Monday, December 31, 2012

Building A Subwoofer & Enclosure

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JL Audio 12W7 Subwoofer
Building a subwoofer starts with the right driver and enclosure selection. Be careful to not buy into the many myths about subwoofers that are propagated by those with limited experience or who have arrived at fixed ideas based on exposure to poor execution, or by someone who is just repeating what they read on the Internet.

One myth is that you can have it all. Hoffman’s Iron Law dictates that between a compact enclosure displacement, low frequency extension and high sensitivity you can have any two of the three. The work of every legitimate speaker engineer clearly supports Hoffman’s Iron Law.

And nothing is more misleading than a woofer manufacturer that claims their S.P.L. (sound pressure level) woofer is also an SQ (sound quality) woofer. A singular design focus results in a trade-off in some other performance parameter.

Another myth is that the largest woofer always wins. Generally, greater surface area rules. However, the enclosure has a large say in the matter. While surface area may dictate peak output, past a certain point the enclosure has more to do with the low frequency extension.

Choosing the right woofer and enclosure combination is much like choosing the prop for your boat or differential for your car. A great hole shot means less top end. And greater cruising efficiency translates to sluggish acceleration. An SPL woofer is an exercise in a singular objective, while a SQ woofer is an exercise in precision and balance. One delivers more energy over a narrower bandwidth and the other delivers less peak output but a more linear output over a wider bandwidth.

It begins with selecting the objectives that best suit you and then knowing how to best achieve those objectives.

Earmark Car Audio

Monday, December 17, 2012

Coaxials & Component Speakers- Part II

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Stevie Ray Vaughan had a unique and distinctive guitar sound that is instantly recognizable as SRV as soon as you hear it. Although he played a variety of guitars, many of them vintage Fender Stratocasters, his guitar sound was unlike the typical Fender Stratocaster sound. His main guitar, appropriately named “Number 1”, was a 1963 Fender Stratocaster body with a 1962 Strat neck and 1959 Strat pickups. No one else could pick up his Strat and make it sound like him. SRV had a MASSIVE signature sound, especially in his later years, that was full bodied and rich with tonal qualities that resembled a hollow body blues/jazz guitar with an extra deep growl. He used huge strings (.013 to .058 heavy gauge) and jumbo-style frets to facilitate intense string bending. He liked an oversize neck radius. His guitars had super high action which means the strings were stretched high above the neck and his aggressive playing style tore the calluses off his fingers, which he would superglue back onto his fingertips. He played with strength and power.  SRV used an Ibanez Tube Screamer overdrive pedal as a line driver of sorts to purposely overdrive the input stage of his tube amplifiers driving well broken-in speakers. In the studio, SRV would mic a mix of mostly Marshall and Fender amplifiers/speakers, sometimes playing through as many as 32 amplifiers at the same time in the studio. That describes some of the reasons for that warm and ballsy sound.
Well, I personally want a coaxial or component speaker that portrays that unique sound honestly as SRV intended it to be heard. In balance. In attack. In its entire bandwidth. In its lack of coloration and lack of bias. In contrast, when you hear a peaky and strident speaker with over-emphasized treble that butchers the SRV sound, you instantly know it. The initial bright appeal and appearance of false detail quickly passes as SRVs artistry is turned into a thin, tinny, transistor-radio-like guitar squeal. That is NOT the way SRV is supposed to sound.
The above example also translates to vocal balance, particularly female vocals, and every musical instrument for which we have a real world reference. I want to hear highs that represent tiny percussion instruments, such as chimes and triangles, as being small and delicate as they are. I don’t want to hear harsh, crashing and smeared highs unless that is how the original mix was intended to sound. Hey, if I want them to sound like tiny trash can lids imitating tympani cymbals being slammed together, then I can accomplish that on my own with a basic treble control. Plus, the listening fatigue associated with highly tilted and erratic sounding speakers can be brutal. As a lover of music I want to enjoy my system endlessly and avoid speaker-induced fatigue.   

I invite you to visit an Earmark store for an audition and to hear for yourself the differences that I am explaining. You’ll find the most knowledgeable people to show you the very best speakers that the mobile electronics industry has to offer.

Earmark Car Audio

Click here to read our earlier article: Coaxials & Components- Part I

Monday, December 3, 2012

Porsche Cayman Install

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2006 Porsche Cayman

This is one tricked out Cayman. Engine, suspension, roll
cage with sway bar, body kit. Also yellow highlight
rally tires, brake calipers and headlight covers.

Custom dash bezel painted Cayman
white with Alpine touch screen radio.
JL Audio 8 inch subwoofers are flushed into each quarter panel.

This panel covers and protects the two amplifiers. The crossflow cooling
fan on the right pulls air in through an opening on the right edge of the
amp cover and exhausts it to a matching opening on the left.
The plexiglass window is framed on the left and right with LED light bars.
The yellow accents on the amp cover and woofers
tie with the rally tires, brake calipers and headlights.
A six channel amp powers the door mid-bass, midrange, dash
tweeters and rear speakers. The mono block amp supplies sub
bass to the rear woofers. Multiple amplifier channels allows
perfect tuning of the speakers to the cars enviroment
through crossover and amplitude adjustments.

Lots of tight rockin bass with almost no loss of storage space.

The curve on the finished out subwoffer cabinet design
is a reverse matching slope of the rear fenders.
Carpeted viewing window cover protects the plexiglass
window while hauling cleaning supplies on trips to shows.

Monday, November 19, 2012

Great Bass In A Tight Space

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Land yachts are quickly disappearing. Cars and crossovers have been on a course where space has become much tighter. There are more factory electronics now. Every concealed nook and cranny seems to be filled with something essential. Cabins are proportionally larger and dead space is rare. But, if you want great bass reproduction you need to have a sizeable subwoofer enclosure. Cars are also being built better now, often having solid or nearly sealed rear bulkheads. This compounds the problem of getting bass radiation into the cabin of a sedan. Much of the structure is in place to attenuate road noise and increase the structural integrity of the vehicle. So you can’t remove anything. Add to that, the fact that many vehicle owners want great bass but in a stealth installation…heard but not seen.

A good car audio designer must have quite a few tools in his bag because every vehicle is a little different and one size won’t fit all. Each individual vehicle will dictate a varying approach if you want to get the best bass performance. A good car audio designer must be able to understand and effectively execute a number of subwoofer loading schemes with equal effectiveness including infinite baffle, aperiodic, air suspension, bass-reflex and bandpass to name a few. The parameters of the sub driver must match the particular method of subwoofer loading (enclosure type) and each enclosure has to be modeled independently to uniquely fit a given vehicle. This requires a little computer power and a very good subwoofer modeling software.

Sure, many can get passable results with the audio equivalent of a dead blow hammer. What they lack in precision they make up for with the leverage of more power, more subwoofer and more enclosure space. We can certainly do that. But, when the situation calls for a more creative and knowledge-intensive approach, we have many more alternate solutions that yield better sound quality. The challenge is what makes it interesting.    

Earmark Car Audio

Monday, November 5, 2012

BMW 528i Install

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BMW 528i
 Before we started on the speakers.

 Beginning stages of door panels.

Final stages of door panels.

Hertz high energy 3-way component speakers
installed and maintain factory look.

Just wrapped in vinyl.

Carpeted inserts installed and vinyl trimmed.

 Testing LEDs and location for best effect.

Factory fold down arm rest. 

A factory look with two 10W0 subs firing through.

Final test looks great and sounds even better!

First view of the trunk.

Bit ten and JL Audio amp mounted, tuned and tested.

Trunk finished and ready to deliver. We added a
raised JL Audio logo under the carpet for added effect.

Monday, October 22, 2012

What Is The Difference Between Unregulated Versus Regulated Amplifiers?

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JL Audio HD900/5 versus JL Audio XD700/5 Amplifier

Today, most amplifier power is rated at a 14.4-volt supply at 1% distortion and at 1000- hertz. None of these qualifiers are particularly relevant to how you actually use your amplifier. With a resting battery voltage of 12.7 volts, and while running your air conditioning and headlights, it is unlikely that you will have anything close to a 14.4-volt supply. You may also have a 15% power roll-off at 50 hertz, as compared to an easier to produce 1000-hertz test tone. There is virtually no headroom above the rated distortion, as most amplifiers have hit the wall at this point.

An unregulated amplifier gives you a premium of power with a 14.4-volt supply but may lose 30% of its rated power as the supply sags to 12 volts, for instance.

There are many types of regulated amplifiers, but in a strictly regulated amplifier example for this discussion the amplifier will maintain its full 14.4-volt rated output power even with an 11-volt supply. And, the amplifier will produce the same power with any stereo output load from 1.5 to 4-ohms. A strictly regulated amplifier will definitely need a more robust internal power supply. However, the intention of a strictly regulated amplifier is not just to deliver more power at lower supply voltages, although it is a nice byproduct, but the primary objective is to build an amplifier with higher stability and better sound quality.

Earmark Car Audio

Monday, October 8, 2012

Deeper Understanding

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Every once and a while an artist comes along that is truly unique. For example, Led Zeppelin drummer John Bonham had such a distinctive sound, a combination of speed and power coupled with a unique feel for the groove of the song, that you find yourself zoning in on the drums, even with the voice of Robert Plant and guitar of Jimmy Page on the same cut. 

Another such example is the genius of Paul McCartney and his incredibly melodic bass lines. Prior to The Beatles, the bass player was never a “front man” in a pop group but Paul McCartney changed that. He brought the bass guitar (and bass players) out of the background by creating a melodic counterpoint to the main melody of the song. I can just visualize the Beatles and Paul with his Hofner bass making it look so easy. But it’s not. In fact it’s amazingly complex. To learn just how musically complex these bass lines are read this article: 'The Melodic Bass Lines Of Paul McCartney By Rob Collier'.

Or, you can just hear these fantastic melodic bass lines on your audio system. Or, can you? Most cannot. You mean you thought a bass guitar was a percussion instrument that was plucked and vibrated just like a mallet striking a kick drum? Nope. It’s not supposed to be anyway. It’s a stringed instrument, just like a lead electric guitar or a violin. And you should expect to hear a degree of tonal definition and pitch accuracy like all other stringed instruments. Unfortunately, most subwoofers cannot reproduce bass with that much accuracy. Think about it. Many people describe their subwoofer as “It hits!”, “It pounds!”, or “It slams!”. Sounds like they’re describing a percussion instrument to me.

Have you seen the guy that is standing behind his vehicle as the bass pounds, and how much pride he takes in the way his license plate vibrates. It’s like a badge of honor. But I’ve never seen a band with a musician strumming on a license plate (maybe in a prison band). When the subwoofer becomes the instrument rather than the reproduction medium then you have lost touch with the music.

The fact is that most have never heard the possibilities from a really great musical subwoofer system. So if you get bored with the constant monotonous sound of the typical subwoofer and instead you want to listen to real music, it might be time to visit us!


Earmark Car Audio

Monday, September 24, 2012

Ford Fairlane Install

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Indash Custom Autosound receiver/CD controller
 looks plausibly factory and does not require any
modification to the dash.

The front kick panel speakers received custom
grills patterned after the Ford model logo.

The trunk contains subs, twin amps and a CD changer.

Boston Acoustics fan-cooled amplifiers.

Boston Acoustics 12-inch subwoofer
and 12-inch passive radiator.

A CD changer flushed into a pattern that is
symmetrical with the opposite amplifier panel.
 Custom rear seat pods conceal the rear speakers.

Thursday, September 6, 2012

Installation Matters!

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Want to build a 4-cylinder Honda or Acura into an 11-second street machine? It’s very possible, but you won’t get it done with a box of turbos, headers, intakes, fuel pumps and electronic ignitions. It takes an experienced pro to correctly install the gear (assuming that it is the ‘right’ gear) so that it works in unison and the sum of the parts reach the collective potential. More importantly, someone with real know-how and skills must tune the engine with their laptop. There aren’t many who can make a difference.

It is similar to the difference between the guy who mans the grill at a Burger King and a 5-star chef. One of them ‘gets’r done’ and the other creates a dish that is a slice of heaven.

Well, it‘s much the same with your car stereo system. At many (it may be more accurate to say ‘most’) mobile electronics companies, they consider your audio system completed when everything is verified as simply working. When all the speakers play and all functions work, it is time to clean up. You’re done. That is the Mobile Electronics industry’s version of ‘fast car stereo’. Unfortunately, at that point it is what comes next that can make the biggest difference in performance…TUNING.

 A real car audio technician must own or have access to a scope, an RTA, a multimeter and a laptop, plus a sine wave and pink noise generator. And, he has got to know how to use these tools. If not, your car audio equipment investment is just randomly connected boxes. They may all play together, but you are definitely missing the soul of the music.

Earmark Car Audio