Monday, November 30, 2015

"POWER", The Myths and Maths Series Part 3 - Amplifiers

Amplifiers.  Love them or leave them, they're one of the most abused and misrepresented links in the audio chain.

First some myths.  "Digital amplifiers are the best!".  There are digital amplifiers but they're not used in HiFi.  Digital amplifiers are used in telecommunications equipment to boost a digital signal on an analog format like coaxial cable to your home.  Even that isn't really a 'digital' amplifier, just an analog amplifier boosting a digital signal. (These also may be Class AB, Class D or even Tripath amplifiers)

The "D" in Class D does not stand for digital

Class D also known as a switching amp, is simply a variation of an amplifier in a long line of variations.  For example, Class A, Class B, Class C, Class D.  To keep track of different topologies, the EE community came up with a letter system.  If you invent a new way to amplify, you'll may just be granted the next letter which could be Q or W which I know doesn't sound as cool as D but it'd be a great addition to the community.  This letter system is helpful as some variations use combinations of topologies / formats.  Like Class AB which is by far the most popular.  Another example is Rockford's use of the combination of Class B and Class D amplifier topology, (BD).  My favorite is Class GH which has the sound quality of Class AB but the efficiency and low impedance features like Class D.  Class GH however is a proprietary technology and must be licensed if put into production.  Several brands have brought Class GH amps to market including Diamond Audio, Cerwin Vega Mobile and most recently new to the US, Vibe Audio.

Used and Abused

Amplifiers are the most mysterious item to most consumers.  The dials and controls mean nothing.  What the hell is impedance?  Why can't I bridge a mono amp?

The fact is that most of the people buying amplifiers do not know how to install them let alone how to set them.  Some manufacturers took extra steps to head this bad horse off at the pass.  In my work with Arthur Wilkes, he was in charge of testing at MTX.  His method was very practical and realistic.

At MTX, they used to test new equipment or factory samples by turning all the knobs to the right and letting it play full blast in a 'boom room', hooked up to real woofers, not resistors and seeing how long it lasts.  If it lasts a full day then it made it into production. (That's simplified of course).

Unfortunately, Mitek and it's brands in general are changing and it hasn't been for the benefit of it's customers.  It's now cheaper and easier just to replace a recently made amplifier than to fix it. This is now common for most all brands. There are of course exceptions, namely old school equipment that holds more value due to emotions than performance.

Today, nobody makes a bad amplifier.

Build houses cannot afford to make a dud, so they simply buy, "the best", and copy it.  That copy makes it's way to all the build houses.  There are exceptions of course and this is when the build house has good engineers on staff or on contract.  There are also still many brands here in the US that make tweaks to poorly executed products instead of new designs.  The problem with dealing with a build house that doesn't have integrity, know-how or just lost in translation. You can still have a great design but if it's stuffed with the wrong parts or substitutions have been made, it can lead to problems.

These build houses then figure a fail rate and compensate the buyer with more units for, 'free'.  So if an amplifier has a 50% fail rate and you order 1000 pcs.  The build house will send you around 1500 to 1650 pcs for the same price.  That seems to be the current solution to keep customers happy and and that means CHEAP boom.

Branded Cattle

Brands like Sundown have been using a higher quality / integrity build house like Chung Lam or Zenon in Korea as a means to compete in the ocean that is car audio.

(Chung Lam is most famous for being the build house for Orion and PPI in the late 90's and early 2000's before the brands were sold to DEI. DEI continued to use them until other, cheaper build houses were ramped up. If your Orion or PPI product says Designed or Engineered in USA, this was made by Chung Lam and assembled and tested here in Tempe, AZ)

Most larger companies that are serious and get good quality in China use a company called Boss.
It's not this Boss, but if you can pay, you'll get perfection.  The trick is will your customers agree with your $100k decision?

Several brands have followed in the same direction as Jacob.  Jake wasn't the first to use Zenon but he now has their ear and Sundown leads the changes in the cottage brand industry.  Sundown has created many of it's own, "me too", brands with many making exact copies with exception to branding.  Some include DC Sound Labs and Skar Audio leading the way.  Others come from another lineage created by Mark and Scott of RE Audio aka Resonant Engineering.  With Scott selling his share in RE to then go on and start Fi Car Audio and now building for brands that want to tout, Made in America, like Ascendant Audio and SSA.  This is the reason why most brands look and function the same, they ARE the same.

Some brands use a combination of off the shelf and new engineering like Nick Lemons at Stereo Integrity and Obsidian Audio.  Running Obsidian allowed him to use those funds to engineer the ultimate in thin subwoofers the SI BMIV.  Obsidian basically made a fancier version of the Sundown SA series. (Nick and Jacob also ran out of the same facility and shared in shipments.  Making subs and money with friends is the ultimate.)

For me it boils down to value or Dollar per DB.  We offer many styles and formats and many have a full 1yr warranty against anything.  Even if you screw it up during the install.

If you buy new, you may want to look at new / upstart brands like Twisted Sounds for amps or DS18. Both use mainstream construction channels from Asia but are new to market so they compete on price and quality.  They are still, "me too", brands but are a better value for now.

Later like we saw from the Audiobahn group, they may start dulling down products by leveraging your emotions about the brand. Brands like Rockford do this about every 3 years.  Last year's P3 is now this year's T1.  Some go the other way as well to make it look like they're improving.  Either way it's always shifting and changing and it's tough to lock down solid information.  I feel like this every time I buy paper towels.  There's a sale but that one's a better value all the time and I really like Select-a-size.... etc.  Sometimes it's just chrome and led's to get that emotion about a brand or a paint scheme like the old PPI Art series amps.

DS18 has already started doing this by making knock-offs of Sundown and other brands.  Twisted Sounds products will remain strong and should start to enter the woofer arena.  Travis is helping the cause by also diversifying into other aspects of the goal of loud bass like using lithium batteries rather than lead-acid.

New Sprouts of Innovation - Good Seeds and Bad Seeds

New technologies are being developed every day.  In the audio industry, this race is quite fierce.  Some brands have learned that to survive and prosper, you can't use, "off the shelf", or "open tooling", products forever.

As mentioned, many of you know about Travis Young of TS and his work to produce LiOn batteries for audio use.  Look for him to start producing solar products for DIY'ers that need energy storage. Some companies will actually land a high volume contract to pay for expensive tooling on the other end of their brand or another brand under their umbrella.  We saw Rockford Corp do this when they acquired Lightning Audio.  Larry and Scott sold Lightning to Rockford for a nice chunk.  Scott then got to retire with is new bride and Larry when and bought Cerwin Vega Mobile and Diamond Audio.  Larry helped form a brand called Fierce that you may have seen in Best Buy.

Kicker can now be found at WalMart.  Don't get mad, this is wonderful.  Kicker will displace other brands that are moving away from car audio like we saw Boston Acoustics do.  Look for Sony to be leaving as well.  Kicker will now fold that $50k to $1M a month back into the brand to tool up some really cool gear.  Someone has to pay for pimped out speedboats and coked whores, (your mom).

Not all money is well spent.  DC Audio shelled out tooling dollars for new frames like their new 8" sub the M38.  However it's still a copy of Sundown products as for performance.  So what are you buying?

For me it's always been about performance.  Choosing an amplifier for me now is about price / value.  If you can give up the need to show off your system and have confidence in your know-how and execution, you can have a fantastic system for less and that's what we've been doing at Robot Underground for over 20 years.

I love showing off a system that uses Pyramid brand components after people hear it.  One of my mentors, Mike Q. told me to, "bench it before you bitch at it".

Be aware of when a brand touts a patent.  Many times the patent will be an ornamental type, meaning it has to do with the product look, not function.  Other times like in the case of JL audio and their, (at the time), new, fancy tiny class D amplifiers.  It was another company's patent.

For the most part, make sure if you can, that the amp has a warranty.  Make sure you know what the warranty covers.  Most DO NOT cover abuse / misuse, so educate yourself on how and what to do.  Make sure you understand the shipping policies.  The norm is for YOU to pay return shipping to the seller.  Then the seller determines whether or not it's abuse or defect.  The SELLER then has the CHOICE on whether to fix, replace or just no honor the warranty.  If it is covered, SELLER pays return shipping.  Even if it's not covered, a good seller will still pay return shipping.  For us though, we buy dead subs so we often will give a 'core credit' for a dead sub towards a new one.  We also have a Forever Upgrade policy.  So if your item is covered under warranty, we'll give you full credit for it towards an upgrade to something that's more to your liking or application.

"Scotty!  We need more power!"

One of the most debated myths about amplifiers is that you can blow your sub by not having enough power.  This is misleading.  Subs don't catch on fire by sending small signals to them.  The idea behind the myth is that if you are pushing your amp too hard, (clipping), you send a distorted and usually a signal that's double the power to the speaker.

The sine wave is your friend.  If your amp has too much input, or the output is too close to a short, the amplifier will distort or 'clip'.

If you have say, a VR3 200wrms amplifier that you can find for very cheap and you turn it up too loud, aka - clip the input of the amplifier.  That perfect sine wave you're after turns into a square wave.  Square waves aren't usually the best sounding so USE COMMON SENSE and if you hear distortion or you find that if you turn it up past 20 and it doesn't get any louder, TURN IT DOWN!

20 in this case, is the maximum loudness you'll be getting.  A fully clipped square wave contains more energy than a sine wave.  This higher energy level along with being square pushes the coil out of the gap suddenly.  The more time that the coil spends out of the gap, the hotter it gets.  It's basically a portable toaster oven.  This also occurs when you push the subwoofer to the ends of it's excursion.

Some subwoofers have limiters build into them to prevent this. (Both JBL and Boston Acoustics at one time used a shorted coil of wire, above the voice coil, on the former to keep the coil assembly from traveling too far.)  Most do not so it's up to you to use common sense.  If you want your subs to go to 11, you'll need at least a bigger, more powerful amp and speakers that can handle that power.

Running a clipped signal to the amplifier also causes the amp to draw more power than normal.  This can cause anything from killing batteries and alternators to melting wire.  Remember that your system is only as strong as it's weakest link.  I would recommend a shop or brand but most all of them always have an agenda at the end of their explanation and that's a terrible abuse of the trust you just built with that client.

Lies, Lies, Lies

I wrote about power ratings on subwoofers in the last issue and they don't get any better with amplifiers.  Most all, including mainstream brands like Alpine and Pioneer post a completely imaginary power rating on their products.  I saw an Alpine Type R subwoofer rated for 3000 watts!? Even the 1000wrms rating is a lie.  The question is, "How much of a lie?"

For years bass heads have shunned brands that over rate their amplifiers.  Some common culprits include any brand from the Pyramid Group, (Pyramid, Legacy, Pyle, Lanzar).  Others include those from the Boss Group, (Boss, SSL / Sound Storm Labs, Planet Audio).  Also included are 'higher' end brand groups like Epsilon Group, (Precision Power, Power Acoustik, SPL, Soundstream, Farenheit and now shelved, Kole Audio brand).  Don't forget the crazy German at American Hifi, (Nitro, Rockwood, Volfenhag and their flagship brand, Performance Teknique.

All of these brands then have 2-5 lines of amps, PER BRAND!  That's a lot of skews and amps to sort through.  These brands, or any brand that posts a peak rating is taking advantage of the end user's ignorance.  I've had more than a few clients pick an inferior product because of the peak rating even after I did my best to present a clearer picture.  The good part for you, is that NONE OF THESE AMPS ARE BAD!!!!  None of these brands even do engineering work.

They're all designer brands.. That makes them sound fancy now.  But that's what a designer brand is, they take something off the shelf.  Meaning they use parts or a whole product that's already made by the factory.  Then they bling it up or package it in a way that makes it seem more in line with their target market.  This is where the market is now to stay in line with customer expectations of affordable boom that looks cool and performs well.

None of these brands are "bad", or "cheap", or poorly constructed.  They're made in the same factories that many of your favorite, "name brands", are made.  Many times they are even the same amplifier with small changes to color or screen printing.

I would show you what used to be a great site called Ampguts (can't even show archived pages), but Anthony, "Ant", Collova bought the site as part of the ROE forum, (Realm of Excursion), and now asks for a FEE to look and compare the boards of amplifiers that users submitted.  This may be unfortunate for now, but that's why I started which will ALWAYS be free and open for discussion by everyone.

Some examples were a local retailer called, RAS or Rabadi & Sons bought the Majestic brand and created Niche Audio.  Both use THE SAME class D amps used in several Treo Engineering amplifiers.  Funny that a brand with the word, "Engineering" in it would use off the shelf amplifiers.  Also, please update your website at least every 10 years and put some pics next to each series.  I know, I shouldn't criticize a big brand like Treo.  I guess I'm not awesome enough to own expensive stuff like that so I can show everybody I'm cool and successful.

"I want to hear solutions, not problems!"

To sum it up, here are some tips to help you navigate the growing field of electronics.  A quick way to tell how powerful and amp is:

1. Look at the fuse rating and add a zero. (Amperes x Voltage = Power in watts)

Using a conservative version of Ohm's Law we're simply multiplying the maximum current rating in amperes by voltage to get power in watts.(We're using 10 volts in this case which makes the math easy and provides a more, real world, power rating for the amp.  The amp has losses and inefficiencies that are impossible to measure without a test bench.  Remember this is a primafacie example for shopping for amps.

This is a quick way to find out the real rating on an amp.  We love the Boss / SSL tiny class D amp.  It's very compact, has great controls and features like a volume knob and high level input.  It's NOT however 3000w.  The fuse rating is accurate at 40A.  If you add a zero to 40, you get 400 which it does a solid 400wrms and is 1 ohm stable.

Exceptions: We have found Lanzar making an amp with dual 30A fuses but they're wired in series which makes it a 300wrms amplifier or better.

Also some makers just say, "Flux it!" and put an oversized fuse on it like the BAMF 5500D from Power Acoustik. (You can tell just by looking at the power supply transformers that there's no way each one does 1000wrms.  It used to have 3 450 transformers but they changed the design to two 650w transformers.)

Which leads to the question I usually get after that, "How can I get a better idea of what an amp can do without testing it?"


Audio Guts dot ORG is a free forum I'm setting up to allow ALL audio item information to be shared with others in the community.

One thing I've been doing is a simple inventory on the 3 dozen or so amps that pass through here each month.
    A. I take a few quick pics of the amp and it's board. (All sides if possible)
    B. I write down the fuse rating
    C. I write down the number and values of the capacitors the input section of the power supply.
    D. I write down the number and values of the caps in the output section of  the power supply.
    E. I write down the number and model of the devices in the power supply
    F. I write down the number and model of the devices in the output section

Using these numbers you can get a better idea of what the amp can do and what the engineer was thinking when they created this amp.

For example:
The MTX MTA225 is a great old school amp.  Made by PPI and uses 6x 2N6488 & 6x 2N6491 in the output.  With 8x 5N05E in the power supply.

You can look up the spec sheet on the output devices and you'll see that the total dissipation per device is 75 watts.  So 75 watts x 12 = 900w.  But the amp is only as powerful as it's weakest link.  The power supply devices are... Well, I don't know because I wrote down the wrong part number.  It's most likely in the RFP50N06 family which is 50A version of the device.  Very old, late 80's and used on several PPI and Orion designs.  Which makes sense because each device is good for 131 watts.  That would make the power supply capable of 1048 watts. (Remember too, that some devices are rated MORE than their package can handle.  This package type is called TO-220 and is only good for around 70W.  That's why some makers move to larger package types for the same device like the TO-247 or TO-3  Overall due to losses the amp should do around 650 to 800wrms right?  Nope.  Most amps when engineered, usually aim to use only half the rated power of each device.  So this ends up making it a solid 400wrms amp.  The idea though is that you can now compare to other brands to see what you're getting.

There are of course exceptions like the drag race here on
There seems to have been a blow out on the MTX amp.

Remember that on older amps, the caps dry out and aren't able to store the full electric charge.  That's why older amps should be serviced and gone through / inspected by someone familiar with electronics repair.  Update the caps and if it's got dead devices, ALL devices should be changed on that section of the amp so that they match.  Newer devices are much more powerful and have a lower resistance.  If you change out just one device, that device will carry more current and blow.  So in a small amp like the 225, a good tech will change out all the devices and update it.  The weak link in the chain will then fall to the caps and transformer which can of course be upgraded as well but then you basically have a much bigger amp in the same size heat sink and then that can lead to problems as well.

MTX actually toted this amp as being .5 ohm stable, (for a limited time, like for competition).   Though I'm sure people abused it and ran it .5 ohm per channel or even lower and claimed it as a superior amp because it didn't go up in smoke right away.  PPI was at the same time building a version as the ProMOS25 and of course at 2x the price because it was far superior and many fans believe it to be true.

AudioGuts will also cover ALL aspects of products including how to repair, work arounds, schematics, hacks, possible conversions and even down to the screw size thread and where to find the best price on them whether it's a personal or commercial source.

That's a wrap!

The take away from this article is that there is more, much more there than what the sales person is telling you.... and that's ok.

One reason I started Robot Underground was because I wanted to learn and was tired of being lied to.
Sales people do not get paid to teach.  They get paid to sell.  Be aware of that when you go into a retail store.  I used to hold this against them but it's not their fault.  Retail stores paint themselves into a corner by having a 'good', visible location.  This is more expensive than a warehouse or as many of you remember me working from home.  They also have a staff and they want to be paid for just being there, even if they're not doing anything and that costs money.  Insurance and utilities are even more expensive too because they know you're there to make money and will charge you more.

In the end, most shops follow the same patterns of bad behaviors.  Up-selling when it's not needed.  Charging too much for an item to begin with.  Charging you for 12ga OFC when they really gave you 18ga aluminum wire.  Charging you for a custom box when they buy it pre-made for super cheap.  In the end, just lying to you and taking advantage because you don't know any different.

If you did know different, you wouldn't be there in the first place so it's kind of your fault too.  No need to blame.  Just chalk it up to a learning experience and do something different. Just don't be the person that goes $50k in the hole for an education, just to end up working at Starbucks.

This day and age is much better than it was yesterday.  I learned what I know from car audio magazines and literature.  In fact, once I figured out how to use that information, I became one of the better students in my military training.  Without that information I would have ended up in a grunt job.

Computers and the interwebs allow you to learn at your own pace.  You can check and recheck multiple sources to make sure the information you're getting is true.

Finally, take responsibility for your education and test these lessons in your own space and time.  Experience is what really makes you a pro at something and that's why we teach the way we do.

See you next time.  We'll tackle energy sources as well as batteries vs caps with a revisit to wire.  After that we'll address audio addiction and hoarding.

Patrick Chandler
Co-Founder of The Robot Underground.

Thursday, June 6, 2013

"POWER", The Myths and Maths Series Part 2


There's been some unsolicited promotion lately by, 'independent', reviewers about the benefits of OFC over CCA wire.  The fact is that both are fine, it comes down to the capability of the wire and the application, (How you're going to use the wire).

This applies both to it's use as speaker wire and power wire... And to throw a wrench into the machine, manufacturers are developing a new type of wire that has the heft of OFC but the capacity of CCA and costs half that of CCA.  Last time I heard, it was the addition of tin, so now your wire will rust instead of just turning green.

First off, let me debunk the 'testing' that's been going on in some of these videos.  Several videos have the wire in coil, which makes for a big inductor.. Never a good idea to test wire this way. This is also not how wire is used when in the car or boat.

First, I would use a standard length that's in a kit, say 16'.  Second, identify both the wire's material and it's diameter.  After that you can actually use a chart to determine what can be used before it affects both performance and your ability to inhale large amounts of toxic smoke.

Don't worry about what is, 'spec', or what GA vs AWG mean.  Look at the material, diameter and length.  (By the way, in the wire industry there are three standards, China wire, Taiwan wire and American wire gauge. That addresses why one brand will say, 4ga and another will say 4ga but the actual wire diameter will be different.  It has nothing to do with 'quality'.  It has to do with different standards.)

Second you have to look at how the wire is applied.  Most standardized tests done are for an 'open air' test, meaning the wire is suspended in the air so that it can be cooled by methods of convection.  Then on top of that, you have to calculate what the ambient air temperature affects it.  Even more calculation if the air is moving, how fast it's moving, is it recirculating or is is coming in from a fresh source.. Just like when you want to cool your amp with a fan.

But enough of all that, most of the applications used in car or boat audio are fine with CCA.  All wire just has an ampacity.  A capability to transfer current.  For mobile audio, this is not constant power.  It's pulsed which makes a big difference.  On top of that, you'll see on many charts what the resistance of a certain gauge wire is at 1000'!  That's a big difference than the 16' to 25' that you're using.  These charts are up over 100A you can see no difference.  Take into account that speaker wire is nowhere near that type of power and is it really that important to have 10 AWG OFC?  No.

The big push of OFC is in the profit margin vs CCA.  The total volume and especially the margins of mobile audio have eroded significantly in the past 20 years.  It's no wonder brands would pay to stage an 'independent test'.  There's a good chunk of cash on the line, even after all the erosion.

In the world of audio, they can even get away with paying people with just product for good reviews instead of the usual chubby envelope given to more 'reputable' sources like magazines.  Do you really think people buy $10,000 cables?

Ok, ok... An example of power application.  Let's take the standard Taiwan spec 8ga CCA used by Metra in their Raptor line, (Just changed to 'full spec' this year).  Not getting hot enough to melt the fuse, you can still use this with a crappy, standard AGU glass 60A fuse.  This is plenty for most systems.  It may even be cheaper and have a lower profile to use multiple strands of 8ga CCA.  Of course each strand is good for up to 60A.

For 4ga CCA from Raptor, we go up to 100A AGU fuse.  Anything beyond that would require 2 or 0ga CCA or multiple runs.  Also, I recommend to many clients that get the OFC bug, to just add another run of wire rather than pull out the 'bad' CCA and go all copper.  The industry is again employing the snob tactic that you want to be superior over others.  This of course only costs you more money, that those, "poor", or "crappy", type of people won't pay.  I never agree with these tactics as they create small wars of "us vs them".  Apple is famous for using this marketing strategy.  In the end however, everyone of the unwashed masses remembers the way snobby people act and they always get taken down a notch or just taken out by an angry, poor mob.

As for OFC, if you can get a good price on it, use it.  It's not any better than CCA, it just has a greater ampacity than CCA when compared with all other things being equal.  Most of the time people never even get close to the ampacity of what the wire can do.  Now if you're competing and want to do hair tricks, that's a completely different story.  Just because they use it on a $150k demo car, does not mean that you need it for your the single 10" sub you have in your '87 Crown Vic that your grandma left you.  Use common sense, use Craigslist and always get more information than you need.

Remember that when you buy retail, from a store, you're paying for that store.  Nothing good or bad about that.  Just remember that you're paying for the store plus product, plus mark-up.

I'll take on some amp myths next in Part 3.

Patrick Chandler
Co-Founder of Robot Underground 

Friday, April 5, 2013

"POWER", The Myths and Maths Series Part 1

Let's Talk About Power! (Part 1)

    I get asked a bunch of power related questions all the time.  My goal in this series is to educate and demystify what manufacturer's power ratings mean and how to apply them in real world situations.  I will also be doing an FAQ section with references and notes when available.  You may not like the answers but when applied, these answers may be the best thing you can do.

    Let us start with part of the chain that users see most. Woofers.  Woofers come in all shapes and sizes and in all cases, the power handling numbers printed on them by the manufacturer are WRONG.  The intent of this number is another story.  Some makers are conservative, some are just liars.  Either way, any number they give you is wrong.

    The reason they're wrong is that are so many more factors in the power rating of a driver that need to be considered.  In the case of woofers, there is program, (signal, music, sine waves, etc.).  Another factor to consider is enclosure size and that relates to the overall question, "What's your application?".  How are you going to use this tool, this device that turns electricity into sound.  I myself have used a wrench to pound in a nail so keep an open mind when it comes to application.  Everyone wants to do different things and it's important to keep that in mind when helping someone or planning your own projects.  Not everyone has the same kind of budget nor standards.  Let's keep it fun and interesting though and explore several avenues of application.

    Entry Level / Woofers

    Entry level subs are by far the best money makers for audio brands / manufacturers.  They cost close to nothing to build and ship, yet the margin on these items is the greatest, (percentage), and the price point is the broadest and most accessible in the market.  In recent years, you may have noticed a flood of these products.  JL Audio for example out did themselves.  The typical 4 tier marketing strategy was W1, W3, W6 and W7 to top it off.  Now they have two more levels of performance below what used to be the entry level woofer, the W1!  That's dookie-load of sku's!  The great part about this is that now everyone can afford to buy a genuine JL Audio woofer.  What's even better is that the WX series is no slouch.  It's certainly not a W7 by any stretch of the imagination but they do get down and work great in small / medium sealed boxes which also save the end user money.  Enclosures can be almost made of cardboard and still sound great due to the low pressure.  Less packing material is required to ship and amp costs / requirements are cut down considerably.  All in all a great deal... Unless you want to do hair tricks....

    Now, back to the problem of POWER.  Assuming what I've seen, tested and heard is true, these two woofers both come from the same factory overseas and are, in essence the same woofer.  Assuming all of that, HiFonics claims this sub is good for 800w Maxx.  (Yes that's double X's because it's that bad-ass!)  JL is much more conservative in their power rating and even make a recommendation.  Their site also has a much cooler graph to show you where the , "DumDum Line", has been drawn at no more than 200w.  With that said, neither of these ratings do anything to address application.  Both of them are wrong and yet, 'acceptable' and legal answers to what these subs can take. (Also don't worry about the secret of the HF series subs getting out.  People that buy the HF series are not the kind of customers JL wants.  (More on that later in the buying / selling blog entry.)

OUCH!  That's HOT!

    So what's a girl to do?  Michael Q. aka Q-Daddy, one of my early mentors broke it down this way.  Imagine a 100w standard work light.  They're really bright, hot and dangerous.  Imagine holding that bare bulb in your hands.  THAT'S what 100wrms feels like!  So if that's what 100w is, how can a speaker company rate a speaker do be double that and not be called a liar?  Simple.  Different makers use different methods of ratings.  Some companies rate their speakers as a "Thermal", rating.  Meaning when they fail or catch on fire, e.g. old Orion XTR woofers.  Some use some very good math and measurements but those numbers still don't address frequency or enclosure size.  None of them ever address the amount of RUN TIME that the driver can deal with that kind of heat.  All of a sudden, 400w becomes an oven in a space the size of your fist.  How long can your woofer deliver awesomeness?  Is that sine wave?  Is it random pink noise?  Is that for an 'optimal' enclosure size?  What is optimal about the enclosure?  Is it for SPL or SQ?  Is it to get the most low end?  What's considered low end?  20Hz?  30Hz? 40Hz?  With a filter or without? Xmax vs Xmech?  110 or 220 VAC?

   Dan Wiggins went through this with his clients when he started Adire Audio.  Here's a paper that shows how the Brahma did with all that power.   After reading the paper, you'll see that enclosure size has everything to do with power handling numbers.  As always, there is a compromise.  You can have great output at 30Hz, but you can't throw 1600wrms at it and expect it to survive... At least not that driver.  Now if you have an Adire Parthenon, that's a different story.

    Can you rebuild a speaker to handle more power?  Yes, but you loose the ability to play deep.  You simply re-build the speaker with higher power handling features like direct connect leads, stiffer suspension, maybe even a lighter cone.  So now your rubber band / woofer is much beefier and tighter.  Can you abuse it more? Yes.  Does it handle six gazillion watts? Yes, but now because of the stiffer suspension it has trouble with the low end which is sorta the whole point to having a woofer in the first place.  To get around this, you can add mass to the driver, you can even put it in a bigger box but you're still limited by excursion to get the loudness at the depth you're looking for.  And now you've killed the sensitivity of the driver by adding mass to it.  There are several ways to get around these problems.  A great example of this is also from JL Audio.  The W7 series.

    Displacement = Bore x Excursion, this is the key to moving lots of air.  Since not everyone can have a 50" sub-woofer in their car, excursion will have to be your friend if you want to make really low sounds quite loud.  The W7 series from JL Audio does a great job of this.  They start out with a healthy amount of magnetic material, the motor as it's called.  Add a tight gap and a soft, as well as large suspension and you've got a winner.  Click the link above and then click on the Specifications tab.  You'll see their cool power graph on what's acceptable.  (More on how JL and other brands cheat at this later.)

    OK, so when you look at these graphs, that's the power that's applied, not the amplifier size.  I get asked all the time, "What size amp do I need?", that's a whole other blog entry I'll make about selling / buying.  Basically, whatever you can afford is the bottom line and then you can deal with that. Since you can afford what you can afford, that's what you go with.  So then the question becomes, "Should I buy a popular brand like JL or Kicker or will a generic China made amp do the same job?"

Check back in a few days, bookmark the page or subscribe to this blog and / or our YouTube channel.

The new video will show you how to make the Mojo / LVS woofer more reasonable or just re-cone it.

Thanks as always,
Patrick Chandler
Co-Founder of Robot Underground

Friday, March 1, 2013

Baffle Step Compensation / Does the shape or size of the baffle affect my sound?

    I was recently asked about something called Baffle Step Compensation Then followed up with the next question does the shape of the enclosure affect the sound?

    If you click the link, you'll learn a bit about BSC.  What the article doesn't really get into is how many makers compensate for it and where it's applied.  Yes the outside baffle, (not enclosure), but baffle shape can affect sound.
    Note the frequencies that it affects which are in the upper range.  You can sometimes see this in high end speakers when foam is placed around the mids and tweeters to dampen them and allow the sound to be more pinpoint.  I found SALK to have a better explanation of BSC.  This is why it's key to have your highs pointed at your head.  The the high frequency sounds are highly directional.  This is why many tweeter makers will apply a lens to help disperse the sound.  A horn loaded tweeter can do even more but you compromise the size and place you can place such an object.

    To eliminate this, some makers will remove the baffle entirely like this popular B&W speaker. Notice that they even used truncated frames and large beveled edges on the sides of the woofers.  In this setup, the woofers may be crossed over as high as 350Hz which would still make them subject to some of the BSC rules, (depending on baffle size of course).  Some makers will surround the tweeter and mid-range area with felt or foam.  On many of the speakers the treatments would be removable so you could play with your options as many audiophiles like to do.  An L-Pad in the crossover would do the same thing as well.  Then again, music is subjective.  You may enjoy the added brightness by the effect.

    BSC doesn't affect lower frequencies like that of subwoofers.  The wavelengths are just so much larger that it doesn't matter.  Which leads to the next question, does ENCLOSURE shape affect sound.  The short answer is NO, only the volume matters for subwoofers that is.  as for a speaker or satellite that plays in the upper frequencies, it can have great effect. Heat and cold have an even greater affect on your system. More on that next week from SpeakerBuilder Magazine.

Co-Founder of Robot Underground
Patrick Chandler

Sunday, February 3, 2013

Super Bowl Specials ALL MONTH!

A few specials we'll be working on this month!

     Due to the Diamond / Cerwin Vega closeouts, we also got our hands on some WCC, (West Coast Customs), speakers that were made by the factory that also makes some of the Diamond and Cerwin Vega products.

     We have the WCC680 convertible 5x7" / 6x8" components. Use them as a coax or separates, it's up to you! $55 shipped!

     MSRP was $199 but we have them for $55 a set shipped and limited to 25 sets.  As with all our deals, we can drop ship to your client with your return address, (Blind drop ship), so we stay underground and you're the hero.

     We received a new shipment of the new MA Audio HardKore motors and are already building them out to order.  We're doing the 15" in either D2, D4 or D.75 ohm setups with SPLX frame for only $263 shipped!  (Add $15 for extended 60mm tall coil.)

     You even get the Audio Pulse, aircraft grade aluminum single dish cone with tall, patented NBR surround by TC Sounds.
12" version is $250 each shipped. (Lower 48)
Thanks again to MA Audio for donating their old magnetizer to us at a great discount!

     Not pictured are the 10" version and 18" versions.  We have several cone options to choose from so prices will vary on how fancy pants you want to get with those, but are based on the 12" and 15" pricing.  We do not have 8", 10" or 18" Audio Pulse cones at this time.
     The new style HK motor is shown on the SPLX frame with the SPLX, (TC9+ motor), to the right for comparison.  (No more fins, yay!)


     We also found another stash of the old Rockford White Wolf 3m RCA's.  These are some of the best built cables on the planet!  Get a set for only $30 each shipped to anywhere in North America!  We also ship worldwide and they come in the original box as pictured.  Some still have the Best Buy pricing tags on them as well.  These are a STEAL compared to the prices you home audiophiles pay for a quality cable like this!!!

      These are available to Rockford Fosgate fans all over the world too.  Thank you for your support!

     Rockford Triple X series RCA's are available out of the packaging and tested as well!  We have pallets of RCA's and other cables and we can also custom make several rare cables so email me with your requests.

The 1m is only $16 shipped and 2m is $25 shipped

Thanks again for your support!
Patrick Chandler
Co-Founder of Robot Underground

Friday, January 25, 2013

Why do you do it? Why not for profit? How to build a Robot PART 2

Read part 1 HERE

Step Four:  Let the Wrecking Ball Fly

     Whenever something is built, something else must be un-built / destroyed.  These are not my rules, these are the rules of the universe.  The universe on both the large scale and the very tiny are in constant expansion and contraction, ebb and flow as it were.  When I started my journey, I had no idea of the destruction I would do just to follow my dream.  I didn't mean to harm anyone, in fact I did my best to help others.  What I realize now is that no matter what you do or what anyone else does in this world, there is always give and take.  Every time you help someone, you also hurt someone or something else in order to do it.  Think of all the millions of sperm and generations of people that have died so that you could live.  In order for me to live other things have had to die.  Cows and Chickens top the list.  In spite this, many of us still reach for The Light to make this a better society and generally a great place to live and die.

     If you do something great in your life, expect resistance from others.  Family, long time friends and you may even be betrayed by both to keep you in (your) place.  Governments, agencies and even the Universe may be on this list of resistance givers, (haters).  (Yes the Universe can hate on you).  The trick I've found to being efficient at this is patience mixed with timing.  Sometimes it can't wait but if it can, keep it and wait for the right timing to make your move. To go with the flow as it were.  That requires observation and conscientious action.  If it can't wait, don't be surprised when it's more work that you'd like or thought it should be.  Owning the decision, (follow through), is always a required ingredient to getting to your goal.  At then end of the day, enjoy the fact that you are pursuing a life of adventure and it's a privilege to do it.  The attitude is simply to be grateful.  Even what seems as a life of survival can be turned into adventure by a simple change in attitude.  I'm sure there's a quote somewhere of something like, "Only loving what you have, can you have something else." or "You cannot shake hands with a closed fist.".  The secret is gratitude and that then allows you to enjoy the ride and then everything becomes an adventure.  This is reflected in our mascot, Ohmey.  His mind is always 'open' to allow The Light inside.

Step Five:  Replace Yourself / Get the Robot(s) Running

     Patience and timing are especially crucial to this step.  In order for this project / life to really do something you need to replace yourself. You need the help of others.  You can do this with projects that you do, books or blogs that you publish or even just raising children that don't burn the house down when you decide to go out for a night on the town.

    Our ideas, discoveries and self reflection are what's missing in the world.  In other words, consciousness.  The outward expression of consciousness is change.  To make corrections around us and align ourselves with The Light.  This is where the employment of robots or any device that allows you to leverage your time and knowledge to move you closer toward your goal / life achievement.  The internet is by far the most important and under utilized tool in your arsenal.  This tool at it's present state is still just a tiny flag in the top of an iceberg the size of the Death-Star, we have only scratched the surface.  An even greater asset than that is of course your mind.

   Align yourself and your robots with people and organizations that do this for other people already.  Learn their secrets and watch their moves. (Patience & Timing)  Then when you see the cogs flowing in the right light, jump in to seize your time in the machine and move through without a scratch.  This is where "applying yourself" comes into play. If you want to be good at business, study businesses.  If you want to be the master of Yoga, study everything you can learn about Yoga.  If you want to own the market on Yoga businesses, study franchising and clique culture along with everything about Yoga and Business.  Once you realize their tricks, the secrets of their success.  With the right timing and positioning,(more timing and patience), the world can be yours.

Robots Running!
Patrick Chandler
Co-Founder Robot Underground

Tuesday, January 22, 2013

Diamond Audio 2012 Closeouts - Make An Offer!


Still have the amps left.
$500 ea. - 2 pcs - HA750.1 - 750wrms 1ch, class D & 1 ohm stable, (JL HD750 is not 1 ohm stable)

Again, do your research and make an offer!  All items here are new in the box but do not carry any warranty.  All sales are final and again, thank you for your support.

Patrick Chandler
Co-Founder - Robot Underground