cvjoint

So far I've shown version one of the build, but also version 2 and 3 for the subs only. I'm going to update the thread with:

Version 2 midrange drivers

Switching from BG Neo8 planar (1600hz-5khz) to dual pro audio 4.5" cone speakers in an MMT (midrange midrange tweeter) design (200hz-6.3khz):

Pods modified to fit duals:



MMT:



The paper cone treatment gives them quite a bit of shine for a paper cone. I was coming down from the top of the parking structure and I kept staring at how gorgeous they are as the parking structure lights illuminate the cones.

Phone camera doesn't do it justice but:




FR Faital MMT vs. Neo 8 as I did for the rest, vol 36 on the head. They are getting 90w @ 4 ohm in parallel just like the Neo 8:



Total ownage over the planar. Anywhere from 3db to 17db more output up to 12khz.



As for comb filtering, when I had one single driver mounted I took a pic of the FR at higher resolution just to see if comb filtering could exist at 1/24 octave smoothing but not at 1/6 octave like I usually test. The ear is generally believed to hear sounds as if 1/3 octave smoothed. Unsmoothed looked too nasty to even overlap imo. My basic interpretation of this plot is that the additional output seems to die down a bit as frequency increases (and comb filtering becomes more of a problem). Initially I didn't see this pattern. Also on this topic, the mic SPL level was right at 6db more with dual mids than the single, just as predicted. That seems to indicate that there isn't any comb filtering and therefore output lost to it. But then I thought about how dual mids sharing the airspace of one could increase system Q too much, cause ringing, and therefore boost the low end response. That part is clear, look at 200hz-500hz, lots of low end peaking here, the QTC was around 1. Adding a second driver and feeding it equal power should never boost output by more than 6db. You can see about 9db boost in this region. This was one of the drawbacks of the dual mid setup and why later on I replaced it with version 3 midrange.





NOTE: this was before I knew how to mute channels on the P99, even at -25db the other speakers provide additional output, but maybe not enough to make a big difference

THD @95db:


THD @100db:


THD @105db:


THD @110db:


Heck, more! That's a single pillar pod crossed down to 200hz!

THD @115db:



95db Excelent!
100db Excelent! Most of it under .3%!
105db Excelent! All under 1%.
110db Some problem areas begin to appear, 2% distortion at 200hz and 630hz. At 200hz the distortion is probably motor induced from the need for higher excursion. The 630hz is probably my car acoustics. Note that the 3000hz problem area we saw before is there but still under 1%. The rest is under 1% as well.
115db Under 3%, amazing. It was so loud it started being annoying even with ear plugs on.


Even at 100db in a car these guys had on average .3% distortion. There is nothing that tells me these are compromised drivers for esque. Those voice coil leads coming through the cone are not pretty but perhaps it's a bullet proof way of insuring against tinsel slap. It's pure badass. In fact I'm surprised the protection ring they have going around the surround doesn't mess up the frequency response too much.

aphex4000

Such an interesting build, only wish I could hear it in person!

cvjoint

Every month it is different!

cvjoint

Midrange + Tweeter options over the years

Overview:
Version 1: BG Neo8 planar (1600hz-5khz) + Vifa NE 3/4" dome (5khz-20khz)

Version 2: Dual pro audio 4.5" cone speakers Faital in an MMT (midrange midrange tweeter) design (200hz-6.3khz) + Vifa NE 3/4" dome (6khz-20khz)

Version 3: NewDual pro audio 4.5" cone speakers Faital in an MTM (midrange tweeter midrange) design (200hz-3.1khz) + Scan Speak Illuminator 3/4" dome (3.1khz-20khz)

Version 4: New: BG Neo10 planar (200hz-3.1khz) + Scan Speak Illuminator 3/4" dome (3.1khz-20khz)

Version 5: New: BG Neo10 planar (200hz-3.1khz) + Aibone 5002 air motion transformer (3.1khz-20khz)

Version 6: New: BG Neo10 planar KICK (200hz-3.1khz) + Aibone 5002 air motion transformer (3.1khz-20khz)

aphex4000

Wow, this is a like an audiophile's wet dream!

Which A pillar setup did you like the most?

cvjoint

Hard to pick between 5 and 6, basically the same driver but one has the mid in the kick vs. pillar.

I'd say when the mid is in the pillar Pros are:
distortion is lower, output is higher, intelligibility is higher, focus is better
Cons:
it sounds very NPR-like, close and small

The kick panel Pros are:
It sound large, deep and vast
Cons are basically what the pillars have going for them:
higher distortion, lower output, inteligibility is lower, voices can't be placed very well.


In version 7 I will double up both drivers in pillar and kick, this way distortion and output performance are great even in kicks. I prefer the larger deeper sounding car despite not beeing as crisp as all in pillars. This way I get a slimmer pillar too. Version 5 is ridiculously large!!

cvjoint

Subwoofers take 4: Peerless XXLS 12" - THE benchmark for quality sound reproduction



These are the latest model, using an anodized aluminum cone:
http://www.madisoundspeakerstore.com...um-cone-4-ohm/

They are IB as all the other ones, in my 5 cube trunk powered by the 1200w ARC KS monoblock.

Subjective impressions:

I have once again proved to myself that the LAT700s are a beauty of a driver. Right away, the Peerless drivers brought back the honk, dullness, and the long forgotten rattles and vibration. It makes little difference what conventional drivers I use, they all have the common drawbacks: AE IB12, Vifa NE 12", and now Peerless XXLS 12". The reason why these conventional drivers hit "hard" it's because they litterally hit the chassis, not in a good way. The seat resonates, the rearview mirror rattles on the windshield. At low volumes it sounds honky and generic. A lot of the detail in bass lines is smoothed out with noise. Every bass note excites the car, and now that I have experienced mechanical Push-pull with the Tympany LATs, this is simply... unacceptable.

I will be going back to LATs soon!!

Pros:

It does get louder, downright brutal. There is no sign of strain no matter how much I push them but the car itself cringes. To get the additional output over the LATs you really have to accept an unsurmountable amount of rattles and vibration. So for 0.000001% of the time the extra output can make you happy, but the loss of quality...oh my.

For those that want some feedback on the 12s, in order of best to last:
Vifa NE 12"
Peerless XXLS 12"
AE IB 12"

The NE dug the deepest, was the most efficient, can be crossed the highest, was the lightest, used the most advanced materials, etc etc... The XXLS may keep it's composure a little better at high SPL but low to mid the Vifa was a better driver imo. The AE IB12s suspension makes the Tympany drivers a better choice for sub use. As a midbass I'd reconsider the AE but a good suspension is more important than the improvement in inductance management (the Danish drivers still have very good farraday shielding).


History background:
The Peerless XXLS was one of the first high excursion high quality subwoofers to hit the market in the 90s. Many of the top notch sound quality speakers we have today benchmarked the XXLS in being created: Dayton Reference, TC Sounds tc2+, Adire Shiva etc.

In the late 2000s Vifa merged with Peerless and a new driver, the NE 12" was created. It is a better driver imo.

In the mid 2000s Tympany - the father company, created the LAT technology, and many research papers have been written to explain the monumental effort. It is imo, an unmatched technology and I've proven it over an over to myself by comparing it with the rest of the 12"s in my car.

AE IB12 is also a rival of the Peerless XXLS that has roots in a Lambda and TC hybrid motor.

deception9

CV just wanted to say excellent build thread, pretty easy to get the gist and lots of info (although all the graphs are over my head!). while all of this is out of my budget the infinite baffle set up really attracts me.

right now i'm running a alpine type s 10 in my own box made to fit in the spare tool area. the volume i'm not precisely sure of. i am using a alpine mr500 amp to power it (500w at 4ohms or something around there). i'm not happy with the bass response.

my question is, is it really necessary to fiberglass (or some other material) in a large baffle? would the same effect be achieved if i just cut my panel out of MDF and installed the subs over the carpet OEM panels? or does this get rid of the benefits?

also you said that the area you "use as a box" was barely enough volume/cubic space for your first 3 twelves. would running 3 tens be more appropriate? what about 2 twelves and a ten?

cvjoint

Best thing to do is imagine the perfect infinite baffle setup and compare to what we can achieve in the S2000. The perfect infinite baffle is mounting the sub on to a wall that is infinite in every direction. That way the baffle, here the wall, is very stiff and no output is lost since the wall has nearly 0 recoil. The other benefit is that the front and rear waves never meet, can't go through the wall. Therefore there is no cancellation.

People will tell you subwoofer boxes are great because they provide "spring" action so that the subwoofer is not bottoming out and you can "feed" it more power. This is false. The box is a necessity so that the front and back waves don't cancel eachother. In return the "spring" action is reducing efficiency. That means more power is needed to move the cone. That is bad! More power for the same output means the coil has to suffer a higher load, heats up more, in turn losing a lot of power to heat and possibly overheating and burning.

So let's recap. We would like to separate the front and rear wave but get the least amount of "spring" action to improve efficiency and therefore sound quality as well.

In an S2000 the environment is the interior space of the car trunk+cabin. The ideal split is 1/2, the speaker baffle right in the middle such that the smallest "box" is as large as possible. The way I have mine oriented it's 5 cubic feet in the trunk, and probably a bit more in the cabin, so the trunk is the strongest "spring".

The wall that you mount the speaker to has to be stiff (no recoil) and completely deflective (front and rear waves don't meet). I chose fiberglass because it is stiff (little recoil), seals well (little cancelation), and weighs very little.

So what you propose: a wood baffle just fastened would only satisfy the first criteria - it will be stiff (little output lost to recoil). But the front and back waves would communicate through the gaps. The larger the gap, the more cancellation. Carpet won't help much at all for bass frequencies.

cvjoint

As for box size, the bigger the better, ideally infinite, aka infinite baffle. I have 5 cubes, and can't really get any more. The first frequencies that suffer from a small box are the lowest ones. So if I don't have enough output at 20hz I use the EQ. to raise the output there. So you can use the equalizer to make up for having a small box. But be careful! EQ. is not free, 3db boost on the EQ. means twice the power is required, so it is very likely to clip the amplifier when the song has a 20hz note of high amplitude. So now if we use a small box, we can band aid with EQ., but we also need a larger amplifier. Once we have EQ. and more wattage the coil will still have to dissipate twice the power. That means power will be lost to heat more, so maybe we need 4db boost + an even larger amplifier such that the total output of the speaker is up 3db.

All this means biggest box is best, stiffest baffle is best, and that band aids exist (like EQ and biggers amps) but the costs are high. I wish I had more than 5 cubes but most S2000 sub boxes are way smaller.

Next why do I use 3 twelves and not 3 tens? The more surface area you have 12" vs. 10" the lower the excursion needs to be to produce some given SPL. With 12" I can keep excursion lower, which lower distortion AT ANY OUTPUT. The farther the cone travels, the higher the distortion. Then let's not forget that 10"s don't have infinite excursion, so in effect 12" are bigger pistons and often have higher stroke as well: will produce more output as well as produce less distortion.