Luin

Many on here may have seen my "noob post", but if you didnt I talked about sub bass in the rear deck of my sc300. Well I got a PM from a user talking about only having just over 6" of space to work with. Well I think I have found a solution.....

SHALLOW MOUNT SUBWOOFERS!!

I know what your thinking, "there isnt one out there that can perform the way normal subwoofers can, well I think I may have found the sub.

Ladies and Gents, introducing the Power Acoustik Silver Edition Shallow Mount subwoofer!!
http://www.poweracoustik.com/pa2006/...UDIO_SW_SD.htm


There are two versions the STW10 (10") and the STW12 (12").

Here are the specs on the 10"
STW-10
• 800 Watts power handling
• 400 Watts RMS
• 100 oz . magnet
• 2" BASV/Kapton Hybrid 18 AWG Voice Coil
• SPL 88 dB
• Fs: 35 Hz
• Vas: 0.08 cu.ft.
• Qms: 8.133 . Qes: 0.4778 . Qts: 0.458
• Xmax: 0.3"
• Less than 3" mounting depth
• Sealed box: .7 cu..Ft.
• Ported box: 1 cu..Ft.
• Tuning: 38 Hz
• Port size: 3" (dia)x 10" (length)
• # of ports: 1

Specs on the 12"
• 1000 Watts power handling
• 500 Watts RMS
• 120 oz . magnet
• 2.5" BASV/Kapton Hybrid 18 AWG Voice Coil
• SPL 89 dB
• Fs: 32.8 Hz
• Vas: 1.7 cu.ft.
• Qms: 4.49 . Qes: 0.737 . Qts: 0.683
• Xmax: 0.3"
• Less than 3" mounting depth
• Sealed box: 1 cu..Ft.
• Ported box: 1.5 cu..Ft.
• Tuning: 35 Hz
• Port size: 3" (dia)x 7.75" (length)
• # of ports: 1

Power Acoustik have been around for years and they do make beefy subs.

My roomate has a 15" **** **name of sub** in his suburban with a zapco studio 500 (900 watts) and it gets LOUD!

The 10 really impresses me, but the 12 is a all out in your face woofer! ha!

You can get either sub under $100 shipped on ebay, im sure you can get them at a authorized dealer, but expect to pay lots more.

Yes there are other shallow mount subs, but none of them have the great specs the Power Acoustik models and the "others" are more expensive.

I am going to look into purchasing a 12 very soon and im sure I can get 1.5 cu ft above the gas tank.

Robert_J

ED has similar shallow mount subs for $70 each, factory direct. There are dozens of reviews from satisfied customers on their forum. They also have a 5 year warranty. As for "great" specs, like most Asian built subs there's no independent verifications of their specs. Most of the dedicated car audio forums I visit put Power Acoustic in the same category as Audiobahn. All flash and no substance.

link

-Robert

MJHSC400

Edit-- 0.3" XMAX-- = 8mm one way--

All the while, the huge surround makes it appear to have a 15mm one way, or even more--

Look at this sub just as a reference-- MTX RFL Competition sub This sub looks to have a similar surround called "hi-roll" and yet it has 2.17" INCHES of one way xmax-- That equals air equals pressure equals pain-- I know we're not looking for pain here, but 8nm vs 50mm xmax, one is real and one is a poser....

Ok, i understand we're talking about shallow mount subs here, but you have to consider that even the Cerwin Vega stealth 10" woofer has more excursion than that, and it fits in the space provided quite easily-- While being a supremely competent and far more efficient (much cleaner and more musical) freeair sound quality subwoofer -- AND, it doesnt' appear to be anything nearly as large as that hunk o $ hit in the pic up there...

Many companies are getting the idea these days that people will buy their subs if they appear to be louder, just by doing the really large roll surrounds and making them look like they mean business-- While they are really just a marketing ploy--

Luin

Thanks for the two great posts.... It helps me out even more.

The main difference between the ED and CV sub and the Power Acoustik sub is the PA sub will take more power. I am a power nut! I love good clean power. I own all Zapco amplifiers and none of them are less then 1000 watts each.

The CV Stealth is a bad sub, dont get me wrong, but they are also non existant anymore for parts. Im not saying I will be blowin sheet up, I just like to have the warranty. So the ED sub may be the right sub for me. The price is nice also. lol

I know some people with ED, so I may have to give them a call and see if we can work out a group buy.

MJHSC400

The PA spec sheet SAYS it will take more power-- BUT, that is more than likely a load of horse **** --

I go to school expressly to avoid jobs like that, you know, shovelling horse****--

Robert_J

Power ratings on subs are one of the most usless specs since they started putting magnet weight. Most of the time you will reach the maximum linear excursion of the sub before it ever comes close to reaching the thermal (RMS rating) limits.

If you check out the Theile/Small paramters, it doesn't list Xmax. It lists peak excursion, sometimes noted as Xsus or Xmech. That is the mechanical limits of the driver. Xmax is linear excursion. Based on Wikipedia, Xmax is 11.65mm. ((Voice coil height of 39.2mm - gap height of 15.9mm) / 2)

-Robert

MJHSC400

This suggests the xmax is not the end-all measurement, and the "non-linearities" mentioned are a factor of measure that is no doubt engineered into the whole transducer package in order to achieve certain goals, though these actual measurements used by the engineers are never given it seems--

That suggests that two loudspeakers with the same theoretical xmax will very likely have very different performance once driven to their maximum mechanical limits---

I believe these mechanical limits are engineered into the design of competition subs like the RFL in order to compensate for the sub's tendency to continue moving in the driven direction (inertia) well past the theoretical linear capabilities, and this area of design will determine the subs total output in a competition setting, where total output is more important than sq--

It's just my thought that regardless of xmax measurements, the real feat here is to engineer a sub to remain linear as possible well past it's motor's operation--

I just don't think PA even touches this realm when comparing to a company like JL, with their benchmark subs of old, like the (old) w6's, with only a 12mm xmax (i think)-- not extravagant, but they played very linear and clean all the way up to their mechanical limits-- They would also smack other subs with the same xmax like a stepchild--

Something the kappa perfect does well also--

Robert_J

I agree completely that PA doesn't hold a candle to some of the big names. I know that JL makes a very high quality product but I'm just not a fan of the prices. By the time it goes through the distributor and the retail outlet, it's through the roof. And the wholesale price from the factory takes into account all of the promotion expense as well as premium product pricing.

I like Adire Audio's take on xmax measurement. They measure BL (motor strength) and when it drops to 70%, that's the xmax. Dan and Dr. David have measured a lot of different harmonic distortions as the BL drops and they decided that 70% was a good value. This also led them to develop a linear motor technology called XBL^2. The BL measurement is almost completely flat until the coil moves out of the magnetic gap. So their Koda, Brahma and Tumult series play very linear, with very low distortion right up to their max excursion. When the Tumult was first being tested, this turned out to have one drawback. You don't know when you are pushing the sub too hard until it is too late. They used a Crown K2 and just kept increasing the volume and the driver never showed the typical signs of stress (distortion) until it failed. I think they were well over twice the recommended power for the driver when it did finally bite the big one.

I also like Resonant Engineering's take on the linear BL motor. They went the opposite of Adire and use a split coil instead of a split gap. Their new XXX series has a linear BL and a true xmax of 50+ mm.

-Robert

MJHSC400

The prices do suck-- but used ones can still be bought cheap and reconed--

I think the BL is a reference to the cone mass/weight, which corresponds directly to several factors, including speed of response, but indirectly related to strength-- (cf cones are light but very rigid)

I've had a few good subs, and the perfect is one of the best--- it does more than you need it to in every way-- and they're $189 a pair shipped right now--

I'm just taking the oem sub out of the rear deck for now to see if the sound will propagate well thru the hole in the deck. If it doesn't, I'm all over the ed slim sub. I will most likely fit a very slim box behind it to maximize it's ability.

There are some dual spider designs out there that work wonders on keeping subs linear to their peak-- I haven't looked at those you mentioned, but that sounds like a good thing to research.

One day the cheap subs will be better than todays good subs. I will bet that the PA sub pictured above has a very crazy frequency response that is all over the place and lacking in places you want it to perform for a freeair sub.

The ED looks like the best way to go---

I may still get one just because they're so cheap--

Robert_J

That's the mms parameter. BL is the force exhibited between the voice coil and magnet structure. Measured in Newton meters.

Speed of response is directly related to the inductance of the voice coil. Adire Audio disproved lighter cone theory a few years ago with their Woofer Speed white paper.

I've seen a few Perfect sub reviews in both car and home environments and all were very good.

Dual spiders don't help keep the response linear. They help keep the voice coil centered over the pole piece especially during extreme excursion. When I talk about linear, I'm talking about the BL vs excursion graph on page of the XBL^2 details paper. As you can see from the 2nd graph on page 2, how much THD drops when the BL is linear.

-Robert

MJHSC400

ok--

I see what they mean by linear-- as in a linear distance vs. power-- not how aligned it is-- makes sense--

BL, okay--

I still disagree to some amount that speed IS very related to the weight of the cone-- BUT-- I mean this in conjunction with efficiency too-- as in most sq subs are more efficient with lighter motor structures and lighter stiffer cones --

ALSO-- The speed is related to damping-- which is very related to enclosure design-- A infinite baffle design has the fastest response and greatest musicality vs any other alignment-- Only a transmission line can come close to the efficiency and speed, while a TL also adds some serious response lower in the curve that an IB can't even come close to.

The damping is directly effected by the motor and cone weight/material as well as the enclosure, and damping also effects speed of response vs. amt. of power (efficiency) --

How then could it not be in any correlation with speed--

Robert_J

It's not just the weight of the cone, it's the weight of all the moving parts including the voice coil. These massive subs that have a 4" VC end up with a having a very high inductance. The inductance of the voice coil is just like the inductance of a crossover coil. The higher the millihenries, the more energy it stores. The stored energy directly affects the way the coil interacts with the motor assembly. This interaction is also frequency dependent. That's why a large sub may sound sloppy on kick drums. The "kick" is in the 60 to 80 hz range. With poor transient response, it won't have a sharp attack and decay because the voice coil is storing energy. These high inductance drivers need to be crossed over at a lower frequency.

Lets look at the TC-1000 15" model. The inductance (Ls) is 2.64mH and the mms (moving mass weight) is 238 grams. Compared to the TC-5200, the inductance is 6.56mH and the mms is 517g. It's been discussed at length that the TC-1000 series can easily play past 120hz while the 5200 series needs a cross-over around 60hz. It's not the cone weight. In fact, the titanium cone of the 5200 is lighter and stronger than the aluminum cone of the 1000. It's the MASSIVE 4" voice coile on the 5200 compared to the 2" model on the 1000. Not only is it heavier, it has a much higher inductance.

That's enough rambling. Dan Wiggins explains it much better. And it's really difficult to argue with physics.

On enclosures, the IB should sound the most musical since you are taking the effects of the enclosure out of the equation. The quality of sound is now all from the driver. In my 20+ years of speaker building, I've never built a TL so I can't comment the sound quality.

-Robert

MJHSC400

Thanks for the science aspect-- Really-

TL's will blow your mind -- basically a IB that will play all the way down to 20 hz solidly and cleanly-- unreal really, but take an enormous enclosure volume to do so--

The power involved in the whole equation was the weight of my argument, which really translates more to efficiency alone I guess-- so now it's much clearer, but I still would argue that a more efficient sub will be much more musical with a faster response-- maybe that's where I was going..

Thanks Dr. Robert

Luin

I am ordering a ED slim sub very soon.

According to their site I dont have enough depth for a ported box, so im just going to build a nice sealed back and go from there!

The max im going is.....
5.5" tall
12.75" wide
13" deep **front to back**

With those measurements that will give me .299cF

The ED 10 shallow woofer requires .3 sealed.

Also for $43 shipped ED will produce the box for me!!

Now I need to find out if there is 13" between the two rear deck speakers to mount this puppy flush with the rear deck.

Luin

update** The box will fit in that area, super close, but will fit. If its really close I will be hackin up the rear deck to make a custom rear deck with my enclosure. Heck now im almost thinking of doing 2 of the 10s!