Mazda MX-6 Forum banner

1 - 20 of 35 Posts

·
Premium Member
Joined
·
3,023 Posts
Discussion Starter #1
OK, I'm overdue for a new info post, and I've had lots of questions recently about what to get in what order, how to set gains & crossovers etc, and basic troubleshooting. All these things come under the heading of "basic system design, layout, and tuning" in my mind, so here we go. There will inevitably be differences of opinion here. Feel free to bring these up, this is a good place to discuss them - but as always, this is a thread to teach those newer to the 12-volt world some basics, so keep everything factual and calm, please!

An audio system is going to consist of a few necessary parts. A source (CD player, etc), an amplifier (this is anything that sends power to the speakers, whether it be deck power or an outboard amp), signal procesing (pasive or active, explained later) and speakers. The stock system in most cars is a so-so source, with either bad or so-so amplification and signal processing, and speakers ranging from bad to decent. This industry exists for those who like their music enough to invest time and money into improving on this setup, if not outright replacing it! So, begining with what does what and how to get the most out of it -

Source - The deck supplies the signal for the rest of the system. Period. If you like flashy lights and graphics and other stuff, that's your call, but do not sacrifice quality to get these things or the rest of your system will suffer!

Amplifier(s) - THeir job is to take a small amount of power and make it more powerful. Again, you can get models that do all kinds of crazy things and look cool, but a basic amp that does it's job is better than one that has flashy L.E.D.'s and plexi for the same money.

Crossover(s) (also called x-overs) - Divide's the audio spectrum to send the right frequencies to the right speakers. Without them, things sound bad real fast, and speakers die horrible deaths.

Speakers - From subs to tweeters, having the correct driver for the correct part of the sound spectrum is essential. There are lots of opinions out there, follow your ears when selecting a speaker, no one can tell you what you like!

Speakers are the single most important part of the equation, they are what you listen to! However - the best speakers in the world sound like crap if they don't have a good signal, in fact, a bad speaker will mask distortion, a good one is true to it's signal - so all the crap will shine through! Because of this, a firm foundation must be planted, and that means clean power. I say that the first step in any system is a decent amp, unless you don't have a CD player. Deck comes first if you need to change the source type or your existing one doesn't work. Assuming that the stock setup has a CD player and the speakers aren't blown, the first step is an amp and a sub.

The reason for this is simple: The stock speakers are OK, they're just playing full range with not enough power. Distortion will kill a speaker before power will every time. When you have a speaker playing full range, the lower frequncies (below about 100 Hz) take about 2/3's of the available power, leaving precious little available for the bulk of the music. In order to play these low frequencies well, a speaker needs a LOT of power and needs to move a LOT of air, which means a LOT of motion. Asking a small speaker to do the job of a big one is going to limit the sound you get, and if pushed, will result in blown speakers. By cutting the low frequncies from the small speakers and dedicating a speaker that is made to handle them to that task, your stock speakers will be loud and clean, and you'll find an octave or two of your music that you didn't know you were missing!

There are two ways to do this in the begining - run the highs off the deck and get an amp for the bass, or get a multi channel amp or seperate amps to power the whole system. It will depend on your budget more than anything else. The cheapest way to do things is to turn the bass down ALL THE WAY DOWN on your deck - this reduces the power consumed and the distortion produced by your poor little speakers - and get an amp to the sub with a bass boost set to about +12 Db to compensae for the reduced signal. Alternatively, you can get an amp with built-in x-overs to cut the bass out of the highs, and leave the tone controls alone. This is better, but more expensive. A third solution is some new decks with HP x-overs for their onboard power, a good in-between if you went with a new deck in the begining, but not for this scenario.

Next on the list will be speakers. Now that we have a good power base and a sub, we want to get speakers that play like we want. Follow your ears. A coaxial speaker has the tweeter mounted in or on the mid. This type of speaker is more efficient, easier to install, and cheaper. A component set (seperates) will have a seperate mid and tweet. This allows for more versatility in speaker placement, and the use of an outboard crossover usually means higher power handling. More work, and more money, but more sound.

So now we have a clean power base, and good speakers, with some bass. For many, this is enough! But now we can start into the details. Personaly, I consider a new deck to be a detail, except as outlined above. By getting the new deck, we send cleaner power to the amp, so we get cleaner sound out of the amp. Beyond that, it's a matter of getting the features we want for more enjoyment of the system - a seperate volume control for the woofer, MP3 playback, a multi-disc changer, and those funky graphics that every manufacturer but Eclipse seems to thing are so darn special.

Now we have a complete system, EQ's and stuff can be added as we delve deeper. Right now, all this stuff needs to get set up correctly.

This is a basic overview of who what when where and why. How is discussed in some of my other stickies on impedance, voltage, and box design, as well as others still to come. We will assume here that you have the right wires, the right box, and the correct impedance speakers and subs for your system, and get into getting it all tuned correctly.

Active crossovers. Most amps have these built in, so do some decks. I do not usually recomend using deck x-overs, they aren't all that accurate. But they're beter than nothing. Try not to stack them unless you really know what you're doing - if both deck and amp have built in x-overs, use the one with the better range of adjustment, not both. On the amp, there are three types, switched, selectable, and adjustable/variable. Switched will be ON/off at a set frequency. Not the best, we may want another frequency - but better than nothing. Selectable will be a switch with several set frequency options, this is better. Adjustable or variable will have a continuously adjustable range with which to set the frequency, usually 50 to 500 or so. This is pretty simple - you want the frequency to match the size speakers you have. Smaller speakers need to be crossed higher (less bass) larger ones can be lower (stronger midbass). Subs are all about the same - contrary to popular belief, big woofers don't NEED to be crossed lower. Crossover slopes and subsonic filters will be attacked later, in a more in-depth thread. Small speakers (3.5 to 5.25 inches or so) should be HP in the 100 to 150 range, higher with more power. Medium speakers (6 and 6.5's, 5x7, 6x8, 6x9, etc) will be in the 80 o 120 range. Subs usualy work best LP between 70 and 100. Play with it once your gains are set to get what you're after.

Amplifier gains. These are RARELY set correctly, even by pro's. In a perfect world, they would not be necessary! All decks would have a standard preamp signal voltage, and amps would be set accordingly at the factory. Such is not the case, however. Gain is not there to make things louder. Gain is there to match the amps input section with the sources output voltage. Some decks have vary low preamp voltage, .5 to 1.2 volts or so. Some have very high output voltage, 4, 5, 8 - even 16 volts in some cases. The gain control on the amp will have a given range, usually .5 to 5 volts nowadays. You set the gain on the amp as close as possible to the max output on the deck, plus a little - the deck seldom puts out maximum preamp voltage, and some CD's are recorded louder than others. The easiest way to do this is by ear, believe it or not. Put on some very powerfull, full-range music. Heavy modern rock bands and loud classical music are best, rap and techno have very little signal acroos the full range, and don't get a lot of output. Turn the gain ALL THE WAY DOWN, and the deck volume ALL THE WAY UP, in that order. Begin turning up the gain SLOWLY, until you begin to hear distortion, and stop. Done! Hopefully, this is louder than you will listen to your music 90% of the time. If not, DO NOT INCREASE THE GAIN! You need more power, get a bigger amp!

We now have a clean little system, that has some bass, plays loud & clean, and doesn't run the risk of blowing up any time soon. Unfortunately, this means you are now addicted, and will be expanding the system in the near future. })

I hope this gives people new to the stereo world an idea of where to start, and how to avoid blowing up the stuff they start with. There is a lot more to cover here, and it will be covered. I hope we get a lot of discussion going on this one, as it will enhance the effectiveness of this thread - so please comment and question away!
 

·
Registered
Joined
·
5,869 Posts
Amp and sub before deck and speakers?

I think that for 99 percent of people and what they want from their audio, you hit the nail right on the head man. Thats a tough one to sell to me, but the more I think of it, the more it makes sense. Once again you have created a document that will help countless others. Karma for you :D
-Garrett
 

·
Premium Member
Joined
·
3,023 Posts
Discussion Starter #3 (Edited)
LOL - that perspective pays my rent, too.

After years in the business, and taking an attitude of genuinely caring about my customers needs, I figured out that this works, as you said, 99% of the time. Many people spend money on the new deck, and think they have a new "stereo", and are disappointed when the sound difference is marginal at best. When I get cross-shopped, every other shop tried to sell them a new CD player, and I'm wya out to left field saying keep your stock setup for now if it's got CD. It's a different view, and when I fire it up on the sound board, they're done!

The amp/sub first is the biggest difference in sound for the initial investment.

Anyway, thanx for the reply - this was less technical and not as artfully written as my others, and not getting any action - I was begining to think it sucked and I should remove or rewrite it!
 

·
Registered
Joined
·
1,858 Posts
Excellent writeup! As always!

One addition - turning the gain to "halfway" on a 400W amp (for example) doesn't make it run at 200W people! I hear this so often it makes me sick....
 

·
Registered
Joined
·
25 Posts
What is the best thing to look over on an amp ? I am currently searching for one and its not easy to choose. I was wondering about getting a Phoenix Gold XS2500 one. I have 2 12 Phoenix Gold XS124 250 wrms each, so it could be ok. But I am still looking over amps !

Remember, I just got into the sound game, so it's my first amplified sound system ( I have a 626).
 

·
Premium Member
Joined
·
3,023 Posts
Discussion Starter #8
Start a new thread, you'll get a lot of answers and different opinions.

The XS2500 is an oldie but goodie, very good amplifier, perfect for a couple of (8 ohm or dual 4 ohm coil) 12's.
 

·
Registered
Joined
·
228 Posts
Personally I as a owner to of a shop, I would buy a new deck first because the stock cd players are only kicking out like 13 watts. I would start with a good deck with several pre-outs. It all depends what a person is going for. Any questions email me
 

·
Premium Member
Joined
·
3,023 Posts
Discussion Starter #11
Karma? :)


77 - There are certainly situations where a better deck is called for, but my reasoning (with something like 11 or 12 years in the industry behind it) is that that 13 or so watts is better off providing a signal for an amp than going o speakers, and that an amp with crossovers sending better power and a cleaner signal to whichever speakers (stock or aftermarket) will make a bigger difference in sound than just replacing the deck for a similar investment. Every system I ever do has an eye on expansion.... ;)
 

·
Registered
Joined
·
22 Posts
question- what should i do about the incessant rattling that has by now driven me off my rocker?? I hear dynamatt is effective, but i would have to lay it in my trunk, above my back seats, my doors, dash everything. heeeelp me please, and i am only pushing 500watt, with two 12" treos.

sorry, i looked two topics down on this forum and realized i am an idiot, thanks., no need to reply
 

·
Registered
Joined
·
16 Posts
Actually i feel in all due respect the source unit is the first to go hands down.
IF you buy a amp and sub then you still have limited frequency response from your factory head unit.
By getting a aftermarket source unit with sub control you open up your frequency range and input voltage to the sub.
Basically buying a head unit first is priority because not only will it give you greater frequency responsive 90 percent of your sound which comes from the inside will sound much cleaner if you buy the right unit it will have a hpf and a slope adjustment. Your distortion will be almost none and the sound will be more full and rich. Just buying a sub is only solving 10 percent of the issue so i will have to disagree with your assesment and i speak from experience not to discount yours.

overall very informative and knowledgable


sincerely a fellow industry pro
 

·
Premium Member
Joined
·
3,023 Posts
Discussion Starter #15
Point taken, and shared by many or most of the industry. If the source unit is changed, but you rely on the source units amplification and the stock speakers, you actually hear very little of that increased range. The amp/sub addition makes a bigger difference in the overall sound as a first step. :shrug:
 

·
Registered
Joined
·
20 Posts
having your subs in the very middle of the trunk, i always thought put out a very good sound, it evens it out through out the car and makes for apretty good set up.
 

·
Registered
Joined
·
90 Posts
I have a tape deck, and I use the tape hookup to a portable CD player....should I just get a cheap (like50-70 CD deck) and get an amp? or should I just stick with the tape hookup and spend that 50-70 bucks on an amp?

like is it worth it to change my tape deck to $150 plus CD deck (pioneer, SONY)
 

·
Premium Member
Joined
·
3,023 Posts
Discussion Starter #19
You can get a really good CD player for $150 to $200 these days, anything else (tape adaptor, etc) that costs less is a waste of money. More expensive decks, just depends on whether you'll actually use the extra features. :shrug:
 

·
Registered
Joined
·
51 Posts
when i put the system in my car, the head unit was the first to go, because i knew i wanted subs, i bought those last. needless to say, i bought a clarion apa-450 amp (4x50 rms 4x100 max) a set of pioneer 4 way 6x8 speakers, and a set of infinity 6x8s for the back. then came the subs. i got an amazing deal on those that i couldnt pass up. but in either case it was a power acoustik 2x600 (2x300 rms?) max amp with 2-12" rockford p-1s.. the only reason i did it in that order, was because i knew i would set money aside for the subs, and i didnt want to slack in other areas of the car. and does anyone know about how many square feet of dyna style mat it would take to cover my trunk area? and also does anyone know of a discount place (website) to buy it?

thanks,
kevin
 
1 - 20 of 35 Posts
Top