now called the Thiele/Small parameters. That includes anything from Rice & Kellogg, Olson, Beranek, Novak, Thiele, Benson, or Small.

With all due respect, you should know the person you are speaking to before assuming their experience. The points you wish to make could easily be refuted with factual data or anecdotes from respected practitioners (as I requested), but perhaps it is easier to stick to character assassination (as you chose).


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## Kmanian (Apr 8, 2008)

I jsut want to throw this in to the mix. If there is anyone with the knowledge and lack of bias that is fairly close to Nashville, I have a 15" RE XXX & MX, a 12" DD 9912, and a 12" Critical Mass UL12. I would be willing to let them test them "real world" and give a unbias report.


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## tard (Jul 13, 2006)

Neil said:


> The points you wish to make could easily be refuted with factual data or anecdotes from respected practitioners (as I requested), but perhaps it is easier to stick to character assassination (as you chose).


i have not attacked character, that is what someone does when they can't refute the information. the vibes i got is that it would do me no good to discuss this issue. the way i took it is that you are stuck on only focusing on technical data.

i know the mathematical formula's, test data, and all the rest. you act like i have said none of it is important. it has it's place. in my stand point it is secondary, and yours it is primary. am i reading this wrong?

i don't listen to a speaker with my eyes on specs, plots, graphs. there's many trade offs and sacrifices that may not be appealing to the eyes, but are negligible to the ears to gain in other areas.

i didn't discredit your knowledge, it's easy to see you have a good book smart understanding of things.

and i do have a problem with T/S specs when they are taken with minimal input signal. this does not represent the hard dynamic conditions when being played where most people listen. even dickason makes many comments about this and other inaccuracies in his book. another example is in regards to ported box designing.

if you want some other examples, one time i commented that a guys speaker didn't RTA flat. at that time i was a proponent of flat RTA, it was appealing to the eyes and to the idea that the speaker should more accurately produce all sounds on the appropriate level. his response was that he wasn't concerned with a flat RTA, you can EQ out some of that later. if producing a flat RTA plot sacrificed some of the dynamics and true to the real source sounds, it was an acceptable trade off.

believe me, it took me a couple years for it all to sink in and get away from going purely by the book.

i'll just keep it simple and use a readily available philosophy, from Jassa. he is not the only builder who has this outlook. it can be different in a few places than atwell, stomplier, mike (i forget his last name, of shocker who did some work for earth quake) etc, etc.. it's like ford, dodge, chevy, each has their own engineering philosophy and each works for how it is intended.

below, the "years of experience" is part of the description by dickason as the "art" in speaker building. it's not just a science.


from DD......

Research and development strategies follow many paths in the making
of a product. Many firms rely on computer modeling programs to cut
down on the field development time for a product. Many firms strive
to develop drivers with favorable box building specs as per what models
out well on computer simulations. The best computer models do not
take into account all the variables in vehicles, music tastes, volume
levels, power levels, EQ settings and the effects of testosterone have
on final system design.

At DD, we use real world testing as our primary R&D tool, not simulations.
We have extensive help from end-users and dealers whose input
defines target box sizes and power levels. We use computer modeling
combined with years of experience to design the starting point woofer
specifications. These woofers are built and field evaluated under the
exact conditions the final products will see. We take what is learned
from each trial batch until all design goals are met.

These beta versions are then tortured under the harshest duty cycle
tests, again in real cars, with real music with real power.

Once all the listening tests, field trials and reliability testing are complete,
we run T/S parameters. These parameters end up where they end up
based on real world performance. We do not take box simulation
programs into account in our final design. The sound of the speakers
in their target enclosure size while being driven with real power levels
determines where the parameters end up. If our parameters happen
to model well on the program someone uses, it’s purely by accident.

*Although speakers can be broken down to all their various parts, and features can be described, explained and analyzed, a speaker is more than the sum of its parts. A speaker, or any product, is an idea or concept brought to life by someone or some company. That idea or concept is shaped by the elements that go into it, each contributing to the total performance. Much like a high performance engine, one performance feature helps another, which in turn helps another. The cumulative effect is more important than any singular component.*

(my personal translation note- the real world how it sounds is more important than any specification test data or design feature)

That funny looking wavy thing under the cone is one of the most crucial components to high performance loudspeakers. The spider keeps the cone moving straight up and down, keeps the coil from moving side to side in the magnetic gap (the death dance for a speaker) and provides restoring force to the cone movements by acting as a spring. We don't use progressive roll spiders so you won't have to worry about your speakers sagging after a little use. This spider topology offers poor coil control and loses what little control is has after being stretched out.


and a few real world examples. the Scan rev 4.5" didn't rate great in zaph's data review. but we know in the real world that it is one bad mother. or the HAT L3 didn't klippel good and had many people here nervous about their order after they saw the data. but then every single one of them commented how good the driver sounded and they could not even notice the distortion they had seen in the graphs. this is my stand point. 

i use a speaker for how it sounds, not how good it looks on paper. not how well it meets on paper standards we have been taught to believe makes one speaker sound superior to another. if lot's of odd order distortion is what it takes to give a warm fuzzy illusion of feeling the air blowing out of the sax right in front of me, i'll take an extra serving of distortion please. if a non-flat RTA is what it takes to make the snare drum feel like i am standing right next to it, i'll take a speaker with an RTA that looks like the stock market graph for the last year. if the better sounding speaker happens to be the one that is most appealing to the eye also, great, i'll use that one.

audio is a listening sport, how it sounds is all that is relevant in the end.


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## Oliver (Jun 25, 2007)

Tard , have you ever heard of Dumax ? or Klippel ? 

Maybe you could visit....say "Neil", and watch him perform some klippel tests [ after you explain to him what he will see and hear ].{That's not represented by specifications }

I'm thinking of buying a motor in California [ something cheap from a salvage operation, then getting a picture of Stephen Mantz next to it and selling it as a "Just like superchaged LT-1" ].

around here everyone seems to think if I put a amplifier made by some company in a sentence with S.M. that it is just like he builds his


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## tard (Jul 13, 2006)

no, never. not FEA, LEAP, or any of the others either.

how about instead of me watching neil run some tests, i audition a speaker you and him have built that competes with some of the other best of the best.

shouldn't be hard. since you say the suspension has so little to do with how it will sound. 

oh wait, i forgot. just send me a klippel test or design simulation instead. speakers aren't meant to be evaluated by the end result of how they sound.


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## Oliver (Jun 25, 2007)

tard said:


> no, never. not FEA, LEAP, or any of the others either.
> 
> how about instead of me watching neil run some tests, i audition a speaker you and him have built that competes with some of the other best of the best.
> 
> ...


Thiele and Small test small signal parameters {maybe up to 20 or 30 watts }.

A Klippel machine is like a Dyno that is used on cars [ drop the pedal and go, all the whilst recording the info ].

yes how they sound is really all that matters in the end 

If you want to believe that the suspension controls your speaker "All of the time", who are we to say otherwise


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## Oliver (Jun 25, 2007)

Kmanian said:


> I jsut want to throw this in to the mix. If there is anyone with the knowledge and lack of bias that is fairly close to Nashville, I have a 15" RE XXX & MX, a 12" DD 9912, and a 12" Critical Mass UL12. I would be willing to let them test them "real world" and give a unbias report.


You pay to ship them to Canada, and I'll bet they post up the results of the tests and even give you a copy of what they found 

{Please check with Ant first {owner and operator of this website and a Klippel machine }, good luck !!]


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## Oliver (Jun 25, 2007)

tard said:


> no, never. not FEA, LEAP, or any of the others either.
> 
> how about instead of me watching neil run some tests, i audition a speaker you and him have built that competes with some of the other best of the best.
> 
> ...


tard in the past, NPDang tested an Aura 12" sub { one of the best sounding subs/period }.

The specifications and the real world Klippel test weren't in agreement on how much BL there was [ "Oh, and it caught on fire 3 times ]

But , what the hell do you expect for around $600.00 apiece


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## tard (Jul 13, 2006)

a$$hole said:


> If you want to believe that the suspension controls your speaker "All of the time", who are we to say otherwise


i did not say that. 

would that be an aura sub that smith and turner were involved with producing when they were with aura, before the chinese bought them?


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## Oliver (Jun 25, 2007)

tard said:


> i'm with ya on which sounds better. it's a matter of application and preferance.
> 
> but as far as "measured specifications", all that can go right out the window. on paper specs and measurements are like some one bragging about having a black belt. what good is that if they can't successfully fight worth a darn in the real world. moral of the story- i'm more concerned with how it performs to the ear and specs aren't always an accurate represntation. i have to disagree on the importance of spider tuning. from way back in my early years reading the works of vance dickason, to through the years talking to (and blessed to being taken under the wing of one) guys who R&D and build, they all say it's in the spider.


Tard, I know you didn't say that !

Without all the components of a speaker being designed for a purpose, what have you got !?

Lets leave the spider on the speaker , Ok :blush:

Now let's change the cone and surround and motor, see where this is going


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## Oliver (Jun 25, 2007)

Use the right tool for the job


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## tard (Jul 13, 2006)

a$$hole said:


> Tard, I know you didn't say that !
> 
> Without all the components of a speaker being designed for a purpose, what have you got !?


one that works, but not as good as one that has all its parts dialed to work together.



a$$hole said:


> Lets leave the spider on the speaker , Ok :blush:
> 
> Now let's change the cone and surround and motor, see where this is going


if you're saying that by changing any of those components you can change sound charictaristics, yes. or on the side of what you and neils argument has been, yes you will change the measurements. i don't disagree to any of that, and it's all a trade off. polymineral cone, paper cone, magnesium cone kevlar, foam surround, rubber surround, gap changes, etc, etc, spiders have to be tuned to do their job to meet these changes as well. example would be pushing the cone down on a W7 vs a DD 9500. big difference there. they all play their part and have their pros and cons. 

i don't think we will ever have a perfect speaker. you're always going to have to rob peter to pay paul somewhere. which brings me to your 2:28 post that says my whole point from the beginning. how they sound in the end is all that matters.


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## Dangerranger (Apr 12, 2006)

Objective measurements are very useful *when and only when* the implementation is taken into account. 

Before I delve into my opinion on the two, I'm gonna give my opinion overall on these kinds of comparisons: *Most* people that dig deep into this kind of stuff aren't even the ones looking for extreme SPL (150+). Most would be satisfied with mid-130s maybe 140s and good SQ to go with it. If you can't accomplish these rather common goals with one or two decent subwoofers, by decent I mean "midlevel" with relatively moderate power levels by today's standards (say 800W on a pair), you have no right to argue because you more than likely haven't realized the potential of what you already have. If you've met the above requirements and still aren't satisfied with the output you're getting, you don't "need" a subwoofer with 40mm of excursion to accomplish your goals, you need to learn how to design and build a subwoofer box, and how to implement it in your vehicle's environment. Period. Don't get sucked into snake oil, typical audiophile snobbery and bandwagons. Research, design, and build to what YOU want and need to get the job done. You're doing the company you bought from no justice if you don't do everything possible to optimize what you have. If you've been that guy that got pissed because somebody else's single 12 got louder/sounded better than your two, and he doesn't own something like a Honda CRX, you have no business talking about what gets loud, what sucks, or "personal experience". Some vehicles are crap environments but most aren't *that* much worse than others.

Onward.

Digital Designs subs are engineered to extract pretty much every ounce of potential they can out of the ported applications that they specify. This benefits you and them two-fold. They don't follow trends, they don't go by what the people think they want, they engineer subs to a proven formula that they have been very successful with. No guesswork, stick it in "x" box, ports "x" long, and let it roll. They don't claim or market subs that are some jack of all trades, optimized for "both" (aka: neither) sealed and ported enclosures, they just build what has worked for them. In the end, they know what they're producing, you know what you're buying, take it or leave it. Eliminates a lot of potential negative feedback because it cuts down on the joe blows out there that could mess up a wet dream if they wanted to. 

The XXX is the all arounder. It has a long stroke, effective motor design, lower Fs, etc. It is essentially a good subwoofer for a sealed box application where you don't have the space to go with a large ported box or similar. It will work pretty well in a ported box, but still not as good as a more efficient subwoofer.

Realistically, there are different requirements for different enclosures. You can't make blanket statements about x sub having less distortion than this sub because the testing methods usually don't take the enclosures or the environment effects into account. The speaker will operate parallel with the enclosure. Objective testing is useful, but only if the one interpreting it realizes HOW to use it.

Neither spider design is ideal. Both are good for their intended use. DD uses linear spiders, which resemble a 2nd order non-linearity that gradually tapers off, and is a good thing to have when you're below the tuned frequency and lack control from the enclosure, ported boxes aren't as predictable or linear as sealed. RE uses a progressive roll, which is pretty compliant and linear in it's linear region but tends to be a higher-order non-linearity once things get out of hand, which works good for sealed boxes because you want to rely more on the consistant pressure of the air spring in the box rather than the suspension anyway.

Likewise, DD's motor design is also optimized for ported. It's closer to an evenhung design which isn't the most linear, but linear where it counts. Ported boxes have much more mechanical control around tuning than sealed and they only really need enough excursion to get the output desired without sacrificing a ton of efficiency, and enough linear excursion to allow the sub to maintain control when you're below the tuned frequency. It's a compromise, you don't want the sub to bottom out, but you want to design an efficient subwoofer that gets low enough and doesn't sacrifice efficiency for excursion that won't be used. This is a compromise that DD has figured out pretty well in car audio applications.

RE's design is linear, optimized more for sealed. Sealed boxes have a fairly linear air suspension, they don't have the mechanical control that a ported box does around tuning, but they do have more consistent behavior, aka the subwoofer's excursion gradually increases as the frequency goes lower. The XXX has a low Fs and fairly low Qts for good low end output from a relatively small sealed box. To get that, they had to effectively add mass in order to get a lower Fs (or a softer suspension). To get said excursion, the rebates for the XBL^2 motor had to be extended out far, making the motor closer to underhung characteristics, which is why the sub isn't exactly renowned for it's efficiency (flux density is spread across a wider area, hence less BL strength being focused at center position).

Put the horses to their courses, then evaluate . The XXX is a good sounding sub, but I'd put a 9100 series against the older XXX in the right application.


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