Experienced Numbers

I do regard most of the opininions on internet forums. If it is just one person who reviews a product, I find it somewhat harder to believe whether I would like it or not. But when a HUGE majority of the owners give praise and have no complaints, such as with CDT components for example... I think you will find it hard to go wrong.

BUT... this is where it comes down to personal preference. People with experience can recommend good drivers that will go loud with out distorting, and have good power handling, good crossovers, ect. ect. But personal preference comes into the picture as far as whether a person likes their speakers to be bright, warm, strong midbass, ect. I tend to believe the opinion of the general public though, everybody thinks Focals are bright and CDT's are warm... the entire forum public who has heard these speakers probably wouldn't dispute it, you can take it to the bank.

As far as people considering DD's a SQ sub... that all depends on what forums you go to. You can usually tell by reading a person's posts and seeing the way they carry themselves whether they know what they're talking about or not, and there are particular forums who probably have a larger amount of 'unenlightened' people, as well as forums with more of an SPL member base and so forth...

And on the more experienced forums, people are going to sniff out a bad install right away... if somebody came on complaining that thier well-known top-brand speakers sounded like sh!t, the first question asked would be how they were installed.

 

The parameters are often misunderstood, which is no fault of the parameters themselves.

Parameters are simply discrete measurements...
Each measurement is just that, a measurement, of something...
Just like with any measurement, "it is what it is".
People get into trouble because they try to misapply the measurement.
Consider this statement:
"Wow, that guy is 6'8" tall... he'd be great for our basketball team!"
No... all 6'8" tall is is a measurement of height.
Yes, 8 or 9 times out of 10, that conclusion might be correct.
But, when you found out that guy that was 6'8" tall also weighed 650 pounds... do you reach the same conclusion?

Almost all people who tout "specs don't tell you anything" don't understand them all, or are misapplying them, or simply taking them too far in application, like the basketball player above.

Also, parameters really can (or I should say could) tell the whole story, certainly at a minimum giving good clues as to how it will sound.
But, we don't measure everything, for one...
Even if we did, the enthusiast would have to understand all the specs...
...and how they interact with each other.

The DUMAX and Klippel BL and suspension curves (and Klippel does a bunch more actually - it's modular, and I'm not familiar with all the possiblities) are a real breakthrough.
Before, modeling tools assumed everything was linear. Xmax was given in terms of motor excursion, and it assumed that suspension was linear within that range (and back then, it easily could be... Xmax of 10mm was pretty big)... and assumption is always bad.
Particularly when the majority of IMD distortion comes from BL nonlinearity, essentially... and I would also picture this effectively having the same effect from a suspension having it's effect on motion, in turn having it's effect on the motor.

One thing that we don't measure - and again "assume" that it's not present - is cone breakup modes.

There's lots of things that we do and don't measure...
Don't discount them - they are measurements!
To discredit the measurements is like saying "Ah, that ruler doesn't mean anything."

Try to pull this one in your town:
"Ah, Officer, that speedometer doesn't mean anything. I could tell I wasn't going that fast."

It just doesn't work that way.
But it would be accurate to say that your speedometer wouldn't allow you to reach conclusions about your fuel mileage - at least not without another measurement tool - your watch - and even then, lots of work and translation.

 

This is actually a great reason that specs ARE so valuable.

A person's opinion is ALWAYS (and only) based on their past experiences, and where a particular product stands up in their experience.
Also, you can't ever hear a product in isolation... you always need a whole signal chain, and in car audio, an installation and particular car interior, that you may or may not be familiar with.
All this colors those experiences.

And everyone thinks their experiences were valid.

In the end, you almost have to discount almost everyone's experiences, except those you know you can trust... ain't that a bitch? :lol:

Seriously though, if all you've ever heard are flea-market setups, and SPL setups at your local "bass-off", or the high-school parking lot... then of course, a DD sub could sound like the best, most accurate, tonally correct thing you've heard.

But someone who's grown up in the home of a lifetime audiophile, who had a true SQ setup in their house, and now is shopping for one for their car, they'd feel misled if they took the advice to pick one up for SQ purposes.

On the other hand, all the specs for the subs - including BL curves and suspension plots - they are neutral like Switzerland.
They are measurements... an SPL sub will tend to look a certain way, and a SQ sub will tend to look a certain way.
Ported box subs have specs that show that, and sealed box subs have specs that show that.
Subs that play low have specs that show that, while those optimized for higher efficiency have specs that indicate that.

Don't get me wrong, there's enough that's not measured that you really do need to listen to things to get "the whole picture"...
But the specs can certainly lead you to narrow down your list to a few final contenders.
And any subs you scratched off your list, you did so by objective reasoning...
Yes, if you scratched the DD 9515 off your list, someone still might come back and say "that sub has great sound quality!"
...but that's relative to their own experiences and personal standards.

 

Numbers, specs, blah ,blah, that means nothing to me. If it sounds good to me, that's all I care about.

What's the fun in spending money on asomething you know is good and plugging it in an application that you know will work? I see things in a different perspective and like to take "junk" and make that work well.

Now I don't do this all the time, but that's the fun part of car audio to me.

 

But in order to do that, you need to know something about it.
You can't just go in blind, or you'd waste a lot of time and effort trying a small sealed box.. then a large sealed box.. then a small ported box... and a large ported box... and maybe something in between... and just trial-and-error'ing it until you "happened upon" something that you concluded (based on nothing but several random trials) was "best".

On the other hand, you could look at some specs, and at a minimum determine first if that sub was more ideally suited to a sealed or ported application.. things like Qts and Fs.
You'd never take a Cerwin Vega Stroker and seal it, for example. :lol:

In order to reach those goals, you are using the specs, right?
Modelling tools - that's ALL (100%) spec-driven simulation.
And that's what you use, to "take something and make it work", right?

 

You are correct, but I do not take into consideration what most people think "look good" or "models up well."

I love readin things on the net like, "I just bought ABC driver and it is a piece of crap." Makes me want to get the driver and see if I can make it sound good. I'm just a tinkering person.

 

This is why it's been nagging at me a bit lately to get to know the T/S parameters a little better. It would be nice to be able to look at a driver's spec's and get a genreral idea of what it's good for.

 

Check out the "George" topic found above. Dan Wiggins has one of the best breakdowns of parameters I have ever seen. [/b][/quote]
Will definetely check it out , sounds like it's just what I've been looking for.

Have read a couple of posts by Dan about T/S parameters before, always very in-depth. Never saw a complete overview of them by him before though.

 

I like a combination of both. Numbers give you a great place to start, but they don't tell you everything. Ultimately, the "perfect" driver, that plays the signal w/o any deviations in FR, doesn't sound good to many, many, many ears. Most people like a little extra "detail" in their tweet, a little extra "oomph" from the sub down real low, and a midrange that's a little "warm-ish".

Of course, the "numbers" will allow you to identify the driver that will play the signal faithfully, unfaithfully, or anywhere in between so all you have to do to is boost/cut to give you the sound you like...which is unique, usually, to your ears.

To me (harmless generalization coming...), the people who bring up the numbers (too) frequently come across as being more interested in the science that got the driver there, and less interested in if it actually sounds good once installed in a car. We should all by now that once you throw it in a car, regardless of how much modeling you do in BB Pro/ISD, the FR of the driver will/can change radically. Those T/S param's don't tell me much about the rattles, buzzing, cancellations or reflections in my truck. Also, unless the physical installation of the equipment is perfect, and the "tweaking" installation is perfect (this being setting xovers, gains, and appropriate eq'ing), what you see in a spec sheet won't necessarily be what you hear once installed. Oh yeah, once the engine is running, and wind/road noise, sirens, screeching brakes, loud motor cycles, tires burning out, loud/obnoxious engines on muscle cars, etc, start, are you really going to hear that low level detail that the t/s specs tell you that your driver is going to reproduce with no/close to no distortion?

I don't know. I'm stuck between the two. I like numbers. I also accept the "stuff" outside the numbers that have a real effect on the final sound of the driver in question


For evaluating the driver only, specs have their place. Once that sucker goes in the hell hole that is your car... :blowup:

 

The age old parameter/objective listener debate.

Wait, did I just say objective listener?

To someone who has little to no understanding what the numbers tell us, they do mean nothing. However, to someone who is so deep into the hobby as so many of us here are they tell us alot.

While TS are fairly static in nature, the rundown of how they sustain themselves via dumax/kippel etc. can tell us basically how they perform.

The people spouting off about how the Dumax and kippel are just for designers and engineers are 1 of 3 classes of people. First, the ignorant who has no idea how to take those lines and #s and determine the driver's behavior by it. Second, the guy trying to pull the wool over your eyes and sell you his inferior product. And finally, the elitest who always knows more than everyone else.

The numbers and dumax are simply the way that it is. With an understanding of what each parameter means we have a basic understanding of the drivers performance. On to the next step, with an understanding of how the parameters interact with each other, and how they affect each other we can get an even better grasp of the driver. Finaly when we learn to understand the Dumax and Kippel type readings we have an idea of how the driver will behave in a dynamic state. The amazing thing about this grasp on the parameters is that it is solid, based in fact, and no human being has any opinion on what the actual measurements are.

Simply listening to the driver or taking someone's word on it leaves us in the hands of a poor install, or an ignorant ear. Maybe not even an ignorant ear so much as simply someone with either a bias toward/against a certain product, or simply someone witrh differant taste than you. All can obviously affect the second-hand information we will recieve, and are a part of that human error the parameters avoid.

Me, I'll take objective over subjective any day

 

B)

well said big boy

 

Sure they can tell you if it has a flat FR and low distortion. You mention some people like peaks and valleys and coloration though and seem to pass it off as the params and dumax can't tell us these things, but they can. They can tell us all about a bad driver as well as a good driver.

People tend to submerge themselves in the numbers and "perfect driver" debate, and use this same arguement as to why these numbers mean nothing. Yet they ignore the things that the #s can tell us about, what may be considered, the "not so perfect driver".

Just because a driver is objectively better, doesn't mean that you will like it. But if you learn to read the #s outside the "perfect driver" you will see the pattern that develops with the drivers that produce the sound you prefer .

 

My take...

Fully characterized, with BL/Cms/Le curves, you can make some very exact predictions about the potential sound of a driver. How it actually sounds is more a function of the install, rather than the driver itself.

In other words, if the specs look promising, but it sounds bad, chances are it's a poor install. If the specs look bad, the chance of it sounding good are pretty low.

Dan Wiggins
Adire Audio

 

Exactly, and that's why I said on the other page:
<!--QuoteBegin-geolemon
Also, you can't ever hear a product in isolation... you always need a whole signal chain, and in car audio, an installation and particular car interior, that you may or may not be familiar with.
All this colors those experiences.

And everyone thinks their experiences were valid.

In the end, you almost have to discount almost everyone's experiences, except those you know you can trust... ain't that a bitch?[/quote]

People who claim to have heard "a subwoofer" haven't..
They've heard an entire signal chain, that's likely different in several ways from any signal chain that the recommendee has...
And they've heard a particular installation, which takes into account the enclosure size, design, and construction quality, placement, aiming, and the unique acoustics of a particular vehicle, which again odds are is not similar to that of the recommendees car.

I'll give you a great example:
JL Audio's 12W6's.
I've heard several installs now with those particular subwoofers, from mild to wild, from budget to high-dollar install, ported and sealed... and I'd never been impressed by them at all... in fact (being a long-time W6 owner) I was somewhat disappointed.
Then, Manville Smith gave me a long demo in the JL Mini Cooper at CES.
It was most likely the nicest car that I've ever heard.
With live music (Eric Clapton concert DVD) it was incredible, accurate.
Then, he put something with some big bass in... Blue Man Group. Wham! Huge impact, really, serously impressive.
I turned around, took a glance at the two subs, dished cones, and said to him,
"Ah, W7's, huh?"
To which he chuckled a little and said,
"Nope, those are 12W6V2's"
:blink:

I definitely agree with Dan on this one...
And I think that example illustrates that same point, too. B)

 

At what point do the numbers NOT tell us something? For instance Driver A (15") is completely "distortion free" up to 25mm xmax. Driver B (15") is completely distortion free up to 21 mm xmax, but distortion starts to show up at 21.1 mm and beyond. On paper, Driver A is the better driver (assume kms curves are "equal", induction numbers are "equal", etc...just talking about Bl|excurs. numbers here), but are we going to hear the distortion in driver B on music at normal or beyond normal listening levels? Basically, if a person can't hear sub distortion until said sub is playing at 140 dB's, does it really matter in the end? We are all "deaf" in the sub frequencies anyway...and the lower the subbass gets, the less articulate our ears become. I guess my example is kind of like the amp with .0000000000000000001% THD, and the amp with .000000001% THD. Are we really going to notice the difference, or is it only measurable on a $150,000 machine? I'd imagine there is a threshold that, once eclipsed, is inaudible to even the most golden of ears.



One other thing, if distortion ultimately shows up as frequency response, why couldn't you just EQ it out?

 

Sure they can tell you if it has a flat FR and low distortion. You mention some people like peaks and valleys and coloration though and seem to pass it off as the params and dumax can't tell us these things, but they can. They can tell us all about a bad driver as well as a good driver.

People tend to submerge themselves in the numbers and "perfect driver" debate, and use this same arguement as to why these numbers mean nothing. Yet they ignore the things that the #s can tell us about, what may be considered, the "not so perfect driver".

Just because a driver is objectively better, doesn't mean that you will like it. But if you learn to read the #s outside the "perfect driver" you will see the pattern that develops with the drivers that produce the sound you prefer . [/b][/quote]
First of all - I know that i am not well liked here, nor is bigbassman - none the less i do have something to say, and i am not flaming...read it...it may be worth reading

Until you have tested the driver, in box, in car with a amplifer producing True signal - and get the same results as you would on a Dumax machine, your points have no backup at all. (you will never do this)

Ill agree, numbers have a point to an Extent but do take into consideration that everything you have just modeled in your wonderful box program all of the sudden changes when the driver is in car. With Power on the coil, playing a tone even...still changes

I will agree that you can pretty much predict the distortion levels you may be working with...This is where you use your head as an installer, and your ears as well.

Many people on these forums need to learn to listen with their ears, and not with their eyes :bye: